Joint Bending State Determining Device Using Gravity Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Patients with joint pain face difficulties in determining the correct bending state of their joints during rehabilitation exercises, especially when performing these exercises without supervision at home.
Innovation Solution
A joint bending state determining device comprising two gravity sensors and a processor that calculates the joint angle by obtaining polar and azimuth angles, and distances between the sensors and the joint, allowing for flexible placement and reduced need for specific assistive devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to determine joint bending state, then measurement precision is improved, but device complexity and weight increase
Solution Approach 1:
The system segments the measurement function by using two separate gravity sensors positioned at different locations (e.g., upper leg and lower leg) to collectively determine the joint bending state. Each sensor independently measures local gravitational acceleration, and the processor combines these segmented measurements to calculate the overall joint angle, achieving comprehensive measurement while maintaining individual sensor simplicity
Solution Approach 2:
The patent replaces complex mechanical joint angle measurement systems with a gravity-based sensing system. Instead of using mechanical encoders or goniometers directly at the joint, the system uses gravity sensors that measure gravitational acceleration vectors, and through computational processing, derives the joint bending state from these gravity measurements, thereby simplifying the physical measurement mechanism
2Measurement precision
If multiple sensors are used to determine joint bending state, then measurement precision is improved, but device weight increases
Solution Approach 1:
The system extracts only the essential measurement function (gravity sensing) and implements it with minimal components. By using standard gravity sensors that measure gravitational acceleration in three axes, the system obtains sufficient information to calculate joint angles without adding unnecessary weight from more complex sensor arrays or redundant measurement devices
Solution Approach 2:
The patent replaces heavy mechanical measurement devices with lightweight gravity sensors and computational processing. The gravity sensors are significantly lighter than traditional mechanical joint angle sensors, and the addition of a processor enables complex measurements to be made with minimal additional hardware weight, thereby improving measurement precision while minimizing weight increase
3Measurement precision
If fixed sensor placement is required, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The system implements dynamic adaptability by allowing sensor placement at multiple possible locations (e.g., upper leg or lower leg for knee joint measurement) while maintaining measurement accuracy. The processor dynamically adjusts the calculation method based on the actual sensor positions and distances from the joint, enabling the system to adapt to different user configurations without compromising measurement precision
Solution Approach 2:
The patent incorporates adjustable parameters including sensor-to-joint distance (first distance and second distance) that can be modified based on actual placement. By making these parameters variable rather than fixed, the system accommodates different user body types and placement preferences while maintaining accurate joint angle calculation through real-time parameter adjustment in the processing algorithm
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
Enables accurate determination of joint bending states with reduced complexity and weight, allowing for flexible placement of sensors and improved user freedom, while also improving the tracking of rehabilitation progress.
Implementation Method 1
a sensor group (11) and a processor (13). The sensor group (11) comprises a first gravity sensor (11a) and a second gravity sensor (11b)
Data Source
AI summary
A joint bending state determining device comprises a sensor group and a processor. The sensor group comprises first and second gravity sensors. The first/second gravity sensor generates a first/second polar angle and a first/second azimuth angle. The processor obtains a first length corresponding to the first gravity sensor and a second length corresponding to the second gravity sensor, obtains a set of coordinates of a joint in a coordinate system according to the first polar angle, the first azimuth angle and the first length, obtains a set of coordinates of the second gravity sensor in the coordinate system according to the set of coordinates of the joint, the second polar angle, the second azimuth angle and the second length, and obtains a joint angle according to the set of coordinates of the second gravity sensor in the coordinate system, the first length and the second length.