Software/Hardware-Based Hierarchical Finite-Time Sliding-Mode Control With Input Saturation for an Omnidirectional Autonomous Mobile Robot

Abstract

To track the desired pose of the omnidirectional autonomous mobile robot (OAMR) in finite time, the finite-time virtual desired trajectory (FTVDT) is designed by the 1st sliding surface with the linear dynamics and fractional order of pose's tracking error. To track the FTVDT in finite time, the finite-time sliding-mode saturated control (FTSMSC) is designed by the second sliding surface with the linear dynamics and fractional order of the FTVDT's tracking error. In short, the proposed hierarchical finite-time sliding-mode control with input saturation (HFTSMCIS) contains the FTVDT and the FTSMSC. As compared with previous studies, the finite-time trajectory tracking with the reduced chattering control input is achieved by the suitable selection of control parameters. The HFTSMCIS algorithm is executed in the CPU, and then it is transformed to a PWM signal using FPGA hardware and the motor velocity is simultaneously decoded by the FPGA hardware for feedback control. In contrast, the other state signals are achieved from the mathematical model such that the feedback control system is simple and effective. It is so-called software/hardware-based HFTSMCIS (SHB-HFTSMCIS). Finally, three experiments, including two different process time and obstacle avoidance, are presented to validate the effectiveness and robustness of the proposed control system.

Keywords

• Omnidirectional autonomous mobile robot
• hierarchical control
• finite-time sliding-mode control
• FPGA
• input saturation
• Lyapunov stability theory