Control device, control program, and method for control

Abstract

To provide a novel technology for controlling temperature of a storage room in which a temperature sensor included in a vending machine is not installed can reach a target temperature.SOLUTION: A control device for a vending machine including a storage room in which a temperature sensor is installed and a storage room in which a temperature sensor is not installed uses the temperature of the storage room which is measured by the temperature sensor in the storage room in which the temperature sensor is installed to estimate temperature of the storage room in which the temperature sensor is not installed, and controls the measured temperature of the storage room and the estimated temperature of the storage room so that temperature of each storage room reaches a target temperature.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device, a control program, and a control method for controlling the temperature of products in a vending machine that sells temperature-controlled products such as beverages and food products. [Background technology]

[0002] Conventionally, vending machines have used a classical control method called PID (Proportional Integral Derivative) control as a temperature control method. This control method is an established control method, and therefore has high technical reliability and is widely used. For example, an example of such a technology is disclosed in Patent Document 1.

[0003] Patent Document 1 describes that an internal operation on / off determining unit 62 determines whether to turn internal operation on or off in accordance with the on / off temperature setting data stored in memory 61. Specifically, it describes that the internal temperatures of the product storage cabinets 4L, 4R measured by the heating internal temperature sensor 4L2 and the cooling internal temperature sensor 4R2 are compared with the on / off temperature setting, and whether to turn internal operation on or off is determined based on the comparison result. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-27783 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 required measuring the temperature using a temperature sensor installed in each storage compartment in order to control the operation of each storage compartment of the vending machine according to the set temperature of the storage compartment.

[0006] In view of the above problems, the present invention aims to provide a new technology for controlling the temperature of a storage cabinet in a vending machine that is not equipped with a temperature sensor so that it can reach a target temperature. [Means for solving the problem]

[0007] In order to solve the above problem, the present invention provides a control device for a vending machine having a storage cabinet with a temperature sensor installed and a storage cabinet without a temperature sensor installed, The temperature of a storage cabinet where the temperature sensor is installed, measured by the temperature sensor, is used to estimate the temperature of a storage cabinet where the temperature sensor is not installed, and the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet are controlled so that the temperature of each storage cabinet reaches a target temperature.

[0008] In order to solve the above problem, the present invention provides a control device for a vending machine having a storage cabinet in which a temperature sensor is not installed, The measured temperature outside the storage cabinet is used to estimate the temperature of a storage cabinet where no temperature sensor is installed, and the estimated temperature of the storage cabinet is controlled so that the temperature of the storage cabinet reaches a target temperature.

[0009] With this configuration, the temperature of the storage cabinet can be estimated without installing a temperature sensor in the storage cabinet, which significantly reduces the installation cost of the temperature sensor.

[0010] In a more preferred embodiment, the control device estimates the temperature of a storage cabinet in which the temperature sensor is not installed using an estimation model that includes parameters that control the vending machine's refrigerant, parameters that indicate the performance of the vending machine, and the temperature of the storage cabinet in which the temperature sensor is installed measured by the temperature sensor.

[0011] In a more preferred embodiment, the control device estimates the temperature of a storage compartment where the temperature sensor is not installed, using an estimation model including parameters for controlling the refrigerant of the vending machine, parameters indicating the performance of the vending machine, and the measured temperature outside the storage compartment.

[0012] With this configuration, it is possible to estimate the temperature of a storage cabinet in which no temperature sensor is installed by using an estimation model that includes parameters related to the vending machine.

[0013] In a more preferred embodiment, the estimation model includes a parameter U that controls the refrigerant of the vending machine, a parameter A that indicates the performance of the vending machine, a temperature y of the storage cabinet measured by the temperature sensor in the storage cabinet in which the temperature sensor is installed, an arbitrary scalar variable h, and a vector c having elements of 0 or 1,

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[0014] In a more preferred embodiment, the estimation model includes a parameter U that controls the refrigerant of the vending machine, a parameter A that indicates the performance of the vending machine, the measured temperature y outside the storage cabinet, an arbitrary scalar variable h, and a vector c whose elements are 0 or 1,

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[0015] With this configuration, the convergence of the storage temperature to be estimated can be improved by arbitrarily selecting the scalar variable h, which increases the calculation speed for temperature estimation and enables accurate control of the vending machine. [Effects of the Invention]

