Robot Programming from Human Demonstration Using Vision and Force Sensors

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Solution Overview

Problem

Conventional methods for teaching industrial robots to perform pick and place operations are unintuitive, time-consuming, and error-prone, especially for non-expert operators, and existing systems face challenges with accurate detection due to visual occlusion and difficulty in deciphering hand velocity transitions.

Innovation Solution

A method using force and vision sensors to detect the human demonstrator's hand and workpiece positions and state transitions, generating robot programming commands that simplify the teaching process by capturing motions and state change logic, and refining motions to remove extraneous hand movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a motion capture system with multiple cameras and marker dots is used to teach robot programming, then the accuracy of recording positions and orientations is improved, but the cost and setup complexity increase significantly

Engineering Contradiction:
Improveaccuracy of recording positionsVSAvoidsetup complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex motion capture system infrastructure (multiple cameras, marker dots, synchronization equipment) by replacing it with a simplified vision system using standard cameras and computer vision algorithms to detect hand and workpiece positions without requiring specialized hardware infrastructure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual model of the work cell and objects based on images captured by standard cameras, generating coordinate information through image processing rather than direct physical measurement with specialized equipment, thus copying the essential spatial relationships without the complex measurement infrastructure

Inventive Principle:
Principle #26Copying

2Device complexity

If visual tracking alone is used to detect hand and workpiece positions, then the system simplicity is improved, but the accuracy deteriorates due to visual occlusion and difficulty in deciphering hand velocity transitions

Engineering Contradiction:
Improvesystem simplicityVSAvoidaccuracy of detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges multiple detection approaches by combining vision sensor data with force sensor data, where the force sensor detects contact events and state transitions that are difficult to determine from vision alone, compensating for visual occlusion and improving overall detection accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms where force sensor information about contact forces and state transitions is continuously fed back to refine the interpretation of vision data, allowing the system to correctly identify hand velocity transitions and contact events even when visual information is ambiguous or occluded

Inventive Principle:
Principle #23Feedback

3Device complexity

If a teach pendant is used to instruct robot movements incrementally, then the robot programming can be performed with simple equipment, but the time required for programming increases significantly

Engineering Contradiction:
Improveequipment simplicityVSAvoidprogramming speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent uses vision and force sensors to automatically capture and record the human operator's natural hand movements and actions as a model, then copies this demonstrated behavior into robot program commands, eliminating the need for slow incremental teaching while maintaining equipment simplicity

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical incremental teaching process (manual movement and recording) with an automated sensing and recognition system that captures motion data through vision and force sensors, then processes this data to generate robot commands automatically, substituting manual mechanical teaching with automated sensor-based programming

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If existing systems use special gloves with sensors to determine hand actions, then the hand motion detection accuracy is improved, but the ease of operation deteriorates due to the special equipment requirement

Engineering Contradiction:
Improvehand motion detection accuracyVSAvoidease of demonstration
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent enables the human operator to perform demonstration without any special equipment or accessories, using natural hand movements that are captured by external vision and force sensors, thus maintaining ease of operation while achieving accurate hand motion detection through non-contact sensing methods

Inventive Principle:
Principle #25Self-service

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 method enables faster, more intuitive, and accurate robot programming by accurately capturing human demonstrations, reducing errors and complexity, and improving the reliability of pick and place operations.

Implementation Method 1

a vision sensor to detect position and pose of the human's hand and optionally a workpiece during teaching of an operation

Methodology Applied
Scientific EffectVision detection: Photoelectric Effect

Implementation Method 2

The force sensor, located either beneath the workpiece or on a tool, is used to detect force information

Methodology Applied
Scientific EffectForce detection: Piezoelectric Effect

Data Source

PatentUS20230120598A1Robot program generation method from human demonstration
Publication Date: 2023.04.20 FANUC LTD
  • US20230120598A1 patent drawing
  • US20230120598A1 patent drawing
  • US20230120598A1 patent drawing

AI summary

A method for teaching a robot to perform an operation based on human demonstration using force and vision sensors. The method includes a vision sensor to detect position and pose of both the human's hand and optionally a workpiece during teaching of an operation such as pick, move and place. The force sensor, located either beneath the workpiece or on a tool, is used to detect force information. Data from the vision and force sensors, along with other optional inputs, are used to teach both motions and state change logic for the operation being taught. Several techniques are disclosed for determining state change logic, such as the transition from approaching to grasping. Techniques for improving motion programming to remove extraneous motions by the hand are also disclosed. Robot programming commands are then generated from the hand position and orientation data, along with the state transitions.