Electric work machine and motor control method

Abstract

The invention provides an electric working machine and a motor control method. The electric working machine according to one embodiment of the present invention is provided with a motor, a drive circuit, and a control circuit. The control circuit includes a physical quantity acquisition unit, a change amount derivation unit, a sum value calculation unit, and a drive control unit. The physical quantity acquisition unit acquires a physical quantity at each detection timing. The change amount deriving unit derives a change amount of the physical quantity at each of the detection timings. The sum value calculation unit calculates a sum value at each of the detection timings. The sum value corresponds to the sum of the one or more variations. The drive control unit controls the motor by means of the drive circuit according to a first control method on the basis that the sum value satisfies a no-load detection requirement.

Description

Technical Field

[0001] The present invention relates to a technology for controlling a motor of an electric working machine. Background Art

[0002] Japanese Patent No. 6154242 discloses an electric machine that is configured to perform soft no-load control. In the soft no-load control, the output of the motor is suppressed from the start of the motor driving to the detection of the motor load state. When the motor load state is detected, the soft no-load control is released. Summary of the invention

[0003] After the soft no-load control is released, the motor may change from a loaded state to a no-load state. For example, it is assumed that the electric mechanical device is configured to be able to cut the workpiece using a saw blade. In this case, the saw blade that cuts the workpiece temporarily leaves the workpiece, which may cause the motor to change from a loaded state to a no-load state.

[0004] When the motor changes from a loaded state to an unloaded state, if the motor is appropriately controlled according to the change (for example, soft no-load control is performed again), the convenience of the electric machine device is improved. Therefore, it is desirable to detect the unloaded state of the motor with good accuracy.

[0005] One aspect of the present invention is to provide an electric working machine capable of accurately detecting a no-load state of a motor.

[0006] One aspect of the present invention is to provide an electric working machine including a motor, a drive circuit, and a control circuit.

[0007] The motor is configured to drive a driven tool mounted on the electric working machine. The drive circuit is configured to drive the motor. The control circuit includes a physical quantity acquisition unit, a change amount derivation unit, a total value calculation unit, and a drive control unit.

[0008] The physical quantity acquisition unit acquires a physical quantity at each detection timing. The physical quantity is associated with an operating state of the motor.

[0009] The change amount deriving unit derives the change amount at each detection timing. The change amount corresponds to the increase from the previous physical amount to the current physical amount. The previous physical amount corresponds to the physical amount obtained at the previous detection timing. The current physical amount corresponds to the physical amount obtained at the current detection timing.

[0010] The total value calculation unit calculates the total value at each detection timing. The total value corresponds to the sum of one or more changes. The one or more changes correspond to the changes derived at each detection timing in the first period. The first period is a period from the first calculation start timing to the current detection timing.

[0011] The drive control unit controls the motor according to a first control method via the drive circuit based on whether the total value calculated by the total value calculation unit satisfies or has satisfied a no-load detection requirement. The no-load detection requirement is required to detect that no load is applied to the motor.

[0012] The sum value satisfying the no-load detection requirement corresponds to the motor being in a no-load state. The no-load state corresponds to a state in which the load is not applied to the motor. The no-load state includes a state in which the load is not applied to the motor at all. The no-load state may also include a state in which the load of a specified magnitude or less is applied to the motor.

[0013] In the electric working machine configured in this way, it is detected that the motor is in the no-load state based on the total value of the change amounts. Therefore, it is possible to accurately detect that the motor is in the no-load state.

[0014] Another aspect of the present invention relates to a motor control method used in an electric working machine.

[0015] The motor control method comprises the following steps:

[0016] acquiring a physical quantity at each detection timing, the physical quantity being associated with an operating state of a motor provided in the electric working machine;

[0017] deriving a change amount at each detection timing, the change amount corresponding to an increase from a previous physical quantity to a current physical quantity, the previous physical quantity corresponding to the physical quantity acquired at the previous detection timing, and the current physical quantity corresponding to the physical quantity acquired at the current detection timing;

[0018] calculating a total value at each of the detection timings, the total value corresponding to a sum of one or more variation amounts, the one or more variation amounts respectively corresponding to the variation amounts derived at each of the detection timings in the first period; and

[0019] The motor is controlled according to a control method corresponding to the sum value.

[0020] Such a method can produce the same effects as those of the above-mentioned electric working machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a perspective view of the electric working machine according to the embodiment.

[0022] Figure 2 This is a block diagram showing the electrical structure of the electric working machine.

[0023] Figure 3 It is an explanatory diagram showing a first operation example of the electric working machine.

[0024] Figure 4 It is an explanatory diagram showing a second operation example of the electric working machine.

[0025] Figure 5 This is the main processing flow chart.

[0026] Figure 6 It is part of the flowchart of the soft no-load recovery determination process.

[0027] Figure 7 This is the remainder of the flowchart of the soft no-load recovery determination process.

[0028] Figure 8 : is a flowchart of the target rotation speed determination process. DETAILED DESCRIPTION

[0029] [1. Overview of Implementation Methods]

[0030] One embodiment can provide an electric working machine including at least any one of the following features 1 to 6.

[0031] · Feature 1: Motor. The motor may be configured to drive a driven tool attached to the electric working machine. The driven tool may be configured to be detachably attached to the electric working machine.

[0032] Feature 2: A drive circuit is configured to drive the motor.

[0033] Feature 3: A physical quantity acquisition unit configured to acquire a physical quantity at each detection timing. The physical quantity may be associated with an operating state of the motor.

[0034] Feature 4: A change amount deriving unit configured to derive a change amount at each detection timing. The change amount corresponds to an increase (or degree of change) from a previous physical amount to a current physical amount. The current physical amount corresponds to the physical amount acquired at the current detection timing. The previous physical amount may correspond to the physical amount acquired at the previous detection timing. The previous detection timing may be the detection timing immediately before the current detection timing.

[0035] Feature 5: A total value calculation unit is configured to calculate a total value at each detection timing (i.e., whenever the detection timing arrives). The total value corresponds to the sum of one or more changes. The one or more changes correspond to the changes derived at each of the detection timings in the first period. The first period may be a period from the first calculation start timing to the current detection timing (i.e., until the current detection timing arrives).

[0036] Feature 6: A drive control unit configured to control the motor according to a first control method via the drive circuit based on the fact that the total value calculated by the total value calculation unit satisfies or has satisfied a no-load detection requirement. The no-load detection requirement is required to detect that no load is applied to the motor.

[0037] The electric working machine may include a control circuit. The control circuit may include at least one of the physical quantity acquisition unit (i.e., the feature 3), the change amount derivation unit (i.e., the feature 4), the total value calculation unit (i.e., the feature 5), and the drive control unit (i.e., the feature 6).

[0038] The drive circuit may drive the motor by supplying electric power to the motor. The detection timing may be repeated periodically or non-periodically.

[0039] The electric working machine may be equipped with the driven tool, or may be configured to be detachably equipped with the driven tool. The electric working machine may include a transmission mechanism. The transmission mechanism may be configured to transmit the rotational force of the motor to the driven tool.

[0040] In the following description, a state in which the load is not applied to the motor is referred to as a "no-load state", and a state in which the load is applied to the motor is referred to as a "load state". The no-load state includes a state in which the magnitude of the load applied to the motor is zero. In this case, the load state may include a state in which the magnitude of the load applied to the motor is greater than zero. The no-load state may include a state in which the magnitude of the load applied to the motor is less than a prescribed magnitude. In this case, the load state may also include a state in which the magnitude of the load applied to the motor is greater than the prescribed magnitude.

[0041] The fact that the sum value satisfies the no-load detection requirement may correspond to the motor being in the no-load state. The fact that the sum value does not satisfy the no-load detection requirement may correspond to the motor being in the loaded state.

[0042] The load may be applied to the motor from an object of operation outside the electric working machine via the driven tool. The no-load state may include a state in which the driven tool is not in contact with an object (e.g., an object of operation) outside the electric working machine. The no-load state may also include a state in which (i) the driven tool is in contact with the object and (ii) the load of less than the specified magnitude is applied to the motor via the object.

[0043] In the case where the current physical quantity is greater than the previous physical quantity, the change amount (i.e., the increase amount) may be positive. In the case where the current physical quantity is less than the previous physical quantity, the change amount (i.e., the increase amount) may be negative. The change amount may, for example, be a value obtained by subtracting the previous physical quantity from the current physical quantity (i.e., a subtraction value). In other words, the change amount may be the difference between the previous physical quantity and the current physical quantity.

[0044] The change amount may be an amount indicating the level of the subtraction value. Specifically, for example, when (i) the subtraction value (or the change amount) is positive and (ii) the absolute value of the subtraction value is less than a1, "+A" (A is a natural number) may be derived as the change amount. In addition, for example, when (i) the subtraction value (or the change amount) is positive and (ii) the absolute value of the subtraction value is greater than a1, "+2·A" (i.e., 2 times +A) may be derived as the change amount. In addition, for example, when (i) the subtraction value (or the change amount) is negative and (ii) the absolute value of the subtraction value is less than a1, "-A" may be derived as the change amount. In addition, for example, when (i) the subtraction value (or the change amount) is negative and (ii) the absolute value of the subtraction value is greater than a1, "-2·A" (i.e., 2 times -A) may be derived as the change amount.

[0045] A value (or amount) indicating a tendency of change (i.e., increase or decrease) of the physical quantity can be derived as the change amount. Specifically, for example, when the physical quantity increases, the change amount can be derived as "+A". In addition, for example, when the physical quantity decreases, the change amount can be derived as "-A". In this specification, "amount" is a concept that includes "value".

