Electric transport vehicle

Abstract

To enable a short-circuit brake of an electric transport vehicle to be appropriately controlled.SOLUTION: An electric transport vehicle in one aspect of the present disclosure comprises a motor and a control circuit. The motor comprises a plurality of terminals. The control circuit causes the motor to generate braking force according to a state that motor drive condition is not satisfied, through a short-circuit brake in which two or more terminals among the plurality of terminals are short-circuited each other. The control circuit gradually decreases the braking force through the short-circuit brake according to change from a state that the drive condition is not satisfied to a state that the drive condition is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electric transport vehicles. [Background technology]

[0002] Patent Document 1 discloses a hand-pushed electric cart whose wheels are driven by a motor. This hand-pushed electric cart is equipped with a mechanical brake that applies braking force directly to the wheels by friction, as well as a short-circuit brake. The short-circuit brake generates braking force in the motor by short-circuiting the motor windings. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-022338 Summary of the Invention [Problem to be solved by the invention]

[0004] The braking force of the mechanical brake can be adjusted manually by the user of the hand-pushed electric cart, while the braking force of the short-circuit brake is controlled by a microcomputer. Therefore, it is desirable to control the short-circuit brake appropriately so that the user can use the hand-pushed electric cart stably.

[0005] An object of one aspect of the present disclosure is to enable proper control of short-circuit braking in an electric transport vehicle. [Means for solving the problem]

[0006] An electric transporter in one aspect of the present disclosure includes a handle. The handle is gripped by a user of the electric transporter. The user uses the electric transporter by standing on the ground on which the electric transporter travels. The electric transporter includes a battery storage section. The battery storage section stores a battery. The electric transporter includes a motor. The motor rotates using power from the battery stored in the battery storage section. The motor has a plurality of windings and a plurality of terminals. The plurality of terminals are connected to the plurality of windings. The electric transporter includes wheels driven by the motor. The electric transporter includes a control circuit configured to control driving of the motor.

[0007] The control circuit executes a first process, which includes generating a braking force in the motor by short-circuit braking that shorts two or more of the plurality of terminals together when a drive condition for the motor is not satisfied.

[0008] The control circuit executes a second process, which includes gradually reducing the braking force of the short-circuit brake in response to a state change from a state in which the drive condition is not satisfied to a state in which the drive condition is satisfied.

[0009] Such an electric transport vehicle can properly control short circuit braking. A motor control method in another aspect of the present disclosure is used in an electric vehicle equipped with a motor. The electric vehicle includes a handle. The handle is gripped by a user of the electric vehicle. The user uses the electric vehicle by standing on a ground on which the electric vehicle travels. The electric vehicle includes wheels configured to be driven by the motor. The motor control method includes generating a braking force in the motor by a short-circuit brake that shorts two or more terminals of the motor when a driving condition of the motor is not met. The motor control method includes gradually reducing the braking force generated by the short-circuit brake when a state in which the driving condition is not met changes to a state in which the driving condition is met.

[0010] Such a motor control method can achieve the same effects as the electric transport vehicle described above. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of an electric transport vehicle according to an embodiment. [Figure 2] FIG. 1 is a bottom view of the electric truck with the loading platform removed. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is a block diagram showing the configuration of an electrical system of the electric transport vehicle. [Figure 5] FIG. 5A is a block diagram showing details of the electrical system of the operating device, and FIG. 5B is a block diagram showing details of the electrical system of the battery box, etc. [Figure 6] 10 is a flowchart of a main process. [Figure 7] 10 is a flowchart of a part of a control mode setting process. [Figure 8] 10 is a flowchart of another part of the control mode setting process. [Figure 9] 10 is a flowchart of a first release determination process. [Figure 10] 10 is a flowchart of the remaining part of the control mode setting process. [Figure 11] FIG. 11A is a flowchart of the second release determination process, and FIG. 11B is a flowchart of the braking start determination process. [Figure 12] 4 is a flowchart of an electromagnetic brake control process. [Figure 13] 10 is a flowchart of a motor control process. [Figure 14] 10 is a flowchart of a motor output control process. [Figure 15] 10 is a flowchart of a standby brake process. [Figure 16] 4 is a flowchart of a first brake process. [Figure 17] 10 is a flowchart of a second brake process. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Summary of the embodiment] In some embodiments, the electric transporter may include a handle. The handle may be configured to be gripped by a user of the electric transporter. A user may use the electric transporter by standing on the ground on which the electric transporter travels. A user may use the electric transporter by standing on the ground while gripping the handle. Here, "standing on the ground" includes remaining in a fixed position without walking, and walking or running on the ground. Additionally / alternatively, the electric transporter may include a battery housing. The battery housing may be configured to house a battery. Additionally / alternatively, the electric transporter may include a motor. The motor may be configured to rotate by power from a battery housed in the battery housing. Additionally / alternatively, the motor may have multiple windings and multiple terminals. The multiple terminals may be connected to the multiple windings. Additionally / alternatively, the electric transporter may include wheels configured to be driven by the motor. Additionally / alternatively, the electric transporter may include a control circuit configured to control driving of the motor.

[0013] The control circuit may execute a first process, which may include generating a braking force in the motor by a short-circuit brake that shorts two or more of the plurality of terminals together when a drive condition for the motor is not satisfied.

[0014] Additionally / alternatively, the control circuit may execute a second process. The second process may include gradually reducing the braking force generated by the short circuit brake in response to the occurrence of a state change. The state change corresponds to a change from a state in which the drive condition is not satisfied to a state in which the drive condition is satisfied. The second process may include gradually reducing the braking force generated by the short circuit brake from the braking force at the time the state change occurred in response to the occurrence of the state change. Additionally / alternatively, the control circuit may be configured to acquire or calculate a brake control amount that commands the braking force generated by the short circuit brake. In the first process and / or the second process, the control circuit may generate the braking force generated by the short circuit brake in accordance with the brake control amount. Additionally / alternatively, in the second process, the control circuit may set (or change) the brake control amount so that the braking force generated by the short circuit brake gradually decreases from the braking force at the time the state change occurred.

[0015] In the second process, the braking force of the short circuit brake may be reduced in any manner. For example, the braking force of the short circuit brake may be reduced stepwise or continuously. A period of stepwise reduction and a period of continuous reduction may be mixed. The reduction rate of the braking force (i.e., the rate of change) may be determined in any manner. For example, the reduction rate of the braking force may be constant or may change.

[0016] In one embodiment, an electric transport vehicle includes the handle, the battery storage unit, the motor, the wheels, and the control circuit, and the control circuit executes the first process and the second process, so that such an electric transport vehicle can properly control the short-circuit brake.

[0017] Additionally / alternatively, the control circuit may be configured to execute a third process. The third process may include releasing the short-circuit brake in response to the first condition being satisfied when the state change occurs (or when the drive condition is satisfied). Additionally / alternatively, the control circuit may set a brake control amount in the third process so that the short-circuit brake is released. When an electric vehicle in an embodiment includes the above-described control circuit, such an electric vehicle can release the short-circuit brake at an appropriate time.

[0018] The first condition may include the motor's rotation speed per unit time being equal to or greater than a first rotation speed threshold. Generally, factors that cause a motor to rotate include, for example, a first factor, a second factor, and a third factor. The first factor is torque generated by the motor itself. The second factor is rotational force due to inertia (i.e., inertia). That is, even if a motor stops generating torque while rotating, the motor usually does not immediately stop and continues to rotate by inertia (i.e., due to inertia). The third factor is an external force applied to the motor. That is, even if the motor itself is not generating torque, the motor may passively rotate when an external force is applied to the motor. In one embodiment, an electric vehicle equipped with a control circuit having the above-described features can achieve the following effects. That is, when the drive condition is met when the motor is rotating at a rotation speed equal to or greater than the first rotation speed threshold due to, for example, the second or third factor, the electric vehicle can quickly release the short-circuit brake.

[0019] Additionally / alternatively, the first process may gradually increase the braking force by the short circuit brake in response to a change from a state in which the drive condition is satisfied to a state in which the drive condition is not satisfied while the motor is rotating. Here, "while the motor is rotating" may include a state in which the motor is rotating due to any of the first, second, and third factors described above.

