植牙輔助裝置之設計與控制

Abstract

植牙手術於現今醫療中仍無健保給付，且整體過程需花費長時間，若不慎手術失敗不僅影響其功能亦不美觀，並可能衍生出許多的醫療糾紛。本研究旨於運用電腦輔助系統和微小輔助機構使植牙手術成功率增加，對該機構之定位與植體植入時所需之螺桿馬達的轉動角度控制。 研究主要分為兩個面向，超音波馬達致動平台改良與控制設計，以及植體手術所需之線性步進馬達進給深度控制器和Z軸機構設計；前者係以六個超音波馬達所構成之六軸致動平台，由六個超音波馬達間的作動組合，使其可完成XY兩軸方向的平移和旋轉，以利於植牙時所需之各種角度的改變與動作，為使其可精密定位和多軸控制效果，而設計了雙回授比例積分微分控制器，以改善動件定位控制過程中Overshoot的情形發生，並且縮短Settling time。 後者則為利用線性步進馬達作為植牙輔助機構之Z軸使用，其將同時具備旋轉和線性兩種運動方式所組合的螺旋運動，藉由此一運動模式來將植體鎖入齒槽骨中。為避免在植體植入過程中因為深度過深而傷害到骨頭，因此，設計一控制器來控制螺桿的旋轉角度，並經由換算後進而間接控制線性步進馬達的螺桿位移深度。本研究已經設計製作原型機，以便測試性能。

Dental implant surgery in today’s medical still has no national health insurance benefits, and the whole process takes a long time. If the surgery accidentally failed not only affects its usefulness or beauty, but also may incur a lot of medical disputes. The objective of this study is using computer-aided systems and device to increase the success rate of the implant surgery, by controling devices position and the angle of motor rotation. This study includes two main parts. The first is the design of ultrasonic motor (USM) controllers and improving the motor actuator stage. The other one is the design of a Z-axis actuator and its controller. The actuator stage consists of six ultrasonic motors to become a six degree-of-freedom actuator stage. Displacement and rotation along X and Y axes are achieved by using six USMs actuation combination for variations of the displacement and angle when implant surgery needs. This study designs a double-feedback PID controller for the USM stage to improve the position accuracy and to reduce settling time and overshoot in transient response. Concerning the Z-axis actuator, this study uses a linear stepping motor that implants with screw motion. To prevent the lead screw, which is on the stepping motor, implanting too deep and getting hurt, this study designed a controller to control the lead screw depth by calculation based on the rotary angle and pitch of the lead screw. The author has designed and fabricated a prototype in order to measure device performance.