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1
Wang, Hong Wei, Chen Jie Qi, Qiu Xin Wu, Qi Mu Surong und Zhen Hua Xing. „Signal Decomposition for Three-Axis Gyroscope“. Advanced Materials Research 346 (September 2011): 521–26. http://dx.doi.org/10.4028/www.scientific.net/amr.346.521.
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Study Algorithm of roll, pitch and yaw angular velocity for three-axis gyroscope. the gyro have only one sensitive quality, can sensitize the three axial angular velocity of the rotating carrier at the same time. in the case of gyro’s spin angular velocity presence and pitch or yaw angular velocity worked, gyro output signal contain spin, pitch and yaw angular velocity. Through Uniaxial Gravity Accelerometer’s application, the roll, pitch and yaw angular velocity for three-axis gyroscope can be demodulated.
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John, J., und T. Schobeiri. „A Simple and Accurate Method of Calibrating X-Probes“. Journal of Fluids Engineering 115, Nr. 1 (01.03.1993): 148–52. http://dx.doi.org/10.1115/1.2910098.
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This paper presents an improved method of calibrating hot-film X-probes in incompressible flow. The yaw response of a hot-film X-probe was investigated for different velocities and found to be strongly velocity dependent at low velocities. A simple relation was developed to correct for the variation of yaw response at low velocities. The method using the yaw correction is compared with the single-velocity yaw calibration method. The correction to the yaw response considerably improves accuracy at low velocities.
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Sun, Tao, Hao Guo, Jian-yong Cao, Ling-jiang Chai und Yue-dong Sun. „Study on Integrated Control of Active Front Steering and Direct Yaw Moment Based on Vehicle Lateral Velocity Estimation“. Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/275269.
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Considering the vehicle lateral velocity is difficult to be measured at integration of chassis control in configuration of production vehicle, this study presents the vehicle lateral velocity estimation based on the extended Kalman filtering with the standard sensor information. The fuzzy control algorithm is proposed to integrate direct yaw moment control and active front steering with lateral velocity estimation. The integration controller produces direct yaw moment and front wheel angle compensation to control yaw rate and sideslip angle, which makes the actual vehicle yaw rate and sideslip angle follow desirable yaw rate and desirable sideslip angle. The simulation results show vehicle handling and stability are enhanced under different driving cycles by the proposed algorithm.
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Walker, Mark F., und David S. Zee. „Cerebellar Disease Alters the Axis of the High-Acceleration Vestibuloocular Reflex“. Journal of Neurophysiology 94, Nr. 5 (November 2005): 3417–29. http://dx.doi.org/10.1152/jn.00375.2005.
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L. W. Schultheis and D. A. Robinson showed that the axis of the rotational vestibuloocular reflex (RVOR) cannot be altered by visual-vestibular mismatch (“cross-axis adaptation”) when the vestibulocerebellum is lesioned. This suggests that the cerebellum may calibrate the axis of eye velocity of the RVOR under natural conditions. Thus we asked whether patients with cerebellar disease have alterations in the RVOR axis and, if so, what might be the mechanism. We used three-axis scleral coils to record head and eye movements during yaw, pitch, and roll head impulses in 18 patients with cerebellar disease and in a comparison group of eight subjects without neurologic disease. We found distinct shifts of the eye-velocity axis in patients. The characteristic finding was a disconjugate upward eye velocity during yaw. Measured at 70 ms after the onset of head rotation, the median upward gaze velocity was 15% of yaw head velocity for patients and <1% for normal subjects ( P < 0.001). Upward eye velocity was greater in the contralateral (abducting) eye during yaw and in the ipsilateral eye during roll. Patients had a higher gain (eye speed/head speed) for downward than for upward pitch (median ratio of downward to upward gain: 1.3). In patients, upward gaze velocities during both yaw and roll correlated with the difference in anterior (AC) and posterior canal excitations, scaled by the respective pitch gains. Our findings support the hypothesis that upward eye velocity during yaw results from AC excitation, which must normally be suppressed by the intact cerebellum.
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Emirler, Mümin Tolga, Kerim Kahraman, Mutlu Şentürk, Bilin Aksun Güvenç, Levent Güvenç und Barış Efendioğlu. „Vehicle Yaw Rate Estimation Using a Virtual Sensor“. International Journal of Vehicular Technology 2013 (24.04.2013): 1–13. http://dx.doi.org/10.1155/2013/582691.
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Road vehicle yaw stability control systems like electronic stability program (ESP) are important active safety systems used for maintaining lateral stability of the vehicle. Vehicle yaw rate is the key parameter that needs to be known by a yaw stability control system. In this paper, yaw rate is estimated using a virtual sensor which contains kinematic relations and a velocity-scheduled Kalman filter. Kinematic estimation is carried out using wheel speeds, dynamic tire radius, and front wheel steering angle. In addition, a velocity-scheduled Kalman filter utilizing the linearized single-track model of the road vehicle is used in the dynamic estimation part of the virtual sensor. The designed virtual sensor is successfully tested offline using a validated, high degrees of freedom, and high fidelity vehicle model and using hardware-in-the-loop simulations. Moreover, actual road testing is carried out and the estimated yaw rate from the virtual sensor is compared with the actual yaw rate obtained from the commercial yaw rate sensor to demonstrate the effectiveness of the virtual yaw rate sensor in practical use.
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Schottler, Jannik, Jan Bartl, Franz Mühle, Lars Sætran, Joachim Peinke und Michael Hölling. „Wind tunnel experiments on wind turbine wakes in yaw: redefining the wake width“. Wind Energy Science 3, Nr. 1 (16.05.2018): 257–73. http://dx.doi.org/10.5194/wes-3-257-2018.
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Abstract. This paper presents an investigation of wakes behind model wind turbines, including cases of yaw misalignment. Two different turbines were used and their wakes are compared, isolating effects of boundary conditions and turbine specifications. Laser Doppler anemometry was used to scan full planes of wakes normal to the main flow direction, six rotor diameters downstream of the respective turbine. The wakes of both turbines are compared in terms of the time-averaged main flow component, the turbulent kinetic energy and the distribution of velocity increments. The shape of the velocity increments' distributions is quantified by the shape parameter λ2. The results show that areas of strongly heavy-tailed distributed velocity increments surround the velocity deficits in all cases examined. Thus, a wake is significantly wider when two-point statistics are included as opposed to a description limited to one-point quantities. As non-Gaussian distributions of velocity increments affect loads of downstream rotors, our findings impact the application of active wake steering through yaw misalignment as well as wind farm layout optimizations and should therefore be considered in future wake studies, wind farm layout and farm control approaches. Further, the velocity deficits behind both turbines are deformed to a kidney-like curled shape during yaw misalignment, for which parameterization methods are introduced. Moreover, the lateral wake deflection during yaw misalignment is investigated.
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May, M. L., und R. R. Hoy. „Ultrasound-induced yaw movements in the flying Australian field cricket (Teleogryllus oceanicus)“. Journal of Experimental Biology 149, Nr. 1 (01.03.1990): 177–89. http://dx.doi.org/10.1242/jeb.149.1.177.
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An ultrasonic stimulus induced negative phonotactic steering in the yaw axis of tethered, flying Australian field crickets. The forewings, hindwings and twisting of the thorax generated the forces which induced the yaw turn. However, abdominal ruddering did not contribute to yaw turns. Each aspect of the yaw steering response depended upon the stimulus intensity. At higher ultrasonic intensities, the magnitude and average angular velocity increased while the latency of the yaw turn decreased. Each of these factors varied in a graded manner, revealing that this behavior is more complex than a simple reflex.
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Killian, J. Eric, und James F. Baker. „Horizontal Vestibuloocular Reflex (VOR) Head Velocity Estimation in Purkinje Cell Degeneration (pcd/pcd) Mutant Mice“. Journal of Neurophysiology 87, Nr. 2 (01.02.2002): 1159–64. http://dx.doi.org/10.1152/jn.00219.2001.
