Research On Multi-motor Drive System Of Production Line Of Continuous Vacuum Coating

The steel strip coated by vacuum coating system is excellent to resist wear, corrosion, scratch and excellent on insulation too. That strip can replace alloys or other expensive materials in many cases, which can easily reduce the cost of production and the pollution to environmental. The difficulty of strip continuous vacuum coating is how to ensure coat is uniform and achieve large-scale industrial product. Above process is deeply affected by the performance of multiple-drive in continuous vacuum coating production line. With the development of industry and technology, relatively independent of the speed and position controller has been unable to meet the coordinated operation of the transmission system, thus affecting the quality of the strip vacuum coating. So it has great significance to study the inverter control transmission system used advanced control theory and applied to the strip continuous vacuum coating production line.Firstly, this paper explains the structure and characteristics of the strip continuous vacuum coating production line, analyses the process of production line. From a conclusion that the tension of every process section on strip vacuum coating production line is coupled with the running speed of the motor, we explained the formation the strip tension and the difficulty of regulation and the necessity of controlling the tension and speed. From the analysis of the frequency control technology, the paper introduces the principle of frequency control and inverter selection method, then get the structure of the multi-frequency drive control system through study the composition of the multi-frequency transmission system.It is difficult to establish accurate mathematical model of the variable frequency drive system because it multivariable, nonlinear and strong coupling features. RBF neural network has the ability to approximate any nonlinear function, so use of RBF neural network can achieve adaptive adjustment of the control parameters of the PID controller, thus get the adaptive control system that tuning PID parameters based on RBF neural network. This paper designed a PID controller based on RBF neural network through study the multi-drive system based on the drive motor which used the three S roller tensioning device. The simulation results show that the speed of multiple-drive motor has no effect on tension if the tension is unchanged and the tension has no effect on the motor speed if the tension is unchanged, the result indicate that this system achieves a decoupling control of motor speed and tension. In addition, this system has a significantly response to motor speed and tension changes when we use the control method, which indicated this system has good dynamic performance and speed tracking ability. Compared with the traditional PID control, the proposed control method is more advanced and efficient. After researched characteristics of the strip continuous vacuum coating production line, we find an overall control scheme of the inverter drive control system. This scheme includes hardware design based on INDUSTRIAL COMPUTER610L industrial control computer and Siemens S7-300PLC used RBF neural network to tune PID parameters of multi-drive control system and software design about the rules, as well as the design process of multi-frequency drive control system.At last, we summarize main work of the whole thesis, and do a simple analysis about the other problems exist in multi-motor synchronous control system, as well as directions for future research are described.