Control Strategy Research On Independent Spool Slewing Valve In The Condition Of Large Inertia

Rotary control valve,which is one of the main components of engineering machinery rotary system,is used to control the relative rotary movement between upper part and lower part,with the cooperation with lifting and boom,sending the weights to the destination through slewing.Traditional slewing valve is mostly using bypass throttle orifice circuits,but its starting and braking time is long when in rapid acceleration and deceleration with big vibration and impact.Although most systems have added buffer valve now,if the buffer function is too strong,it will reduce the loading ability and lead to lag,let alone in big inertia condition.These defects will speed up the destruction of other parts,reduce working life,and even cause safety accidents.Separate meter-in and separate meter-out technology applying two independent spools to control the inlet and outlet can control the flow and pressure independently.It has increased the control degree of freedom and can achieve better performance comparing with the traditional reversing valve.So it’s necessary to apply this technology to slewing system in big inertia condition and have research on the control strategy,acting out its advantages.This paper set MSC slewing valve as research object and analyze the work principle of the valve.Analyze and classify the main load working conditions of crane slewing system.According to different conditions,make the corresponding flow control and pressure control strategy through setting different parameters of PID control.Optimize the parameters constantly by the simulation model constructed in AMESim and Simulink,achieving optimal performance of various conditions.After the programming of data reading,load identifying,flow control and pressure control in BODAS controller,complete the bench test of steady-state characteristics,dynamic characteristics and the load fluctuation characteristics of the MSC valve.Compared with traditional reversing valve,independent spool slewing valve has superiorities like better linearity and following property of flow,smaller control dead zone,stable starting and braking and lower pressure shock.The research content of this paper is divided into 6 chapters,and the contents of each chapter are briefly described as follows.In chapter 1,first introduce the concept and development of rotary valve.Then introduce the principle,control strategy and current development situation of separate meter-in and separate meter-out technology.Finally puts forward the significance,objectives,main contents,research route and difficulties of this research.In chapter 2,mainly introduce the working principle of MSC valve.Preliminary bench experiment is done to guide the construction of simulation model in AMESim which is proved to be correct by comparing the simulated curve and bench experiment curve.In chapter 3,analyze the main load conditions of slewing system of truck crane and introduce the concept and method of load identification.According to different load conditions,have research on the control strategy of independent spool slewing valve and verify its feasibility by simulation in AMESim and Simulink.In chapter 4,the basic principle,distribution of stitching and programming of Bosch Rexroth BOD AS RC6-9 controller which is used to control the MSC valve,is introduced.In chapter 5,introduce the composition and principle of test rig,then the bench test of MSC independent spool slewing valve with control strategy is done with testing of steady,dynamic and the load fluctuation characteristics under four kinds of working conditions,as a result,verifying the performance advantages of MSC valve.In chapter 6,the main research contents and achievements of this thesis are summarized,and put forward some suggestions on the future further research.