Dissertations / Theses on the topic 'Braking torque'

Dither control is a method of introducing high frequency control efforts into a system to suppress a lower frequency disturbance. Dither control is an effective means of suppressing automotive brake squeal. Brake squeal is a problem that has plagued the automotive industry for years. In fact many makers of materials for brake pads spend up to 50% of their engineering budgets on noise, vibration and harshness issues. A normal dither signal may be introduced to an automotive braking system by placing a piezoceramic stack actuator in the piston of a floating caliper brake. Many theoretical models indicate a reduction in the braking torque due to the dither signal. Under the assumption of Hertzian contact stiffness the loss in braking torque is due to lowering of the average normal force. There are also theories that the dither signal eliminates the stick-slip oscillation causing an effective decrease in the friction force. Yet another theory indicates that the effective contact area is reduced, lowering the mean coefficient of friction. It is not apparent whether any of these models accurately portrays the interaction of the brake pads and rotor.

The limitations of current simulation packages in addressing the true longitudinal behaviour of railway bogie dynamics during braking/traction has prompted the development of a Rail Bogie Dynamics (RBD) program in this thesis. The RBD program offers novel features for the calculation of the speed profile as a function of the brake torque as well as explicitly determining wheelset angular velocity. With such capability, the speed profile is no longer treated as an input calculated as a priori as required by most of the current simulation systems. The RBD program has been developed using a formulation that includes the wheelset pitch degree of freedom explicitly with a coordinate reference system that is fixed in space and time. The formulation has made the simulation of the bogie dynamics during braking/traction possible in a natural way using the brake/traction torque as the input and the resulting speed profile as the output without any need for working out the speed profile as a priori. Consequently, severe dynamics during braking such as the wheelset skid and the onset of wheel climb derailment can be modelled and critical parameters investigated using the RBD program. The RBD program has been validated, where possible, through a series of simulations using a commercial software package (VAMPIRE). For cases which cannot be simulated by VAMPIRE such as the wheelset skid, a novel experimental program has been designed and commissioned in the Heavy Testing Laboratory of the Central Queensland University as reported in this thesis. One of the possible applications of the RBD program in examining the effect of asymmetric brake shoe force in bogies equipped with one-side push brake shoe arrangement is illustrated in this thesis. It is believed that the model and RBD program will have significant benefit in understanding the true longitudinal behaviour of wagons in suburban passenger trains that operate under braking/ traction torques for most of their travel. Similar studies will also be useful to freight train wagon dynamics during entry and exit of speed restriction zones and tight curves.

The object of this work is design braking device with high repeatability and reproducibility that is used to analyse the measurement system. I developed this work in cooperation with TRW-DAS Dačice a.s. At the beginning, I made a search of the chassis system, testing of ball joints and steering. Furthermore, I made search of the MSA and the types of braking devices. The rest of the work is focused on the design and the thermal analysis of braking device. Then there are the actual test.

This master thesis report has studied several methods to improve the energy consumption of an electric vehicle equipped with two permanent magnet synchronous motors. Two driving torque distribution maps are developed based on efficiency map and load transfer, respectively. The drive torque distribution map based on the efficiency map shows up to 8.94% energy saving. Two regenerative braking strategies are designed and compared. Both strategies have pure regenerative brake at low decelerations and it is controlled by a modified acceleration pedal map. Strategy 1 does not add more regenerative braking when the brake pedal is pressed thus it is simpler while strategy 2 can blend in more motor torque. Rear axle steering is also studied in terms of contribution to energy consumption and an LQR controller is developed to control the vehicle with rear axle steering.
Denna rapport avhandlar ett examensarbete där flera metoder har studerats för att förbättra energikonsumptionen för ett elektriskt fordon med två permanentmagnetsynkrona motorer. Två fördelningskartor för drivande moment är framtagna baserat på effektivitetskartor och lastöverföring. Fördelningskartorna för drivande moment som är baserat på effektivitet visar upp till 8,94% energiminskning. Två olika regenerativa bromsstrategier är framtagna och jämförda. Båda strategierna har ren regeneration vid låga decelerationer och är reglerat genom modifierat gaspedalsmappning. Strategi 1 ger inte mer regeneration när bromspedalen trycks ned och är då enklare medans strategi 2 kan blanda in mer vridmoment från elmotorn. Bakaxelstyrning är också studerat i termer av dess bidrag till energikonsumption samt en LQR regulator är utvecklad för reglering av fordonets bakaxelstyrning.

