Compliant Gripper with Push-Pull Assemblies for Unstructured Handling
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Solution Overview
Problem
Designing grippers for unstructured or semi-structured environments is challenging due to the need to handle objects with varying characteristics such as size, weight, and material type, requiring complex design constraints that are not easily met by existing general-purpose grippers.
Innovation Solution
A compliant gripper with two push-pull assemblies and compliant jaws that can conform to objects, using a stiff wire actuated by a linear actuator to maximize contact and grip without applying excessive force, allowing for secure handling of both hard and soft items without sensors to govern the gripping action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a general-purpose gripper is designed to handle objects with varying characteristics, then the gripper must accommodate diverse object properties, but the design complexity increases significantly
Solution Approach 1:
The gripper jaw is designed with compliant material properties that allow it to change its physical state and conform to different object geometries. The compliant jaw can elastically deform to match the contours of various objects, enabling a single gripper design to handle diverse object characteristics without increasing overall system complexity
Solution Approach 2:
The compliant jaw automatically adapts to the object's shape through its inherent material compliance without requiring external sensing or active control systems. The jaw's elastic properties enable it to self-conform to the gripped object, eliminating the need for complex sensors and control algorithms that would otherwise be required to achieve similar adaptability
2Force
If a gripper applies sufficient force to securely grip objects, then the gripping action is strong, but soft or fragile objects may be damaged
Solution Approach 1:
The compliant jaw's elastic modulus and stiffness are specifically selected to allow controlled deformation under load. This enables the jaw to yield to soft or fragile objects, distributing gripping force over a larger contact area and reducing peak stresses that would cause damage, while still maintaining sufficient overall grip strength
Solution Approach 2:
The compliant material inherently provides cushioning effect before contact is made, as the jaw begins to deform elastically upon approach. This pre-cushioning prevents sudden impact forces and allows gradual force application, protecting fragile objects from shock and excessive stress during the gripping action
3Measurement precision
If sensors are added to govern gripping action for different objects, then gripping precision improves, but device complexity and cost increase
Solution Approach 1:
The compliant jaw serves its own sensing function by physically conforming to the object's geometry. The deformation pattern of the compliant material inherently encodes information about the object's shape and properties, eliminating the need for separate sensors while still achieving precise adaptation to the gripped object
Solution Approach 2:
The compliant jaw material acts as an intermediary between the actuation mechanism and the object. It translates simple actuation movements into complex adaptive gripping motions, mediating the interaction between the simple actuator and diverse objects without requiring complex control systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compliant gripper effectively grips and manipulates objects with varying degrees of structural integrity, reducing design complexity and cost while ensuring durability and versatility in unstructured environments, as demonstrated by its ability to handle different items with consistent gripping actions.
Implementation Method 1
the term compliant refers to the tendency of a structure to undergo elastic deformation when subjected to an applied force
Implementation Method 2
The push-pull assemblies can be connected to an actuator such that they can be pushed when it is time for the gripper to shut and pulled back when it is time for the gripper to open
Implementation Method 3
maximize contact on the grip target with a high friction surface of the gripper
Data Source
AI summary
Grippers, such as robotic grippers, and associated methods and systems are disclosed herein. One disclosed gripper includes a first compliant gripper jaw, a first push-pull assembly having a first distal end fixed on the first compliant gripper jaw, a second compliant gripper jaw, a second push-pull assembly having a second distal end fixed on the second compliant gripper jaw, and an actuator connected to both the first push-pull assembly and the second push-pull assembly.