A wheel slip controller is developed and experimentally tested in a car equipped with electromechanical brake actuators and a brake-by-wire ABS system. A gain scheduling approach is taken, where the vehicle speed is viewed as a slowly time-varying parameter and the model is linearized about the nominal wheel slip. Gain matrices for the different operating conditions are designed using an LQR approach. The stability and robustness of the controller are demonstrated via Lyapunov theory, frequency analysis and experiments using a test vehicle.

Abstract

Optimal feedback solutions to the in nite horizon LQR problem with state and input constraints based on receding horizon real-time quadratic programming are well known. In this paper we develop an explicit solution to the same problem, eliminating the need for realtime optimization. A suboptimal strategy, based on a suboptimal choice of a nite horizon and imposing additional limitations on the allowed switching between active constraint sets on the horizon, is suggested in order to address the computer memory and processing capacity requirements of the explicit solution. It is shown that the resulting feedback controller is piecewise linear, and the piecewise linear structure is explored and exploited for computational analysis of stability and performance of the suboptimal constrained LQR. The piecewise linear structure can also be exploited for e cient real-time implementation of the controller.

The application of gain-scheduled control to a pilot-scale solar power plant is described. A eld of parabolic collectors focus the solar radiation onto a tube where oil is pumped through in order to collect the solar power. The control problem is to keep the temperature of the oil leaving the eld at its desired value by manipulating the oil pump ow rate. It is shown that gain-scheduling can e ectively handle the plant nonlinearities, using high-order local linear ARX models that form the basis for the design of local linear controllers using pole placement.

No abstract

The ABS control problem is described, with a discussion on relevant h ybrid control aspects. Next, we comment o n conventional ABS design methods and present some new ideas and results on model-based ABS control design that relies on elements of hybrid control.

A wheel slip controller for Anti-lock Brake Systems (ABS) is designed using LQ-optimal control. The controller gain matrices are gain scheduled on the vehicle speed. A parameter dependent Lyapunov function for the nominal linear parameter varying (LPV) closed loop system is found by solving a linear matrix inequality (LMI) problem. This Lyapunov function is used to investigate robustness with respect to uncertainty in the road/tyre friction characteristic. Experimental results from a test vehicle with electromechanical brake actuators and brake-by-wire show that high performance and robustness are achieved.

Norway is currently the largest market in the world for electric vehicles compared to the total number of vehicles sold, and there is also a political goal in Norway to stop the sale of new conventional cars 1 by 2025. Changing to nonemission transport can result in approx. 1.5 mill. private electric vehicles in 2030, resulting in an energy need of 4 TWh, which represents an increase of 3% of the Norwegian electricity consumption. The increased number of electric vehicles will not be an energy problem, but it can be a capacity related problem in the distribution grid if all households are charging at the same time -in addition to their usual consumption of electricity. This paper presents results from a research project evaluating the consequences of the increasing share of electric vehicles and the potential for demand response and flexibility in charging. Results are based on a survey performed among households with electric vehicles and meter data of the energy consumption from charging of a selection of the most common electrical vehicles in Norway.