Walking Assistant Device Joint Motion Phase Calculation
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Solution Overview
Problem
Existing walking assistant devices require multiple sensors, including force/torque sensors, to aid walking, which can be cumbersome and ineffective for individuals with weak muscle strength or mobility issues, particularly in an aging society where simplicity and efficiency in assistance are crucial.
Innovation Solution
A walking assistant device that measures joint motion to calculate the walking phase without using a force/torque sensor, utilizing a support frame, detecting unit, control unit, and power unit to provide assistant torque based on corrected trajectories, allowing for selective positioning on the hip, knee, or ankle, and adapting to user-specific data such as age, sex, and body weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force/torque sensors are used to measure walking phase, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the force/torque sensor from the system, replacing it with simpler joint motion sensors. The walking phase is calculated solely from joint motion data through trajectory overlapping and phase calculation algorithms, eliminating the need for complex force/torque measurement hardware while maintaining measurement capability.
Solution Approach 2:
The patent substitutes the mechanical force/torque sensing system with a motion-based calculation system. Instead of directly measuring forces at the foot, the system uses joint angle measurements and trajectory analysis to infer walking phase, replacing complex mechanical sensing with simpler angular measurement and computational methods.
2Reliability
If multiple sensors are used to aid walking, then walking assistance accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent removes unnecessary sensors from the system, keeping only joint motion sensors that are essential for calculating walking phase. This reduction in sensor quantity simplifies the device structure and makes it easier to operate while retaining sufficient accuracy for walking assistance.
Solution Approach 2:
The system uses the wearer's own joint motion data to automatically calculate walking phase and generate assistance torque, without requiring external force measurements. The device self-adjusts based on measured joint trajectories, making operation simpler and more adaptive to individual users.
3Difficulty of detecting and measuring
If force/torque sensors are deployed on the foot, then walking phase detection is improved, but device complexity and sensor requirements increase
Solution Approach 1:
The patent extracts the walking phase detection function from the foot-mounted force/torque sensor and relocates it to joint motion sensors. The detection function is achieved through computational analysis of joint trajectories rather than direct force measurement, eliminating the need for complex foot-mounted sensor systems.
Solution Approach 2:
The patent introduces joint motion as an intermediary measurement that indirectly provides walking phase information. Instead of directly measuring force at the foot, the system measures joint angles and uses trajectory overlapping algorithms to infer walking phase, using joint motion as a mediator between simple sensors and accurate phase detection.
Data Source
AI summary
A walking assistant device may calculate a walking cycle by measuring only motion of a specific joint without a force/torque sensor (F/T sensor) of a foot, and a method of controlling the walking assistant device. The method may include measuring motion of a hinge to which different support frames are connected; overlapping a reference trajectory corresponding to the measured motion and modulation trajectories that have been modulated from the reference trajectory; correcting the overlapping trajectory to correspond to the measured motion; determining assistant torque corresponding to a phase of the corrected trajectory; and providing the determined assistant torque to the support frame.