JP3177752B2 - Control device for glass lens press molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for controlling a pressurizing actuator of a glass lens press forming machine for obtaining a glass lens by press-forming a preform using a pressurizing actuator.

[0002]

2. Description of the Related Art Optoelectronic devices using optical components, such as video cameras and laser printers, are being marketed one after another today. However, these devices are becoming more sophisticated and smaller, lighter and less expensive. , An aspheric glass lens is indispensable. As is well known, the step of forming such an aspherical glass lens by pressing includes the following steps.

[0003] First, a preform (glass material) of an aspherical glass lens to be molded is supplied into a mold (press mold) precisely processed into an aspherical shape. Here, the mold is made of ceramics, and has a cylindrical body mold, a lower mold fixed in the body mold, and an upper mold slidably arranged in the body mold opposite to the lower mold. And the above-mentioned aspherical shape is formed on the opposing surfaces of the lower die and the upper die. That is, the preform is sandwiched between the lower mold and the upper mold.

[0004] In this state, by heating the body mold,
The preform is raised to a temperature at which it can be molded. Then, the upper mold is pressed into the body mold by the pressing means, whereby the aspherical shape of the mold is transferred to the preform. Thereafter, the preform on which the aspherical shape has been transferred is cooled to a region where it does not change its shape. Then, the cooled and fixed aspherical glass lens is removed from the mold.

By repeating the above steps, 1
Aspherical glass lenses are formed individually.

By the way, since the sizes of the preforms are different one by one, if the upper mold is pressed under the same conditions, cracks may occur in the molded aspherical glass lens,
The accuracy of the aspherical glass lens was sometimes reduced.

In order to solve this problem, the present inventors have already filed a Japanese Patent Application No. 3-273165 on September 25, 1991 under the title of "Glass Lens Press Forming Machine". . In the glass lens press molding machine of this application, as a pressing means for pressing the upper mold into the body mold,
An electro-pneumatic servo actuator with a built-in spool is used. By employing such an electro-pneumatic servo actuator, it is possible to efficiently form an aspherical glass lens without causing cracks or a decrease in accuracy, regardless of variations in the size of the preform. Was.

Referring to FIG. 2, the construction of the glass lens press molding machine of the present invention will be described. The glass lens press machine has an electro-pneumatic servo actuator 100. Electric-pneumatic servo actuator 1
Reference numeral 00 denotes a reciprocating pneumatic cylinder including a cylinder body 102 and a piston 104 disposed in the cylinder body 102. The piston 104 causes the interior of the cylinder body 102 to have a first airtight chamber 138 and a second airtight cylinder. It is separated from the closed room 140. A spool 112 is incorporated inside the piston 104. This spool 11
2 is moved along the moving direction of the piston 104 by a stepping motor (electric motor) 128 attached to a reciprocating pneumatic cylinder. The first and second airtight chambers 13 are formed by the spool 112 and the piston 104.
A spool valve for controlling the air pressure balance of 8, 140 is constituted.

In the electro-pneumatic servo actuator 100 having such a structure, when the stepping motor 128 is driven as described later to move the spool 112,
The first and second hermetic chambers 138 and 140 are operated by the operation of the spool valve.
The air pressure balance changes. In response to this change, the piston 104 follows the movement of the spool 112 so as to eliminate the positional deviation between the spool 112 and the piston 104. This electro-pneumatic servo actuator 100
Is a drive rod 10 extending downward from the piston 104.
The drive rod 108 is arranged above the press die 20. For the detailed structure of the electric-pneumatic servo actuator 100, refer to the above-mentioned application.

[0010] As described above, the press mold 20 is used for the body mold 2.
And an upper mold 3 and a lower mold 4. Drive the upper die 3 to the drive rod 10
By pressing the preform 1 at 8, the preform 1 supplied into the press die 20 can be formed.

A position detector 30 and a load cell (force detector) 40 are attached to a drive rod 108 of the electro-pneumatic servo actuator 100. The position detector 30 detects the position of the drive rod 108 and outputs a position detection signal P1. The load cell 40 includes the drive rod 1
08 to detect a load in the axial direction acting on the power detection signal P2.
Is output. The position detection signal P1 and the force detection signal P2 are supplied to the control device 50 '. The control device 50 'controls the stepping motor 128 of the electro-pneumatic servo actuator 100 based on the position detection signal P1 and the force detection signal P2.
Is calculated. The operation amount P5 is amplified by the motor amplifier 60 and supplied to the stepping motor 128.

