Coordinated Motion Control and Event-based Obstacle-crossing for Four Wheel-leg Independent Motor-driven Robotic System via MPC

TL;DR

This paper introduces an MPC-based coordinated motion control and obstacle-crossing strategy for a four wheel-leg robotic system, utilizing event-triggering to optimize resource use and validated through simulations and physical experiments.

Contribution

It presents a novel MPC approach with event-triggering for wheel-leg robots, incorporating a dynamic model and tire characteristics to improve obstacle crossing capabilities.

Findings

Successful simulation and physical prototype validation

Efficient resource and energy use due to event-triggering

Enhanced obstacle-crossing performance

Abstract

This work presents the coordinated motion control and obstacle-crossing problem for the four wheel-leg independent motor-driven robotic systems via a model predictive control (MPC) approach based on an event-triggering mechanism. The modeling of a wheel-leg robotic control system with a dynamic supporting polygon is organized. The system dynamic model is 3 degrees of freedom (DOF) ignoring the pitch, roll and vertical motions. The single wheel dynamic is analyzed considering the characteristics of motor-driven and the Burckhardt nonlinear tire model. As a result, an over-actuated predictive model is proposed with the motor torques as inputs and the system states as outputs. As the supporting polygon is only adjusted at certain conditions, an event-based triggering mechanism is designed to save hardware resources and energy. The MPC controller is evaluated on a virtual prototype as well as a physical prototype. The simulation results guide the parameter tuning for the controller implementation in the physical prototype. The experimental results on these two prototypes verify the efficiency of the proposed approach.