Underactuated Robotic Gripper With Adhesion for Adaptive Prehension
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Solution Overview
Problem
Existing end-effectors for robots face challenges in satisfying contradictory requirements of being small, light, strong, and durable while effectively grasping items of varying geometries, particularly in unstructured environments.
Innovation Solution
The development of underactuated end-effectors with fewer actuators than degrees-of-freedom, featuring compliant joints and springs that allow adaptive grasping, combined with adhesion grippers like vacuum or electrostatic grippers, and a system that processes tactile sensor data to enhance prehension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional actuators are used to control each degree of freedom in end-effectors, then precise control is achieved, but the device becomes heavy and complex
Solution Approach 1:
The patent combines multiple actuation functions into a single tendon-driven mechanism. A single actuator controls multiple degrees of freedom through carefully designed tendon routing and pulley systems, allowing coordinated finger movements to be achieved with one actuator rather than multiple independent actuators for each degree of freedom.
Solution Approach 2:
The tendon-driven mechanism serves multiple functions simultaneously: it provides actuation force, controls multiple joints, enables adaptive grasping, and allows passive compliance. The same tendon system that actuates the fingers also enables passive adaptation to object geometry through elastic elements and compliant mechanisms.
2Adaptability or versatility
If more actuators are added to increase grasping capability, then adaptability improves, but weight and complexity increase
Solution Approach 1:
The end-effector employs passive adaptive mechanisms that automatically adjust to object geometry without active control. Elastic elements, compliant joints, and the tendon routing geometry enable the fingers to naturally conform to the shape and size of grasped objects, providing adaptability without additional actuators or complex control systems.
Solution Approach 2:
The system transitions from static, rigid actuation to dynamic, compliant actuation. The tendon-driven mechanism with elastic elements allows the end-effector to dynamically adapt its configuration during grasping, enabling smooth transitions between different grasp types and automatic adjustment to varying object geometries.
3Strength
If rigid structures are used for strength, then durability improves, but adaptability to varying geometries deteriorates
Solution Approach 1:
The patent employs compliant mechanisms and flexible structural elements that can deform and adapt to object geometry while maintaining sufficient structural strength. The finger links incorporate compliant joints and elastic elements that allow bending and shaping during grasping, enabling the rigid-looking structure to become flexible and adaptive when needed.
Solution Approach 2:
The end-effector combines rigid and compliant materials in a composite structure. High-strength materials provide the necessary structural framework and load-bearing capacity, while compliant materials and elastic elements are strategically placed to enable adaptation and passive compliance, creating a hybrid structure that achieves both strength and flexibility.
Data Source
AI summary
An end-effector may include a base, a plurality of underactuated fingers coupled to the base; and an adhesion gripper coupled to the base. An end-effector may include a base, an actuator, a first underactuated finger comprising a proximal link and a distal link, the proximal link including a distal end, a guide for a first tendon spaced a first distance away from the distal end of the proximal link and the distal link including a lever arm disposed on a proximal side to the distal pad and which extends in a volar direction from a first axis, and a node disposed on the lever arm sized and shaped to receive a first tendon. The end-effector may include a first revolute joint compliant in a first direction disposed between the base and the proximal link; and a second revolute joint compliant in the first direction disposed between the proximal link and the distal link.