Passive Gravity Compensation Linkage for Wearable Exoskeletons
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Solution Overview
Problem
Conventional gravity compensation apparatuses for upper limb exoskeletons are heavy, complex, and costly due to the use of batteries and actuators, limiting their practical application, especially for soldiers performing mine detection tasks that require high concentration and mobility on slopes.
Innovation Solution
A wearable gravity compensation apparatus with a non-powered design, featuring a main frame, rotatable links, a gravity compensation elastic member, and a support system allowing multiple degrees of freedom of movement, minimizing interference with the user's body and providing effective weight support without additional elastic members near the arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If actuators and batteries are used in gravity compensation apparatus, then the apparatus can actively compensate for load weight, but the system becomes heavy and complicated
Solution Approach 1:
The patent removes actuators and power sources from the gravity compensation apparatus, extracting the active control components that cause complexity and weight. The solution uses a passive elastic member (spring) that naturally provides gravity compensation without requiring external power or control systems, thereby resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The elastic member is configured to automatically compensate for gravity effects on the load without requiring external control. The system serves itself by using the inherent elastic properties of the spring to counteract gravitational forces, eliminating the need for actuators, batteries, and control electronics.
2Adaptability or versatility
If multiple actuators and links are used, then the apparatus can support load at any position, but the cost increases
Solution Approach 1:
The patent replaces expensive actuators and control systems with a simple, inexpensive elastic member and linkage mechanism. The passive spring-based system provides adequate gravity compensation at a fraction of the cost of active actuator systems, making the apparatus economically viable for practical applications.
3Device complexity
If a non-powered design is used, then the apparatus is simpler and cheaper, but it may not accommodate multiple degrees of freedom of movement
Solution Approach 1:
The apparatus is divided into multiple links (first link, second link, third link) connected by rotation axes, with each link contributing to a specific degree of freedom. This segmentation allows the passive elastic system to accommodate complex multi-DOF movements while maintaining simplicity and avoiding the need for actuators.
Solution Approach 2:
The patent introduces multiple rotation axes that intersect or are parallel to each other, adding dimensional complexity to the linkage mechanism. This enables the passive system to accommodate movements in multiple directions and planes, providing multi-DOF adaptability without requiring active control components.
4Reliability
If additional elastic members are placed near the arm, then gravity compensation is improved, but interference with the user's body increases
Solution Approach 1:
The patent merges the gravity compensation function with the existing linkage structure that supports the load. The elastic member is integrated into the linkage mechanism, combining structural support and gravity compensation functions into a single unified system, thereby eliminating the need for separate elastic members near the user's arm.
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
Enables free movement with multiple degrees of freedom while minimizing interference with the user's body, reducing fatigue and improving the usability of the apparatus for tasks like mine detection by distributing weight effectively without the need for external power sources.
Implementation Method 1
a gravity compensation elastic member having one end fixed to the main frame, and the other end fixed to the slider
Implementation Method 2
compensates for a weight of a load provided at an end of the apparatus
Data Source
AI summary
The wearable gravity compensation apparatus capable of multiple degrees of freedom of movement according to an example embodiment includes a main frame configured to be fixable to a back of a user, a base link rotatably connected to the main frame around a first rotation axis, a front extension link having one end rotatably connected to the base link around a second rotation axis intersecting the first rotation axis, the front extension link extending to a front of the base link, a rear extension link connected to the base link, the rear extension link extending to a rear of the base link, a guide positioned above the base link, the guide provided on the main frame, a slider configured to be slidable along the guide, a gravity compensation elastic member having one end fixed to the main frame, and the other end fixed to the slider.