Versatile Telescopic-Wheeled-Legged Locomotion of Tachyon 3 via Full-Centroidal Nonlinear Model Predictive Control

Sony Global Manufacturing & Operations Corporation, Minato-ku, Tokyo, Japan, 108-0075 Abstract: This paper presents a nonlinear model predictive control (NMPC) toward versatile motion generation for the telescopic-wheeled-legged robot Tachyon 3, the unique hardware structure of which poses challenges in control and motion planning. We apply the full-centroidal NMPC formulation with dedicated constraints that can capture the accurate kinematics and dynamics of Tachyon 3. We have developed a control pipeline that includes an internal state integrator to apply NMPC to Tachyon 3, the actuators of which employ high-gain positioncontrollers. We conducted simulation and hardware experiments on the perceptive locomotion of Tachyon 3 over structured terrains and demonstrated that the proposed method can achieve smooth and dynamic motion generation under harsh physical and environmental constraints. Keywords: Robotics, Real-Time Implementation of Model Predictive Control 1. INTRODUCTION Legged robots are promising robotic mobilities that can Moreover, they can lack safety, e.g., cause catastrophic damage to the robot itself and to the environment when Figure 1. Hardware structure of telescopic-wheeled-legged they fall.