Model predictive steering control for independent driving and steering vehicles considering coaxial steering mechanism — Implementation to an embedded CPU

Omnidirectional vehicles with independent driving and steering wheels are useful since they can move with arbitrary attitude and change the moving direction rapidly. However, excessively rapid steering and unacceptable load may damage mechanisms. To prevent rapid steering and overloads, low-pass filter (LPF) is applied to the steering signals. Since the angular velocity should be limited on account of the motor constraint, even if the time constant is set small, the convergence of the steering is slow, and the error between the target angle and the real steering angle may occur. In this study, we propose the model predictive steering control for independent four-wheel driving and steering vehicles with coaxial steering mechanisms. The proposed method can consider physical constraints of actuators and achieve smooth and quick convergence of the steering to the target angle. We verify the efficiency of the proposed method by experiments using the vehicle which is equipped with an embedded CPU.