Low Profile Load Transducer with Cantilevered Beams for High Moment Capacity
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Solution Overview
Problem
Current low profile, multi-component load transducers have limited moment capacity and are sensitive to axial force offset, restricting their application in scenarios requiring higher moment ratings, such as robotic arms where forces and moments are transmitted through joints.
Innovation Solution
A low profile load transducer design featuring a central body with cantilevered beams supporting load cells configured to measure vertical, first shear, and second shear force components, allowing for a compact, high moment capacity while maintaining sensitivity to force components, achieved through a one-piece transducer frame with strategically arranged beams and strain gages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a low profile, small size transducer is used, then the transducer is compact and suitable for space-constrained applications, but the moment capacity is limited and the allowable offset for axial force is restricted to approximately half the diameter
Solution Approach 1:
The transducer is divided into multiple independent load channels (first load channel, second load channel, third load channel, fourth load channel), each measuring specific force or moment components. This segmentation allows each channel to be optimized for its specific measurement function while collectively providing high moment capacity and multi-component measurement capabilities in a compact form factor.
Solution Approach 2:
The patent transitions from single-component to multi-component measurement by adding spatial dimensions of measurement capability. The transducer measures not only axial forces but also shear forces and moments in multiple directions (Fx, Fy, Fz, Mx, My, Mz), effectively utilizing dimensional expansion to increase functional capacity without proportionally increasing physical size.
2Reliability
If the axial force acts centrally on the transducer, then the transducer functions correctly within specifications, but the allowable offset is limited to approximately half the diameter, restricting application flexibility
Solution Approach 1:
The transducer is designed with multi-functionality to handle both centrally applied forces and offset forces with high moment capacity. The combination of multiple load channels measuring different force and moment components enables the device to universally accommodate various loading conditions (central and offset forces) while maintaining measurement accuracy and reliability.
Solution Approach 2:
The patent replaces the conventional single-load-channel mechanical design with a multi-channel measurement system that uses strain gages and electrical circuitry to detect and differentiate between central and offset loading conditions, substituting mechanical constraints with electrical measurement capabilities.
3Measurement precision
If multiple strain gages are mounted on elastic elements to measure force and moment components, then measurement precision is high, but the transducer complexity and number of components increase
Solution Approach 1:
Multiple load channels and their associated strain gages are integrated into a single transducer body with a unified measurement system. The elastic elements and strain gage arrangements are combined to simultaneously measure multiple force and moment components, reducing overall system complexity while maintaining high measurement precision through coordinated multi-channel operation.
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 design significantly enhances moment capacity, enabling the transducer to handle moments approximately ten times higher than conventional load cells of similar size, with an increased allowable offset for force alignment, making it suitable for demanding applications like robotic joints.
Implementation Method 1
A transducer can incorporate one or more load channels. Each load channel measures one of the load components, and is comprised of one or more strain gages mounted to one or more elastic elements that deform under the applied load. An appropriate circuitry relates the resistance change in each set of gages to the applied force or moment.
Data Source
AI summary
A load transducer includes a central body portion; a plurality of beams extending outwardly from the central body portion, each of the plurality of beams including an end portion that is supported in a cantilevered manner from the central body portion; and a plurality of load cells, each of the load cells being disposed on one of the beams, the plurality of load cells configured to measure a plurality of force and/or moment components. In addition to being very accurate and reliable, the load transducer has a low profile and small size. This invention is easily manufactured using strain gage technology.