Dzmitry Savitski

A Survey of Traction Control and Antilock Braking Systems of Full Electric Vehicles With Individually Controlled Electric Motors

Wheel slip control for ground vehicles with individually controlled electric motors can be realized with strategies that can significantly differ from the conventional antilock braking system (ABS) and traction control (TC) system. This paper provides a review of state-of-the-art technology and recent developments in TC and ABSs using the actuation of electric motors. Particular attention is paid to the realization of slip estimators, the formalization of torque demand, and the control methods applied for the implementation of TC and ABSs. The performed analysis allowed for the differentiation of several most elaborated methods for slip and torque control and defining still imperfectly investigated problems to be covered by the further development of TC and ABSs for full electric vehicles.

Hardware-in-the-loop test rig for integrated vehicle control systems

Abstract The paper introduces the architecture and technical realization of the hardware-in-the-loop (HIL) platform designed specifically for development and testing of integrated vehicle control systems. Starting with the formulation of functional and configuration requirements, the work explains a concept of new HIL test rig and describes its main components. The proposed HIL platform allows integrated testing of different configurations of brake systems, steering, and dynamic tyre pressure control. The case study illustrates operation of the test rig.

Vehicle dynamics control with energy recuperation based on control allocation for independent wheel motors and brake system

This work proposes an optimal control allocation method for the brake system and the wheel motors of an electric vehicle. The realisation of the method is proposed for vehicle dynamics control and energy recuperation. The control allocation takes into account temperature of electric motors, SOC and voltage of battery, vehicle velocity, fault situations, wheel slip, and vehicle subsystem prioritisation depending on parameters of vehicle dynamics. To illustrate the functional properties of the control allocation method, the corresponding simulation study is performed for the straight-line braking and ‘sine with dwell’ cornering. The simulations use a number of mathematical models including the 14 DoF model of vehicle motion and the models of electric vehicle systems. The simulation results confirmed effectiveness of the proposed approach both for regenerative braking and vehicle stability.

Electric vehicles with individually controlled on-board motors: Revisiting the ABS design

The paper introduces the anti-lock braking system (ABS) designed for the all-wheel drive full electric vehicle equipped with four on-board motors. The main features of the ABS under consideration are (i) continuous wheel slip control with feedforward and feedback controller parts, and (ii) versatile actuation architecture realizing pure electric braking, braking with electro-hydraulic decoupled brake systems, and blended braking with operation both of friction brakes and electric motors in regenerative mode. Results of ABS validation demonstrate essential benefits of the developed control strategy for brake performance, precise wheel slip tracking, and drive comfort at braking. Adaptive properties of the proposed ABS are discussed for test cases including the transient road friction.

Systematization of Integrated Motion Control of Ground Vehicles

This paper gives an extended analysis of automotive control systems as components of the integrated motion control (IMC). The cooperation of various chassis and powertrain systems is discussed from a viewpoint of improvement of vehicle performance in relation to longitudinal, lateral, and vertical motion dynamics. The classification of IMC systems is proposed. Particular attention is placed on the architecture and methods of subsystems integration.

All-wheel-drive electric vehicle with on-board motors: Experimental validation of the motion control systems

This paper discusses the vehicle dynamics control system of an all-wheel-drive electric vehicle with four on-board motors. Each driveline is characterized by complex torsional dynamics caused by the gearbox and the half-shaft located between the electric motor and the wheel. Such a drivetrain configuration can benefit from a specific controller, i.e., the active vibration controller (AVC), which increases the damping ratio of the actuation system. The AVC enhances the effectiveness of the other vehicle dynamics controllers such as the direct yaw moment controller (DYC) and the wheel slip controllers (WSCs). This study introduces examples of AVC, DYC and WSC implementations, and their experimental validation on the electric vehicle demonstrator of the European Union FP7 E-VECTOORC project. The experimental results confirm that the powertrain architecture with individually controlled on-board motors significantly improves the traction, braking and cornering capabilities of the electric vehicle, while increasing comfort and active safety.

