Temperature control device, temperature control system, and temperature control method

Abstract

To provide a temperature controller, a temperature control system, and a method for controlling a temperature which can control the temperature of a fluid in a predetermined position to a target value even when the temperature sensor has been displaced.SOLUTION: The present disclosure includes: a feedback control unit for determining the control temperature of a fluid on the basis of the measurement temperature of a fluid measured by a temperature sensor; and a time-space compensation unit for compensating for the influence of the disturbance from a control position for controlling the temperature of the fluid to a predetermined position for arrival of the fluid with respect to the control temperature from the feedback control unit. The time-space compensation unit acquires the measurement temperature and changes the compensation value on the basis of the acquired temperature.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to temperature control techniques for in-pipe fluid transport systems. [Background technology]

[0002] An example of an in-pipe fluid transport system is a water sprinkler snow melting system used to prevent snow accumulation on tracks and roads. Water sprinkler snow melting systems transport heated water through pipes and spray it at a desired temperature to melt snow and prevent snow accumulation on tracks and roads. In railway systems, the temperature of the water supply system in the pipes is controlled to keep the water temperature on the tracks at 8 to 12°C. For example, feedback control is performed by measuring the temperature of the return water recovered after sprinkling and maintaining the temperature of the return water constant [see, for example, Non-Patent Document 1]. Furthermore, by combining this with feedforward control, temperature control that is highly responsive and resistant to external disturbances such as temperature changes is achieved [see, for example, Non-Patent Document 2].

[0003] To improve the delay in detecting fluid temperature changes, instead of measuring the temperature of the returned fluid, it is possible to install a temperature sensor at a predetermined position in the pipeline and feed back temperature information using a communication network. However, if the temperature sensor is installed inside the pipeline or at the pipeline outlet, the fluid temperature at the predetermined position cannot be detected due to misalignment of the temperature sensor, which causes a problem of degraded compensation performance for transport delays in temperature control. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Oki Yasuki, "Snow-melting equipment using sprinklers on the Tohoku Shinkansen (between Hachinohe and Shin-Aomori)," Construction Planning, vol. 745, pp. 39-47, March 2012. [Non-patent document 2] K. Sawase, K. Sasaki, S. Ohno, and Y. Kurosaki, "Feedforward Control of Track Water Sprinkler Snow Melting," Transactions of the Japan Society of Mechanical Engineers, Series C, vol. 57, no. 538, pp. 1979-1984, June 1991. Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in consideration of these problems, and the purpose of the present disclosure is to provide a temperature control device, a temperature control system, and a temperature control method that can control the fluid temperature at a specified position to a target value even if the temperature sensor is misaligned. [Means for solving the problem]

[0006] In this disclosure, the effects of transport delay and temperature sensor misalignment are estimated collectively as spatiotemporal phase disturbances in the temperature dimension from the difference between the control target model and the actual control response, and compensation is performed to prevent deterioration of compensation performance for fluid transport delay in temperature control. This makes it possible to control the fluid temperature at a predetermined position to a target value even if the temperature sensor is misaligned.

[0007] Specifically, the temperature control system of the present disclosure includes: a temperature control device according to the present disclosure; a temperature sensor for measuring the temperature of the fluid; Equipped with.

[0008] Specifically, the temperature control device of the present disclosure includes: a feedback controller that determines a control temperature of the fluid based on the measured temperature of the fluid measured by the temperature sensor; a time-space compensation unit that compensates for the influence of disturbances from a control position that controls the temperature of the fluid to a predetermined position where the fluid reaches, with respect to the controlled temperature from the feedback controller; The spatiotemporal compensation unit acquires the measured temperature and changes a compensation value based on the acquired temperature.

[0009] Specifically, the temperature control method of the present disclosure includes: a feedback controller determining a control temperature of the fluid based on the measured temperature of the fluid measured by the temperature sensor; a step in which a time-space compensation unit compensates for an influence of a disturbance on a controlled temperature from the feedback controller from a control position that controls the temperature of the fluid to a predetermined position where the fluid reaches; The spatiotemporal compensation unit acquires the measured temperature and changes a compensation value based on the acquired temperature. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a temperature control device, a temperature control system, and a temperature control method that can control the fluid temperature at a predetermined position to a target value even if the temperature sensor is misaligned. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an example of a system configuration for controlling the temperature of an in-pipe fluid transportation system. [Figure 2] FIG. 1 is a temperature control block diagram of an in-pipe fluid transport system. [Figure 3] FIG. 1 is a temperature control block diagram of an in-pipe fluid transport system that implements a Smith predictor. [Figure 4] 10 is an explanatory diagram of temperature control of an intrapipe fluid transportation system when a temperature sensor is moved from a predetermined position. FIG. [Figure 5] FIG. 10 is a temperature control block diagram implementing a Smith predictor for an in-pipe fluid transport system when a temperature sensor is moved from a predetermined position. [Figure 6] FIG. 1 is an explanatory diagram of temperature control of an in-pipe fluid transport system according to the present disclosure. [Figure 7] FIG. 10 is a temperature control block diagram implementing a spatiotemporal phase difference observer of the in-pipe fluid transport system of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0013] (System configuration of the present disclosure) The system configuration of the present disclosure is shown in Figure 1. The temperature control system of the present disclosure includes a temperature sensor 92 arranged in a pipe 91 and a temperature control device 10. The temperature sensor 92 is installed at a predetermined position x0 from the entrance of the pipe 91. The temperature control device 10 determines whether the temperature of the fluid at the predetermined position x0 is equal to or exceeds a target temperature θ(t) based on the temperature θ(t) measured by the temperature sensor 92. t The temperature θ(t,0) of the fluid flowing into the pipe 91 is controlled so that the temperature θ(t,0) becomes (t).