[0016] The present invention has the effect of providing a novel technique that enables operation of a vending machine taking into account multiple factors when making each storage compartment reach a target temperature. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a model predictive control block diagram according to an embodiment. [Figure 2] FIG. 1 is an explanatory diagram of a control horizon and a prediction horizon according to model predictive control in one embodiment. [Figure 3] FIG. 10 is a diagram showing the heat balance of a vending machine when taking into account the thermal resistance of a heat insulating material in one embodiment. [Figure 4] FIG. 1 is a diagram illustrating a thermal circuit network of a storage facility including thermal insulation in one embodiment. [Figure 5] 1 is a control block of the system in one embodiment. [Figure 6] FIG. 1 is a structural diagram of a typical vending machine. [Figure 7] FIG. 1 is a diagram illustrating the configuration of a storage cabinet in a typical vending machine. [Figure 8] FIG. 1 is a hardware configuration diagram of a control device of a general vending machine. [Figure 9] FIG. 1 is a principle diagram showing the seasonal operating conditions of a typical vending machine. [Figure 10] 1 is a block diagram of a cooling circuit in each operating state of a typical vending machine. FIG. [Figure 11] FIG. 1 is a diagram illustrating the principle of heat balance in a vending machine. [Figure 12] FIG. 1 is an explanatory diagram of a control algorithm for a conventional vending machine. [Figure 13] FIG. 10 is an explanatory diagram showing the transition of temperature control in a vending machine. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments are shown, but which may be embodied in many different forms and are not limited to the embodiments set forth herein.

[0019] For example, although the configuration, operation, etc. of the control device are described in this embodiment, methods, computer programs, etc. with similar configurations can also achieve similar effects. The program may also be stored on a recording medium. Using this recording medium, the program can be installed on a computer, for example, to configure the control device. Here, the recording medium storing the program may be a non-transitory recording medium, such as a CD-ROM.

[0020] <1. About general vending machines> The mechanism and processing operations of a typical vending machine will be described below with reference to FIGS.

[0021] <1.1. Vending machine structure> Figure 6 is a structural diagram of a typical vending machine. The vending machine in this embodiment is a vending machine that sells canned or bottled drinks, but it may also be a vending machine that sells food products. The vending machine shown in Figure 6 is equipped with a control device 1 and three storage compartments ST, which are separated by thermal insulation and are configured to reduce heat penetration between the storage compartments ST and from outside the vending machine (Figure 7).

[0022] <1.2. Hardware configuration of control device 1> 8 is a diagram showing the hardware configuration of the control device 1. The control device 1 includes a control unit 10, a storage unit 11, and a communication unit 12. The control unit 10 has a processor such as a CPU (Central Processing Unit) capable of executing an instruction set, and controls the overall operation and processing of the control device 1 by executing the control program and OS according to the present invention. The control unit 10 references the information stored in the memory unit 11 and performs tasks such as sending and receiving information from a currency discrimination processor for bills, coins, etc., sending and receiving temperature information from each storage compartment, issuing commands to the electronic expansion valve regarding valve opening, issuing display commands to the display device on the front of the vending machine, and monitoring the status of the push button switches. It also responds to commands from the operator. The storage unit 11 has a volatile memory such as RAM capable of storing an instruction set, and a non-volatile recording medium such as flash memory capable of recording an OS, control programs, etc., and stores setting parameters for the vending machine and the state of the vending machine. The communication unit 12 acquires the temperature measured by a measuring device such as a temperature sensor that measures the temperature of the installed storage cabinet, and transmits the temperature to the control unit 10. The communication unit 12 also transmits each command from the control unit 10 to each device of the vending machine. In this embodiment, the temperature of the storage cabinet is acquired from a measuring device external to the control device 1, but the temperature of the storage cabinet may also be acquired using a measuring device provided in the control device 1.

[0023] <1.3. Vending machine operation modes> In order to increase sales efficiency, canned and bottled beverage vending machines often switch operating modes to accommodate different beverage temperature ranges desired by users depending on the season. Figure 9 shows the operating modes of a vending machine equipped with three storage compartments. In Figure 9, the beverages shown in white are chilled cold beverages, while the beverages shown in gray are heated hot beverages.

