JP2010003133A - Temperature control method and temperature control device - Google Patents

Abstract

A temperature control device and a temperature control method are provided that are suitable for preventing an excessive temperature rise of a heater that heats the object to be heated in contact with the object to be repeatedly supplied.
A temperature of a heater that heats an object to be heated is defined as a control amount PV, and an operation amount MV for driving the heater is obtained in accordance with the control amount PV to control driving of the heater. When the heat treatment of the object to be heated is started, the lowest drop value of the control amount PV is detected, and the upper limit value OH for the operation amount MV is set according to the lowest drop value of the control amount PV.
[Selection] Figure 3

Description

  The present invention relates to a temperature control method and a temperature control apparatus suitable for preventing an excessive temperature rise of a heater that sandwiches and heats an object to be heated that is repeatedly supplied.

  In a heating apparatus such as a tape bonder in a semiconductor manufacturing apparatus, the object to be heated 1 is sandwiched between a pair of upper and lower heaters 2 and 3 as shown in FIGS. In particular, the heaters 2 and 3 are maintained at a predetermined high-temperature state in order to increase the processing efficiency when sandwiching and heating a plurality of heated objects 1 to be repeatedly supplied one after another. Is called. However, in the case where welding or the like occurs due to the heating of the article 1 to be heated, it is necessary not to heat the article 1 to be heated to an unnecessarily high temperature. Therefore, it is important to control the heaters 2 and 3 to a necessary and sufficient appropriate temperature.

  By the way, for example, when the temperature of the upper heater 2 is controlled to 200 ° C. and the temperature of the lower heater 3 is controlled to 100 ° C., when the object to be heated 1 supplied at room temperature (for example, 25 ° C.) is sandwiched, As shown in FIG. 9B, the heated object 1 is rapidly heated by the movement of heat due to the contact between the heaters 2 and 3 and the heated object 1, while the temperature of the heaters 2 and 3 is as shown in FIG. Suddenly drops. Then, for example, a PID control operation with respect to the temperature of the heaters 2 and 3 works to recover the decrease in the temperature. In general, however, it cannot be denied that overshoot occurs due to the control characteristics. In other words, the temperature control of the heaters 2 and 3 by PID control generally emphasizes responsiveness (high-speed response) in order to supply heat from the heaters 2 and 3 to the heated object 1 at high speed and sufficiently. Then, the control parameter (PID parameter) is set. For this reason, when the abrupt temperature drop described above occurs, heater temperature overshoot is likely to occur due to the control operation characteristics.

  The temperatures of the heaters 2 and 3 finally return to the predetermined set temperature (control temperature) described above by the recovery operation after the overshoot described above. However, in general, heat tends to be accumulated in the lower heater 3 due to a difference in temperature between the heaters 2 and 3, a difference from the ambient temperature, and a structural problem of the apparatus. Therefore, it tends to take time for the temperature of the lower heater 3 to return to the original set temperature.

  Further, in such an apparatus, when the next object to be heated 1 is supplied before the temperature of the heaters 2 and 3 returns to the original set temperature, due to the accumulation of heat described above, FIG. As shown in FIG. 3, the temperature of the heaters 2 and 3 gradually rises, and it cannot be denied that a so-called overheating state occurs. In other words, even if the temperature of the heaters 2 and 3 is controlled by PID, if the next disturbance is given before the temperature stabilizes by the PID control following the temperature change caused by the disturbance, the control response will be tracked. This causes a problem that the temperature of the heaters 2 and 3 gradually increases.

Then, when the object to be heated 1 is sandwiched between the heaters 2 and 3, more heat than that necessary for the heat treatment of the object to be heated 1 is supplied to the object to be heated 1, and the object to be heated 1 is damaged. Cause. For such repeated disturbance factors, it has been proposed that the control target temperature is changed in accordance with the temperature change caused by the disturbance, thereby suppressing the above-described overshoot (see, for example, Patent Document 1).
JP 2002-297245 A

  However, the increase in the heater temperature due to the above-described overshoot is due to the accumulation of heat in the heaters 2 and 3 and is a factor that impairs the reproducibility of the recovery operation after overshoot by PID control. Therefore, in the overshoot suppression method disclosed in Patent Document 1, the suppression effect itself gradually decreases, and as a result, overheating of the heaters 2 and 3 cannot be prevented. There is.

  In this regard, a countermeasure may be considered in which the lower heater 3 that causes heat accumulation is once completely turned off. However, for example, if the supply of the heated object 1 is delayed and it takes time until the heated object 1 is sandwiched by the heaters 2 and 3, the temperature of the lower heater 3 is lowered more than necessary during that time. A malfunction occurs. Therefore, it is necessary to continuously control the temperature without turning off the lower heater 3.

