Finite-time position/force control for flexible joint manipulators

For the problem of position and force trajectory tracking of flexible joint manipulators whose motion is constrained in the end, a finite-time position/force control strategy is proposed using adaptive terminal sliding mode. Firstly, position control and force control are decoupled according to the coordinate transformation and a reduced dynamic model for the manipulator is obtained. Then a new terminal sliding mode is established and an adaptive position/force control law is designed to overcome the uncertainties of the dynamic model. The system variables can be driven to reach the terminal sliding mode and slide to equilibrium point along the mode in finite time. Unlike previous position/force control strategies, this strategy can make both position and force tracking errors of the manipulator converge to zero in finite time. Simulation results are presented to validate the proposed method.