[0020] Additionally / alternatively, the control circuit may, in the first process, gradually increase the braking force applied by the short circuit brake from the braking force applied when the drive condition changes from a state in which it is satisfied to a state in which it is not satisfied. Additionally / alternatively, the control circuit may, in the first process, set (or change) the brake control amount so that the braking force applied by the short circuit brake gradually increases from the braking force applied when the drive condition changes from a state in which it is satisfied to a state in which it is not satisfied. Additionally / alternatively, the control circuit may, while gradually increasing the braking force applied by the short circuit brake in the first process, vary the degree of increase in consideration of the motor rotation speed or decrease the braking force depending on the situation. Alternatively, the control circuit may change (increase or decrease) the braking force applied by the short circuit brake in the first process depending on the motor rotation speed. For example, the control circuit may set a braking target rotation speed lower than the current rotation speed and generate a braking force according to the difference between the current rotation speed and the braking target rotation speed. The rotation speed may then be decreased by gradually decreasing the braking target rotation speed. As a result of changing the braking force of the short circuit brake in accordance with the rotational speed of the motor in this manner, the braking force of the short circuit brake can be gradually increased.

[0021] Additionally / alternatively, the first condition may include that the rotation speed is equal to or greater than a first rotation speed threshold, and the braking force due to the currently occurring short circuit brake is smaller than a braking force threshold. In one embodiment, when an electric cart is equipped with a control circuit having the above-described characteristics, such an electric cart can suppress fluctuations in rotation speed when switching between a state in which the drive conditions are met and a state in which the drive conditions are not met.

[0022] Additionally / alternatively, the control circuit may be configured to execute a fourth process. The fourth process may include releasing the short circuit brake in response to the second condition being satisfied after the state change occurs (or after the drive condition is satisfied). Additionally / alternatively, in the fourth process, the control circuit may set (or change) the brake control amount so that the short circuit brake is released (or so that the braking force due to the short circuit brake becomes zero). When an electric vehicle in an embodiment includes the above control circuit, such an electric vehicle can release the short circuit brake at an appropriate timing after the drive condition is satisfied.

[0023] The second condition may be satisfied when the third condition is satisfied. The third condition may be satisfied when the rotation speed remains equal to or less than the second rotation speed threshold for a first period of time from a first timing after the state change occurs (or after the drive condition is satisfied). The second rotation speed threshold may be zero. The satisfaction of the third condition may mean, for example, that the electric vehicle is on flat ground or a gently sloping surface. In such cases, the electric vehicle is unlikely to accelerate unintentionally when the short-circuit brake is released. Therefore, when an electric vehicle in one embodiment includes a control circuit having the above-described characteristics, the electric vehicle can release the short-circuit brake at an appropriate timing depending on the state of the electric vehicle.

[0024] Additionally / alternatively, the second condition may be met when the third condition is met after the fourth condition is met. The fourth condition may be met when a second time period has elapsed since a second timing after a state change occurs (or after the drive condition is met). The first timing may occur after the fourth condition is met. In one embodiment, when an electric vehicle is equipped with a control circuit having the above-described characteristics, the electric vehicle can appropriately determine whether the third condition is met.

[0025] Additionally / alternatively, the control circuit may execute a direction setting process to set the rotation direction of the motor. Additionally / alternatively, the control circuit may execute a motor control process. The motor control process may include controlling the motor so that it rotates in a set rotation direction. The set rotation direction may be the rotation direction set by the direction setting process. Additionally / alternatively, the second condition may be met when the fifth condition is met. The fifth condition may be met when the motor rotates in a direction opposite to the set rotation direction. The fifth condition being met may indicate, for example, a situation in which the electric vehicle is traveling uphill and attempting to ascend the uphill slope after the short circuit brake has been released. Furthermore, a situation in which the braking force of the short circuit brake decreases and the electric vehicle begins to move downward due to gravity may be anticipated. In such a case, it may be desirable to release the short circuit brake early and control the motor so that it rotates in the set rotation direction. Therefore, when an electric vehicle in one embodiment includes a control circuit having the above-described features, the electric vehicle can release the short circuit brake at an appropriate timing depending on the state of the electric vehicle.

[0026] Additionally / alternatively, the second condition may be satisfied in response to the fifth condition being satisfied after the fourth condition is satisfied. In an embodiment, when an electric vehicle includes a control circuit having the above-described features, the electric vehicle can appropriately determine whether the fifth condition is satisfied.

[0027] Additionally / alternatively, the electric vehicle may include a manual operation receiving unit. The manual operation receiving unit may be configured to instruct the control circuit to drive the motor in response to receiving a first manual operation by a user. The drive condition may be established in response to receiving the first manual operation by the manual operation receiving unit. In an embodiment, when an electric vehicle includes the manual operation receiving unit and a control circuit having the above characteristics, the electric vehicle can gradually start reducing the braking force of the short-circuit brake at an appropriate timing in response to the user's intention to drive the motor.

[0028] Additionally / alternatively, the electric transporter may include wheels configured to be driven by a motor. Additionally / alternatively, the electric transporter may include a mechanical brake. The mechanical brake may receive a second manual operation by a user. Additionally / alternatively, the mechanical brake may be configured to directly brake the rotation of the wheels in accordance with the amount of operation of the second manual operation. Additionally / alternatively, the drive condition may be established in response to the manual operation receiving unit receiving a first manual operation and the braking by the mechanical brake being released. In an embodiment, when an electric transporter includes the above-described mechanical brake and a control circuit having the above-described features, such an electric transporter can gradually start reducing the braking force of the short-circuit brake at a more appropriate timing in accordance with the user's intention.

[0029] Additionally / alternatively, the electric vehicle may include an electromagnetic brake. The electromagnetic brake may include an electromagnet. Additionally / alternatively, the electromagnetic brake may be configured to brake or release the motor using a magnetic force generated by the electromagnet. Additionally / alternatively, the control circuit may execute an electromagnetic brake process. The electromagnetic brake process may include braking the motor using the electromagnetic brake when the drive conditions are not met. When an electric vehicle in an embodiment includes the above-described electromagnetic brake and control circuit, such an electric vehicle can more appropriately brake the electric vehicle when the drive conditions are not met.

[0030] Additionally / alternatively, the electromagnetic brake process may include braking the motor with an electromagnetic brake when the drive condition is not satisfied and the number of rotations per unit time of the motor is equal to or less than a third rotation speed threshold. The third rotation speed threshold may be any value. For example, the third rotation speed threshold may be a value close to 0 or may be 0.

[0031] Additionally / alternatively, the control circuit may further execute a brake release process. The brake release process may include releasing the braking of the motor by the electromagnetic brake in response to the occurrence of a state change (or the establishment of a drive condition). When an electric vehicle is equipped with the above control circuit in an embodiment, the electric vehicle can suppress unintended behavior of the electric vehicle immediately after the electromagnetic brake is released.

[0032] The multiple terminals may include three terminals. Additionally / alternatively, the motor may be configured to rotate when three-phase power is supplied to the three terminals. The short-circuit brake for the motor when stopped may include a three-phase short-circuit brake that generates a braking force on the motor by short-circuiting the three terminals together. When an electric transport vehicle in one embodiment includes the motor described above and a control circuit having the above features, the electric transport vehicle can increase the braking force provided by the short-circuit brake. Note that the control circuit may apply the three-phase short-circuit brake, for example, continuously or intermittently, when the motor is stopped.

[0033] Additionally / alternatively, short-circuit braking of a rotating motor may include continuously or intermittently applying a two-phase short-circuit brake that generates a braking force on the motor by short-circuiting two of three terminals, intermittently applying a three-phase short-circuit brake that generates a braking force on the motor by short-circuiting three terminals, and / or selectively switching between applying a two-phase short-circuit brake and a three-phase short-circuit brake. When an electric vehicle in an embodiment includes a control circuit having the above-described features, such an electric vehicle can efficiently control the braking force by short-circuit braking. Note that, when the motor is rotating, for example, only the two-phase short-circuit brake may be applied continuously or intermittently, or the three-phase short-circuit brake and the two-phase short-circuit brake may be applied by alternately switching between them. There may be a period during which the brake is not applied during the process of switching between the three-phase short-circuit brake and the two-phase short-circuit brake.

