The Design Of Motion Control System Of Positron Emission Tomography (PET)

Positron emission tomography (PET) is the functional imaging equipment with good specificity among the modern nuclear medicine instruments. It can make the noninvasive diagnosis of coronary artery disease (CAD), brain disease and tumor in their early changes. Therefore, it plays a very important role in the field of modern iatrology. Based on the introduction of the systematic structure and working principle of PET, the thesis mainly described the realization of the partial function in the medical bed motive control system.In the first part of this thesis, the characteristics, working principle and mode designs of the PET system were described with the emphasis on the role of motion control system in the PET system. Then after the comparing with some motors, the projects of hybrid closed loop position servo system with AC synchronization servomotor were developed in the second part.The third part mainly described the hardware design of patient bed motion control system. First, this thesis introduced the character of the microprocessor 80C196KC and its functions of high speed input(HSI) and high speed output(HSO) units. Then this thesis described some main modules of this system, such as the minimum system circuitof 80C196KC, the pulse generator circuit, position detection circuit, switch signal process and serial transfer circuit. In the fourth part, based on the moving request of the patient bed, this thesis introduced the control idea how to finish the system's tasks, including the mode of speed regulation with the special speed control curve graph.In the fifth part, after analyzing the problem of the system's precision detailedly, this thesis introduced some designs to compensate the accuracy. Then, aimed at orientation precision problem in the bed due to the geometric deformation, this thesis put forward the compensatory approach and comparing result.In the last part, the conclusion and expectation of this thesis was given.