Steering control of long articulated vehicles using control allocation

Abstract

The aim of this paper is to investigate the steering control of long articulated vehicles using control allocation. Due to the complexity of the nonlinear equations of long articulated vehicles, a simplified model is used to design the controller at the upper and lower levels using sliding mode control and control allocation, respectively. At the upper level, an adaptive sliding mode controller is designed so that the state variables track their desired values, and at the lower level, control allocation distributes the control inputs among the actuators. To obtain the updated state variables of the long articulated vehicle, the control signals are applied to the vehicle model in TruckSim software. Then, the state variables are sent to the upper-level controller at each step. Since the system is underactuated, the weighted pseudo-inverse method of control allocation is used to determine the actuator inputs. The optimum weight coefficients are determined by minimizing the cost function using the PSO algorithm. The main innovation is the implementation of an adaptive sliding mode steering controller combined with a PSO-optimized weighted pseudo-inverse control allocation for an underactuated B-double vehicle, and the verification of the proposed scheme using a high-fidelity TruckSim–MATLAB/Simulink co-simulation model. Finally, the system stability is investigated during four manoeuvres, including step-steer and lane-change manoeuvres under wet and dry road conditions, which demonstrates acceptable performance. Considering the stability improvement of a B-double articulated vehicle, it is expected that this method can be effective for other long articulated vehicles as well.