The Research Of Miniaturized Joint Torque Sensor

The manipulator must be sensitive to sense changes of the force from the end, in order to provide accurate feedback to the control system, and the sensor is an important factor in achieving this link. The various joints are required to obtain the information feedback about the joint torque fast and accurately when the exoskeleton shake operation main hand are moving. Thus it is particularly important to improve the performance of the whole organization by designing the applicable sensor according to the characteristics of the exoskeleton joint motion to meet the operation of the entire system. In view of the study about the exoskeleton shake operation main hand in our experiment center, a small torque sensor that is applicable to the exoskeleton structure is put forward in this paper.The design research of the torque sensor is implemented according to the current research related to sensor of the exoskeleton joint and the design functional requirements of the exoskeleton joint interface and the sensor elastomers. The main work of this paper includes:1、This thesis proposes a lightweight, overall mechanical structure model with shaft torque sensor, combined with exoskeleton teleoperation main hand structure and sensor design guidelines. The structure size is determined by comparing the structural designs of a variety of elastomers and optimizing the overall structure with finite element analysis.2、The torque detection principle is analyzed and calculated for the forces of sensor elastomers. This paper designs the scheme of measuring bridge and calculates the sensitivity of the circuit. The theory of linear equation between the output voltage and load torque variables is deduced by analyzing on the scheme of the strain gauge paste.3、Embedded amplification filter circuit module is proposed to improve the signal-to-noise ratio of the detection circuit. The circuit module is designed by using high-accuracy and low-power amplifier chip and a differential filter circuit. Based on the sensor’s structure, design the embedded circuit module, arrange the wires and analyze the processing technology. The circuit module is proved to manage to amplify feeble signals accurately by analyzing the effectiveness of the module with analog circuit experiments.4、The thesis designs a sensor signal acquisition system by using a high-performance ARMSTM microprocessor and pluggable serial communication interface. It can read signals on PC by setting a high conversion accuracy and sampling frequency for signal rapid acquisition. Through constructing experiment platform for experimental verification, this experiment proves the validity of the signal acquisition system, and the high signal transmission speed can well meet the requirements of real-time sensor.5、By building the sensor’s testing and calibration experiments platform and verifying the proposed process parameters, measurement circuit, embedded module and signal acquisition system. At the same time the reduction method is used for sensor modal analysis, the natural frequency and modal parameters are concluded. Combined with the calibration data, natural frequency and mode shape parameters, it provides an effective basis for the sensor’s subsequent dynamic performance analysis and optimization.