Design And Development Of High-precision Four-blade Slit System For Spallation Neutron Source Multi-physics Instrument

As the core component of the neutron instrument,the four-blade slit system,its positioning accuracy and repeat positioning accuracy will directly affect the overall performance of the neutron instrument.If the positioning accuracy and repetitive positioning accuracy of the four-blade slit are not high enough,the neutron beam may not fully illuminate the test sample or the neutron beam may form scattered scattering on the test sample because it is so large,so it seems very necessary to design the high-precision four-blade light.The current four-blade slit mainly uses open-loop control with a stepper motor and a ball screw,which has high transmission efficiency.However,it cannot be self-locked with a ball screw,and slight vibration will affect its accuracy.The positioning accuracy of each time meets the requirements.Based on the application status of the existing four-blade slit in other neutron spectrometers,a new neutron four-blade slit system is designed for the transmission and control of the four-blade slit.The main research contents of this article and the results are as follows:(1)The overall design goal of the four-blade slit is determined by the target user’s requirements for the experimental samples and the construction goal of the entire multi-physical instrument.According to the design goals,the four-blade slit system is researched to complete the design of its overall scheme Its key modules carry out corresponding research work.In the design of feed drive system,compare the advantages and disadvantages of various drive methods,and use professional finite element analysis software to perform dynamic and stress analysis on various schemes,optimize key size parameters,and complete the selection of various components;for further improvement The accuracy of the system is added with a feedback device to optimize the positioning accuracy and repeated positioning accuracy of the four-blade slit through a later algorithm;in the design process of the core component blade,the blade’s The parameters are optimized to obtain the optimal blade structure and material.(2)Research on the automatic control system of the four-blade slit system,sort out the control objects,divide the system control steps,determine the type of the upper computer,complete the design of the system control plan,select the key components of the control system,complete the circuit connection and the overall wiring design and simulation analysis of key modules,designing a control system thatcan be controlled remotely and locally.(3)Combining with the working principle of the four-blade slit,the research of intelligent control algorithm is carried out.In order to improve the positioning accuracy and repeat positioning accuracy of the system,an error compensation algorithm is designed.The feedback adjustment of the grating ruler and the controller reduces the error generated by the four-blade slit system.For the working principle of the feed drive system,a deceleration algorithm is designed to Eliminate the errors caused by the inertia of the motor itself.In order to improve the stability of the system,design a PID adjustment algorithm for the servo drive,and increase the stability of the system through the position loop and speed loop of the servo drive to reduce the external signal to control system interference.(4)Through the above four-blade slit mechanical structure and control system design,the construction of the four-blade slit experimental prototype was completed,and the designing experiment completed the test of the working performance of the four-blade slit prototype.Specific performance parameters verify the feasibility of the four-blade slit overall design.