Aerosol generating device and control method

Abstract

This aerosol generation device comprises: a heating unit that heats an aerosol source; a power supply that supplies electric power to the heating unit; a thermistor that outputs a value dependent on the temperature of the heating unit; and a control unit that controls the supply of electric power from the power supply to the heating unit in accordance with a control sequence that includes a first interval in which a target value in temperature control is set to a value corresponding to a first temperature and electric power is supplied to the heating unit, a second interval in which the supply of electric power is stopped such that the temperature of the heating unit falls toward a second temperature lower than the first temperature, and a third interval in which electric power is supplied to the heating unit. The control unit controls the supply of electric power from the power supply in the first and third intervals using a first temperature index based on the electrical resistance value of the heating unit, and determines a timing at which to end the second interval using a second temperature index based on an output value from the thermistor.

Description

[Technical field]

[0001] The present disclosure relates to an aerosol generating device and a control method. [Background technology]

[0002] Electrically heated aerosol generating devices are known that generate aerosol by heating an aerosol source and deliver the generated aerosol to a user. For example, an electronic cigarette is one such aerosol generating device, and generates an aerosol containing a flavor component and is inhaled by the user.

[0003] The amount of aerosol generated from an aerosol source per unit time varies depending on the nature and shape of the substrate containing the aerosol source as well as the temperature at which the substrate is heated. Therefore, the aerosol generating device controls the heating temperature so that the amount of aerosol delivered to the user is a desired amount. In general, a representation of the change in temperature over time is called a temperature profile, and a time-series definition of the temperature control specifications for achieving a desired temperature profile is called a heating profile.

[0004] For example, Patent Document 1 discloses a temperature profile in which the temperature of the heating element is increased to a certain high value in a first stage, the temperature of the heating element is decreased to a lower value in a second stage, and the temperature of the heating element is gradually increased in a third stage. This temperature profile flattens the amount of aerosol generated over time to some extent. Patent Document 1 also discloses that, in order to realize this temperature profile, the temperature of the heating element is guided to a target temperature by PID control, which is a typical feedback control. Patent Document 2 discloses a method of temporarily stopping the supply of power to the heating element when decreasing the temperature of the heating element that has been increased once. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-74797 A [Patent Document 2] Special Publication No. 2019-531049 Summary of the Invention [Problem to be solved by the invention]

[0006] However, there is still room for improvement in existing aerosol generating devices with respect to how to control the heating temperature over the heating period. For example, sufficient tracking of the measured temperature with respect to the actual temperature is required in order to measure the temperature and feed it back to the control, but depending on the aspect of temperature control, it is not easy to achieve both the efficiency of temperature control and the tracking of the measured temperature. In addition, the content of temperature control is generally tuned through trial and error during design, but the environmental conditions on the occasion when the aerosol is actually inhaled are not constant, and the properties of the substrate also differ depending on the type. Therefore, if the control cannot be flexibly changed even after tuning is completed once, it will be necessary to apply suboptimal control in situations such as changes in the environment or type. In addition, if the progress of the heating profile is controlled by achieving the target temperature, the timing of progress will vary depending on the conditions, and the early end of the session or, conversely, the decrease in the amount of aerosol generated due to prolonged use may lead to a loss of user experience.

[0007] The techniques disclosed herein seek to at least partially overcome or mitigate the above-mentioned disadvantages and provide improved temperature control for aerosol generation. [Means for solving the problem]

[0008] According to one aspect, an aerosol generating device is provided, comprising: a heating unit that heats an aerosol source to generate an aerosol; a power source that supplies power to the heating unit; a thermistor that outputs a value dependent on the temperature of the heating unit; and a control unit that controls the supply of power from the power source to the heating unit in accordance with a control sequence that includes at least a first interval in which a target value for temperature control of the heating unit is set to a value corresponding to a first temperature and power is supplied from the power source to the heating unit, a second interval following the first interval in which the supply of power from the power source to the heating unit is stopped so that the temperature of the heating unit drops toward a second temperature lower than the first temperature, and a third interval following the second interval in which power is supplied from the power source to the heating unit, wherein the control unit controls the supply of power from the power source in the first interval and the third interval using a first temperature index based on the electrical resistance value of the heating unit, and determines the timing to end the second interval using a second temperature index based on the output value from the thermistor.

[0009] The control unit may terminate the second section when it is determined from the second temperature indicator that the temperature of the heating unit has reached the second temperature.

[0010] The control unit may correct the second temperature index in the second section based on the relationship between the first temperature index and the second temperature index, and use the corrected second temperature index to determine whether the temperature of the heating unit has reached the second temperature.

[0011] The control unit may acquire the first temperature index based on the electrical resistance value of the heating unit and the second temperature index based on the output value from the thermistor in a section preceding the second section, and determine the relationship between the acquired first temperature index and the acquired second temperature index.

[0012] The relationship between the first temperature index and the second temperature index may include a difference in a rate of temperature change between the first temperature index and the second temperature index.

[0013] The control unit may control the supply of power from the power source in the third section using different sets of control parameters depending on the temperature of the heating section indicated by the first temperature indicator when starting the third section.

[0014] The control unit may use a first set of control parameters for restoring the temperature of the heating unit to the second temperature when the temperature of the heating unit at the start of the third section is lower than the second temperature, and may use a second set of control parameters for maintaining the temperature of the heating unit at the third temperature when the temperature of the heating unit at the start of the third section is a third temperature that is higher than or equal to the second temperature.

[0015] The first set of control parameters may include a first value of a proportional gain of feedback control, and the second set of control parameters may include a second value of a proportional gain of feedback control, the first value being greater than the second value.

[0016] The first value of a proportional gain of feedback control included in the first control parameter set may be equal to a value of a proportional gain used during pre-heating of the heating section.

[0017] The control unit may end the second section when a predetermined time has elapsed from the start of the second section, even before the temperature of the heating unit reaches the second temperature.

[0018] According to another aspect, there is provided a method for controlling the generation of aerosol in an aerosol generating device, the method may include process steps corresponding to any combination of the above-mentioned features of the aerosol generating device. Effect of the Invention

[0019] The techniques disclosed herein provide improved temperature control for aerosol generation. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing the appearance of an aerosol generating device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram for explaining the insertion of a tobacco stick into the aerosol generation device of FIG. 1. [Diagram 3] FIG. 2 is a block diagram showing an example of a schematic circuit configuration of the aerosol generating device of FIG. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of a measurement circuit used to measure the temperature of a heating unit. [Diagram 5] FIG. 4 is an explanatory diagram for explaining a measurement period and a PWM control period during a heating period. [Figure 6] FIG. 4 is an explanatory diagram for explaining an example of a positional relationship between a heating unit and a thermistor. [Figure 7] FIG. 4 is an explanatory diagram for explaining a temperature profile and a heating profile according to an embodiment. [Figure 8] FIG. 11 is an explanatory diagram showing an example of a temperature profile in a case where the temperature decreasing section ends earlier than a predetermined time and therefore the remaining time is added to the time length of the subsequent section. [Figure 9] FIG. 4 is an explanatory diagram for explaining the relationship between a first temperature index and a second temperature index. [Figure 10] FIG. 4 is an explanatory diagram showing two examples of temperature profiles when the target temperature of the subsequent section is reset to the temperature at the end of the temperature decreasing section. [Figure 11] FIG. 11 is an explanatory diagram showing an example of a temperature profile in the first modified example in which the subsequent section is shortened because the temperature decreasing section ends later than a predetermined time. [Figure 12] FIG. 11 is an explanatory diagram showing an example of a temperature profile in a case where the subsequent section is shortened because the temperature decreasing section ends later than a predetermined time in the second modified example. [Figure 13] FIG. 11 is an explanatory diagram showing an example of a temperature profile in a case where the end of the temperature decreasing section is delayed significantly from a predetermined time, so that the subsequent section is skipped and the further subsequent section is shortened in the first modified example. [Figure 14]FIG. 11 is an explanatory diagram showing an example of a temperature profile in a case where the end of the temperature decreasing section is delayed significantly from a predetermined time, so that the subsequent section is skipped and the further subsequent section is shortened in the second modified example. [Figure 15] FIG. 13 is an explanatory diagram showing an example of a temperature profile in the case where the target temperature in the temperature maintenance section before the end is reset to the temperature at the reference time point. [Figure 16] FIG. 13 is an explanatory diagram showing an example of a temperature profile including a recovery section according to a third modified example. [Figure 17A] FIG. 4 is an explanatory diagram showing a first example of the configuration of profile data that describes a heating profile. [Figure 17B] FIG. 11 is an explanatory diagram showing a second example of the configuration of profile data that describes a heating profile. [Figure 18] 1 is a flowchart showing an example of an overall flow of an aerosol generation process according to an embodiment. [Figure 19] 20 is a flowchart showing an example of the flow of a temperature control process for a PID control section in FIG. 18 . [Figure 20A] 19 is a flowchart showing a first example of the flow of a temperature control process for the OFF period of FIG. 18. [Figure 20B] 19 is a flowchart showing a second example of the flow of the temperature control process for the OFF period of FIG. 18. [Figure 20C] 19 is a flowchart showing a third example of the flow of a temperature control process for the OFF period of FIG. 18. [Figure 21] 10 is a flowchart showing an example of the flow of a process for determining the end of a preheating temperature increase section. [Figure 22] 11 is a flowchart showing an example of the flow of a process for determining the end of a temperature decreasing section. [Figure 23] 11 is a flowchart showing an example of the flow of a control parameter selection process after the end of a temperature decreasing section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0022] <<1. Device configuration example>> In this specification, the present disclosure will be described mainly as an example of application of the technology to a non-combustion device that generates an aerosol by heating an aerosol source to atomize it without combustion. Such a device may also be called a reduced risk product (RRP) or simply an electronic cigarette. However, the present disclosure is not limited to such an example, and the technology may be applied to any type of aerosol generating device, such as a combustion device or a medical nebulizer.

[0023] <1-1.Appearance> Fig. 1 is a perspective view showing the appearance of an aerosol generation device 10 according to one embodiment. Fig. 2 is an explanatory diagram for explaining the insertion of a tobacco stick into the aerosol generation device 10 shown in Fig. 1. Referring to Fig. 1, the aerosol generation device 10 includes a main body 101, a front panel 102, a display window 103, and a slider 104.

[0024] The main body 101 is a housing that supports one or more circuit boards of the aerosol generating device 10 therein. In this embodiment, the main body 101 has a rounded, approximately rectangular parallelepiped shape that is long in the vertical direction in the figure. The size of the main body 101 may be, for example, a size that a user can hold with one hand. The front panel 102 is a flexible panel member that covers the front surface of the main body 101. The front panel 102 may be detachable from the main body 101. The front panel 102 also functions as an input unit that accepts user input. For example, when a user presses the center of the front panel 102, a button (not shown) disposed between the main body 101 and the front panel 102 is pressed, and the user input can be detected. The display window 103 is a strip-shaped window that extends along the longitudinal direction at approximately the center of the front panel 102. Display window 103 transmits light emitted by one or more LEDs (Light-Emitting Diodes) disposed between main body 101 and front panel 102 to the outside.