[0014] The temperature control device 10 of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network. The program of the present disclosure is a program for causing a computer to realize each functional unit of the temperature control device 10 according to the present disclosure, and is a program for causing a computer to execute each step of the method executed by the temperature control device 10 according to the present disclosure.

[0015] A fluid moves through the pipe 91 from the inlet to the outlet of the pipe 91 at an average speed v, and the temperature θ(t, x0) at a predetermined position x0 in the pipe 91 at time t is set to a target temperature θ t The temperature control device 10 controls the temperature to a target temperature θ t (t) and the measured temperature θ(t) obtained from the temperature sensor 92, the control temperature θ i (t) is determined. Control temperature θ i (t) is, for example, when the control position for controlling the temperature of the fluid is the inlet of the pipeline (x=0), the fluid temperature θ i (t)=θ(t,0).i By changing (t), the temperature θ(t, x0) at the specified position x0 becomes the target temperature θ t The measured temperature θ(t) is fed back to the temperature control device 10 via a communication network.

[0016] The fluid temperature at time t and position x is θ(t, x), and the ambient temperature in contact with the pipe 91 is θ a Assuming that the temperature is spatially uniform at (t), the ambient temperature θ a (t) is the disturbance (ambient temperature disturbance) θ that changes the fluid temperature due to heat transfer through the wall of the pipe 91. dis (t, x). With the Laplace operator s, the fluid temperature θ(s, x) at position x in the Laplace domain is expressed as follows:

number

[0017] The conventional system model is shown in Figure 2. However, in the block diagram, the target temperature at a given position x0 is set as θ x0 t , the fluid temperature is θ x0 , the ambient temperature disturbance is θ x0 dis As the temperature control device 10, for example, a feedback controller 11 capable of performing integral proportional-derivative leading control (I-PD control) as shown in FIG. 2 can be implemented. However, K p , K. i , K. d are the proportional gain, integral gain, and differential gain, respectively. K p , K. i , K. d For example, x0 / v≒0, θ x0 dis 1+K so that critical damping occurs when ≒0 p ≒2(K d K i ) 0.5The temperature control device 10 can be designed to satisfy the relationship: As the feedback controller 11 implemented in the temperature control device 10, any feedback controller other than the I-PD controller can be implemented.

[0018] In the system model of Fig. 2, the introduction of a Smith predictor 113 can be considered as a method for compensating for the transport delay exp(-x0 / v·s) from the control position x=0 to the specified position x0. Fig. 3 shows a temperature control block diagram in which a feedback controller 11 and a Smith predictor 113 are implemented within a temperature control device 10.

[0019] The Smith predictor 113 calculates the control temperature θ i is input, and θ i The difference between the first and second signals obtained using x0 cmp The first signal is calculated as the control object model exp(-ax0 / v) excluding transport delay and θ i The second signal is the output temperature when the transport delay is included in the control model exp(-ax0 / v)exp(-x0 / v s). i This represents the output temperature when

[0020] Compensation value θ x0 cmp The measured temperature θ at a given position is fed back. x0 This cancels out the feedback signal affected by the transport delay. As a result, the term due to the transport delay can be removed from the denominator of the closed-loop transfer function in the temperature control block diagram, making it possible to design a stable control system when the influence of ambient temperature disturbances is relatively small.

[0021] Next, consider the case in which, in the configuration of Figure 1, temperature sensor 92 moves from predetermined position x0 to position x1 for some reason. Possible causes of the movement include human mischief or being carried away by the movement of a fluid. The system configuration in this case is shown in Figure 4. The temperature measured by temperature sensor 92 at time t is the temperature θ(t, x1) at position x1, and this information is fed back via a communication network to temperature control device 10, which has a built-in Smith predictor 113. However, the temperature θ(t, x0) at predetermined position x0 cannot be measured directly.

