Elastic Gear Module for Compact Series Actuator Rigidity Tuning
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Solution Overview
Problem
Series elastic actuators face challenges in adjusting the rigidity of springs when miniaturized, requiring additional space and configuration due to separate components like reduction gears and springs, making it difficult to achieve precise control and compact design.
Innovation Solution
The implementation of an elastic gear module with a gear, output body, and elastic body, where the elastic body is connected to the gear and output body, allowing for adjustable rigidity through series or parallel connections of elastic bodies, and made from materials like stainless or aluminum alloys for enhanced torque capacity and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate reduction gear and spring components are used, then torque measurement capability is achieved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the reduction gear and spring into an integrated elastic gear module where the spring is embedded within the gear structure. The gear includes elastic teeth that deform under load, eliminating the need for separate spring components while maintaining torque measurement capability through the elastic deformation of the gear teeth themselves.
Solution Approach 2:
The elastic gear module serves multiple functions simultaneously: it provides mechanical advantage through gear reduction, stores elastic energy for torque measurement, and acts as a mechanical element for force sensing. This multi-functionality reduces the overall number of components needed in the series elastic actuator system.
2Force
If traditional springs are used in miniaturized actuators, then torque capacity is maintained, but rigidity adjustment becomes difficult and space requirements increase
Solution Approach 1:
The patent enables rigidity adjustment by changing the elastic properties of the gear teeth through material selection and geometric design. By modifying parameters such as tooth thickness, height, and curvature, the effective spring constant can be tuned to achieve desired rigidity levels while maintaining compact dimensions and adequate torque capacity.
Solution Approach 2:
The elastic gear may utilize composite material structures or graded materials to achieve optimized mechanical properties. This allows simultaneous achievement of high torque capacity and adjustable rigidity by controlling the material composition and distribution within the gear structure.
3Volume of moving object
If compact design is pursued, then device size is reduced, but rigidity adjustment capability is compromised
Solution Approach 1:
The spring is nested within the gear structure, with the elastic elements embedded in the gear body or between gear teeth. This nesting arrangement allows the spring to occupy space that would otherwise be structural material, achieving compact integration without sacrificing rigidity adjustment capability.
Solution Approach 2:
The patent explores alternative spatial arrangements where the elastic elements are positioned in three-dimensional space within the gear volume. By utilizing vertical stacking or radial arrangement of elastic elements, the design achieves rigidity adjustment capability within a compact footprint by exploiting the third dimension.
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
This design enables a compact series elastic actuator with adjustable rigidity, improving torque capacity and reducing weight, while maintaining high processing ease and low cost, facilitating precise control and miniaturization.
Implementation Method 1
an elastic body connecting the gear and the output body. The elastic body may include an outer ring fastened to the gear, an inner ring positioned inside the outer ring and fastened to the output body, and a deformation portion connecting the outer ring and the inner ring and deforming elastically
Data Source
AI summary
A series elastic actuator includes a gear configured to rotate, an output body configured to rotate by the gear, and an elastic body connecting the gear and the output body. The elastic body may include an outer ring fastened to the gear, an inner ring positioned inside the outer ring and fastened to the output body, and a deformation portion connecting the outer ring and the inner ring and deforming elastically. The elastic body may include a plurality of elastic bodies connected in parallel or in series.