The present invention has been made in consideration of such circumstances, and its purpose is to provide a temperature suitable for preventing an excessive rise in temperature of a heater that heats the object to be heated in contact with the object to be repeatedly supplied. A control device and a temperature control method are provided.
In other words, the present invention controls the temperature of a heater with a characteristic that emphasizes quick response, even when a disturbance is repeatedly applied with a short period that impairs the reproducibility of the recovery operation after overshoot. It is an object of the present invention to provide a temperature control device and a temperature control method capable of effectively suppressing an unnecessarily high temperature rise of the heater while continuing the above.

In order to achieve the above-described object, the temperature control method according to the present invention uses the temperature of the heater that heats the object to be heated as a control amount PV, and obtains an operation amount MV for driving the heater according to the control amount PV. When controlling the heater drive [Prerequisites]
As described in claim 1, when the heating process of the object to be heated by the heater is started, the lowest drop value of the control amount PV is detected, and the operation amount is determined according to the lowest drop value of the control amount PV. It is characterized by setting an upper limit value for MV.

  According to the temperature control method of the present invention, when the heating process of the object to be heated by the heater is started as described in claim 2, the time during which the manipulated variable MV is saturated is detected, and this saturation time The upper limit value for the manipulated variable MV is set according to the above. Or when the heat processing of the said to-be-heated material by the said heater is started as described in Claim 3, the said operation amount MV at the time of the heat processing start is detected, According to the operation amount MV at the time of this heat processing start Thus, an upper limit value for the manipulated variable MV is set.

  Incidentally, the heater is made of, for example, a member that contacts the object to be heated and heats the object to be heated. Regarding the start of the heating process of the object to be heated by the heater, for example, between the heater and the object to be heated. The detection may be performed at the time of contact or at the time of contact operation. It is also possible to monitor the change amount ΔPV of the control amount PV and detect the time when the change amount ΔPV exceeds a predetermined threshold as the start of the heat treatment.

In order to achieve the above-described object, a temperature control device according to the present invention includes a heater for heating an object to be heated, a temperature sensor for detecting the temperature of the heater, and driving the heater based on the output of the temperature sensor. A controller for controlling [preconditions],
As described in claim 5,
<a> a heat treatment detector that detects the start of the heat treatment of the object to be heated by the heater;
<b1> When the start of the heat treatment is detected by the heat treatment detection unit, the lowest drop value detection unit that detects the lowest drop value of the control amount PV given from the temperature sensor to the controller;
<c1> An operation amount upper limit determination unit that sets an upper limit value of the operation amount MV of the heater by the controller according to the lowest decrease value of the control amount PV detected by the lowest drop value detection unit. It is characterized by that.

  By the way, for the operation amount upper limit value determination unit, for example, refer to a table describing a predetermined relationship between the maximum drop value of the control amount PV and the upper limit value of the operation amount MV, or to a mathematical expression indicating the relationship. The upper limit value of the manipulated variable MV is determined by substituting the lowest drop value of the controlled variable PV. Note that the above relationship does not necessarily have to be linear, and when the lowest drop value of the control amount PV is not described in the table, an interpolation process is appropriately performed to obtain the upper limit value of the operation amount MV. It is enough.

Moreover, as described in claim 7, the temperature control device according to the present invention includes:
<a> a heat treatment detector that detects the start of the heat treatment of the object to be heated by the heater;
<b2> When the start of the heat treatment is detected by the heat treatment detection unit, a saturation time detection unit that detects a time during which the operation amount MV of the heater by the controller is saturated;
<c2> An operation amount upper limit determination unit that sets an upper limit value of the operation amount MV according to the saturation time of the operation amount MV detected by the saturation time detection unit.

  In this case, the operation amount upper limit determination unit is configured to obtain an upper limit value of the operation amount MV, for example, with a constant saturation time of the operation amount MV. Specifically, for example, the duration T2 in a state where the manipulated variable MV is saturated is measured, and the maximum value MV2 including the saturated state of the manipulated variable MV is obtained. After the amount MV reaches the maximum value MV2, a time T1 until it returns to the original operation amount MV1 is obtained. Based on these information T1, T2, MV1, and MV2, an upper limit value at which the saturation time of the manipulated variable MV becomes constant may be calculated.

Furthermore, the temperature control device according to the present invention is as described in claim 9,
<a> a heat treatment detector that detects the start of the heat treatment of the object to be heated by the heater;
<b3> a start operation amount detection unit that detects an operation amount MV of the heater by the controller at the start of the heat treatment when the start of the heat treatment is detected by the heat treatment detection unit;
<c3> An operation amount upper limit determination unit that sets an upper limit value of the operation amount MV according to the operation amount MV detected by the start operation amount detection unit is provided.