[0025] The slider 104 is a cover member disposed on the upper surface of the main body 101 so as to be slidable along a direction 104a. As shown in FIG. 2, when the slider 104 is slid toward the viewer in the figure (i.e., the slider 104 is opened), an opening 106 on the upper surface of the main body 101 is exposed. When a user inhales an aerosol using the aerosol generating device 10, the user inserts a tobacco stick 15 into a tubular insertion hole 107 along a direction 106a from the opening 106 exposed by opening the slider 104. The cross section of the insertion hole 107 perpendicular to the axial direction may be, for example, a circle, an ellipse, or a polygon, and the cross-sectional area gradually decreases toward the bottom surface. As a result, the outer surface of the tobacco stick 15 inserted into the insertion hole 107 is pressed from the inner surface of the insertion hole 107, and the tobacco stick 15 is prevented from falling out by frictional force, and the transfer efficiency of heat from a heating unit 130 to the tobacco stick 15, which will be described later, is improved. When the user finishes inhaling the aerosol, he or she pulls out the tobacco stick 15 from the insertion hole 107 and closes the slider 104.

[0026] The tobacco stick 15 is a tobacco article that holds a filler inside a cylindrical cigarette paper. The filler of the tobacco stick 15 may be, for example, a mixture of an aerosol-generating substrate and tobacco shreds. As the aerosol-generating substrate, a substrate containing any kind of aerosol source, such as glycerin, propylene glycol, triacetin, 1,3-butanediol, or a mixture thereof, may be used. The tobacco shreds are a so-called flavor source. The material of the tobacco shreds may be, for example, lamina or midrib. Note that a flavor source derived from a non-tobacco source may be used instead of the tobacco shreds.

[0027] <1-2. Circuit configuration> Fig. 3 is a block diagram showing an example of a schematic circuit configuration of the aerosol generation device 10. Referring to Fig. 3, the aerosol generation device 10 includes a control unit 120, a storage unit 121, an input detection unit 122, a state detection unit 123, a suction detection unit 124, a light emission unit 125, a vibration unit 126, a communication interface (I / F) 127, a connection I / F 128, a heating unit 130, a first switch 131, a second switch 132, a battery 140, a boost circuit 141, a fuel gauge 142, a measurement circuit 150, and a thermistor 155.

[0028] The control unit 120 may be a processor such as a CPU (Central Processing Unit) or a microcontroller. The control unit 120 controls the overall functions of the aerosol generation device 10 by executing a computer program (also called software or firmware) stored in the storage unit 121. The storage unit 121 may be a semiconductor memory, for example. The storage unit 121 stores one or more computer programs and various data (for example, profile data 51 describing a heating profile 50) used for heating control described later.

[0029] The input detection unit 122 is a detection circuit for detecting a user input. For example, the input detection unit 122 detects a user's pressing of the front panel 102 (i.e., pressing a button) and outputs an input signal indicating the detected state to the control unit 120. Note that the aerosol generation device 10 may include any type of input device, such as a button, a switch, or a touch-sensitive surface, instead of (or in addition to) the front panel 102. The state detection unit 123 is a detection circuit for detecting the open / closed state of the slider 104. The state detection unit 123 outputs a state detection signal indicating whether the slider 104 is open or closed to the control unit 120. The inhalation detection unit 124 is a detection circuit for detecting the inhalation (puff) of the tobacco stick 15 by the user. As an example, the inhalation detection unit 124 may include a thermistor (not shown) disposed near the opening 106. In this case, suction detection unit 124 can detect suction based on a change in the resistance value of the thermistor caused by a temperature change resulting from suction by the user. As another example, suction detection unit 124 may include a pressure sensor (not shown) disposed at the bottom of insertion hole 107. In this case, suction detection unit 124 can detect suction based on a decrease in air pressure caused by an airflow caused by suction. Suction detection unit 124 outputs, for example, a suction detection signal indicating whether suction is being performed to control unit 120.

[0030] The light emitting unit 125 includes one or more LEDs and a driver for driving the LEDs. The light emitting unit 125 causes each of the LEDs to emit light in accordance with an instruction signal input from the control unit 120. The vibration unit 126 includes a vibrator (e.g., an eccentric motor) and a driver for driving the vibrator. The vibration unit 126 causes the vibrator to vibrate in accordance with an instruction signal input from the control unit 120. The control unit 120 may use one or both of the light emitting unit 125 and the vibration unit 126 in an arbitrary pattern, for example, to notify the user of some status of the aerosol generating device 10 (e.g., the progress of a session). For example, the light emitting pattern of the light emitting unit 125 can be distinguished by factors such as the light emitting state (always emitting light / blinking / not emitting light), the blinking cycle, and the light emitting color of each LED. The vibration pattern of the vibration unit 126 can be distinguished by factors such as the vibration state (vibration / stop) and the vibration strength of the vibrator.

[0031] The wireless I / F 127 is a communication interface for wirelessly communicating the aerosol generation device 10 with other devices (e.g., a personal computer (PC) or a smartphone owned by a user). The wireless I / F 127 may be an interface conforming to any wireless communication protocol, such as Bluetooth (registered trademark), near field communication (NFC), or wireless local area network (LAN). The connection I / F 128 is a wired interface having a terminal for connecting the aerosol generation device 10 to other devices. The connection I / F 128 may be, for example, a universal serial bus (USB) interface. The connection I / F 128 may be used to charge the battery 140 from an external power source (via a power supply line not shown).

[0032] The heating unit 130 is a resistive heating component that generates an aerosol by heating the aerosol source contained in the aerosol generating substrate of the tobacco stick 15. For example, one or a mixture of two or more of copper, nickel alloy, chromium alloy, stainless steel, and platinum-rhodium may be used as the resistive heating material of the heating unit 130. One end of the heating unit 130 is connected to the positive electrode of the battery 140 via the first switch 131 and the boost circuit 141, and the other end of the heating unit 130 is connected to the negative electrode of the battery 140 via the second switch 132. The first switch 131 is a switching element provided in the power supply line between the heating unit 130 and the boost circuit 141. The second switch 132 is a switching element provided in the ground line between the heating unit 130 and the battery 140. The first switch 131 and the second switch 132 may be, for example, FETs (Field Effect Transistors).

[0033] The battery 140 is a power source for supplying power to the heating unit 130 and other components of the aerosol generation device 10. In FIG. 3, power supply lines from the battery 140 to components other than the heating unit 130 are omitted. The battery 140 may be, for example, a lithium-ion battery. The boost circuit (DC / DC converter) 141 is a voltage conversion circuit that amplifies the voltage of the battery 140 to supply power to the heating unit 130. The fuel gauge 142 is an IC chip for monitoring the remaining power of the battery 140 and other statuses. The fuel gauge 142 may periodically measure status values ​​of the battery 140, such as the state of charge (SOC), the degree of deterioration (SOH), the relative state of charge (RSOC), and the power supply voltage, and output the measurement results to the control unit 120.

[0034] When a user input requesting the start of heating is detected, the control unit 120 starts supplying power from the battery 140 to the heating unit 130. The user input here may be, for example, a long press of a button detected by the input detection unit 122. The control unit 120 outputs a control signal to the first switch 131 and the second switch 132 to turn on both switches, thereby supplying power from the battery 140 to the heating unit 130 with a voltage amplified by the boost circuit 141. When the first switch 131 and the second switch 132 are FETs, the control signal output from the control unit 120 to both switches is a control pulse applied to each gate. In temperature control described later, the control unit 120 adjusts the duty ratio of this control pulse by pulse width modulation (PWM). The control unit 120 may use pulse frequency modulation (PFM) instead of PWM.

[0035] <1-3. Heater temperature measurement> In this embodiment, the control unit 120 controls the supply of power from the battery 140 to the heating unit 130 so as to realize a desired temperature profile for providing a good user experience throughout the entire heating period including the preheating period and the inhalable period. The control may be mainly feedback control in which a temperature index having a correlation with the temperature of the heating unit 130 is a controlled variable and a duty ratio of PWM is a manipulated variable. Here, PID control is adopted as the feedback control. In this embodiment, the aerosol generating device 10 has two types of measuring units for measuring the temperature index of the heating unit 130. The measuring circuit 150 shown in FIG. 3 is one of the two types of measuring units, and measures a first temperature index based on the electrical resistance value of the heating unit 130. The other measuring unit is a thermistor 155 described later.

[0036] Fig. 4 is a block diagram showing an example of the configuration of the measurement circuit 150 shown in Fig. 3. Referring to Fig. 4, the measurement circuit 150 includes voltage dividing resistors 151, 152, and 153 and an operational amplifier 154. One end of the voltage dividing resistor 151 is connected to a power supply voltage V TEMP, and the other end is connected to one end of a voltage dividing resistor 152. The other end of the voltage dividing resistor 152 is grounded. A junction between the voltage dividing resistors 151 and 152 is connected to a terminal ADC_VTEMP of the control unit 120. An input to the terminal ADC_VTEMP indicates a reference value for measuring resistance values. One end of the voltage dividing resistor 153 is connected to a power supply voltage V TEMP and the other end is connected to the power supply line of the heating unit 130. A junction between the voltage dividing resistor 153 and the power supply line of the heating unit 130 is connected to a first input terminal of an operational amplifier 154. A second input terminal of the operational amplifier 154 is grounded. An output terminal of the operational amplifier 154 is connected to a terminal ADC_HEAT_TEMP of the control unit 120. An input to the terminal ADC_HEAT_TEMP indicates a value that changes depending on an electrical resistance value Rh that depends on the temperature of the heating unit 130. The control unit 120 can calculate the electrical resistance value Rh of the heating unit 130 based on the ratio of the input value to the terminal ADC_HEAT_TEMP to the input value (reference value) to the terminal ADC_VTEMP.

[0037] Here, the electric resistance value of the heating unit 130 has a characteristic that, for example, it increases monotonically as the temperature rises (i.e., it has a correlation with the temperature). Therefore, in this embodiment, the control unit 120 uses the electric resistance value of the heating unit 130 calculated using the measurement circuit 150 as a temperature index (first temperature index) as a control amount of the PID control. Of course, the control unit 120 may further convert the calculated electric resistance value into a temperature using a resistance temperature coefficient, and use the measured temperature derived thereby as a control amount of the PID control.

[0038] <1-4. Temperature control> As described above, in this embodiment, the temperature control of the heating unit 130 is performed by a method in which the duty ratio of the PWM of the power provided to the heating unit 130 is determined mainly by PID control. TGT [Ω] and the index value (measured resistance value) of the first temperature index in the current control cycle n (n is an integer) is R(n) [Ω]. The duty ratio D(n) of the control cycle n can be derived, for example, according to the following formula (1):

number

[0039] In formula (1), K p , K i and K d represent the proportional gain, integral gain, and differential gain, respectively. Note that in the second term on the right side, which is the integral term, saturation control may be applied to the accumulated value of the deviation of the index value from the target value. In this case, if the accumulated value exceeds a predetermined upper limit value, it is replaced with the upper limit value, and if the accumulated value falls below a predetermined lower limit value, it is replaced with the lower limit value.

