Articulated Chain Movement Estimation Using Temporal Evolution Models
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Solution Overview
Problem
Current systems for estimating the movement of articulated chains, such as those representing human limbs, are costly and have limited precision due to the need for multiple inertial sensors and complex algorithms, especially when trying to determine both position and orientation of all segments during activities like walking or running.
Innovation Solution
A system using a minimized number of sensors, including magnetometers and gyroscopes, that calculates the orientation of each segment by temporal evolution models linking the orientations of all segments to that of a single segment, allowing for precise estimation with reduced instrumentation and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inertial sensors are placed on each segment of the articulated chain to estimate both position and orientation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a single sensor's measurements to generate virtual copies of orientation data for other segments through temporal evolution models. Instead of placing physical sensors on each segment, the system creates mathematical copies of the motion patterns that propagate through the articulated chain, significantly reducing sensor quantity while maintaining estimation precision.
Solution Approach 2:
The single inertial sensor performs multiple functions: it directly measures the orientation of one segment while simultaneously providing data that, through temporal evolution models, enables estimation of orientations for all other segments in the articulated chain. This multi-functionality eliminates the need for dedicated sensors on each segment.
2Measurement precision
If one sensor is placed on each segment of the articulated chain to estimate orientation, then measurement precision is improved, but cost and device complexity increase
Solution Approach 1:
The system creates virtual copies of orientation measurements through temporal evolution models that propagate motion patterns from one sensor location to multiple segments. This mathematical copying approach replaces expensive physical instrumentation while maintaining precision requirements.
Solution Approach 2:
The patent extracts the essential motion information from a single sensor and separates it from the need for multiple physical sensors. By taking out only the critical orientation data from one segment and using temporal evolution to infer other segments' orientations, the system eliminates unnecessary sensor hardware and reduces overall system cost.
3Measurement precision
If complex algorithms are used to estimate movement of all segments, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the approach from complex simultaneous estimation of all segments to a sequential parameter propagation method. By using temporal evolution models that update segment orientations step-by-step based on previous states and current sensor data, the system achieves precise movement estimation with computationally efficient algorithms.
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 enables accurate estimation of the movement of articulated chains with improved precision and adaptability to gear changes, reducing the number of sensors required and lowering costs while maintaining high performance.
Implementation Method 1
measuring means for measuring a value of a first parameter representative of an orientation of a first segment of a first member, said measuring means comprising a magnetometer with at least one measuring axis
Implementation Method 2
said measuring means comprise a magnetometer with at least one measuring axis and/or a gyrometer with at least one measuring axis
Data Source
Figure 1~3
Figure 5a~5c
Figure 6~7b
AI summary
The invention relates to a method for determining the values of parameters representative of a movement of an entity represented by an articulated line, using a sensor unit comprising at least one sensor for sensing a parameter representative of an orientation of a first segment of the articulated line, which comprises the following steps: receiving an orientation value measured and supplied by the orientation sensor; and estimating a value of at least one first parameter representative of a movement of the first segment by processing the supplied attitude value. The method further comprises the following step, carried out on the basis of a predetermined motion model of the articulated line, referred to as time variation model, comprising at least one time-dependent relationship between said at least one first parameter and at least one other parameter representative of a movement of another segment of the articulated line: estimating a value of said at least one other parameter by applying the time variation model to the estimated value of said at least one parameter.