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The horizontal vestibuloocular reflex (VOR) of Purkinje cell degeneration ( pcd/pcd) mutant mice, which lack a functional cerebellar cortex, was compared in darkness to that of wild-type animals during constant velocity yaw rotations about an earth-horizontal axis and during sinusoidal yaw rotations about an earth-vertical axis. Both wild-type and pcd/pcd mice showed a compensatory average VOR eye velocity, or bias, during constant velocity horizontal axis rotations, evidence of central neural processing of otolith afferent signals to create a signal proportional to head angular velocity. Eye velocity bias was greater in pcd/pcd mice than in wild-type mice at a low rotational velocity (32°/s), but less at higher velocities (128 and 200°/s). Lesion of the medial nodulus severely attenuated eye velocity bias in two wild-type mice, without attenuating VOR during sinusoidal vertical axis yaw rotations at 0.2 Hz. These results show that while head velocity estimation in mice, as in primates, depends on the cerebellum, pcd/pcd mutant mice develop velocity estimation without a functional cerebellar cortex. We conclude that neural circuits that exclude cerebellar cortex are capable of the signal processing necessary for head angular velocity estimation, but that these circuits are insufficient for normal estimation at high velocities.
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Lafortune, S. H., D. J. Ireland und R. M. Jell. „Effect of active head movements about the pitch, roll, and yaw axes on human optokinetic afternystagmus“. Canadian Journal of Physiology and Pharmacology 66, Nr. 6 (01.06.1988): 689–96. http://dx.doi.org/10.1139/y88-110.
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Effects of active head movements about the pitch, roll, or yaw axes on horizontal optokinetic afternystagmas (OKAN) were examined in 16 subjects to test the hypothesis that otolith organ mediated activity induced by a change in head position can couple to the horizontal velocity storage in humans. Active head movements about the pitch axis, forwards or backwards, produced significant OKAN suppression. Pitch forward head movements exerted the strongest effect. Active head movements about the roll axis towards the right also produced OKAN suppression but only if the tilted position was sustained. No suppression was observed following sustained yaw. However, an unsustained yaw left movement after rightward drum rotation significantly enhanced OKAN. Sustained head movement trials did not significantly alter subsequent control trials. In contrast, unsustained movements about the pitch axis, which involve more complex interactions, exerted long-term effects on subsequent control trials. We conclude that otolith organ mediated activity arising from pitch or roll head movements couples to the horizontal velocity storage in humans, thereby suppressing ongoing OKAN. Activity arising from the horizontal canals during an unsustained yaw movement (observed mainly with yaw left), following drum rotation in a direction contralateral to the movement, may also couple to the velocity storage, resulting in increased activity instead of suppression.
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Zhao, Ming Hui, Lian Dong Wang, Lei Ma und Hui Hou. „Control Methods of Active Front Wheel Steering for 4WD Electric Vehicle“. Applied Mechanics and Materials 97-98 (September 2011): 735–40. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.735.
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Based on two freedom degrees of vehicle model, control method which takes yaw rate and sideslip angle as system state, and front wheel corner and direct yaw moment as control input is put forward. Considering uncertainty of velocity and direct yaw moment, feedforward-feedback controllers are designed. Four wheel drive force are allocated by using feedforward compensation and yaw moment which is formed by driving force difference value. It makes yaw rate and sideslip well of tracking the desirable model when the vehicle drive steering. Finally, vehicle handling stability is studied on conditions of step input and sine input by simulation.
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Arai, Yasuko, Sergei B. Yakushin, Bernard Cohen, Jun-Ichi Suzuki und Theodore Raphan. „Spatial Orientation of Caloric Nystagmus in Semicircular Canal-Plugged Monkeys“. Journal of Neurophysiology 88, Nr. 2 (01.08.2002): 914–28. http://dx.doi.org/10.1152/jn.2002.88.2.914.
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We studied caloric nystagmus before and after plugging all six semicircular canals to determine whether velocity storage contributed to the spatial orientation of caloric nystagmus. Monkeys were stimulated unilaterally with cold (≈20°C) water while upright, supine, prone, right-side down, and left-side down. The decline in the slow phase velocity vector was determined over the last 37% of the nystagmus, at a time when the response was largely due to activation of velocity storage. Before plugging, yaw components varied with the convective flow of endolymph in the lateral canals in all head orientations. Plugging blocked endolymph flow, eliminating convection currents. Despite this, caloric nystagmus was readily elicited, but the horizontal component was always toward the stimulated (ipsilateral) side, regardless of head position relative to gravity. When upright, the slow phase velocity vector was close to the yaw and spatial vertical axes. Roll components became stronger in supine and prone positions, and vertical components were enhanced in side down positions. In each case, this brought the velocity vectors toward alignment with the spatial vertical. Consistent with principles governing the orientation of velocity storage, when the yaw component of the velocity vector was positive, the cross-coupled pitch or roll components brought the vector upward in space. Conversely, when yaw eye velocity vector was downward in the head coordinate frame, i.e., negative, pitch and roll were downward in space. The data could not be modeled simply by a reduction in activity in the ipsilateral vestibular nerve, which would direct the velocity vector along the roll direction. Since there is no cross coupling from roll to yaw, velocity storage alone could not rotate the vector to fit the data. We postulated, therefore, that cooling had caused contraction of the endolymph in the plugged canals. This contraction would deflect the cupula toward the plug, simulating ampullofugal flow of endolymph. Inhibition and excitation induced by such cupula deflection fit the data well in the upright position but not in lateral or prone/supine conditions. Data fits in these positions required the addition of a spatially orientated, velocity storage component. We conclude, therefore, that three factors produce cold caloric nystagmus after canal plugging: inhibition of activity in ampullary nerves, contraction of endolymph in the stimulated canals, and orientation of eye velocity to gravity through velocity storage. Although the response to convection currents dominates the normal response to caloric stimulation, velocity storage probably also contributes to the orientation of eye velocity.
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Marshall, J. S. „Wake Dynamics of a Yawed Cylinder“. Journal of Fluids Engineering 125, Nr. 1 (01.01.2003): 97–103. http://dx.doi.org/10.1115/1.1523069.
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A theoretical and computational study is reported of the effect of cylinder yaw angle on the vorticity and velocity field in the cylinder wake. Previous experimental studies for yawed cylinder flows conclude that, sufficiently far away from the cylinder ends and for small and moderate values of the yaw angle, the near-wake region is dominated by vortex structures aligned parallel to the cylinder. Associated with this observation, experimentalists have proposed the so-called Independence Principle, which asserts that the forces and vortex shedding frequency of a yawed cylinder are the same as for a cylinder with no yaw using only the component of the freestream flow oriented normal to the cylinder axis. The current paper examines the structure, consequences and validity for yawed cylinder flows of a quasi-two-dimensional approximation in which the velocity and vorticity have three nonzero components, but have vanishing gradient in the direction of the cylinder axis. In this approximation, the cross-stream velocity field is independent of the axial velocity component, thus reproducing the Independence Principle. Both the axial vorticity and axial velocity components are governed by an advection-diffusion equation. The governing equations for vorticity and velocity in the quasi-two-dimensional theory can be nondimensionalized to eliminate dependence on yaw angle, such that the cross-stream Reynolds number is the only dimensionless parameter. A perturbation argument is used to justify the quasi-two-dimensional approximation and to develop approximate conditions for validity of the quasi-two-dimensional approximation for finite-length cylinder flows. Computations using the quasi-two-dimensional theory are performed to examine the evolution of the cross-stream vorticity and associated axial velocity field. The cross-stream vorticity is observed to shed from the cylinder as thin sheets and to wrap around the Ka´rman vortex structures, which in turn induces an axial velocity deficit within the wake vortex cores. The computational results indicate two physical mechanisms, associated with instability of the quasi-two-dimensional flow, that might explain the experimentally observed breakdown of the Independence Principle for large yaw angles.
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Fu, Mingyu, Taiqi Wang und Chenglong Wang. „Barrier Lyapunov Function-Based Adaptive Control of an Uncertain Hovercraft with Position and Velocity Constraints“. Mathematical Problems in Engineering 2019 (12.02.2019): 1–16. http://dx.doi.org/10.1155/2019/1940784.
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This paper considers the problem of constrained path following control for an underactuated hovercraft subject to parametric uncertainties and external disturbances. A four-degree-of-freedom hovercraft model with unknown curve-fitted coefficients is first rewritten into a parameterized form. By introducing a barrier Lyapunov function into the line-of-sight guidance, the specific transient tracking performance in terms of position error is guaranteed. A novel constrained yaw rate controller is proposed to ensure time-varying yaw rate constraint satisfaction, in which the yaw rate barrier is required to vary with the speed of the hovercraft. Moreover, a command filter is incorporated into the control design to generate the desired virtual controls and its time derivatives. Theoretical analyses show that, under the proposed controller, the position tracking error constraints and the yaw rate constraint can be strictly guaranteed. Finally, numerical simulations illustrate the effectiveness and advantages of the proposed control scheme.
