Manipulator Tilt Compensation for Accurate Robot Positioning

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Solution Overview

Problem

Existing manipulator control systems fail to effectively correct the operation of a manipulator when the base tilts relative to a reference surface, leading to operational errors such as incorrect target positioning and collisions with obstacles.

Innovation Solution

A manipulator controller that includes a control unit capable of detecting tilt angles and outputting notifications when the tilt exceeds a predetermined value, along with a correction unit that adjusts the target position and obstacle positions based on the tilt angles to ensure accurate operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the manipulator operates without tilt correction on a sloping floor, then the operation speed is maintained, but the positioning accuracy deteriorates causing operational errors

Engineering Contradiction:
Improvepositioning accuracyVSAvoidoperation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system changes the coordinate system parameters by detecting tilt angles and transforming target position coordinates from the base coordinate system to the world coordinate system, allowing accurate positioning despite base tilt while maintaining operation speed

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The tilt sensor provides real-time feedback on base inclination, enabling the control unit to dynamically adjust target position calculations and maintain positioning accuracy without interrupting the operation flow

Inventive Principle:
Principle #23Feedback

2Reliability

If the manipulator is controlled to reflect the tilt angle, then the positioning accuracy is improved, but the device complexity increases due to additional sensors and control processing

Engineering Contradiction:
Improveoperational reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tilt sensor acts as an intermediary device that provides tilt angle information to the control unit, which then uses this information to calculate corrected target positions, reducing the complexity burden on the main manipulator control system

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control system is segmented into independent functional modules: tilt detection module, coordinate transformation module, and manipulator control module, allowing each to operate independently and simplifying overall system management

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the manipulator reaches target positions without tilt compensation, then the operation simplicity is maintained, but harmful factors increase due to collisions with obstacles

Engineering Contradiction:
Improveoperation simplicityVSAvoidcollision risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary coordinate transformation of target positions based on detected tilt angles before the manipulator executes movement, pre-compensating for tilt effects and preventing collisions without complicating the execution phase

Inventive Principle:
Principle #10Preliminary action

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 proposed solution reduces operational errors by accurately correcting the target position and obstacle positions in real-time, preventing collisions and ensuring precise manipulator operations even when the base tilts.

Implementation Method 1

a tilt sensor that detects a tilt angle of the movable base with respect to a horizontal plane

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3822045B1Manipulator control device, manipulator control method, and manipulator control program
Publication Date: 2025.04.30 OMRON CORP
  • EP3822045B1 patent drawingFigure 1
  • EP3822045B1 patent drawingFigure 2
  • EP3822045B1 patent drawingFigure 3~4

AI summary

A manipulator controller (10) includes a tilt angle obtainer (30) that obtains a tilt angle of a movable unit (M) receiving a robot (RB) relative to a reference surface, a target position obtainer (32) that obtains a target position of the robot (RB) on the movable unit (M) having no tilt to the reference surface, a correction unit (36) that corrects, based on the tilt angle obtained by the tilt angle obtainer (30) and the target position obtained by the target position obtainer (32), the target position to a corrected target position in accordance with the tilt angle, and a control unit (38) that controls an operation of the robot (RB) based on the corrected target position.