[0024] In the spring and autumn seasons, one storage ST will heat the beverages stored therein and serve them as hot beverages, while the other two storage STs will cool the beverages and store them to sell as cold beverages. In winter, as more consumers desire hot beverages, the number of storage STs storing hot beverages will be increased to two, and the number of storage STs storing cold beverages will be reduced to one. In summer, all storage STs will be set to sell cold beverages.

[0025] The assumed ambient temperature, operating mode, and operating period for each season are summarized in Table 1. In addition, the ambient temperature outside the vending machine is assumed to be 15°C in spring and autumn, 32°C in summer, and 5°C in winter. As shown in Table 1, it can be seen that the operating mode in spring and autumn is the longest. [Table 1]

[0026] Generally, the operating mode of a vending machine is expressed by a combination of "C" (cold) and "H" (hot). Therefore, spring and autumn are HCC operation, summer is CCC operation, and winter is HHC operation.

[0027] In the internal structure diagram of the vending machine shown in Figure 6, the refrigeration unit is housed below the storage unit ST. Figure 9 shows the operation of the refrigeration unit in each operating mode. Each refrigeration circuit in Figure 10 is composed of a compressor CP, capillary coil CO, electronic expansion valve EEV, main heat exchanger MEX, heat exchanger EX in each storage unit, and solenoid valve EV connected by piping, and refrigerant flows through the piping. Figure 10(a) is a block diagram of the refrigeration circuit in the spring and autumn operating modes, Figure 10(b) is a summer operating mode, and Figure 10(c) is a block diagram of the refrigeration circuit in the winter operating mode, with arrows indicating the direction of refrigerant flowing through the piping.

[0028] <1.4. Heat balance of vending machines> Figure 11 is a diagram showing the principle of heat balance in a vending machine. The left chamber, located on the far left, is subject to heat intrusion from both the outside and the middle chamber, and the right chamber, located on the far right, is subject to heat intrusion from both the outside and the middle chamber. The middle chamber, located in the center, is subject to heat intrusion from both the left and right chambers in addition to heat intrusion from the outside.

[0029] Here, the heat capacity in the left ventricle is C L , the heat capacity in the middle chamber is C M , the heat capacity in the right ventricle is C R , and let the temperature outside the vending machine be T o , the temperature of the left ventricle is T L , the temperature of the central chamber is T M , the temperature of the right ventricle is T R Furthermore, the thermal penetration rate from the left chamber to the middle chamber is K LM The heat transmission rate from the middle chamber to the left chamber is K ML Similarly, for the right chamber, the heat transmission rate from the middle chamber to the right chamber is K MR Conversely, the thermal penetration rate from the right chamber to the middle chamber is K RM In addition, since each storage cabinet receives heat through the housing, the heat transmission rate from the outside air to the left compartment is set as K OL , the thermal penetration rate from the outside air to the middle room is K OM , the heat transmission rate from the outside air to the right chamber is K OR Far away.

[0030] Here, the amount of heat added to the left chamber for each storage ST by the output of the compressor CP is Q L , the amount of heat added to the middle chamber is Q M , the amount of heat added to the right ventricle is Q R Then, according to the first law of thermodynamics, an equation like Equation 1 holds true for each storage unit.

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[0031] <1.5. Conventional temperature control> Next, we will explain a conventional control method based on equation (1). Conventional vending machines use a method called feedback control. Here, feedback control is a method of controlling a controlled object by outputting 1 for an input of 1. For example, consider a system that includes a heated object, a measuring device, a power controller, and a heater. In this case, the measuring device measures temperature as input, calculates the amount of power to be supplied to the heater as output based on the difference between the measured temperature and the target temperature of the heated object, and the power controller supplies power to the heater according to the output value, causing the heater to change the temperature of the heated object. This type of temperature control method is called feedback control. Note that in order to explain the principles, only proportional control will be explained as a control method, and differential control and integral control will not be mentioned.

[0032] Figure 12 is a flowchart showing the basic algorithm of the software for controlling the temperature of each storage compartment in a vending machine. Figure 13 is a diagram showing an example of temperature control of each storage compartment based on the execution result of the following flowchart, taking an outside temperature of 32°C and CCC operation mode as an example.

[0033] First, in step S1 (hereinafter, "step SX" will be simply referred to as "SX"), a measuring device measures the temperature of each storage cabinet. In steps S2 to S4, the control unit 10 calculates the deviation between the target temperature of each storage cabinet and the measured temperature. Then, in steps S5 to S7, the control unit 10 sets the valve opening degree of the electronic expansion valve EEV of each storage cabinet based on the deviation of the temperature of each storage cabinet calculated in steps S2 to S4.

