Annular Flexure Torque Sensor with Interleaved Heads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional torque sensors in robotic devices are thermally sensitive and prone to offsetting during torque overload, limiting their accuracy and reliability.
Innovation Solution
A flexure-based torque sensor design featuring an annular flexure hub with interleaved stationary and rotatable heads, coupled with sensors to detect rotational movements and calculate torque, providing overload protection and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional torque sensors are used in robotic joints, then torque detection function is provided, but thermal sensitivity and offsetting during torque overload occur, reducing measurement precision and reliability
Solution Approach 1:
The torque sensor is divided into multiple independent heads (first stationary head, second stationary head, first rotatable head, second rotatable head) that can independently detect torque. This segmentation allows the system to continue functioning even if one head experiences overload, improving reliability while maintaining measurement precision through combined readings from multiple heads.
Solution Approach 2:
The flexure hub structure provides inherent overload protection by mechanically limiting the torque transmission to predetermined levels. The flexure elements are designed to deform or disengage under excessive torque, preventing permanent damage and offsetting errors before they occur, thus maintaining sensor reliability and measurement accuracy.
2Measurement precision
If traditional torque sensors are used, then torque detection is enabled, but thermal sensitivity causes measurement drift, reducing measurement precision
Solution Approach 1:
The patent replaces traditional mechanical strain gauge-based torque sensing with a flexure-based mechanical advantage system combined with position sensing. This substitution eliminates the thermal sensitivity issues associated with conventional strain gauges while maintaining accurate torque measurement through the relationship between rotational position and torque calculation.
Solution Approach 2:
The invention changes the measurement parameter from direct strain measurement (which is thermally sensitive) to rotational position measurement of the flexure hub. By measuring angular position instead of strain, the system becomes insensitive to thermal effects while maintaining torque measurement precision through mathematical relationships between position and torque.
3Measurement precision
If multiple sensor heads are implemented in the flexure hub, then measurement precision and reliability are improved, but device complexity increases
Solution Approach 1:
Each head in the flexure hub serves multiple functions: structural support, torque transmission, and positional sensing. The stationary and rotatable heads work together as integrated units that simultaneously provide mechanical function and measurement capability, reducing overall device complexity despite having multiple sensing elements.
Solution Approach 2:
The patent merges the structural components with the sensing components into integrated heads. The flexure hub structure itself serves as both the mechanical element and the sensing element, eliminating the need for separate structural and sensing components, thus reducing device complexity while maintaining multiple sensing points for improved precision.
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 flexure-based torque sensor effectively measures torque with enhanced accuracy and reliability, preventing thermal sensitivity and offsetting issues, thereby improving the precision of robotic joint operations.
Implementation Method 1
Flexure based torque sensor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An example device may include an annular flexure hub including a first stationary head, a second stationary head, a first rotatable head, and a second rotatable head. Each of the heads comprise an annular sector of the flexure hub, and the first and second stationary heads are interleaved between the first and second rotatable heads. The device may also include a stationary housing coupled to the first stationary head and the second stationary head of the flexure hub. The device may also include a first sensor positioned adjacent to the first rotatable head of the flexure hub, and a second sensor positioned adjacent to the second rotatable head of the flexure hub. The device may also include a rotatable housing coupled to the first rotatable head and the second rotatable head of the flexure hub.