Research On Design Of Sensor And Measurement For Railway Point Machine Actuator Rod

Turnout is an important device to change the direction of train.China has a vast territory and many railway intersections.This results in a large number of turnouts and high working frequency in China.Turnout is one of the three weak links of railway.It has the characteristics of short life,complex structure,low speed and high maintenance cost.Turnout generally includes railway point machine,switch rail,point rail,stock rail,frog and guard rail.The railway point machine is the core electrical equipment for turnout transform.It drives or pulls the switch rail by the motor to make the switch rail and the stock rail close or separate,so as to realize the function of changing track.The railway point machine not only has the function of moving the switch rail position,but also has the function of realizing the switch locking and indicating the switch position,so the health of the railway point machine is directly related to the stable operation of the turnout.Driving force is the most important and basic parameter in the execution process of railway point machine.Enough driving force is the most basic requirement to complete the transfrom.Based on the importance of railway point machine,this paper carries out a series of research around the force measurement of actuator rod.In this paper,through the study of the stress concentration of the hole and the establishment of a simulation model of the actuator rod of the railway point machine,the stress and strain distribution of the actuator rod is obtained,and the sensor placement point is determined.The sensor is installed in the actuator rod of the point machine,and the voltage signal is obtained through the transmitter to realize the measurement of the force state of the actuator rod of the point machine.The specific work is as follows.Firstly,based on the related theories of elastic mechanics,the stress concentration of the plane hole was simulated and explored;the assembly model of the actuator rod was simulated to determine the installation position of the sensor.Secondly,the sensor based on the metal strain gauge is designed,and the assembly model of the sensor actuator rod is simulated.The feasibility of this method is verified by experiments.Thirdly,the Piezoresistive effect and applications of semiconductor resistors are studied.This paper designs an actuator rod force sensor based on semiconductor resistance,designs a sensor elastic body sensitization structure,and designs its matching transmitter to form an actuator rod force measurement system,which solves the measurement caused by the stiffness of the actuator rod problem.Finally,the static characteristic curve of the sensor is obtained by calibrating the sensor.The sensor linearity,repeatability and other parameters are obtained.The sensor was installed on the experimental platform of the railway point machine,and the dynamic force curve of the actuator rod was drawn to verify the dynamic characteristics of the sensor.Through comparison and analysis with standard sensors,the measurement system can effectively measure the force state of the actuator rod.In short,this paper proposes a new method for measuring the force of the railway point machine’s actuator rod,and develops a set of device for measuring the force of the railway point machine’s actuator rod.Experiments have verified that the measured results are in good agreement with the actual driving force curve,and the output signal has a high signal-to-noise ratio,which can meet the measurement requirements for the health of the railway point machine actuator rod.