[0034] In an embodiment, the motor control method may be used in an electric vehicle equipped with a motor. The electric vehicle may include a handle. The handle may be configured to be gripped by a user of the electric vehicle. The user may use the electric vehicle by standing on the ground on which the electric vehicle travels. Additionally / alternatively, the electric vehicle may include wheels configured to be driven by the motor. The motor control method may include, in response to a drive condition of the motor not being satisfied, generating a braking force in the motor by a short-circuit brake that short-circuits two or more of a plurality of terminals of the motor. Additionally / alternatively, the motor control method may include gradually reducing the braking force generated by the short-circuit brake in response to a change from a state in which the drive condition is not satisfied to a state in which the drive condition is satisfied.

[0035] When a motor control method in an embodiment includes all of the above steps, such a motor control method can properly control the short circuit brake of an electric transport vehicle. In some embodiments, the above features may be combined in any combination. In some embodiments, any of the above features may be omitted.

[0036] Specific Exemplary Embodiments (1) Overview of the transport vehicle As shown in Figures 1 and 2, the electric cart 1 of this embodiment includes a main body 2, one or more front wheels, and one or more rear wheels. In this embodiment, the one or more front wheels include, for example, two front wheels 8 and 9, and the one or more rear wheels include, for example, two rear wheels 10 and 11. In other words, the electric cart 1 of this embodiment has the form of a four-wheeled vehicle.

[0037] In this embodiment, for example, the front wheels 8 and 9 correspond to drive wheels, and the rear wheels 10 and 11 correspond to driven wheels. That is, the front wheels 8 and 9 are driven (i.e., rotated) by a motor 25 (see FIG. 4) described later.

[0038] A loading platform 3 is fixed to the main body 2. The loading platform 3 is detachable from the main body 2. Various types of cargo can be placed on the loading platform 3. A user of the electric vehicle 1 can transport the cargo by placing the cargo on the loading platform 3 and driving the electric vehicle 1. The user can selectively fasten one of several types of loading platforms 3 to the main body 2.

[0039] The electric cart 1 further includes a motor unit 20 as shown in FIGS. 2 and 3. The motor unit 20 houses a motor 25 (see FIGS. 3 and 4). The electric cart 1 further includes an electromagnetic brake 30 as shown in FIGS. 3 and 4. In this embodiment, the electromagnetic brake 30 is housed in the motor unit 20, for example.

[0040] 3, the motor 25 includes a motor stator 26, a motor rotor 27, and a motor shaft 28. The motor rotor 27 includes, for example, a permanent magnet. The motor shaft 28 is fixed to the motor rotor 27. When the motor rotor 27 rotates, the motor shaft 28 rotates accordingly.

[0041] As shown in Fig. 4, the motor 25 further includes a first terminal 25u, a second terminal 25v, and a third terminal 25w. The motor 25 of this embodiment is, for example, a three-phase brushless motor. The motor stator 26 includes a first winding 25a, a second winding 25b, and a third winding 25c. The first to third windings 25a to 25c are, for example, delta-connected. The first to third windings 25a to 25c may be connected to each other in any manner. For example, the first to third windings 25a to 25c may be star-connected to each other.

[0042] The first to third windings 25a to 25c are electrically connected to the first to third terminals 25u to 25w. When power is supplied to the first to third windings 25a to 25c via the first to third terminals 25u to 25w, the motor rotor 27 rotates (and thus the motor shaft 28 rotates). The rotation of the motor shaft 28 is transmitted to the transmission mechanism 21. In this embodiment, the term "rotation" for the motor 25 specifically refers to the rotation of the motor shaft 28.

[0043] The electric transporter 1 further includes a transmission mechanism 21. The transmission mechanism 21 transmits the rotation of the motor 25 to the front wheels 8, 9. More specifically, the transmission mechanism 21 transmits the rotation of the motor 25 to the right front wheel 8 via a right drive shaft 22, and to the left front wheel 9 via a left drive shaft 23. The transmission mechanism 21 may include, for example, a differential gear.

[0044] As shown in FIG. 2 , the electric transporter 1 further includes a mechanical brake 24. The mechanical brake 24 brakes the rotation of the front wheels 8, 9 by frictional force. In this embodiment, the mechanical brake 24 includes, for example, a right disc brake 24a and a left disc brake 24b. The right disc brake 24a brakes the rotation of the right front wheel 8. That is, the right disc brake 24a includes a brake disc that rotates integrally with the right front wheel 8. The left disc brake 24b includes a brake disc that rotates integrally with the left front wheel 9. When the mechanical brake 24 is activated, the brake pads clamp each brake disc, thereby braking the front wheels 8, 9.

[0045] 3, the electromagnetic brake 30 of this embodiment includes, for example, a brake stator 31, a brake plate 32, an armature 33, and a brake rotor 34. An electromagnetic coil (not shown) is built into the brake stator 31. The brake stator 31 and the brake plate 32 are fixed within the motor unit 20.

[0046] The brake rotor 34 is fixed to the motor shaft 28. When the motor shaft 28 rotates, the brake rotor 34 also rotates. The armature 33 is elastically supported so as to be movable in a direction perpendicular to the rotation plane of the brake rotor 34 (i.e., a direction parallel to the axial direction of the motor shaft 28).

[0047] When the electromagnetic brake 30 is turned on, the armature 33 is displaced toward the brake plate 32. As a result, the brake rotor 34 is sandwiched between the armature 33 and the brake plate 32, and the rotation of the brake rotor 34 is braked. In other words, the rotation of the motor shaft 28 is braked.

[0048] When the electromagnetic brake 30 is turned off (i.e., released), the armature 33 is displaced in a direction away from the brake plate 32. As a result, the brake rotor 34 is no longer in contact with the armature 33 and the brake plate 32, and the braking force of the electromagnetic brake 30 is no longer applied to the motor shaft 28.

[0049] In this embodiment, for example, when power is supplied to the electromagnetic coil in the brake stator 31, the electromagnetic coil functions as an electromagnet. This turns off the electromagnetic brake 30, and braking force is no longer applied. On the other hand, when the power supply to the electromagnetic coil is cut off, the electromagnetic brake 30 turns on, and braking force is applied.

[0050] In this embodiment, the traveling of the electric transporter 1 can be braked by a short-circuit brake in addition to the mechanical brake 24 and the electromagnetic brake 30. The short-circuit brake includes a three-phase short-circuit brake and a two-phase short-circuit brake.

[0051] The three-phase short circuit brake corresponds to short-circuiting the first to third terminals 25u to 25w of the motor 25 with each other. The two-phase short-circuit brake corresponds to shorting any two of the first to third terminals 25u to 25w to each other. The two terminals that are shorted to each other in the two-phase short-circuit brake are determined by which of the first to third windings 25a to 25c an induced voltage is generated by the rotation of the motor rotor 27. In other words, the two terminals are short-circuited so that a current based on the induced voltage flows in the winding in which the induced voltage is generated (and so that a braking torque is generated in the motor rotor 27 due to the electromagnetic interaction between the current and the motor rotor 27). Hereinafter, the current based on the induced voltage that flows from the winding in which the induced voltage is generated via the two terminals will be referred to as the "two-phase short-circuit current."

[0052] The braking force of a three-phase short-circuit brake is greater than that of a two-phase short-circuit brake, which can be controlled by adjusting the time the two terminals are short-circuited, in other words, by adjusting the effective value of the two-phase short-circuit current.

[0053] The main body 2 includes a right handlebar 12 and a left handlebar 13. The right handlebar 12 and the left handlebar 13 each have a rod-like shape, for example, bent into an L shape. A right grip 12a is provided at a first end of the right handlebar 12. A left grip 13a is provided at a first end of the left handlebar 13. The right grip 12a is held, for example, by the user's right hand. The left grip 13a is held, for example, by the user's left hand.

[0054] The main body 2 is provided with a brake lever 13b. The brake lever 13b is provided, for example, near the left grip 13a on the left handlebar 13. For example, a user can operate the brake lever 13b with their left hand while holding the left grip 13a with their left hand. When the brake lever 13b is operated, the mechanical brake 24 is activated, and a braking force by the mechanical brake 24 is applied to the front wheels 8, 9. The braking force by the mechanical brake 24 changes depending on the amount of operation of the brake lever 13b by the user.

[0055] The main body 2 includes an operating device 14. The operating device 14 is provided, for example, near the right grip 12a on the right handlebar 12. The electrical configuration of the operating device 14 will be described later with reference to Fig. 5A.

[0056] The main body 2 includes a drive lever 14a. In this embodiment, the drive lever 14a is provided, for example, on the operating device 14. For example, a user can operate (e.g., pull) the drive lever 14a with their right hand while holding the right grip 12a with their right hand.