  In this case, the operation amount upper limit value determination unit sets the upper limit value of the operation amount MV as a value obtained by adding a constant value H to the operation amount MV at the start of the heating process detected by the start operation amount detection unit, for example. Configured to determine.

  According to the temperature control method and the control device of the present invention, paying attention to the control amount PV indicating the temperature of the heater, the state in which the heater temperature during the heat treatment rises due to heat storage in the heater is determined by the heater. Since the upper limit value for the manipulated variable MV is set according to the lowest drop value of the control amount PV after starting the heat treatment of the object to be heated, the heater is heated excessively. Disappears. Therefore, overheating of the heater can be simplified and effectively suppressed.

  In addition, paying attention to the operation amount MV for driving the heater, the upper limit value is set so that the time during which the operation amount MV is saturated is constant according to the operation amount MV at the start of heating. It is possible to prevent the amount of heat from being applied and to effectively suppress the overheating of the heater. That is, the upper limit value for the operation amount MV in the PID control is intended to limit the excessive amount of heat of the heater that is heated by the operation amount MV that is equal to or greater than the above upper limit value. This corresponds to the time during which the manipulated variable MV is limited by the upper limit value. Accordingly, when the time during which the operation amount MV is limited by the upper limit is short, the amount of heat limited to the heater is small, and conversely when the time is long, the amount of heat limited is large. It can be said.

  Therefore, as described above, the upper limit value for the operation amount MV is set according to the operation amount MV at the start of heating, and the time during which the operation amount MV is saturated is controlled to be constant. Regardless of the change in the operation amount MV, it is possible to make the limit amount of the amount of heat for heating the heater excessively constant. As a result, the heater is not heated excessively, and it is possible to simplify and effectively suppress the heater overheating.

  Alternatively, the upper limit value is set as a value obtained by adding a certain value to the operation amount MV in accordance with the operation amount MV at the start of the heat treatment. Therefore, when the heater temperature is high and the operation amount at the start of heating is low Since the upper limit value is also kept low, the heater is not heated excessively in the same manner. Therefore, overheating of the heater can be simplified and effectively suppressed.

[Focus on the invention]
When PID control is performed on the temperature of the heater, the amount of change in the operation amount MV corresponding to the change in the control amount PV detected by the temperature sensor with respect to a disturbance such as a sudden temperature drop is particularly proportional and differential. It rises sharply with great influence. The increase in the manipulated variable MV is an increase that is irrelevant to the gradual change in the manipulated variable MV due to, for example, a constant disturbance. For example, as described above, the heated object is heated by the pair of upper and lower heaters 2 and 3. This is unavoidable when the heater temperature is suddenly lowered by sandwiching 1.

  In such a case, for example, in the control operation with respect to the disturbance such as the lowering of the heater temperature during the first heat treatment of the article 1 to be heated by the heaters 2 and 3, generally, the rapid increase in the manipulated variable MV is: It is limited by the upper limit of the operation amount and is substantially suppressed. Therefore, the PID control parameter is normally set assuming an amount (the cut amount of the operation amount MV) that is limited by the above-described operation amount upper limit value of the operation amount MV obtained by the PID calculation.

  However, if the above-described sudden disturbance is repeatedly applied, the average value of the manipulated variable MV gradually declines, and due to this, the amount limited by the manipulated variable upper limit value (operated variable MV). ) Will gradually decrease. Then, based on the PID parameter set on the assumption that the change amount of the operation amount MV determined by the proportional operation and the differential operation is limited by the operation amount upper limit value (cut amount of the operation amount MV) as described above. The operation amount MV required in this way is gradually different. As a result, although the heater temperature is PID-controlled, the heater temperature gradually increases and reaches an overheated state.

The present invention focuses on the fact that the problems in the PID control system that occur under the situation where the above-described sudden disturbance is repeatedly caused solely by the change in the cut amount due to the operation amount upper limit value of the operation amount MV. In particular, in the present invention, rather than changing the PID control parameter in accordance with a change in the amount limited by the operation amount upper limit value by various verifications (the cut amount of the operation amount MV), the operation amount upper limit value itself is set in the situation. It has been found that the change according to the above can suppress the excessive temperature rise of the heater while maintaining the control characteristics by the PID control.
[Principle of Invention 1]
Therefore, in the first invention, the temperature of the heater for heating the object to be heated is set as a control amount PV, and when the operation amount MV for driving the heater is obtained according to the control amount PV, the driving of the heater is controlled. In particular, when the heating process of the object to be heated by the heater is started, the lowest drop value of the control amount PV is detected, and an upper limit value for the manipulated variable MV is set according to the lowest drop value of the control amount PV. It is characterized by.

