Compliant Underactuated Grasper Flexure Joints
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Solution Overview
Problem
Current robotic graspers face challenges in efficiently manipulating and grasping objects in structured or unstructured environments due to limited compliance and adaptability, often requiring more actuators than degrees of freedom, which hinders their ability to handle diverse objects effectively.
Innovation Solution
A compliant underactuated grasper design featuring a base and fingers with flexure joints of varying compliance, a tendon cable system, and a 'fingernail' mechanism, allowing for adaptive grasping and manipulation with fewer actuators than degrees of freedom, utilizing a combination of rigid and compliant materials for enhanced flexibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robotic grasper uses more actuators to increase degrees of freedom for better adaptability, then the adaptability improves, but the device complexity and cost increase
Solution Approach 1:
The grasper employs passive compliance mechanisms (flexure joints, compliant fingers) that automatically adapt to object geometry without requiring active control or additional actuators. The system serves itself by using elastic deformation and mechanical compliance to achieve adaptive grasping, eliminating the need for complex active adaptation systems
Solution Approach 2:
The invention changes the compliance parameters of the grasper structure through carefully designed flexure joints and compliant materials. By varying the stiffness and flexibility parameters of different components, the system achieves adaptability to different object shapes and sizes without adding actuators, resolving the contradiction between adaptability and complexity
2Adaptability or versatility
If the grasper uses compliant materials and flexure joints to improve adaptability, then the adaptability improves, but the structural stability may deteriorate
Solution Approach 1:
The grasper implements different compliance levels at different locations: highly compliant fingers and flexure joints for adaptability, while maintaining rigid structural elements (base, actuator mounting structures) for stability. This local differentiation allows the system to be compliant where needed and stable where required, resolving the contradiction between adaptability and structural stability
3Device complexity
If the grasper is underactuated with fewer actuators, then the device complexity reduces, but the control precision may worsen
Solution Approach 1:
The invention replaces active control mechanisms with passive mechanical compliance systems. Instead of using multiple actuators with complex control algorithms to achieve precise grasping, the system uses elastic deformation, flexure joint mechanics, and compliant material properties to automatically conform to and precisely position on objects, achieving control precision through mechanical design rather than active control
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 grasper achieves robust and adaptive grasping capabilities, enabling efficient manipulation of various objects by minimizing the number of actuators required, while maintaining stability and adaptability to different shapes and sizes, and can handle both fine manipulation and heavy lifting tasks.
Implementation Method 1
a flexure joint, the flexure joint having a first compliance in a first direction of the flexure joint and a second compliance in a second direction of the flexure joint
Data Source
AI summary
A compliant underactuated grasper includes a base and a plurality of fingers. At least one of the plurality of fingers includes: a proximal phalanx; a proximal joint connecting the proximal phalanx to the base; a distal phalanx; a distal joint connecting the distal phalanx to the proximal phalanx; and a member for moving the phalanges. At least one of the proximal joint and the distal joint includes a flexure joint having a first compliance in a first direction and a second compliance in a second direction, the second compliance being stiffer than the first compliance. The distal phalanx includes: a rounded end face; and a lifting portion including a lifting edge adjacent the rounded end face. The member acts in parallel to the first direction. The grasper further includes at least one actuator associated with the member. The grasper has fewer actuators than degrees of freedom.