[0057] The main body 2 includes a battery box 15. The battery box 15 is disposed, for example, between the right handlebar 12 and the left handlebar 13. A plurality of battery packs are removably attached to the battery box 15. In this embodiment, for example, a first battery pack 61 and a second battery pack 62 (see FIG. 4) can be individually attached to the battery box 15. Other electrical configurations of the battery box 15 will be described later with reference to FIG. 5B.

[0058] A user can push or pull the electric cart 1 by himself or herself to rotate the front wheels 8, 9 and rear wheels 10, 11 and move the electric cart 1. In addition, by operating the drive lever 14a, the user can drive the front wheels 8, 9 with the motor 25, and move the electric cart 1 by the driving force.

[0059] (2) Electrical configuration of the electric transport vehicle As shown in Fig. 4, the electric cart 1 includes a first controller 50. The first controller 50 controls the driving of the motor 25. The electric cart 1 further includes a second controller 70. The second controller 70 controls the electromagnetic brake 30.

[0060] The first controller 50 includes a control circuit 51. The control circuit 51 includes, for example, a CPU 51a and a memory 51b. The memory 51b may include, for example, a semiconductor memory such as a ROM, a RAM, an NVRAM, or a flash memory. That is, the first controller 50 of this embodiment includes a microcomputer.

[0061] The control circuit 51 realizes various functions by executing a program stored in a non-transient physical recording medium. In this embodiment, the memory 51b corresponds to the non-transient physical recording medium storing the program. In this embodiment, the memory 51b stores a program for main processing (see FIG. 6) described later.

[0062] Some or all of the various functions realized by the control circuit 51 may be achieved by executing a program (i.e., by software processing), or may be achieved by one or more pieces of hardware. For example, instead of or in addition to a microcomputer, the control circuit 51 may include a logic circuit including multiple electronic components, an application specific integrated circuit such as an ASIC and / or ASSP, or a programmable logic device such as an FPGA that can configure any logic circuit.

[0063] 4 illustrates a state in which both the first battery pack 61 and the second battery pack 62 described above are attached to the battery box 15. The first battery pack 61 and the second battery pack 62 each function as a power source for the electric transporter 1. The first battery pack 61 includes a first battery 61a. The second battery pack 62 includes a second battery 62a. The first battery 61a and / or the second battery 62a may be, for example, a secondary battery.

[0064] The electric transporter 1 is equipped with a battery selector switch 81. In this embodiment, the battery selector switch 81 is provided in, for example, the battery box 15. The battery selector switch 81 sets the power source for the motor 25 to either the first battery pack 61 or the second battery pack 62 in response to operation by the user. The battery selector switch 81 outputs a battery selector switch signal to the control circuit 51. The battery selector switch signal indicates the battery pack selected by the battery selector switch 81.

[0065] The electric transporter 1 includes a key insertion unit 63. The key insertion unit 63 is connected to the battery selector switch 81 and the first controller 50 (a trigger switch 102, which will be described in detail later). The key insertion unit 63 is configured so that the key can be inserted in a removable manner.

[0066] When a key is inserted into the key insertion portion 63, the key insertion portion 63 electrically connects the battery selector switch 81 and the first controller 50 via the key insertion portion 63. In this case, power from either the first battery pack 61 or the second battery pack 62 selected by the battery selector switch 81 is input to the first controller 50 via the battery selector switch 81 and the key insertion portion 63. This power will be referred to hereinafter as "motor drive power."

[0067] When no key is inserted into the key insertion portion 63, the key insertion portion 63 cuts off the electrical connection between the battery selector switch 81 and the first controller 50 via the key insertion portion 63. In this case, motor drive power is not input to the first controller 50. Note that the following explanation is based on the premise that a key is inserted into the key insertion portion 63, i.e., that the first controller 50 is in a state where motor drive power is input.

[0068] The first controller 50 includes a first gate circuit 53. The control circuit 51 outputs a plurality of motor control signals to the first gate circuit 53. The motor control signals are signals that control the rotation of the motor 25. In this embodiment, each of the motor control signals is, for example, a pulse width modulation signal (PWM signal). While the trigger switch 102 is turned on, motor drive power is input to the first gate circuit 53 via the trigger switch 102. The first gate circuit 53 uses the motor drive power to generate a plurality of drive signals corresponding to each of the motor control signals. The drive signals are generated, for example, by boosting the motor control signals using the motor drive power.

[0069] The first controller 50 includes a drive circuit 52. A drive signal generated by a first gate circuit 53 is input to the drive circuit 52. Motor drive power is input to the drive circuit 52 via a trigger switch 102. More specifically, the first controller 50 of this embodiment includes a regeneration suppression circuit 54, and motor drive power is input to the drive circuit 52 via the trigger switch 102 and the regeneration suppression circuit 54.

[0070] The drive circuit 52 is connected to the first to third terminals 25u to 25w of the motor 25. The drive circuit 52 generates three-phase drive power for driving the motor 25 from the input motor drive power, and supplies the three-phase drive power to the motor 25 (specifically, the first to third terminals 25u to 25w).

[0071] The drive circuit 52 of this embodiment includes a three-phase full-bridge circuit. The three-phase full-bridge circuit includes a first switch element Q1, a second switch element Q2, a third switch element Q3, a fourth switch element Q4, a fifth switch element Q5, and a sixth switch element Q6. Each of the first to sixth switch elements Q1 to Q6 may be any type of switch element. In this embodiment, each of the first to sixth switch elements Q1 to Q6 is, for example, an n-channel metal oxide semiconductor field effect transistor (MOSFET).

[0072] The drive signals output from the first gate circuit 53 are input to the first to sixth switch elements Q1 to Q6, respectively. The first to sixth switch elements Q1 to Q6 are turned on or off according to the input drive signals. As described above, the motor control signals in this embodiment are PWM signals. Therefore, each of the first to sixth switch elements Q1 to Q6 is turned on periodically according to the duty ratio of the corresponding drive signal (and therefore the duty ratio of the corresponding motor control signal).

[0073] The above-mentioned three-phase short circuit braking is performed, for example, by turning on three of the first to sixth switch elements Q1 to Q6 on the so-called low side (fourth to sixth switch elements Q4 to Q6) and turning off the other three on the high side (first to third switch elements Q1 to Q3).

[0074] The two-phase short circuit braking is performed by, for example, turning on any two of the fourth to sixth switch elements Q4 to Q6 on the low side and turning off the other four switch elements. The two switch elements that are turned on in the two-phase short circuit braking are set so that the two-phase short circuit current flows through the two switch elements.

[0075] The regeneration suppression circuit 54 is provided in the motor drive power supply path that runs from the trigger switch 102 to the drive circuit 52. The regeneration suppression circuit 54 suppresses regenerative current from flowing from the motor 25 to the selected battery via the drive circuit 52. The selected battery corresponds to either the first battery pack 61 or the second battery pack 62 selected by the battery selector switch 81.

[0076] The regeneration suppression circuit 54 of this embodiment includes two switch elements Q7 and Q8 connected in series. The switch elements Q7 and Q8 are, for example, n-channel MOSFETs. The gate and source of each of the switch elements Q7 and Q8 are short-circuited to each other. The regenerative current from the motor 25 is suppressed by a parasitic diode included in each of the switch elements Q7 and Q8.

[0077] The first controller 50 also includes a current detection circuit 55. The current detection circuit 55 detects the value of the current flowing through the motor 25 (hereinafter referred to as the "motor current value"). The current detection circuit 55 outputs a current detection signal to the control circuit 51. The current detection signal includes information indicating the motor current value. In this embodiment, the current detection circuit 55 is provided between the drive circuit 52 and a ground line. The ground line is connected to the negative electrodes of the first and second batteries 61a and 62a.

[0078] As shown in FIG. 4, the motor 25 is provided with a rotation sensor 64. The rotation sensor 64 outputs a rotation detection signal indicating the rotation of the motor 25 to the first controller 50 (more specifically, the control circuit 51). In this embodiment, the rotation sensor 64 includes, for example, a Hall sensor. The rotation detection signal includes a pulse signal. The rotation sensor 64 outputs a pulse signal each time the motor 25 rotates a certain angle. The control circuit 51 can detect that the motor 25 is rotating in response to receiving the pulse signal. The control circuit 51 can also detect the motor rotation speed based on the reception interval of the pulse signal. The motor rotation speed is the number of rotations per unit time of the motor 25. In other words, the motor rotation speed corresponds to the speed (rotational speed) of the motor 25. The control circuit 51 can also detect the rotation direction of the motor 25 based on changes in the reception timing of the pulse signal.