That is, the first invention is based on the premise that when a disturbance that sharply lowers the temperature of the heater is applied, the control amount PV in the PID control system suddenly decreases and then overshoots the set value SP. . In order to prevent the heater from being heated excessively by overshoot, the operation amount MV for heating the heater according to the lowest drop value PVL of the control amount PV when the heating process of the object to be heated is started. The upper limit value OH is variably set. The relationship between the lowest drop value PVL of the control amount PV and the upper limit value OH of the manipulated variable MV may be registered in advance as a table, or may be given as a mathematical expression indicating the relationship.
[Principle of Invention 2]
Note that instead of focusing on the change in the control amount PV, it is possible to focus on the operation amount MV. That is, the upper limit value for the operation amount MV in the PID control is for limiting excessive heating of the heater by the operation amount MV that is equal to or greater than the upper limit value, and the amount of heat (cut) limited by the upper limit value is exclusively used. This corresponds to the time during which the manipulated variable MV is limited by the upper limit value. When the limit time of the operation amount MV by the upper limit value is short, the heat amount limit amount is small (a large amount of heat is given to the heater), and conversely when the limit time is long, the heat amount is large (the heater amount is increased). Less heat is given).

Therefore, in the second invention, when the heat treatment of the object to be heated by the heater is started, the time during which the manipulated variable MV is saturated, that is, the time during which the manipulated variable MV is limited by the upper and lower values is detected, The upper limit value OH for the manipulated variable MV is variably set according to the saturation time (time limit). Regardless of the change in the operation amount MV, the amount of cut with respect to the control amount MV at the upper limit value OH that limits the amount of heat given to the heater at the time of overshoot of the control response is kept constant, thereby preventing overheating of the heater. It is characterized by.
[Principle 3 of the invention]
The third invention pays attention to the operation amount MV itself at the start of the heat treatment, and variably sets the upper limit value OH according to the operation amount MV at that time. Specifically, the operation amount at the start of the heat treatment By setting a value obtained by adding a constant value H to MV as the upper limit value OH, the amount of heat given to the heater itself at the time of overshoot of the control response is kept constant regardless of the change in the operation amount MV, thereby overheating the heater It is characterized by preventing.
[First Embodiment of the Invention]
Next, the first embodiment according to the first invention will be described. The present invention is applied to an apparatus that heats an object to be heated 1 that is repeatedly and sequentially supplied as shown in FIG. 9 between a pair of upper and lower heaters 2 and 3. This is realized as a function incorporated in a temperature controller that has constructed a control system for PID control of the temperature of the heaters 2 and 3. When the heaters 2 and 3 whose temperature is suddenly lowered by the contact with the heated object 1 are driven under PID control, particularly when the heated object 1 is heated by the contact between the heated object 1 and the heaters 2 and 3. This is realized as a function for removing the influence of the temperature gradually stored in the heaters 2 and 3 due to the overshoot of the control response.

  FIG. 1 is a schematic configuration diagram showing a characteristic function of the present invention provided in the temperature control device according to the first embodiment. Here, a control mode for the lower heater 3 in which overheating due to heat accumulation is a problem is shown. Explained as an example. This temperature control device basically includes a heat treatment detection unit 11 that detects the start of the heat treatment of the article 1 to be heated by the heater 3 and the above-described heat treatment detected at the start of the heat treatment detected by the heat treatment detection unit 11. The lowest drop value detector 12 for detecting the lowest drop value PVL of the control amount PV in the PID control system is provided. The heat treatment detection unit 11 includes, for example, one that mechanically detects the sandwiching operation itself of the article 1 to be heated by the heaters 2 and 3 and one that detects a control signal that commands the sandwiching operation.

  The heating process detection unit 11 monitors the temperature (control amount PV) of the heater 3 detected by, for example, a temperature sensor to obtain a change amount (change slope) ΔPV per unit time. When ΔPV is larger than a preset threshold value, this may be detected as the start of the heat treatment. If attention is paid to such a change amount ΔPV per unit time of the control amount PV, the controllability in the above-described PID control can be reliably maintained.

  In addition, when the temperature of the heaters 2 and 3 (control amount PV) decreases due to contact with the object 1 to be heated, the lowest drop detection unit 12 performs PID control accordingly, and under this PID control, the PID control is performed. After the amount of control PV decreases most, the operation amount MV for the heater 3 changes with an overshoot, and the size of the overshoot depends on the lowest drop value PVL of the control amount PV. The lowest drop value PVL of the control amount PV at the start of processing is detected. The lowest drop value PVL is obtained, for example, by monitoring the control amount PV over a period in which the control amount PV is below a preset control target value SP and sequentially updating the minimum value. Of course, it is possible to obtain the minimum drop value PVL by monitoring the change amount ΔPV per unit time of the control amount PV described above.

