Case study on the act-and-wait concept for the control of periodic robot motions with feedback delay

Control of periodic motions of robots with feedback delay in the control loop is investigated. A case study of the PD control of a single block of mass is consid- ered with a given desired motion of the block. Two control concepts are applied: the traditional controller with con- stant feedback gains, and the act-and-wait controller, where the feedback gains are periodically switched on and off. First, the stability analysis of the variational system around the desired path is performed, then the response of the sys- tem for a sinusoidal desired motion with various periods is analyzed. It is shown that if the period of the desired motion is large enough, then the act-and-wait controller provides better response of the system than the traditional controller.