Design And Research On Collimator Subsystem For Medical X-ray Machine

X-RAY collimator subsystem is the important part of X-ray machine, and its main function is confine the scope of X-ray beam, to reduce the radiation harm to Patients; Another function is realizing the multi-scope exposure on one film working with the film motion and shielding system. Its performance is crucial to enhance the level of automation of X-ray machines, Achieve digital control of whole sets and to reduce radiation injury to patients.Firstly, We compared the domestic with the foreign products,analyzed the advantages and disadvantages of existing domestic products;To reduce patients ray radiation, facilitate the operation and enhance the level of automation,at the same time, considering the goal of the sets,we made function goal of collimator subsystem.Secondly, on the basis of summing up existing products ,we designed the mechanics part. In the design, gear and spline were adopted, so symmetrical movement of (collimator's) lead Gates can be achieved easily, mechanical structure became more compact . Worm was adopted to adjust mirrors accurately, and deflection of mirrors can be prevented in case of the external impacts or vibrations.Thirdly, we selected the type of driving motor, analyzed control approach, and chose reasonable control way. A micro-controller based on 89C52 and LM629, LMD18200 is presented in the paper. With the help of the motion controller it not only simplifies the design of the hardware and the software of the control system but also enhances its reliability and performance. It is help to shorten responsive time, upgrade precision, and easy to realize automation and digital control. Incremental - coding devices is used as Position feedback device, meanwhile, magnetic field sensor AD22151 is used as position sensor to demarcate movement origin, which have features of the high sensitivity, small size, non-contact.Finally, the paper introduces the design of the software. All programs are compiled in form of module, which will convenient for designer to debug and update. The flow charts of principal modules are presented in the paper.