  The temperature control device according to this embodiment is further based on the lowest drop value PVL of the control amount PV at the start of the heat treatment of the heated portion 1 by the heater 3 obtained by the lowest drop value detection unit 12 described above. For example, an operation amount upper limit determination unit 14 that variably sets an upper limit value OH for the operation amount MV of the heaters 2 and 3 in the PID control system described above with reference to the table storage unit 13 is provided.

  The table storage unit 13 describes the relationship between the lowest drop value PVL in the PID control system obtained in advance by experiments and the upper limit value OH of the operation amount MV that prevents the heater 3 from reaching an overheat state. For example, when the temperature of the lower heater 3 is controlled to 100 ° C. (SP = 100), the relationship shown in FIG. 2 (table 13a) is given. Here, the relationship between the lowest drop value PVL and the upper limit value OH is given as a linear one, but it may of course be a non-linear relationship. In addition, when the lowest drop value PVL detected by the lowest drop value detection unit 12 does not match the lowest drop value PVL of the table 13a described in the table storage unit 13, the interpolation process is performed from the relationship described in the table 123a. Of course, the upper limit value OH corresponding to the detected value of the lowest drop value PVL may be obtained.

Instead of describing the relationship (table 13a) between the lowest drop value PVL and the upper limit value OH of the manipulated variable MV using the table storage unit 13, a mathematical expression indicating the relationship can be expressed by, for example, OH = OHX−α ( PVL-PVX)
It is also possible to obtain the upper limit value OH in advance by substituting the lowest drop value PVL detected by the lowest drop value detection unit 12 into this mathematical expression. However, OHX is a reference upper limit value with respect to the upper limit value of the manipulated variable PV, and PVX is a reference value of the lowest drop value PVL. Specifically, when the control target temperature (set value) SP of the heater 3 is given as 100 ° C., the reference upper limit value OHX is set to [100] or the like, and the lowest drop reference value PVX is set to [95] or the like. Given. This formula shows the relationship between the lowest drop value PVL and the upper limit value OH, as in the table 13a shown in FIG.

  Thus, as described above, according to the first embodiment of the present invention in which the upper limit value OH for the manipulated variable MV is variably set according to the lowest drop value PVL of the controlled variable PV at the start of the heat treatment, FIG. As schematically shown in FIG. 5 (b), how the control amount PV and the operation amount MV change, the upper limit value OH of the operation amount MV according to the change in the lowest drop value PVL of the control amount PV caused by the repeatedly applied disturbance. Changes.

  That is, when a disturbance that drastically lowers the temperature of the heater 3 is periodically applied, the control amount PV is drastically lowered as shown in FIG. Due to the action, as shown in FIG. 3B, the manipulated variable MV for the heater 3 increases rapidly. Then, the control amount PV, which is the temperature of the heater 3, increases with the rapid increase of the operation amount MV, and after overshooting, it tries to return to the original temperature (set value SP). However, if the next disturbance is applied before the control amount PV, which is the temperature of the heater 3, returns to the original value under PID control, the temperature of the heater 3 (control amount PV) becomes the control target temperature (set value SP). ), The lowest temperature drop PVL before overshooting is higher than when the previous disturbance was applied. As a result, as shown in FIG. 3B, the manipulated variable MV for the heater 3 becomes smaller than the previous disturbance applied, and the manipulated variable MV is added to the heater 3 as it is without being limited by the upper limit value OH. Become. This phenomenon is a cause of the overheating state caused by the heat storage of the heater 3 described above.

  In this respect, in this embodiment, as shown in FIG. 3A, when the lowest drop value PVL at the time of sudden drop of the control amount PV caused by the application of the disturbance rises, it is described in the table storage unit 13 described above. In accordance with the relationship between the lowest drop value PVL and the upper limit value OH, the upper limit value OH for the manipulated variable MV is set to be reduced according to the highest drop value PVL that has increased. As a result, when disturbance is next applied as shown in FIG. 3B, the manipulated variable MV generated in accordance with the change in the controlled variable PV is limited by the upper limit value OH set to be reduced as described above. Thus, an excessive amount of heat is suppressed from being applied to the heater 3. And the overheating of the heater 3 is gradually suppressed by the suppression effect by the upper limit value OH of the control amount MV.