[0046] The first calculation start timing may be arbitrarily determined. The first calculation start timing may be, for example, a predetermined timing after the load state of the motor is determined. The first calculation start timing may be, for example, a predetermined timing after (i) the load state of the motor is determined and (ii) the target reaching timing described later.

[0047] In the electric working machine having at least features 1 to 6, the no-load state of the motor is detected based on the sum value. Thus, the no-load state (or the change from the loaded state to the no-load state) can be detected with good accuracy. In addition, the motor can be controlled based on the first control method at an appropriate timing corresponding to the load.

[0048] A certain embodiment may include at least one of the following features 7 to 10 in addition to or instead of at least one of the features 1 to 6 described above.

[0049] Feature 7: The at least one switch is manually operated by a user of the electric working machine.

[0050] Feature 8: A target setting unit configured to set a target rotation speed of the motor based on the state of the at least one switch. The control circuit described above may include the target setting unit.

[0051] Feature 9: The drive control unit is configured to control the motor according to a second control method based on the fact that the total value does not satisfy the no-load detection requirement. The second control method is different from the first control method.

[0052] Feature 10: The second control method includes controlling the motor so that the motor rotates at the target rotation speed set by the target setting unit.

[0053] In the electric working machine having at least features 1 to 10, the motor can be appropriately controlled when the motor is in the loaded state and when the motor is in the unloaded state.

[0054] A certain embodiment may include the following feature 11 in addition to or instead of at least any one of the features 1 to 10 described above.

[0055] Feature 11: The total value calculation unit is configured to exclude the change amount derived by the change amount deriving unit in a second period from calculation of the total value based on the target rotation speed being changed by the at least one switch. The second period corresponds to a period from a speed change timing to a predetermined timing. The speed change timing corresponds to a timing at which the target rotation speed is changed.

[0056] The physical quantity may change according to the change of the target rotation speed. Therefore, when the target rotation speed changes, the no-load detection requirement may be satisfied even though the motor is not in the no-load state. In other words, even though the motor is not in the no-load state, it may be erroneously determined to be in the no-load state, and the control method of the motor may be switched to the first control method.

[0057] In contrast, in the electric working machine having at least features 1 to 11, when the target rotation speed is changed, the change amount derived in the second period is not included in the total value. Therefore, it is possible to suppress erroneous detection of the no-load state.

[0058] During the second period, the physical quantity acquisition unit and / or the change amount derivation unit may stop operating. When the physical quantity acquisition unit stops operating during the second period, the change amount derivation unit may not derive the change amount or set the change amount to a predetermined amount (e.g., zero) at the first detection timing after the second period.

[0059] A certain embodiment may include at least one of the following features 12 and 13 in addition to or instead of at least one of the features 1 to 11 described above.

[0060] Feature 12: The total value calculation unit is configured to switch the start time of the first period from the first calculation start timing to the second calculation start timing based on the target rotation speed being changed by the at least one switch.

[0061] Feature 13: The second calculation start timing corresponds to the predetermined timing (that is, the end time of the second period).

[0062] In the electric working machine having at least features 1 to 13, the no-load detection requirement is determined based on the sum of the changes from the second calculation start timing. Therefore, the changes in the second period can be easily excluded from calculation of the sum value.

[0063] A certain embodiment may include at least one of the following features 14 to 16 in addition to or instead of at least one of the features 1 to 13 described above.

[0064] Feature 14: A control rotational speed setting unit configured to (i) set a control rotational speed based on the target rotational speed and (ii) gradually change the control rotational speed to the changed target rotational speed based on a change in the target rotational speed. The control rotational speed setting unit may be provided in the control circuit.

[0065] Feature 15: The second control method includes controlling the motor so that an actual rotation speed of the motor coincides with the controlled rotation speed.

[0066] Feature 16: The second period includes a target reaching period. The target reaching period corresponds to a period from the speed change timing to the target reaching timing. The target reaching timing corresponds to a timing when the control rotation speed reaches the target rotation speed by the control rotation speed setting unit.

[0067] The control rotational speed setting unit can basically make the control rotational speed consistent with the target rotational speed. When the target rotational speed has been changed, the control rotational speed setting unit does not immediately change the control rotational speed to the target rotational speed. When the target rotational speed has been changed, the control rotational speed setting unit makes the control rotational speed gradually approach the target rotational speed. Specifically, the control rotational speed setting unit can make the control rotational speed increase or decrease monotonically toward the target rotational speed, for example.

[0068] In the electric working machine having at least features 1 to 11 and 14 to 16, the influence of the variation of the physical quantity accompanying the speed change can be effectively excluded from the total value.

[0069] A certain embodiment may include the following feature 17 in addition to or instead of at least any one of the above features 1 to 16.

[0070] Feature 17: The second period also includes a period from the target arrival timing until a waiting time (or a first time) has passed.

[0071] In the electric working machine having at least features 1 to 11 and 14 to 17, the influence of the change of the physical quantity accompanying the speed change can be more effectively excluded from the sum value. Specifically, for example, the influence of the so-called overshoot or undershoot of the actual rotation speed of the motor after the target reaching timing on the sum value (for example, the reliability of the sum value is reduced) can be excluded or suppressed.

[0072] A certain embodiment may include at least one of the following features 18 and 19 in addition to or instead of at least one of the features 1 to 17 described above.

[0073] Feature 18: The total value calculation unit is configured to calculate the total value by integrating the change amount every time the detection timing arrives during the first period.

[0074] Feature 19: The total value calculation unit is configured to reset (or initialize) the currently calculated total value based on (i) the at least one switch being manually turned on and (ii) the target rotation speed being changed as a result.

[0075] In the electric working machine having at least features 1 to 11, 18, and 19, when the target rotation speed has been changed, the total value accumulated so far is reset, and the change amount in the second period is excluded from the calculation of the total value. In other words, the reset state of the total value is maintained until the second period has passed. Therefore, it is possible to suppress the no-load state from being erroneously detected. Resetting the total value may include any method. Resetting the total value may, for example, include changing the total value to zero or a predetermined initial value.

[0076] A certain embodiment may include the following feature 20 and / or feature 21 in addition to or instead of at least any one of the above features 1 to 19.

[0077] Feature 20: The at least one switch includes a first switch.

[0078] Feature 21: The target setting unit is configured to change the target rotation speed in accordance with a position of the first switch.

[0079] In the electric working machine having at least features 1 to 11, 20, and 21, it is possible to improve the workability of the user when the motor is in the loaded state.

[0080] A certain embodiment may include the following feature 22 and / or feature 23 in addition to or instead of at least any one of the above features 1 to 21.

[0081] Feature 22: The at least one switch includes a second switch.

[0082] Feature 23: The target setting unit is configured to change the target rotation speed with a maximum rotation speed as an upper limit. The maximum rotation speed is determined according to the position of the second switch.

[0083] The second switch is used to set the maximum rotation speed. The target rotation speed sets the maximum rotation speed set by the second switch as an upper limit. For example, when the first switch is not set, the target rotation speed can be set to the maximum rotation speed set by the second switch. In addition, for example, when the first switch is set, the target rotation speed can be gradually increased to the maximum rotation speed according to the movement of the first switch.

[0084] In the electric working machine having at least features 1 to 11 and 20 to 23, the workability of the user can be improved when the motor is in the loaded state.

[0085] A certain embodiment may include the following feature 24 or feature 25 in addition to or instead of at least any one of the above features 1 to 23.

[0086] Feature 24: The no-load detection requirement is satisfied based on the fact that the total value calculated by the total value calculation unit has a predetermined magnitude, and the predetermined magnitude corresponds to a predetermined threshold value or less.

[0087] Feature 25: The no-load detection requirement is satisfied based on the fact that the total value calculated by the total value calculation unit has a predetermined magnitude, and the predetermined magnitude corresponds to or is equal to or greater than a predetermined threshold value.

[0088] In the electric working machine having at least features 1 to 6 and 24, and the electric working machine having at least features 1 to 6 and 25, it is possible to easily determine that the motor is in the no-load state. For example, it is assumed that the physical quantity decreases as the load decreases (that is, the physical quantity has such a property). An example of such a physical quantity may be the current flowing through the motor. In this case, due to feature 24, it is possible to easily determine that the motor is in the no-load state. In addition, for example, it is assumed that the physical quantity increases as the load decreases (that is, the physical quantity has such a property). An example of such a physical quantity may be the actual rotational speed of the motor. In this case, due to feature 25, it is possible to easily determine that the motor is in the no-load state.

[0089] A certain embodiment may include the following feature 26 in addition to or instead of at least any one of the above features 1 to 25.

[0090] Feature 26: The no-load detection requirement is satisfied based on the fact that the total value continuation determination time calculated by the total value calculation unit is maintained at the predetermined value.

[0091] In the electric working machine having at least features 1 to 6, 24, and 26, and the electric working machine having at least features 1 to 6, 25, and 26, it is possible to easily and accurately determine that the motor is in the no-load state.

[0092] A certain embodiment may include the following feature 27 in addition to or instead of at least any one of the above features 1 to 26.

[0093] Feature 27: The first control method includes rotating the motor at a first rotation speed. The first rotation speed is constant.

[0094] In the electric working machine having at least features 1 to 6 and 27, the rotation state of the motor when the motor is in the no-load state can be stabilized.

[0095] A certain embodiment may include the above-mentioned feature 27 and the following feature 28 in addition to or instead of at least any one of the above-mentioned features 1 to 26.

