Design of an Embedded Torque Sensor : Based on Volumetric Strain induced Differential Air Pressure

University essay from Mittuniversitetet/Institutionen för elektronikkonstruktion

Author: Wen Qi; [2022]

Keywords: Torque; Electronics; Gas sealing; Pressure measurement;

Abstract: This paper proposes a torque sensor based on the differential air pres- sure measurement method using a new embedded structure. The pro- posed sensor design is an improvement over the previous sensor design. The mechanical sensitivity, resolution, and stress distribution of the new sensor are analyzed by finite element modeling. Based on the simulation results, a new mechanical sensing shaft body and its internal embedded parts were fabricated. The feasibility of the proposed embedded struc- ture is explored, and a sealing method based on this structure is pro- posed. In order to make the readout circuit of the differential pressure sensor embedded in the shaft body, the readout circuit PCB was rede- signed, and its power consumption was studied. To verify the design, the prototype sensor was measured at a static torque. The experimental results show that gas sealing of the sensor can be achieved using the proposed embedded structure and sealing method. The sensitivity of the mechanical design of the sensor is 249.23Pa/N·m, and the range is ±25N·m. The effect of using differential input to achieve common mode rejection is verified by applying an axial load to the shaft. The rotation test shows that using gas as the transmission medium can effectively avoid the influence of centrifugal force. The power consumption of the readout circuit is studied, and the results show that the sensor can work continuously for 34.7 days in sleep mode. 

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