Theoretical and experimental study on remote dynamic balance control for a suspended wheeled mobile manipulator

Dynamic balance of mobile robots is a challenging research because of its complex nonlinearity and dynamics. This study proposes a dynamic balance control (DBC) method to enhance the stability and presents a virtual control strategy that could help the operators manipulate the robot remotely. Considering vibration absorption, the robot employs semi-active suspension systems that are capable of reducing the vibration induced by rough terrain. But the systems aggravate unbalance when the robot starts/stops rapidly and the manipulator performs tasks after the robot locked onto a target. Aiming to minimize the unbalance, the DBC method is presented by combining the off-line input voltage shaping and real-time stability compensation. On the basis of it, through building the dynamic model of the robot, the unbalance can be eliminated by regulating the input voltage of motors installed in driving wheels and actuated joints. Further, for reducing the unbalance caused by external shock from the unevenness of pavement surface, the study seeks to apply the force-angle stability margin to measure the stability. For experimental study, the virtual reality technology is used to develop a visualized remote control system, which is realized by using WiMax to transmit the commands and remote desktop from the lower computer to upper computer. Finally, the proposed method is demonstrated on a suspended wheeled mobile manipulator by simulations and experiments.