[0096] Feature 28: The first rotation speed is lower than the target rotation speed. The target rotation speed may be based on a state of the at least one switch.

[0097] In the electric working machine having at least features 1 to 6, 27, and 28, the rotation state of the motor when the motor is in the no-load state can be stabilized, and the operability of the motor when it shifts from the no-load state to the loaded state can be improved.

[0098] A certain embodiment may include the following feature 29 in addition to or instead of at least any one of the features 1 to 28 described above.

[0099] Feature 29: The physical quantity includes a current flowing through the motor.

[0100] In the electric working machine having at least features 1 to 6 and 29, it is possible to easily and accurately determine that the motor is in the no-load state.

[0101] The physical quantity acquisition unit may acquire any physical quantity that changes according to the magnitude of the load. The physical quantity may be, for example, the actual rotation speed of the motor. The physical quantity may be, for example, the voltage applied to the motor or a value indirectly representing the voltage.

[0102] One embodiment may provide a method of controlling a motor of an electric working machine including at least any one of the following features 30 to 33.

[0103] Feature 30: A physical quantity is acquired at each detection timing. The physical quantity is associated with an operating state of a motor. The motor is provided in the electric working machine.

[0104] Feature 31: A change amount is derived at each detection timing. The change amount corresponds to an increase from a previous physical amount to a current physical amount. The previous physical amount corresponds to the physical amount acquired at the previous detection timing. The current physical amount corresponds to the physical amount acquired at the current detection timing.

[0105] Feature 32: A total value is calculated at each detection timing. The total value corresponds to a sum of one or more amounts of change. The one or more amounts of change correspond to the amounts of change derived at each of the detection timings in the first period.

[0106] Feature 33: The motor is controlled according to a control method corresponding to the sum value.

[0107] By using the method having features 30 to 33 in the electric working machine, it is possible to accurately detect that the motor is in the no-load state (or that the motor changes from the loaded state to the no-load state).

[0108] In a certain embodiment, the above features 1 to 33 can be combined arbitrarily.

[0109] In a certain embodiment, any one of the above-mentioned features 1 to 33 may be eliminated.

[0110] Examples of the electric working machines include: various electric tools used at work sites such as amateur carpentry, manufacturing, gardening, and engineering, specifically electric tools for masonry, metalworking, carpentry, and gardening, and electric tools for adjusting the environment of the work site, more specifically electric wire saws, electric reciprocating saws, electric chainsaws, electric grinders, electric circular saws, electric cutters, electric hedge trimmers, electric mowers, electric lawn mowers, electric lawn mowers, electric screwdrivers, electric screwdrivers, electric drills, electric hammers, electric hammer drills, electric wrenches, electric planers, electric nailers (including riveters), etc.

[0111] The electric working machine can arbitrarily receive electric power for driving the motor. The electric working machine can include a battery, for example, and can be configured so that a battery pack including the battery can be detached. In this case, the electric working machine can be configured to receive electric power from the battery.

[0112] In a certain embodiment, the control circuit may be integrated into a single electronic unit or a single electronic device or a single circuit substrate.

[0113] In a certain embodiment, the control circuit may be a combination of two or more electronic circuits, two or more electronic units, or two or more electronic devices independently provided in the electric working machine.

[0114] In a certain embodiment, the control circuit may have: a microcomputer (or a microcontroller or a microprocessor), wiring logic, an application-specific integrated circuit (ASIC), an application-specific standard product (ASSP), a programmable logic device (such as a field programmable gate array (FPGA), etc.), discrete electronic components, and / or a combination thereof.

[0115] [2. Specific exemplary embodiments]

[0116] Hereinafter, exemplary embodiments of the present invention will be described.

[0117] (2-1) Overview of electric working machines

[0118] like Figure 1 As shown, the electric working machine 1 of this embodiment is in the form of a wire saw. The electric working machine 1 includes a housing 2. The housing 2 supports a driven tool 3. The driven tool 3 is detachably mounted on the housing 2. Figure 1 The electric working machine 1 is equipped with a driven tool 3. The driven tool 3 is in the form of a saw blade (ie, a jigsaw blade). The driven tool 3 is supported so as to be reciprocatingly movable.

[0119] The housing 2 is used for the motor 10 and various circuits described later (see Figure 2 The housing 2 accommodates the transmission mechanism (not shown).

[0120] The motor 10 is mechanically connected to the driven tool 3 by means of a transmission mechanism. The transmission mechanism transmits the rotation of the motor 10 to the driven tool 3. The rotational force of the motor 10 is transmitted to the driven tool 3 via the transmission mechanism, whereby the driven tool 3 is driven (i.e., reciprocated). The speed of the reciprocating motion of the driven tool 3 changes according to the rotation speed of the motor 10. If the rotation speed of the motor 10 increases, the speed of the driven tool 3 also increases, and if the rotation speed of the motor 10 decreases, the speed of the driven tool 3 also decreases.

[0121] The electric working machine 1 includes a battery pack 100. The housing 2 includes a mounting portion 4. The battery pack 100 is detachably mounted on the mounting portion 4. Figure 1 The battery pack 100 is shown in a state where it is mounted in the mounting portion 4. The battery pack 100 includes: a rechargeable battery 101 (see Figure 2 ). The battery 101 includes a plurality of battery cells. The battery 101 may be, for example, a lithium-ion battery.

[0122] The housing 2 includes a grip portion 5. The grip portion 5 is gripped by a user of the electric working machine 1.

[0123] The housing 2 includes a trigger (or a first switch) 6. The trigger 6 is manually moved (for example, pulled) by the user. The trigger 6 is in an initial position when not manually moved (that is, not pulled) by the user. The trigger 6 moves from the initial position when it is pulled from the initial position. When the trigger 6 is pulled, the motor 10 is driven, thereby driving the driven tool 3. The user can use the electric working machine 1 by pulling the trigger 6 while holding the grip 5. Specifically, the user can cut a workpiece (for example, wood, metal, resin parts, etc.) by the driven tool 3.

[0124] The housing 2 is provided with a speed adjustment dial (or a second switch) 7. The speed adjustment dial 7 is manually moved by the user in order to set the maximum value (i.e., the maximum rotational speed) of the rotational speed of the motor 10. The speed adjustment dial 7 of the present embodiment is rotated by the user. The user can select one of a plurality of maximum rotational speeds through the speed adjustment dial 7.

[0125] In this embodiment, as described later, the motor 10 is controlled according to the first control method or the second control method. The first control method is a control method for controlling the motor 10 according to soft no-load control. In the following description, executing soft no-load control and controlling the motor 10 by the first control method have the same meaning.

[0126] When the motor 10 is in a no-load state, soft no-load control is performed. The no-load state corresponds to a state where no load is applied to the motor 10. In this embodiment, the load is directly applied to the driven device 3. The load is applied to the motor 10 via the driven device 3. The no-load state may also be a state where no load is applied at all, or may include a state where a load of a certain size or less is applied. The certain size is greater than zero.

[0127] In the soft no-load control, the motor 10 is controlled so as to rotate at a constant first rotation speed regardless of the pulling amount (or moving amount) of the trigger 6 and the position of the speed adjustment dial 7 (that is, the set maximum rotation speed). The pulling amount or moving amount of the trigger 6 may be the pulling amount or moving amount from the initial position. The pulling amount or moving amount of the trigger 6 may also be the pulling amount or moving amount from the reference position. The reference position may be the same as the initial position, or may be a position moved (that is, pulled) a certain amount from the initial position.

[0128] The second control mode is executed when the motor 10 is in a loaded state. The loaded state means a state in which a load is applied to the motor 10. The loaded state may be a state in which a load greater than zero is applied, or a state in which a load greater than the above-mentioned certain magnitude is applied.

[0129] In the second control mode, the soft no-load control is released, and the motor 10 is controlled without using the soft no-load control. Specifically, in the second control mode, the target rotation speed is set according to the pulling amount of the trigger 6 and the position of the speed adjustment dial 7. The motor 10 is controlled to rotate at the set target rotation speed (specifically, at the control rotation speed described later). In other words, in the second control mode, the motor 10 is controlled in such a way that the actual rotation speed of the motor 10 is consistent with the control rotation speed.

[0130] (2-2) Electrical structure of electric working machine

[0131] like Figure 2 As shown, the electric working machine 1 includes a motor 10 and a controller 20. The controller 20 controls the rotation of the motor 10 and the reciprocating movement of the driven tool 3. Figure 2 The electric working machine 1 equipped with the battery pack 100 is shown electrically. When the battery pack 100 is mounted on the electric working machine 1 , the battery 101 is electrically connected to the controller 20 .

[0132] The motor 10 of the present embodiment is in the form of a three-phase brushless motor. The motor 10 includes a first terminal 10a, a second terminal 10b, and a third terminal 10c. The motor 10 receives three-phase power via the first to third terminals 10a to 10c, thereby rotating. The motor 10 includes three windings corresponding to the three phases, respectively. In the present embodiment, the three windings are connected to each other, for example, in a delta shape.

[0133] The electric working machine 1 has a rotation sensor 11. The rotation sensor 11 has three Hall ICs. The three Hall ICs are arranged at a predetermined angle apart from each other along the rotation direction of the motor 10 (specifically, the rotation direction of the rotor). The predetermined angle is an angle equivalent to 120 degrees in electrical angle. The three Hall ICs respectively output rotation detection signals corresponding to the position of the Hall IC and the rotation position of the rotor. The rotation detection signal is in the form of a pulse signal, for example. The three rotation detection signals from the rotation sensor 11 are input to the controller 20.