U doktorskoj disertaciji razmatra se unapređenje konstrukcije magnetoreološke disk kočnice sa ciljem povećanja vrednosti ukupnog kočnog momenta. Radi potpunog razumevanja međusobnog odnosa materijala i magnetskog polja na prvom mestu je izvršeno utvrđivanje magnetskih svojstava materijala. Unapređenje konstrukcije je izvršeno kroz više iteracija i prototipova. Merenje vrednosti ukupnog kočnog momenta je podeljeno na merenje više njegovih komponenti pri različitim vrednostima broja obrtaja i upravljačke struje namotaja.
In this thesis magnetorheological disk brake construction improvement is considered, with the goal to increase the overall braking torque value. For purposes of better understanding of material to magnetic field relationship, series of magnetic field testing were conducted. Construction improvement has been carried out through several iterations and different prototypes. Overall braking torque value measurements have been divided into several component measurements, utilizing different rotational speeds and coil control currents.

This thesis is dealing with a detailed analysis of electromechanical brake used in emergency situations to stop the electric motor. Environmental influences, bad material proposal or bad design parameters can significantly limit the behaviour of a brake. The thesis presents several approaches to avoid these limitations, to limit the reaction time and achieve better results. The attached programs can be used either for innovation, or for the new brake design based on the entry requirements.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.05 «Піднімально-транспортні машини». – Тернопільський національний технічний університет імені Івана Пулюя, Тернопіль, 2021. У дисертації на підставі сукупності узагальнених наукових результатів вирішено нове актуальне завдання підвищення технологічної ефективності процесу роботи гвинтових транспортних механізмів шляхом удосконалення конструкції та обґрунтування параметрів інерційної планетарної запобіжної муфти, яку виконано на основі біпланетарного інерційного механізму з рухомою реактивною ланкою. На основі проведених теоретично-експериментальних досліджень розроблено: аналітичні залежності, які дозволяють аналізувати переміщення точки дебалансу та механізму загалом; аналітичні залежності для визначення кінематичних і динамічних параметрів стопового режиму роботи гвинтового конвеєра з інерційною планетарною запобіжною муфтою; емпіричні рівняння, які характеризують зміну гальмівного обертового моменту стопового режиму роботи та коефіцієнта корисної дії передачі обертового моменту. На основі проведених теоретичних і експериментальних досліджень обґрунтовано основні раціональні параметри інерційної планетарної запобіжної муфти гвинтового конвеєра. Максимальний обертовий момент вихідного вала інерційної планетарної запобіжної муфти гвинтового конвеєра у стоповому режимі формується шляхом зростання енергії дебаланса за рахунок збільшення швидкостей обертання дебаланса навколо своєї осі та осі привода імпульсного модуля та змінюється в діапазоні 19,6 … 29,4 Н∙м за відповідного передаточного відношення приводу дебаланса, що дорівнює 2,2. Раціональне функціонування процесу роботи гвинтового конвеєра з метою забезпечення максимального гальмівного обертового моменту вихідного вала при виникненні перевантаження його робочих органів у межах від 20 Н∙м до 42 Н∙м, або початку стопового режиму роботи гвинтового конвеєра досягнуто за наступних параметрів: частота обертання вхідного вала ІПЗМ від 262,5 об/хв до 437,5 об/хв; передаточне відношення приводу верхнього дебалансу від 2,0 до 3,2; передаточне відношення приводу нижнього дебалансу рівне 1,0. Конструктивна новизна технічного рішення захищена патентом України на корисну модель.
The dissertation for obtaining a scientific degree of the Candidate of technical sciences on a specialty 05.05.05 "Lifting and transportation machinery". – Ternopil Ivan Puluj National Technical University, Ternopil, 2021. In the dissertation, on the basis of the set of generalized scientific results, the new actual problem of increasing the technological efficiency of screw transport mechanisms operation process is solved due to design improvement and substantiation of parameters of the inertial planetary safety clutch, which is produced on the basis of the biplanetary inertial mechanism with a mobile reactive link. On the basis of the conducted theoretical and experimental research the following has been developed: analytical dependences which allow to analyse the displacement of the imbalance point and the mechanism in general; analytical dependences for determination of kinematic and dynamic parameters of the operation stop mode of the screw conveyor with inertial planetary safety clutch; empirical equations that characterize the change in braking torque of the stop mode and the torque transmission efficiency. Grounded on the conducted theoretical and experimental research, the optimal parameters of the inertial planetary safety clutch of the screw conveyor are substantiated. The braking safety torque of the output shaft of the screw conveyor inertial planetary safety clutch in the stop mode is formed by means of increasing the imbalance energy due to acceleration of the imbalance rotation around its axis and the drive axis of the pulse module as well as range variation of 19.6 … 29.4 N∙m, when respective gear ratio of the imbalance drive equals to 2.2. Rational functioning of the process of the screw conveyor operation in terms of providing maximum braking torque of the output shaft in case of overload of its working parts in the range from 20 N∙m to 42 N∙m, or the beginning of the stop mode of the screw conveyor, is achieved by the following parameters: input shaft speed is from 262.5 rpm to 437.5 rpm; the gear ratio of the upper imbalance drive is from 2.0 to 3.2 and the lower imbalance drive is equal to 1.0. The annual economic effect achieved by increasing the technological capabilities of the screw conveyor is UAH 12,209.7. The research results were implemented at PJSC "TerA" (Ternopil), LLC "Ukraine" (Ternopil region, Pidvolochysk district) and PP "Ukraine-Agro-2C" (Khmelnytsky region, Chemerivtsi district) in technological lines, respectively, for transportation and dough formation and for transportation of bulk products and goods. Theoretical and practical results of the research were implemented in the educational process of Ternopil Ivan Puluj National Technical University during teaching the subject "Drives of Machines and Machine Complexes". The constructive novelty of the technical solution is protected by a patent of Ukraine for a utility model.