[0034] Next, in S8, the control unit 10 calculates the total load of the compressor CP. Here, there are two types of load on the compressor CP, the load during cooling and the load during heating, depending on the operation mode of the vending machine. If cooling is performed in normal operation and heating is performed using a heat pump, and for simplicity's sake, if we consider the cooling efficiency and heating efficiency to be equal, the compressor CP will require an output equivalent to the heat amount obtained by adding the cooling load and the heating load. The load is considered to be the sum of the absolute values of the required heat amount.

[0035] Then, in S9, the control unit 10 controls the compressor CP by setting the output of the compressor based on the load of the compressor CP calculated in S7. The control unit 10 then executes the processes of S2 to S9 until an instruction to turn off the operation is received (N in S10).

[0036] In this way, in the case of feedback control, by incorporating an electronic expansion valve EEV into the cooling circuit, which can control the amount of refrigerant flowing to each storage ST, a one-input, one-output relationship can be established, and temperature control can be performed according to each storage ST. In actual operation, the heat pump is operated in spring, autumn, and winter to heat beverages. In winter, when there are two compartments for heating beverages, for example, a left compartment and a middle compartment, and a right compartment for cooling beverages, the beverages in the right compartment may be cooled sufficiently, preventing the heat pump from operating. To avoid this situation, the left and middle compartments may be equipped with heaters to assist in heating.

[0037] On the other hand, for example, if there is a large difference between the target temperature and the temperature of the storage room, the compressor CP will operate at its maximum capacity, but there is a limit to the maximum capacity of the compressor CP, and it can only operate at the maximum capacity that consumes the most energy. Similarly, the compressor also has a minimum capacity, and it will operate at the minimum capacity when the difference between the target temperature and the minimum temperature is small. Feedback control cannot take into account such an operable range.

[0038] If a target time to be reached is set, it should be possible to operate the system in a way that takes into account energy consumption, and it would also be possible to control the system while taking into account maximum and minimum capacity at that time, but this type of control is difficult to achieve with feedback control.

[0039] In reality, vending machines tend to vary in usage time and sales volume depending on the environment in which they are installed. For example, vending machines installed in schools rarely sell products during class hours, but sell products primarily during breaks and lunch breaks. When this tendency exists, a vending machine with high sales efficiency would be one that minimizes power consumption during class hours and focuses on ensuring sufficient sales volume during breaks and lunch breaks, starting shortly before breaks and lunch breaks, in order to increase the number of products that can be sold. A vending machine capable of temperature control tailored to these time periods was needed.

[0040] <2. Temperature Control in Embodiment 1 of the Present Invention> The present invention relates to a control device that controls the temperature inside a vending machine using a control method called model predictive control. Model predictive control performs multi-input, multi-output control, and is capable of predicting the behavior of individual objects according to a set time. It can also manage the temperature of each storage compartment, called a state equation, as an independent index, allowing control according to each state.

[0041] In this invention, the target temperature of each storage compartment of the vending machine is predicted according to the set time, and the temperature of the vending machine is controlled based on the operating conditions according to the set time so that the temperature of the vending machine reaches the target temperature. For example, if the interval between the current time and the set time is sufficiently long, a large amount of energy is not required to bring the temperature of the vending machine to the target temperature at the set time, so the compressor is operated at a low speed to gradually control the temperature of the vending machine. On the other hand, if the interval between the current time and the set time is extremely short, a large amount of energy is required to bring the temperature of the vending machine to the target temperature at the set time, so the compressor is operated at a high speed to control the temperature of the vending machine so that the temperature of the vending machine reaches the target temperature quickly. In this embodiment, these operating conditions of the vending machine are optimized to control the temperature of the vending machine.

[0042] 2.1. Hardware configuration of the present invention The hardware configuration of the control device 1 in this embodiment is similar to the conventional hardware configuration shown in Fig. 8, and the control unit 10 executes a control program and an OS according to the present invention to perform model predictive control and control the compressor CP and the electronic expansion valve EEV. The cooling circuit is configured with devices similar to the circuit shown in Fig. 10. The control unit 10 may be realized by having a CPU or the like execute a program (i.e., realized by software), or may be realized by using a combination of software and hardware.

