Preshaped trajectory command for fast repetitive PTP motion of PD-controlled flexible joint manipulators

Abstract

For PD-controlled industrial robot manipulators performing point-to-point (PTP) motion, the effect of joint flexibility grows as the cycle time for the PTP motion increases. To reduce residual vibration induced by joint flexibility, a method of generating preshaped reference trajectory command is proposed. This preshaped reference trajectory command is developed from the given PTP motion and the parameters of given PD controller. Simulations show that low overshoot and short settling time in fast PTP motion is achieved by applying the preshaped trajectory reference command, without excessive control effort. This proposed method is readily applicable to PD-controlled industrial robots which perform repetitive fast PTP motions.