The main motivation for using reset control is the overcoming of fundamental limitations or trade-offs of conventional controllers: with the conventional controllers if we want a fast braking response, the system is fragile and sensitive to uncertainties; and if we want a robust system, this requires slower braking actions.
Reset control is a novel technique that achieves more robust and fester braking responses in a way that no other conventional controller is able to produce.
Description of the technology
To maximize the benefits of the implementation of new technologies in brake systems such as electromechanical brake actuators and a brake-by-wire system, it is necessary to count with slip controllers, since they will act as independent brake forces in each of the wheels. A research group from the University of Vigo has developed a novel Wheel slip reset controller for brake systems that will lead to an improvement of the robustness and performance of the system. This improvement implies the reduction of the braking distance and a better tire and road friction estimation. The proposed wheel slip reset controller is a versatile controller with a simple model-based design, that improves performance and robustness simultaneously.
The limitations of conventional slip controllers arise from the linear nature of standard control actions (proportional, integral, derivative). Technically speaking, linear systems are constrained by fundamental limitations (i.e. not all responses are achievable). In brake control systems, this is a severe problema for two reasons: the instabilities induced from loss of tyre adherence and the crucial time delays in the the vehicle communication bus. These problems are alliviated if the integral value is reset to zero (thus the name reset control) at adequate instants. A well-designed reset controller is able to overcome the performance of conventional brake controllers.
Main advantages of its use
- Improves performance and robustness simultaneously
- It decreases the braking distance while maintaining as far as possible the driving characteristics of the vehicle
- It improves the estimation of the maximum friction between tire and road
- It is robust against changes in the road conditions and technological limitations such as model uncertainties, actuator saturation and bus time delay.
- It prevents locks and unstable slips
- Applications: Implementation of Wheel slip reset controllers in Brake systems with electromechanical brake actuators and a brake-by-wire system.
- Industrial partners involved in technological advances in automotive, road and aeronautics vehicles.
- The wheel slip controller can be used for several high level control modules, such as anti-lock braking systems (ABS), anti-slip systems, traction control (TC), vehicle stability control (VSC), electronic stability protocol (ESP) and advanced driver assistance systems (ADAS), among others.