Force Detection Device with Segmented Materials and Internal Wire Routing
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Solution Overview
Problem
Industrial robots' force detection devices face challenges in maintaining high detection accuracy due to the weight and thermal expansion of stainless steel components, which also suffer from unnecessary forces applied by external wires, leading to reduced accuracy.
Innovation Solution
The force detection device is designed with distinct materials for its components, allowing for reduced weight and thermal expansion management, and incorporates an inner bore section to route wires internally, minimizing external forces and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire first plate and the entire second plate are formed of stainless steel, then the coefficient of linear expansion is small and detection accuracy is improved, but the density is large and weight increases
Solution Approach 1:
The first plate is divided into a first pressing section and a first base section, while the second plate is divided into a second pressing section and a second base section. This segmentation allows different portions to be made of different materials - the pressing sections use stainless steel for thermal stability while the base sections use lightweight materials, thus resolving the contradiction between detection accuracy and weight.
Solution Approach 2:
Different regions of the force detection device are assigned different material properties. The pressing sections that require thermal stability are made of stainless steel, while the base sections that contribute most to weight are made of lightweight materials. This local differentiation maintains detection accuracy where needed while reducing overall weight.
2Ease of operation
If a wire is drawn out from the outer circumferential portion of the force sensor, then communication and power supply are enabled, but tension, bend, and twist occur when the arm moves, applying unnecessary force and deteriorating detection accuracy
Solution Approach 1:
The wire is routed through the hollow interior space of the force detection device, nesting the wire path within the device structure itself. This internal routing protects the wire from external mechanical stresses during arm movement, eliminating the contradiction between wire connection and detection accuracy.
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 configuration enhances the detection accuracy of the force detection device by reducing weight, managing thermal expansion, and minimizing unnecessary forces, leading to improved performance in industrial robots.
Implementation Method 1
the sensor element can detect the external force by outputting electric charge corresponding to the external force
Implementation Method 2
The first plate including the first pressing section and the second plate including the second pressing section are integrally formed of stainless steel or the like having a relatively small coefficient of linear expansion. Therefore, it is possible to reduce the influence of thermal expansion of the first plate and the second plate.
Data Source
AI summary
To obtain a force detection device and a robot light in weight and having excellent detection accuracy, a force detection device includes a first member, a second member joined to the first member, and a piezoelectric element joined to the second member. A material forming the first member is different from a material forming the second member. The first member is formed in a plate shape. The piezoelectric element and the second member are disposed at an end portion of the first member. A through-hole is formed in the center portion of the first member.