Design And Research On Flexible Needle Drive Mechanism And Controller

As in the process of medical puncture, sometimes it needs to drive round some important organs, nerves or bones. And the traditional sense of rigid straight needle is difficult to realize this kind of action. So undoubtedly using the flexible needle is the best choice if you want to achieve the ideal treatment purposes.Nowadays,we are still in the early stages of the flexible needle puncture in our country.It is in the way of PC controlling driven mechanism to control fexible needle puncture.Thus it needs to configure the PC machine and control software. So it is expensive, bulky and inconvenient to use. Therefore, it has great significance to research a low-cost, small size, flexible needle driven mechanism and controller.First of all, flexible needle driven mechanism is designed based on the Principles of flexible needle puncture and by using natural step angle 1.8°step motor as driven motor and by using ball screw drive mechanism as the straight line motion mechanism of needle driven mechanism. Secondly, controllerreset circuit, communication circuit, clock circuit and other peripheral circuits are designed based on modularization.And Sunplus SPCE061A16 bit processor is selected as the core of the overall program.Then for the features of upper and lower level computer hierarchical control, based on Sunplus unSP2.0 build enviroment, using two timers’interrupt function of Timer A and Timer B to make I/O inversion to generate PWM wave to control step motor,I prepare a lower level computer program that can realize the control of the speed and locationof flexible needle’s rotation and insertion or other motions.And control software of upper level computer is programed in the Visual C++6.0 enviroment. At last, the experiment of flexible needle puncture and the error analysis is made by using the controller I developed.The result shows that this controller is stable, comprehensive and has high control accuracy. The error of linear feed displacement of driven mechanism is controlled less than 0.02 mm, and flexible needle straight, single arc, two arcs movement are all within the error of 1.28 mm. The actual paths fit the theoretical path well.It meets the needs of flexible needle puncture and lays a good foundation of the widely use of flexible needle puncture.