Design of a parallel-type gripper powered by pneumatic actuators

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.

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