[0043] 2.2. Model predictive control In model predictive control, the idea is to use a weighted square of the solution obtained by solving the state equation as an evaluation function. Then, an index of the controlled object (variables in the system being handled) is determined so as to minimize this evaluation function. Therefore, by weighting according to the situation, it is possible to provide an optimal operating method. Below, a specific example of model predictive control is explained.

[0044] <2.2.1. Equation of state> Model predictive control is based on the following equation of motion, which uses parameters that control the refrigerant in the vending machine and parameters that indicate the performance of the vending machine: The parameters that control the refrigerant are the output heat quantity Q of the compressor CP, CP , left ventricular valve opening θ L , valve opening degree θ of the middle chamber M , and right ventricular valve opening θ R In addition, the thermal transmission rate K from the left chamber to the middle chamber is used as a parameter indicating the performance of the vending machine. LM , the thermal penetration rate from the middle chamber to the left chamber K ML , the thermal penetration rate from the middle chamber to the right chamber K MR , the thermal penetration rate from the right chamber to the middle chamber K RM , the heat capacity in the left ventricle C L , heat capacity in the middle chamber C M , and the heat capacity in the right ventricle C R Also, the input is Q CP , and the temperature outside the storage facility T O , the control parameter is θ L , θ M , and θ R , the output is the temperature of the left ventricle T L , the temperature of the middle compartment T M , and right ventricular temperature T R It is assumed that a measuring device is installed in each storage cabinet, and the temperature of each storage cabinet can be observed. In this embodiment, the temperature outside the storage cabinet is the ambient temperature in the installation environment of the vending machine, but it may also be the temperature outside the storage cabinet but inside the vending machine (for example, the temperature of the cooling unit).

[0045] With the symbols defined above, the state equation for each storage unit is as follows (t: time):

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[0046] Here, let U be a variable based on the parameters that control the refrigerant, and A be a constant based on the parameters that indicate the performance of the vending machine.

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[0047] <2.2.2. Evaluation Function> Model predictive control involves the idea of treating the magnitude of the input u(t) as energy and the output x(t) as an observable quantity (hereafter, the variable t will be omitted as appropriate), and using an evaluation function to evaluate the energy of the input u and the time response (magnitude of change) of the output x. In a vending machine, the input u is the valve opening θ of the electronic expansion valve EEV in each storage compartment. i (i=L, M, R), and the output x is the temperature T i (i=L, M, R).

[0048] The evaluation function is a function that evaluates the magnitude of the input u and output x. In the case of a vending machine, the evaluation function is a term weighted by the square of the power consumption of the compressor CP (the input u and the power consumption of the compressor CP are assumed to be proportional), which is the input u, and the temperature T of each storage compartment, which is the output x. iIt can be expressed as the integral from the current time to the target time of the sum of the terms where the square of ij , the output weighting coefficient Q ij Then, the evaluation function J(x, u, t) can be expressed as equation (8) (optimal regulator problem).

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[0049] <2.2.3. Weighting Coefficients Q and R> In this embodiment, the weighting factors Q and R can be freely set. Here, if R is set large relative to Q, the weight of the input energy u in the evaluation function J to be minimized will be large, resulting in a tendency to reduce the input energy u. Conversely, if Q is set large relative to R, the weight of the output x in the evaluation function J to be minimized will be large, resulting in a tendency to approach the target temperature more quickly. In this way, model predictive control enables the use of control tailored to the situation. In other words, the weighting factors Q and R are set as priorities for adjusting either the energy required to operate the vending machine or the operating state of the vending machine. Specifically, the weighting factor Q is an index (energy priority) that indicates that supplying energy to the vending machine is given priority over bringing the current temperature of the storage compartment closer to the target temperature. Meanwhile, the weighting factor R is an index (speed priority) that indicates that bringing the temperature of the storage compartment closer to the target temperature is given priority over bringing energy to the vending machine.

[0050] For example, as mentioned above, if the vending machine is installed in a school, there will be almost no sales during class hours, while sales will be concentrated during breaks and lunch breaks. When this tendency exists, control will be performed with a focus on reducing power consumption during class hours, and control will be performed with a focus on ensuring the number of vending machines available for sale during breaks and lunch breaks, starting shortly before the breaks and lunch breaks, so that the number of vending machines that can be sold can be increased. In other words, during class hours, priority will be given to reducing power consumption, and the weight of the energy priority Q will be set to be greater than the speed priority R, and during breaks and shortly before the lunch break, the weight of the speed priority R will be set to be greater than the energy priority Q.

