Braking Control of Mobile Robots Using Integral Sliding-Mode Algorithm with Composite Convergence Regulation

With the continuous expansion of the application field of mobile robots, the diversification and complexity of the application scenarios have put forward higher requirements for their motion control performance. In order to enhance the ability to brake fast and to prevent slipping when the mobile robot is working, a slipping ratio tracking strategy based on an improved integral sliding mode algorithm regulated by a composite convergence law is proposed. The composite convergence law is proposed by integrating the power law with the exponential convergence law. A mathematical model of a single-wheeled mobile robot is established, a relationship curve between slipping ratio and pavement adhesion coefficient is introduced to estimate the pavement adhesion coefficient, and an improved integral sliding mode controller is designed. The stability is verified using Lyapunov stability theory. The slipping ratio is tracked based on the integral sliding-mode controller, and the slipping ratio is corrected to control the wheel slipping ratio near the ideal optimal slipping ratio. Furthermore, simulation experiments are conducted in MATLAB/Simulink (R2020b) under two typical working conditions to compare the proposed control strategy with conventional sliding-mode control regulated by an exponential convergence law. Finally, the mobile robot slipping ratio tracking experiments are conducted to verify the simulation results, which show that the proposed control strategy enables the mobile robot to reach the ideal braking state more quickly and stably, thereby improving the braking effect of the ABS braking system of the mobile robots.