Tip-contact Force Control of One-link Flexible Manipulator: an Inherent Performance Limitation

It is well known that it is a very difficult task to control the interaction force of a robot manipulator with its environment. Much research has been done to identify and to understand the causes of this dfficulty. In this paper, an inherent limitation on the achievable bandwidth of force control is pointed out, which is due to the structural flexibility of the manipulator linkage and non-colocation of the manipulator actuators with the contact position of the manipulator with its environment. The limitation is inherent in the sense that it is independent of both controller design and the hardwares (actuators, sensors and computer etc.) used for implementation. To alleviating or eliminating this bandwidth limitation, it is necessary to relocate the actuator or/and add extra actuators.