[0040] In order to enable feedback control during the heating period, in this embodiment, the control unit 120 sets a part of the repeated control cycle as a measurement period for measuring the first temperature index, and sets the remaining control cycle as a PWM control period for performing PWM control. FIG. 5 is an explanatory diagram for explaining the measurement period and PWM control period during the heating period. The horizontal axis in the figure represents time, and the vertical axis represents the voltage applied to the heating unit 130. One control cycle during the heating period consists of an initial measurement period 20 and a remaining PWM control period 30. In the example of FIG. 5, the period from t0 to t1 is the measurement period 20 of one control cycle, and the period from t1 to t2 is the PWM control period 30 of the control cycle. Similarly, the period from t2 to t3 is the measurement period 20 of the next control cycle, and the period from t3 to t4 is the PWM control period 30 of the control cycle. The length of one control cycle corresponds to the period of measurement of the first temperature index, and may be, for example, several tens of milliseconds.

[0041] In the control cycle n, the control unit 120 applies a very short pulse 21 (e.g., a pulse width of 2 ms) to the heating unit 130 multiple times (e.g., 8 times) during the measurement period 20, and sets the average value of the resistance value calculated multiple times using the measurement circuit 150 within one measurement period 20 as the measurement value R(n) of the first temperature index. The control unit 120 uses the measurement value R(n) to calculate the PWM duty ratio D(n) of the control cycle n according to the above control formula. Then, in the PWM control period 30, the control unit 120 applies a pulse 31 having a pulse width W1 corresponding to the product of the length W0 of the period and the duty ratio D(n) to the heating unit 130 (outputting a control pulse having the same pulse width W1 to the first switch 131 and the second switch 132). Through the repetition of such feedback control, the temperature of the heating unit 130 is controlled to approach the target value.

[0042] <1-5. Introduction of auxiliary thermistors> If the measurement period 20 is set periodically throughout the heating period, the above-mentioned control cycle can be repeated. However, the method of applying a pulse to the heating unit 130 during the measurement period 20, even if the pulse width is short, increases the temperature of the heating unit 130 itself and consumes the remaining battery power. On the other hand, the desired temperature profile of the heating unit 130 may include a period in which the temperature of the heating unit 130, which has once been increased to a high value, is decreased to a lower value. During this period, it is advantageous to not apply any pulses to the heating unit 130 in order to efficiently decrease the temperature of the heating unit 130. However, if no pulses are applied to the heating unit 130, the first temperature index cannot be measured using the measurement circuit 150. Therefore, the aerosol generating device 10 according to this embodiment further includes a thermistor 155, as shown in FIG. 3. The thermistor 155 is disposed near the heating unit 130 and outputs a value dependent on the temperature of the heating unit 130 to the control unit 120. In the section in which the temperature of heating unit 130 is decreased, control unit 120 uses a second temperature index based on the output value from thermistor 155 (for example, by comparing the index value with a target value) to determine the timing to end the section. On the other hand, in the other sections, control unit 120 controls the supply of power from battery 140 to heating unit 130 using a first temperature index based on the electrical resistance value of heating unit 130, as described above. The period for measuring the second temperature index may be, for example, several tens to several hundreds of milliseconds.

[0043] FIG. 6 shows an example of the positional relationship between the heating unit 130 and thermistor 155, as viewed from the direction 106a (the axial direction of the insertion hole 107) in FIG. 2. In the example of FIG. 6, the cylindrical member 130a is a member that defines the space of the insertion hole 107 for receiving the tobacco stick 15. The cylindrical member 130a is formed of a material with high thermal conductivity, such as stainless steel (SUS) or aluminum. The film heater 130b is wound around the outer periphery of the cylindrical member 130a. The film heater 130b is made of a pair of films with high heat resistance and insulation properties, and a resistance heating material sandwiched between the films. The heating unit 130 is made of the cylindrical member 130a and the film heater 130b, and Joule heat generated by a current flowing through the film heater 130b heats the tobacco stick 15 inserted into the insertion hole 107 via the cylindrical member 130a. Furthermore, the heat insulating member 108 is wound around the outer periphery of the film heater 130b. The heat insulating member 108 is made of, for example, glass wool, and protects other components of the aerosol generating device 10 from the heat of the heating unit 130. The thermistor 155 is disposed on the outside of the heat insulating member 108. The surface of the film heater 130b is usually smooth, and if the thermistor 155 is disposed on the outer surface of the film heater 130b, positioning tends to be difficult. However, if the thermistor 155 is disposed on the outer surface of the heat insulating member 108 made of glass wool, the positioning of the thermistor 155 becomes easy, and good protection of the control circuit connected to the thermistor 155 is also achieved. However, due to the positional relationship in which the heat insulating member 108 is disposed between the heating unit 130 and thermistor 155, the second temperature indicator based on the output value from the thermistor 155 follows the change in temperature of the heating unit 130 with some delay.

[0044] <1-6. Temperature profile and heating profile> The control unit 120 executes temperature control of the heating unit 130 according to a heating profile, which is a control sequence that defines the temporal transition of control conditions for realizing a desired temperature profile. In this embodiment, the heating profile is made up of a plurality of sections that divide a heating period into time periods, and the temperature control specifications for each section are specified by target values ​​and other control parameters.

[0045] 7 is an explanatory diagram for explaining a temperature profile and a heating profile that can be adopted in this embodiment. In the diagram, the horizontal axis represents the elapsed time from the start of power supply to the heating unit 130, and the vertical axis represents the temperature of the heating unit 130. The thick broken line represents a temperature profile 40 as an example. The temperature profile 40 is made up of an initial preheating period (T0 to T2) and an inhalation possible period (T2 to T8) that follows the preheating period. As an example, the entire inhalation possible period may be about 5 minutes long, and the user can inhale a dozen times during the inhalation possible period.

[0046] The preheating period includes a temperature rise section (T0 to T1) in which the temperature of the heating unit 130 is rapidly raised from the environmental temperature H0 to the first temperature H1, and a temperature maintenance section (T1 to T2) in which the temperature of the heating unit 130 is maintained at the first temperature H1. In this way, by first rapidly heating the heating unit 130 to the first temperature H1, heat can be quickly and sufficiently distributed throughout the aerosol-generating substrate of the tobacco stick 15, making it possible to start providing good quality aerosol to the user sooner.

[0047] The inhalation period includes a maintenance section (T2-T3) in which the temperature of the heating unit 130 is maintained at the first temperature H1, a temperature drop section (T3-T4) in which the temperature of the heating unit 130 is lowered to the second temperature H2, and a maintenance section (T4-T5) in which the temperature of the heating unit 130 is maintained at the second temperature H2. In this way, by lowering the temperature of the heating unit 130, which has once risen to the first temperature H1, to the second temperature H2, it is possible to provide the user with a long and stable inhalation with a suitable smoking taste. The inhalation period further includes a temperature rise section (T5-T6) in which the temperature of the heating unit 130 is gradually raised from the second temperature H2 to the third temperature H3, a maintenance section (T6-T7) in which the temperature of the heating unit 130 is maintained at the third temperature H3, and a temperature drop section (T7-T8) in which the temperature of the heating unit 130 is lowered to the environmental temperature H0. In this way, by increasing the temperature of the heating section 130 again in the latter half of the inhalation period, it is possible to suppress deterioration of the smoking taste in a situation in which the amount of the aerosol source contained in the tobacco stick 15 decreases, and to provide the user with a highly satisfying experience until the end of the inhalation period.

[0048] As an example, the first temperature H1 may be 295° C., the second temperature H2 may be 230° C., and the third temperature H3 may be 260° C. However, different temperature profiles may be designed, for example, depending on the manufacturer's design guidelines, user preferences, or the characteristics of different types of tobacco articles.

[0049] Heating profile 50 consists of eight intervals S0-S7 bounded by T1-T7. However, as will be explained later, the timing of the transition between two intervals does not necessarily coincide with one of the illustrated times T1-T7, but rather depends on the termination conditions specified for each interval. Heating profile 50 defines, for each of intervals S0-S7, one or more of the control parameters listed below: "Segment type" ·“Target temperature” "Target temperature resistance value" "PID control type" ·"gain" "Time length" "Termination conditions"

[0050] The "section type" is a parameter that specifies whether the section is a PID control section or an off section. Here, the PID control section is a section in which the control unit 120 performs PID control based on the first temperature index calculated by using the measurement circuit 150. The off section is a section in which the control unit 120 stops supplying power to the heating unit 130 without performing PID control.

[0051] The "target temperature" is a parameter that specifies the temperature of the heating unit 130 that should be reached at the end of the section. The "target temperature resistance value" is a parameter that specifies the value obtained by converting the "target temperature" value into a resistance value. For example, the target temperature H TGT [℃] is the target temperature resistance value R TGT Can be converted to [Ω]:

number

[0052] In formula (2), H ENV is the reference environmental temperature, α is the temperature resistance coefficient of the resistive heating material of the heating unit 130, R ENV represents the electrical resistance at the reference ambient temperature. ENV , α and R ENV The values ​​of are all measured or derived in a preliminary evaluation test and are stored in the storage unit 121 in advance.

[0053] The "PID control type" is a parameter that specifies whether the target value for a PID control section is to be kept constant at the value of the "target temperature resistance value" throughout the section, or whether the target value is to be changed linearly by linear interpolation. If the "PID control type" is "constant", the control unit 120 performs feedback control while keeping the target value of temperature control constant in the section. If the "PID control type" is "linear interpolation", the control unit 120 performs feedback control while gradually changing the target value of temperature control in the section. The control target value in "linear interpolation" is set to a specific start value (e.g., the current measured value or the target value of the immediately preceding section) at the beginning of the section, and can be raised or lowered substantially linearly (actually, stepwise for each control cycle) to become the "target temperature resistance value" at the end of the section. The "PID control type", together with the "section type", may be considered as a parameter that specifies the control method to be applied to the temperature control of each section.

[0054] "Gain" is the proportional gain K p , integral gain K i , and the differential gain K d It is a set of parameters that specify the value of . Note that if a gain value different from the gain value specified in the preceding interval is specified for a certain PID control interval, the cumulative deviation of the integral term of the feedback control (the second term on the right side of equation (1)) may be reset.

[0055] The "time length" is a parameter that specifies a predefined time length for each section. The "termination condition" is a parameter that specifies a condition for terminating the temperature control for each section (i.e., a condition for transitioning the temperature control to the next section). The "termination condition" may be, for example, any of the following C1, C2, and C3: C1: The passage of time specified by "Duration" C2: Reaching the temperature index to the resistance value specified in "Target temperature resistance value" C3: C1 or C2, whichever comes first The control unit 120 may have an internal timer circuit for determining whether the termination conditions C1 and C3 are met.

