| The direct drive volume electro-hydraulic servo,which is called direct Drive Volume control DDV servo system,is a new control system which combines electronic technology with hydraulic technology.In this system,the valve components with high pollution,high failure rate and high cost are removed from the traditional hydraulic valve control system,such as throttle valve,relief valve and reversing valve,which provide power for the system by direct drive of two-way pump by AC servo motor.The system is controlled precisely by adjusting the steering and rotating speed of AC servo motor.The system has high flexibility,small volume and easy integration.Especially in the high-power working environment,its energy-saving effect is more and more remarkable,and it has been widely used in many fields at home and abroad.The new technology must go through a period of extension of technology and application field.Although the superiority of DDVC is beyond doubt,its application scope in China is not very wide.The main reason is that the application of direct-drive volume control electro-hydraulic servo system is not long enough in our country,and there are no cases to follow in many specific fields,so it is necessary to keep experimenting in order to achieve a breakthrough in application.This subject originates from the project of "20MN Pressure-Shear testing Machine".The energy consumed by the high-load material testing machine itself is very huge.Therefore,the DDVC system is studied and applied to the testing machine in order to save energy as much as possible.The following are the research directions of this topic:1)through reading a lot of related data,choosing control system for large load testing machine,need to consider from convenience,energy saving effect,cost,response speed and so on,by comparing the direct drive control system with the traditional valve control system,By checking many examples at home and abroad,it is determined that many advantages of direct-drive control system are in line with the requirements of the testing machine;2)the direct drive control system itself has strict requirements for motor and hydraulic pump.The core of the system is how to realize the accurate speed regulation of the motor and the dynamic stability of the executing unit(pump control cylinder).The mathematical models of AC servo motor and pump control cylinder are established,and the whole mathematical model of direct drive volume control electro-hydraulic servo system is obtained.The stability of the system is analyzed by matlab simulation;3)establish the experiment platform of direct drive control system,design electric and hydraulic separately,then select the hardware and design the software according to the condition of the laboratory;4)the experiment analysis of the direct drive control system is carried out,the PID controller is added,and the PID parameters are constantly adjusted in the process of the experiment to obtain the best response signal curve;5)the whole structure of 20MN compression shear testing machine is designed,and the strength of the model and the frequency range of allowable work are checked by finite element analysis and modal analysis.Then the hydraulic control part is designed,and the direct drive control system is applied to the testing machine,and its energy saving effect is proved by calculation.At the end of this paper,several hardware configuration schemes are put forward for reference. |
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