[0051] In this way, by adjusting the energy priority Q and the quick response priority R of the evaluation function J, a vending machine with low power consumption and high sales efficiency can be realized. In this embodiment, the control unit 10 sets the weighting coefficients Q and R based on various factors and determines the evaluation function J (Equation (8)). The control unit 10 sets the weighting coefficients Q and R based on internal factors and / or external factors. Here, internal factors are factors that affect the operation of the vending machine itself, including one or both of maximum energy output and minimum energy output. Furthermore, external factors are factors that affect the operation of the vending machine from outside the vending machine, including human factors and environmental factors. Human factors are factors that are customary to humans, including one or more of the time of day, day of the week, holidays, installation location, the presence of organizations such as schools and companies in the vicinity of the installation location, and events held at the installation location. Furthermore, environmental factors are natural factors, including one or more of the season, weather, outside temperature, and humidity.

[0052] Specifically, the control unit 10 inputs one or more internal and external factors, weighting factors, and product purchase history into a learning model that predicts the values of the weighting factors Q and R to realize a vending machine with low power consumption and high sales efficiency, and sets the weighting factors Q and R by inputting one or more internal and external factors, and determines the evaluation function J. Alternatively, the control unit 10 may set the weighting factors Q and R using a correspondence table in which the values of one or more factors correspond to the weighting factors Q and R. Furthermore, a learning model may be used that predicts the values of the weighting factors Q and R by inputting usage frequency acquired by a human presence sensor installed in the vending machine in addition to or instead of the product purchase history.

[0053] 2.2.4. Example of Model Predictive Control Next, an embodiment of model predictive control will be described. Figure 1 is a block diagram showing the process of model predictive control executed by the control unit 10. First, a target value (a set value in the illustrated example) is given. In the case of a vending machine, the target value is the target temperature of each storage compartment.

[0054] First, the target temperature is sent to the control unit 10, where two calculations are performed: the first is to substitute the actually measured temperature of each storage compartment into the state equation (equation (5)) to calculate the solution of the differential equation (storage compartment temperature and valve opening) (prediction model). The second is to input the target temperature and target time to identify a solution that minimizes the evaluation function J (optimizer), since the vending machine aims to approach the target as quickly as possible using as little energy as possible. The prediction model and optimizer then periodically perform these calculations (hereinafter referred to as prediction processing) to predict how the storage compartment temperature will change. In this embodiment, since the temperature prediction target is air and the time constant of air is large, the prediction processing is performed, for example, every minute. This makes it possible to predict the temperature of the storage cabinet without increasing the frequency of calculations.

[0055] Specifically, the control unit 10 calculates one or more solutions (temperatures and valve openings of each storage compartment from the current time to the target temperature) by substituting the actually measured temperatures and valve openings of each storage compartment into the state equation (equation (5)) and solving simultaneous differential equations using a well-known solver (such as Newton's method).The control unit then calculates the value of evaluation function J by substituting each calculated solution, target time, and target temperature into evaluation function J (equation (8)) with weighting coefficients Q and R set.Then, from among the multiple solutions for temperature and valve opening, a solution that minimizes the calculated value of evaluation function J is identified.

[0056] The control unit 10 then controls the electronic expansion valve EEV by inputting the solution that minimizes the value of the evaluation function J as a control input to the controlled device (electronic expansion valve EEV). After a predetermined time has elapsed, the control unit 10 executes the prediction process again based on the temperature of the storage cabinet that is actually measured, and predicts the temperature change of the storage cabinet.

[0057] FIG. 2 is an explanatory diagram showing the control input optimized and determined by the optimizer, and the results of calculations of what the output will be from the present until a finite time later when that control input is input into the state equation.

[0058] Figure 2(a) shows, using the school example given above, an example in which control is performed from a time shortly before the break or lunch break, with the focus on ensuring the number of bottles sold. From a time shortly before the break or lunch break (target time) (for example, 10 minutes before) until the target time, the speed priority R of the evaluation function J is set relatively large and the energy priority Q is set relatively small, thereby increasing the temperature gradient from the current temperature of the storage room to the target temperature, and controlling the temperature of the storage room to reach the target temperature. This ensures that the target temperature is achieved by the target time, thereby ensuring the number of vending machines sold.