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Dai, M. J., T. Raphan und B. Cohen. „Spatial orientation of the vestibular system: dependence of optokinetic after-nystagmus on gravity“. Journal of Neurophysiology 66, Nr. 4 (01.10.1991): 1422–39. http://dx.doi.org/10.1152/jn.1991.66.4.1422.
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1. Monkeys received optokinetic stimulation at 60 degrees/s about their yaw (animal vertical) and pitch (animal horizontal) axes, as well as about other head-centered axes in the coronal plane. The animals were upright or tilted in right-side-down positions with regard to gravity. The stimuli induced horizontal, vertical, and oblique optokinetic nystagmus (OKN). OKN was followed by optokinetic after-nystagmus (OKAN), which was recorded in darkness. 2. When monkeys were tilted, stimulation that generated horizontal or yaw axis eye velocity during OKN induced a vertical or pitch component of slow phase velocity during OKAN. This has been designated as "cross-coupling" of OKAN. Eigenvalues and eigenvectors associated with the system generating OKAN were found as a function of tilt. They were determined by use of the Levenberg-Marquardt algorithm to minimize the mean square error between the output of a model of OKAN and the data. 3. The eigenvector associated with yaw OKAN (yaw axis eigenvector) was maintained close to the spatial vertical regardless of the angle of tilt. The eigenvector associated with pitch OKAN (pitch axis eigenvector) was always aligned with the body axis. The data indicate that velocity storage can be modeled by a piecewise linear system, the structure of which is dependent on gravity and the yaw axis eigenvector, which tends to align with gravity. 4. Yaw axis eigenvectors were also determined by giving optokinetic stimulation about head-centered axes in the coronal plane with the animal in various angles of tilt. A technique using a spectral analysis of residuals was developed to estimate whether yaw and pitch OKAN slow phase velocities decayed concurrently at the same relative rate and over the same time course. The eigenvectors determined by this method were in agreement with those obtained by analyzing OKAN elicited by yaw OKN. 5. During yaw OKN with the animal in tilted positions, the mean vector of the ensuing nystagmus was closer to the body axis than to the spatial vertical. This suggests that there is suppression of the cross-coupled pitch component during OKN. The direction of the stimulus may be utilized to suppress components of velocity storage not coincident with the direction of stimulus motion. 6. There were similarities between the monkey eigenvectors and human perception of the spatial vertical, and the mean of eigenvectors for upward and downward eye velocities overlay human 1-g perceptual data.(ABSTRACT TRUNCATED AT 400 WORDS)
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Ji, Yonggang, Yiming Wang, Weimin Huang, Weifeng Sun, Jie Zhang, Ming Li und Xiaoyu Cheng. „Vessel Target Echo Characteristics and Motion Compensation for Shipborne HFSWR under Non-Uniform Linear Motion“. Remote Sensing 13, Nr. 14 (19.07.2021): 2826. http://dx.doi.org/10.3390/rs13142826.
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For shipborne high-frequency surface wave radar (HFSWR), the movement of the ship has a great impact on the radar echo, thus affecting target detection performance. In this paper, the characteristics of the target echo spectrum and the motion compensation methods for shipborne HFSWR are investigated. Firstly, simulation analysis of echo from a moving target under different ship motion conditions was conducted with a focus on the frequency shift and broadening characteristics of the target echo spectrum. The simulation results show that the non-uniform linear motion and yaw of the ship will shift and broaden the target echoes, resulting in signal-to-noise ratio (SNR) reduction. When the ship velocity and yaw angle change periodically, false target echo peaks will appear in the echo spectrum, which will reduce the accuracy of target detection. To tackle this problem, a motion compensation scheme for the target echo is proposed, including the heading compensation for the effect of yaw and the velocity compensation for non-uniform movement. The influence of the velocity and yaw angle measurement accuracy on the compensation results is also analyzed. Finally, the target echo characteristics and motion compensation method of shipborne HFSWR are verified with experimental data.
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Pingan, Zhang, Wang Wei, Gao Ming und Che Jinli. „Attitude Measurement of Special Aircraft Based on Geomagnetic and Angular Velocity Sensors“. International Journal of Aerospace Engineering 2020 (20.11.2020): 1–8. http://dx.doi.org/10.1155/2020/8866463.
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Aiming at the problem of attitude test of special aircraft in flight, the combined test technology of geomagnetic sensor and angular velocity sensor is studied. The mathematical model of special aircraft roll attitude test based on combined measurement is established. The error models of special aircraft roll angle based on yaw angle input and pitch angle input are derived, respectively, and based on the actual flight trajectory data of aircraft, the mathematical model of special aircraft roll attitude test is established The simulation results show that the roll angle error input by yaw angle is between -0.4° and 0.9°, while the roll angle error input by pitch angle is between -0.4° and 1.2°, which shows that the calculation accuracy of roll angle input by yaw angle is higher, and the existence of magnetic measurement blind area is verified. In this paper, the method of judging the blind area of geomagnetic survey and the algorithm model of eliminating the influence of blind area are proposed.
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Theodoropoulos, Stefanos, Dionisis Kandris, Maria Samarakou und Grigorios Koulouras. „Fuzzy Regulator Design for Wind Turbine Yaw Control“. Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/516394.
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This paper proposes the development of an advanced fuzzy logic controller which aims to perform intelligent automatic control of the yaw movement of wind turbines. The specific fuzzy controller takes into account both the wind velocity and the acceptable yaw error correlation in order to achieve maximum performance efficacy. In this way, the proposed yaw control system is remarkably adaptive to the existing conditions. In this way, the wind turbine is enabled to retain its power output close to its nominal value and at the same time preserve its yaw system from pointless movement. Thorough simulation tests evaluate the proposed system effectiveness.
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Li, Chen, Shang Bin Song, Ge Teng Tang und Hui Qi Shi. „Effect of Tractor-Semitrailer Velocity on Cornering Braking Stability“. Applied Mechanics and Materials 697 (November 2014): 334–39. http://dx.doi.org/10.4028/www.scientific.net/amm.697.334.
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A dynamic model of tractor-semitrailer cornering braking was established in this paper. The accuracy of the model was tested and verified by comparing model output with data of tractor-semitrailer test. By model simulation of the cornering braking process, initial speed such as 20km/h, 25km/h, 30km/h, 35km/h, 40km/h was chosen to analyzed the changing curve of braking distance, articulation angle, yaw rate and lateral acceleration. The result shows that during cornering braking of tractor-semitrailer, with the increasing of initial speed, braking distance greatly increased, articulation angle, yaw rate and lateral acceleration are all increasing. Thus, when braking in a turn, the vehicle speed must be reduced to ensure the stability of tractor-semitrailer cornering braking.
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Robinson, F. R., M. O. Fraser, J. R. Hollerman und D. L. Tomko. „Yaw direction neurons in the cat inferior olive“. Journal of Neurophysiology 60, Nr. 5 (01.11.1988): 1739–52. http://dx.doi.org/10.1152/jn.1988.60.5.1739.
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1. Single units that responded to yaw rotation were recorded extracellularly in the caudal inferior olive (IO) of barbiturate-anesthetized cats. Of 276 neurons, 55 responded reliably to yaw, and extensive quantitative data were recorded from 25. 2. No yaw-sensitive IO neuron responded to somatosensory or auditory stimuli but two responded, though unreliably, to flash. 3. Yaw-sensitive IO cells fired at low (1-4 spikes/s), irregular rates during one direction of rotation. Though cells responded reliably during yaw, firing rates varied considerably from cycle to cycle. Rotation speed and acceleration were not represented in any cell's firing rate. 4. Eighty five percent (47/55) of yaw-sensitive cells fired during contralateral rotation, 9% (5/55) during ipsilateral rotation, and 6% (3/55) fired from late in the ipsilateral phase of a sinusoidal oscillation to the middle of the contralateral phase. 5. Responses were tested to 0.1-Hz sinusoidal yaw oscillations with a range of peak angular velocities (1-200 degrees/s). Thresholds were not sharp because of the cycle to cycle variability in response rates but were estimated using averaged responses. The peak rate of the most sensitive cell was driven to criterion (2 SD above spontaneous rate) by an oscillation with a peak velocity of 1 degrees/s. Other cells reached criterion between 5 and 50 degrees/s. 6. Sinusoidal oscillation at all frequencies tested (0.01-0.5 Hz) elicited approximately the same firing rates. Even at 0.01 Hz cells responded well. Responses lagged acceleration by approximately 25 degrees at 0.01 Hz and shifted to later parts of the cycle as frequency increased so that firing lagged acceleration by approximately 200 degrees at 0.5 Hz. 7. Histological reconstruction showed that yaw-sensitive neurons were recorded in olivary subnucleus beta (N beta), the dorsal cap of Kooy (DC), the posterior medial region of the medial accessory division of the inferior olive (MAO), and in the medial-lateral center of the caudal MAO. 8. Yaw-sensitive neurons in the inferior olive provide a signal to the cerebellum that indicates the direction of passive rotation over a wide range of velocity and acceleration. The signal from individual neurons does not reliably encode either rotation velocity or acceleration. Yaw-sensitive IO neurons are therefore unlike other central vestibular neurons but are similar to somatosensory IO cells which signal the presence, but not the intensity of a stimulus.
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Lu, Sen, Kaiming Yang, Yu Zhu, Leijie Wang, Ming Zhang und Jin Yang. „Yaw error correction of ultra-precision stage for scanning beam interference lithography systems“. Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 232, Nr. 7 (02.04.2018): 869–78. http://dx.doi.org/10.1177/0959651818766197.
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The stage yaw error is a key factor affecting the phase distortion of gratings produced by scanning beam interference lithography system. In order to solve this problem, a coarse-fine dual-stage mechanism is proposed, in which an ultra-precision fine positioning stage with yaw error correction function is developed. To achieve nanoscale positioning and sub-microradian yaw motion accuracy, four Lorentz motors are used to drive the fine stage. The internal coupling factors and the mechanism of Lorentz motors motion control are analyzed. Besides, the Abbe error caused by the yaw error is investigated. Positioning and scanning experiments are conducted and the outcomes show that maximum yaw error is 0.33 μrad during constant velocity scanning, which completely meets the grating fabrication requirements.
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Shen, Huan, und Yun-Sheng Tan. „Vehicle handling and stability control by the cooperative control of 4WS and DYC“. Modern Physics Letters B 31, Nr. 19-21 (27.07.2017): 1740090. http://dx.doi.org/10.1142/s0217984917400905.
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This paper proposes an integrated control system that cooperates with the four-wheel steering (4WS) and direct yaw moment control (DYC) to improve the vehicle handling and stability. The design works of the four-wheel steering and DYC control are based on sliding mode control. The integration control system produces the suitable 4WS angle and corrective yaw moment so that the vehicle tracks the desired yaw rate and sideslip angle. Considering the change of the vehicle longitudinal velocity that means the comfort of driving conditions, both the driving torque and braking torque are used to generate the corrective yaw moment. Simulation results show the effectiveness of the proposed control algorithm.
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Hering, Thomas, und Eric Savory. „Flow Regimes and Drag Characteristics of Yawed Elliptical Cavities With Varying Depth“. Journal of Fluids Engineering 129, Nr. 12 (13.06.2007): 1577–83. http://dx.doi.org/10.1115/1.2801365.
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The effect of yaw angle and cavity depth on the resulting flow field of cavities with elliptical planform areas embedded in a low velocity turbulent boundary layer was investigated experimentally. A 2:1 elliptical cavity with depth to minor axis ratios ranging from 0.1 to 1.0 was tested in a wind tunnel facility. Surface pressure measurements and wake velocity measurements, using hot-wire anemometry, were conducted to examine the resulting flow regimes. The results indicated several different flow regimes for the different yaw angle and cavity depth configurations. Cellular structures were observed when the minor axis was aligned with the streamwise direction. Yawing the cavity with respect to the streamwise direction resulted in a highly asymmetric flow regime. This flow regime was also associated with high drag for certain cavity depth configurations. A nominally two-dimensional flow regime was observed for large yaw angles, when the major axis of the cavity was aligned with the streamwise direction. The yaw angle had only a minor effect on the flow regimes associated with the shallowest and deepest cavities examined. A strong resemblance was found between the flow regimes associated with elliptical and rectangular cavities for similar yaw and depth configurations. This similarity was also observed in the lift and drag coefficients for the different yaw angles and cavity depths. This indicated that the wall radius of curvature of elliptical cavities has a negligible effect on the resulting flow regimes when compared to rectangular cavities.
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Miano, Carlo, Massimiliano Gobbi und Giampiero Mastinu. „Multi-Objective Optimization of the Handling Performances of a Road Vehicle: A Fundamental Study on Tire Selection“. Journal of Mechanical Design 126, Nr. 4 (01.07.2004): 687–702. http://dx.doi.org/10.1115/1.1759359.
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The optimization of the handling behavior of road vehicles is dealt with in this paper. Both a linear and a nonlinear model have been considered. A number of analytical solutions to the equations of motion have been derived for the linear model. The objective functions (i.e. performance indices) to be optimized for a steering step input maneuver were the sideslip angle gain, the yaw velocity peak response time, the yaw velocity overshoot and the initial yaw acceleration. The front and rear tire cornering stiffness have been considered as the design variables to be optimized. The derived optimal solutions can be used during preliminary design for the definition of the best vehicle handling performance. The tire cornering stiffness of a number of actual road vehicles comply with the corresponding values coming from the optimization process proposed in the paper.
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Aw, S. T., G. M. Halmagyi, R. A. Black, I. S. Curthoys, R. A. Yavor und M. J. Todd. „Head impulses reveal loss of individual semicircular canal function“. Journal of Vestibular Research 9, Nr. 3 (01.06.1999): 173–80. http://dx.doi.org/10.3233/ves-1999-9304.
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We studied individual semicircular canal responses in three dimensions to high-acceleration head rotations (“head impulses”) in subjects with known surgical lesions of the semicircular canals, and compared their results to those of normal subjects. We found that vestibular-ocular reflex (VOR) gains at close to peak head velocity in response to yaw, pitch and roll impulses were reliable indicators of semicircular canal function. When compared to normals, lateral canal function showed a 70–80% gain at peak of yaw head velocity during ipsilesional yaw impulses. After the loss of one vertical canal function there was a 30–50% and torsional VOR gain in response to ipsilesional pitch and roll impulses respectively. Bilateral deficits in anterior or posterior canal function resulted in a 80–90% impulses, while the loss of ipsilateral anterior and posterior canal functions will result in a 80–90% ipsilesional roll impulses. Three-dimensional vector analysis and animation of the VOR responses in a unilateral vestibular deafferented subject to yaw, pitch and roll impulses further demonstrated the deficits in magnitude and direction of the VOR responses following the loss of unilateral lateral, anterior and posterior canal functions.
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Žuraulis, Vidas, und Edgar Sokolovskij. „Vehicle Velocity Relation to Slipping Trajectory Change: An Option for Traffic Accident Reconstruction“. PROMET - Traffic&Transportation 30, Nr. 4 (03.07.2018): 395–406. http://dx.doi.org/10.7307/ptt.v30i4.2720.
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In this paper, the relation of the velocity of a vehicle in the slip mode to the parameters of the tire marks on the road surface is examined. During traffic accident reconstructions, the initial velocity of a sideslipping vehicle is established according to the tire mark trajectory radius, and calculations highly depend on the directly measured parameters of the tire marks, in particular cases known as yaw marks. In this work, a developed and experimentally validated 14-degree-of-freedom mathematical model of a vehicle is used for an investigation of the relation between velocity and trajectories. The dependence of initial vehicle velocity on tire yaw mark length and trajectory radius was found as a characteristic relation. Hence, after approximation of the permanent slipping part by a polynomial, the parameters of the latter were related to vehicle velocity. The dependences were established by specific experimental tests and computer-aided simulation of the developed model.
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Yang, Zan, Wang Hai-fu, Zheng Yuan-feng und Yu Qing-bo. „Damage Effects of Fluid filled Submunitions by High Velocity Projectile Impact“. Defence Science Journal 70, Nr. 1 (10.02.2020): 47–53. http://dx.doi.org/10.14429/dsj.70.12974.
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A series of tests investigating the damage effects of fluid-filled submunitions by high velocity projectile impact were conducted. An analytical model is presented, in which the yaw angle of the projectile was taken into account. Based on the analytical model, the influence of the strike angle, hit-point offset distance and projectile length to diameter ratio on submunition damage ratio were predicted. The analytical results showed a good agreement with the experiments. The submunition damage ratio strongly depends on the hit-point offset distance, showing a significant decrease with increasing hit-point offset distance. For large hit-point offset distance, increasing the length to diameter ratio of the projectile will effectively improve the submunition damage ratio. There is an appropriate yaw angle of the projectile in which the submunition damage ratio will be maximal.
