Torque Control System Design

With the vigorous development of the aerospace industry,high-volume,high-density launches have become the norm.Spacecraft capabilities have become more complex and there are more and more internal equipment.As a result,more and more RF cable assemblies are connected between devices.These cable assemblies are Before installation,the vector network analyzer must be used to test the electrical properties of its standing wave,insertion loss,and group delay jitter.During the test,the tester needs to connect the two ends of the cable assembly to the two ends of the vector network analyzer,and then use the mechanical torque wrench to fasten it.After the test is complete,the tester must disassemble the cable assembly.When faced with hundreds of cable assembly test tasks,the use of traditional mechanical torque wrenches is very inefficient.Therefore,an electric torque wrench must be designed to reduce the operator's labor intensity and improve labor efficiency.The produced torque control system,together with the structural designer,finally completed the debugging of the product and finally completed the product appraise.Torque control system must realize precise torque control(satellite cable assemblies have severe torque requirements),and realize design factors such as positive and negative rotation of the motor(need to be tightened and disassembled during testing).The output current of the DC motor is proportional to the torque.The current flowing through the motor is sampled,and the sampled current is processed,amplified,and compared with the threshold value.If the threshold value is reached,the control circuit will cut off the motor power supply system to achieve a closed-loop control system,thereby achieving torque control.In the design process,the factors affecting the torque control accuracy are analyzed one by one.Including the setting accuracy of the threshold and the temperature coefficient of the sampling resistor,the torque control accuracy is less than 0.06 Nm.At the same time,the controlprogram analyzes the collected current sampling data and removes the maximum and minimum values.The data is weighted and averaged to be output to a threshold comparison system to implement software filter design.After the preliminary research and project establishment,data access,circuit debugging,and mid-term review work,the problems encountered in the previous period were overcome and a large number of tests and improvement measures were carried out to form the final circuit.Through the study of the torque control system,it can be seen that this set of torque control system with higher sensitivity combines mechanical structure,and passes the torque calibration of the electric torque wrench through the torque calibration equipment,achieving the design expectation and having a wide range of torque control(0.8Nm~2Nm),high torque control accuracy.The electric torque wrench developed by the project has high control precision and smooth operation,and it fills in the gap that there is no electric torque wrench when the cable assembly is disassembled.Currently,it is gradually put into scientific research and production,which will also greatly improve the labor efficiency and reduce the operator's Labor intensity.