Robot Holding Brake Control for Collision Release

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Solution Overview

Problem

Robots equipped with holding brakes face challenges in safely navigating obstacles, as they can become trapped and fail to release clamping forces effectively, leading to potential collisions and inefficient operation.

Innovation Solution

A control system that monitors collisions and uses holding brakes to selectively open or delay their closure, allowing the robot to adjust its position and reduce clamping forces by actuating holding brakes for specified periods or based on detected axle loads, enabling the robot to avoid obstacles and maintain safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If holding brakes are engaged to stop or lock the robot axis during collision, then safety is improved, but the robot becomes trapped and cannot release clamping forces

Engineering Contradiction:
ImprovesafetyVSAvoidability to release clamping
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The holding brake control is made dynamic by allowing temporary reopening after initial engagement. The control device engages holding brakes upon collision detection, then temporarily reopens them after a predetermined time period if axle load indicates clamping, enabling the robot to release and move away from the obstacle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter of the holding brake from a static engaged state to a dynamically adjustable state. By monitoring axle load and time, the control device modifies the brake engagement duration, temporarily releasing it to allow the robot to escape clamping while maintaining overall safety through conditional re-engagement.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If holding brakes are engaged to secure holding position and save energy, then energy efficiency is improved, but the robot cannot actively move or evade clamping forces

Engineering Contradiction:
Improveenergy savingVSAvoidability to actively move
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The holding brake system transitions from a static engaged state (for energy saving) to a dynamic state where temporary reopening is permitted. This dynamic control allows the robot to maintain energy efficiency during normal operation while gaining the adaptability to actively move when clamping forces are detected through axle load monitoring.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The robot system monitors its own axle load and automatically determines when temporary brake release is needed. The control device uses the robot's own operational data (axle load, time since engagement) to self-regulate the holding brake engagement, enabling the robot to service its own safety and mobility needs without external intervention.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If holding brakes are engaged to stop robot movement upon collision detection, then collision safety is improved, but the robot remains trapped in the obstacle

Engineering Contradiction:
Improvecollision impactVSAvoidentanglement risk
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The control device performs preliminary action by temporarily reopening the holding brake after initial engagement. This preliminary release action occurs before the robot can become permanently trapped, allowing it to escape the obstacle while the brake remains engaged enough to prevent uncontrolled movement, thus reducing entanglement risk.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from axle load sensors to monitor whether the robot is clamped by an obstacle. This feedback loop allows the control device to detect clamping conditions and trigger temporary holding brake reopening, creating a closed-loop safety system that responds to actual robot-state conditions rather than operating open-loop.

Inventive Principle:
Principle #23Feedback

4Reliability

If holding brakes are engaged for extended periods to maintain safety, then safety is improved, but operational efficiency and productivity decrease

Engineering Contradiction:
ImprovesafetyVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The holding brake engagement follows a periodic pattern: initial engagement upon collision detection, followed by temporary reopening after a predetermined time period, and potential re-engagement based on axle load conditions. This periodic action allows the robot to maintain safety while periodically checking for and releasing clamping forces, improving operational efficiency without compromising overall safety.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2881225B1Method and control element for controlling a robot
Publication Date: 2022.05.04 KUKA DEUT GMBH
  • EP2881225B1 patent drawingFigure 1A~2

AI summary

According to a method according to the invention for controlling a robot (1.1 - 1.3) with an axis arrangement having at least one axis (q1, q2) with a drive and a holding brake which is closed, in particular due to monitoring (S5, S80), this holding brake is reopened depending (S20, S30, S50, S60) on an axis load and/or for (S40, S45, S70, S75) a predetermined duration (tH,i, t'H,i) or remains open before closing depending (S20, S30, S50, S60) on an axis load and/or for (S40, S45, S70, S75) a predetermined duration (tH,i, t'H,i) (S35).