| 摘要 |
<p>With regard to pressure control of an electric injection molding machine, there has been a demand for a method of detecting injection pressure with high precision and extremely small time lag without the need of an expensive pressure detection sensor that requires complicated installation work, a complex mechanical structure, or such manual operations as noise suppression measures or zero-point adjustment. The device and the method employ a high gain observer that incorporates a discrete arithmetic expression derived by using an equation of state for expressing a numerical formula of an injection/pressure-keeping mechanism of the electric injection molding machine. The high gain observer receives input signals comprising a screw position signal in addition to a motor current command or actual motor current, and outputs an estimated value of injection pressure, which is one of status variables of the aforementioned equation of state. The high gain observer outputs an estimated value of injection pressure with high precision and extremely small time lag without the need of a pressure detection sensor. Therefore, an estimated value of injection pressure output from the high gain observer can be used as a feedback signal of a detected value of injection pressure for injection pressure control.</p> |