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Lewis, Richard F., Wangsong Gong, Mitchell Ramsey, Lloyd Minor, Richard Boyle und Daniel M. Merfeld. „Vestibular adaptation studied with a prosthetic semicircular canal“. Journal of Vestibular Research 12, Nr. 2-3 (27.06.2003): 87–94. http://dx.doi.org/10.3233/ves-2003-122-304.
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We have developed and tested a prosthetic semicircular canal that senses angular head velocity and uses this information to modulate the rate of current pulses applied to the vestibular nerve via a stimulating electrode. In one squirrel monkey, the lateral canals were plugged bilaterally and the prosthesis was secured to the animal's head with the angular velocity sensor parallel to the axis of the lateral canals. In the first experiment, the stimulating electrode was placed near the ampullary nerve of one lateral canal. Over a period of two weeks, the gain of the horizontal VOR during yaw axis rotation gradually increased, although the response magnitude remained relatively small. In the second experiment, the stimulating electrode was placed near the ampullary nerve of the posterior canal, but the orientation of the velocity sensor remained parallel to the axis of the lateral canals. Over a one-week period, the axis of the VOR response gradually shifted towards alignment with the (yaw) axis of head rotation. Chronic patterned stimulation of the eighth nerve can therefore provide adequate information to the brain to generate a measurable VOR response, and this can occur even if the prosthetic yaw rotation cue is provided via a branch of the VIIIth nerve that doesn't normally carry yaw rotational cues. The results provided by this pilot study suggest that it may be feasible to study central adaptation by chronically modifying the afferent vestibular cue with a prosthetic semicircular canal.
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Ueno, Mami, Rock Santerre und Alfred Kleusberg. „Direct Determination of Angular Velocity Using GPS“. Journal of Navigation 53, Nr. 2 (Mai 2000): 371–79. http://dx.doi.org/10.1017/s0373463300008900.
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Controlling a ship in a berthing operation is carried out mainly by the change of state, such as velocity and yaw rate (turn rate), although the value of the change of state is very small at berthing. Very high precision is, therefore, required to determine the velocity and angular velocity. A sensor that has an accuracy of ±0.02°/s (1 σ) is sought for determination of turn rate in a berthing system. Three-dimensional angular velocity can directly be determined, with 2 independent baselines of 3 GPS antennas, using instantaneous Doppler measurements or phase rate (temporal difference of phase) observations. This paper discusses the mathematical model for direct determination of angular velocity using GPS, and the comparison of the results of the angular velocity determination using the Doppler and phase rate. The precision of angular velocity determination is estimated using temporal difference of the attitude sensors (TSS and gyrocompass) on board a hydrographic sounding ship. The RMS values of the difference of yaw rate determination between the two systems were: ±0.16°/s using phase rate and ±0.31°/s using Doppler measurements with the separation of onboard antennas of ca. 1·34 m. 10 m baselines could satisfy the sensor requirements for angular velocity determination during berthing maneuvers.
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Aw, S. T., T. Haslwanter, G. M. Halmagyi, I. S. Curthoys, R. A. Yavor und M. J. Todd. „Three-dimensional vector analysis of the human vestibuloocular reflex in response to high-acceleration head rotations. I. Responses in normal subjects“. Journal of Neurophysiology 76, Nr. 6 (01.12.1996): 4009–20. http://dx.doi.org/10.1152/jn.1996.76.6.4009.
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1. The kinematics of the human angular vestibuloocular reflex (VOR) in three dimensions was investigated in 12 normal subjects during high-acceleration head rotations (head “impulses”). A head impulse is a passive, unpredictable, high-acceleration (3,000–4,000 degrees/s2) head rotation of approximately 10–20 degrees in roll, pitch, or yaw, delivered with the subject in the upright position and focusing on a fixation target. Head and eye rotations were measured with dual search coils and expressed as rotation vectors. The first of these two papers describes a vector analysis of the three-dimensional input-output kinematics of the VOR as two indexes in the time domain: magnitude and direction. 2. Magnitude is expressed as speed gain (G) and direction as misalignment angle (delta). G is defined as the ratio of eye velocity magnitude (eye speed) to head velocity magnitude (head speed). delta is defined as the instantaneous angle by which the eye rotation axis deviates from perfect alignment with the head rotation axis in three dimensions. When the eye rotation axis aligns perfectly with the head rotation axis and when eye velocity is in a direction opposite to head velocity, delta = 0. The orientation of misalignment between the head and the eye rotation axes is characterized by two spatial misalignment angles, which are the projections of delta onto two orthogonal coordinate planes that intersect at the head rotation axis. 3. Time series of G were calculated for head impulses in roll, pitch, and yaw. At 80 ms after the onset of an impulse (i.e., near peak head velocity), values of G were 0.72 +/- 0.07 (counterclockwise) and 0.75 +/- 0.07 (clockwise) for roll impulses, 0.97 +/- 0.05 (up) and 1.10 +/- 0.09 (down) for pitch impulses, and 0.95 +/- 0.06 (right) and 1.01 +/- 0.07 (left) for yaw impulses (mean +/- 95% confidence intervals). 4. The eye rotation axis was well aligned with head rotation axis during roll, pitch, and yaw impulses: delta remained almost constant at approximately 5–10 degrees, so that the spatial misalignment angles were < or = 5 degrees. delta was 9.6 +/- 3.1 (counterclockwise) and 9.0 +/- 2.6 (clockwise) for roll impulses, 5.7 +/- 1.6 (up) and 6.1 +/- 1.9 (down) for pitch impulses, and 6.2 +/- 2.2 (right) and 7.9 +/- 1.5 (left) for yaw impulses (mean +/- 95% confidence intervals). 5. VOR gain (gamma) is the product of G and cos(delta). Because delta is small in normal subjects, gamma is not significantly different from G. At 80 ms after the onset of an impulse, gamma was 0.70 +/- 0.08 (counterclockwise) and 0.74 +/- 0.07 (clockwise) for roll impulses, 0.97 +/- 0.05 (up) and 1.09 +/- 0.09 (down) for pitch impulses, and 0.94 +/- 0.06 (right) and 1.00 +/- 0.07 (left) for yaw impulses (mean +/- 95% confidence intervals). 6. VOR latencies, estimated with a latency shift method, were 10.3 +/- 1.9 (SD) ms for roll impulses, 7.6 +/- 2.8 (SD) ms for pitch impulses, and 7.5 +/- 2.9 (SD) ms for yaw impulses. 7. We conclude that the normal VOR produces eye rotations that are almost perfectly compensatory in direction as well as in speed, but only during yaw and pitch impulses. During roll impulses, eye rotations are well aligned in direction, but are approximately 30% slower in speed.
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Tian, Jie, Ya Qin Wang und Ning Chen. „Research on Vehicle Stability Based on DYC and AFS Integrated Controller“. Applied Mechanics and Materials 278-280 (Januar 2013): 1510–15. http://dx.doi.org/10.4028/www.scientific.net/amm.278-280.1510.
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A new vehicle stability control method integrated direct yaw moment control (DYC) with active front wheel steering (AFS) was proposed. On the basis of the vehicle nonlinear model, vehicle stable domain was determined by the phase plane of sideslip angle and sideslip angular velocity. When the vehicle was outside the stable domain, DYC was firstly used to produce direct yaw moment, which can make vehicle inside the stable domain. Then AFS sliding mode control was used to make the sideslip angle and yaw rate track the reference vehicle model. The simulation results show that the integrated controller improves vehicle stability more effectively than using the AFS controller alone.
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Altork, Basim, und Hakan Yazici. „Robust static output feedback H∞-controller design for three degree of freedom integrated bus lateral, yaw, roll dynamics model“. Transactions of the Institute of Measurement and Control 41, Nr. 16 (20.08.2019): 4545–68. http://dx.doi.org/10.1177/0142331219863875.
