Development of an Anti-Lock Brake System for Motorcycle

An Anti-Lock Brake System (ABS) system is developed for motorcycles using different control laws to improve the safety during emergent braking conditions. The mechanical design problem is first investigated so as to modify a scooter to be equipped with the proposed ABS brake system and to set up experimental test stand. For ABS control, the slip control, P1R3, and P2R4 methods are used to implement the controller using an Intel 80196KC single chip microcomputer. The hard-ware-in-the-loop (HITL) simulation is also performed in PC to check the performance in various road conditions including dry and wet roads. It is found experimentally that both P1R3 and P2R4 can both achieve ABS function, but P2R4 performs more desirably than P1R3 method.     

Literature review and fundamental approaches for vehicle and tire state estimation*

ABSTRACT

Most modern day automotive chassis control systems employ a feedback control structure. Therefore, real-time estimates of the vehicle dynamic states and tire-road contact parameters are invaluable for enhancing the performance of vehicle control systems, such as anti-lock brake system (ABS) and electronic stability program (ESP). Today's production vehicles are equipped with onboard sensors (e.g. a 3-axis accelerometer, 3-axis gyroscope, steering wheel angle sensor, and wheel speed sensors), which when used in conjunction with certain model-based or kinematics-based observers can be used to identify relevant tire and vehicle states for optimal control of comfort, stability and handling. Vehicle state estimation is becoming ever more relevant with the increased sophistication of chassis control systems. This paper presents a comprehensive overview of the state-of-the-art in the field of vehicle and tire state estimation. It is expected to serve as a resource for researchers interested in developing vehicle state estimation algorithms for usage in advanced vehicle control and safety systems.     

Integrated Control of Active Rear Wheel Steering and Direct Yaw Moment Control

SUMMARY

An integrated control system of active rear wheel steering (4WS) and direct yaw moment control (DYC) is presented in this paper. Because of the tire nonlinearity that is mainly due to the saturation of cornering forces, vehicle handling performance is improved but limited to a certain extent only by steering control. Direct yaw moment control using braking and/or driving forces is effective not only in linear but also nonlinear ranges of tire friction circle. The proposed control system is a model matching controller which makes the vehicle follow the desired dynamic model by the state feedback of both yaw rate and side slip angle. Various computer simulations are carried out and show that vehicle handling performance is much improved by the integrated control system.     

气压ABS系统流量特性的实验研究

开发了气压ABS电磁阀测试系统，建立了气室充、放气过程压力变化的微分方程，结合两者研究了气压ABS系统的流量特性，获得了某中型客车ABS系统在不同情况下的流量系数。讨论了ABS电磁阀的结构参数和动作频率对整个系统流量特性的影响，并得到了几种典型动作频率下的流量系数。建立的气室压力模型和所求得的流量系数为气压ABS控制逻辑的设计提供了依据。     

Semi-Active Attitude and Vibration Control

SUMMARY

The paper discusses the attitude and vibration control of a passenger car on the basis of a full vehicle model. The analysis presented consists of two parts: (I) The introduction of a newly developed semi-active anti-roll/pitch system, (ii) An example of an actively suspended full vehicle model using a simple control strategy to improve ride comfort. The attitude control using semi-actively generated compensation forces prevents the car from rolling in curves and pitching during braking or accelerating. The strength of the system is the small energy consumption. The performance of the combination of both attitude and vibration control can compete with a fully active suspension system.     

Adaptive Control of 4WS System by Using Neural Network

SUMMARY

An adaptive control system of the model following type is proposed for drive motion control of a four wheel steering (4WS) car with using neural network (NN) which has mastered nonlinear friction force between tire and road surface. A model of one rigid body is adopted which represents appropriately two kinds of car motion caused by steering action, namely the lateral displacement and the yawing rotation, and an equation of motion is described in a simplified form to make a system equation for motion control possible. Nonlinear relation between the cornering force of tire and the slip angle is obtained by numerical analysis with the tire model proposed by E. Fiala, taking friction coefficient and car speed as the parameters. The result is used as the teaching signal for NN. Three NN are used in the control system composed of both the feed-forward and the feedback circuits in order to realize adaptive control. Validity and usefulness of the proposed adaptive control system with NN are verified by three kinds of computer simulation.     

Additional 4WS and Driver Interaction

SUMMARY

This investigation is based on a complex 4-wheel vehicle model of a passenger car that includes steering system and drive train. The tyre properties are described for all possible combined longitudinal and lateral slip values and for arbitrary friction conditions. The active part is an additional steering system of all 4 wheels, additionally to the driver's steering wheel angle input. Three control levels are used for the driver model that thereby can follow a given trajectory or avoid an obstacle.

The feedback control of the additional 4 wheel steering is based on an observer which can also have adaptive characteristics. Moreover a virtual vehicle model in a feedforward scheme can provide desired steering characteristics.