Automotive magnetorheological dampers: modelling and parameter identification using contrast-based fruit fly optimisation

The present study discusses the mechanical behaviour and modelling of a prototype automotive magnetorheological (MR) damper, which presents different viscous damping coefficients in jounce and rebound. The force generated by the MR damper is measured at different velocities and electrical currents, and a modified damper model is proposed to improve fitting of the experimental data. The model is calibrated by means of parameter identification, and for this purpose a new swarm intelligence algorithm is proposed, that we call the contrast-based Fruit Fly Optimisation Algorithm (c-FOA). The performance of c-FOA is compared with that of Genetic Algorithms, Particle Swarm Optimisation, Differential Evolution and Artificial Bee Colony. The comparison is made on the basis of no a-priori knowledge of the damper model parameters range. The results confirm the good performance of c-FOA under parametric range uncertainty. A sensitivity analysis discusses c-FOA’s performance with respect to its tuning parameters. Finally, a ride comfort simulation study quantifies the discrepancies in the results, for different identified damper model sets. The discrepancies underline the importance of accurately describing MR damper nonlinear behaviour, considering that virtual sign-off processes are increasingly gaining momentum in the automotive industry.

Active Brake Judder Compensation Using an Electro-Hydraulic Brake System

Geometric imperfections on brake rotor surface are well-known for causing periodic variations in brake torque during braking. This leads to brake judder, where vibrations are felt in the brake peda ...

Hierarchical control of overactuated vehicles via sliding mode techniques

Overactuated vehicle platforms with in-wheel motors make it possible to realize vehicle control systems that can yield the desired dynamic response while simultaneously optimizing various performance criteria. In this context, this paper analyzes how sliding mode techniques can be profitably applied to the yaw-rate tracking problem that governs the high-level vehicle control layer. Specifically, three different algorithms are compared: the standard, the switched and the adaptive formulations of the second-order sliding mode controller. Extensive simulation and hardware-in-the-loop (HIL) testing show that adaptation features allow more flexibility and a better closed-loop behaviour in the face of the uncertainties affecting the overall system.

ADVANCED COST FUNCTIONS FOR EVALUATION OF LATERAL VEHICLE DYNAMICS

The paper introduces the method of assessment of vehicle manoeuvres through a set of global cost functions. The corresponding cost functions can be derived for different domains like longitudinal and lateral dynamics, driving comfort and other. The procedures of the computation of the cost functions include in general: (1) Selection of vehicle dynamics parameters relevant to the domain; (2) Transformation the appointed parameter to the dimensionless form; (3) Definition of weighting factors for each of the appointed parameters with taking into account that the weighting factors can be variable depending on the type of the vehicle manoeuvre as well as on the driving conditions; (4) Calculation of the cost function for the selected domain; (5) Calculation of a global cost function in the case of the integrated assessment of the manoeuvre through several domains of the vehicle dynamics. The described procedures are discussed in the paper as applied to the domain of lateral vehicle dynamics. The parameters chosen for the calculation of the corresponding cost function are the lateral acceleration a y , the yaw rate dψ/dt, and the sideslip angle β. To transform these parameters to a dimensionless form, the procedure is proposed that uses the function of root mean square of deviations between reference and actual values for each variable. This procedure implements also an original method of definition of reference values for lateral acceleration a y and yaw rate dψ/dt. The method is based on the variation of understeer characteristic of the baseline vehicle with the aim to extend the linear region and to reduce the understeer gradient as well as to increase the maximum level of lateral acceleration. The validation of the developed methods and procedures is illustrated by way of model-in-the-loop simulation. The test programme covers several standard manoeuvres—steady-state circle, slalom and avoidance manoeuvre—performed for a simulator, medium-sized passenger car. The numerical values of the cost functions for each manoeuvre are introduced and analyzed. The further applications of the developed technique can be: (1) Assessment of vehicle dynamics based on criterions of performance and stability; (2) Optimization of vehicle dynamics control systems; (3) Choice of proper control strategies/tuning of control gains and resolution of critical control situations by simultaneous operation of several systems like ABS, TCS, TV/vehicle dynamics control.