Robot Manipulator Orientation Display Using IMU Gravity Feedback

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Solution Overview

Problem

Existing robot manipulator systems face challenges in precise manual guidance due to difficulties in accurately aligning the robot limb's orientation relative to the gravity vector, especially when the system is in motion or experiencing accelerations.

Innovation Solution

Incorporating an inertial measuring unit with a position gyroscope to determine the direction of the gravity vector and transmit the current orientation of the robot limb to a visual output unit in real-time, allowing for precise feedback and alignment regardless of the system's state of motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an inertial measuring unit with gyroscope is used to determine orientation during motion, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveorientation measurement precisionVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the inertial measuring unit continuously measures the robot manipulator's orientation relative to the gravity vector, and this information is displayed in real-time to the operator. This feedback loop enables the operator to make precise adjustments to align the manipulator with the gravity vector, thereby improving measurement precision through active correction rather than passive measurement alone.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical orientation indication methods (such as physical spirit levels or mechanical gauges) with an electronic inertial measuring unit containing gyroscopes and accelerometers. This substitution eliminates the need for complex mechanical linkage systems while providing more accurate and reliable orientation data during dynamic motion, as electronic sensors can accurately measure orientation even during acceleration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If real-time orientation feedback is provided during manual guidance, then ease of operation is improved, but loss of information increases due to latency

Engineering Contradiction:

Improvemanual guidance easeVSAvoidorientation information accuracy

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The patent ensures continuous real-time display of orientation information throughout the entire manual guidance operation. The inertial measuring unit continuously tracks the robot manipulator's orientation relative to the gravity vector without interruption, providing uninterrupted feedback to the operator. This continuous action eliminates gaps in information that would otherwise occur with periodic or intermittent measurement systems, thereby minimizing information loss due to latency.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If the robot manipulator is moved during orientation alignment, then productivity is improved, but measurement precision deteriorates due to acceleration effects

Engineering Contradiction:

Improveteaching process speedVSAvoidorientation alignment precision

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent employs a dynamic measurement system using gyroscopes and accelerometers that can accurately determine orientation even during accelerated motion. Unlike static spirit levels that fail during movement, the inertial measuring unit dynamically compensates for acceleration effects by using gyroscope data to track orientation changes relative to the gravity vector. This allows the operator to move the robot manipulator freely during the teaching process while maintaining precise orientation measurement, thereby resolving the contradiction between productivity and measurement precision.

Inventive Principle:

Principle #15Dynamics

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

Enables precise and intuitive alignment of the robot limb relative to the gravity vector, improving manual guidance by providing real-time feedback and reducing latency, thus simplifying the teaching process and enhancing the accuracy of robot manipulator operations.

Implementation Method 1

the inertial measuring unit is configured to determine the direction of a gravity vector in a stationary state of the robot element, and to determine a current orientation of the robot element relative to the gravity vector at a plurality of time points by means of a gyroscope

Methodology Applied

Scientific EffectGyroscope: Gyroscope

Data Source

PatentEP3946830B1Orientation angle display during the manual guidance of a robot manipulator

Publication Date: 2023.05.03 FRANKA EMIKA GMBH

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AI summary

The invention relates to a robot system (1) comprising a robot manipulator (3) and a visual output unit (9), the robot manipulator (3) having a robot link (5) and said robot link (5) having an inertial measuring unit (7), the inertial measuring unit (7) being designed to determine the direction of a gravity vector when the robot link (5) is immobile, and to determine, over a plurality of points in time, the actual orientation of the robot link (5) in relation to the gravity vector using an attitude gyro, and to transmit, to the visual output unit (9) the current orientation of the robot link (5) in relation to the gravity vector, and the visual output unit (9) is designed to display the current orientation of the robot link (5) in relation to the gravity vector.