To get information for critical situations a cornering manoeuvre with sudden u-split conditions is simulated. Further a similar manoeuvre is used to evaluate the reentry in a high friction area from low friction conditions. And finally the performance of the controller is shown in a severe lane change manoeuvre.     

Experimental investigations on continuous regenerative anti-lock braking system of full electric vehicle

Functions of anti-lock braking for full electric vehicles (EV) with individually controlled wheel drive can be realized through conventional brake system actuating friction brakes and regenerative brake system actuating electric motors. To analyze advantages and limitations of both variants of anti-lock braking systems (ABS), the presented study introduces results of experimental investigations obtained from proving ground tests of all-wheel drive EV. The brake performance is assessed for three different configurations: hydraulic ABS; regenerative ABS only on the front axle; blended hydraulic and regenerative ABS on the front axle and hydraulic ABS on the rear axle. The hydraulic ABS is based on a rule-based controller, and the continuous regenerative ABS uses the gain-scheduled proportional-integral direct slip control with feedforward and feedback control parts. The results of tests on low-friction road surface demonstrated that all the ABS configurations guarantee considerable reduction of the brake distance compared to the vehicle without ABS. In addition, braking manoeuvres with the regenerative ABS are characterized by accurate tracking of the reference wheel slip that results in less oscillatory time profile of the vehicle deceleration and, as consequence, in better driving comfort. The results of the presented experimental investigations can be used in the process of selection of ABS architecture for upcoming generations of full electric vehicles with individual wheel drive.     

Prediction of antilock braking system condition with the vehicle stationary using a model-based approach

An Antilock Braking System (ABS) is one of the most important safety facilities equipped in modern vehicles. A self-test is therefore embedded into its ECU to identify any electronic malfunction. However there is no effective method to predict or check its mechanical conditions routinely to ensure its functionality. Because the ABS system is merely actuated above a particular speed in emergency stops, the current brake test facilities are not adequate for ABS test. Because of the dangers involved it would not be acceptable to use a public road to implement such a practice for fault detection so an alternative means must be sought. To provide a safe and convenient solution this paper proposes a novel method to predict ABS faults whilst the vehicle is stationary. In this situation a model-based approach is applied to predict various faults from the ABS, especially from its hydraulic subsystem. As such, a mathematic model is developed to describe the operating processes of ABS including possible faulty conditions. An autonomous control strategy is also designed to actuate the control module independently without the knowledge of the control algorithms embedded in an ABS control module. This approach is evaluated through a Simulink simulation.     

A vehicle ABS adaptive sliding-mode control algorithm based on the vehicle velocity estimation and tyre/road friction coefficient estimations

A sliding-mode observer is designed to estimate the vehicle velocity with the measured vehicle acceleration, the wheel speeds and the braking torques. Based on the Burckhardt tyre model, the extended Kalman filter is designed to estimate the parameters of the Burckhardt model with the estimated vehicle velocity, the measured wheel speeds and the vehicle acceleration. According to the estimated parameters of the Burckhardt tyre model, the tyre/road friction coefficients and the optimal slip ratios are calculated. A vehicle adaptive sliding-mode control (SMC) algorithm is presented with the estimated vehicle velocity, the tyre/road friction coefficients and the optimal slip ratios. And the adjustment method of the sliding-mode gain factors is discussed. Based on the adaptive SMC algorithm, a vehicle's antilock braking system (ABS) control system model is built with the Simulink Toolbox. Under the single-road condition as well as the different road conditions, the performance of the vehicle ABS system is simulated with the vehicle velocity observer, the tyre/road friction coefficient estimator and the adaptive SMC algorithm. The results indicate that the estimated errors of the vehicle velocity and the tyre/road friction coefficients are acceptable and the vehicle ABS adaptive SMC algorithm is effective. So the proposed adaptive SMC algorithm can be used to control the vehicle ABS without the information of the vehicle velocity and the road conditions.     

Feedforward and Crone Feedback Control Strategies for Automobile ABS

Summary As mechatronic subsystems and especially new emerging technologies for brake systems are more and more developed, a new control architecture for ABS is proposed. The control architecture is designed using both feedback and feedforward controls that command pressure-controlled proportional servo-valves. The methods are developed to compensate for the uncertainty associated with the state of the road surface. The advantages of this strategy compared to the existing ABS strategy are discussed including simulations results using a complete vehicle and brake system model.     

Design of an Active Unilateral Brake Control System for Five-Axle Tractor-Semitrailer Based on Sensitivity Analysis

SUMMARY

This paper presents the results of a parametric sensitivity analysis of a five-axle tractor-semitrailer vehicle combination using 3-DOF linear yaw/plane model. The first order logarithmic sensitivity functions are derived with respect to several vehicle design parameters. For stabilization of the vehicle's directional behaviour a fairly new control concept called “Active Unilateral Braking Control (AUBC)” acting on the tractor rear wheel's in order to produce a stabilizing yaw torque is investigated. The AUBC system improves not only the directional stability, but also affects the roll dynamics of the vehicle. The sensitivity of the controlled vehicle system with linear quadratic controller (LQR) is also examined, a robust controller design procedure is proposed as a result of the sensitivity analysis. The robustness of this controller in the presence of both internal (including parametric uncertainties, non-linear dynamics) and external disturbances (such as road irregularities and side wind) allows its implementation with confidence with a non-linear vehicle model. The applicability of this control system to a non-linear vehicle model is tested using a 34 DOF, non-linear vehicle model of the tractor-semitrailer combination.     

Feedforward and Crone Feedback Control Strategies for Automobile ABS

Summary As mechatronic subsystems and especially new emerging technologies for brake systems are more and more developed, a new control architecture for ABS is proposed. The control architecture is designed using both feedback and feedforward controls that command pressure-controlled proportional servo-valves. The methods are developed to compensate for the uncertainty associated with the state of the road surface. The advantages of this strategy compared to the existing ABS strategy are discussed including simulations results using a complete vehicle and brake system model.     

Fuzzy Control of Clutch Engagement for Automated Manual Transmission

SUMMARY

This paper presents a fuzzy control system for the clutch engagement of an automated manual transmission. The servomechanism is assembled with a three-port pneumatic pressure-proportional valve and a position-sensing cylinder which control the release-lever displacement of 25 mm within the position preciseness of 0.1 mm against maximum spring load of 2kN. The fuzzy system is skillful to estimate the driver's will from the accelerator pedal operation. The servomechanism is mounted on a commercial vehicle with 4-ton pay-load. The system parameters are set up by bond graphs simulation and empirical performance tests are carried by using an oil-hydraulically operated engine-vehicle testing rig with a maximum torque capacity of 400 Nm.     

防抱死制动系统模糊自学习控制研究

由于车辆参数和运行工况的复杂多变，针对特定参数和路面条件所设计的防抱死制动系统往往难以适应。为解决这一问题，文中首先建立了带有盘式制动器的双轮车辆直线制动系统的数学模型；而后提出了模糊自学习控制策略，该方案通过引入模糊学习机制以调整模糊控制器的规则集，可使车辆对象输出跟踪理想参考模型的输出；接着对所设计控制算法在不同路面条件下进行了性能模拟；最后开发了模糊自学习微控制器，基于硬件在环仿真技术，对设计控制器的性能进行了实验验证。     

Improvement of drivability and fuel economy with a hybrid antiskid braking system in hybrid electric vehicles

When braking on wet roads, Antilock Braking System (ABS) control can be triggered because the available brake torque is not sufficient. When the ABS system is active, for a hybrid electric vehicle, the regenerative brake is switched off to safeguard the normal ABS function. When the ABS control is terminated, it would be favorable to reactivate the regenerative brake. However, recurring cycles from ABS to motor regenerative braking could occur. This condition is felt to be unpleasant by the driver and has adverse effects on driving stability. In this paper, a novel hybrid antiskid braking system using fuzzy logic is proposed for a hybrid electric vehicle that has a regenerative braking system operatively connected to an electric traction motor and a separate hydraulic braking system. This control strategy and the method for coordination between regenerative and hydraulic braking are developed. The motor regenerative braking controller is designed. Control of regenerative and hydraulic braking force distribution is investigated. The simulation and experimental results show that vehicle braking performance and fuel economy can be improved and the proposed control strategy and method are effective and robust.     

A Versatile Flat Track Tire Testing Machine

Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: – a hydraulically operated tire support and loading system with wide operating ranges; – a computer controlled brake system to simulate braking maneuvers with ABS systems; – a complete sensorial system; – a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools.     

A Versatile Flat Track Tire Testing Machine

Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: - a hydraulically operated tire support and loading system with wide operating ranges; - a computer controlled brake system to simulate braking maneuvers with ABS systems; - a complete sensorial system; - a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools.     

Design of Optimal Four-Wheel Steering System

SUMMARY

Optimal design of the four wheel steering (4WS) system of the ground vehicle is studied. 4WS vehicles with the optimal control scheme are considered first. General formulation of the optimal control law is developed based on the linear quadratic regulator theory. The vehicle speed function (VSF) based 4WS vehicle with a simple feedback controller is considered as a special case of the optimal system. Two new designs of the VSF 4WS system are proposed and their performances are compared with the optimal 4WS systems and the existing VSF 4WS system. The first system is designed for the maximum stability while the second system is designed to emulate the response of the optimal 4WS vehicle. Advantages of the new VSF designs are discussed.