Robot Gripper

Robot gripper compliant with environmental constraints via force vector control of a four-bar linkage

This technology performs a pinch-grip motion with the fingertips by transmitting rotational torque from the drive unit through a four-bar linkage and connecting links. By adjusting the link length ratios of the four-bar mechanism, it controls the force vector direction applied to the fingertips, allowing the robot gripper to adapt to external environmental constraints, such as a table surface.

Conventional grippers often fail to account for collisions between the fingertips and environmental obstacles, such as tables, during pinch-gripping, which limits their ability to stably grasp small objects.

This technology configures the length ratios of the four-bar linkage (input, output, intermediate, and frame links) so that the force vector applied to the fingertips acts in a direction that lifts or lowers the object. Additionally, it incorporates a parallelogram linkage to maintain the fingertip angle and utilizes an elastic member and stopper between the output link and the frame link to ensure adaptive grasping. Suitable for logistics picking, precision assembly, and service robots, it enables stable grasping of small objects without colliding with surrounding constraints like tables.

‍

‍

Key Features:

• A third link, where the other end in the longitudinal direction is connected to the axis where the first and second links are joint-coupled, and is provided integrally with the second link in a 'V' shape.
• A robot gripper comprising a fifth link that is joint-coupled to the other longitudinal end of the fourth link, with its own other longitudinal end connected to the fingertip.
• An output link that faces the input link, with one longitudinal end connected to one longitudinal end of the connecting link.
• An intermediate link connected between the other longitudinal end of the input link and the other longitudinal end of the output link.

‍

This invention was developed with support from the Ministry of Science and ICT for the development of biomimetic bionic arm mechanisms.