Motion Capture Closed-Loop Control for High-Precision Tracking

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Solution Overview

Problem

Existing control systems for controllable devices, such as vehicles and manufacturing robots, face challenges with accuracy, update frequency, and cost due to the use of on-board sensors, which can add weight and increase costs without providing the necessary precision and frequency for certain applications.

Innovation Solution

A closed-loop feedback control system utilizing a motion capture system that measures the motion characteristics of controllable devices with high accuracy and frequency, allowing for real-time adjustments through a processor and motion control system, eliminating the need for on-board sensors by using passive retro-reflective markers and remote motion capture devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If on-board sensors are used for control systems, then control functionality is achieved, but weight and cost increase while accuracy and update frequency remain insufficient

Engineering Contradiction:
Improvecontrol accuracyVSAvoidvehicle weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The measurement function is extracted from the vehicle itself and placed in an external motion capture system. Passive retro-reflective markers are attached to the vehicle, and the actual measurement is performed by external cameras tracking these markers, thereby eliminating the need for heavy on-board sensors while achieving high measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Passive retro-reflective markers serve as intermediaries between the vehicle and the external motion capture system. These markers reflect light from external sources back to the cameras, enabling accurate tracking without requiring active sensors or power sources on the vehicle itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If on-board sensors are used for control systems, then control functionality is achieved, but cost increases while accuracy and update frequency remain insufficient

Engineering Contradiction:
Improvecontrol accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The expensive and complex on-board sensor suite is extracted and replaced with simple passive markers on the vehicle and a shared external motion capture system that can serve multiple vehicles, significantly reducing per-vehicle cost and complexity while maintaining or improving measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The external motion capture system serves as a universal measurement platform that can track multiple controllable devices simultaneously. This multi-functional system replaces individual on-board sensors on each device, reducing overall system cost and complexity while providing high-precision tracking for all devices.

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

3Productivity

If on-board sensors are used for control systems, then control functionality is achieved, but update frequency is insufficient for high-precision applications

Engineering Contradiction:
Improveupdate frequencyVSAvoidvehicle weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The measurement function is extracted to an external motion capture system that is not constrained by vehicle weight or power limitations. This external system can use powerful cameras and lighting with high frame rates to achieve update frequencies sufficient for high-precision control applications without adding weight to the vehicle.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach provides highly accurate, rapid, and cost-effective control of controllable devices, enabling precise positioning and stabilization with reduced weight and complexity, while allowing for scalable and adaptable control systems.

Implementation Method 1

passive retro-reflective markers and remote motion capture devices

Methodology Applied
Scientific EffectRetro-reflection: Retroreflector

Data Source

PatentEP2682837B1Closed-loop feedback control using motion capture system
Publication Date: 2019.10.16 THE BOEING CO
  • EP2682837B1 patent drawingFigure 1
  • EP2682837B1 patent drawingFigure 2
  • EP2682837B1 patent drawingFigure 3

AI summary

Systems and methods for closed-loop feedback control of controllable devices using motion capture systems are disclosed. In one embodiment, a system includes a motion capture system configured to measure one or more motion characteristics of one or more controllable devices as the one or more controllable devices are operating within a control volume. A processor receives the measured motion characteristics from the motion capture system and determines a control signal based on the measured motion characteristics. A position control system receives the control signal and continuously adjusts at least one motion characteristic of the one or more controllable devices in order to maintain or achieve a desired motion state. The controllable device may be equipped with passive retro-reflective markers. The motion capture system, the processor, and the position control system comprise a complete closed-loop feedback control system.