Robot Motor Dynamic Braking for Posture Stability During Maintenance

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Solution Overview

Problem

Conventional robot systems face instability issues when the main power supply is disconnected, leading to sudden changes in robot posture, which can be dangerous, and require labor-intensive measures like suspension by cranes to prevent falls.

Innovation Solution

A robot system equipped with a short-circuiting device that applies a dynamic brake to motors via a short circuit and an auxiliary power supply, allowing for controlled stabilization of the robot's posture by short-circuiting electrodes, thereby preventing sudden changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the main power supply is disconnected and only maintenance power supply is connected, then the brake is released and the robot posture can be changed for maintenance work, but the robot posture suddenly changes (e.g., robotic arm suddenly falls due to its own weight) causing danger

Engineering Contradiction:
Improvemaintenance operationVSAvoidposture stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The short-circuiting device is activated before maintenance work begins to apply dynamic braking to the motors, creating a counteracting force that prevents the robotic arm from falling due to gravity. This preliminary protective action ensures that when the brake is released for maintenance, the motor's dynamic braking compensates for the lost mechanical braking force, maintaining posture stability throughout the maintenance operation.

Inventive Principle:
Principle #9Preliminary anti-action

2Ease of operation

If the brake is released to enable posture change for maintenance, then maintenance work can be performed, but labor and time consuming measures (suspension by crane) are required to prevent sudden fall

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidpreventive measure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention replaces the complex mechanical preventive measure (crane suspension system) with an electrical control solution. The short-circuiting device electrically connects the motor terminals to create dynamic braking, substituting the need for external mechanical support structures. This electrical substitution simplifies the overall system while achieving the same safety objective of preventing sudden robotic arm falls during maintenance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a crane is used to suspend the robotic arm to prevent sudden fall, then safety is improved, but the process becomes labor and time consuming

Engineering Contradiction:
ImprovesafetyVSAvoidsetup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The motor itself provides the braking function through its inherent electromagnetic properties when the terminals are short-circuited. The motor's back-EMF generates a counter-torque that automatically resists gravitational force on the robotic arm, eliminating the need for external crane systems. This self-service approach uses the motor's own characteristics to provide safety, significantly reducing setup time and labor requirements compared to external mechanical support systems.

Inventive Principle:
Principle #25Self-service

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

The solution effectively stabilizes the robot's posture, enabling safe maintenance and operation by applying a dynamic brake through the short-circuiting device, which can be activated at desired times, and provides greater output power compared to single-phase motors.

Implementation Method 1

a short circuit that is electrically connected to the robot and provided separately from a robot controller configured to control the robot, the short circuit being configured to apply a dynamic brake to each motor

Methodology Applied
Scientific EffectDynamic braking: Electromagnetic Induction

Implementation Method 2

at least one non-excitation actuated electromagnetic brake that is provided for the respective at least one motor

Methodology Applied
Scientific EffectElectromagnetic brake: Electromagnet

Data Source

PatentEP3769919B1Short-circuiting device and robot system provided with same
Publication Date: 2024.09.11 KAWASAKI JUKOGYO KK
  • EP3769919B1 patent drawingFigure 1~2
  • EP3769919B1 patent drawingFigure 3
  • EP3769919B1 patent drawingFigure 4~5

AI summary

A short-circuiting device according to the present invention includes a short circuit that is electrically connected to a robot, the robot including a robotic arm and at least one motor, the robotic arm including at least one joint shaft that is provided with the respective at least one motor, the short circuit being provided separately from a robot controller configured to control the robot, the short circuit being configured to apply a dynamic brake to each motor.