[0134] The electric working machine 1 includes a first detection unit 6a. The first detection unit 6a detects whether the trigger 6 has moved and the amount of movement. When the trigger 6 has been pulled, the first detection unit 6a outputs a trigger-on detection signal indicating that the trigger 6 has been pulled. The first detection unit 6a also outputs a first detection signal indicating the position of the trigger 6 (that is, the pulling amount or the moving amount). The first detection unit 6a includes a variable resistor. The resistance value of the variable resistor changes in conjunction with the movement of the trigger 6. The first detection unit 6a outputs a first detection signal corresponding to the resistance value of the variable resistor. The trigger-on detection signal and the first detection signal are input to the controller 20.

[0135] The electric working machine 1 includes a second detection unit 7a. The second detection unit 7a detects the position of the speed adjustment dial 7. The second detection unit 7a outputs a second detection signal indicating the position of the speed adjustment dial 7. The second detection signal is input to the controller 20.

[0136] The controller 20 can (i) recognize that the trigger 6 has been pulled based on the trigger-on detection signal, (ii) recognize the position of the trigger 6 based on the first detection signal, and (iii) recognize the position of the speed adjustment dial 7 based on the second detection signal.

[0137] The controller 20 includes a drive circuit 21 and a power line 20a. The power line 20a electrically connects the drive circuit 21 to the positive electrode of the battery 101. The drive circuit 21 is also electrically connected to a ground line. The drive circuit 21 is connected to the negative electrode of the battery 101 via the ground line.

[0138] The drive circuit 21 is connected to the motor 10. More specifically, the drive circuit 21 is connected to the first to third terminals 10a to 10c. The drive circuit 21 (i) receives battery power from the battery 101, (ii) converts the battery power into three-phase power, and (iii) supplies the three-phase power to the motor 10 via the first to third terminals 10a to 10c.

[0139] The drive circuit 21 of the present embodiment is in the form of a so-called three-phase full-bridge circuit. That is, the drive circuit 21 has three positive side paths and three negative side paths. The three positive side paths connect the first to third terminals 10a to 10c to the power line 20a, respectively. The three negative side paths electrically connect the first to third terminals 10a to 10c to the ground wire, respectively. The drive circuit 21 has three high-side switches and three low-side switches. The three high-side switches are respectively arranged on the three positive side paths. The three high-side switches respectively turn on or off the corresponding positive side paths. The three low-side switches are respectively arranged on the three negative side paths. The three low-side switches respectively turn on or off the corresponding negative side paths. In the present embodiment, the three high-side switches and the three low-side switches are in the form of semiconductor switch elements.

[0140] The controller 20 includes a ground connection path. The ground connection path electrically connects the drive circuit 21 to the ground. The ground connection path includes: (i) a first end connected to the drive circuit 21 (specifically, connected to each of the three negative electrode side paths), and (ii) a second end connected to the ground. The controller 20 includes a resistor R1 on the ground connection path. The current from the drive circuit 21 to the ground flows through the resistor R1.

[0141] The controller 20 includes a physical quantity detection circuit 22. The physical quantity detection circuit 22 detects a physical quantity associated with the operating state of the motor 10. The physical quantity detection circuit 22 of the present embodiment detects a motor current as an example. The motor current corresponds to the current supplied from the battery 101 to the motor 10. Specifically, the physical quantity detection circuit 22 includes a current detection circuit 22a. Both ends of the resistor R1 are connected to the current detection circuit 22a. The current detection circuit 22a outputs a current detection signal corresponding to the magnitude of the voltage between the two ends of the resistor R1. The current detection signal indicates the magnitude of the current flowing through the resistor R1. The motor current supplied from the battery 101 to the motor 10 flows through the resistor R1. Accordingly, the current detection signal indicates the magnitude of the motor current. The physical quantity detection circuit 22 outputs a physical quantity detection signal indicating the detected physical quantity. In the present embodiment, the physical quantity detection signal includes a current detection signal. The physical quantity detection signal is input to the control circuit 30.

[0142] The controller 20 includes a capacitor C1. The capacitor C1 is connected between the power supply line 20a and the ground line. The capacitor C1 smoothes the battery power supplied to the drive circuit 21.

[0143] The controller 20 includes a position detection circuit 23. The position detection circuit 23 receives three rotation detection signals from the rotation sensor 11. The position detection circuit 23 detects the rotation position of the motor 10 (specifically, the rotor) based on the three rotation detection signals. The position detection circuit 23 outputs a position signal corresponding to the detected rotation position.

[0144] The controller 20 includes a trigger detection circuit 24. The trigger detection circuit 24 receives a trigger-on detection signal and a first detection signal from the first detection unit 6a. The trigger detection circuit 24 outputs a trigger-on signal while receiving the trigger-on detection signal (that is, while the trigger 6 is pulled). The trigger-on signal indicates that the trigger 6 is pulled. The trigger detection circuit 24 also outputs a first command signal based on the first detection signal. The first command signal indicates the amount of pull of the trigger 6.

[0145] The controller 20 includes a dial detection circuit 25. The dial detection circuit 25 receives a second detection signal from the second detection unit 7a. The dial detection circuit 25 outputs a second command signal based on the second detection signal. The second command signal indicates the position of the speed adjustment dial 7. In other words, the second command signal indicates the maximum rotation speed selected in the speed adjustment dial 7.

[0146] The controller 20 includes a control circuit 30. The control circuit 30 controls the motor 10 via the drive circuit 21. In the present embodiment, the control circuit 30 is in the form of a microcomputer or micro control unit (MCU) including a CPU 30a and a memory 30b. The memory 30b includes a semiconductor memory such as a ROM or a RAM.

[0147] The various functions of the control circuit 30 are realized by the CPU 30a executing the program stored in the memory 30b. The method corresponding to the program is executed by executing the program. The memory 30b is an example of a non-migratable physical recording medium storing the program.

[0148] The memory 30b stores a motor control program for controlling the motor 10 (directly controlling the drive circuit 21). The CPU 30a executes the motor control program to control the motor 10. Figure 2 The physical quantity acquisition unit 31, the change amount derivation unit 32, the soft no-load determination unit 33, the drive control unit 34, and the rotation speed calculation unit 35 shown in the figure function. In other words, the physical quantity acquisition unit 31, the change amount derivation unit 32, the soft no-load determination unit 33, the drive control unit 34, and the rotation speed calculation unit 35 are functions implemented by software.

[0149] In other embodiments, part or all of the functions performed by the CPU 30a may be implemented by one or more electronic components such as discrete devices and integrated circuits (ICs). In addition, in other embodiments, the control circuit 30 may have one or more additional microcomputers or one or more additional MCUs. In addition, in other embodiments, the control circuit 30 may be in the form of a hard-wired circuit. Specifically, the control circuit 30 may have: a logic circuit (or a wired logic connection) including two or more electronic components. In addition, in other embodiments, the control circuit 30 may have an ASIC and / or an ASSP. In addition, in other embodiments, the control circuit 30 may have a programmable logic device that can construct a reconfigurable logic circuit. Examples of programmable logic devices include FPGAs.

[0150] The control circuit 30 receives a physical quantity detection signal from the physical quantity detection circuit 22. The control circuit 30 receives a position signal from the position detection circuit 23. The control circuit 30 receives a trigger-on signal from the trigger detection circuit 24. The control circuit 30 receives a first command signal from the trigger detection circuit 24. The control circuit 30 receives a second command signal from the dial detection circuit 25. The control circuit 30 controls the drive circuit 21 (and further controls the motor 10) based on the physical quantity detection signal, the position signal, the trigger-on signal, the first command signal, and / or the second command signal.

[0151] When the control circuit 30 does not receive the trigger on signal, the control circuit 30 stops the motor 10. When the control circuit 30 receives the trigger on signal, the control circuit 30 drives the motor 10. At this time, the control circuit 30 (i) sets the target rotation speed based on the first command signal and the second command signal, and (ii) controls the motor 10 according to the target rotation speed.

[0152] The rotation speed calculation unit 35 calculates the actual rotation speed of the motor 10 based on the position signal.

[0153] The physical quantity acquisition unit 31 acquires the physical quantity based on the physical quantity detection signal at each detection timing. As mentioned above, the physical quantity detection signal of the present embodiment includes a current detection signal. The physical quantity acquisition unit 31 acquires the magnitude of the motor current (hereinafter referred to as the "motor current value") based on the current detection signal. Therefore, the physical quantity acquisition unit 31 can be called the current value acquisition unit 31. In the present embodiment, the detection timing is repeated at a prescribed acquisition cycle. The acquisition cycle of the present embodiment is consistent with and synchronized with the control cycle described later.

[0154] The change amount derivation unit 32 derives the change amount of the physical quantity at each detection timing. The change amount corresponds to the increase (or degree of change) from the previous value to the current value. The previous value is the physical quantity acquired by the physical quantity acquisition unit 31 at the previous detection timing (that is, the detection timing whose acquisition cycle is earlier than the current detection timing). The current value is the physical quantity acquired by the physical quantity acquisition unit 31 at the current detection timing. The physical quantity acquisition unit 31 of the present embodiment acquires at least the motor current value. Based on this, the change amount derivation unit 32 of the present embodiment derives the change amount of the motor current value. Based on this, in the following description, the change amount is referred to as "current change amount".

[0155] The change amount deriving unit 32 can derive the current change amount by, for example, subtracting the previous value from the current value. That is, the current change amount can be the difference between the previous value and the current value. In other words, the current change amount can indicate how much the current value has changed (increased or decreased) compared to the previous value. Accordingly, the current change amount can be positive or negative.