[0056] In this embodiment, when determining whether the conditions C2 and C3 in the temperature rise section are satisfied, the control unit 120 determines whether the temperature index is equal to the target value R TGT and a coefficient β (β is a positive number slightly smaller than 1, e.g., β = 0.9975) that represents the allowable deviation. TGT ´(=β·R TGT ) the temperature index may be regarded as having reached the target value. In this way, by setting the end condition of an interval to the reaching of a certain percentage of the target value instead of the target value itself, it is possible to appropriately proceed to the next interval in temperature control even in a situation where the residual deviation from the target value does not become completely zero. Also, the control unit 120 determines whether the temperature index reaches the target value R TGT or the control threshold R TGT The number of measurement periods 20 that exceeded ´ (N COUNT ) and count the counter N COUNT The temperature index may be deemed to have reached the target value when it becomes equal to a judgment threshold M (M is an integer greater than 1, for example, M=3). In this way, by setting the end condition of an interval as the temperature index reaching the threshold multiple times, it is possible to reduce the possibility that temperature control will proceed to the next interval prematurely as a result of an erroneous judgment caused by an error in resistance measurement. This is useful for achieving robust condition judgment in a situation where the measurement circuit 150 may be affected by noise (for example, momentary fluctuations in current value).

[0057] In the next section, a more specific example of the configuration of the heating profile 50 will be described for each section in turn.

[0058] <<2. Heating profile configuration example>> <2-1. Initial temperature rise (S0)> Section S0 is the first section of the heating profile 50. The "section type" of section S0 is a "PID control section", and the "target temperature" is a first temperature H1. The "target temperature resistance value" is a resistance value (hereinafter referred to as R1) corresponding to the first temperature H1. The "PID control type" of section S0 may be "constant", and the "gain" may be a proportional gain K pBy setting a higher value compared to other sections, the time required for heating up is shortened as much as possible. The "end condition" for section S0 is condition C2, specifically, the first temperature index reaching the resistance value R1.

[0059] The control unit 120 may further re-divide the section S0 into a first half section and a second half section, and in the first half section, supply power from the battery 140 to the heating unit 130 at a settable maximum duty ratio regardless of the gain value and the temperature index value. This makes it possible to efficiently shorten the preheating period and promptly start delivery of the aerosol to the user.

[0060] <2-2. Maintaining temperature during preheating (S1)> The "section type" of the section S1 is a "PID control section", and the "target temperature" is the first temperature H1. The "target temperature resistance value" is the resistance value R1 corresponding to the first temperature H1. The "PID control type" of the section S1 may be "constant". Unlike the case of the rapid temperature rise in the section S0, the "gain" of the section S1 may be set to a value that stabilizes the temperature of the heating unit 130 near the first temperature H1 (for example, a proportional gain smaller than the proportional gain specified for the section S0 may be specified for the section S1). The "time length" of the section S1 may be set to a value within a range of several seconds, for example. The "end condition" of the section S1 is condition C1, specifically, the passage of the time indicated by the "time length". The control unit 120 starts a timer at the start of the section S1, and when it determines that the time indicated by the "time length" has passed, it notifies the user of the end of the preheating period. The notification here may be made by one or both of the emission of light from the light emitting unit 125 in a predetermined light emitting pattern and the vibration of the vibration unit 126 in a predetermined vibration pattern. By sensing this notification, the user recognizes that preparations for suction are complete and that suction can be started.

[0061] <2-3. Start of session (S2)> The "section type" of section S2 is a "PID control section" and the "target temperature" is the first temperature H1. The "target temperature resistance value" is the resistance value R1 corresponding to the first temperature H1. The "PID control type" of section S2 may be "constant". The "gain" of section S2 may be the same as that of section S1. The "time length" of section S2 may be set to a value within a range of several seconds to several tens of seconds, for example. The "end condition" of section S2 is condition C1, specifically, the passage of the time indicated by the "time length". When the control unit 120 determines that the time indicated by the "time length" has passed, it ends section S2 and transitions the temperature control to section S3.

[0062] The user usually starts inhaling the aerosol generated by the aerosol generation device 10 from section S2. The control unit 120 may measure one or more of the number of suctions, the frequency of suctions, the suction time per suction, and the cumulative suction time based on the suction detection signal input from the suction detection unit 124, and store the measurement results in the storage unit 121. This measurement may be continued after section S3.

[0063] <2-4. Temperature drop (S3)> The "section type" of the section S3 is an "off section", and the "target temperature" is the second temperature H2. The "target temperature resistance value" is a resistance value (hereinafter, R2) corresponding to the second temperature H2. That is, in the section S3, the control unit 120 stops the supply of power from the battery 140 to the heating unit 130 so that the temperature of the heating unit 130 drops toward the second temperature H2, which is lower than the first temperature H1. Since the section S3 is an off section, the "PID control type" and the "gain" are not set. The "time length" of the section S3 can be set to a value within a range of several tens of seconds, for example. The "end condition" of the section S3 is the condition C3. Specifically, the control unit 120 ends the section S3 when it is determined from the second temperature index based on the output value from the thermistor 155 that the temperature of the heating unit 130 has reached the second temperature H2. However, the control unit 120 ends section S3 when the time indicated by "time length" has elapsed from the start of section S3 even before the temperature of the heating unit 130 reaches the second temperature H2. In other words, the control unit 120 ends section S3 and transitions the temperature control to section S4 when the second temperature index reaches the target value or a predetermined time has elapsed from the start of the section, whichever occurs first.

[0064] Note that the time indicated by the “time length” from the start of the section S3 (for example, T4), if the section S3 ends due to the second temperature index reaching the target value before T4, the total time of the session will be shortened unless the time length of the subsequent sections is changed. The early end of the session may itself cause the user to feel dissatisfied, or may cause the inconvenience of the aerosol source contained in the aerosol-generating substrate not being fully used up. Therefore, when the control unit 120 ends the section S3 before the time at which the time indicated by the "time length" of the section S3 has elapsed, the control unit 120 adds the remaining time until that time to the "time length" specified for the subsequent section (e.g., section S4). FIG. 8 shows a temperature profile 40a in a case where the section S3 ends before the predetermined time, and therefore the remaining time is added to the time length of the subsequent section S4, in comparison with the temperature profile 40 in FIG. 7. In the temperature profile 40a, the temperature of the heating unit 130 reaches the second temperature H2 at T3a prior to T4. As a result, the time length of the section S4 is added by the remaining time (T4-T3a). In particular, during off sections such as section S3, the rate at which the temperature of the heating section 130 drops varies depending on environmental conditions, so adopting such a technique to compensate for the length of the session is beneficial for efficient consumption of the aerosol source and improved user satisfaction.

[0065] <2-5. Correction of the second temperature index> As described above, the second temperature index based on the output value from the thermistor 155 follows the change in temperature of the heating unit 130 with some delay. Therefore, if the control unit 120 were to compare the second temperature index with the target value as it is to determine the end of the section S3, there is a risk that the temperature of the heating unit 130 will have further dropped from the target temperature at the end of the section S3. If the temperature of the heating unit 130 is too low, the amount of aerosol generated from the aerosol-generating substrate will be reduced, and the smoking taste will deteriorate. Therefore, in this embodiment, the control unit 120 corrects the second temperature index in the section S3 so as to compensate for the delay in the change in the second temperature index, and compares the corrected index value with the target value to determine whether the temperature of the heating unit 130 has reached the second temperature H2. To correct the second temperature index, the control unit 120 uses a relationship determined in advance between the first temperature index and the second temperature index. For example, in a section preceding section S3 (e.g., section S0), control unit 120 acquires a second temperature index based on an output value from thermistor 155, in addition to a first temperature index based on an electrical resistance value of heating unit 130. Then, prior to the start of section S3, control unit 120 determines the relationship between the acquired first temperature index and the acquired second temperature index.

[0066] FIG. 9 is an explanatory diagram for explaining the relationship between the first temperature index and the second temperature index. The solid line graph 61 shows an example of a change in the value of the first temperature index over time when the temperature is controlled up to T4 according to the heating profile 50 described with reference to FIG. 7. The dashed-dotted line graph 62 shows an example of a change in the value of the second temperature index over time when the temperature is controlled up to T4 according to the same heating profile 50. As can be seen from a comparison between the two graphs 61 and 62, the first temperature index and the second temperature index draw a substantially linear trajectory, particularly at the beginning of the preheating period (for example, section S0), but the temperature change rate indicated by the second temperature index (slope g2 in the figure) is relatively small compared to the temperature change rate indicated by the first temperature index (slope g1 in the figure), and even if the first temperature index reaches the target value at T1, the second temperature index does not reach the target value. The difference between the second temperature index and the target value gradually decreases from section S1 to section S2 (as heat from heating unit 130 is transferred to thermistor 155 via insulating member 108), but the difference d1 from the target value remains even at T3. When section S3, i.e., the off section, begins at T3, the first temperature index and the second temperature index decrease and again form an approximately linear graph.

[0067] Here, as a simple model, the difference in slope between the two temperature indexes when the temperature of the heating unit 130 is decreasing is assumed to be equal to the difference in slope (g1-g2) between the two temperature indexes when the temperature is increasing (however, the signs are reversed). Then, the control unit 120 can calculate a correction value to be applied to the second temperature index in the section S3 based on the temperature difference d1 indicated by the two indexes at the start of the section S3 and the difference (g1-g2) in the temperature change rate acquired in the section S0. For simplicity of explanation, if the temperature value is used instead of the resistance value to determine the end condition of the section S3, the correction value Δh(t) to be added to the value of the second temperature index when the time t has elapsed from the start of the section S3 can be calculated as follows:

number

[0068] In addition, instead of acquiring the slope g1 of the first temperature index and the slope g2 of the second temperature index separately, the control unit 120 may acquire the difference between the two slopes (g1-g2) by, for example, dividing the difference between the index values ​​at the point in time when the value of the second temperature index reaches a value corresponding to the second temperature H2 (d2 in FIG. 9) by the elapsed time up to that point in time.

[0069] The above-mentioned relationship between the first temperature index and the second temperature index may be acquired before the heating is started, not during the section S0 to section S2 immediately before the section S3, and may be stored in the storage unit 121. As a first example, the relationship between the first temperature index and the second temperature index may be acquired in an evaluation test before the shipment of the aerosol generating device 10. As a second example, the control unit 120 may acquire and record the value of the first temperature index and the value of the second temperature index at the start and end of the section S3 in each session. In this case, the control unit 120 can calculate the above-mentioned correction value Δh(t) of the second temperature index based on the difference in the rate of change of the values ​​of the two temperature indexes recorded in the past, and use the calculation result, in order to determine the end condition of the section S3 of the new session. As a derivation of the second example, the values ​​of the two temperature indexes may be recorded in association with the environmental temperature measured by a temperature sensor, and the control unit 120 may calculate the correction value of the second temperature index based on the record corresponding to the environmental temperature at the time of the new session. The aerosol generating device 10 may have a temperature sensor for measuring the environmental temperature, or may receive environmental temperature data from another device via the wireless I / F 127 or the connection I / F 128.

