| The servo press cancels the flywheel mechanism used for energy storage by the traditional crank press.It adopts high-power servo motor as the power source,and has the advantages of adjustable velocity,controllable pressure,high motion precision,energy saving and environmental protection,etc.,which can meet flexible processing and high.It is widely used for process requirements such as strength material forming,complex part forming,composite forming,and high-precision forming.The multi-link mechanism is applied to servo presses with large pressure requirements due to its simple structure,easy manufacturing,and increased torque.It can be used for forming difficult-to-machine high-strength materials,but due to its material properties and manufacturing processes.Factors,there are often gaps in the joints,and the link mechanism will be deformed due to the tremendous pressure,which will adversely affect the precise tracking and control of the multi-link servo press slider trajectory.Therefore,from the perspective of slider trajectory tracking control,this paper conducts research on ulti-link working mechanism,servo motion control algorithm,error active compensation strategy and control system experimental platform development,and carries out related simulation and experimental verification.The main research contents of this paper are as follows:1.Introduced the research background and significance of the topic.From the development of the servo press,the common press drive mechanism,control system and control strategy,the research status of servo press at home and abroad is introduced;2.For a new multi-link working mechanism,kinematics and dynamics analysis,analysis of the motion relationship between the components and the force,and kinematics for the characteristics of the multi-link mechanism and processing conditions.And simulation of dynamics;3.The control strategy of the servo system is developed.The influence of the deformation of the rod under the working condition of the multi-link working mechanism on the motion accuracy is proposed.Based on the feedback of the force and displacement,the error compensation active control strategy is proposed.The offline experimental method is used to calculate the error.The equivalent stiffness of the multi-link mechanism,and introduces three classic servo system control algorithms;4.According to the actual needs of servo slider trajectory tracking control,the experimental platform of press servo system is built,and the experimental platform design is completed by virtual instrument technology.It mainly consists of the following two aspects:(1)Hardware:electrical cabinet design,motion control design,position and pressure detection and data acquisition modules.(2)Software:data acquisition program,signal output program,system initialization program and experimental platform control interface.5.According to the structural characteristics of the multi-link working mechanism,the ideal control model and contact force model of the mechanism are established.The control equation with single gap is derived and the response model of the motor is determined.By simullink simulation model,the control effects of different control algorithms on the trajectory of the multi-link servo press slider are analyzed and verified by experiments.It is found that the switching PID control can effectively reduce the slider trajectory control error.The model predictive feedforward active compensator is combined with the switching PID control algorithm.Three kinds of stamping process curves are used as input for the deep drawing experiment.The experimental results verify that the error active compensation control strategy can effectively improve the slider track control accuracy. |
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