Articulated Structure Geometric Parameter Identification

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Solution Overview

Problem

Existing methods for identifying geometric parameters of articulated structures, such as those in robotics and biomechanics, rely on direct measurements which are often cumbersome or inaccurate, lacking a comprehensive approach to simultaneously determine segment lengths and reference frame positions and orientations.

Innovation Solution

A system of distributed sensors, including accelerometers, is secured to the articulated structure to extract geometric and kinetic parameters by determining sensor assembly positions and orientations through a series of calculations and predictive modeling, minimizing errors and providing explicit, optimal estimates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct measurement methods (tape measure or optical system) are used to measure segment lengths and reference frame positions, then measurement accuracy may be improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces direct mechanical measurement methods (tape measures, optical systems) with an inertial measurement system using accelerometers and gyroscopes. The geometric parameters are derived through integration and calculation of motion data rather than direct physical measurement, eliminating the need for complex external measurement equipment while maintaining accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The measurement system uses the articulated structure's own motion and the sensors attached to it to determine geometric parameters. The system is self-contained, requiring no external measurement equipment or operators, and automatically computes segment lengths and reference frame positions from the motion data collected by its own sensors.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If direct measurement methods are used to locate reference frames on segments, then measurement precision may be improved, but ease of operation deteriorates

Engineering Contradiction:

Improvereference frame position accuracyVSAvoidease of operation

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual or optical measurement procedures for locating reference frames with an automated computational approach. The reference frame positions are calculated from the relative positions and orientations of sensors attached to known locations on the segments, eliminating the need for direct measurement operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent establishes reference frames and sensor positions during an initial calibration phase using the structure's motion data. Once established, these reference frames can be used for subsequent measurements without requiring repeated direct measurement operations, significantly improving ease of operation for ongoing use.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If a comprehensive system measures both geometric parameters and reference frame positions simultaneously, then productivity is improved, but device complexity deteriorates

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a universal measurement system that simultaneously performs multiple functions: measuring segment lengths, determining reference frame positions and orientations, and capturing motion data. The same inertial sensors and computational algorithms used for one purpose can determine all geometric parameters, eliminating the need for separate measurement systems for each parameter type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the measurement of geometric parameters and reference frame positions into a single integrated process. Both types of information are derived from the same set of inertial sensor measurements through unified computational algorithms, achieving comprehensive measurement capability while avoiding the complexity of multiple separate measurement systems.

Inventive Principle:

Principle #5Merging (Combining)

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 method allows for accurate, automatic, and practical identification of critical geometric parameters and reference frames, particularly expressing the estimation as a linear least squares problem, ensuring explicit and optimal calculations.

Implementation Method 1

Said measurements system comprises at least one accelerometer

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Data Source

PatentUS10386179B2Method of identifying geometric parameters of an articulated structure and of a set of reference frames of interest disposed on said structure

Publication Date: 2019.08.20 MOVEA

AI summary

Parameters characterizing the orientation and the position of each sensor, including at least one accelerometer, are evaluated in the reference frame of each segment, together with the length of each segment, by using predetermined configurations and motions of a structure to which the sensors are attached. This makes it possible to provide a device for capturing the motions of a body with measurements which enables greater reliability of the measurements.