Prosthetic Foot Resistance Control for Safe Gait Transitions
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Solution Overview
Problem
Existing prosthetic feet lack reliable and safe control of resistance behavior during situational transitions, particularly at the beginning of walking after a phase of standing, which can compromise user safety.
Innovation Solution
A method for controlling a prosthetic foot that determines ground contact and spatial position using sensors and an inertial measuring unit, adjusting resistance to pivoting based on these factors to ensure safe and adaptive control during stance and swing phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistance is adjusted based solely on sensor data without considering spatial position and ground contact, then control simplicity is maintained, but safety and reliability deteriorate during situational transitions
Solution Approach 1:
The patent combines multiple sensing modalities (ground contact detection, spatial position tracking via IMU, and angle sensing) into a unified control system. The control unit integrates data from these different sources to make resistance adjustment decisions, merging previously separate control functions into a coordinated system that enhances reliability during transitions between standing and walking phases.
Solution Approach 2:
The control system continuously monitors multiple parameters including ground contact status, spatial position, and foot angle, using this feedback to dynamically adjust resistance. The IMU provides continuous spatial orientation feedback, while ground contact sensors provide binary feedback about stance phase, allowing the system to adapt resistance in real-time based on the user's actual state rather than relying on predetermined sequences.
2Reliability
If dorsal movement is always permitted for natural gait, then ease of movement is improved, but safety deteriorates due to unwanted dorsiflexion during standing
Solution Approach 1:
The resistance device dynamically adjusts its characteristics based on the detected phase of gait. During standing phase, the system permits dorsal movement within safe limits, while during swing phase transitions, it enables greater dorsiflexion freedom. The control system continuously modifies resistance based on real-time detection of ground contact and spatial position, creating a dynamic control strategy that adapts to the user's movement state.
Solution Approach 2:
The system changes the resistance parameter dynamically based on detected gait phase and spatial position. By monitoring the angle between the foot part and upper part along with spatial orientation from the IMU, the control unit adjusts resistance levels to permit or prevent dorsiflexion at appropriate times, transforming a static resistance device into one with variable characteristics that respond to operational conditions.
3Productivity
If resistance adjustment is delayed during gait transitions, then system response simplicity is maintained, but productivity deteriorates due to slower adaptation to movement changes
Solution Approach 1:
The control system performs preliminary detection and evaluation of gait phase transitions by continuously monitoring spatial position and ground contact status before actual movement occurs. The IMU detects changes in orientation that precede full gait transitions, allowing the control unit to prepare resistance adjustments in advance, smoothing the transition and improving adaptation speed without requiring complex reactive control.
Data Source
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AI summary
The invention relates to a method for controlling a prosthetic foot (10) which has an upper part (11) with a fastening element (13) for a proximal prosthetic component (20) and a foot part (12) mounted thereon so as to be pivotable about a pivot axis (15), comprising a resistance device (40) used to counteract a pivoting movement of the foot part (12) relative to the upper part (11) by way of an adjustable resistance (Am), and comprising a control device (70) which is coupled to the resistance device (40) and to at least one sensor (60) and by means of which the resistance to pivoting is set on the basis of sensor data, wherein ground contact of the foot part (12) with the ground is determined by way of at least one sensor (60), wherein the relative spatial position of the foot part (12) and/or of the upper part (11) is determined using an inertial measurement unit (30) and wherein the resistance (Am) to pivoting is altered on the basis of the presence or lack of ground contact and the determined relative spatial position and/or the determined route of the relative spatial position.