Design And Research Of The Hydraulic Proportional Control System Of A Tube Straightener

Tube straightener as one kind of finishing equipments is often used in the last part of the tube production to eliminate the tube’s bending and distortion caused by residual stress, the change of temperature and the inner stress. As one finishing equipment, it plays the dominant role of determining the tubes’quality. And the precision of the roll-gap is the key element. This paper is written based on a Tantalum-Niobium tube straightener, which is controlled by the PLC and uses touch panel as the human machine interface. In this paper, the design of the hydraulic system is carried out and tested through simulation using DSHplus and Simulink. The programming of PLC and touch panel is also introduced. This paper is organized as follows:Relevant background information is presented in Chapter1. This chapter includes a literature review on the development of straigheners and requires of high-precision straightening. A review on the development of hydraulic control system is then presented. A summary of the advantages and disadvantages of some advanced control strategies then follows.Chapter2describes the demands for the proportional-hydraulic system set by the host machine. Then the design and calculation of the hydraulic system is presented. The design method of manifold block using three dimensional software (Solidworks) is introduced. The application method of displacement sensor and proportional valve amplifier is also described.Modeling and simulation using DSHplus is carried out to check the design in Chapter3. The same model is also built in Simulink based on differential equations rather than traditional transfer function to compare the difference between the two softwares.Chapter4presents the programming of PLC and touch panel. Additionally, the implementation method of dead-time compensation for the proportional valve is introduced. It ends up with the experiment test result of the cylinder.Chapter5introduces the application of tuning PID parameters using relay feedback method based on amplitude and phase margin. The co-simulation between Simulink and DSHplus testes the effectiveness of this algorithm. The final remarks and conclusions are included in Chapter6. In addition, the chapter ends up with a brief list of possible extensions of this research and future work.