Hybrid control of force and position without force sensor

The authors propose hybrid control of force and position without a force sensor. The proposed hybrid control system uses both the motion control method based on a H^∞ acceleration controller and a force control method based on the reaction force estimation system. This system uses a position sensor signal and an estimated value of reaction force, instead of the force sensor. The H^∞ acceleration controller realizes a fine and fast motion control. The proposed hybrid control was implemented in a three-degree-of-freedom direct drive robot manipulator. The test results are presented