| Press machine is one kind of high-danger machines in industrial machines.Lots of accidents happened due to improper operation and lack of safety on the press.Therefore technical standards are made internationally and domestically to illustrate safety requirements of the press.On the other side,the improvement of the servo control technology impels the movement of the mechanical press from traditional fly wheel driven towards servo driven.The main research of this thesis is to make risk assessment on a mechanical servo press and decrease the possibility of dangerous accidents by increasing the reliability on the electrical control system of the machine.In order to realize this,the electrical control system of the mechanical servo press is designed associating with safety related control system standards.Finally the reliability of the machine is validated.The thesis contains the following parts:1.Make risk assessment on a 5-Ton mechanical servo press and list all hazards.Determine all safety functions on the electrical control system and performance level for each safety function.2.Discuss the affect to reliability by different system structure.Provide hardware structure of the control system for the 5-Ton servo press.Provide methods to implement safety stop function for nonsafety servo controllers.3.Design software related safety functions based on the platform conforming to IEC 61131-3.Provide reliable slide position monitoring methods in safety PLC.4.Implement Safe Stop 1,Safe Operation Stop,Safe Limit Speed,Safe Break Control and Safe Break Test by configuring safety servo controller.5.Perform fault injection test.Validate performance levels of designed control system by calculating safety related parameters.The result shows that comparing with traditional control system,the methods described in the thesis can largely increase the reliability of the mechanical servo press,as well as conforming to the related international and domestic standards. |
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