[0079] As shown in FIG. 4, the electric cart 1 is equipped with a mechanical brake switch 60. The mechanical brake switch 60 is turned on or off in conjunction with the brake lever 13b. Specifically, the mechanical brake switch 60 is turned on while the brake lever 13b is being operated. The mechanical brake switch 60 outputs a mechanical brake switch signal to the control circuit 51. The mechanical brake switch signal indicates whether the mechanical brake switch 60 is turned on or off.

[0080] As shown in Fig. 4, the electric cart 1 includes the aforementioned operating device 14. The operating device 14 is electrically connected to the first controller 50 (more specifically, the control circuit 51). The electric cart 1 includes the aforementioned battery box 15. The battery box 15 is electrically connected to the first controller 50 (more specifically, the control circuit 51). The battery box 15 is further electrically connected to a first battery pack 61 and a second battery pack 62.

[0081] The operation device 14 will be described in detail with reference to FIG. 5A. The operation device 14 includes a main power switch 101. The main power switch 101 is configured to be turned on (e.g., pressed down) by a user. The main power switch 101 may be, for example, a tactile switch. The main power switch 101 outputs a main power switch signal to the control circuit 51. The main power switch signal indicates whether the main power switch 101 is turned on or not.

[0082] The operating device 14 includes a trigger switch 102. The trigger switch 102 is turned on or off in conjunction with the drive lever 14a. Specifically, the trigger switch 102 is turned on while the drive lever 14a is being operated. The trigger switch 102 outputs a trigger switch signal to the control circuit 51. The trigger switch signal indicates whether the trigger switch 102 is turned on or off. For ease of explanation, the trigger switch 102 is illustrated in FIG. 4 within a dashed-line frame that indicates the first controller 50.

[0083] The operating device 14 includes a pull amount detection unit 103. The pull amount detection unit 103 detects the pull amount of the drive lever 14a. The pull amount detection unit 103 outputs a pull amount detection signal to the control circuit 51. The pull amount detection signal indicates the pull amount detected by the pull amount detection unit 103.

[0084] The operating device 14 includes a direction changeover switch 104. The direction changeover switch 104 is turned on (e.g., pressed down) by the user to set the traveling direction of the electric cart 1 to either forward or reverse. The direction changeover switch 104 outputs a direction changeover switch signal to the control circuit 51. The direction changeover switch signal indicates whether the direction changeover switch 104 is turned on or not. The control circuit 51 alternately switches the traveling direction of the electric cart 1 (more specifically, the rotation direction of the motor 25) each time the direction changeover switch 104 is turned on (more specifically, each time it changes from off to on). The rotation direction of the motor 25 set by the control circuit 51 in response to the direction changeover switch signal will hereinafter be referred to as the set rotation direction.

[0085] The operating device 14 includes a direction display unit 106. The control circuit 51 outputs a direction display signal indicating the set traveling direction to the direction display unit 106. The direction display unit 106 displays the traveling direction of the electric transporter 1 in accordance with the direction display signal input from the control circuit 51.

[0086] The operating device 14 includes a speed changeover switch 105. The speed changeover switch 105 is turned on (e.g., pressed down) by the user to set the speed mode of the motor 25 to one of a plurality of modes. In this embodiment, the speed mode is set to, for example, one of high-speed mode, medium-speed mode, and low-speed mode. The speed changeover switch 105 outputs a speed changeover switch signal to the control circuit 51. The speed changeover switch signal indicates whether the speed changeover switch 105 is turned on. The control circuit 51 sequentially switches the speed mode each time the speed changeover switch 105 is turned on (more specifically, each time it changes from off to on).

[0087] The operating device 14 includes a speed display unit 107. The control circuit 51 outputs a speed display signal indicating the set speed mode to the speed display unit 107. The speed display unit 107 displays the speed mode of the electric transporter 1 in accordance with the speed display signal input from the control circuit 51.

[0088] The battery box 15 will be specifically described with reference to Fig. 5B. The battery box 15 includes the battery changeover switch 81 described above. Furthermore, the battery box 15 includes a remaining capacity display switch 82. The control circuit 51 is configured to detect the remaining capacity of each of the first battery 61a and the second battery 62a. The remaining capacity display switch 82 is turned on (e.g., pressed down) by the user to display the remaining capacity of each of the first battery 61a and the second battery 62a. The remaining capacity display switch 82 outputs a remaining capacity display switch signal to the control circuit 51. The remaining capacity display switch signal indicates whether the remaining capacity display switch 82 is turned on.

[0089] The battery box 15 also includes a first remaining capacity display unit 83 and a second remaining capacity display unit 84. Every time the control circuit 51 recognizes that the remaining capacity display switch 82 has been turned on based on the remaining capacity display switch signal, the control circuit 51 displays the remaining capacity of the first battery 61a on the first remaining capacity display unit 83 and the remaining capacity of the second battery 62a on the second remaining capacity display unit 84.

[0090] The battery box 15 also includes a first voltage detection unit 85. The first voltage detection unit 85 detects the voltage output from the first battery pack 61, i.e., the output voltage V1 of the first battery 61a. The first voltage detection unit 85 outputs a first voltage signal to the control circuit 51. The first voltage signal includes information indicating the output voltage V1.

[0091] The battery box 15 also includes a second voltage detection unit 86. The second voltage detection unit 86 detects the value of the voltage output from the second battery pack 62, i.e., the output voltage V2 of the second battery 62a. The second voltage detection unit 86 outputs a second voltage signal to the control circuit 51. The second voltage signal includes information indicating the output voltage V2.

[0092] The battery box 15 also includes a first communication unit 87. The first communication unit 87 relays communication between the first battery pack 61 and the control circuit 51. The first communication unit 87 outputs first communication information indicating data received from the first battery pack 61 to the control circuit 51.

[0093] The battery box 15 also includes a second communication unit 88. The second communication unit 88 relays communication between the second battery pack 62 and the control circuit 51. The second communication unit 88 outputs second communication information indicating data received from the second battery pack 62 to the control circuit 51.

[0094] 4, the first controller 50 includes a first regulator 57. The first regulator 57 receives an output voltage V1 from a first battery pack 61 via a first diode D1. The first regulator 57 also receives an output voltage V2 from a second battery pack 62 via a second diode D2.

[0095] The first regulator 57 generates a first control voltage Vc1 from the output voltage V1 and / or the output voltage V2 input to the first regulator 57. The first control voltage Vc1 is supplied to the control circuit 51 and its peripheral circuits.

[0096] The first regulator 57 receives a power supply control signal from the control circuit 51. The power supply control signal indicates on or off. In response to the power supply control signal indicating on being input, the first regulator 57 generates a first control voltage Vc1. In response to the power supply control signal indicating off being input, the first regulator 57 stops generating the first control voltage Vc1. Therefore, by outputting a power supply control signal indicating off, the control circuit 51 can stop the output of the first control voltage Vc1 from the first regulator 57 and stop the operation of the control circuit 51 itself.

[0097] The first regulator 57 generates the first control voltage Vc1 in response to receiving a startup trigger while generation of the first control voltage Vc1 is stopped. The startup trigger includes, for example, turning on the main power switch 101 and / or turning on the remaining power indicator switch 82. When the power supply voltage Vcc is generated by the startup trigger, the control circuit 51 starts up.

[0098] The second controller 70 receives the output voltage V1 of the first battery pack 61 and / or the output voltage V2 of the second battery pack 62. The second controller 70 is also connected to the control circuit 51 and the electromagnetic brake 30.

[0099] The second controller 70 includes a switch element Q9. In this embodiment, the switch element Q9 is, for example, an n-channel MOSFET. The output voltage V1 and / or the output voltage V2 is input to the drain of the switch element Q9. The source of the switch element Q9 is connected to the electromagnetic brake 30. More specifically, the source of the switch element Q9 is connected to a first end of the electromagnetic coil in the electromagnetic brake 30. The second end of the electromagnetic coil is connected to the ground line. The second controller 70 further includes a fifth diode D5. The anode of the fifth diode D5 is connected to the ground line. The cathode of the fifth diode D5 is connected to the source of the switch element Q9.