In general, the control device has a command generation unit for generating a command value, and a calculation unit for calculating an operation amount such that a detection signal corresponding to the command value matches the command value. The calculation unit includes a subtractor that calculates a deviation between the command value and the detection signal and outputs an operation signal, and an adjuster that converts the operation signal into an operation amount. The adjuster is also called a compensator and has a control parameter (control gain).

In the conventional control device 50 ', the control parameters of the controller are fixed as described later.

Here, as a control method of press molding of a glass lens, there are a method of controlling a pressing position and a method of controlling a pressing force. The latter method has the advantage that variations in the size of the preform can be tolerated.

FIG. 3 shows a conventional control device 50 'when a force control system based on PI control for feeding back a force detection signal P2 from the load cell 40 is formed.

The conventional control device 50 'includes a force command generator 5
1 and a force control system calculation unit 52 '. The force command generator 51 generates a force command value P3 of the pressing force during lens molding. The force control system calculation unit 52 ′ calculates the PI of the operation signal P4 representing the deviation between the force command value P3 and the force detection signal P2.
Executes (proportional + integral) calculation and returns to stepping motor 1
A manipulated variable P5 of 28 is obtained. More specifically, the force control system operation unit 52 'includes a subtractor 52-1 and a PI adjuster 52'-2.
And The subtractor 52-1 subtracts the force detection signal P2 from the force command value P3, and outputs an operation signal P4 indicating the difference. Fixed control parameters are set in the PI controller 52'-2. The PI adjuster 52'-2 has a proportional gain K1 and an integral term gain K2 as control parameters. That is, the transfer function G of the PI controller 52'-2
(S) is represented by Equation 1 below.

[0017]

(Equation 1)

The PI adjuster 52'-2 executes a PI operation on the operation signal P4, and
The operation amount P5 is output.

As described above, in the conventional control device 50 ', the control parameters of the compensator are fixed.

[0020]

During press molding of glass lenses, the load resistance varies substantially with the deformation of the preform. The conventional control device 50 'sets control parameters so as to be stable in a limited area. Therefore, in the conventional control device 50 ', an unstable area is generated depending on the state of deformation of the preform. As a result, there is a problem that the glass lens press molding machine using the conventional control device 50 'cannot perform stable molding.

Accordingly, an object of the present invention is to provide a control device which enables a glass lens press molding machine to always perform stable glass lens press molding.

[0022]

According to the present invention, a control apparatus for a glass lens press forming machine according to the present invention comprises a preform press-molded by using a pressurizing actuator to obtain a glass lens, and the speed is controlled in accordance with the deformation amount of the preform. A control device for controlling a pressurizing actuator of a glass lens press forming machine in which a proportional forming load is generated. The control unit generates a command value, detects a load condition of the pressurizing actuator, and outputs a detection signal. A calculating unit that calculates an operation amount of the pressurizing actuator using a command value and a detection signal in accordance with a variable control parameter; and estimating a resistance of a molding load from the detection signal and the operation amount. And a parameter adjusting unit that adjusts a control parameter according to the resistance of the formed molding load.

In the control apparatus for a glass lens press molding machine, the command generation section is a force command generation section for generating a force command value of a pressing force at the time of lens forming, and the detector detects the position of the drive rod of the pressurizing actuator. It comprises a position detector that detects and outputs a position detection signal, and a force detector that detects an axial load acting on the drive rod and outputs a force detection signal. A force control system operation unit that obtains an operation amount by performing a PI (proportional + integral) operation on an operation signal representing a deviation from a signal, and has a proportional gain and an integral term gain as control parameters. ,
The parameter adjuster estimates the resistance of the forming load based on the operation amount, the position detection signal, and the force detection signal, and adjusts the proportional gain and the integral term gain appropriately according to the estimated forming load resistance. I do.

It is preferable that the parameter adjusting section obtains in advance the relationship between the forming load resistance and the control parameter for stabilizing the control system, and adjusts the control parameter using this relationship.

[0025]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a control device 50 of a glass lens press molding machine according to an embodiment of the present invention. The illustrated control device 50 receives the position detection signal P1 and the force detection signal P2 from the position detector 30 and the load cell 40, respectively, and based on the position detection signal P1 and the force detection signal P2,
The operation amount P5 of the stepping motor 128 of the air servo actuator 100 is calculated. The operation amount P5 is amplified by the motor amplifier 60 and supplied to the stepping motor 128.

The control device 50 also receives a force detection signal P2 from the load cell 40 similarly to the above-described conventional control device 50 '.
To form a force control system based on PI control that feeds back. However, in the control device 50, the conventional control device 50
Unlike ', the control parameters of the regulator are variable, as described below. That is, the control device 50 adjusts the control parameters according to the change in the load resistance. Thus, stable press molding can be performed on the glass lens press molding machine.