[0070] As described above, the control unit 120 uses an index value corrected to compensate for the delay in the change of the second temperature index to determine the termination condition, thereby preventing the temperature of the heating unit 130 from exceeding the second temperature H2 and dropping excessively in section S3, thereby preventing a deterioration in the smoking taste.

[0071] <2-6. Maintaining temperature after cooling (S4)> The "section type" of section S4 is a "PID control section". That is, the control unit 120 resumes the supply of power from the battery 140 to the heating unit 130 in response to the transition of the temperature control from section S3 to section S4. The "target temperature" of section S4 is the second temperature H2. The "target temperature resistance value" is the resistance value R2 corresponding to the second temperature H2. The "PID control type" of section S4 may be "constant". The "gain" of section S4 may be the same as that set in sections S1 and S2. The "time length" of section S4 may be set to, for example, several tens of seconds to several minutes. The "end condition" of section S4 is condition C1, specifically, the passage of time indicated by the "time length". When the control unit 120 determines that the time indicated by the "time length" has passed, it ends section S4 and transitions the temperature control to section S5.

[0072] Here, when the section S3 ends due to the passage of the time indicated by the "time length" of the section S3, the temperature of the heating unit 130 at the end of the section S3 may be significantly higher than the second temperature H2. On the other hand, the "gain" of the section S4 has a value tuned for the purpose of maintaining the temperature constant. Therefore, when the target temperature is set to the second temperature H2 in the section S4 and the PID control is resumed, the temperature of the heating unit 130 may exhibit unstable behavior due to the deviation of the temperature at the start of the section S4 from the second temperature H2. Therefore, when the temperature of the heating unit 130 at the end of the section S3 is higher than the second temperature H2, the control unit 120 may treat the temperature at that time as the target temperature of the section S4. That is, the control unit 120 may reset the target temperature resistance value corresponding to the temperature at the end of the section S3 as the target value of the PID control in the section S4. This makes it possible to stabilize the temperature of the heating unit 130 in the section S4. Fig. 10 shows two examples of temperature profiles (temperature profiles 41a and 41b) in the case where the target temperature resistance value corresponding to the temperature at the end of section S3 is reset as the target value of PID control in section S4, in comparison with the temperature profile 40 in Fig. 7. Temperature profile 41a is an example in which temperature H2a at the end of section S3 is lower than the third temperature H3. Temperature profile 41b is an example in which temperature H2b at the end of section S3 is higher than the third temperature H3.

[0073] Although an example in which the "end condition" of the section S3 is the condition C3 has been described above, as a first modified example, the "end condition" of the section S3 may be the condition C2. In this case, the control unit 120 maintains the temperature control of the section S3 until the temperature indicated by the second temperature index reaches the second temperature H2, regardless of the time elapsed from the start of the section S3. This makes it possible to avoid a situation in which the temperature of the heating unit 130 deviates from the second temperature H2 at the start of the section S4. In this modified example, when the temperature of the heating unit 130 reaches the target temperature H2 later than the time at which the "length of time" of the section S3 elapses from the start of the section S3 (for example, T4 in FIG. 7), the control unit 120 may subtract the excess time from the time from the "length of time" of the section S4 (i.e., shorten the section S4). This makes it possible to avoid the overall length of time of the heating period becoming excessively long, and to prevent a deterioration in the smoking taste due to the depletion of the aerosol source. Fig. 11 shows a temperature profile 42 in the first modified example in which section S4 is shortened as a result of lengthening section S3, in comparison with the temperature profile 40 in Fig. 7. In the temperature profile 42, the temperature of the heating unit 130 reaches the second temperature H2 at T4a after T4. As a result, the time length of section S4 is reduced by the excess time (T4a-T4).

[0074] As a second modified example, the "end condition" of the section S3 is the condition C2, and the control unit 120 may reset the target temperature of the section S3 from the second temperature H2 to the third temperature H3 at the time when the time indicated by the "length of time" of the section S3 has elapsed. In this modified example, the control unit 120 may also subtract the excess time from the time when the temperature of the heating unit 130 reaches the target temperature H3 later than the time when the "length of time" of the section S3 elapses (for example, T4 in FIG. 7) from the "length of time" of the section S4 (i.e., shorten the section S4). This makes it possible to prevent the length of time of the entire heating period from being excessively long. FIG. 12 shows a temperature profile 43 in the second modified example in which the section S4 is shortened as a result of the lengthening of the section S3, in comparison with the temperature profile 40 in FIG. 7. In the temperature profile 43, the target temperature is reset to the third temperature H3 at T4, and the temperature of the heating unit 130 reaches the third temperature H3 at T4b. As a result, the time length of section S4 is reduced by the excess time (T4b-T4).

[0075] <2-7. Reheating (S5)> The "section type" of the section S5 is a "PID control section". The "target temperature" of the section S5 is the third temperature H3. The "target temperature resistance value" is a resistance value (hereinafter, R3) corresponding to the third temperature H3. The "PID control type" of the section S5 is a "linear interpolation". That is, the control unit 120 gradually increases the target value of the PID control from the target value of the section S4 (e.g., resistance value R2) to the resistance value R3 from the start to the end of the section. The "gain" of the section S5 may be the same as or different from that set in the section S4. The "time length" of the section S5 may be set to, for example, several tens of seconds to several minutes. The "end condition" of the section S5 is the condition C1. Specifically, when the time indicated by the "time length" has elapsed from the start of the section S5, the control unit 120 ends the section S5 and transitions the temperature control to the section S6.

[0076] In addition, as in the first modified example described in relation to the section S4, when the "end condition" of the section S3 is the condition C2, the end of the section S3 is significantly delayed, and as a result, the excess time to be deducted may become larger than the "time length" predefined for the section S4. Therefore, in this modified example, when the temperature of the heating section 130 reaches the target temperature H2 later than the time at which the total time of the "time length" of the section S3 and the "time length" of the section S4 elapses from the start of the section S3 (for example, T5 in FIG. 7), the control section 120 may deduct the excess time from that time from the "time length" of the section S5 (i.e., shorten the section S5). At this time, the section S4 is skipped. FIG. 13 shows a temperature profile 44 in the first modified example in which the section S4 is skipped and the section S5 is shortened as a result of the lengthening of the section S3, in comparison with the temperature profile 40 in FIG. 7. In the temperature profile 44, the temperature of the heating section 130 reaches the second temperature H2 at T5a after T5. As a result, the time length of section S5 is reduced by the excess time (T5a-T5).

[0077] The method of shortening section S5 shown in Fig. 13 may be combined with the second modified example described in relation to section S4. Fig. 14 shows a temperature profile 45 in the second modified example in which section S4 is skipped and section S5 is shortened as a result of lengthening section S3, in comparison with the temperature profile 40 in Fig. 7. In the temperature profile 45, the temperature of the heating unit 130 reaches the third temperature H3 (which is the reset target temperature) at T5b after T5. As a result, the time length of section S5 is reduced by the excess time (T5b-T5).

[0078] <2-8. Maintaining temperature after reheating (S6)> The "section type" of section S6 is a "PID control section". The "target temperature" of section S6 is the third temperature H3. The "target temperature resistance value" is the resistance value R3 corresponding to the third temperature H3. The "PID control type" of section S6 may be "constant". The "gain" of section S6 may be the same as that set in sections S1, S2, and S4. The "time length" of section S6 may be set to a value within a range of several tens of seconds, for example. The "end condition" of section S6 is condition C1, specifically, the passage of time indicated by the "time length". When the control unit 120 determines that the time indicated by the "time length" has passed, it ends section S6 and transitions the temperature control to section S7.

[0079] As in section S4, the "gain" in section S6 has a value tuned for the purpose of maintaining the temperature constant. Although the target temperature in section S6 is the third temperature H3, if the temperature at the start of section S6 significantly deviates from the third temperature H3, the temperature of the heating unit 130 may exhibit unstable behavior when the target value for section S6 is set to the resistance value R3 and PID control is resumed. Therefore, when the temperature of the heating unit 130 at a certain reference point (e.g., the start point of section S6) significantly deviates from the third temperature H3 (e.g., higher than the third temperature H3), the control unit 120 may treat the temperature at that point as the target temperature for section S6. That is, the control unit 120 may reset the target temperature resistance value corresponding to the current temperature at the reference point as the target value of the PID control in section S6. This makes it possible to stabilize the temperature of the heating unit 130 in section S6. Fig. 15 shows a temperature profile 46 in a case where a target temperature resistance value corresponding to the current temperature at the start of section S6 is reset as a target value of PID control in section S6, in comparison with the temperature profile 40 in Fig. 7. In the temperature profile 46, the target temperature is reset to a current temperature H3a higher than the third temperature at T6, and the temperature of the heating unit 130 is maintained at temperature H3a throughout section S6.

[0080] <2-9.End (S7)> The "section type" of section S7 is an "off section". In section S7, the temperature of the heating unit 130 drops toward the environmental temperature H0. The "target temperature", "target temperature resistance value", and "gain" of section S7 do not need to be set. The "time length" of section S7 can be set to a value within a range of several seconds to several tens of seconds, for example. The "end condition" of section S7 is condition C1, specifically, the passage of time indicated by the "time length". When the control unit 120 determines that the time indicated by the "time length" has passed, it ends the heating period. At the start of section S7, the control unit 120 may notify the user that the end of the inhalation possible period is approaching by emitting light from the light-emitting unit 125 or vibrating the vibration unit 126. Furthermore, the control unit 120 may notify the user that the inhalation possible period has ended at the end of section S7 by emitting light from the light-emitting unit 125 or vibrating the vibration unit 126.

[0081] <2-10. Recovery (S4a) / Maintenance (S4b) after excessive cooling> In the above, an example has been described in which the section S3 is ended and the temperature control is transitioned to the section S4 when the second temperature index reaches the resistance value R2 corresponding to the second temperature H2. In this case, if the second temperature index is corrected with high accuracy, the temperature of the heating unit 130 at the transition to the section S4 should be approximately equal to the second temperature H2. However, in reality, the corrected second temperature index also contains a certain degree of error, and the temperature of the heating unit 130 at the transition to the section S4 may significantly deviate from the second temperature H2 (for example, drop to a lower temperature). Therefore, as a third modified example, the control unit 120 may acquire the first temperature index when starting the section S4, and in the section S4, control the supply of power from the battery 140 to the heating unit 130 using different sets of control parameters depending on the temperature of the heating unit 130 indicated by the acquired first temperature index.