[0156] Alternatively, the change amount derivation unit 32 may convert the increase from the previous value to the current value into a discrete numerical value, and derive the converted numerical value as the current change amount. Specifically, when the absolute value of the increase from the previous value to the current value is less than the specified reference value Io, the current change amount may be set to "0". When (i) the current value increases relative to the previous value and (ii) the increase is greater than the reference value Io, the current change amount may be set to "+1". When (i) the current value increases relative to the previous value and (ii) the increase is greater than twice the reference value Io, the current change amount may be set to "+2". When (i) the current value decreases relative to the previous value and (ii) the decrease is greater than the reference value Io, the current change amount may be set to "-1". When (i) the current value decreases relative to the previous value and (ii) the decrease is greater than twice the reference value Io, the current change amount may be set to "-2".

[0157] The soft no-load determination unit 33 determines whether the motor 10 is in an unloaded state or a loaded state, and generates a predetermined command based on the determination result. Specifically, the soft no-load determination unit 33 sets or clears a soft no-load release determination flag based on the determination result.

[0158] When the drive of the motor 1 starts, the soft no-load determination unit 33 determines that the motor 10 is in a no-load state. The soft no-load determination unit 33 makes an execution decision (or execution determination) of the soft no-load control based on the determination that the motor 10 is in a no-load state. The execution decision includes determining (or determining) that the soft no-load control should be executed. The execution decision includes issuing an instruction to the drive control unit 34 to execute the soft no-load control. The execution decision includes clearing the soft no-load release determination flag.

[0159] The soft no-load determination unit 33 makes a decision to release the soft no-load control (or a release determination) based on the determination that the no-load state has changed to the load state. The release determination includes determining (or determining) that the soft no-load control should be released. The release determination includes issuing an instruction to the drive control unit 34 to stop the soft no-load control. The release determination includes setting a soft no-load release determination flag.

[0160] Whether the motor 10 is in a loaded state can be determined by any method. For example, it can be determined that the motor 10 is in a loaded state based on the motor current value exceeding a predetermined current threshold. Alternatively, the load state detection method described in Patent Document 1 described above can be used for determination.

[0161] The soft no-load determination unit 33 determines whether to execute the soft no-load control based on the determination that the load state has changed to the no-load state.

[0162] In order to determine whether the motor 10 is in the no-load state, the soft no-load determination unit 33 of the present embodiment includes a sum value calculation unit 40. The sum value calculation unit 40 calculates the sum value at each detection timing. The sum value corresponds to the sum of the current change amounts derived by the change amount deriving unit in the first period. The first period corresponds to the period from the first calculation start timing to the current detection timing. The sum value includes the current change amount at the current detection timing.

[0163] The total value calculation unit 40 may calculate the total value by any method. In the present embodiment, the total value calculation unit 40 calculates the total value by integrating (ie, cumulatively adding) the current variation every time the detection timing arrives during the first period.

[0164] The first calculation start timing corresponds to the start time of the first period. The first calculation start timing can be determined arbitrarily. In the present embodiment, the first calculation start timing is after the load state of the motor 10 is determined and at least after the target reach timing. The target reach timing corresponds to the timing when the controlled rotation speed has reached the target rotation speed. More specifically, the first calculation start timing of the present embodiment is when the first standby time has passed from the target reach timing. The period from the target reach timing to the first standby time is referred to as the first load stabilization period.

[0165] The total value calculation unit 40 also has the following characteristics. That is, the total value calculation unit 40 excludes the current change amount in the second period from the calculation of the total value based on the speed change operation. The second period corresponds to the period from the speed change timing to the predetermined timing. The speed change timing corresponds to the timing when the speed change operation is performed. The speed change operation includes the operation of moving the trigger 6 and / or the speed adjustment dial 7. More specifically, the speed change operation includes the operation of moving the trigger 6 and / or the speed adjustment dial 7 so that the target rotation speed is changed by the target setting unit 41.

[0166] The total value calculation unit 40 stops accumulating the current change amount based on the speed change operation until the second period has passed. The total value calculation unit 40 resets (or initializes) the total value accumulated until the current moment (i.e., the speed change timing) based on the speed change operation. Moreover, the total value calculation unit 40 re-accumulates after the second period has passed. In this case, the total value calculation unit 40 may not accumulate at the initial detection timing after the second period has passed. The total value calculation unit 40 may start accumulating from the second detection timing after the second period has passed. Alternatively, the change derivation unit 32 may avoid deriving the current change amount at the initial detection timing after the second period has passed. In other words, at this initial detection timing, a value of zero or close to zero can be derived as the current change amount.

[0167] Resetting (or initializing) the sum value may include, for example, setting the sum value to zero, and may also include, for example, setting the sum value to a prescribed initial value.

[0168] The second period can be determined arbitrarily. In the present embodiment, the second period includes a target reaching period and a second load stabilization period. The target reaching period is the period from the speed change timing (or from the target rotation speed being changed by the speed change operation) to the target reaching timing. The second load stabilization period is the period from the target reaching timing to the second standby time.

[0169] After the rotational speed is controlled to reach the target rotational speed, the actual rotational speed of the motor 10 may change immediately. Specifically, a so-called overshoot or undershoot of the actual rotational speed may occur. The second load stabilization period is a period set in consideration of such changes in the actual rotational speed. The same is true for the first load stabilization period described above. Accordingly, the first load stabilization period and the second load stabilization period may be determined in consideration of the convergence time, respectively. The convergence time corresponds to the time required for the change in the actual rotational speed to converge to below a certain level. In the present embodiment, the second standby time is the same as the first standby time. However, the second standby time may be different from the first standby time.

[0170] The soft no-load determination unit 33 (i) determines that the motor 10 is in the no-load state and (ii) determines to execute the soft no-load control based on the fact that the sum calculated by the sum calculation unit 40 satisfies the no-load detection requirement.

[0171] The no-load detection requirement is required to detect that the motor 10 is in the no-load state. The no-load detection requirement can be determined arbitrarily. In the present embodiment, the no-load detection requirement is satisfied based on the fact that the calculated sum value is maintained below a predetermined current threshold value during a predetermined recovery determination time.

[0172] The drive control unit 34 controls the motor 10 according to the first control method or the second control method. That is, when the motor 10 is in an unloaded state (that is, when a decision to execute the soft no-load control is made), the drive control unit 34 controls the motor 10 according to the first control method (that is, using the soft no-load control) with the help of the drive circuit 21. When the motor 10 is in a loaded state (that is, when a decision to cancel the soft no-load control is made), the drive control unit 34 controls the motor 10 according to the second control method (that is, not using the soft no-load control) with the help of the drive circuit 21.

[0173] The drive control unit 34 includes a target setting unit 41. The target setting unit 41 sets a target rotation speed based on the first command signal and the second command signal.

[0174] The target setting unit 41 sets the target rotation speed to a predetermined initial target value (e.g., zero) when, for example, the pulling amount of the trigger 6 is less than the first pulling amount. The first pulling amount may be zero or may be greater than zero. When the pulling amount exceeds the first pulling amount, the target setting unit 41 sets the target rotation speed according to the pulling amount. Specifically, the target setting unit 41 sets the target rotation speed in such a manner that the target rotation speed becomes higher continuously or in stages as the pulling amount increases. At this time, the target setting unit 41 sets the target rotation speed with the maximum rotation speed as the upper limit. Specifically, the target setting unit 41 sets the target rotation speed in such a manner that the target rotation speed reaches the maximum rotation speed when the pulling amount reaches the second pulling amount. The second pulling amount is greater than the first pulling amount. The second pulling amount may correspond to the maximum pulling amount. The second pulling amount may also be less than the maximum pulling amount. The maximum pulling amount corresponds to the pulling amount when the trigger 6 is pulled to the maximum limit. When the pulling amount exceeds the second pulling amount, the target setting unit 41 maintains the target rotation speed at the maximum rotation speed.

[0175] In the present embodiment, the soft no-load control is mainly implemented by the target setting unit 41. Specifically, the target setting unit 41 switches the method for setting the target rotation speed according to whether the motor 10 is in a loaded state or in an unloaded state. In other words, the target setting unit 41 switches the method for setting the target rotation speed according to whether a decision to execute the soft no-load control is made or a decision to cancel the soft no-load control is made. In addition, in other words, the target setting unit 41 switches the method for setting the target rotation speed according to whether the drive control unit 34 issues an instruction from the soft no-load determination unit 33 to execute the soft no-load control or issues an instruction to stop executing the soft no-load control.

[0176] When the motor 10 is in a loaded state (that is, when a decision to release the soft no-load control is made), the target setting unit 41 sets a target rotation speed of the motor 10 based on the first command signal and the second command signal.

[0177] On the other hand, when the motor 10 is in the no-load state (that is, when the soft no-load control is determined to be executed), the target setting unit 41 sets the target rotation speed to the first rotation speed (that is, maintains the first rotation speed). The first rotation speed can be arbitrarily determined. The first rotation speed can be the same as the target rotation speed set when the trigger 6 is pulled by a predetermined pulling amount in the second control mode, for example. In other words, the first rotation speed can be lower than the target rotation speed set by the second control mode when the trigger 6 is pulled more than the predetermined pulling amount.

[0178] The drive control unit 34 includes a control rotational speed setting unit 42. The control rotational speed setting unit 42 sets the control rotational speed based on the target rotational speed set by the target setting unit 41. The control rotational speed setting unit 42 basically makes the control rotational speed consistent with the target rotational speed. When the target rotational speed has been changed, the control rotational speed is also changed to the changed new target rotational speed.