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In this paper, a three-degree-of freedom (3 DOF) integrated vehicle lateral, yaw, roll dynamics model with optimal control design have been proposed to improve the bus lateral stability and handling performance. First, a 3 DOF vehicle model for a passenger bus is introduced. The 3 DOF model dynamics include the vehicle steering wheel angle, forward speed, yaw motion, sideslip angle, lateral acceleration and the rolling motion. Then, the presented 3 DOF model is used to design the robust static output feedback [Formula: see text] controller for both nominal system and uncertain system. The proposed controller is designed to improve the bus lateral stability and handling performance by controlling the yaw rate during normal driving and maneuvers. For the robust static output feedback [Formula: see text] controller, the norm bounded uncertainty is considered to simulate the variation of vehicle forward velocity uncertainty. The robust controller is designed to check the lateral stability of the bus at different forward velocity and at different velocity uncertainty. The controllers are synthesized within the [Formula: see text] control approach and the controllers’ design conditions are given within the Linear Matrix Inequalities (LMIs) framework. Numerical simulations have been carried out to demonstrate the effectiveness of the proposed controllers. The obtained simulation results show that the designed nominal and robust controllers enhance the lateral stability of the bus by reducing the amplitude of the yaw rate, lateral acceleration and rolling motion. Hence, the improvements in bus lateral stability and handling performance are achieved.
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Balaban, Carey D., David M. McGee, Jianxun Zhou und Charles A. Scudder. „Responses of Primate Caudal Parabrachial Nucleus and Kölliker-Fuse Nucleus Neurons to Whole Body Rotation“. Journal of Neurophysiology 88, Nr. 6 (01.12.2002): 3175–93. http://dx.doi.org/10.1152/jn.00499.2002.
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The caudal aspect of the parabrachial (PBN) and Kölliker-Fuse (KF) nuclei receive vestibular nuclear and visceral afferent information and are connected reciprocally with the spinal cord, hypothalamus, amygdala, and limbic cortex. Hence, they may be important sites of vestibulo-visceral integration, particularly for the development of affective responses to gravitoinertial challenges. Extracellular recordings were made from caudal PBN cells in three alert, adult female Macaca nemestrina through an implanted chamber. Sinusoidal and position trapezoid angular whole body rotation was delivered in yaw, roll, pitch, and vertical semicircular canal planes. Sites were confirmed histologically. Units that responded during rotation were located in lateral and medial PBN and KF caudal to the trochlear nerve at sites that were confirmed anatomically to receive superior vestibular nucleus afferents. Responses to whole-body angular rotation were modeled as a sum of three signals: angular velocity, a leaky integration of angular velocity, and vertical position. All neurons displayed angular velocity and integrated angular velocity sensitivity, but only 60% of the neurons were position-sensitive. These responses to vertical rotation could display symmetric, asymmetric, or fully rectified cosinusoidal spatial tuning about a best orientation in different cells. The spatial properties of velocity and integrated velocity and position responses were independent for all position-sensitive neurons; the angular velocity and integrated angular velocity signals showed independent spatial tuning in the position-insensitive neurons. Individual units showed one of three different orientations of their excitatory axis of velocity rotation sensitivity: vertical-plane-only responses, positive elevation responses (vertical plane plus ipsilateral yaw), and negative elevation axis responses (vertical plane plus negative yaw). The interactions between the velocity and integrated velocity components also produced variations in the temporal pattern of responses as a function of rotation direction. These findings are consistent with the hypothesis that a vestibulorecipient region of the PBN and KF integrates signals from the vestibular nuclei and relay information about changes in whole-body orientation to pathways that produce homeostatic and affective responses.
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Chen, Jun, und Xiao Jun Ye. „Numerical Simulation of the Kinetic Energy Projectile Deflected by Targets Moving along Transverse Direction“. Advanced Materials Research 989-994 (Juli 2014): 2787–90. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.2787.
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When the kinetic energy projectile into concrete target movement, angle of attack can affect the penetration process of ballistic performance, resulting deflection effect, thus affecting the penetration depth. For the analysis of kinetic energy projectile penetrating the lateral movement of the target deflection model, using the finite element simulation software for lateral movement of the target missile penetrates the process of numerical simulation. The results showed that: rigid lateral movement of the target missile and projectile kinetic energy projectile velocity has some deflection effect. Playing the role of the kinetic energy of the lateral movement of the target, the missile body yaw angular velocity increases and then decreases after the first, but not so obvious kinetic energy projectile yaw.
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Li, Yu Guang, Chang Fei Liang und Shu Fen Wang. „Study of Vehicle Handling Stability Based on MATLAB“. Applied Mechanics and Materials 602-605 (August 2014): 489–92. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.489.
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In this paper, the sideslip angle and yaw velocity as parameters are presented to describing the motion state of the motion state of the vehicle, in which two DOF(degree of freedom) vehicle model is used as the reference model. And car speed is considered as the system step input to building a three DOF vehicle model based on H.B. Pacejka’s tire model. Meanwhile, the sideslip angle and the yaw velocity are taken as the system outputs. And achieve simulated analysis of vehicle handing stability by using Simulink. The results show that the three DOF vehicle model is more accurate in description of transport condition, which provides reference for the study of the vehicle steering stability.
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Madsen, P. H., und G. M. McNerney. „Frequency Domain Modeling of Free Yaw Response of Wind Turbines to Wind Turbulence“. Journal of Solar Energy Engineering 113, Nr. 2 (01.05.1991): 102–11. http://dx.doi.org/10.1115/1.2929953.
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A frequency domain method has been developed in order to study the yaw dynamics and its effect on energy capture under various turbulence regimes for free yaw wind turbines. It is assumed that the primary forcing of the dynamic yaw originates from the variations from wind turbulence in the average wind direction and the horizontal gradient of the wind speed across the rotor. The horizontal components of the turbulence velocity are modeled as random processes with spectral characteristics calibrated from measurements. The corresponding statistics of the wind direction and the gradient are derived and used as input for an equivalent linear model of the system dynamics. The parameters in the simplified system model are identified from the results of a numerical test of a comprehensive yaw response and energy capture simulation model, developed at U. S. Windpower. The yaw response of the USW Model 56-100 machine to turbulence has been analyzed for a number of wind conditions and compared to test results with satisfactory agreement. The analysis shows that the effect on the yaw error from the horizontal wind gradient is twice the effect from wind direction changes.
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Bertolini, G., S. Ramat, J. Laurens, C. J. Bockisch, S. Marti, D. Straumann und A. Palla. „Velocity Storage Contribution to Vestibular Self-Motion Perception in Healthy Human Subjects“. Journal of Neurophysiology 105, Nr. 1 (Januar 2011): 209–23. http://dx.doi.org/10.1152/jn.00154.2010.
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Self-motion perception after a sudden stop from a sustained rotation in darkness lasts approximately as long as reflexive eye movements. We hypothesized that, after an angular velocity step, self-motion perception and reflexive eye movements are driven by the same vestibular pathways. In 16 healthy subjects (25–71 years of age), perceived rotational velocity (PRV) and the vestibulo-ocular reflex (rVOR) after sudden decelerations (90°/s2) from constant-velocity (90°/s) earth-vertical axis rotations were simultaneously measured (PRV reported by hand-lever turning; rVOR recorded by search coils). Subjects were upright (yaw) or 90° left-ear-down (pitch). After both yaw and pitch decelerations, PRV rose rapidly and showed a plateau before decaying. In contrast, slow-phase eye velocity (SPV) decayed immediately after the initial increase. SPV and PRV were fitted with the sum of two exponentials: one time constant accounting for the semicircular canal (SCC) dynamics and one time constant accounting for a central process, known as velocity storage mechanism (VSM). Parameters were constrained by requiring equal SCC time constant and VSM time constant for SPV and PRV. The gains weighting the two exponential functions were free to change. SPV were accurately fitted (variance-accounted-for: 0.85 ± 0.10) and PRV (variance-accounted-for: 0.86 ± 0.07), showing that SPV and PRV curve differences can be explained by a greater relative weight of VSM in PRV compared with SPV (twofold for yaw, threefold for pitch). These results support our hypothesis that self-motion perception after angular velocity steps is be driven by the same central vestibular processes as reflexive eye movements and that no additional mechanisms are required to explain the perceptual dynamics.
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Haichao, Li, und Man Yiyun. „Computation of Satellite Yaw Angular Velocity for Relative Radiometric Calibration“. Signal Processing Research 4 (2015): 42. http://dx.doi.org/10.14355/spr.2015.04.007.
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Liu, Qiyong, Ying Luo, Qun Zhang, Wen Hong und Tat Yeo. „Precision Downward-Looking 3D Synthetic Aperture Radar Imaging with Sparse Linear Array and Platform Motion Parameters Estimation“. Remote Sensing 10, Nr. 12 (05.12.2018): 1957. http://dx.doi.org/10.3390/rs10121957.