[0059] Figure 2(b) shows an example of a similar school where control is performed to gradually bring the temperature closer to the target temperature during the time between classes, when it is difficult to ensure the number of beverages sold. From the time between classes (current time) until just before (for example, 10 minutes before) the break or lunch break (target time), the energy priority Q of the evaluation function J is set relatively large and the speed priority R is set relatively small, thereby reducing the temperature gradient from the current temperature of the storage room to the target temperature and controlling the temperature of the storage room to reach the target temperature. This allows the vending machine to operate with priority given to energy consumption until there is sufficient time until the target time, thereby achieving energy savings. Here, the temperature gradient refers to the slope of the temperature at each time when the temperature in the storage cabinet is expressed as a function of time.

[0060] As described above, by using model predictive control, it is possible to appropriately set energy priority and speed priority in accordance with internal and / or external factors, thereby achieving low-power operation and high sales efficiency in vending machines.

[0061] In this embodiment, the energy priority and the quick response priority are set according to internal factors and / or external factors. Alternatively, the energy priority and the quick response priority may be configured to be set wirelessly from a terminal of a manager who manages the vending machines.

[0062] <4. Temperature Control in Embodiment 2 of the Present Invention> In the first embodiment, the temperature of the storage cabinets was predicted by substituting the temperatures measured by the measuring devices installed in each storage cabinet into a differential equation. In this embodiment, the temperature of the storage cabinets is predicted by substituting the temperatures measured by the measuring devices installed in at least one of the multiple storage cabinets into a differential equation. Alternatively, not all storage cabinets are equipped with measuring devices, and the temperature of the storage cabinets is predicted by substituting only the acquired outside air temperature into the differential equation. To achieve such temperature prediction, a method called an observer can be adopted.

[0063] An observer is a mechanism that estimates unobservable or non-observable parameters based on the output obtained from the system to be predicted (in this invention, a vending machine). In other words, by introducing an observer into the control of a vending machine, the state variable of the system (in this invention, the temperature of the storage compartment) can be obtained without directly observing it. The example shown in Figure 3 is an example using a block diagram for control using state feedback, rather than the model predictive control shown so far. There are issues with state feedback control, such as whether it is performed stably and whether real-time performance is impaired if convergence takes a considerable amount of time. When an observer is applied to state feedback control, the convergence of errors and other factors are theoretically established, so output can be estimated stably.

[0064] <4.1. Observer Description> Now the equation of state is

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[0065] In the system under consideration, we assume that the matrix A, coefficient b, and input vector u(t) are known, but the state vector x(t) cannot be observed and is therefore unknown. Furthermore, the state vector of the observer in this system (matrix A, coefficient b, input vector u(t)) is x~(t) (state estimate), and the state equation of the observer is given as follows:

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[0066] <4.2. Estimation of the state vector of the system to be predicted from the state vector of the observer> Next, we will show the relationship between the observer's state vector x~(t) and the state vector x(t) to be predicted. The error e(t) between the true measurement value (state variable of the system to be predicted) x(t) and the observer's state variable x~(t) is

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[0067] 4.3. Introduction of a more appropriate observer state equation Note that the convergence speed of the error (Equation (15)) in the state equation of Equation (12) depends only on the eigenvalue of A, and the speed at which the state vector x(t) is estimated cannot be adjusted. Therefore, in order to adjust the convergence speed of the observer, a new observer is configured as follows, using a new output vector c and the output y(t) of the system to be predicted.

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[0068] Considering the time derivative of the error at this time,

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[0069] 4.4. Observer Effect The observer is also called an observation device, and by using this concept, it becomes possible to estimate the temperature of the left and right compartments from the observation results of the measuring device in the middle compartment, which reduces the cost of the measuring device and the cost of wiring in the left and right compartments, thereby reducing costs. Furthermore, if the accuracy of the model is improved, it will be possible to estimate the temperature of each storage unit using only an outside air temperature sensor.

[0070] In the above description, an observer is used in the state feedback control system, but in a more preferred embodiment, it can also be used in the model predictive control of the first embodiment.

