Speed gradient approach to longitudinal control of heavy-duty vehicles equipped with variable compression brake

Abstract

This paper considers a longitudinal speed control problem for heavy-duty vehicles equipped with variable compression brake. The use of compression brake reduces the wear of the conventional friction brakes, and it is, thus, a preferred way of controlling the vehicle speed during a steady descent or noncritical braking maneuvers. To perform more aggressive (critical) braking maneuvers or control vehicle speed during large changes in the grade, the compression brake must be coordinated with gear ratio adjustments and friction brakes. In this paper we develop nonlinear controllers that accomplish both noncritical and critical maneuvers. We also show how distance constraints from other vehicles in traffic may be included. The design technique is based on the speed-gradient (SG) approach, whereby the control action is chosen in the maximum descent direction for a scalar goal function. The nominal goal function is selected to address the speed regulation objective and, then, it is appropriately modified by barrier functions to handle the critical maneuver requirements. Two ways to handle the uncertainty in the road grade are discussed: through the use of an integral action of the SG controller for constant (but unknown) grades, and through the use of an added differential action for varying grades.

Brake Valve Timing and Fuel Injection: a Unified Engine Torque Actuator for Heavy-Duty Vehicles

“…Speci®cally, the authors are using the model reference adaptive control (MRAC) approach in [14], and the speed gradient method in [16] to address the HDV speed regulating and tracking problems during large parameter deviations and unknown road conditions.…”

Adaptive model predictive control for co-ordination of compression and friction brakes in heavy duty vehicles

“…A detailed crank angle based model of such a continuous compression brake system is developed in Reference [5] and validated with experimental data from engine dynamometer. In Reference [6] a non-linear Lyapunov-based control design has been proposed for continuously variable compression braking system in longitudinal control; and a reference velocity governor which prevents the saturation of braking actuators. To compensate for large parameter variations typical to heavy vehicles, a model reference adaptive algorithm is proposed in Reference [7] which uses a continuous compression braking system.…”

“…To compensate for large parameter variations typical to heavy vehicles, a model reference adaptive algorithm is proposed in Reference [7] which uses a continuous compression braking system. So Reference [6] addresses possible actuator saturations and Reference [7] treats vehicle parameter variation. In this paper, we address both difficulties simultaneously.…”

Speed control experiments for commercial heavy vehicles with coordinated friction and engine compression brakes

“…We have previously studied the effects of continuously varying valve timing on vehicle response in [2,3,8,91. In [2], we have developed an adaptive controller that estimates the vehicle mass and road grade values and controls the continuously variable compression brake to ensure consistent and robust speed tracking performance in the face of unknown vehicle mass and significant road grade changes.…”