Design And Implementation Of Multi-axis Linkage Controller For Industrial Computed Tomography

Industrial Computed Tomography (CT) is one of the universally acknowledged optimum detecting methods. With the development of industrial CT, the variational work pieces and complex application environment call for a higher requirement for industrial CT, including the linkage precision, versatility, real time property and so on. As a kernel of industrial CT, the multi-axis linkage controller determines whether the above requirements can be realized. Currently, limited to control mode, the domestic multi-axis linkage controller is difficult to improve its control precision, real time property and expansibility. Meanwhile, the controller has high development costs and is harder to upgrade maintenance. In order to solve these problems, design and implementation of multi-axis linkage controller for industrial CT is carried out in this paper.Firstly, this thesis has researched mature multi-axis linkage motion control strategy and multi-axis linkage controller, and then analyzed their deficiency and difficulty in the application of industrial CT. The deficiency and difficulty are manifested in five aspects: linkage precision, expansibility, real time property, costs and upgrade maintenance.Based on the research of industrial CT's scanning mode and motion control methods, this paper has realized the second and third generation scanning mode, which are commonly used in industrial CT, and extracted multi-axis linkage control parameters, then proposed motion controller's design scheme, which uses microcontroller and FPGA to realize controller's hardware, uses time dividing interpolation algorithm to improve linkage precision. In controller's design, FPGA has been customized motion control chip, andμC/OS-II has been chosen to be controller's real time operating system.Finally, this paper has completed the realization of the design scheme. In realizing process, the time dividing interpolation algorithm and industrial CT's scanning control were researched especially. Through interpolation calculation and FPGA implementation of interpolation algorithm, and the application layer's four task, which are system monitor, motion control, path planning and command parser, controller's linkage precision and real-time response capability are improved, meanwhile, upgrade maintenance of controller's hardware and software is becoming easy. On experimental platform of industrial CT, controller's multilayer second generation scanning was made, and the results show that the multi-axis linkage controller for industrial CT, based on microcontroller, FPGA and time dividing interpolation algorithm, can meet the requirements of CT scanning control. It has advantages in the linkage precision, multi-function expansion and real-time response capability. Meanwhile, the controller not only has low developing cost, but also is easy to upgrade maintenance and set the foundation for industrialization and standardization of industrial CT.