[0100] When switch element Q9 is turned on, output voltage V1 and / or output voltage V2 is output to electromagnetic brake 30 via switch element Q9. This turns off electromagnetic brake 30, and braking of motor 25 by electromagnetic brake 30 is released. When switch element Q9 is turned off, neither output voltage V1 nor output voltage V2 is output to electromagnetic brake 30. In this case, electromagnetic brake 30 is turned on, and motor 25 is braked.

[0101] The second controller 70 includes a signal determination circuit 71. The signal determination circuit 71 receives an electromagnetic brake control signal from the control circuit 51. In this embodiment, the electromagnetic brake control signal is, for example, a binary signal. That is, the electromagnetic brake control signal indicates whether the electromagnetic brake 30 should be turned on or off. The signal determination circuit 71 determines whether the electromagnetic brake control signal indicates on or off, and outputs a determination signal indicating the determination result.

[0102] The second controller 70 includes a second gate circuit 72. A determination signal is input to the second gate circuit 72 from the signal determination circuit 71. The second gate circuit 72 turns switch element Q9 on or off in accordance with the input determination signal. Specifically, when the determination signal indicates that the electromagnetic brake 30 is on, the second gate circuit 72 turns switch element Q9 off to prevent power from being supplied to the electromagnetic brake 30. On the other hand, when the determination signal indicates that the electromagnetic brake 30 is off, the second gate circuit 72 turns switch element Q9 on to release the braking effect of the electromagnetic brake 30.

[0103] The second controller 70 includes a second regulator 73. The output voltage V1 of the first battery pack 61 is input to the regulator 73 via a third diode D3. The output voltage V2 of the second battery pack 62 is also input to the regulator 73 via a fourth diode D4.

[0104] The regulator 73 generates a second control voltage Vc2 from the output voltage V1 and / or the output voltage V2 input to the regulator 73. The second control voltage Vc2 is supplied to the signal determination circuit 71 and the second gate circuit 72.

[0105] 4 schematically shows that the rotation of motor 25 is transmitted to front wheels 8, 9 via transmission mechanism 21. FIG. 4 also schematically shows that the rotation of motor 25 can be braked by electromagnetic brake 30, and that the rotation of front wheels 8, 9 can be braked by mechanical brake 24.

[0106] (3) Overview of motor control An overview of a method for controlling the motor 25 by the control circuit 51 will be described. The control circuit 51 of this embodiment has, for example, five types of control modes. The control circuit 51 sets the control circuit 51 to one of the five types of control modes. The five types of control modes include an initial mode, a standby mode, a first braking mode, a second braking mode, and a driving mode. In the following description, "brake mode" means the first braking mode and / or the second braking mode.

[0107] When the electric transporter 1 is stopped and the motor drive condition is not satisfied, the control circuit 51 basically sets the control mode to the standby mode. The motor drive condition may be satisfied in any case. In this embodiment, the motor drive condition is satisfied, for example, when the trigger switch 102 is turned on (i.e., the drive lever 14a is operated) and the mechanical brake switch 60 is turned off (i.e., the brake lever 13b is not operated). Note that the motor drive condition may also be satisfied, for example, when the trigger switch 102 is turned on. Alternatively, for example, the motor drive condition may be satisfied when one or more other conditions are satisfied in addition to the trigger switch 102 being turned on and the mechanical brake switch 60 being turned off.

[0108] The control circuit 51, which is set to the standby mode, turns on the electromagnetic brake and applies the three-phase short-circuit brake. That is, the control circuit 51 brakes the motor 25 by operating the three-phase short-circuit brake (i.e., by short-circuiting the first to third terminals 25u to 25w with each other).

[0109] The control circuit 51 may set the control mode to the standby mode when the electric transport vehicle 1 is traveling (i.e., when the motor 25 is rotating). In this case, the control circuit 51 turns off the electromagnetic brake and applies the two-phase short-circuit brake.

[0110] The control circuit 51, which has been set to standby mode, switches the control mode to brake mode when the motor drive conditions are met. In brake mode, the control circuit 51 turns off the electromagnetic brake and switches the short-circuit brake to a two-phase short-circuit brake. Furthermore, the control circuit 51 gradually reduces the braking force of the two-phase short-circuit brake. By turning off the electromagnetic brake while maintaining the short-circuit brake, for example, when the electric vehicle 1 is on a downhill slope, the electric vehicle 1 is prevented from accelerating downward due to gravity.

[0111] However, to improve the user experience (restartability) when a retrigger operation is performed, the control circuit 51 immediately releases the short-circuit brake if the first condition is met when the motor drive condition is met. Specifically, the short-circuit brake is quickly released by immediately switching the control mode to the drive mode. In this case, the control circuit 51 may switch the control mode from the standby mode to the drive mode without switching the control mode from the brake mode, or may temporarily set the control mode to the brake mode and then immediately switch to the drive mode.

[0112] The control circuit 51 set to the drive mode drives the motor 25 by supplying three-phase drive power to the motor 25. The control circuit 51 set to the drive mode monitors the motor rotation speed and controls the motor 25 so that the motor rotation speed matches a target rotation speed. The control circuit 51 may monitor the motor current value in addition to the motor rotation speed and control the motor 25 according to the monitoring results. The control circuit 51 may switch the control mode from the drive mode to the brake mode according to the monitoring results.

[0113] The first condition may be satisfied in any case. In this embodiment, the first condition is satisfied, for example, when the motor rotation speed is equal to or greater than the first rotation speed threshold R1 and the brake control amount is equal to or less than the control amount threshold M1 [%].

[0114] The brake control amount determines the braking force of the two-phase short-circuit brake. In this embodiment, the brake control amount can take a value within a range of 0% to 100%, for example. The control circuit 51 calculates the brake control amount based on the motor rotation speed and the brake command rotation speed described below. The control circuit 51 applies the two-phase short-circuit brake according to the calculated brake control amount. When the brake control amount is 0%, the control circuit 51 sets the braking force of the two-phase short-circuit brake to zero. In other words, in this case, the two-phase short-circuit brake is not activated. When the brake control amount is 100%, the control circuit 51 maximizes the braking force of the two-phase short-circuit brake. The control circuit 51 applies the two-phase short-circuit brake so that the braking force of the two-phase short-circuit brake increases as the brake control amount increases.

[0115] The control amount threshold M1 may be set to any value. For example, the control amount threshold M1 may be set to any value equal to or less than 50%. For example, the control amount threshold M1 may be set to 25%.

[0116] The control circuit 51, which has been set to the brake mode, sets the control mode to the drive mode in response to the second condition being satisfied. The second condition may be satisfied in any case. In this embodiment, the second condition is satisfied, for example, in response to the condition B or the condition C being satisfied after the condition A is satisfied.

[0117] Condition A (corresponding to an example of the fourth condition in the present disclosure) is satisfied when a standby time Ta (corresponding to an example of the second time in the present disclosure) has elapsed from a determination start timing (corresponding to an example of the second timing in the present disclosure) after the motor drive condition is satisfied, i.e., after the control mode is switched from the standby mode to the brake mode. The determination start timing may be set in any manner. For example, the determination start timing may be when the drive condition is satisfied, when the control mode is set to the brake mode, when the electromagnetic brake 30 is turned on, or when the first release determination process (described in detail below, see FIG. 9) starts after the transition from the standby mode to the brake mode.

[0118] Condition B (corresponding to an example of the third condition in the present disclosure) is met when the motor rotation speed remains equal to or less than the second rotation speed threshold R2 for a rotation speed determination time Tb (corresponding to an example of the first time in the present disclosure) from the measurement start timing (corresponding to an example of the first timing in the present disclosure) after condition A is met. The second rotation speed threshold R2 may be set in any manner. For example, the second rotation speed threshold R2 may be zero. The measurement start timing may be set in any manner. For example, the measurement start timing may be the first time condition A is met after transitioning from standby mode to brake mode.

[0119] Condition C (corresponding to an example of the fifth condition in the present disclosure) is met when the motor 25 is rotating in the direction opposite to the set rotation direction. Condition C can be met, for example, when the electric cart 1 is stopped on an uphill slope and the drive lever 14a is operated, causing the electric cart 1 to descend due to gravity.

