Gain Scheduling Fuzzy Sliding Mode Strategy for Robotic Motion Control

A Mitsubishi Movemaster RV-M2 robotic system control system is retrofitted into system-on-programmable-chip (SOPC) control structure. The software embedded in Altera Nios II field programmable gate array (FPGA) micro processor has the functions of using UART to communicate with PC, robotic inverse kinematics calculation, and robotic motion control. The digital hardware circuits with encoder decoding, limit switch detecting, pulse width modulation (PWM) generating functions are designed by using Verilog language. Since the robotic dynamics has complicate nonlinear behavior, it is impossible to design a MIMO model-based controller on micro-processor. Here a novel model-free fuzzy sliding mode control with gain scheduling strategy is developed to design the robotic joint controller. This fuzzy controller is easy to implement with 1D fuzzy control rule and less trial-and-error parameters searching work. The experimental results show that this intelligent controller can achieve quick transient response and precise steady state accuracy for industrial applications.