Robot Gripper Stability Control Using Contact and Object Data

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Solution Overview

Problem

Handling robots face challenges in gripping objects stably, particularly due to insufficient grip force and uncertainty in object contact, leading to instability during transfer and placement.

Innovation Solution

A hand system comprising a gripper, driver, and controller that estimates stability based on contact and characteristic information, performing specific motions to increase grip stability, including a first motion when stability is low and a second motion when stability cannot be estimated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gripper applies insufficient grip force, then the device complexity is reduced, but the stability of gripping deteriorates

Engineering Contradiction:

Improvestability of grippingVSAvoidcontrol complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system employs feedback control by continuously monitoring contact information between the gripper and object, estimating stability based on this contact data, and adjusting the grip force accordingly. The controller modifies the driver's output based on the estimated stability to maintain optimal gripping conditions without excessive complexity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment by automatically estimating stability from contact information and autonomously determining the appropriate grip force modifications. The controller uses the estimated stability to command the driver, creating a self-regulating system that maintains stable gripping without external intervention.

Inventive Principle:

Principle #25Self-service

2Reliability

If the gripper performs multiple adjustment motions to increase stability, then the stability of gripping is improved, but the loss of time increases

Engineering Contradiction:

Improvestability of grippingVSAvoidtime for grip adjustment

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary stability estimation using contact information acquired during the approach phase, before actual gripping occurs. By estimating stability in advance and pre-adjusting the grip force, the system avoids time-consuming adjustments after contact is established, thus reducing overall task time while maintaining stability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces iterative mechanical trial-and-adjustment processes with a computational stability estimation approach. By using contact information and stability algorithms to determine the optimal grip force directly, the system eliminates the need for multiple mechanical adjustment cycles, significantly reducing adjustment time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240139973A1Hand, handling robot, control device, method for controlling hand, and storage medium

Publication Date: 2024.05.02 KK TOSHIBA

AI summary

According to one embodiment, a hand includes a gripper, a driver, and a controller. The gripper is configured to grip an object. The driver drives the gripper. When a stability when gripping the object is estimated, the controller causes the driver to perform a first motion to increase the stability. The stability is estimated based on contact information of the gripper for the object, and characteristic information including at least one of a size or a weight of the object.