Exoskeleton Knee Joint Locking Mechanism Without Knee Motor
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Solution Overview
Problem
Existing knee joint mechanisms in rehabilitation walking aids are costly, heavy, consume high energy, and require continuous power supply, leading to increased weight, size, and cost, with potential for secondary injuries due to inadequate weight-bearing support.
Innovation Solution
A knee joint mechanism powered by the hip of an exoskeleton robot, utilizing angle sensors to control a drive assembly for unlocking and locking, eliminating the need for a power source at the knee joint, and incorporating a locking mechanism with a worm gear assembly for ergonomic support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motor and harmonic reducer are used to drive the knee joint, then the knee joint can be controlled, but the weight and size of the exoskeleton increase
Solution Approach 1:
The patent extracts the motor from the knee joint location and relocates it to the hip joint. The knee joint is driven passively through gravitational force and mechanical linkage when the hip joint moves, eliminating the need for a separate knee motor while maintaining control functionality.
Solution Approach 2:
The hip joint motor serves multiple functions: it drives both the hip joint movement and indirectly controls the knee joint through the mechanical linkage system. This multi-functionality reduces the total number of motors required in the system.
2Ease of operation
If two knee joint driving mechanisms are installed (one on each side), then bilateral knee control is achieved, but the cost and weight increase
Solution Approach 1:
The hip joint driving mechanism provides universal control for both left and right knee joints through symmetrical mechanical linkage design. A single motor system at the hip can control bilateral knee movement, reducing component count and manufacturing cost.
3Use of energy by moving object
If high-capacity batteries are used to power the knee joint mechanisms, then continuous power supply is ensured, but the weight and cost increase
Solution Approach 1:
The patent removes the knee joint motor and its associated power consumption requirements. By using passive gravitational driving for the knee joint, the system reduces overall power demand, allowing for smaller battery capacity while maintaining continuous operation.
Solution Approach 2:
The knee joint activation occurs periodically during the walking cycle, synchronized with hip joint movement. The knee joint is driven only when needed during specific phases of gait, reducing continuous power requirements compared to constantly powered systems.
4Weight of moving object
If a torsion spring is used to store and release energy, then the device is compact and light, but the weight-bearing support effect is poor
Solution Approach 1:
The locking mechanism is pre-positioned and ready to engage before weight-bearing occurs. When the knee joint reaches the appropriate angle during gait, the locking mechanism automatically engages to provide immediate weight-bearing support, ensuring strength is available when needed.
Solution Approach 2:
The system transitions from a purely elastic torsion spring design to a dynamic system that combines elastic energy storage with mechanical locking. The locking mechanism provides rigid support during weight-bearing phases while maintaining the lightweight advantage of spring-based energy storage during non-weight-bearing phases.
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
The mechanism achieves efficient weight-bearing support, reduces energy consumption, and prolongs battery life, resulting in a lighter, more compact design with improved practicability and safety.
Implementation Method 1
a first angle sensor senses a rotation of the hip, the drive assembly controls the unlocking member away from the locking member, to unlock the locking member
Implementation Method 2
the second angle sensor senses that the thigh support assembly, the connecting base and the shank support assembly form a predetermined ergonomic angle
Implementation Method 3
the locking member is locked between the unlocking member and the first limiting member
Implementation Method 4
the drive assembly comprises a worm gear assembly, a third rotating shaft and a motor
Implementation Method 5
a shank drives the locking member to rotate or form support through a shank support assembly under the action of gravity
Data Source
AI summary
A knee joint mechanism includes a thigh support assembly, a connecting base, a shank support assembly and a locking mechanism. The thigh support assembly is fixed at a thigh of an exoskeleton robot, a first angle sensor is disposed on a hip, and power is provided from the hip. The connecting base is mounted with a second angle sensor. The locking mechanism includes a motor, a worm gear assembly, a locking member, an unlocking member, and a first limiting member. The unlocking member and the first limiting member firmly fix the locking member to maintain the thigh support assembly, the connecting base and the shank support assembly at an ergonomic angle. The motor drives the unlocking member to rotate through the worm gear assembly to realize unlocking. The second angle sensor controls the unlocking member to lock the locking block.