Design And Realization Of Static Torque Test Bench

In the classical CNC machining process such as milling the torque between the tool and the workpiece can be measured to assist in evaluating the tool wear degree and improve the machining efficiency.Torque detection device through calibration to obtain high precision performance standard torque loading equipment is essential.The torque test bench provides controllable standard torque for the calibration process and can also be used for torque and life testing of bolts shafts transmissions and other products.Existing torque test bench products have been relatively mature but most software background is lack of torque numerical open interface and the calibration operation of one equipment may last several hours manual operation is time-consuming and laborious.This paper designs a static torque test bench to build the foundation of automatic torque detection system.The test bench system designed in this topic includes torque loading mechanical system and electrical control system.Complete equipment selection and theoretical analysis were implemented according to system working scope.The mechanical system consists of stepping motor,reducer,torque sensor,metal rod,magnetic powder brake and bracket,bottom plate and other connecting parts.The mechanical structure of connecting member,loading support and bottom plate were designed,and three-dimensional modeling was established,and the simulation calculation of stress,strain and deformation was carried out by using finite element analysis software,and the structural strength was checked to ensure the safety of the system.The electrical system also includes PLC(Programmable Logic Controller),sensor signal amplifier and magnetic powder brake controller.Design electrical system hardware circuit,using the ADC(Analog-to-Digital Converter)and DAC(Digital-to-Analog Converter)within PLC for sensor signal acquisition and magnetic powder brake controller locking.TIA Poral was used to complete the programming of system control software.Using PID algorithm,according to the sensor torque measurement value,the applied torque was ajusted,and the set torque was maintained.At the same time,the HMI(Human Machine Interface)interface of the upper computer was designed.The operator can set the process and add the steps of the static torque experiment on the upper computer.Finally finish the test bench hardware processing,assembly and debugging work.The test bench can complete the application and display of standard torque.Experimental verification of PID control performance,under the action of different torque,the maximum overshoot of the control system is not more than 12.62%,the establishment time is not more than 9.5s,the output static torque error is not more than 0.16 nm.Simulation torque calibration process experiment,under the condition of full scale 25 Nm,static torque continuous adjustment output experiment,the maximum overshoot of the control system is not more than12.65%,the establishment time is not more than 2.3s,the output static torque error is not more than 0.13 nm.