Robotic Arm Shape Control for Accurate Tip Following

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Solution Overview

Problem

Existing robotic arm control methods, such as leader-follower algorithms, limit the motion capability of proximal segments and require predefined paths, making it difficult to accurately follow complex paths and adapt to new positions, especially in redundant mechanisms and dynamic environments.

Innovation Solution

A method that calculates a new shape for the robotic arm using the current shape and desired tip position, allowing for flexible path following without requiring a predefined path, by interpolating segment positions and orientations to maintain smooth motion and adapt to changing environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If basic leader-follower algorithm is used to control robotic arm segments, then the control method is simple and easy to implement, but the motion capability of proximal segments is lost and path following precision deteriorates

Engineering Contradiction:
Improvecontrol method simplicityVSAvoidpath following precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The control method transitions from static copying of segment shapes to dynamic calculation of new shapes based on current arm configuration and desired tip position. The control algorithm continuously adapts the arm shape by calculating optimal segment positions rather than rigidly copying previous configurations, enabling both simplicity and precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameters from simple shape copying to calculated shape transformation. By using the current arm shape and desired tip position as input parameters, the system calculates new segment positions that optimize both motion capability and path following accuracy, resolving the contradiction between control simplicity and precision.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If leader-follower algorithm copies segment shapes, then control implementation is straightforward, but the robot cannot adapt to new positions and configurations

Engineering Contradiction:
Improvecontrol implementation easeVSAvoidconfiguration adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The control system becomes dynamic by continuously calculating new arm shapes based on current configuration and desired tip position rather than statically copying segment shapes. This enables the robot to adapt to various positions and configurations while maintaining straightforward control implementation through a unified calculation approach.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The calculated shape method provides universal applicability across different robot configurations and task requirements. The same control algorithm can handle various arm positions, orientations, and desired tip poses, making the system versatile while keeping control implementation simple through a general-purpose calculation framework.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If rigid members and rigid joints are used in robotic arm, then structural stability is maintained, but path following accuracy deteriorates in complex spaces

Engineering Contradiction:
Improvestructural stabilityVSAvoidpath following accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The control method introduces dynamic shape calculation that allows the arm to optimally position rigid segments for accurate path following. By calculating the ideal configuration of rigid members based on desired tip position and current state, the system maintains structural stability while achieving high path following accuracy in complex spaces.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If multiple articulated links per segment are used, then the arm can adopt curved shapes for better path following, but control complexity increases

Engineering Contradiction:
Improvepath following capabilityVSAvoidcontrol complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control algorithm merges the control of multiple articulated links within each segment into a unified shape calculation process. Instead of independently controlling each link, the system calculates the optimal configuration of all links together to achieve the desired arm shape, reducing control complexity while maintaining the ability to follow complex paths.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2304509B1Method of controlling a robotic arm
Publication Date: 2021.02.24 OLIVER CRISPIN ROBOTICS
  • EP2304509B1 patent drawingFigure 1~4
  • EP2304509B1 patent drawingFigure 5~7
  • EP2304509B1 patent drawingFigure 8~10

AI summary

The invention relates to a method of controlling the position of an elongate robotic arm comprising articulated segments. An actuator is associated with each segment to control its position, and a control system operates the actuators. Data representing the position of the arm is gathered and compared to input data that represents a required new position of a part of the arm. Data representing the required new position of the arm is then calculated, attempting to keep the remainder of the arm as close as possible to its previous position. The actuators are operated to move the arm into the new position. In tip following, the data representing the new position may define a path, and the arm may be fitted to the path by matching the position and orientation of a point on each pair of adjacent segments to that of the path.