Robot Programming via Workpiece Geometric Model Reference

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Solution Overview

Problem

Current programming methods for industrial robots lose reference to the workpiece, leading to inefficiencies and reduced flexibility when the workpiece is rotated or repositioned, as they rely on stored poses and paths without workpiece-specific orientation or distance maintenance, particularly in complex surface geometries.

Innovation Solution

A programming method that maintains workpiece reference by using a model with geometric parameters to derive kinematic data, such as surface normals and tangents, for precise path planning and tool orientation, ensuring consistent tool positioning and orientation relative to the workpiece surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If poses are manually taught or CAD-generated without workpiece reference, then programming is simplified and initial setup is faster, but the robot cannot adapt when the workpiece is rotated or repositioned, requiring time-consuming re-teaching

Engineering Contradiction:
Improveprogramming speedVSAvoidworkpiece repositioning adaptability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary actions by teaching the robot to recognize and adapt to the workpiece geometry before actual production. The workpiece model is created and stored in advance, containing all geometric information needed for automatic path generation. This preliminary modeling eliminates the need for re-teaching when workpieces are repositioned, as the robot can automatically recalculate paths based on the pre-stored geometric model.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the fundamental parameter reference system from fixed Cartesian poses to workpiece-relative geometric parameters. Instead of storing absolute positions and orientations, the system stores poses relative to the workpiece model geometry (surfaces, edges, vertices). When the workpiece is repositioned, the robot recalculates paths by referencing the workpiece model rather than fixed coordinates, automatically adapting to new positions and orientations.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If discrete operating points are specified without workpiece reference, then positioning is simpler, but the path between points cannot maintain consistent tool orientation and distance to the workpiece surface

Engineering Contradiction:
Improvepath specification simplicityVSAvoidtool orientation and distance consistency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The workpiece model serves as an intermediary between the discrete operating points and the actual robot path execution. Instead of directly connecting points with simple linear or arc paths, the system uses the workpiece model geometry (surfaces, edges) as intermediaries to generate paths that maintain proper tool orientation and distance. The model provides continuous geometric reference information that guides the tool along the workpiece surface, ensuring consistent orientation and spacing throughout the path.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If re-teaching is performed when workpiece position changes, then accuracy is maintained, but production time increases and automation flexibility is reduced

Engineering Contradiction:
Improvepose accuracyVSAvoidre-teaching time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system creates a digital copy of the workpiece geometry (workpiece model) that serves as a permanent reference. Instead of re-teaching physical poses when the workpiece is repositioned, the robot references the digital model copy and automatically recalculates paths based on the new workpiece position. This copying approach eliminates repetitive re-teaching while maintaining precision, as the model contains all geometric information needed for accurate path generation.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2420360B1Method and programming means for programming a robot
Publication Date: 2016.12.07 KUKA DEUT GMBH
  • EP2420360B1 patent drawingFigure 1~2
  • EP2420360B1 patent drawingFigure 3~4
  • EP2420360B1 patent drawing

AI summary

The programming unit (2) has a parameter processing unit (1) for deriving kinetic model data e.g. bi-normal vector (Bz), normal vector (Nz), tangent vector (Tz) and intermediate points (Wz), from geometric parameters of a model of an interaction object of a robot based on program instructions (5) of the robot. The model comprises a CAD model (3) of a work piece and/or a robot environment, and the model data comprises positions and/or orientations of points, lines, surfaces and spaces. A path determining unit (4) determines a path of the robot based on the model. Independent claims are also included for the following: (1) a method for programming a robot (2) a computer program product comprising program codes stored in a machine readable carrier for executing a method for programming a robot.