Knee-Joint Walking Robot Joint Angle Control via Foot Sole Pressure
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Solution Overview
Problem
Existing systems fail to accurately estimate the joint angle of a knee-joint type walking training robot, making it difficult to control the robot according to the walking dynamics of users, particularly for rehabilitation purposes.
Innovation Solution
A system utilizing pressure sensors to measure foot sole pressure, estimating the movement time and contact length with the ground, and calculating the joint angle based on these measurements to control the robot's joint angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing systems are used to control joint angle, then the system structure is simple, but the joint angle estimation accuracy is insufficient
Solution Approach 1:
The system divides the foot sole into multiple pressure sensing zones (heel, midfoot, forefoot, toe) with separate pressure sensors in each zone. This segmentation allows independent measurement of pressure distribution across different foot regions, enabling accurate estimation of gait phase and joint angle through analysis of pressure patterns in each segment rather than requiring a single complex sensor system.
Solution Approach 2:
The patent introduces pressure sensors as intermediary devices that indirectly measure joint angle by detecting foot sole pressure distribution. Instead of directly measuring knee joint angle, the system uses pressure sensors on the foot sole as intermediaries to infer gait phase and calculate joint angle through mathematical relationships, simplifying the overall measurement system while maintaining accuracy.
2Measurement precision
If pressure sensors are used to measure foot sole pressure, then the gait phase can be accurately estimated, but the device complexity increases
Solution Approach 1:
The pressure sensor system is designed to perform multiple functions: detecting gait phase, estimating joint angle, monitoring walking speed, and analyzing gait patterns. By making the pressure sensing system multi-functional, the patent avoids adding separate dedicated sensors for each measurement, thereby improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system uses the natural pressure distribution that occurs during walking as the measurement source, rather than requiring external actuation or complex sensor arrays. The foot sole pressure pattern that naturally occurs during gait serves the dual purpose of being both the movement being analyzed and the measurement signal, eliminating the need for additional active sensing mechanisms.
3Reliability
If the system actively responds to gait phase estimation, then the rehabilitation effectiveness is improved, but the control system complexity increases
Solution Approach 1:
The system implements closed-loop feedback by continuously monitoring pressure sensor data, estimating gait phase in real-time, and adjusting robot joint angle accordingly. The estimated gait phase feeds back to the control unit, which modifies the robot's assistance torque and joint angle to match the user's natural gait cycle, improving rehabilitation effectiveness through adaptive response while using straightforward control logic.
Solution Approach 2:
The control system dynamically adjusts the robot's joint angle and assistance torque based on the detected gait phase. During different phases of the gait cycle (stance phase, swing phase), the system automatically modifies its support characteristics to provide appropriate assistance, transforming from a static fixed-position device to a dynamic adaptive system that responds to user needs without requiring complex manual intervention.
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 precise estimation and control of the joint angle, improving the effectiveness of walking rehabilitation by correlating gait phase with knee-joint movement, facilitating better walking training for users.
Implementation Method 1
a pressure sensor that measures a pressure of a foot sole of a walker
Data Source
AI summary
The present invention relates to a system and a method for controlling a joint angle of a knee-joint type walking training robot which estimates a walking stage of a person receiving rehabilitation for walking and actively responds to the walking stage on the basis thereof. The present invention can easily control the joint angle of the knee-joint type walking training robot by providing a configuration comprising: a pressure measuring device for measuring the pressure on the sole of a walker's foot by using a pressure sensor; and a joint angle estimating device for estimating the joint angle of a knee-joint by extracting movement time of the walk and the length of the part of the sole contacting the ground on the basis of the sole's pressure measured by the pressure measuring device.