[0179] However, when the target rotational speed has been changed, the control rotational speed setting unit 42 does not immediately change the control rotational speed to the new target rotational speed. When the target rotational speed has been changed, the control rotational speed setting unit 42 gradually approaches the control rotational speed from the current control rotational speed to the new target rotational speed at a prescribed rate of change. The control rotational speed setting unit 42 may also increase or decrease the control rotational speed toward the new target rotational speed, for example, monotonically. The prescribed rate of change may be constant or variable. In the present embodiment, the prescribed rate of change is constant. That is, in the present embodiment, when the target rotational speed has been changed, the control rotational speed changes linearly toward the new target rotational speed.

[0180] The drive control unit 34 includes a motor control unit 43. The motor control unit 43 generates a drive command. The drive command makes the actual rotation speed of the motor 10 consistent with the control rotation speed set by the control rotation speed setting unit 42. The drive command is output to the drive circuit 21. The drive command issues a command to turn on or off each of the six semiconductor switching elements of the drive circuit 21. The drive circuit 21 converts the battery power into three-phase power according to the drive command.

[0181] The drive command includes a pulse width modulation (PWM) signal. The PWM signal causes one of the six semiconductor switch elements to perform duty driving. Duty driving includes turning on and off the semiconductor switch element to be driven according to a set duty ratio.

[0182] The motor control unit 43 determines the semiconductor switch element to be turned on based on the position signal. At this time, the motor control unit 43 also determines the semiconductor switch element to be duty-driven. The motor control unit 43 obtains the actual rotation speed calculated by the rotation speed calculation unit 35. The motor control unit 43 calculates the duty ratio based on the difference between the actual rotation speed obtained and the control rotation speed.

[0183] In this embodiment, as described above, when the motor 10 starts to be driven, it is determined that the motor 10 is in a no-load state, and the soft no-load control is performed. That is, when the motor 10 starts to be driven, the target rotation speed is set to the first rotation speed to drive the motor 10 regardless of the state of the trigger 6 and the speed adjustment dial 7. The first rotation speed may be, for example, a predetermined low rotation speed corresponding to a duty cycle of 50%.

[0184] After the motor 10 starts to be driven, if it is detected that the motor 10 is in a loaded state, the soft no-load control is released (ie, stopped). Thus, the motor 10 is controlled by the second control method.

[0185] When the control is performed by the second control method, when it is detected that the motor 10 is in the no-load state, the soft no-load control is executed.

[0186] However, in the present embodiment, when the pulling amount of the trigger 6 is less than the prescribed pulling amount, the soft no-load control is not performed and the motor 10 is controlled by the second control method. Therefore, even when the driving of the motor 10 has just started or even when the motor 10 is in a no-load state, when the pulling amount of the trigger 6 is less than the prescribed pulling amount, (i) a target rotation speed corresponding to the maximum rotation speed determined based on the pulling amount and the speed adjustment dial 7 is set, and (ii) the motor 10 is driven according to the target rotation speed.

[0187] In the present embodiment, in the soft no-load control, feedback control is performed so that the actual rotation speed is consistent with the first rotation speed. However, in the soft no-load control, the motor 10 may be open-loop controlled at a duty ratio (e.g., 50%) corresponding to the first rotation speed. In the second control mode, the motor 10 may also be open-loop controlled. When the execution decision of the soft no-load control is made, the soft no-load control may be executed regardless of the pulling amount of the trigger 6.

[0188] (2-3) Operation example of electric working machine

[0189] Next, refer to Figure 3 as well as Figure 4 An operation example of the electric working machine 1 will be described. Figure 3 as well as Figure 4 Both show an example in which the motor 10 changes to a loaded state and then changes to a no-load state after the driving of the motor 10 starts. Figure 3 In the load state, a speed change operation is performed to reduce the rotation speed of the motor 10. Figure 4 During the load state, a speed change operation is performed to increase the rotation speed of the motor 10.

[0190] exist Figure 3 as well as Figure 4 In FIG. 1 , “no-load current” indicates the motor current when the motor 10 is maintained in a no-load state. “Detected current” indicates the motor current value actually acquired by the physical quantity acquisition unit 31 .

[0191] First of all, Figure 3 At time t00, the trigger 6 is pulled to start the driving of the motor 10. As described above, at the start of the driving, it is determined to be a no-load state and the soft no-load control is performed. Therefore, at the start of the driving, the target rotation speed is limited to the first rotation speed.

[0192] At time t01, the work (for example, cutting of a workpiece) by the driven tool 3 starts, and the motor 10 changes to a loaded state. However, at time t01, the control circuit 30 has not yet determined the loaded state.

[0193] At time t02, the control circuit 30 determines the load state of the motor 10, thereby releasing the soft no-load control. Figure 3 as well as Figure 4In the figure, "SNL" means soft no-load control. By releasing the soft no-load control, the target rotation speed changes to a speed corresponding to the instruction from the user (i.e., the state of the trigger 6 and the speed adjustment dial 7). The control rotation speed gradually increases toward the new target rotation speed after the change. At time t03, the control rotation speed reaches the target rotation speed. Time t03 corresponds to the target reaching timing. As the control rotation speed increases, the motor current value also increases.

[0194] Time t04 corresponds to the timing when the first standby time has passed since time t03. At time t04, the calculation of the total value (i.e., the accumulation of the current change amount) starts. In other words, time t04 corresponds to the first calculation start timing (i.e., the beginning of the first period). The period from time t03 to t04 corresponds to the first load stabilization period.

[0195] At time t05, the user performs a speed change operation to reduce the rotation speed of the motor 10. As a result, the accumulation of the current change amount is stopped. In addition, the currently calculated total value is reset. Time t05 corresponds to the speed change timing. At time t05, the target rotation speed also changes according to the speed change operation. The rotation speed is controlled to gradually change toward the new target rotation speed after the change (here it is reduced), and at time t06, the target rotation speed is reached. Time t06 corresponds to the target achievement timing. The period from time t05 to t06 corresponds to the target achievement period.

[0196] Time t07 corresponds to the timing when the second waiting time has elapsed from time t06. The period from time t06 to t07 corresponds to the second load stabilization period. At time t07, the integration of the current change amount (that is, the calculation of the total value) is restarted.

[0197] At time t08, when the trigger 6 is pulled, the operation of the driven tool 3 is temporarily interrupted. That is, the driven tool 3 is separated from the workpiece. As a result, the motor 10 changes to a no-load state. However, at time t08, the control circuit 30 has not yet determined the no-load state.

[0198] The motor current value is greatly reduced due to the change to the no-load state at time t08. As a result, at time t09, the sum value becomes less than the current threshold. Time t10 corresponds to the timing when the recovery determination time has passed since time t09. At time t10, the no-load state is determined. That is, the no-load state of the motor 10 is determined based on the fact that the sum value continues to be less than the current threshold for the recovery determination time. As a result, at time t10, soft no-load control is performed again.

[0199] Next, Figure 4 The following describes an example of the operation. Figure 4The operation example during the period from time t00 to time t15 is similar to Figure 3 The operation example during the time period t00 to t05 is substantially the same. Figure 4 , the description of the period from time t00 to time t15 is omitted.

[0200] Figure 4 At time t15, the user performs a speed change operation to increase the rotation speed of the motor 10. As a result, the accumulation of the current change amount is stopped. In addition, the currently calculated total value is reset. Time t15 corresponds to the speed change timing. At time t15, the target rotation speed also changes according to the speed change operation. The rotation speed is controlled to gradually change toward the new target rotation speed after the change (increases here), and reaches the target rotation speed at time t16. Time t16 corresponds to the target achievement timing. The period from time t15 to t16 corresponds to the target achievement period.

[0201] Time t17 corresponds to the timing when the second waiting time has elapsed from time t16. The period from time t16 to t17 corresponds to the second load stabilization period. At time t17, the integration of the current change amount (that is, the calculation of the total value) is restarted.

[0202] At time t18, when the trigger 6 is pulled, the operation of the driven tool 3 is temporarily interrupted. That is, the driven tool 3 is separated from the workpiece. As a result, the motor 10 changes to a no-load state. However, at time t18, the control circuit 30 has not yet determined the no-load state.

[0203] The motor current value is greatly reduced due to the change to the no-load state at time t18. As a result, at time t19, the sum value becomes less than the current threshold. Time t20 corresponds to the timing when the recovery determination time has passed since time t19. At time t20, the no-load state is determined. That is, the no-load state of the motor 10 is determined based on the fact that the sum value continues to be less than the current threshold for the recovery determination time. As a result, at time t20, soft no-load control is performed again.

[0204] (2-4) Main Processing

[0205] Reference Figures 5 to 8 , the main processing executed by the control circuit 30 (more specifically, the CPU 30a) is described. The motor 10 is controlled by the main processing. The above-described operation example of the motor 10 is realized by the control circuit 30 executing the main processing. In other words, Figure 2 The physical quantity acquisition unit 31, the change amount derivation unit 32, the soft no-load determination unit 33, the drive control unit 34, and the rotation speed calculation unit 35 are implemented by executing a main process. The program of the main process is stored in the memory 30b, for example.

[0206] The control circuit 30 repeatedly executes the main process in a predetermined control cycle after startup. When the main process starts, the control circuit 30 executes the motor information acquisition process in S110. Specifically, the control circuit 30 acquires the pulling amount of the trigger 6, the maximum rotation speed selected by the speed adjustment dial 7, the actual rotation speed of the motor 10, the motor current value, the current change amount, etc.

