Hybrid Feedback Linearization Slip Control for Anti-lock Braking System

Abstract

The Anti-lock braking system (ABS) is an active safety device in road vehicles, which during hard braking maximizes the braking force between the tyre and the road irrespective of the road conditions. This is accomplished by regulating the wheel slip around its optimum value. Due to the high non-linearity of the tyre and road interaction, and uncertainties from vehicle dynamics, a standard PID controller will not suffice. This paper therefore proposes a non-linear control design using input-output feedback linearization approach. To enhance the robustness of the non-linear controller, an integral feedback method was employed. The stability of the controller is analysed in the Lyapunov sense. To demonstrate the robustness of the proposed controller, simulations were conducted on two different road conditions. The results from the proposed method exhibited a more superior performance and reduced the chattering effect on the braking torque compared to the performance of the standard feedback linearization method.

Antilock Braking System Using Dynamic Speed Estimation

“…By using this assumption, it is possible to estimate the force vector and use it to design a suitable controller that limits the forces that cause slip. A suitable controller can be a sliding mode controller as designed by Kacroo and Tomizuka [3] or by employing feedback linearization [4] with linear PID controller without considering the actual deceleration of velocity of the vehicle.…”

“…It is important to select a true value of slip because it will help in selecting the right coefficient of friction, which is dependent upon the precise estimation of the velocity [1,2]. Figure 3 shows that at a slip S=0.19, maximum friction is achieved [2,3] and when the slip becomes more than 0.19, the adhesion coefficient degrades resulting in the loss of steering ability and longer braking distance. The figure also illustrates the reason of marked ABS failure on icy and degraded performance on wet roads.…”