All electric vertical injection molding machine in Japan started by the end of 2000, more than the Japanese production of 500t following vertical injection molding machine 90% are all electric vertical injection molding machine, however, Europe in this respect slow. Enterprises in Taiwan, Hongkong, and some use Japanese technology or developed in cooperation with Japan or all electric vertical injection molding machine itself are developed. All electric vertical injection molding machine will become the direction of technology of industry of vertical injection molding machine.

All electric vertical injection molding machine injection by so-called refers to the original hydraulic system to realize the holding pressure, back pressure, sol Kai Suomo and thimble to be controlled by motor to realize the high precision plastic products, to meet the growing needs of the market. In the industrial field, there are two most widely used types: permanent magnet motor (AC or DC brushless motor and AC induction motor), used in the field of vertical injection molding machine is a permanent magnet motor FANUC proposal, i.e. AC permanent magnet synchronous motor. This scheme has its performance advantage, but because of the manufacture and control technology of large power permanent magnet synchronous motor is not my master, and therefore expensive imports. Chinese manufacturers are many it as a technical reserve and technology in development, advertising, in difficult and import machine competition.

The world's first successful development of all electric vertical injection molding machine FANUC and compares the advantages and disadvantages of two kinds of motor, and the Japanese permanent magnet motor control technology in the world leading position in Japan, so FANUC is widely accepted. Permanent magnet motor some advantages compared with induction motor, FANUC sums up 4 points: first, good acceleration performance, fast response; the large range of speed regulation can be smoothly carried out; the braking performance is good; the induction motor power. In fact, the above conclusion is 20 years ago. Although He Yongci synchronous motor compared induction motor has its weakness, but in the past ten years, especially since the last century since the 90 generation of the new power electronic devices (such as IGBT, IGCT etc.) development and performance improvement, the development of computer technology (CPU from 16 bits to 32 bits, DSP chip with high performance and new appearance) control theory application (such as: core oriented vector control and direct torque control) and other reasons, has greatly promoted the development of variable frequency induction motor control technology, the frequency conversion control technology in the control range, the control precision and dynamic response, power factor number, and the operation is convenient very significantly improved. Therefore, we bold ideas: the use of motor vector control technology and special tailor-made induction, entirely possible to develop the performance price ratio of the whole electric vertical injection molding machine of excellence.

1 the principle of control system

1.1 vertical injection molding machine and its control system

The basic structure of vertical injection molding machine is composed of three parts: the injection device, the mold opening device and the next frame part. Injection device for the completion of melt metering and injection pressure maintaining function; ejector function mold opening closing device and mold; under the frame supporting the role of parts of machine, electric and control device is installed in them.

Through the melt process, plastic volume rapid, accurate measurement of plastic products in need; in the filling process, effective, fast, accurate measurement of the plastic into the mold good will have locking, and the implementation of the appropriate pressure and cooling; finally open die, ejecting the product, make a complete cycle plastic products.

The upper controller has three main functions: setting control parameters and target; display control results; machine coordination in every link of the action sequence.

The main function of motion controller is in coordination between host controller, to complete the process control, such as control of pressure, position and speed, and the control results and the relevant state transfer to the host controller. That is to realize the melt injection motor, motor, motor lock mode and the ejection of motor control.

The control process can be described as: from the upper controller instruction to achieve what control (such as injection velocity or pressure control), the motion controllers will be received in accordance with the instructions and actual situation, give control adjustment signal to the frequency converter; inverter rotary drive motor, permanent magnet motor and ball screw are connected by a belt, converting circular motion into linear the movement, so as to realize the control of speed, pressure or position.

The realization of the 1.2 control system

The upper controller using a touch screen, so that the set of data the operation more convenient, better control results show.

Motion controller embedded real-time operating system (RTOS), used at present in the field of industrial control applications most real-time _iTRON OS wide, high efficiency, good reliability, easy programming, strong transplantation. Based on the development of OS, the adaptive control algorithm and software control object characteristics.

Inverters with vector control. According to the inherent characteristics of induction motor, we put forward pertinence control algorithm in frequency converter, to improve the performance of control system.

Because the use of real-time operating system, so the system control software, so there is the concept of "task".

The main control algorithms, including speed control, position and pressure, are executed in interrupt service subroutine. I/O read and write, and host controller communication task, to form by the operating system (RTOS) to arrange the execution. The connection between each task and task state transitions by MailBox communication to establish and implement.