[0022] FIG. 5 shows the temperature sensor 92 moving from a predetermined position x0 to a position x1, and the measured temperature θ x1 is transmitted to the feedback controller 11. The control object model in the Smith predictor 113 is a temperature control block diagram in which the measured temperature θ x0 Since the design is based on the assumption that θ is measured, modeling errors occur, and the feedback signal affected by the transport delay is cancelled out. x0 The target temperature θ x0 t It becomes difficult to control the

[0023] (Embodiments of the present disclosure) 6 shows a system configuration according to an embodiment of the present disclosure. In the configuration of FIG. 4, the temperature control device 10 has a built-in Smith predictor 113, but in the configuration of this embodiment, a space-time phase difference observer 14 that functions as a space-time compensation unit is built in instead of the Smith predictor 113. In this embodiment, the space-time phase difference observer 14 collectively estimates the effects of transport delay and misalignment of the temperature sensor 92 as space-time phase disturbances, suppresses feedback signals affected by transport delay and misalignment of the temperature sensor 92, and calculates θ x0 The target temperature θ x0 t Control to.

[0024] 7 is a temperature control block diagram that implements the spatiotemporal phase difference observer 14 of the present disclosure. The feedback controller 11 and the spatiotemporal phase difference observer 14 are implemented in the temperature control device 10. The spatiotemporal phase difference observer 14 calculates the control temperature θ i and the measured temperature θ x1 is input, and θ i The first signal and the measured temperature θ x1 The compensation value θ stpo cmp Here, the first signal is calculated by multiplying θ by the control object model exp(-ax0 / v) at the predetermined position x0 excluding the transport delay. i The spatiotemporal phase difference observer 14 calculates the output temperature when the first signal and the measured temperature θ x1 The difference is filtered by a low-pass filter g stpo / (s+g stpo ) to obtain the compensation value θ stpo cmp may be calculated.

[0025] However, g stpo is the cutoff frequency of the low-pass filter, and is set taking into consideration the control band and measurement noise. Here, an example is shown in which a first-order low-pass filter is used, but a higher-order low-pass filter may also be used. The compensation value θ stpo cmp The measured temperature θ at the position x1 is fed back. x1 By adding to the feedback signal, it is possible to suppress the effects of transport delays and sensor misalignment.

[0026] As a result, it is possible to remove the term due to transport delay from the denominator of the closed-loop transfer function in the temperature control block diagram, and further remove the effect of the spatial phase shift associated with the movement of the temperature sensor 92, making it possible to design a stable control system when the effect of ambient temperature disturbance is relatively small. In order to improve the robustness of the time-space phase difference observer 14 against disturbances, it is also possible to use in combination a disturbance compensator such as a disturbance observer that nominalizes the controlled object.

[0027] (effect) The present disclosure estimates and compensates for the effects of transport delay and temperature sensor misalignment collectively as a temperature-dimensional spatiotemporal phase disturbance from the difference between the control object model and the actual control response. As a result, even if the temperature sensor 92 is misaligned, the present disclosure can control the fluid temperature at a predetermined position to a target value without installing a sensor for measuring the position of the temperature sensor 92 on the temperature sensor 92.

[0028] In this embodiment, the predetermined position x0 is one location, but it may be two or more locations. Furthermore, the position x1 after movement is any location within the pipeline 91, and may be upstream or downstream of the fluid. [Industrial Applicability]

[0029] The present disclosure can be applied to the information and communications industry. [Explanation of symbols]

[0030] 10: Temperature control device 11: Feedback controller 14: Spatiotemporal phase difference observer 91: Pipeline 92: Temperature sensor 113: Smith Predictor

Claims

1. a feedback controller that determines a control temperature of the fluid based on the measured temperature of the fluid measured by the temperature sensor; a time-space compensation unit that compensates for the influence of disturbances from a control position that controls the temperature of the fluid to a predetermined position where the fluid reaches, with respect to the controlled temperature from the feedback controller; The spatiotemporal compensation unit calculating a first signal by inputting the control temperature θ i into a control object model at the predetermined position excluding a transport delay from the control position to the predetermined position; calculating a difference between the first signal and the measured temperature θ x1 ; the difference is passed through a low-pass filter to obtain a compensation value θ stpo cmp , which is then added to the measured temperature θ x1 , and the result is input to the feedback controller; Temperature control device.

2. If the fluid moves with an average velocity v, then, with a being a constant, the predetermined position x ０ The control object model excluding the transport delay is exp(-ax ０ / v), The temperature control device according to claim 1 .

3. The temperature control device according to claim 1 or 2; a temperature sensor that measures the temperature of the fluid; A temperature control system comprising:

4. a feedback controller determining a control temperature of the fluid based on the measured temperature of the fluid measured by the temperature sensor; a step in which a time-space compensation unit compensates for an influence of a disturbance on a controlled temperature from the feedback controller from a control position that controls the temperature of the fluid to a predetermined position where the fluid reaches; The spatiotemporal compensation unit calculating a first signal by inputting the control temperature θ i into a control object model at the predetermined position excluding a transport delay from the control position to the predetermined position; calculating a difference between the first signal and the measured temperature θ x1 ; the difference is passed through a low-pass filter to obtain a compensation value θ stpo cmp , which is then added to the measured temperature θ x1 , and the result is input to the feedback controller; Temperature control method.

5. A program for causing a computer to realize the functional unit of the temperature control device according to claim 1 or 2.

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