Research On On-Line Closed-Loop Control Of Profile Rolling Accuracy

At present,it is difficult to control the forming accuracy in the roll bending process of aluminum alloy profiles,which is primarily due to two reasons,First,the roll-bending process of aluminum alloy profiles is a process of locally constrained elastic-plastic deformation,which is prone to springback;Second,the roll-bending process is a process of dynamically changing the position of the profile,and the roll-bending forming size is the size of the profile after bending and rebounding,which is not easy to measure accurately online.Therefore,the roll bending process is mostly open-loop control,and it is difficult to control the forming accuracy.In order to solve the problem of online roll bending accuracy control of profiles,This paper proposes a feed-forward closed-loop control method for roll-bending based on online dimension detection and machine learning,the online closed-loop precision control of the dimensions of rolled-bending parts is realized by online dimension detection and feed-forward prediction based on bending error data.The main research work in this paper is as follows:(1)The roll-bending drive mechanism is designed,based on the working principle of the roll-bending drive mechanism,the dynamic model of the roll-bending drive mechanism and the PID control model of the position loop are established,and the PID parameters are set,which provides the basis for the roll-bending closed-loop control.(2)A feedforward predictive control strategy based on support vector machine is proposed,and a forming curvature prediction model and three error compensation methods based on mold-mounting error compensation,curvature error compensation and radius error compensation are established based on support vector machine,the simulation of the error-compensated profile variable-curvature roll-bending predictive control model provides a basis for the selection of the roll-bending error compensation method.(3)The off-line predictive control experiment of roll bending,the simulation experiment of constant curvature based on the compensation of mold fitting error,curvature error compensation and radius error compensation,and the pre-bending experiment of variable curvature based on curvature error compensation are carried out.Based on the variable-curvature pre-bending experimental data,the variable-curvature roll-bending experiment based on off-line error compensation prediction is realized.(4)The general framework of the roll-bending control system was constructed,the construction of the online predictive control rolling-bending test bench was completed,and the variable-curvature online predictive-control roll-bending experiment was carried out to verify the feasibility of the online predictive control of the profile rolling accuracy.