[0207] Figure 5 Although not shown in the figure, after the main process starts and before the process of S110, a predetermined initial process is executed. In this initial process, the motor 10 is regarded as being in a no-load state. Thus, the soft no-load control is executed.

[0208] In S120, the control circuit 30 performs a soft no-load release determination process. Specifically, the control circuit 30 determines whether the soft no-load control should be released. The process of S120 is performed when the soft no-load control is executed. The process of S120 is not performed when the soft no-load control is not executed (that is, in the load state).

[0209] Specifically, in S120, the control circuit 30 determines whether the motor 10 is in a loaded state. If the control circuit 30 determines that the motor 10 is in a loaded state, the control circuit 30 makes a decision to cancel the soft no-load control. If the decision to cancel is made, the recovery decision described later is canceled.

[0210] In S130, the control circuit 30 performs a soft no-load recovery determination process. Specifically, the control circuit 30 determines whether to recover to the soft no-load control. The process of S130 is performed when the soft no-load control is not performed. The process of S130 is not performed when the soft no-load control is performed (that is, in the no-load state).

[0211] Specifically, in S130, the control circuit 30 determines whether the motor 10 is in a no-load state. If the control circuit 30 determines that the motor 10 is in a no-load state, the control circuit 30 performs a recovery decision (or recovery determination) of the soft no-load control. The details of the processing of S130 are as follows: Figure 6 shown.

[0212] like Figure 6 As shown, when the control circuit 30 transfers to the soft no-load recovery determination process, it determines whether the motor 10 is being driven in S210. The control circuit 30 can determine whether the motor 10 is being driven based on whether the specified requirements are satisfied. The specified requirements can be based on various states of the electric working machine 1. The various states of the electric working machine 1 can include, for example, an operation state in which the user operates the trigger 6. For example, it can be determined that the motor 10 is being driven based on the trigger 6 being pulled.

[0213] When the motor 10 is stopped, the control circuit 30 ends the soft no-load recovery determination process and moves to S140 (see Figure 5 ). When the motor 10 is stopped, the control circuit 30 determines whether the soft no-load application requirement is satisfied in S220. The soft no-load application requirement is required in order to determine that the motor 10 is in a state where the soft no-load control can be performed. In this embodiment, the soft no-load application requirement is satisfied based on the pull amount of the trigger 6 being greater than the specified pull amount.

[0214] If the soft no-load application requirement is not satisfied in S220, the control circuit 30 ends the soft no-load recovery determination process and transfers to S140. That is, if the soft no-load application requirement is not satisfied, the soft no-load control is not performed even if the motor 10 is in a no-load state. If the soft no-load application requirement is satisfied, the process transfers to S230.

[0215] In S230, the control circuit 30 determines whether a decision to release the soft no-load control has been made. If a decision to release has not been made (that is, if a load state has not been detected), the control circuit 30 ends the soft no-load recovery determination process and moves to S140. If a decision to release has been made (that is, if a load state has been detected), the process moves to S240.

[0216] In S240, the control circuit 30 determines whether a speed change has occurred. The control circuit 30 may determine that a speed change has occurred, for example, based on a speed change operation performed by a user. Alternatively, the control circuit 30 may determine that a speed change has occurred based on the target rotation speed actually changing in response to the speed change operation.

[0217] When a speed change occurs, the process transfers to S330. In S330, the control circuit 30 resets the currently calculated total value. After the total value is reset in S330, the calculation of the total value is stopped until the second period has passed. In other words, the current change amount in the second period is excluded from the calculation of the total value. In other words, the current change amount is not accumulated in the second period. After the total value is reset, if the second period has passed, an affirmative judgment is made in S260 described later, and the calculation of the total value is restarted in S270. After the processing of S330, the process transfers to S140.

[0218] When no speed change occurs in S240, the process transfers to S250. In S250, the control circuit 30 determines whether the control rotational speed is consistent with the target rotational speed. When the control rotational speed is not consistent with the target rotational speed, the process transfers to S140. When the soft no-load control is released, the control rotational speed gradually approaches the target rotational speed. When a speed change is performed, the control rotational speed also gradually approaches the new target rotational speed after the speed change. Therefore, after the soft no-load control is released or the speed change is performed, a negative judgment is made in S250 until the target reaches the timing. When the control rotational speed is consistent with the target rotational speed, the process transfers to S260.

[0219] In S260, the control circuit 30 determines whether the load stabilization period has passed since the target arrival timing. In other words, in S260, the control circuit 30 determines whether the first standby time has passed since the target arrival timing after the soft no-load control is released. After the speed change, the control circuit 30 determines whether the second standby time has passed since the target arrival timing. As described above, in this embodiment, the first standby time is the same as the second standby time.

[0220] If the load stabilization period has not passed in S260, the process proceeds to S140. If the load stabilization period has passed in S260, the process proceeds to S270.

[0221] In S270, the control circuit 30 updates the total value. That is, the control circuit 30 accumulates the current change. When the process is transferred to S270 for the first time after the speed change, the total value is reset. Accordingly, in this case, the calculation of the total value is restarted from the reset value (for example, zero). After the process of S270, the process is transferred to the determination process of the no-load detection requirement (see Figure 7 The determination process of the no-load detection requirement includes S280, S300, and S310. The determination process of the no-load detection requirement includes: determining whether the no-load detection requirement is satisfied.

[0222] In S280, the control circuit 30 determines whether the currently calculated total value is below the current threshold. When the total value is greater than the current threshold, the process transfers to S290. In S290, the control circuit 30 resets the no-load maintenance time (for example, updates it to zero). The no-load maintenance time refers to the time for maintaining the state in which the total value is below the current threshold. The start time of the no-load maintenance time is the timing of the affirmative judgment in S280 (however, a negative judgment is required in the previous S280). In other words, the start time of the no-load maintenance time corresponds to the time point when the total value changes from a state greater than the current threshold to a state below the current threshold. After the processing of S290, the process transfers to S140.

[0223] When the total value is equal to or less than the current threshold value, the control circuit 30 measures the no-load maintenance time in S300. Specifically, the control circuit 30 increases (accumulates) the current no-load maintenance time to update the no-load maintenance time.

[0224] In S310, the control circuit 30 determines whether the current no-load maintenance time is longer than the recovery determination time. If the no-load maintenance time has not reached the recovery determination time, the process moves to S140. If the no-load maintenance time is longer than the recovery determination time, the process moves to S320. The no-load maintenance time being longer than the recovery determination time corresponds to the no-load detection requirement being satisfied.

[0225] In S320, the control circuit 30 (i) determines that the motor 10 is in the no-load state, and (ii) makes a recovery decision of the soft no-load control based on the determination. If the recovery decision is made after the release decision is made, the release decision is released. After the processing of S320, the present processing transfers to S140.

[0226] In S140 (ref. Figure 5 ), the control circuit 30 performs a target rotation speed determination process. The details of the target rotation speed determination process are as follows: Figure 8 As shown. When the control circuit 30 transfers to the target rotation speed determination process, it determines whether the soft no-load application requirement is satisfied in S410. The process of S410 is the same as S220. If the soft no-load application requirement is not satisfied, the process transfers to S440. If the soft no-load application requirement is satisfied, the process transfers to S420.

[0227] In S420, the control circuit 30 determines whether a decision to release the soft no-load control has been made. If a decision to release has not been made, the process moves to S450. For example, immediately after the start of the drive of the motor 10 or when it is determined that the motor 10 is in an unloaded state, it is determined in S420 that a decision to release has not been made.

[0228] In S450, the control circuit 30 sets the target rotation speed to the first rotation speed. That is, the control circuit 30 sets the target rotation speed used in the soft no-load control. After the processing of S450, the present processing transfers to S150 (refer to Figure 5 ).

[0229] If the decision to cancel is made in S420, the process moves to S430. In S430, the control circuit 30 determines whether the decision to resume the soft no-load control is made. If the decision to resume is made, the process moves to S450. In this case, the target rotation speed is set to the first rotation speed corresponding to the soft no-load control.

[0230] If the recovery decision is not made, the process proceeds to S440. In S440, the control circuit 30 sets the target rotation speed based on the trigger 6 and the speed adjustment dial 7. After the process of S440, the process proceeds to S150.

[0231] In S150 (ref. Figure 5 ), the control circuit 30 performs motor control processing. Specifically, the control circuit 30 sets the control rotation speed based on the currently set target rotation speed. The control circuit 30 calculates the duty cycle based on the control rotation speed and the actual rotation speed. The control circuit 30 outputs a drive instruction to the drive circuit 21, thereby driving the motor 10.

[0232] (2-5) Correspondence of terms

[0233] In the above-mentioned embodiment, the trigger 6 and the speed adjustment dial 7 are equivalent to an example of at least one switch in the summary of the embodiment. The trigger 6 is equivalent to an example of the first switch in the summary of the embodiment. The speed adjustment dial 7 is equivalent to an example of the second switch in the summary of the embodiment. The second standby time is equivalent to an example of the standby time in the summary of the embodiment. The current threshold is equivalent to an example of the prescribed threshold in the summary of the embodiment. The recovery determination time is equivalent to an example of the determination time in the summary of the embodiment.

[0234] [3. Other embodiments]

[0235] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Various deformation|transformation can be carried out.

[0236] (3-1) In the above embodiment, when a speed change operation is performed, (i) the currently calculated total value is reset, and (ii) the accumulation of the current change amount is avoided (that is, the current change amount in the second period is excluded from the total value) until the second period has passed.

