The coiling temperature of the hot strip rolling process plays an important role in strip quality control. The newly-built laminar flow cooling control system was independently developed by Baosteel. L2 conducts total...The coiling temperature of the hot strip rolling process plays an important role in strip quality control. The newly-built laminar flow cooling control system was independently developed by Baosteel. L2 conducts totally dynamic control （L1 only executes the result from L2, and does not conduct any dynamic control ）. The system has many advantages, such as quick real-time control, accurate model calculation, quick response after self-adaptation, etc. Compared with the 2050 mm hot strip rolling line,the new system can satisfy the strict cooling requirements of high strength steel, silicon steel and heavy plates because of its newly-developed technologies of cooling rate control, strip cooling by sections and proportion-integral-differential coefficient （PID） feedback fuzzy control.展开更多
Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so...Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is lagged.Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms.In this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed.On this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward.And a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time.The two valves are arranged in parallel to control the cylinder jointly.Furthermore,the model of flow compensation is derived,by which the product of the amplitude and width of the valve’s pulse command signal can be calculated.And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations.Using the proposed scheme,simulations and experiments at different positions with different force changes are conducted.The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time.That is,system dynamic load stiffness is evidently raised.This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.展开更多
文摘The coiling temperature of the hot strip rolling process plays an important role in strip quality control. The newly-built laminar flow cooling control system was independently developed by Baosteel. L2 conducts totally dynamic control （L1 only executes the result from L2, and does not conduct any dynamic control ）. The system has many advantages, such as quick real-time control, accurate model calculation, quick response after self-adaptation, etc. Compared with the 2050 mm hot strip rolling line,the new system can satisfy the strict cooling requirements of high strength steel, silicon steel and heavy plates because of its newly-developed technologies of cooling rate control, strip cooling by sections and proportion-integral-differential coefficient （PID） feedback fuzzy control.
基金supported by National Natural Science Foundation of China(Grant No.51075291)Shanxi Scholarship Council of China(Grant No.2012-076)
文摘Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is lagged.Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms.In this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed.On this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward.And a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time.The two valves are arranged in parallel to control the cylinder jointly.Furthermore,the model of flow compensation is derived,by which the product of the amplitude and width of the valve’s pulse command signal can be calculated.And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations.Using the proposed scheme,simulations and experiments at different positions with different force changes are conducted.The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time.That is,system dynamic load stiffness is evidently raised.This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.
