Adaptive Back-stepping Control of Cross-domain Robot on Water Surface and Ground Environment

This paper designs a cross-domain robot (CDR) to meet the working requirements in water, land, and air environments. In order to make the robot as compact as possible, a wheel-paddle integrated design is used to realize the multiplex of drive unit in the ground and on the water surface. The robot works in different environments, so the controller which just has ability to suit single environment may not have good performance. Therefore, an adaptive controller is designed, of which control algorithm takes the ground model of CDR as the reference model, adaptively estimates the power loss coefficient when the robot works on the water surface, and dynamically adjusts the output torque of the robot. This approach does not need to design two different controllers and avoids jitter during the CDR transition between the ground and the water surface. To obtain the actual resistance of the water surface motion, a first-order extended state observer (ESO) is used. The simulation results show that the proposed control algorithm can realize the adaptive control of the CDR in the water-land environment and can effectively suppress the influence of uncertain environmental disturbance.