[0237] However, the calculation of the total value when the speed change operation is performed may be performed by other methods. In other words, the current change amount may be excluded from the calculation of the total value in the second period at will.

[0238] For example, the total value is not necessarily reset. Specifically, the total value at the time when the speed change operation is performed may be maintained during the second period. After the second period has passed, the accumulation of the current change amount is restarted from the maintained total value.

[0239] In addition, for example, the total value may be calculated by a method different from accumulation. For example, the total of the current changes in the first period may be calculated one by one at each detection timing. Furthermore, when a speed change operation is performed, the start time of the first period may be changed from the first calculation start timing to the second calculation start timing. The second calculation start timing corresponds to the end time of the second period.

[0240] (3-2) The second period can be determined arbitrarily. For example, the second period may not include the second waiting time.

[0241] (3-3) The total value calculation unit 40 may calculate the total value of other variation amounts different from the current variation amount. The soft no-load determination unit 33 may determine the no-load state of the motor 10 based on the total value of other variation amounts.

[0242] The other variation may be a variation of a prescribed physical quantity. The prescribed physical quantity (i) is different from the motor current and (ii) is associated with the operating state of the motor 10. The prescribed physical quantity may include a parameter used in the control of the motor 10. The prescribed physical quantity may be, for example, the actual rotation speed of the motor 10, the voltage to be applied or being applied to the motor 10, or the duty cycle of the PWM signal.

[0243] (3-4) The target rotation speed set in the soft no-load control may not be constant. The target rotation speed may also change when the soft no-load control is executed. For example, the target rotation speed may also change according to the change in the pulling amount of the trigger 6. In this case, a target rotation speed lower than the target rotation speed set when the soft no-load control is released may be set.

[0244] (3-5) The drive control unit 34 can arbitrarily implement soft no-load control. In the above embodiment, the target setting unit 41 plays a substantial role in the soft no-load control. That is, in the above embodiment, the target setting unit 41 sets the target rotation speed to the first rotation speed based on the satisfaction of the no-load detection requirement.

[0245] In contrast, for example, the control rotation speed setting unit 42 may play a substantial role in the soft no-load control. Specifically, the control rotation speed setting unit 42 may set the control rotation speed to a constant speed regardless of the currently set target rotation speed based on the satisfaction of the no-load detection requirement.

[0246] Alternatively, the motor control unit 43 may also play a substantial role in the soft no-load control. Specifically, the motor control unit 43 may perform constant speed control on the motor 10 regardless of the target rotation speed and the control rotation speed based on the satisfaction of the no-load detection requirement. Specifically, the motor control unit 43 may generate a drive instruction for rotating the motor 10 at the first rotation speed.

[0247] (3-6) It is not necessary to gradually bring the controlled rotational speed closer to the target rotational speed in response to a change in the target rotational speed. The controlled rotational speed may always be consistent with the target rotational speed. In other words, the controlled rotational speed setting unit 42 may be omitted. In this case, the motor control unit 43 may control the motor 10 in accordance with the target rotational speed set by the target setting unit 41.

[0248] (3-7) The trigger 6 or the speed adjustment dial 7 may be omitted. The “at least one switch” in the summary of the embodiments may be realized in a form different from the trigger 6 and the speed adjustment dial 7 .

[0249] (3-8) The motor 10 of the above embodiment is a three-phase brushless motor. However, the motor of the present invention may be a motor other than a three-phase brushless motor (eg, a brushed DC motor, various AC motors, etc.).

[0250] (3-9) In the above-mentioned embodiments, multiple functions of one component can be realized by multiple components, or one function of one component can be realized by multiple components. In addition, multiple functions of multiple components can be realized by one component, or one function realized by multiple components can be realized by one component. In addition, part of the components of the above-mentioned embodiments can be omitted. In addition, at least part of the components of the above-mentioned embodiments can be added to the components of other above-mentioned embodiments, or replaced with them.

Claims

1. An electric working machine comprising: a motor configured to drive a driven tool mounted on the electric working machine; a drive circuit configured to drive the motor; and A control circuit includes a physical quantity acquisition unit, a change amount derivation unit, a total value calculation unit, and a drive control unit. The physical quantity acquisition unit is configured to acquire a physical quantity at each detection timing, wherein the physical quantity is associated with an operating state of the motor. The variation deriving unit is configured to derive a variation at each detection timing, the variation corresponding to an increase from a previous physical quantity to a current physical quantity, the previous physical quantity corresponding to the physical quantity acquired at the previous detection timing, and the current physical quantity corresponding to the physical quantity acquired at the current detection timing, The total value calculation unit is configured to calculate a total value at each detection timing, the total value corresponding to the sum of one or more variation amounts, the one or more variation amounts respectively corresponding to the variation amounts derived at each detection timing in a first period, the first period being a period from a first calculation start timing to the current detection timing, The drive control unit is configured to control the motor with the help of the drive circuit and according to the first control method based on the fact that the total value calculated by the total value calculation unit satisfies or has satisfied a no-load detection requirement, wherein the no-load detection requirement is required to detect that no load is applied to the motor.

2. The electric working machine according to claim 1, wherein: The electric working machine further includes at least one switch, and the at least one switch is configured to be manually operated by a user of the electric working machine. The control circuit further includes a target setting unit configured to set a target rotation speed of the motor based on a state of the at least one switch. The drive control unit is configured to control the motor according to a second control method based on the fact that the total value does not satisfy the no-load detection requirement. The second control method (i) is different from the first control method in that (ii) the motor is controlled so as to rotate at the target rotation speed set by the target setting unit.

3. The electric working machine according to claim 2, wherein: The total value calculation unit is configured to exclude the change amount derived by the change amount deriving unit in the second period from calculation of the total value based on the target rotation speed being changed by the at least one switch, The second period corresponds to a period from a speed change timing to a predetermined timing, and the speed change timing corresponds to a timing at which the target rotation speed is changed.

4. The electric working machine according to claim 3, wherein: The total value calculation unit is configured to switch the start time of the first period from the first calculation start timing to the second calculation start timing based on the target rotation speed being changed by the at least one switch, The second calculation start timing corresponds to the predetermined timing.

5. The electric working machine according to claim 3 or 4, wherein: The control circuit further includes a control rotational speed setting unit configured to: (i) set the control rotational speed based on the target rotational speed; and (ii) gradually change the control rotational speed to the changed target rotational speed based on a change in the target rotational speed. The second control method includes controlling the motor in such a manner that the actual rotation speed of the motor coincides with the controlled rotation speed. The second period includes a target reaching period corresponding to a period from the speed change timing to a target reaching timing corresponding to a timing when the control rotational speed reaches the target rotational speed by the control rotational speed setting unit.

6. The electric working machine according to claim 5, wherein: The second period also includes a period from the target attainment timing to the elapse of a waiting time.

7. The electric working machine according to any one of claims 1 to 6, wherein: The total value calculation unit is configured to calculate the total value by integrating the change amount every time the detection timing arrives during the first period.

8. The electric working machine according to any one of claims 2 to 6, wherein: The total value calculation unit is configured to calculate the total value by accumulating the change amount every time the detection timing arrives during the first period, The total value calculation unit is configured to reset the currently calculated total value based on (i) the at least one switch being manually operated and (ii) the target rotation speed being changed thereby.

9. The electric working machine according to any one of claims 2 to 8, wherein: The at least one switch comprises a first switch, The target setting unit is configured to change the target rotation speed according to a position of the first switch.

10. The electric working machine according to claim 9, wherein: The at least one switch includes a second switch, The target setting unit is configured to change the target rotation speed with a maximum rotation speed as an upper limit, and the maximum rotation speed is determined according to a position of the second switch.

11. The electric working machine according to any one of claims 1 to 10, wherein: The no-load detection requirement is satisfied based on the fact that the total value calculated by the total value calculation unit has a predetermined magnitude, and the predetermined magnitude corresponds to being equal to or less than a predetermined threshold value.

12. The electric working machine according to any one of claims 1 to 10, wherein: The no-load detection requirement is satisfied based on the fact that the total value calculated by the total value calculation unit has a predetermined magnitude, and the predetermined magnitude corresponds to or is equal to or greater than a predetermined threshold value.

13. The electric working machine according to claim 11 or 12, wherein: The no-load detection requirement is satisfied based on the fact that the total value continuation determination time calculated by the total value calculation unit is maintained at the predetermined value.

14. The electric working machine according to any one of claims 1 to 13, wherein: The first control method includes rotating the motor at a first rotation speed, wherein the first rotation speed is constant.

15. The electric working machine according to any one of claims 2 to 10, wherein: The first control method includes rotating the motor at a first rotation speed. The first rotational speed is (i) constant and (ii) lower than the target rotational speed.

16. The electric working machine according to any one of claims 1 to 15, wherein: The physical quantity includes a current flowing through the motor.

17. A motor control method, the motor control method being used in an electric working machine, The motor control method comprises the following steps: acquiring a physical quantity at each detection timing, the physical quantity being associated with an operating state of a motor provided in the electric working machine; deriving a change amount at each detection timing, the change amount corresponding to an increase from a previous physical quantity to a current physical quantity, the previous physical quantity corresponding to the physical quantity acquired at the previous detection timing, and the current physical quantity corresponding to the physical quantity acquired at the current detection timing; calculating a total value at each of the detection timings, the total value corresponding to a sum of one or more variation amounts, the one or more variation amounts respectively corresponding to the variation amounts derived at each of the detection timings in the first period; and The motor is controlled according to a control method corresponding to the sum value.

Images