Robot Arm End Vibration Control Using Inertia Actuators

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Solution Overview

Problem

Current robot arm machining technologies face challenges in reducing vibrations during heavy-duty applications, leading to inefficiencies and surface roughness, as existing dampers are ineffective for systems with varying structural resonant frequencies.

Innovation Solution

A method involving the mounting of inertia actuators and vibration signal capturing units at the processing end of the robot arm to detect vibrations, calculate output forces using a central processing unit, and apply counteracting forces to reduce vibrations, allowing for dynamic rigidity enhancement and increased machining depth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive tuned mass dampers are used to reduce vibration at specific frequency, then vibration reduction is achieved at that frequency, but the performance is remarkably reduced when structural resonant frequency varies

Engineering Contradiction:

Improvevibration reduction effectivenessVSAvoidadaptability to varying resonant frequency

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs active inertia actuators that can dynamically adjust their output force in real-time based on feedback from vibration sensors. Unlike passive tuned mass dampers with fixed parameters, this active system continuously adapts to varying resonant frequencies by modifying the counteracting force magnitude and phase, ensuring effective vibration reduction across different operating conditions and robot arm configurations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates vibration sensors that continuously monitor the robot arm's vibration state and feed this information back to the control unit. The control unit processes this feedback signal and adjusts the inertia actuators' output accordingly, creating a closed-loop control system that automatically adapts to changing resonant frequencies and maintains optimal vibration reduction performance.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If robot arm is used for flexible applications and multi-axis machining, then flexibility and application range are improved, but rigidity is reduced leading to vibration problems

Engineering Contradiction:

Improveflexibility for multi-axis machiningVSAvoidrigidity

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent uses inertia actuators to generate counteracting forces that oppose the vibration forces acting on the robot arm during machining operations. These actuators function as dynamic counterweights, producing forces equal in magnitude but opposite in direction to the vibrational forces, thereby compensating for the inherent flexibility of the robot arm and maintaining machining stability.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The system dynamically changes the parameters of the counteracting force (magnitude, phase, and frequency) based on real-time vibration measurements. By continuously adjusting these parameters, the system adapts to different machining conditions, tool positions, and robot arm configurations, effectively compensating for rigidity limitations across various operating scenarios.

Inventive Principle:

Principle #35Parameter changes

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 approach effectively reduces vibrations at the processing end of the robot arm, enhancing machining efficiency and tool service life by continuously monitoring and counteracting vibrations, thereby improving machining stability and depth.

Implementation Method 1

applying the at least one vibration signal capturing unit to detect a vibration generated at the processing end of the robot arm so as to generate a vibration signal

Methodology Applied

Scientific EffectVibration detection: Vibration

Implementation Method 2

having the inertia actuator to apply the output force to the processing end of the robot arm for counteracting the vibration at the processing end of the robot arm

Methodology Applied

Scientific EffectInertia: Inertia

Data Source

PatentUS11577389B2Method for reducing vibration of robot arm

Publication Date: 2023.02.14 IND TECH RES INST

AI summary

A method for reducing vibration of a robot arm includes: a step of mounting at least one inertia actuator and at least one vibration signal capturing unit to a processing end of a robot arm; a step of applying the at least one vibration signal capturing unit to detect a vibration generated at the processing end of the robot arm so as to generate a vibration signal; a step of applying a central processing unit to evaluate the vibration signal and coordinates of the processing end of the robot arm so as to capture at least one set of corresponding control parameters for calculating at least one output force; and, a step of having the inertia actuator to apply the output force to the processing end of the robot arm for counteracting the vibration at the processing end of the robot arm.