Pressure-Sensing Robot Gripper Posture Control Against Slippage

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Solution Overview

Problem

Robotic devices face challenges in gripping and transporting workpieces due to slippage caused by the weight, shape, or surface state, leading to potential falls.

Innovation Solution

A robotic device equipped with an end effector having two fingers and a pressure distribution sensor that detects pressure variations, enabling posture control through rotation to prevent slippage by adjusting the gripping force and position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gripping force is increased to prevent slippage, then reliability of workpiece holding is improved, but risk of damaging the workpiece increases

Engineering Contradiction:

Improveworkpiece holding reliabilityVSAvoidworkpiece damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by distributing gripping force non-uniformly across the contact surface. The pressure distribution sensor detects local pressure variations, and the controller adjusts gripping force locally through finger posture control, applying higher force only where needed to prevent slippage while maintaining lower force in other areas to avoid damage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by continuously monitoring pressure distribution during gripping and dynamically adjusting the end effector's posture and gripping force in real-time. This allows the system to adapt to varying workpiece characteristics and maintain optimal gripping force that prevents slippage without causing damage.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If pressure distribution sensing is implemented, then gripping control precision is improved, but device complexity increases

Engineering Contradiction:

Improvepressure distribution detection precisionVSAvoidsensor and control system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by using the pressure distribution sensor for multiple functions: detecting workpiece presence, measuring pressure distribution, identifying workpiece characteristics, and providing feedback for control adjustments. This multi-functionality justifies the added complexity by eliminating the need for separate sensing systems for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback by using the pressure distribution sensor to continuously monitor gripping conditions and feeding this information back to the controller, which adjusts the end effector's posture and gripping force accordingly. This closed-loop feedback system improves gripping precision while managing complexity through intelligent control algorithms.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If end effector rotation is performed for posture control, then adaptability to different workpiece orientations is improved, but control complexity increases

Engineering Contradiction:

Improveworkpiece orientation adaptabilityVSAvoidposture control complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing posture control adjustments before slippage occurs. The pressure distribution sensor detects potential slippage conditions in advance, and the controller proactively adjusts the end effector's orientation and gripping force to prevent slippage, rather than reacting after the problem occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical adjustment mechanisms with sensor-based detection and control algorithms. Instead of using multiple mechanical actuators to adjust gripping posture, the system uses pressure distribution sensing combined with rotational control of the end effector, simplifying the mechanical structure while maintaining adaptability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Effectively prevents workpiece slippage and falls by dynamically adjusting the gripping force and position based on real-time pressure distribution data, ensuring secure handling and transport.

Implementation Method 1

a pressure distribution sensor that detects pressure variations

Methodology Applied

Scientific EffectPressure distribution detection: Pressure Increase

Data Source

PatentUS11325248B2Robotic device and gripping method

Publication Date: 2022.05.10 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A robotic device includes an end effector device, a first sensor, and a controller. The end effector device includes two fingers for gripping a workpiece. The first sensor detects a pressure distribution on a gripping position on the workpiece by the two fingers. The controller performs, based on a temporal variation in the pressure distribution when the workpiece is lifted, posture control including rotation of the end effector device.