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This paper deals with dynamic analysis of a 5-DOF hybrid machine tool by using its scale model considering the geometrically distorted revolute joint. Geometric distortion of revolute joint can reduce the accuracy of similitude analysis by causing partial similitude problem. To solve this, scaling laws related to dynamic characteristics are derived, and those may not invariants in partial similitude problem are figured out. Then, the effects of revolute joint properties on dynamic characteristics are investigated. Based on this, the partial similitude problem is eliminated by relaxing scaling laws with little influence on the analysis. The scaling factors of dynamic characteristics are derived according to the reserved scaling laws. Finally, the predicted dynamic characteristics, including natural frequencies and mode shapes, of the full-size machine tool are obtained from its scale model.

A computer measurement and control system of test device for grain drying is designed by combining virtual instrument technology and computer measurement and control technology. Working done by hand or half hand system is solved by the automatic system. The hardware is designed with computer and ADAM module as its core, and the software is developed by Lab Windows/CVI. Digital incremental PID control algorithm is used in the process control. Anti-interference technology for hardware and software is applied. The result of experiment indicates that the temperature error was less than ±1°C", "the moisture error was less than ±2.17%and wind speed error was less than ±0.1m/s. The computer measurement and control system has a good performance and reaches the design and application requirements well.