Robot Gripper with Coupled Joints for Straight Finger Path

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Solution Overview

Problem

Existing robot grippers lack a robust mechanical structure that allows for efficient and precise movement of gripper fingers without changing orientation, which is essential for reliable object handling and manipulation in industrial and cooperative robotics.

Innovation Solution

A robot gripper design featuring a gripper base body with a base member and intermediate member connected via pivot joints, and a finger carrier with a gripper finger mounted via a third pivot joint, utilizing specific gear ratios and coupling devices to achieve a straight path movement of the gripper finger without altering its orientation, enabled by a single drive motor that adjusts all pivot joints simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple independent drives are used to control gripper fingers, then movement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemovement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple drive functions into a single drive mechanism that simultaneously controls multiple rotary joints through a unified drive train with coupled rotation axes, reducing the number of independent drives while maintaining coordinated movement precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single drive mechanism is designed to perform multiple functions by controlling different rotary joints through a multi-axis coupling system, allowing one drive to accomplish what would traditionally require multiple separate drives

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If gripper finger orientation changes during movement, then adaptability is improved, but control precision deteriorates

Engineering Contradiction:
ImproveadaptabilityVSAvoidcontrol precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The gripper mechanism is segmented into multiple rotary joints with specific coupling relationships, where the first, second, and third rotary joints are coupled such that their combined motion produces linear finger movement while maintaining constant orientation through geometric constraint

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If multiple rotary joints are used to achieve linear movement, then movement precision is improved, but mechanical robustness deteriorates

Engineering Contradiction:
Improvemovement precisionVSAvoidmechanical robustness
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

Multiple rotary joints are merged into a unified drive train with coupled rotation axes, where the first rotary joint is coupled to the second rotary joint, and the second is coupled to the third, creating a mechanically robust single-degree-of-freedom system that achieves linear movement through coordinated rotation

Inventive Principle:
Principle #5Merging (Combining)

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

This design results in a mechanically robust gripper capable of simple open/close movements with a single degree of freedom, allowing for high closing forces and precise control, enhancing the reliability and safety of human-robot cooperation by preventing unintentional collisions and ensuring robust gripper performance.

Implementation Method 1

the first rotary joint is coupled to the second rotary joint by a first coupling device in a defined first gear ratio of 1 to minus 2, and the second rotary joint is coupled to the third rotary joint by a second coupling device in a defined second gear ratio of 2 to minus 1

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

a drive motor for moving the first gripper finger, which is configured to move the first gripper finger by simultaneously adjusting the first rotary joint, the second rotary joint, and the third rotary joint

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3341165B1Robot gripper
Publication Date: 2019.07.17 KUKA DEUT GMBH
  • EP3341165B1 patent drawingFigure 1
  • EP3341165B1 patent drawingFigure 2
  • EP3341165B1 patent drawingFigure 3

AI summary

The invention relates to a robot gripper (11) comprising a main gripper body (12), a base element (14) mounted by a first rotational joint (15.1), and an intermediate element (18) mounted by a second rotational joint (15.2) about a second rotational axis (D2); and also comprising a finger carrier (17) carrying a first gripper finger (16.1) and mounted by a third rotational joint (15.3), wherein the robot gripper (11) comprises a drive motor (M) that moves said first gripper finger (16.1) and is designed to move said first gripper finger (16.1) by simultaneously adjusting the first rotational joint (15.1), the second rotational joint (15.2) and the third rotational joint (15.3).