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The downward-looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3D SAR) has attracted a great deal of attention, due to the ability to obtain three-dimensional (3D) images. However, if the velocity and the yaw rate of the platform are not measured with enough accuracy, the azimuth signal cannot be compressed and then the 3D image of the scene cannot be obtained. In this paper, we propose a method for platform motion parameter estimation, and downward-looking 3D SAR imaging. A DLSLA 3D SAR imaging model including yaw rate was established. We then calculated the Doppler frequency modulation, which is related to the cross-track coordinates rather than the azimuth coordinates. Thus, the cross-track signal reconstruction was realized. Furthermore, based on the minimum entropy criterion (MEC), the velocity and yaw rate of the platform were accurately estimated, and the azimuth signal compression was also realized. Moreover, a deformation correction procedure was designed to improve the quality of the image. Simulation results were given to demonstrate the validity of the proposed method.
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Li, Xian. „Lateral stability control of distributed driven electric vehicle based on sliding mode control“. E3S Web of Conferences 252 (2021): 01044. http://dx.doi.org/10.1051/e3sconf/202125201044.
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Aiming at the lateral stability control problem of distributed driven electric vehicles under high speed steering condition, a hierarchical control algorithm of direct yaw moment is designed. The upper control takes the 2-DOF vehicle model as the reference model and uses the sliding mode control to obtain the required yaw moment by tracking the desired yaw velocity and the desired vehicle side-slip angle. The lower control optimizes the distribution of four wheel torque with the minimum tire utilization rate. Finally, Carsim/Simulink was used for model building and co-simulation, and the control effect of PID algorithm was compared. The results show the hierarchical control algorithm achieves the expected goal of improving vehicle lateral stability.
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Dettki, F. „A test method for the quantification of on-centre handling with respect to cross-wind“. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 216, Nr. 4 (01.04.2002): 259–66. http://dx.doi.org/10.1243/0954407021529093.
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During the development process of a new passenger car chassis, certain aspects of the driving dynamics concerning comfort and handling receive particular attention. During this process it is crucial to maintain basic characteristics. One of these basic characteristics is the straight-ahead stability. It is also important that the driver can feel this straight-ahead stability through the steering wheel. With the wording ‘on-centre handling’, both aspects are addressed: the objective straight-ahead stability and the subjective feeling for very small steering wheel movements. This article presents a proposal for the objective description of on-centre handling. A new method is introduced to allow the calculation of characteristic values for the straight-ahead stability without any driver influence. The principle of this new method consists of a comparison between the measured and the calculated yaw velocities. The calculated yaw velocity results from a modified single-track model. The yaw velocity error is the result of the difference between the calculated and measured yaw velocities. After this error is calculated it will be plotted versus the measured disturbance variables (wind, lateral inclination). The vehicle response is more sensitive to the disturbance for a larger gradient of this graph. For the complete description of on-centre handling, it is necessary to characterize the steering feel. Characteristic values are introduced to describe the steering feel and the corresponding vehicle reaction.
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Divaret, L., O. Cadot, P. Moussou und O. Doaré. „Normal forces exerted upon a long cylinder oscillating in an axial flow“. Journal of Fluid Mechanics 752 (11.07.2014): 649–69. http://dx.doi.org/10.1017/jfm.2014.342.
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AbstractThis work aims to improve understanding of the damping induced by an axial flow on a rigid cylinder undergoing small lateral oscillations within the framework of the quasistatic assumption. The study focuses on the normal force exerted on the cylinder for a Reynolds number of $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\mathit{Re}=24\, 000$ (based on the cylinder diameter and axial flow velocity). Both dynamic and static approaches are investigated. With the static approach, fluid forces, pressure distributions and velocity fields are measured for different yaw angles and cylinder lengths in a wind tunnel. It is found that for yaw angles smaller than $5{^\circ }$, the normal force varies linearly with the angle and is fully dominated by its lift component. The lift originates from the high pressure coefficient at the front of the cylinder, which is found to depend linearly on the angle, and from a base pressure coefficient that remains close to zero independent of the yaw angle. At the base, a flow deficit and two counter-rotating vortices are observed. A numerical simulation using a $k\mbox{--}\omega $ shear stress transport turbulence model confirms the static experimental results. A dynamic experiment conducted in a water tunnel brings out damping-rate values during free oscillations of the cylinder. As expected from the linear dependence of the normal force on the yaw angle observed with the static approach, the damping rate increases linearly with the axial flow velocity. Satisfactory agreement is found between the two approaches.
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Nugroho, Gesang, und Zahari Taha. „Helicopter Motion Control Using Model-Based Sliding Mode Controller“. Journal of Advanced Computational Intelligence and Intelligent Informatics 12, Nr. 4 (20.07.2008): 342–47. http://dx.doi.org/10.20965/jaciii.2008.p0342.
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This paper describes a model-based controller design for helicopter using the sliding mode approach. The controller design assumes that only measured output are available and uses sliding mode observer to estimate all states of the system. The estimated states are then used to construct a model reference sliding mode control law. Simulation shows good performance for lateral velocity, longitudinal velocity, vertical velocity and yaw rate control.
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Wang, Huan, Xiu Hua Gao, Jian Kai Chen und Chao Wang. „The Impact of Nonlinear of Tire on Multi-Axle Vehicle Steering“. Advanced Materials Research 403-408 (November 2011): 3424–29. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.3424.
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BP neural network model of tire and three degrees of freedom dynamic model of Multi-Axle vehicle were built. According to Zero side slip angle control theory, with the use of MATLAB software, comparative analysis of the step response of the vehicle side slip angle, yaw angle velocity and rolling angle in the driving vehicle with linear and nonlinear tires was done. The results show thatMulti-Axle vehicle with nonlinear tires has obvious affect between side slip angle and yaw angle velocity of the vehicle body. Relative to Multi-Axle vehicle with linear tires, the overshoot of step response increases greatly, and the Steady-State value does not equal to zero; but rolling angle of the vehicle with nonlinear tires has less affected.
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Lu, Shou Lei, Long Zhao und Chang Yun Zhang. „Improved Tercom Based on Fading Factor“. Applied Mechanics and Materials 143-144 (Dezember 2011): 770–74. http://dx.doi.org/10.4028/www.scientific.net/amm.143-144.770.
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In order to solve the problem of the traditional Tercom, which is sensitive to the speed error and yaw angle error, an improved Tercom approach using with fading factor is introduced. The basic idea of this approach is to estimate the navigation position by a novel correlation function. The correlation function is calculated by weighted historical measurements. Experiment results with the real data show that this approach performs better than the traditional Tercom with regard to overcoming velocity error and yaw angle error.
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Patil, Prabhugouda M., Hadapad F. Shankar und Mikhail A. Sheremet. „Nonlinear Mixed Convective Flow over a Moving Yawed Cylinder Driven by Buoyancy“. Mathematics 9, Nr. 11 (01.06.2021): 1275. http://dx.doi.org/10.3390/math9111275.
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The fluid flow over a yawed cylinder is useful in understanding practical significance for undersea applications, for example, managing transference and/or separation of the boundary layer above submerged blocks and in suppressing recirculating bubbles. The present analysis examines nonlinear mixed convection flow past a moving yawed cylinder with diffusion of liquid hydrogen. The coupled nonlinear control relations and the border restrictions pertinent to the present flow problem are nondimensionalized by using nonsimilar reduction. Further, implicit finite difference schemes and Quasilinearization methods are employed to solve the nondimensional governing equations. Impact of several nondimensional parameters of the analysis on the dimensionless velocity, temperature and species concentration patterns and also on Nusselt number, Sherwood number and friction parameter defined at the cylinder shell is analyzed through numerical results presented in various graphs. Velocity profiles can be enhanced, and the coefficients of friction at the surface can be reduced, for increasing values of velocity ratio parameters along chordwise as well as spanwise directions. Species concentration profile is reduced, while the Sherwood number is enhanced, for growth of the Schmidt number and yaw angles. Furthermore, for an increasing value of yaw angle, skin-friction coefficient in chordwise direction diminishes in opposing buoyancy flow case, whereas the results exhibit the opposite trend in assisting buoyancy flow case. Moreover, very importantly, for increasing magnitude of nonlinear convection characteristic, the liquid velocity and surface friction enhance in spanwise direction. Further, for increasing magnitude of combined convection characteristics, velocity profiles and coefficient of friction at the surface enhance in both spanwise and chordwise directions. Moreover, we have observed that there is no deviation for zero yaw angle in Nusselt number and Sherwood number.
