A real-time network based bilateral robot control with prioritized transfer of state variables

This paper proposes a prioritization scheme of the control state variables transmitted via a computer network, considering time delay. The robustness of each state variable against time delay is evaluated, and then the priority order is assigned. The priority based data transfer is implemented on a real-time network system by a device named Responsive Processor. The network system is applied to a bilateral robot system, which is driven by a controller based on impedance matching theory. The control algorithm employs an adaptive hybrid control method, which adjusts the hybrid combination ratio of position control and force control depending on the variation of the remote environment. Experiments were conducted to evaluate the priority assignment. Various combinations of the time delay and state variables were set up. The results conducted to the different stiffness objects, verified the effectiveness of priority assignment and supported the analytical results.