The principle and composition of the force sensor is composed of three parts: one or more elastomers that can produce deformation after being subjected to force, a bridge circuit (such as a Wheatsden bridge) that can sense this deformation, an adhesive that can fix the resistance strain gauge on the elastomer and conduct the strain amount, and a sealant that protects the electronic circuit.
Chinese name: Force sensor
Material: aluminum alloy, alloy steel and stainless steel
Material characteristics: consistent deformation and deformation recovery, anti-corrosion performance
Influencing factors: creep of the elastomer and sensor temperature Working process After being affected by external forces, the strain gauge stuck on the elastomer will cause deformation and cause resistance changes. The resistance changes cause the Wheatsden bridge to lose balance and output a linear proportional to the external force.
Material: Elastomer
The elastic material of the force sensor is generally made of metal. Most of the materials that can be selected are aluminum alloy, alloy steel and stainless steel. The alloy material has both stiffness to ensure consistent deformation and recovery, and has good weather resistance and corrosion resistance. The main requirement of an elastomer is to be able to accurately transmit the stress information and maintain deformation consistency and complete resetting when the same stress is applied. Strain gauge and resistance element materials The composition of resistance strain gauge is complex and is a composite manufacturing product. The combination of the substrate of the strain gauge and the strained copper is changing rapidly. According to its strain requirements, there are currently about a thousand products. Generally, the substrate uses polymer strain material with high purity Conco copper. Concoco on the substrate is optically treated and etched resistive grid wires with different induction deformations. Therefore, the quality of the resistance strain gauge is not only related to the base material and the purity of the composite metal, but also to factors such as composite process, etching technology and processes, etching chemical materials, post-treatment processes and materials. Material of patch adhesive The adhesive for resistive strain gauge patches mainly uses two-component polymer epoxy series adhesives. The performance of polymer chemical products is closely related to the physical and chemical indicators of each component, such as purity, structure and size of the molecular chain, storage time, component ratio, molecular modification, mixing method, mixing and maturation use time, curing time, curing temperature, additives and percentages, etc. Material of sealant In the early stages of the force measuring sensors where welding technology and insufficient equipment are used, special silicone rubber sealant series are used. Giardo rubber has long-term chemical stability, so it has excellent properties such as corrosion resistance, moisture resistance, aging resistance, insulation resistance, and has long been the first choice product for all sealants. The wire material of the force sensor is still part of the force sensor. The metal material of the force sensor wire is made of, and the quality differences of the household electrical appliances are experienced by everyone. After all, the conductor is a road for bridge power supply, signal output, and long-line excitation voltage compensation. The silver-plated wire is better than the copper wire, and the copper wire is better than the aluminum wire, and its effect is self-evident. With more and more interferences such as various high-frequency and radio waves, excellent shielding of force measuring sensors is also an important method to protect signal stability. In addition, environmental erosion, insect and rat invasion, fire and flame retardant, etc. also require the materials of the sensor protection layer to be anticorrosive, insect-proof, fire-proof and explosion-proof, and even armor protection, casing protection and other methods are required. Wire sealing materials and methods, and each component of the force sensor will affect the final technical performance of the sensor. Some force sensors only use simple fixing methods to avoid the movement of the sensor wires and damage the electronic circuit fixation of the sensor. Some force sensors with very short conduction distances may even be fixed only by glue seals. However, if the force sensor with larger volume and larger weight is not properly fixed or sealed, it is the bottleneck that the force sensor is most likely to cause failure. Especially when installing seal head fixing wires, the material of the fastener and the fastening force will also affect the final technical performance of the force sensor. Observers found that few fasteners are used to install sealing adhesives, which can avoid residual stress caused by fastening force fixation and will not cause leakage due to insufficient fastening force.