Therefore, according to this embodiment, even if the next disturbance is repeatedly applied before compensating for the temperature change of the heater 3 with respect to the disturbance under PID control, the heater 3 is overheated (unintentional temperature rise). Can be effectively suppressed. In particular, it is possible to suppress overheating (unintentional temperature rise) of the heater 3 only by variably setting the upper limit value OH with respect to the manipulated variable MV according to the lowest drop value PVL before the control amount PV overshoots. Is simple. In addition, the PID control parameter is not changed in accordance with the amount of heat accumulated in the heater 3, but the upper limit value OH for the manipulated variable MV is simply variably set, so that the temperature of the heater 3 is controlled while maintaining the PID control characteristics. be able to. Therefore, the temperature control of the heater 3 can be simplified and effectively executed, and the temperature can be optimized.
[Second Embodiment of the Invention]
By the way, in the first embodiment described above, the upper limit value OH for the manipulated variable MV is set by paying attention to the control amount PV and particularly paying attention to the lowest drop value PVL of the control amount PV before overshoot. In addition, the upper limit value OH of the operation amount MV can be variably set by paying attention to the operation amount MV before the overshoot. FIG. 4 is a schematic configuration diagram showing the characteristic functions provided in the temperature control device according to the second embodiment of the present invention focusing on such an operation amount MV.

  The temperature control device includes a heat treatment detection unit 21 that detects the start of the heat treatment of the article 1 to be heated by the heater 3 as in the first embodiment described above, and is heated by the heat treatment detection unit 21. A saturation time measurement unit 22 that is activated when the start of the process is detected and measures the saturation time of the manipulated variable MV at the start of the heat treatment is provided. In addition, the said heat processing detection part 21 consists of the thing similar to the heat processing detection part 11 in 1st Embodiment mentioned above.

  Incidentally, the saturation time measuring unit 22 is in a state in which the manipulated variable MV calculated by the PID according to the change in the controlled variable PV becomes the maximum value, and the manipulated variable MV is regulated by the above-described upper limit value OH and the maximum value ( The upper limit value) is detected as the duration T2 in which the manipulated variable MV is saturated. The saturation time measuring unit 22 simultaneously obtains a value (maximum manipulated variable) MV2 when the manipulated variable MV is saturated, and the manipulated variable MV is added to the original manipulated variable MV1, that is, a disturbance is added. The time T1 until the control amount PV is changed and the operation amount MV returns to the operation amount MV in the state before the operation amount MV is changed accordingly is also measured.

  Then, in the operation amount upper limit determination unit 23, the saturation time measurement unit 22 measures the operation amount upper limit determination unit 23 based on an expression indicating the relationship between the saturation time and the upper limit value OH that is obtained in advance and registered in the mathematical expression storage unit 24. From the saturation time T2 of the manipulated variable MV, the upper limit value OH for making the saturation time constant is calculated. The upper limit value OH set for the manipulated variable MV is updated with the upper limit value OH calculated by the manipulated variable upper limit determination unit 23, and the saturation time of the manipulated variable MV is constant in the subsequent temperature control routine. It becomes.

Specifically, the operation amount upper limit determination unit 23 considers that the change in the operation amount MV is linear as shown in FIG. 5, and the operation amount MV changes with the input of the disturbance. Is determined from the time T2 defined by the upper limit value OH and saturated, the maximum manipulated variable MV2 at that time, and the time T1 until the manipulated variable MV returns to the original value MV1 before the start of the PID operation. The upper limit value OH for obtaining the saturation time TX is OH = (MV2-MV1) (T1-TX) / (T1-T2) + MV1
Is calculated geometrically.

  Thus, according to the control system in which the upper limit value OH is set in this way, the control amount PV and the operation amount MV when a disturbance that rapidly decreases the temperature of the heater 3 is repeatedly applied to FIGS. 6 (a) and 6 (b). As schematically shown, the upper limit value OH that defines the manipulated variable MV calculated following the change in the controlled variable PV caused by the repeatedly applied disturbance stabilizes the saturation time of the manipulated variable MV. To change. That is, when the manipulated variable MV changes due to disturbance applied to the control system, the time T2 when the manipulated variable MV is saturated is measured, and the manipulated variable is set so that the saturation time is made constant according to the saturated time. The upper limit value OH for MV is changed. As a result, even if the next disturbance is applied before the control amount PV changed due to the disturbance returns to the original state, the saturation time of the manipulated variable MV is maintained by the upper limit value OH set as described above. The saturation time of the quantity MV is controlled to be constant.

