Knee Assistive Device With Gear Locking for Stable Low-Energy Support
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Solution Overview
Problem
Existing knee movement assistive devices suffer from instability and high energy consumption due to the need to maintain the driver in an active state to assist knee movement, leading to incorrect movements and potential user injury.
Innovation Solution
A knee movement assistive device with a mechanism that allows the driver to switch to an idle state while maintaining tension force transmission through a Bowden cable system, using gears and locking means to ensure continuous assistance without constant energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driver is maintained in the active state to continuously assist knee movement, then the assistance stability is improved, but the energy consumption increases
Solution Approach 1:
The driver operates in periodic cycles, switching between active and idle states based on the knee movement phase. The control unit activates the driver only when assistance is needed (during specific phases of squat or knee extension), and deactivates it during other phases, creating a periodic operation pattern that reduces continuous energy consumption while maintaining necessary assistance stability
Solution Approach 2:
The system uses the user's own knee movement dynamics to trigger driver activation. The control unit detects knee angle and movement velocity, automatically activating the driver when the knee enters the assistance zone during natural movement, and deactivating it when the movement exits this zone. This self-service mechanism eliminates the need for continuous driver operation while ensuring stability when assistance is required
2Use of energy by moving object
If the driver is switched to the idle state to reduce energy consumption, then the energy efficiency is improved, but the assistance becomes unstable and may cause incorrect movements
Solution Approach 1:
The control unit continuously receives feedback from sensors monitoring knee angle and movement velocity. Based on this real-time feedback, the control unit determines when to activate or deactivate the driver, ensuring that assistance is provided precisely when needed and withdrawn when not required, thereby maintaining stability while improving energy efficiency
Solution Approach 2:
The system dynamically adjusts the driver's operational state based on real-time knee movement conditions. Rather than maintaining a fixed active state, the driver transitions between active and idle states dynamically according to the knee's position and movement phase, optimizing both energy efficiency and assistance stability through adaptive control
3Object-affected harmful factors
If the driver is kept in the active state to prevent incorrect movements, then the user safety is improved, but the overall device complexity increases
Solution Approach 1:
The control unit automatically monitors knee movement parameters and autonomously decides when to activate or deactivate the driver based on pre-programmed safety criteria. This self-service approach eliminates the need for complex real-time decision-making algorithms or additional safety sensors, maintaining user safety while keeping the control system relatively simple
Solution Approach 2:
The control unit is pre-programmed with knowledge of safe and effective knee movement phases for rehabilitation. By anticipating when assistance is needed based on knee angle and velocity thresholds, the system prepares for safe operation in advance, eliminating the need for complex real-time safety calculations and reducing overall system complexity
Data Source
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AI summary
A knee movement assistive device (1), comprising: a waist garment (2) attachable to a user waist and a calf garment (3) attachable to a user calf; an actuator (4) attached to the waist garment (2) and comprising a driver (41); a transmission cable (5) connecting the actuator (4) to the calf garment (3), the actuator (4) comprises: a first gear (42) connected to the driver (41); a second gear (43) operatively engaging the first gear (42), the transmission cable (5) being connected to said second gear (43); locking means (6) operatively engaging the first (42) and the second (43) gears.