[0120] If the motor drive conditions are no longer met during the drive mode, for example, because the drive lever 14a is released, the control circuit 51 switches the control mode to the standby mode. In this case, the control circuit 51 gradually increases the braking force of the two-phase short-circuit brake to reduce the speed of the electric cart 1. Then, when the motor 25 stops rotating, the control circuit 51 applies the electromagnetic brake 30 and the three-phase short-circuit brake.

[0121] (4) Main control process The main control process executed by the control circuit 51 (more specifically, the CPU 51a) to realize the above-described control of the motor 25 will be described with reference to Fig. 6. When the control circuit 51 (more specifically, the CPU 51a) is started up, it executes the main process shown in Fig. 8.

[0122] When the control circuit 51 starts the main processing, it determines in S110 whether or not the control period has elapsed. The control period may be set in advance, for example. If the control period has not elapsed (S110: NO), the control circuit 51 repeats the processing of S110 until the control period has elapsed. If the control period has elapsed (S110: YES), the control circuit 51 executes switch information acquisition processing in S120.

[0123] In the switch information acquisition process, the control circuit 51 acquires the aforementioned signals input to the control circuit 51 from various switches, such as the trigger switch 102, the mechanical brake switch 60, the main power switch 101, the speed changeover switch 105, the direction changeover switch 104, and the battery changeover switch 81. In addition, in the switch information acquisition process, the control circuit 51 acquires a pull amount detection signal input from the pull amount detection unit 103.

[0124] When the switch information acquisition process is completed, the control circuit 51 executes a power supply control process in S130. In the power supply control process, the control circuit 51 sets the power supply control signal to on or off based on the main power switch signal acquired in S120. Specifically, if the main power switch 101 is turned on while the power supply control signal is set to off, the control circuit 51 sets the power supply control signal to on. If the main power switch 101 is turned on while the power supply control signal is set to on, the control circuit 51 sets the power supply control signal to off.

[0125] When the power supply control process is completed, the control circuit 51 executes a battery information acquisition process in S140. In the battery information acquisition process, the control circuit 51 acquires a first voltage signal input from the first voltage detection unit 85 and a second voltage signal input from the second voltage detection unit 86. In addition, in the battery information acquisition process, the control circuit 51 acquires first communication information input from the first communication unit 87 and second communication information input from the second communication unit 88.

[0126] When the battery information acquisition process is completed, the control circuit 51 executes a control mode setting process in S150. The details of the control mode setting process are as shown in FIG. 7. When the control circuit 51 starts the control mode setting process, it determines the motor drive conditions in S201. The control circuit 51 also detects the motor rotation speed. In subsequent processes during the current control cycle, the determination result of the motor drive conditions and the motor rotation speed obtained in S201 are used.

[0127] In S202, the control circuit 51 determines whether the motor drive conditions are met. If the motor drive conditions are met (S202: YES), the control circuit 51 starts measuring the drive time and resets the stop time in S203. If drive time measurement has already started, the measurement continues. If the motor drive conditions are not met (S202: NO), the control circuit 51 resets the drive time and starts measuring the stop time in S204. If stop time measurement has already started, the measurement continues.

[0128] After completing the processing of S203 or S204, the control circuit 51 determines the current control mode in S205. In the initial state immediately after the main control processing is started, the control mode is set to, for example, the initial mode. If the current control mode is the initial mode, the control circuit 51 initializes various variables used to control the motor 25 in S211. The various variables include various flags (described later), whether or not the brake can be released (described later), the speed mode, the set rotation direction, and the brake command rotation speed. In S211, the control circuit 51, for example, clears various flags, disables brake release, sets the speed mode to the low-speed mode, sets the set rotation direction to the first direction (the direction in which the electric transporter 1 moves forward), and sets the brake command rotation speed to 0.

[0129] In S212, the control circuit 51 sets the control mode to the standby mode. In S213, the control circuit 51 calculates the duration of the currently set control mode. After the process of S213, the process proceeds to S160 (see FIG. 6).

[0130] If the current control mode is the standby mode in S205, the control circuit 51 executes the process of S221. In S221, the control circuit 51 determines whether the motor drive conditions are met, as in S202. If the motor drive conditions are met (S221: YES), the control circuit 51 sets the control mode to the first brake mode in S222. In other words, if the motor drive conditions are met, the control circuit 51 does not immediately transition to the drive mode, but transitions to the first brake mode in order to maintain the state in which the short-circuit brake is applied. After completing the process of S222, the control circuit 51 executes the process of S213. If the motor drive conditions are not met in S221 (S221: NO), the control circuit 51 transitions to the process of S213.

[0131] If the current control mode is the first brake mode in S205, the control circuit 51 executes the process of S301 shown in FIG. 8. In S301, the control circuit 51 determines whether the motor drive condition is met, as in S202. If the motor drive condition is not met (S301: NO), the control circuit 51 sets the control mode to the standby mode in S307. After completing the process of S307, the control circuit 51 proceeds to the process of S213 (see FIG. 7).

[0132] If the motor drive condition is met in S301 (S301: YES), the control circuit 51 executes a first release determination process in S302. The first release determination process is a process for determining whether or not the short circuit brake may be released. Details of the first release determination process are as shown in FIG. 9.

[0133] When the control circuit 51 transitions to the first release determination process, it determines in S311 whether or not the first release determination process has just started, that is, whether or not the first first release determination process is being executed after transitioning from standby mode to first brake mode.

[0134] If the first release determination process has just started (S311: YES), the control circuit 51 determines in S312 whether the motor rotation speed is equal to or greater than the first rotation speed threshold R1 and the currently calculated brake control amount is less than the control amount threshold M1. In other words, the control circuit 51 determines whether the first condition described above is met.

[0135] If the motor rotation speed is equal to or greater than the first rotation speed threshold R1 and the currently calculated brake control amount is less than the control amount threshold M1 (i.e., if the first condition is met) (S312: YES), the control circuit 51 executes brake release processing in S313. Specifically, the control circuit 51 permits brake release. Note that brake release here means releasing the short-circuit brake. After completing the processing of S313, the control circuit 51 proceeds to the processing of S303 (see FIG. 8).

[0136] In S312, if the motor rotation speed is less than the first rotation speed threshold R1 and / or the currently calculated brake control amount is greater than or equal to the control amount threshold M1 (S312: NO), the control circuit 51 proceeds to processing of S303 without allowing brake release.

[0137] If it is not immediately after the start of the first release determination process in S311, that is, if the second or subsequent first release determination process is being executed after transition from the standby mode to the first brake mode (S311: NO), the control circuit 51 proceeds to the process of S314.

[0138] In S314, the control circuit 51 determines whether the standby time Ta has elapsed since the start of the determination. That is, the control circuit 51 determines whether the condition A is satisfied. One of the purposes of the process of S314 is to avoid the processes of S315 and S316 from being executed during a transition period immediately after the transition from the standby mode to the first brake mode, for example.

[0139] If the waiting time Ta has not elapsed since the determination start timing (i.e., if the condition A is not met) (S314: NO), the control circuit 51 ends this first release determination process and proceeds to the process of S303 (see FIG. 8).

[0140] If the standby time Ta has elapsed since the determination start timing (i.e., if condition A is met) (S314: YES), the control circuit 51 executes the process of S315. In S315, the control circuit 51 determines whether the state in which the motor rotation speed is equal to or less than the second rotation speed threshold continues for the rotation speed determination time Tb. In other words, the control circuit 51 determines whether the above-mentioned condition B is met.

[0141] More specifically, in S315, the control circuit 51 determines whether the motor rotation speed has been equal to or less than the second rotation speed threshold value R2 for the rotation speed determination time Tb from the measurement start timing. The measurement start timing may be, for example, the first time it is determined in S314 that condition A is satisfied after the mode has shifted from the standby mode to the brake mode.

[0142] If the motor rotation speed remains below the second rotation speed threshold for the rotation speed determination time Tb (i.e., if condition B is met) (S315: YES), the control circuit 51 executes the brake release process in S317 as in S313. After completing the brake release process, the control circuit 51 proceeds to the process of S303 (see FIG. 8). Note that if condition B is met in S315, it may mean, for example, that the electric transporter 1 is on flat ground and the motor 25 is not rotating or is rotating at a very low speed.

