Single Actuator Exoskeleton with Differential Drive Mechanism
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Solution Overview
Problem
Existing lower-limb assistance exoskeletons are bulky due to multiple drive motors or hydraulic/pneumatic drives, leading to increased weight, power consumption, and instability, making them difficult for a single person to wear and store.
Innovation Solution
A lightweight human body assistance device based on a single drive actuator, featuring a rigid support, a drive actuator, and interconnected left and right drive mechanisms, which use transmission cables and an auxiliary transmission cable to coordinate the movement of both legs with a single drive source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple drive motors are used to drive left and right legs alternately, then the assistance function is improved, but the overall weight and power consumption increase
Solution Approach 1:
The patent combines multiple drive motors into a single drive motor that controls both left and right legs through a differential mechanism. The single motor's output is transmitted through a differential to two drive rods, which then drive the left and right legs alternately. This merging approach maintains the assistance function while significantly reducing weight and power consumption compared to using separate motors for each leg.
Solution Approach 2:
The single drive motor performs multiple functions by driving both left and right legs through the differential mechanism. The differential mechanism enables one motor to provide alternating drive to both sides, making the single motor universal for bilateral leg assistance. This multi-functionality eliminates the need for separate motors while preserving the assistance capability for both legs.
2Power
If multiple drive motors are used, then the drive capability is improved, but the system stability deteriorates due to increased complexity
Solution Approach 1:
By merging multiple drive motors into a single motor with a differential mechanism, the patent reduces the number of independent control systems from two to one. This consolidation simplifies the control architecture, reduces the complexity of coordinating multiple motors, and improves system stability while maintaining the drive capability through the mechanical differential that naturally coordinates bilateral movement.
3Power
If hydraulic or pneumatic drives are used, then the drive efficiency is improved, but the equipment weight increases significantly
Solution Approach 1:
The patent replaces hydraulic or pneumatic drive systems with a mechanical drive system using a single motor and differential mechanism. This substitution eliminates the need for heavy hydraulic pumps, reservoirs, or pneumatic compressors and tubing, significantly reducing equipment weight while maintaining drive efficiency through the direct mechanical connection of the motor to the differential and drive rods.
4Power
If hydraulic or pneumatic artificial muscles are used, then the actuation capability is improved, but the reliability deteriorates due to rust and malfunction from environmental exposure
Solution Approach 1:
The patent replaces hydraulic or pneumatic artificial muscles with a solid mechanical drive system consisting of a motor, differential, and drive rods. This substitution eliminates components that are susceptible to rust and environmental damage, improving reliability while maintaining actuation capability through the robust mechanical transmission system that is less vulnerable to environmental factors.
Data Source
AI summary
A lightweight human body assistance device based on a single actuator, includes a drive actuator, and a first drive rod and a second drive rod respectively set on two sides of the drive actuator. The drive actuator includes a stator housing and a rotor shaft rotatable relative to the stator housing. The first drive rod rotates with the stator housing, and the second drive rod rotates with the rotor shaft. One side of the first drive rod is connected to a first drive back end that matches a leg on one side of the human body, and one side of the second drive rod is connected to a second drive back end that matches a leg on other side of the human body.