A study of path errors due to servo dynamics and link flexibilities in a two-coordinate robotic manipulator

Path errors in a two-coordinate polar manipulator, caused by the dynamics of the servo drives and by flexibilities of the driven members, are studied by means of time domain computer simulations. It is shown that velocity lags in the servo responses can introduce path errors even if the flexibilities in the driven members can be corrected. A feedforward control algorithm, that conditions the position command signal with corrective terms, is shown to compensate for the deflections caused by both structural flexibilities and the servo dynamics