Compression braking control for heavy-duty vehicles

Modern heavy-duty vehicles are equipped with a compression braking mechanism that augments their braking capability and reduces the wear of the conventional friction brakes. We consider a vehicle speed control problem using a continuously variable compression braking mechanism. The variability of the compression brake is achieved through the control of the brake valve of the vehicle´s turbocharged diesel engine. An adaptive controller is designed to ensure good speed tracking performance in brake-by-wire, or vehicle-following, driving scenarios even during large variations in mass and road grade. Our approach is to first consider the model without compression brake actuator dynamics and derive a model reference adaptive controller using the speed-gradient procedure. Then, the actuator dynamics are included in the design via the use of the backstepping procedure. The backstepping controller is implemented with a simplified numerical differentiator-based approximation