Design And Research Of Telemetry Torquemeter Based On Bluetooth Technology

In practical project,there are lots of machine components upon which the torque are acted,such as steering axle,transmission shaft,feed rod,principal axis of the electric motor and principal axis of the hydroturbine,etc.With the improvement of the mechanical industry,automotive industry,power and energy industry,the electric motors of large machine are developing to the high power,high reliability,high efficency and automated management.The security and reliability of these large rolling components play an important role on the normal opration of the machine.So to monitor the performance parameter,especially to monitor the torque is very important.In view of this,combining electrical strain gauge technique and bluetooth technology,this paper designs a telemetry torquemeter.At present,there are three main methods to measure the torque:transmission method,equilibrant method and power convertible method.In these three methods, transmission method and equilibrant method are more convenient and more accurate than power convertible method,power convertible method is an indirect method,people only use it when they can not measure torque directly.This paper chooses transmission method to measure torque.Transmission method uses the relationship of variation of the physical parameter and torque to measure the torque.Because this paper aims to design a torque sensor which is used on the high speed rolling shaft,to equip the wires is very difficult.In view of this,this paper chooses telemetry strain measurement,uses wireless telecommunications to fulfill the sending and receiving of the signal.Telemetry strain measurement applies to moving and rolling objects.This paper makes a comparation between several mainstream wireless telecommunications,and chooses the bluetooth technology which has a good performance.The main charateristics of bluetooth technology:it can implement bluetooth protocol repertory inside,directly finish inquiry, authentication,connection and communications function on HCI.As the data packing, unpacking,sending,receiving and checking of bluetooth are transparent for users,so it is very convenient to fulfill bluetooth communication.Between MCU and bluetooth model, bluetooth model and PC,this paper uses serial communication.In respect of power supply,there are two main traditonal mehods:one is to use collecting ring,and the other is to use battery.But these two methods all have limitations,in view of this,this paper uses a new power supply system,Contactless Power System.Contactless Power System uses electromagnetic coupling to transport electrical energy,it do not need connection of electric lines,so this system can transport electrical energy in some bad circumstances.After designing the electronic hardware of the system,this paper also designs a mechanical component to carry the electronic hardware.This component makes the installation of the PCB on the shafts with varied diameter much easier,on the other hand,it solves the problem of the PCB on the high speed rolling shaft suffers huge centrifugal pull.According to the electrical strain gauge technique,this paper analyzes the working principle of the electric resistance strain gauge,and get the relationship between the output voltage of the bridge and the strain.Then,designs the hardware circuit of the telemetry torquemeter based on AT89C52 singlechip,including signal amplifying circuit,A/D converting circuit,sending and receiving circuit of the bluetooth,power supply circuit and the interface circuit btween the bluetooth module and PC.According to the function and requirement of the system,this paper designs correlative software program,and then simulates the hardware and software of the signal collector in Proteus.The simulation result proves the telemetry torquemeter which this paper designed is accurate and reliable.The telemetry torquemeter that this paper designed has many characteristics,such as high precision,reliable and user-friendly,it is meaningful to the research and development on the torquemeter.