[0071] Here, if the system to be controlled is expressed as a discrete-time system,

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[0072] Therefore, if the pair (L, C) is observable, the eigenvalues of the observer can be placed at any position on the complex plane by selecting an appropriate gain L. The problem of determining this gain L is similar to the problem of finding the observer gain in state feedback control shown above. Figure 5 is a block diagram showing the observer in model predictive control.

[0073] In this embodiment, an observer is used to estimate the state vector in the system to be predicted, but a method other than the observer, such as a Kalman filter or inverse problem analysis, may also be used. [Explanation of symbols]

[0074] 1: Control device ST: Storage CP: Compressor MEX: Main heat exchanger CO: Capillary coil EEV: Electronic Expansion Valve EV: Solenoid valve 10: Control section 11: Storage section 12: Communications Department

Claims

1. A control device for a vending machine having a storage cabinet with a temperature sensor installed and a storage cabinet without a temperature sensor installed, A control device that uses the temperature of a storage cabinet in which the temperature sensor is installed measured by the temperature sensor to estimate the temperature of a storage cabinet in which the temperature sensor is not installed, and controls the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet so that the temperature of each storage cabinet reaches a target temperature.

2. A control device for a vending machine having a storage cabinet in which a temperature sensor is not installed, A control device that uses the measured temperature outside a storage cabinet to estimate the temperature of a storage cabinet that does not have a temperature sensor installed, and controls the estimated temperature of the storage cabinet so that the temperature of the storage cabinet reaches a target temperature.

3. The control device according to claim 1, wherein the control device estimates the temperature of a storage cabinet in which the temperature sensor is not installed using an estimation model including parameters for controlling the refrigerant of the vending machine, parameters indicating the performance of the vending machine, and the temperature of the storage cabinet in which the temperature sensor is installed measured by the temperature sensor.

4. The control device according to claim 2, wherein the control device estimates the temperature of a storage compartment in which the temperature sensor is not installed using an estimation model including parameters for controlling the refrigerant of the vending machine, parameters indicating the performance of the vending machine, and the measured temperature outside the storage compartment.

5. The estimation model includes a parameter U that controls the refrigerant of the vending machine, a parameter A that indicates the performance of the vending machine, a temperature y of the storage cabinet measured by the temperature sensor in the storage cabinet in which the temperature sensor is installed, an arbitrary scalar variable h, and a vector c whose elements are 0 or 1, [Equation 1] The control device according to claim 3, wherein the temperature x~ of a storage room where the temperature sensor is not installed is estimated using the above.

6. The estimation model includes a parameter U that controls the refrigerant of the vending machine, a parameter A that indicates the performance of the vending machine, the measured temperature y outside the storage cabinet, an arbitrary scalar variable h, and a vector c whose elements are 0 or 1, [Equation 2] The control device according to claim 4, wherein the temperature x~ of a storage room where the temperature sensor is not installed is estimated using the above.

7. A control program for a vending machine having a storage compartment with a temperature sensor and a storage compartment without a temperature sensor, The control program is executed by a computer. A control program that uses the temperature of a storage cabinet in which the temperature sensor is installed measured by the temperature sensor to estimate the temperature of a storage cabinet in which the temperature sensor is not installed, and controls the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet so that the temperature of each storage cabinet reaches a target temperature.

8. A method for controlling a vending machine having a storage compartment with a temperature sensor installed and a storage compartment without a temperature sensor, The computer A control method in which the temperature of a storage cabinet in which the temperature sensor is installed is used to estimate the temperature of a storage cabinet in which the temperature sensor is not installed, and a process is performed to control the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet so that the temperature of each storage cabinet reaches a target temperature.

9. A control program for a vending machine having a storage cabinet in which a temperature sensor is not installed, The control program is executed by a computer. A control program that uses the measured temperature outside the storage cabinet to estimate the temperature of storage cabinets where the temperature sensor is not installed, and controls the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet so that the temperature of each storage cabinet reaches a target temperature.

10. A method for controlling a vending machine having a storage cabinet in which a temperature sensor is not installed, The computer A control method that uses the measured temperature outside a storage cabinet to estimate the temperature of a storage cabinet where the temperature sensor is not installed, and performs a process to control the measured temperature of the storage cabinet and the estimated temperature of the storage cabinet so that the temperature of the storage cabinet reaches a target temperature.

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