Direct-drive active compliant end effector (active RCC)

A fast, lightweight, active end-effector, which can be attached to the endpoint of a commercial robot manipulator, has been designed and built using an impedance-control method. This control method causes the end-effector to behave dynamically as a two-dimensional remote center compliance (RCC). The compliancy is in this active end-effector is electronic and can be modulated by an online computer. The device is planar and five-bar linkage, and is driven by two direct-drive, brushless DC motors. A two-dimensional, piezoelectric force cell on the endpoint of the device, two 12-bit encoders, and two tachometers on the motors form the measurement system. The high structural stiffness and light weight of the material used in the system allow for a 15-Hz-bandwidth impedance control