Attitude stability control for multi-agent six wheel-legged robot

Multi wheeled-legged robot systems are MIMO complex systems with multi information fusion. In this paper, a multi-sensor information fusion based wheeled-legged cooperative control strategy is proposed to solve the problem of attitude stability control for the six wheeled-legged robot- BIT-NAZA-II. First, when the robot is wheel motion, the overall attitude of the robot is adjusted by controlling the vertical degree of freedom(DOF) for the Stewart platform. Second, when the wheel movement is on uneven road, the foot end is easy to be suspended or raised. The impedance control method based on the position inner loop is used to solve the problem of leg suspension or raised. Third, in order to ensure the maximum motion space of single leg, the central height controller is designed. Moreover, the control strategy is mainly completed by the central CPU and six bottom CPUs. Six bottom CPUs receive the force information of each leg, and calculate the position of each leg by combining the impedance controller. Meanwhile, the central CPU receives the attitude angle information, calculates the position of each leg by using the attitude controller, takes two different position commands as the input of the central height controller, outputs the calculated position of the central height controller to six bottom CPUs through UPD communication, and the bottom CPU is used to calculate the variation of Stewart platform DOF. Finally, the experimental results of the control strategy in the six wheeled-legged robot system are given, and the feasibility and effectiveness of the control strategy are verified.