[0082] Here, when starting the section S4, the temperature of the heating unit 130 indicated by the first temperature indicator is H2 C In the third modification, the control unit 120 determines the temperature H2 C is lower than the second temperature H2 (H2 CFor <H2), a first set of control parameters is used to restore (increase) the temperature of the heating unit 130 to the second temperature H2. On the other hand, when the temperature H2 C is equal to or higher than the second temperature H2 (H2 C ≧H2), a second set of control parameters is used to maintain the temperature of the heating unit 130 at the temperature H2 C . For example, the first set of control parameters includes the value K p1 of the proportional gain of the feedback control, and the second set of control parameters includes the value K p2 of the proportional gain of the feedback control, and K p1 is larger than K p2 . In addition to this, the value of one or both of the integral gain and the derivative gain may differ between the first set of control parameters and the second set of control parameters. In this way, by switching the set of control parameters of the feedback control depending on the temperature of the heating unit 130 at the start of the section S4, it is possible to suppress the temperature of the heating unit 130 from deviating from the desired temperature (for example, the second temperature H2) in the middle of the session, and reduce the deterioration of the taste.

[0083] When it is determined that the temperature of the heating unit 130 has been restored to the second temperature H2 by the temperature control using the first set of control parameters, the control unit 120 may switch the set of control parameters from the first set of control parameters to the second set of control parameters. Typically, it is assumed that even if excessive temperature drop of the heating unit 130 due to the error of the corrected second temperature index occurs, the degree thereof is small. Therefore, by switching the set of control parameters to the second set of control parameters after restoring the temperature of the heating unit 130 in a short time, the stability of the temperature of the heating unit 130 in the section S4 can be enhanced.

[0084] FIG. 16 shows an example of a temperature profile when the section S4 includes a recovery section in the third modification. In the example of FIG. 16, the temperature H2 c at the start of the section S4 is lower than the second temperature H2. Therefore, the control unit 120 sets a recovery section S4a at the beginning of the section S4, and a larger proportional gain value K p1A target value of the PID control may be a resistance value R2 corresponding to the second temperature H2. By this PID control, the temperature of the heating unit 130 is restored to the second temperature H2 at T4c. Then, the control unit 120 transitions the temperature control from the recovery section S4a to the maintenance section S4b, and changes the control parameter set for the PID control to a proportional gain value K p2 Thus, the temperature of the heating unit 130 is maintained near the second temperature H2 until the temperature reaches T5.

[0085] The control unit 120 may also perform threshold determination taking into consideration the coefficient β representing the allowable deviation described above when determining whether the first temperature index has reached the target value R2 in the recovery section S4a. Furthermore, the condition for ending the recovery section S4a (transition to the maintenance section S4b) may be that the first temperature index has reached the threshold M times.

[0086] The first control parameter set used in the recovery section S4a may be the same as the control parameter set used during the initial temperature rise of the heating unit 130 in the section S0. For example, the proportional gain value K p1 may be equal to the value of the proportional gain used during the initial temperature rise. In this way, by reusing the control parameter set between sections with similar control objectives (e.g., rapid temperature rise, slow temperature rise, or temperature maintenance), it is possible to avoid the profile data describing the heating profile becoming large-scale, and to save memory resources for storing the data (and communication resources when communicating the data).

[0087] <2-11. Example of profile data configuration> It is useful to define a structured, standardized data format capable of describing the operational specifications for each section of the heating profile 50 described above. The standardized data format makes it easy to change the temperature control content by switching the heating profile 50 in various situations, such as upgrading the operational specifications, changing the type of tobacco article, and selecting a temperature profile according to the user's preferences. Here, several examples of the configuration of the profile data 51 describing such a heating profile 50 will be described.

[0088] Fig. 17A is an explanatory diagram showing a first example of the configuration of profile data 51. Referring to Fig. 17A, the profile data 51 includes seven information elements: an interval number 52, a control method 53, a target temperature 54, a target temperature resistance value 55, a gain 56, a time length 57, and a termination condition 58.

[0089] The section number 52 is a number (identifier) ​​for identifying each section. The control method 53 is an information element that specifies the control method to be applied to the temperature control of each section among a plurality of control methods. Here, the control method 53 corresponds to a combination of the above-mentioned control parameters "section type" and "PID control type," and can take any one of the values ​​"0," "1," and "2." In the example of FIG. 17A, the section S n The control method 53 for the section S indicates a value of "1", which indicates that the control method to be applied to the section S is PID control, and that the control target value should be maintained constant in the section S. n+1 The control method 53 of the section S indicates a value "0", which indicates that the control method to be applied to the section S is to stop the supply of power to the heating unit 130. n+1 Section S is the off section. n+2 The control method 53 indicates a value "2", which indicates that the control method to be applied to the relevant section is PID control, and that the control target value should be changed linearly in the relevant section.

[0090] The target temperature 54 and the target temperature resistance value 55 are information elements that respectively specify the above-mentioned control parameters "target temperature" and "target temperature resistance value." When temperature control is performed using the temperature itself as the controlled variable, the target temperature resistance value 55 may be omitted from the profile data 51. The gain 56 is an information element that specifies the above-mentioned control parameter set "gain." For the off section, the gain 56 may be left blank. The time length 57 and the end condition 58 are information elements that respectively specify the above-mentioned control parameters "time length" and "end condition."

[0091] Fig. 17B is an explanatory diagram showing a second example of the configuration of the profile data 51. Referring to Fig. 17B, the profile data 51 includes a common area 51a and an area by section 51b.

[0092] The common area 51a is a data area in which common information across multiple sections is described. In the example of FIG. 17B, the common area 51a includes three information elements 59a, 59b, and 59c. The information element 59a specifies a number (identifier) ​​for uniquely identifying the control profile described by the profile data. The information element 59b specifies a first gain set K1, and the information element 59c specifies a second gain set K2. The gain set K1 specifies a proportional gain value K p1 , integral gain value K i1 and the differential gain value K d1 and the gain set K2 includes the proportional gain value K p2 , integral gain value K i2 and the differential gain value K d2 Includes.

[0093] The section area 51b is a data area in which information specific to each section is written. In the example of FIG. 17B, the section area 51b includes six information elements: a section number 52, a target temperature 54, a target temperature resistance value 55, a gain 56, a time length 57, and an end condition 58. Here, the control method 53 shown in FIG. 17A is omitted. Instead, a value of the target temperature 54 greater than zero indicates that a PID control method should be applied to that section. Also, a value of the target temperature 54 of zero indicates that that section is an off section. In the example of FIG. 17B, the section S n+1 Since the target temperature 54 is zero, the section S n+1 is an OFF section. In this way, by giving the meaning of two or more control parameters to one information element in the profile data 51, the number of information elements in the profile data 51 can be reduced. Furthermore, the gain 56 does not specify the specific values ​​of three types of gain as in the example of FIG. 17A, but specifies one of the gain sets K1 and K2. For example, in the section S n For the gain set K1, the interval S n+2 and Section S n+3 A gain set K2 is specified for gain 1. In this manner, by allowing one of a limited number of options defined in the common area 51a to be specified in the section-specific area 51b, it is possible to avoid repetition of redundant value definitions and reduce the data size of the profile data 51. In addition to gains, other control parameters such as temperature or resistance values ​​may also be specified by this method using the common area 51a.

[0094] A structured standard data format like the above-mentioned profile data 51 may be allocated to a predetermined data area of ​​the storage unit 121, and the data in the data area may be made rewritable. This makes it possible to change the contents of the temperature control executed by the control unit 120 simply by rewriting the profile data 51, without the need to change the control program. In this case, the control unit 120 only needs to read out the latest contents from the same data area of ​​the storage unit 121 and use them.

[0095] The configuration of the profile data 51 is not limited to the examples shown in Figures 17A and 17B. The profile data 51 may include additional information elements, or some of the information elements shown in the figures may be omitted. For example, the profile data 51 may include one or more of the following as information common across multiple sections: Heating profile name Heating profile version number - Number of sections that make up the heating profile Calibration value to be added to the temperature or resistance value to absorb the manufacturing tolerance of the resistance temperature characteristic of the heating part for each product (can be written based on the test results before the product is shipped)

[0096] The profile data 51 may also include one or more of the following additional information that may be specified for each section: -Whether to determine the duty ratio of the power supply to the heating section by PID control or to use the maximum duty ratio Whether to reset the cumulative deviation of the integral term of the PID control at the start of the interval -Type of abnormality to be detected

[0097] In this specification, an example is mainly described in which power supply to the heating unit 130 is stopped and pulses for measuring temperature or resistance value are not applied to the heating unit 130 in the off section. However, the control method that can be specified by the profile data 51 may include a method in which power supply (for heating) to the heating unit 130 is stopped but pulses for measuring temperature or resistance value can be applied to the heating unit 130. A section in which such a control method is specified may be called an "off section". Furthermore, the profile data 51 may be capable of specifying an end condition other than the above-mentioned conditions C1 to C3 for each section. For example, the end condition that can be specified may include a condition based on the number of detected suctions or the total time of suction.

[0098] Some of the control parameters of the heating profile 50 described in this section may be described in a separate storage area instead of being described in the profile data 51, or may be described in the program code of the control program.

[0099] <<3. Anomaly detection>> The control unit 120 monitors whether there is an abnormality in the operation of the aerosol generation device 10 while performing temperature control according to the heating profile 50 described in the profile data 51. When the control unit 120 detects an abnormality, it stops the supply of power from the battery 140 to the heating unit 130, stores an error code indicating the type of the detected abnormality in the memory unit 121, and notifies the user of the occurrence of the abnormality. Here, several types of abnormalities that can be detected by the control unit 120 in relation to the temperature control of the heating unit 130 will be described.

[0100] <3-1. Measurement circuit malfunction> If a malfunction occurs in the measurement circuit 150 and an accurate temperature index cannot be obtained, the control unit 120 will not recognize the state even if the heating unit 130 becomes excessively hot. To prevent such a situation, the control unit 120 monitors the amount of change in the first temperature index per predetermined time interval while power is being supplied to the heating unit 130 in section S0. Then, when the amount of change in the first temperature index falls below a threshold, the control unit 120 determines that a malfunction may have occurred in the measurement circuit 150, and stops the supply of power from the battery 140 to the heating unit 130. The threshold here may be, for example, a temperature change of 10° C. (a change in resistance value equivalent to 10° C.) during a time interval of 3 seconds.

[0101] <3-2. Preheating failure> If the temperature of the heating unit 130 does not reach a target value (for example, the first temperature H1) even if power is supplied to the heating unit 130 for a sufficient time during the preheating period, there is a possibility that there is a problem with the power supply path from the battery 140 to the heating unit 130, or that there is an abnormality in the environment, such as an abnormally low environmental temperature. In order to detect such a situation and prevent waste of power, the control unit 120 stops the power supply from the battery 140 to the heating unit 130 when it is determined from the first temperature index that the temperature of the heating unit 130 has not reached the target temperature at a time when a predetermined time has elapsed from the start of heating in the section S0. The predetermined time here may be equal to the time length specified by the heating profile 50 for the section S0 (or may be defined separately from the heating profile 50), and may be, for example, 60 seconds.

[0102] <3-3. Overheating (when heating is resumed)> As described above, the second temperature index based on the output value from the thermistor 155 has a delay or a certain degree of error. Therefore, by determining from the first temperature index whether the heating unit 130 is excessively hot at the end of the off-period section S3, the safety of the device can be further improved. Specifically, when a time length specified by the heating profile 50 has elapsed from the start of the period S3 (when transitioning to the period S4), the control unit 120 compares the temperature of the heating unit 130 indicated by the first temperature index with the first temperature H1. Then, when it is determined that the temperature of the heating unit 130 is higher than the first temperature H1, the control unit 120 determines that the heating unit 130 is in an overheated state and ends the temperature control according to the heating profile 50. Note that the detection of overheating based on the first temperature index may be performed not only when heating is resumed, but also periodically in periods other than the off-period.

[0103] <3-4. Overheating (off section)> The control unit 120 may compare the temperature of the heating unit 130 indicated by the second temperature index with the first temperature H1 in the section S3 so that an overheated state of the heating unit 130 can be detected even in the off section. In this case, too, when the control unit 120 determines that the temperature of the heating unit 130 is higher than the first temperature H1, it determines that the heating unit 130 is in an overheated state, and ends the temperature control according to the heating profile 50. This increases the possibility of early detection of an overheated state caused by some kind of malfunction during the off section.

[0104] <<4. Processing flow>> In this section, the flow of the main parts of the control process executed by the control unit 120 of the above-mentioned aerosol generation device 10 will be described with reference to several flowcharts. In the following description, the processing steps will be abbreviated as S (step).

[0105] For the sake of simplicity, the process steps for detecting an abnormality described in the previous section are not shown in each flowchart. The abnormality detection may be performed periodically as part of the normal control routine of the control unit 120, or may be performed at a specific timing such as the start of heating or a transition of a section. A detection circuit separate from the control unit 120 may detect an abnormality and notify the control unit 120 of the detected abnormality (for example, by an interrupt signal).

[0106] <4-1. Aerosol generation and processing> FIG. 18 is a flowchart showing an example of the overall flow of an aerosol generation process according to an embodiment.

[0107] First, in S101, the control unit 120 monitors an input signal from the input detection unit 122 and waits for a user input requesting the start of heating (e.g., pressing and holding a button). When a user input requesting the start of heating is detected, the process proceeds to S103.

[0108] In S103, the control unit 120 checks the state of the aerosol generating device 10 to start heating. The state check here may include any check condition, such as whether the remaining power of the battery 140 is sufficient and whether the front panel 102 has fallen off. If one or more check conditions are not met, heating is not started and the process returns to S101. If all check conditions are met, the process proceeds to S105.

[0109] In S105, control unit 120 reads out profile data 51 from a predetermined storage area in storage unit 121. The subsequent steps S107 to S133 are repeated for each of a plurality of sections included in heating profile 50 described in profile data 51.

[0110] In S107, the control unit 120 determines whether the current section is a PID control section or an OFF section based on the "section type" that specifies the control method to be applied to the current section. If the current section is a PID control section, the process proceeds to S110. On the other hand, if the current section is an OFF section, the process proceeds to S120.

[0111] In S110, the control unit 120 executes a temperature control process for the PID control section so that the temperature of the heating unit 130 becomes the temperature designated for the current section. A more specific flow of the temperature control process executed here will be described later.

[0112] In S120, the control unit 120 executes a temperature control process for the off section so that the temperature of the heating unit 130 decreases toward a temperature designated for the current section. A more specific flow of the temperature control process executed here will be described later.

[0113] When the temperature control process of S110 or S120 ends due to the satisfaction of the end condition, in S131, the control unit 120 determines whether there is a next section in the heating profile 50. If there is a next section in the heating profile 50, in S131, the temperature control transitions to the next section, and the above-mentioned S107 to S133 are repeated with the next section as the current section. If there is no next section, the aerosol generation process of FIG. 18 ends.

[0114] <4-2. Temperature control process in PID control section> FIG. 19 is a flowchart showing an example of the flow of the temperature control process for the PID control section executed in S110 of FIG.

[0115] First, in S111, the control unit 120 acquires the target temperature and time length specified in the heating profile 50 for the current section, and sets the end condition of the current section. For example, if the end condition is condition C1 or C3, the control unit 120 sets the specified time length in a timer and starts the timer. If the end condition is condition C2 or C3, the control unit 120 sets a control threshold value (e.g., a threshold value that takes into account an allowable deviation) to be compared with the first temperature index based on the specified target temperature.

[0116] Next, in S112, the control unit 120 sets PID control parameters for the current section. For example, the control unit 120 sets the target temperature resistance value, the proportional gain, the integral gain, and the differential gain as target values ​​of the PID control to values ​​specified in the heating profile 50 for the current section.

[0117] The subsequent steps S113 to S118 are repeated for each control cycle. First, in S113, the control unit 120 determines whether or not to linearly interpolate the target value of PID control. If "linear interpolation" is specified as the "PID control type" of the heating profile 50 for the current section, the control unit 120 resets the target value of PID control by linear interpolation in S114 so that it changes stepwise for each control cycle. If "constant" is specified as the "PID control type" for the current section, S114 is skipped.

[0118] Next, in S115, the control unit 120 uses the measurement circuit 150 to acquire a first temperature index based on the electrical resistance value of the heating unit 130. The index value acquired here may be, for example, an average value of the results of multiple resistance value measurements, as described with reference to FIG.

[0119] Next, in S116, the control unit 120 determines whether or not the end condition for the current section set in S111 has been satisfied. If it is determined that the end condition for the current section has not been satisfied, the process proceeds to S117.

[0120] In S117, the control unit 120 calculates the PWM duty ratio for the latest control cycle according to the PID control formula described using formula (1). Next, in S118, the control unit 120 outputs a control pulse having a pulse width based on the calculated duty ratio to the first switch 131 and the second switch 132, thereby supplying power from the battery 140 to the heating unit 130.

[0121] When one control cycle ends in this manner, the process proceeds to the next control cycle, and the above-mentioned steps S113 to S118 are repeated. If it is determined in S116 that the end condition for the current section is satisfied, the temperature control process in FIG. 19 ends.

[0122] <4-3. Temperature control process during off period> (1) First Example FIG. 20A is a flowchart showing a first example of the flow of the temperature control process for the OFF period executed in S120 of FIG.

[0123] First, in S121, the control unit 120 acquires the target temperature and time length for the current section specified in the heating profile 50, and sets the end condition for the current section. An example of the setting for each end condition here may be similar to that described in relation to S111 in FIG.

[0124] Next, in S122, control unit 120 obtains a second temperature index based on the output value from thermistor 155. Next, in S123, control unit 120 corrects the value of the second temperature index obtained in S122 using a pre-determined relationship between the first temperature index and the second temperature index so as to compensate for a delay in the change in the value.

[0125] Next, in S124, the control unit 120 determines whether or not the end condition of the current section set in S121 is satisfied based on the value of the second temperature index corrected in S123. If it is determined that the end condition of the current section is not satisfied, the process returns to S122, and the above-mentioned S122 to S124 are repeated. If it is determined that the end condition of the current section is satisfied, the temperature control process of Fig. 20A ends.

[0126] (2) Second Example FIG. 20B is a flowchart showing a second example of the flow of the temperature control process for the OFF period executed in S120 of FIG.

[0127] Since S121 to S124 in FIG. 20B may be the same processing steps as S121 to S124 in FIG. 20A, the description thereof will be omitted here.

[0128] If it is determined in S124 that the end condition of the current section is satisfied, the control unit 120 determines in S125 whether the current section will end earlier than a predetermined time. The predetermined time here is the time when the time length acquired in S121 has elapsed from the start time of the current section. If the current section will end earlier than the predetermined time, the control unit 120 adds the remaining time until the predetermined time to the time length specified by the heating profile 50 for the section following the current section in S126.

[0129] If it is determined in S125 that the current interval will not end earlier than the predetermined time (will end at the predetermined time), the time length of the subsequent interval is not changed and the temperature control process in FIG. 20B ends.

[0130] (3) Third Example FIG. 20C is a flowchart showing a third example of the flow of the temperature control process for the OFF period executed in S120 of FIG.

[0131] S121 to S126 in FIG. 20C may be the same processing steps as S121 to S126 in FIG. 20B, except that if it is determined in S125 that the current section will not end before the specified time, processing proceeds to S127, and therefore their description will be omitted here.

[0132] In S127, the control unit 120 determines whether the current section ends later than the predetermined time. If the current section ends later than the predetermined time, the control unit 120 subtracts the excess time from the predetermined time from the time length specified by the heating profile 50 for the section following the current section in S128.

[0133] If it is determined in S127 that the current interval will not end later than the predetermined time (will end at the predetermined time), the time length of the subsequent interval is not changed and the temperature control process in FIG. 20C ends.

[0134] In addition, in S128, if the time length specified by the heating profile 50 for the subsequent section is shorter than the excess time from the above-mentioned specified time, the control unit 120 may skip the temperature control of the subsequent section and subtract time from the time length specified for the next section.

[0135] <4-4. End judgment process (section S0)> Fig. 21 is a flowchart showing an example of the flow of the end determination process that can be applied to the section S0 and corresponds to S116 in Fig. 19. In the above-mentioned third modified example, the end determination process shown in Fig. 21 may be applied to the recovery section S4a.

[0136] First, in S141, the control unit 120 obtains a control threshold value equal to the product of the target value of the temperature control for the current section and a coefficient representing the allowable deviation. Note that this processing step needs to be performed only once at the beginning of each section.

[0137] Next, in S142, the control unit 120 determines whether or not the index value of the first temperature index exceeds the control threshold acquired in S141. If the index value of the first temperature index exceeds the judgment threshold, the process proceeds to S143. On the other hand, if the index value of the first temperature index does not exceed the judgment threshold, the process proceeds to S145.

[0138] In S143, the control unit 120 starts a counter N COUNT Add (increment) 1 to the counter N COUNT is initialized to zero at the beginning of each interval. Next, in S144, the control unit 120 increments the counter N COUNT It is judged whether the counter N COUNT When the counter N reaches the determination threshold M, the process proceeds to S146. COUNT If does not reach the determination threshold M, the process proceeds to S145.

[0139] In S145, the control unit 120 determines that the end condition for the current section has not yet been satisfied. On the other hand, in S146, the control unit 120 determines that the end condition for the current section has been satisfied. Then, the end determination process in FIG. 21 ends.

[0140] <4-5. End judgment process (section S3)> FIG. 22 is a flowchart showing an example of the flow of the end determination process that can be applied to section S3 and corresponds to S124 in FIG. 20A or 20B.

[0141] First, in S151, the control unit 120 acquires the current value of the timer that was started at the start of the current section. Next, in S152, the control unit 120 determines whether or not a predetermined time has elapsed since the start of the current section based on the acquired timer value. The length of the predetermined time here may be the time length specified by the heating profile 50 for the current section. If it is determined that the predetermined time has elapsed, the process proceeds to S157. On the other hand, if it is determined that the predetermined time has not elapsed, the process proceeds to S153.

[0142] In S153, the control unit 120 determines whether the index value of the corrected second temperature index has reached the target value. If the corrected index value has reached the target value, the process proceeds to S154. On the other hand, if the corrected index value has not reached the target value, the process proceeds to S156.

