Direct-Drive Parallel-Kinematic Gripper for Fast Dexterous Grasping
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Solution Overview
Problem
Conventional robotic grippers with high gear-ratio worm screws are limited in speed and dexterity due to rigid clamping and reduced speed, making it difficult to handle fragile objects and react to environmental changes, and existing solutions like series-elastic actuation and strain gauges introduce additional drawbacks.
Innovation Solution
A robotic gripper with direct drive actuation using two motors and interconnected links, where the controller determines contact and grasping through angular displacement and load detection, and adjusts movement to maintain object retention while monitoring winding temperature to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a high gear-ratio worm screw is used to multiply motor torque, then gripping force is improved, but speed is reduced and the gripper becomes limited to rigid clamping
Solution Approach 1:
The patent replaces the traditional high gear-ratio worm screw mechanical transmission system with a direct-drive motor system. This substitution eliminates the gearbox that limited speed while maintaining the ability to generate sufficient gripping force through direct motor actuation, thereby resolving the contradiction between force multiplication and speed maintenance.
2Force
If a high gear-ratio worm screw is used for rigid clamping, then gripping force is improved, but dexterity and ability to handle fragile objects deteriorates
Solution Approach 1:
The direct-drive motor system replaces the rigid worm screw transmission, enabling the gripper to achieve both strong gripping force and high dexterity. The elimination of mechanical transmission components allows for more precise and adaptable control, improving the ability to handle fragile objects while maintaining gripping capability.
3Measurement precision
If series-elastic actuation and strain gauges are added to mitigate crashing, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The direct-drive motor system inherently provides the functionality previously requiring separate components. The motor's own control system detects contact through current feedback and angular displacement, eliminating the need for separate strain gauges and series-elastic elements. This self-service approach maintains high sensitivity while reducing overall device complexity.
4Reliability
If traditional force/torque sensors or contact sensors are used to detect table contact, then safety is improved, but device complexity and response time deteriorates
Solution Approach 1:
The motor control system uses the motor's own electrical characteristics (current, voltage, angular displacement) to detect contact with the table or object. This self-service detection method provides reliable contact sensing without requiring separate force/torque sensors or contact sensors, thereby reducing device complexity while maintaining safety and reliability.
Data Source
AI summary
A gripper includes at least one movable finger. Each movable finger includes a first motor, a second motor, a first motor link having a first end coupled to a rotor of the first motor, a second motor link having a first end coupled to a rotor of the second motor, a finger link having a first end in pivotal connection with a second end of the second motor link and a gripper pad, and a connecting link having a first end in pivotal connection with a second end of the first motor link and a second end in pivotal connection with the finger link. The gripper further includes at least one controller programmed or configured to actuate the first motor and the second motor of each of the at least one movable finger.