| Spindle is the core functional unit of high-precision machine tool, thus its thermal state directly affects the accuracy of machine tool. On the intensive study of the theory of wireless and passive surface acoustic wave(SAW) sensor technology and wireless communication system, this paper proposed a temperature monitoring system for machine tool spindle based on the passive and wireless surface acoustic wave sensor, referring to the issue of spindle’s thermal state monitoring and thermal displacement compensation. An integrated spindle temperature monitoring system(STMS) has been designed and its validity has been verified experimentally. The main work is presented as follows:(1) The sensing principle and motivation property of SAW sensor are analyzed in details and then the resonant SAW sensor is chosen as the sensing element of STMS. Next, the advantages and disadvantages of all kinds of radio frequency(RF) transmit-receive systems are studied to figure out 1he circuit frame of the interrogator, with the account of resonant SAW sensor’s communication features.(2) The hardware and software systems of the interrogator of SAW sensor monitoring system have been designed and developed. Schematics and PCB boards of every circuit module are implemented dependently. Then the disperse modules are integrated into one interrogator system after the functions of them has been well tested. On the in-depth study of chips’structure, the control codes of the system is programmed and upper-computer software with flexible display function is developed.(3) SAW temperature monitoring system’s performances are tested. With the synthetic control of RF switch, synthesizer and superheterodyne receiver, noise in the receive channel is eliminated, consequently the interrogator achieves good communication with SAW sensors. Then the demodulation and analysis performances of interrogator are detected with the frequency scan experiment simulating the communication process between SAW sensor and interrogator. The results show that the accuracy of the system can reach 0.1 degree centigrade in a certain range.(4) Experiments are conducted employing the temperature monitoring system on machine tool spindle to examine the validity. Factors affecting the communication quality of monitoring system are studied experimentally, and the results are taken advantage of to optimize the configuration mode of the monitoring system. Finally, spindle’s rotation experiment is carried out with monitoring system installed due to the optimization scheme. The result indicates that the SAW sensor temperature monitoring system could perform well, effectively monitoring the thermal change of the rotating spindle.The achievements of this project provide a new technical method for the state monitoring of the machine tool spindle and the similar structures. |
PDF Full Text Request