[0143] In S154, the control unit 120 counts up the counter N COUNT Next, in S155, the control unit 120 increments the counter N COUNT It is judged whether the counter N COUNT When the counter N reaches the determination threshold M, the process proceeds to S157. COUNT If does not reach the determination threshold M, the process proceeds to S156.

[0144] In S156, the control unit 120 determines that the end condition for the current section has not yet been satisfied. On the other hand, in S157, the control unit 120 determines that the end condition for the current section has been satisfied. Then, the end determination process in FIG. 22 ends.

[0145] <4-6. Control parameter selection process (section S4)> FIG. 23 is a flowchart showing an example of the flow of a control parameter selection process that can be executed at the beginning of section S4 (eg, S112 in FIG. 19) in the above-mentioned third modified example.

[0146] First, in S161, the control unit 120 uses the measurement circuit 150 to obtain a first temperature index based on the electrical resistance value of the heating unit 130. Next, in S162, the control unit 120 obtains a control threshold value equal to the product of the target value of the temperature control for the current section and a coefficient representing the allowable deviation.

[0147] Next, in S163, the control unit 120 determines whether the index value of the first temperature index is equal to or greater than the control threshold. If the index value of the first temperature index is below the control threshold, in S164, the control unit 120 sets the control parameters for the PID control of the current section based on a first control parameter set for restoring the temperature of the heating unit 130. On the other hand, if the index value of the first temperature index is equal to or greater than the control threshold, in S165, the control unit 120 sets the control parameters for the PID control of the current section based on a second control parameter set for maintaining the temperature of the heating unit 130. At this time, the control unit 120 may reset the target value of the temperature control of the current section to the current temperature of the heating unit 130.

[0148] <<5. Summary>> Various embodiments and modifications of the present disclosure have been described above with reference to Figs. 1 to 23. A heating unit that heats the aerosol source to generate an aerosol; A power source for supplying power to the heating unit; a thermistor that outputs a value that depends on the temperature of the heating portion; The supply of power from the power source to the heating unit, a first section in which a target value of the temperature control of the heating unit is set to a value corresponding to a first temperature and power is supplied from the power source to the heating unit; a second interval following the first interval, in which the supply of power from the power source to the heating unit is stopped so that the temperature of the heating unit decreases toward a second temperature lower than the first temperature; and a third section following the second section, in which power is supplied from the power source to the heating section; A control unit that performs control according to a control sequence including at least Equipped with The control unit is In the first section and the third section, a supply of power from the power source is controlled using a first temperature index based on an electrical resistance value of the heating unit; The control unit determines the timing to end the second interval by using a second temperature index based on an output value from the thermistor.

[0149] According to this configuration, in the second section in which the temperature of the heating section is decreased toward the second temperature, it is not necessary to apply a pulse to the heating section for temperature measurement, and the supply of power from the power source to the heating section can be completely stopped to efficiently bring the temperature of the heating section to the second temperature. Since the arrival of the target temperature in the second section is determined based on the output value from the thermistor, the timing of the transition from the second section to the third section is not missed even if a pulse is not applied to the heating section. In addition, in the section in which heating is not stopped, the supply of power is controlled using a temperature index based on the electrical resistance value of the heating section, so that the tracking of the measured temperature to the actual temperature can be maintained well for temperature control.

[0150] An aerosol generating apparatus according to another embodiment of the present disclosure includes: A heating unit that heats the aerosol source to generate an aerosol; A power source for supplying power to the heating unit; A control unit that controls the supply of power from the power source to the heating unit using a temperature index related to a temperature of the heating unit in accordance with a control sequence consisting of a plurality of sections; Equipped with The control sequence is described by structured data including a first information element that specifies a control method to be applied to the temperature control of each section among a plurality of control methods, The plurality of control methods include a first method of performing feedback control using the temperature index, and a second method of stopping the supply of power from the power source to the heating unit.

[0151] With this configuration, even after the temperature control content has been tuned, it is possible to flexibly change when each control method is applied to the temperature control by rewriting the content of the control sequence. This makes it possible to suppress increases in costs due to trial and error when designing the control sequence, and also makes it easy to switch the content of the temperature control to the optimal one when the environment changes or the type of tobacco product is changed.

[0152] According to yet another embodiment of the present disclosure, an aerosol generating apparatus includes: A heating unit that heats the aerosol source to generate an aerosol; A power source for supplying power to the heating unit; The supply of power from the power source to the heating unit, a first section for changing the temperature of the heating section from a first temperature to a second temperature, and a second section following the first section for maintaining the temperature of the heating section; A control unit that performs control according to a control sequence consisting of a plurality of sections including Equipped with the control sequence specifies a first duration for the first section and a second duration for the second section; the control unit ends the first section when the temperature of the heating unit reaches the second temperature; When the control unit ends the first section earlier than a first time at which the first length of time has elapsed since the start of the first section, the control unit continues the second section for the sum of the remaining time until the first time and the second length of time.

[0153] According to this configuration, even if it takes a time shorter than the first time length to change the temperature of the heating unit to the second temperature in the first section, the time during which the user can enjoy inhalation is compensated for by the remaining time of the first section. Therefore, it is possible to avoid a situation in which the user experience is impaired due to an early end of the session while maintaining appropriate temperature control.

[0154] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A resistive heating unit that heats the aerosol source to generate an aerosol; A power source that supplies power to the heating unit; a thermistor that outputs a value that depends on the temperature of the heating portion; Supplying power from the power source to the heating unit, a first section in which a target value of the temperature control of the heating unit is set to a value corresponding to a first temperature and power is supplied from the power source to the heating unit; a second section following the first section, in which the supply of power from the power source to the heating section is stopped so that the temperature of the heating section decreases toward a second temperature lower than the first temperature; and a third section following the second section, in which power is supplied from the power source to the heating section; A control unit that performs control according to a control sequence including at least Equipped with The control unit is In the first section and the third section, a supply of power from the power source is controlled using a first temperature index based on an electrical resistance value of the heating unit; determining a timing to end the second section using a second temperature index based on an output value from the thermistor; Aerosol generating device.

2. The aerosol generating device according to claim 1 , wherein the control unit terminates the second section when it is determined from the second temperature indicator that the temperature of the heating unit has reached the second temperature.

3. The aerosol generating device of claim 2, wherein the control unit corrects the second temperature index in the second section based on the relationship between the first temperature index and the second temperature index, and uses the corrected second temperature index to determine whether the temperature of the heating unit has reached the second temperature.

4. The control unit is In a section preceding the second section, the first temperature index based on the electrical resistance value of the heating section and the second temperature index based on the output value from the thermistor are obtained; determining the relationship between the acquired first temperature indicator and the acquired second temperature indicator; The aerosol generating device according to claim 3 .

5. 5. The aerosol generating device of claim 3 or 4, wherein the relationship between the first temperature indicator and the second temperature indicator comprises a difference in a rate of temperature change between the first temperature indicator and the second temperature indicator.

6. An aerosol generating device as described in any one of claims 1 to 5, wherein the control unit controls the supply of power from the power source in the third section using different sets of control parameters depending on the temperature of the heating section indicated by the first temperature indicator when starting the third section.

7. The control unit is When the temperature of the heating unit at the start of the third period is lower than the second temperature, a first set of control parameters is used to restore the temperature of the heating unit to the second temperature; when the temperature of the heating unit at the start of the third section is a third temperature that is equal to or higher than the second temperature, a second set of control parameters is used to maintain the temperature of the heating unit at the third temperature. The aerosol generating device according to claim 6.

8. the first set of control parameters includes a first value of a proportional gain of a feedback control; the second set of control parameters includes a second value of a proportional gain of a feedback control; the first value is greater than the second value; The aerosol generating device according to claim 7.

9. The aerosol generating device according to claim 8 , wherein the first value of the proportional gain of the feedback control included in the first set of control parameters is equal to a value of the proportional gain used when preheating the heating section.

10. The aerosol generating device according to any one of claims 1 to 9, wherein the control unit terminates the second section when a predetermined time has elapsed from the start of the second section, even before the temperature of the heating unit reaches the second temperature.

11. 1. A method for controlling generation of an aerosol in an aerosol generating device, comprising: The aerosol generating device includes a resistive heating unit that heats an aerosol source to generate an aerosol, a power source that supplies power to the heating unit, and a thermistor that outputs a value that depends on the temperature of the heating unit; The control method includes: In a first section of a control sequence, a target value of temperature control of the heating unit is set to a value corresponding to a first temperature, and power is supplied from the power source to the heating unit; in a second interval following the first interval, stopping the supply of power from the power source to the heating unit so that the temperature of the heating unit decreases toward a second temperature lower than the first temperature; In a third section following the second section, power is supplied from the power source to the heating unit; Including, The control method includes: controlling the supply of power from the power source using a first temperature index based on an electrical resistance value of the heating unit in the first section and the third section; determining a timing to end the second section using a second temperature index based on an output value from the thermistor; The control method further comprises:

12. The control method includes: ending the second section when it is determined from the second temperature indicator that the temperature of the heating unit has reached the second temperature; The control method of claim 11 , further comprising:

13. The control method includes: correcting the second temperature index in the second section based on a relationship between the first temperature index and the second temperature index; Further comprising: The determination as to whether the temperature of the heating unit has reached the second temperature is performed using the corrected second temperature index. The control method according to claim 12.

14. The control method includes: acquiring the first temperature indicator based on the electrical resistance value of the heating unit and the second temperature indicator based on the output value from the thermistor in a section preceding the second section; determining the relationship between the acquired first temperature indicator and the acquired second temperature indicator; The control method of claim 13 further comprising:

15. 15. The method of claim 13 or 14, wherein the relationship between the first temperature index and the second temperature index comprises a difference in a rate of temperature change between the first temperature index and the second temperature index.

16. Controlling the supply of power from the power source in the third section includes: using different sets of control parameters depending on the temperature of the heating section indicated by the first temperature indicator when starting the third section; The control method according to any one of claims 11 to 15, comprising:

17. When the temperature of the heating unit at the start of the third period is lower than the second temperature, a first set of control parameters is used to restore the temperature of the heating unit to the second temperature in the third period; When the temperature of the heating unit at the start of the third section is a third temperature that is equal to or higher than the second temperature, a second set of control parameters is used for maintaining the temperature of the heating unit at the third temperature in the third section.

17. The control method according to claim 16.

18. the first set of control parameters includes a first value of a proportional gain of a feedback control; the second set of control parameters includes a second value of a proportional gain of a feedback control; the first value is greater than the second value; 20. The control method according to claim 17.

19. 20. The control method according to claim 18, wherein the first value of a proportional gain of feedback control included in the first set of control parameters is equal to a value of a proportional gain used during preheating of the heating section.

20. The control method includes: terminating the second section when a predetermined time has elapsed from the start of the second section before the temperature of the heating unit reaches the second temperature; The control method according to any one of claims 11 to 19, further comprising:

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