Este trabalho foi desenvolvido com o objetivo de estudar a aplicação, para sistema de frenagem veicular, de uma máquina elétrica sem escovas, de armadura toroidal, e fluxo magnético axial produzido por ímãs permanentes de terras raras, a chamada máquina Torus. A máquina foi construída no LMEAE e estudada inicialmente como motor em outro trabalho. Mas, para que se possa avaliar seu funcionamento em sistema de frenagem, o foco é do ponto de vista da máquina como gerador. São realizados testes dinâmicos e estáticos experimentalmente e modelo numérico pelo método dos elementos finitos com um formato de ímãs permanentes de seção setorial, possibilitando o comparativo com a versão anterior da máquina que empregou ímãs de seção quadrada. Mudanças físicas e no sistema de acionamento da máquina, e ensaios de frenagem dinâmica foram realizados. Modelagem analítica para indução magnética foi desenvolvida utilizando-se da técnica de Transformação Conforme. O trabalho busca apresentar as características da máquina e justificativas que demonstram o seu potencial de aplicabilidade em um subsistema veicular sob frenagem regenerativa e a capacidade de fornecimento de energia a um sistema de armazenamento com uma parte de energia cinética, ou seja, baterias e supercapacitores.
This work is carried out with the aim to study the application, by a vehicular braking system, of a brushless electrical machine with a toroidal armature core, and axial magnetic flux delivered by rare earth permanent magnets, the so-called Torus machine. The machine was built in the LMEAE, and previously studied as a motor by other work. However, in order to assess its performance in a braking system, the focus is the point of view of the machine as a generator. Static and dynamic tests are implemented as well as a numerical model by means of the finite element method, in order to compare the machine with sector poles permanent magnets and with square magnet poles. Physical changes and on the driving system of the machine, and dynamic braking tests are performed. The analytical modelling for the magnetic induction was developed using the technique of conformal transformation. The study aims to present the features of the machine and demonstrates its potential applicability to a vehicular subsystem under regenerative braking and the ability to supply an energy storage system with part of the kinetic energy, i.e. batteries and super capacitors.