Therefore, as in the first embodiment, even if the next disturbance is repeatedly applied before compensating for the temperature change of the heater 3 with respect to the disturbance under PID control, the heater 3 is overheated (unintentionally). Effective temperature rise) can be effectively suppressed. Further, since the saturation time of the manipulated variable MV is made constant, the amount of heat (cut) limited by the upper limit value OH among the amount of heat to be supplied to the heater 3 under PID control can be made constant. It is possible to control the temperature of the heater 3 with good control response without heating the heater 3 excessively. In particular, in this case, unlike the first embodiment, the control amount PV is not monitored, so that there is an advantage that the control effect appears earlier than in the first embodiment.
[Third Embodiment of the Invention]
By the way, when the upper limit value OH is variably set according to the operation amount MV, it is possible to more easily suppress overheating of the heater 3 by paying attention to the operation amount MV itself. FIG. 7 shows the embodiment, and shows a schematic configuration showing characteristic functions of the temperature control device.

  This temperature control apparatus includes a heat treatment detection unit 31 that detects the start of the heat treatment of the article 1 to be heated by the heater 3 as in the first embodiment described above, and is heated by the heat treatment detection unit 31. When the start of the process is detected, the operation amount MV at the start of the heat treatment, specifically, the start operation amount detection unit 32 that measures the value MV1 immediately before the operation amount MV changes with the start of the heat treatment is provided. . In addition, the said heat processing detection part 31 consists of a thing similar to the heat processing detection part 11 in 1st Embodiment mentioned above.

Then, in the operation amount upper limit determination unit 33, the start operation amount detection unit is calculated based on an expression indicating the relationship between the operation amount MV1 at the start of control and the upper limit value OH, which is obtained in advance and registered in the mathematical formula storage unit 34. The upper limit value OH corresponding to the operation amount MV1 measured at 32 is calculated. Specifically, the operation amount upper limit determination unit 33 adds a constant value H to the operation amount MV1 measured by the start operation amount detection unit 32,
OH = MV1 + H
The upper limit value OH is calculated as The upper limit value OH that has already been set for the manipulated variable MV is updated with the upper limit value OH calculated by the manipulated variable upper limit determination unit 23, and the maximum value of the manipulated variable MV is set in the subsequent temperature control routine. It is prescribed.

Thus, according to such an embodiment, how the control amount PV and the manipulated variable MV change when a disturbance that rapidly decreases the temperature of the heater 3 is repeatedly applied to FIGS. 8 (a) and 8 (b). As shown, the upper limit value OH that defines the manipulated variable MV calculated following the change in the controlled variable PV caused by the repeatedly applied disturbance is variably set according to the manipulated variable MV1 at the start of the control. As a result, even if the next disturbance is applied before the control amount PV changed due to the disturbance returns to the original state, the maximum value of the manipulated variable MV is suppressed by the upper limit value OH set as described above. Supply of an excessive amount of heat to is suppressed. Further, according to such a control system, since the upper limit value OH is variably set in real time according to the operation amount MV1 when the control operation is started due to disturbance, overheating of the heater 3 is suppressed without control delay. can do. Further, similarly to the above-described embodiments, there is an advantage that the control responsiveness can be sufficiently ensured because it is not necessary to change the PID control parameter.
[Other Embodiments of the Invention]
The present invention is not limited to the above-described embodiments. Here, the temperature control for the lower heater 3 has been described as an example, but the present invention can be similarly applied to the upper heater 2. Further, not only when the object to be heated 1 is sandwiched and heated by the pair of upper and lower heaters 2 and 3, but also when only one heater is provided and the heater is brought into contact with the object to be heated 1 for heating. Can do. In short, the present invention is suitable for application to a temperature control object such as a heater that is repeatedly subjected to a disturbance that suddenly lowers its temperature. As a device or the like additionally incorporated in the control system formed by the temperature controller, various modifications can be made without departing from the scope of the invention.

The schematic block diagram which shows the characteristic function of this invention with which the temperature control apparatus which concerns on the 1st Embodiment of this invention is provided. The figure which shows an example of the relationship between the lowest fall value PVL recorded on the table memory | storage part shown in FIG. 1, and the upper limit OH of the operation amount MV. The figure which shows typically the mode of the change of the controlled variable PV and the manipulated variable MV under control which concerns on 1st Embodiment. The schematic block diagram which shows the characteristic function of this invention with which the temperature control apparatus which concerns on the 2nd Embodiment of this invention is provided. The figure which shows the example of the determination method of the upper limit OH in the operation amount upper limit determination part shown in FIG. The figure which shows typically the mode of the change of the controlled variable PV and the manipulated variable MV under control which concerns on 2nd Embodiment. The schematic block diagram which the temperature control apparatus which concerns on the 3rd Embodiment of this invention shows. The figure which shows typically the mode of the change of the controlled variable PV and the manipulated variable MV under control which concerns on 3rd Embodiment. The figure which shows the example of the heating apparatus with which this invention is applied. The figure which shows the temperature change of the heater at the time of the disturbance application in the heating apparatus shown in FIG. The figure which shows typically the change of the controlled variable PV and the manipulated variable MV at the time of the disturbance application under PID control for demonstrating the form of the conventional temperature control, and its problem.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Heat processing detection part 12 Minimum drop value detection part 13 Table memory | storage part 14 Operation amount upper limit value determination part 21 Heat processing detection part 22 Saturation time measurement part 23 Operation amount upper limit value determination part 24 Numerical formula memory | storage part 31 Heat processing detection part 32 Start Operation amount detection unit 33 Operation amount upper limit determination unit 34 Formula storage unit

