Abstract: This paper introduces a microcomputer-based automatic testing system for mechanical dynamic parameters based on virtual instruments, and elaborates on the system's working principle, hardware structure, and software programming. The system integrates virtual instrument technology and modern measurement and control technology to achieve online monitoring and management of mechanical dynamic parameters. Practice shows that the system performs well. Keywords: Virtual instrument, mechanical dynamic parameters, automatic measuring system [b][align=center]THE DESIGN OF MECAHNICAL DYNAMICAL PARAMETERS AUTOTEST SYSTEM BASED ON VIRTUAL INSTRUMENT Zhu Wenxing, Yu Ruiling, Jia Lei[/align][/b] Abstract: This paper introduces a computer-based automatic measuring system for machinery dynamic parameters. It explains the system's principle, hardware structure, and software design. Online monitoring and management of mechanical parameters are achieved through virtual instrument technology and modern measurement and control technology. Practice has shown that the system performs excellently. Key word: virtual instrument, machinery dynamic parameters, automatic measuring system 1 Introduction Virtual instrument technology is a computer-based measurement and control solution. Unlike intelligent instruments that integrate computer technology into a computer, it flexibly combines various computer platforms, measurement and control instruments, and other hardware, software, and accessories according to the user's needs to form a specific intelligent measurement and control system, realizing specific functions for the user. The foundation of a virtual measurement and control system is a computer system and related measurement and control hardware. Laboratory staff who understand and master virtual instrument technology can become users, maintainers, and updaters of this measurement and control system. This system is a complete microcomputer-based automatic testing system for mechanical parameters, designed to update experimental teaching methods in mechanical design courses, based on a standard V-belt drive test bench. V-belt drives are important transmission components widely used in machinery. Traditionally, the measurement of their power parameters often employs a "sensor + secondary instrument" method, typically only providing measurement and display functions. The poor dynamic characteristics of secondary instruments often affect measurement accuracy. Therefore, we developed a microcomputer-based automatic testing system. This system integrates measurement, data processing, storage, and analysis functions, enabling the detection of various mechanical power parameters during transmission and quantitative analysis of their performance. 2. Working Principle of the Experimental Bench The experimental bench has two DC motors fixed on two supports. The speed-regulating motor is the driving wheel, and the generator is the driven wheel. Energy is transferred between them via a belt. The generator load is an adjustable resistance box; changing the resistance value changes the load. The mechanical dynamic parameters to be measured are the rotational speeds n1 and n2 of the two motors under different loads, the belt slip ratio ε, and the transmission efficiency η. 2.1 Rotational Speed ​​Measurement: Geared discs are installed on the outer axles of the driving and driven wheels, with the gear holes evenly spaced across the circumference. Magnetoelectric sensors are installed below the geared discs. When the motors rotate, the magnetoelectric sensors output a periodic signal. By measuring this calibrated periodic signal, the rotational speeds of the driving and driven wheels can be obtained. For details, please click: Development of an Automatic Testing System for Mechanical Dynamic Parameters Based on Virtual Instruments