Je jasné, že nejúspěšnější konstrukce zahrnuje postup vícefázového řízení, ve kterém každá fáze může být považována za samostatný modul. Provoz kterékoliv z jednotek musí mít minimální vliv na ostatní, a to tak, že v případě selhání jedné jednotky ostatní mohou být v provozu neovlivněny. Modulární řešení vyžaduje minimální elektrické, magnetické a tepelné ovlivnění mezi fázemi řízení (měniče). Synchronní stroje s pulzním tokem a permanentními magnety se jeví jako atraktivní typ stroje, jejíž přednostmi jsou vysoký kroutící moment, jednoduchá a robustní konstrukce rotoru a skutečnost, že permanentní magnety i cívky jsou umístěny společně na statoru. FS-PMSM jsou poměrně nové typy střídavého stroje stator-permanentní magnet, které představují významné přednosti na rozdíl od konvenčních rotorů - velký kroutící moment, vysoký točivý moment, v podstatě sinusové zpětné EMF křivky, zároveň kompaktní a robustní konstrukce díky umístění magnetů a vinutí kotvy na statoru. Srovnání výsledků mezi FS-PMSM a klasickými motory na povrchu upevněnými PM (SPM) se stejnými parametry ukazuje, že FS-PMSM vykazuje větší vzduchové mezery hustoty toku, vyšší točivý moment na ztráty v mědi, ale také vyšší pulzaci díky reluktančnímu momentu. Pro stroje buzené permanentními magnety se jedná o tradiční rozpor mezi požadavkem na vysoký kroutící moment pod základní rychlostí (oblast konstantního momentu) a provozem nad základní rychlostí (oblast konstantního výkonu), zejména pro aplikace v hybridních vozidlech. Je předložena nová topologie synchronního stroje s permanentními magnety a spínaným tokem odolného proti poruchám, která je schopná provozu během vinutí naprázdno a zkratovaného vinutí i poruchách měniče. Schéma je založeno na dvojitě vinutém motoru napájeném ze dvou oddělených vektorově řízených napěťových zdrojů. Vinutí jsou uspořádána takovým způsobem, aby tvořila dvě nezávislé a oddělené sady. Simulace a experimentální výzkum zpřesní výkon během obou scénářů jak za normálního provozu, tak za poruch včetně zkratových závad a ukáží robustnost pohonu za těchto podmínek. Tato práce byla publikována v deseti konferenčních příspěvcích, dvou časopisech a knižní kapitole, kde byly představeny jak topologie pohonu a aplikovaná řídící schémata, tak analýzy jeho schopnosti odolávat poruchám.

碩士
國立臺灣大學
機械工程學研究所
99
The purpose of this paper is to establish and to investigate a Vehicle Dynamic Control Strategy for an independent four-wheel driven electric vehicle. This strategy achieved those functions of Traction Control System (TCS), Anti-Slip Braking Control (ASBC), Active Yaw Control (AYC), and regenerative brake by integrating traction torque control, braking force control, and four-wheel torque distribution. In recent years, many research organizations and car manufacturer started electric vehicle (EV) development due to oil crisis and global warming problems. Compared to Internal Combustion Engine Vehicles (ICEV), EVs can not only reduce petroleum usage and greenhouse gas emission, but also have great potential in two aspects. First, electric power systems can recover vehicle kinetic energy during braking, which is beneficial to extend range and reduce wear of mechanical brake unit. Second, electric power systems have faster and more precise response than gasoline engine systems. Electric power systems are also capable to be arranged as independent four-wheel drive, which has high degrees of freedom for vehicle dynamic control. In this study we make use of those advantages mentioned above, and integrated TCS, ASBC, AYC, regenerative brake controller in Vehicle Control Unit (VCU) software, which formed a complete vehicle dynamic control system. Then, an independent four-wheel driven EV dynamic model is built up using MATLAB/Simulink and CarSim. This model is use to test and verify controller performance in simulation.

In this study, various stability control systems are developed to remove the lateral instability of a conventional articulated steer vehicle (ASV) during the oscillatory yaw motion or “snaking mode”. First, to identify the nature of the instability, some analyses are performed using several simplified models. These investigations are mainly focused on analyzing the effects of forward speed and of two main subsystems of the vehicle, the steering system and tires, on the stability. The basic insights into the stability behavior of the vehicle obtained from the stability analyses of the simplified models are verified by conducting some simulations with a virtual prototype of the vehicle in ADAMS. To determine the most critical operating condition with regard to the lateral stability and to identify the effects of vehicle parameters on the stability, various studies are performed by introducing some modifications to the simplified models. Based on these studies, the disturbed straight-line on-highway motion with constant forward speed is recognized as the most critical driving condition. Also, the examinations show that when the vehicle is traveling with differentials locked, the vehicle is less prone to the instability. The examinations show that when the vehicle is carrying a rear-mounted load having interaction with ground, the instability may happen if the vehicle moves on a relatively good off-road surface. Again, the results gained from the analyses related to the effects of the vehicle parameters and operating conditions on the stability are verified using simulations in ADAMS by making some changes in the virtual prototype for any case. To stabilize the vehicle during its most critical driving condition, some studies are directed to indicate the shortcomings of passive methods. Alternative solutions, including design of different types of stability control systems, are proposed to generate a stabilizing yaw moment. The proposed solutions include an active steering system with a classical controller, an active torque vectoring device with a robust full state feedback controller, and a differential braking system with a robust variable structure controller. The robust controllers are designed by using simplified models, which are also used to evaluate the ability to deal with the uncertainties of the vehicle parameters and its variable operating conditions. These controllers are also incorporated into the virtual prototype, and their capabilities to stabilize the vehicle in different operating conditions and while traveling on different surfaces during the snaking mode are shown.