Research And Development Of An Automatic Control System For A Lever Type Force Standard Machine Based On Virtual Instrument Technology

Force standard machines, essential equipments for the national department of metrology, play an indispensable role in the national economy, scientific measurement, and national defense building. With the rapid development of modern industry and scientific and technological progress by leaps and bounds, there is an increasing requirement for the accuracy, stability, efficiency, and intelligence of force standard machines. To address the low degree of automation, poor reliability, operational inconvenience and other limitations in traditional lever-type force standard machines, an automatic control system for them is introduced based on virtual instrument technology in this paper.Following are the thesis's main research work and achievements:1. According to the design principle of the virtual measurement and control system, an automatic control system for the level type force standard machine based on virtual instrument technology is introduced through analyzing the structural, functional and performance demands of the control system of force standard machine.2. A hardware platform is established for the control system of force standard machine. A method of two level (platform-level and task-level) multi-task scheduling strategy is proposed and implemented for the control system software platform through detailed analysis of the multi-tasking mechanisms in LabVIEW environment; and on this basis, the visual and vivid control system software is designed and developed.3. According to the long-term test practice on the level type force standard machine, a fault dictionary is proposed and implemented in the applications of accident warning and fault diagnosis for the control system, which effectively protects the reliability of the system.4. In order to improve the performance of force standard machine, a method is presented to enhance the sensitivity of the force standard machine by promoting the focus of lever; after discussing the error and its source of the lever type force standard machine, several corresponding counter-measures are presented to reduce the error of machine.Application results show that the control system can not only realize the automation of force measurement and data processing, reduce the labor intensity of operators, raise the efficiency of the verificational work, it can eliminate the human factors affecting the accuracy of the measurement and improve the reproducibility, accuracy and reliability of the equipment.