Trajectory tracking control and impedance control of mine detection robot

Two topics about mine detection robot are described in this paper. First, we propose a trajectory tracking control algorithm based on RTK-GPS for hexapod robot. In extreme environment, for example a mine field, it is necessary for robot to observe the position and follow the reference trajectory. So we constructed a hierarchical control system including the high and low authority controllers. The low authority controller is sliding mode controller that is useful for robot system which contains the nonlinear characteristics at the drive system. And the high authority controller changes the gait by using GPS data. Next, we propose a foot control by using non-contact impedance control (NCIC) when hexapod robot acts on mine avoidance. NCIC can regulate virtual impedance between the end-effector and external objects using position information. First, a controller put a virtual column on a mine position by using GPS data and potentiometer. The virtual force is calculated from the non-contact impedance and the foot can avoid the mine position owing to revise base reference. We have already verified the usefulness of these schemes by simulation and experiments.