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Kushiro, Keisuke, Mingjia Dai, Mikhail Kunin, Sergei B. Yakushin, Bernard Cohen und Theodore Raphan. „Compensatory and Orienting Eye Movements Induced By Off-Vertical Axis Rotation (OVAR) in Monkeys“. Journal of Neurophysiology 88, Nr. 5 (01.11.2002): 2445–62. http://dx.doi.org/10.1152/jn.00197.222.
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Nystagmus induced by off-vertical axis rotation (OVAR) about a head yaw axis is composed of a yaw bias velocity and modulations in eye position and velocity as the head changes orientation relative to gravity. The bias velocity is dependent on the tilt of the rotational axis relative to gravity and angular head velocity. For axis tilts <15°, bias velocities increased monotonically with increases in the magnitude of the projected gravity vector onto the horizontal plane of the head. For tilts of 15–90°, bias velocity was independent of tilt angle, increasing linearly as a function of head velocity with gains of 0.7–0.8, up to the saturation level of velocity storage. Asymmetries in OVAR bias velocity and asymmetries in the dominant time constant of the angular vestibuloocular reflex (aVOR) covaried and both were reduced by administration of baclofen, a GABAB agonist. Modulations in pitch and roll eye positions were in phase with nose-down and side-down head positions, respectively. Changes in roll eye position were produced mainly by slow movements, whereas vertical eye position changes were characterized by slow eye movements and saccades. Oscillations in vertical and roll eye velocities led their respective position changes by ≈90°, close to an ideal differentiation, suggesting that these modulations were due to activation of the orienting component of the linear vestibuloocular reflex (lVOR). The beating field of the horizontal nystagmus shifted the eyes 6.3°/ g toward gravity in side down position, similar to the deviations observed during static roll tilt (7.0°/ g). This demonstrates that the eyes also orient to gravity in yaw. Phases of horizontal eye velocity clustered ∼180° relative to the modulation in beating field and were not simply differentiations of changes in eye position. Contributions of orientating and compensatory components of the lVOR to the modulation of eye position and velocity were modeled using three components: a novel direct otolith-oculomotor orientation, orientation-based velocity modulation, and changes in velocity storage time constants with head position re gravity. Time constants were obtained from optokinetic after-nystagmus, a direct representation of velocity storage. When the orienting lVOR was combined with models of the compensatory lVOR and velocity estimator from sequential otolith activation to generate the bias component, the model accurately predicted eye position and velocity in three dimensions. These data support the postulates that OVAR generates compensatory eye velocity through activation of velocity storage and that oscillatory components arise predominantly through lVOR orientation mechanisms.
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Wang, Zeng Yu, Yuan Xu und Qing Hua Li. „Indoor Wireless Positioning Utilizing WSN and Machine Vision“. Applied Mechanics and Materials 325-326 (Juni 2013): 1041–44. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.1041.
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It is a challenging issue to develop optimal real-time target tracking methods for automobile in the small areas such as urban and indoor environments. In order to get comprehensive navigation information, a target tracking system utilizing ultrasound and machine vision is proposed. In this system, the position, velocity and the yaw in the relative coordinate are used as the state variables, the ultrasound is used to measure the distance between the reference node and the blind node, and the yaw of the automobile is measured by the machine vision. Then, the extended Kalman filter is used to fuse the information measured from local estimators in the proposed method. Simulations show that the position error of the proposed approach is about 0.2m and the velocity error of the proposed approach is about 0.1 m/s.
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Dong, Guang Ming, Jin Chen und Nong Zhang. „Study on the Time Lag between Steering Input and Vehicle Lateral Acceleration Response under Different Key Vehicle Parameters“. Applied Mechanics and Materials 226-228 (November 2012): 681–84. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.681.
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A passively suspended road vehicle rolls outwards under the influence of lateral acceleration when cornering, which is very dangerous under large lateral acceleration. In this paper, time lag between steering input and vehicle lateral acceleration response is systematically studied to implement the active roll control algorithm from the viewpoint of vehicle system dynamics. A 3 DOF yaw-roll vehicle model is established based on vehicle lateral, roll and yaw dynamics. Vehicle parameters of a 1997 Jeep Cherokee is used for parametric study, where the influences of vehicle velocity, steering frequency, mass, length, roll, yaw moment of inertia, position of vehicle centre of gravity, and tyre cornering stiffness are studied via numerical simulation. The analysis results will help improve the real time rollover warning/control algorithm design for vehicle safety.
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Raksincharoensak, Pongsathorn, Sato Daisuke und Mathias Lidberg. „Direct Yaw Moment Control for Enhancing Handling Quality of Lightweight Electric Vehicles with Large Load-To-Curb Weight Ratio“. Applied Sciences 9, Nr. 6 (19.03.2019): 1151. http://dx.doi.org/10.3390/app9061151.
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In this paper a vehicle dynamics control system is designed to compensate the change in vehicle handling dynamics of lightweight vehicles due to variation in loading conditions and the effectiveness of the proposed design is verified by simulations and an experimental study using a fixed-base driving simulator. Considering the electrification of future mobility, the target vehicle of this research is a lightweight vehicle equipped with in-wheel motors that can generate an additional direct yaw moment by transverse distribution of traction forces to control vehicle yawing as well as side slip motions. Previously, the change in vehicle handling dynamics for various loading conditions have been analyzed by using a linear two-wheel vehicle model in planar motion and a control law of the DYC system based on feed-forward of front steering angular velocity and feedback of vehicle yaw rate. The feed-forward controller is derived based on the model following control with approximation of the vehicle dynamics to 1st-order transfer function. To make the determination of the yaw rate feedback gain model-based and adaptable to various vehicle velocity conditions, this paper selects a method where the yaw rate feedback gain in the DYC system is determined in a way that the steady-state yaw rate gain of the controlled loaded vehicle matches the gain of the unloaded vehicle. The DYC system is simulated in a single lane change maneuver to confirm the improved responsiveness of the vehicle while simulations of a double-lane change maneuver with a driver steering model confirms the effectiveness of the DYC system to support tracking control. Finally, the effectiveness of the proposed DYC system is also verified in an experimental study with ten human drivers using a fix-based driving simulator.
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Clément, Gilles, Scott J. Wood, Millard F. Reschke, Alain Berthoz und Makoto Igarashi. „Yaw and pitch visual-vestibular interaction in weightlessness“. Journal of Vestibular Research 9, Nr. 3 (01.06.1999): 207–20. http://dx.doi.org/10.3233/ves-1999-9308.
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Both yaw and pitch visual-vestibular interactions at two separate frequencies of chair rotation (0.2 and 0.8 Hz) in combination with a single velocity of optokinetic stimulus ( 36 ∘ /s) were used to investigate the effects of sustained weightlessness on neural strategies adopted by astronaut subjects to cope with the stimulus rearrangement of spaceflight. Pitch and yaw oscillation in darkness at 0.2 and 0.8 Hz without optokinetic stimulation, and constant velocity linear optokinetic stimulation at 18, 36, and 54 ∘ /s presented relative to the head with the subject stationary, were used as controls for the visual-vestibular interactions. The results following 8 days of space flight showed no significant changes in: (1) either the horizontal and vertical vestibulo-ocular reflex (VOR) gain, phase, or bias; (2) the yaw visual-vestibular response (VVR); or (3) the horizontal or vertical optokinetic (OKN) slow phase velocity (SPV). However, significant changes were observed: (1) when during pitch VVR at 0.2 Hz late inflight, the contribution of the optokinetic input to the combined oculomotor response was smaller than during the stationary OKN SPV measurements, followed by an increased contribution during the immediate postflight testing; and (2) when during pitch VVR at 0.8 Hz, the component of the combined oculomotor response due to the underlying vertical VOR was more efficiently suppressed early inflight and less suppressed immediately postflight compared with preflight observations. The larger OKN response during pitch VVR at 0.2 Hz and the better suppression of VOR during pitch VVR at 0.8 Hz postflight are presumably due to the increased role of vision early inflight and immediately after spaceflight, as previously observed in various studies. These results suggest that the subjects adopted a neural strategy to structure their spatial orientation in weightlessness by reweighting visual, otolith, and perhaps tactile/somatic signals.