Claims (10)

When the temperature of the heater that heats the object to be heated is set as a control amount PV, and the operation amount MV for driving the heater is calculated according to the control amount PV, the driving of the heater is controlled.
When the heating process of the object to be heated by the heater is started, the lowest drop value of the control amount PV is detected, and an upper limit value for the operation amount MV is set according to the lowest drop value of the control amount PV. A characteristic temperature control method. When the temperature of the heater that heats the object to be heated is set as a control amount PV, and the operation amount MV for driving the heater is calculated according to the control amount PV, the driving of the heater is controlled.
When heating of the object to be heated by the heater is started, a time during which the operation amount MV is saturated is detected, and an upper limit value for the operation amount MV is set according to the saturation time. Temperature control method. When the temperature of the heater that heats the object to be heated is set as a control amount PV, and the operation amount MV for driving the heater is calculated according to the control amount PV, the driving of the heater is controlled.
When the heat treatment of the object to be heated by the heater is started, the operation amount MV at the start of the heat treatment is detected, and an upper limit value for the operation amount MV is set according to the operation amount MV at the start of the heat treatment. And a temperature control method. The heater is for heating the object to be heated in contact with the object to be heated,
The temperature control method according to claim 1, wherein the start of the heating process of the object to be heated by the heater is detected when the heater is in contact with the object to be heated. A temperature control device comprising a heater for heating an object to be heated, a temperature sensor for detecting the temperature of the heater, and a controller for controlling the driving of the heater based on the output of the temperature sensor,
A heat treatment detector for detecting the start of the heat treatment of the object to be heated by the heater;
When the start of the heat treatment is detected by the heat treatment detection unit, the lowest drop value detection unit that detects the lowest drop value of the control amount PV given from the temperature sensor to the controller;
An operation amount upper limit value determining unit that sets an upper limit value of the operation amount MV of the heater by the controller in accordance with the lowest drop value of the control amount PV detected by the lowest drop value detection unit. A temperature control device.   The manipulated variable upper limit value determining unit refers to a table that describes a relationship between a predetermined lowest drop value of the control variable PV and an upper limit value of the manipulated variable MV, or sets the control variable to a mathematical expression indicating the relationship. The temperature control device according to claim 5, wherein an upper limit value of the manipulated variable MV is determined by substituting the lowest PV drop value. A temperature control device comprising a heater for heating an object to be heated, a temperature sensor for detecting the temperature of the heater, and a controller for controlling the driving of the heater based on the output of the temperature sensor,
A heat treatment detector for detecting the start of the heat treatment of the object to be heated by the heater;
A saturation time detection unit for detecting a time when the operation amount MV of the heater by the controller is saturated when the start of the heat treatment is detected by the heat treatment detection unit;
A temperature control apparatus comprising: an operation amount upper limit determining unit that sets an upper limit value of the operation amount MV according to a saturation time of the operation amount MV detected by the saturation time detection unit.   The temperature control device according to claim 7, wherein the operation amount upper limit determination unit determines an upper limit value of the operation amount MV that makes a saturation time of the operation amount MV constant. A temperature control device comprising a heater for heating an object to be heated, a temperature sensor for detecting the temperature of the heater, and a controller for controlling the driving of the heater based on the output of the temperature sensor,
A heat treatment detector for detecting the start of the heat treatment of the object to be heated by the heater;
A start operation amount detection unit for detecting an operation amount MV of the heater by the controller at the start of the heat treatment when the start of the heat treatment is detected by the heat treatment detection unit;
A temperature control device comprising: an operation amount upper limit determination unit that sets an upper limit value of the operation amount MV according to the operation amount MV detected by the start operation amount detection unit.   The operation amount upper limit determination unit determines an upper limit value of the operation amount MV as a value obtained by adding a constant value H to the operation amount MV at the start of the heat treatment detected by the start operation amount detection unit. Item 10. The temperature control device according to Item 9.

Images