Towards Hybrid Gait Obstacle Avoidance for a Six Wheel-Legged Robot with Payload Transportation

This paper investigates a novel hybrid gait obstacle-avoidance control strategy based on a perception system for the six wheel-legged robot (BIT-6NAZA) in uneven terrain. This robot has stronger payload transportation performance benefited from the flexibility of the 6-degree of freedom Stewart platform. It can guarantee the attitude level stability when passing through different shapes of obstacles. Firstly, the motion state matrix and gait unit of the BIT-6NAZA robot are considered. Moreover, the current local terrain is identified by the visual perception system. Then the wheel-legged hybrid gait types and parameters are selected according to the terrain detection. The gait topology matrix and gait planning matrix are generated for each leg controller to realize the wheel-legged hybrid obstacle-avoidance. In addition, a feedback controller combined with the posture sensor and foot-end force sensor is utilized to maintain the robot body. Finally, some demonstrations using the developed BIT-6NAZA robot are carried out. The performance illustrates the effectiveness and feasibility of the hybrid gait obstacle-avoidance control strategy.