The control device 50 has a force command generator 51, a force control system calculator 52, and a parameter adjuster 53. The force command generator 51 generates a force command value P3 of the pressing force during lens molding.

The force control system computing section 52 responds to an operation signal P4 representing a deviation between the force command value P3 and the force detection signal P2 by a P
An I (proportional + integral) operation is executed to obtain an operation amount P5 of the stepping motor 128. More specifically, the force control system calculation unit 52 includes a subtractor 52-1 and a PI adjuster 52-2. The subtractor 52-1 subtracts the force detection signal P2 from the force command value P3, and outputs an operation signal P4 indicating the difference. Variable control parameters are set in the PI controller 52-2. The PI adjuster 52-2 has a proportional gain K1 and an integral term gain K2 as variable control parameters. The PI adjuster 52-2 performs a PI operation on the operation signal P4, and outputs an operation amount P5 of the stepping motor 128.

The parameter detector 53 includes a position detector 3
0, the load cell 40 and the PI adjuster 52-2 supply the position detection signal P1, the force detection signal P2, and the operation amount P5, respectively. The parameter adjustment unit 53 estimates a load resistance based on the operation amount P5, the position detection signal P1, and the force detection signal P2, and sends an adjustment signal P6 corresponding to the estimated load resistance to the PI adjuster 52-2. And P
Proportional gain K which is a control parameter of I adjuster 52-2
1 and the integral term gain K2 are adjusted appropriately.

Here, there are various methods for adjusting the control parameters. In the present embodiment, the parameter adjustment unit 53
Is determined in advance the relationship between the molding load resistance and the control parameter for the control system to be stable, and using this relationship,
The proportional gain K1 and the integral term gain K2 are adjusted.

Incidentally, such a method of automatically adjusting the control parameters is well known as auto tuning in the field of control technology. Therefore, it is a matter of course that the control parameters may be automatically adjusted using a known auto-tuning. For example, an internal virtual model can be used.

In any case, the manipulated variable P5 calculated by the control device 50 in this way is supplied to the motor amplifier 60, and further supplied from the motor amplifier 60 to the stepping motor 128 as a drive signal. 2) is driven.

In the above embodiment, an example is shown in which the pressurizing actuator is formed by an electric-pneumatic servo actuator. However, even when the pressurizing actuator is formed by an electric servomotor or the like, the control device of the present invention is not limited to the above. Be adaptable.

[0035]

As described above, according to the present invention, the operation amount of the pressurizing actuator is compensated by using a control parameter appropriately adjusted according to the change of the load resistance during the press forming of the glass lens. Thus, there is an effect that a stable press molding of a glass lens can be always performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control device of a glass lens press molding machine according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a glass lens press forming machine including a conventional control device.

FIG. 3 is a block diagram showing the conventional control device shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 30 position detector 40 load cell (force detector) 50 control device 51 force command generator 52 force control system calculator 52-1 subtractor 52-2 PI controller 53 parameter adjuster 60 motor amplifier 128 stepping motor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 11/16

Claims (3)

(57) [Claims] 1. A glass lens press-molding machine in which a preform is press-molded using a pressure actuator to obtain a glass lens, and a molding load proportional to a speed is generated in accordance with a deformation amount of the preform. In a control device for controlling an actuator, a command generation unit for generating a command value; a detector for detecting a load condition of the pressurizing actuator and outputting a detection signal; and a command value according to a variable control parameter. A computing unit that computes an operation amount of the pressurizing actuator using the detection signal and the detection signal, and estimates a resistance of the molding load from the detection signal and the operation amount, and according to the estimated resistance of the molding load. And a parameter adjusting unit for adjusting the control parameters. 2. The command generating section is a force command generating section for generating a force command value of a pressing force at the time of forming a lens. The detector detects a position of a drive rod of the pressurizing actuator to detect a position. A position detector that outputs a detection signal; and a force detector that detects an axial load acting on the drive rod and outputs a force detection signal, wherein the arithmetic unit includes the force command value and the force detection. A force control system operation unit that obtains the operation amount by performing PI (proportional + integral) operation on an operation signal representing a deviation from the signal, and has a proportional gain and an integral term gain as the control parameters. The parameter adjustment unit estimates the resistance of the molding load based on the operation amount, the position detection signal, and the force detection signal, and, in accordance with the estimated molding load resistance, the proportional gain and the integration term. Gain and The control apparatus for a glass lens press forming machine according to claim 1, wherein the control is performed so as to be appropriate. 3. The parameter adjustment section determines a relationship between the molding load resistance and the control parameter for stabilizing a control system in advance, and adjusts the control parameter using the relationship. The control device for a glass lens press molding machine according to claim 1, wherein: