Nested adaptive super-twisting sliding mode control design for a vehicle steer-by-wire system

The driving motor of the electric vehicle (EV) can recover the kinetic energy during normal braking maneuvers by a regenerative function At the same time, its dynamic torque response proves to be accurate and fast for an emergency braking, namely an anti-lock braking, with the coordinated control of the frictional braking system However, vehicle transmission properties will deteriorate the control performance of the motor, especially in the anti-lock braking process A novel permanent magnet synchronous motor (PMSM) control method is proposed considering the transmission influence on this high-dynamic braking process of the pure EV First, the EV's dynamic model, which includes the PMSM field-oriented control model, the transmission dynamic model, and the hydraulic braking system, is built, and the influences of transmission elasticity and backlash non-linearity on the motor-braking torque are analyzed Then, based on the wheel slip ratio target of the anti-lock braking, the novel mode-switching method for the motor-torque control between the backlash sliding-mode compensation and the elasticity double-closed-loop PID compensation is put forward Two state-of-the-art anti-lock braking algorithms, which simplify the transmission properties, the slip ratio phase-plane theory, and the sliding-mode control, are compared with the proposed method Simulation and test-bench experiment results show that, on different test-road surfaces, the mode-switching PMSM control can effectively compensate for transmission effects and significantly improve the EV's anti-lock braking comfort, stability, and maneuverability with fast and accurate motor-torque regulating

Novel PMSM Control for Anti-Lock Braking Considering Transmission Properties of the Electric Vehicle

This paper focuses on the controller design using fuzzy sliding mode control (FSMC) with application to electro-mechanical brake (EMB) systems using BLDC Motor. The EMB controller transmits the control signal to the motor driver to rotate the motor. The torque distribution of motors is studied in this paper actually. Firstly, the model of the EMB system is established. Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force. Due to the fact that the EMB system is nonlinear and uncertain, a FSMC strategy based on wheel slip ratio is proposed, where both the normal and emergency braking conditions are taken into account. The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process, while the switching control law is adjusted by the fuzzy corrector. The simulation results illustrate that the FSMC strategy has the superior performance, better adaptability to various types of roads, and shorter braking distance, as compared to PID control and traditional sliding mode control technologies. Finally, the hardware-in-loop (NIL) experimental results have exemplified the validation of the developed methodology.

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Fuzzy sliding mode control based on longitudinal force estimation for electro-mechanical braking systems using BLDC motor

This paper reviews and summarizes the development, key technologies, and application of brake-by-wire (BBW) actuators. BBW is the technology orientation of future vehicle brake system. The main feature of BBW is to replace some of the mechanical and hydraulic components of traditional brake system with electronic control components, and use cables and wires to transmit energy and signals. BBW actuators have outstanding advantages, such as fast response, accurate control, and compact structure. They are easy to integrate with active safety functions and they are easily matched with the regenerative braking systems of electric vehicle. First, this paper summarizes the classification, characteristics, performance, and architecture of BBW actuators. Subsequently, the braking process regulation of vehicle is considered to be the main target, which is summarized from two aspects of actuator regulation and braking force distribution. The state estimation algorithm and control algorithm applied to these actuators are summarized and analyzed, and the development trend, challenges, and schemes of the braking force distribution are proposed. The development and research trend of braking force match strategies between the regenerative brake system and BBW system are also analyzed and summarized. The further electrification and intelligence of vehicle demand BBW’s braking force control method and distribution method must have higher control accuracy, stronger robustness, and wider adaptability, and the effects on braking comfort and handling stability must be further discussed.

https://www.mdpi.com/2076-0825/9/1/15/pdf

Review on the Development, Control Method and Application Prospect of Brake-by-Wire Actuator

This paper presents a predictive braking control algorithm for electric vehicles with redundant braking actuators, composed of friction brake actuator(s) and electric motor(s). The proposed algorithm is based on a model predictive control framework and is able to optimally tackle several control goals, such as maximization of energy recuperation and wheel slip regulation, while taking into account actuation dynamics and constraints. The braking control algorithm was simulated and experimentally validated on the ROMO research vehicle. The obtained results demonstrate that in comparison with state-of-the-art control techniques, the proposed model predictive control approach is able to reduce the torque tracking error up to 60%, and improve the deceleration during emergency braking up to 10%.

Predictive Brake Control for Electric Vehicles

A novel method of all-wheel braking force allocation during a braking-in-turn maneuver is proposed for vehicles with the brake-by-wire (BBW) system. The concept of stability priority is applied in distributing the braking force to each wheel, which means that the stability performance has priority over the braking demand during a braking-in-turn maneuver. Based on this principle, I-curves for braking-in-turn maneuvers with respect to three parameters are developed using the graphics of a single-track vehicle model, defining the force allocation between the front and rear axles. Then, the distributed braking force of the front and rear axles is allocated between the inner and outer wheels based on the load transfer. The simulation and hardware-in-the-loop (HIL) experimental results show that the proposed allocation strategy makes good use of adhesion and ensures vehicle stability during a braking-in-turn maneuver. The proposed method provides theoretical guidelines on independent braking force control in the BBW system, which enhances vehicle stability and braking performance.

All-Wheel Braking Force Allocation During a Braking-in-Turn Maneuver for Vehicles With the Brake-by-Wire System Considering Braking Efficiency and Stability

Regenerative braking significantly improves the energy efficiency in electric vehicles. Cooperative control between regenerative braking and friction braking during anti-lock braking control is a critical issue in brake system coupling. For safety concerns, regenerative braking is often terminated at the beginning of anti-lock braking control. Oscillations between activation of an anti-lock braking system and exit from anti-lock braking system control may occur under poorly matched control parameters. To solve these problems, we propose an index that indicates the possibility of activation of an anti-lock braking system. It is derived by a fuzzy logic algorithm which is based on the estimated regenerative braking torque, the estimated friction braking torque and other vehicle state variables. Regenerative braking can be adjusted on the basis of the index to ensure that such braking is of a low level when an anti-lock braking system is activated. Simulations and experiments are carried out to evaluate the ...

Cooperative control of regenerative braking and friction braking in the transient process of anti-lock braking activation in electric vehicles:

Frequent acceleration and deceleration of vehicle especially in urban traffic arouse relative frequent pitch motion accordingly. As the orientation of vehicle acceleration alters, the inertia of human body and the pitch motion transferred by the suspension cause passengers’ body to swing back and forth, thus leading to ride discomfort, even motion sickness. In particular, such ride discomfort is noticeable in the post-braking phase, resulting from the subsequent rebound of the vehicle body after complete stop, according to the subjective experiment in this paper. The suspension characteristics are dominant in the pitch motion of post-braking phase. This paper applies an active suspension based on LQR controller to attenuate the negative rebound effect. Considering the trade-off between rebound time and rebound impact, a LQR optimal controller is proposed to control the active suspension, minimizing the negative pitch motion and improving the braking ride comfort. The simulation result indicates that the vehicle rebound in the post-braking phase is conspicuous around the resonant frequency of the vehicle body. Furthermore, the magnitude of frequency response at this critical area has been decreased and the ride comfort in post-braking phase has been improved with the proposed LQR controller.Copyright © 2015 by ASME

Ride Comfort Improvement in Post-Braking Phase Using Active Suspension

ISO 26262 Concept Phase Analysis on Distributed Electro-Hydraulic Braking System: The Influence of System Architecture on ASIL Decomposition

An adaptive searching algorithm for the optimal slip during ABS wheel slip control is proposed. By taking advantage of the fluctuation of wheel slip control, the direction towards the optimal slip can be found, and the target slip calculated by the algorithm asymptotically converged to the optimal slip, which is proved using the Lyapunov theory. A gain-scheduling wheel slip controller is developed to control the wheel slip to the target slip. Simulations on the uniform road and on the road with changed friction are carried out to verify the effectiveness of the proposed algorithm. Simulation results show that the ABS algorithm using the proposed searching algorithm can make full use of the road friction and adapts to road friction changes. Comparing with the conventional rule-based ABS, the pressure modulation amplitude and wheel speed fluctuation is significantly reduced, improving control performance of ABS.Copyright © 2015 by ASME

Lei Zhang

Papers

All-Wheel Braking Force Allocation During a Braking-in-Turn Maneuver for Vehicles With the Brake-by-Wire System Considering Braking Efficiency and Stability

Cooperative control of regenerative braking and friction braking in the transient process of anti-lock braking activation in electric vehicles:

Ride Comfort Improvement in Post-Braking Phase Using Active Suspension

ISO 26262 Concept Phase Analysis on Distributed Electro-Hydraulic Braking System: The Influence of System Architecture on ASIL Decomposition

Anti-Lock Wheel Slip Control With an Adaptive Searching Algorithm for the Optimal Slip