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An unified compliant control algorithm to regulate the force by dual arms is proposed, where two arms are treated as one arm in a kinematic viewpoint. The force error calculated from the information of two force/torque sensors attached to the end of each arm is transferred to minimum actuator coordinates, and then distributed it to total system actuator coordinates. The position adjustment at the total actuator coordinates is computed based on the effective compliance matrix with respect to the total actuator coordinates, which is obtained by coordinate transformation between the task coordinates and the total actuator coordinates. An experiment is carried out for dual arms with asymmetric kinematic structure to control an interaction force between manipulators and the environment. The performances of the proposed control algorithm are experimentally compared to that of dual arms employing a master/slave scheme. The proposed compliant control algorithm not only outperforms other algorithms, but also can be treated as an unified approach in the sense that it can be applied to arbitrary dual arm systems with general kinematic structures.

In this work, a parallel-type gripping and micro-positioning mechanism is proposed. This device has a parallelogrammatic platform which can be flexibly folded. Therefore, this mechanism not only can be used to grasp an object having irregular shape or large volume, but also can be utilized as a micro-positioning device after grasping the object. Configuration parameter for configuration control of the proposed gripping mechanism is defined. Grasping force and isotropic characteristic of the mechanism are considered as design indices for optimal design of the gripping mechanism. The proposed mechanism is expected to be used as an adaptable gripping and micro-positioning device by attaching it at the end-point of a robot.

A new parallel gripping mechanism is proposed in this work. This device has a parallelogramic platform which can be flexibly folded. Therefore, this mechanism not only can be used to grasp an object having irregular shape or large volume, but also can be utilized as micro-positioning device after grasping the object. Forward position analysis and platform kinematics are investigated to deal with motion tracking and force control. Pneumatic rotator is employed for actuation and a compact sized, 4/3 way proportional pressure valve is also developed to deal with feedback-based dynamic control. The pressure valve also allows indirect force control by measuring the offset pressure occurring due to contact between the grasped object and the parallel platform. In experimental work, performances of the motion tracking and indirect force control are shown satisfactory.