[0143] If the state in which the motor rotation speed is equal to or less than the second rotation speed threshold value has not continued for the rotation speed determination time Tb (i.e., if condition B is not satisfied) (S315: NO), the control circuit 51 executes the process of S316. In S316, the control circuit 51 determines whether the current rotation direction of the motor 25 differs from the set rotation direction. In other words, the control circuit 51 determines whether the above-mentioned condition C is satisfied.

[0144] If the current rotation direction of the motor 25 matches the set rotation direction (i.e., condition C is not met) (S316: NO), the control circuit 51 proceeds to the process of S303 (see FIG. 8). If the current rotation direction of the motor 25 differs from the set rotation direction (i.e., condition C is met) (S316: YES), the control circuit 51 executes brake release processing in S317.

[0145] Returning to Figure 8, the explanation will continue. After completing the first release determination process in S302, the control circuit 51 determines in S303 whether brake release is permitted. If brake release is permitted (S303: YES), the control circuit 51 sets the control mode to the drive mode in S304. After completing the process of S304, the control circuit 51 proceeds to the process of S213 (see Figure 7).

[0146] If brake release is not permitted in S303 (S303: NO), the control circuit 51 executes the process of S305. In S305, the control circuit 51 determines whether the motor rotation speed is equal to or greater than a third rotation speed threshold R3. The third rotation speed threshold R3 is, for example, greater than the first rotation speed threshold R1. Note that the second rotation speed threshold R2 may be, for example, zero as described above, or may be greater than 0 and less than both the first and third rotation speed thresholds R1 and R3.

[0147] If the motor rotation speed is less than the third rotation speed threshold R3 in S305 (S305: NO), the control circuit 51 proceeds to the processing of S213 (see FIG. 7) while maintaining the first brake mode. If the motor rotation speed is equal to or greater than the third rotation speed threshold R3 (S305: YES), the control circuit 51 executes the processing of S306. In S306, the control circuit 51 sets the control mode to the second brake mode. After completing the processing of S306, the control circuit 51 proceeds to the processing of S213 (see FIG. 7).

[0148] If the current control mode is set to the second brake mode in S205 (see FIG. 7), the control circuit 51 executes the process of S401 shown in FIG. 10. Setting to the second brake mode may mean, for example, that the vehicle is descending a downhill slope while the braking force of the two-phase short-circuit brake is being adjusted.

[0149] In S401, the control circuit 51 determines whether the motor drive conditions are met, similarly to S202. If the motor drive conditions are not met (S401: NO), the control circuit 51 sets the control mode to the standby mode in S405. After completing the process of S405, the control circuit 51 proceeds to the process of S213 (see FIG. 7).

[0150] If the motor drive condition is met in S401 (S401: YES), the control circuit 51 executes a second release determination process in S402. The second release determination process is a process for determining whether or not the short circuit brake may be released. Details of the second release determination process are as shown in FIG. 11A.

[0151] When the control circuit 51 proceeds to the second release determination process, it determines in S411 whether the motor rotation speed is less than a fourth rotation speed threshold R4. The fourth rotation speed threshold R4 is set, for example, according to the currently set target rotation speed. Specifically, the fourth rotation speed threshold R4 is set to a value smaller than the target rotation speed. The fourth rotation speed threshold R4 may be, for example, half the target rotation speed or a value within a predetermined range including half the target rotation speed. The target rotation speed is set in a target rotation speed setting process (see FIG. 13) described later.

[0152] If the motor rotation speed is less than the fourth rotation speed threshold R4 in S411 (S411: YES), the motor rotation speed is lower than the target rotation speed, and so the control circuit 51 executes the brake release process in S413, similar to S313. After completing the brake release process, the control circuit 51 proceeds to the process of S403 (see FIG. 10).

[0153] If the motor rotation speed is equal to or greater than the fourth rotation speed threshold R4 in S411 (S411: NO), the control circuit 51 determines in S412 whether the currently set brake control amount is less than the control amount threshold M1. If the brake control amount is less than the control amount threshold M1 (S412: YES), this indicates that a large braking force is not required, and the control circuit 51 executes brake release processing in S413. If the brake control amount is equal to or greater than the control amount threshold M1 (S412: NO), the control circuit 51 proceeds to the processing of S403 (see FIG. 10).

[0154] In S403, the control circuit 51 determines whether brake release is permitted. If brake release is permitted (S403: YES), the control circuit 51 sets the control mode to the drive mode in S404. After completing the processing of S404, the control circuit 51 proceeds to the processing of S213 (see FIG. 7).

[0155] If brake release is not permitted in S403 (S403: NO), the control circuit 51 maintains the second brake mode and proceeds to the process of S213 (see FIG. 7). If the current control mode is set to the drive mode in S205 (see FIG. 7), the control circuit 51 executes the process of S501 shown in FIG. 10. The control circuit 51, which has been set to the drive mode, releases the short-circuit brake (i.e., sets the brake control amount to 0), and supplies three-phase drive power to the motor 25 to drive the motor 25.

[0156] In S501, the control circuit 51 determines whether the motor drive conditions are met. If the motor drive conditions are not met (S501: NO), the control circuit 51 sets the control mode to the standby mode in S505. After completing the process of S505, the control circuit 51 proceeds to the process of S213 (see FIG. 7).

[0157] If the motor drive condition is met in S501 (S501: YES), the control circuit 51 executes a brake start determination process in S502. The brake start determination process is a process for determining whether or not a situation has arisen in which short-circuit braking should be applied. Details of the brake start determination process are as shown in FIG. 11B.

[0158] When the control circuit 51 proceeds to the braking start determination process, it determines in S511 whether the motor rotation speed is greater than a fifth rotation speed threshold R5. The fifth rotation speed threshold R5 is set, for example, according to the currently set target rotation speed. Specifically, the fifth rotation speed threshold R5 is set to a value greater than the target rotation speed. For example, the fifth rotation speed threshold R5 may be a value that is higher than the target rotation speed by a predetermined number of rotations.

[0159] If the motor rotation speed is equal to or less than the fifth rotation speed threshold R5 in S511 (S511: NO), the control circuit 51 proceeds to the process of S503 (see FIG. 10). If the motor rotation speed is greater than the fifth rotation speed threshold R5 in S511 (S511: YES), the control circuit 51 determines whether the currently detected motor current value is less than the current threshold in S512. If the motor current value is equal to or greater than the current threshold (S512: NO), the control circuit 51 proceeds to the process of S503 (see FIG. 10).

[0160] If the motor current value is less than the current threshold (S512: YES), it may be that the motor 25 is rotating at a relatively high speed under a light load. More specifically, it may be that the electric transporter 1 has been traveling on flat ground and is now approaching a downhill slope, causing the speed to increase due to gravity.

[0161] Therefore, if the motor current value is less than the current threshold value (S512: YES), the control circuit 51 sets a brake start request flag in S513 to apply short-circuit braking. After completing the process of S513, the control circuit 51 proceeds to the process of S503 (see FIG. 10). Note that the determination process of S512 may be omitted.

[0162] In S503, the control circuit 51 determines whether or not the braking start request flag is set. If the braking start request flag is set (S503: YES), the control circuit 51 sets the control mode to the second braking mode in S504. In S504, the control circuit 51 also clears the braking start request flag. After completing the processing of S504, the control circuit 51 proceeds to the processing of S213 (see FIG. 7).

[0163] After completing the control mode setting process in FIG. 7, the control circuit 51 proceeds to the process of S160 (see FIG. 6). In S160, the control circuit 51 executes an electromagnetic brake control process. The details of the electromagnetic brake control process are as shown in FIG.

[0164] When the control circuit 51 transitions to the electromagnetic brake control processing, it determines the current control mode in S601. If the current control mode is the initial mode, the control circuit 51 executes initialization related to the electromagnetic brake processing in S602. Then, in S603, the control circuit 51 turns on the electromagnetic brake 30 to generate a braking force by the electromagnetic brake 30. After turning on the electromagnetic brake 30 in S603, the control circuit 51 transitions to the processing of S170 (see FIG. 6).

[0165] If the current control mode is the standby mode in S601, the control circuit 51 determines the motor stop state in S604. That is, it determines whether the motor 25 is stopped (not rotating). If the motor 25 is not stopped (S604: NO), the control circuit 51 proceeds to the process of S170 (see FIG. 6). If the motor 25 is stopped (S604: YES), the control circuit 51 turns on the electromagnetic brake 30 in S605, as in S603. After turning on the electromagnetic brake 30 in S605, the control circuit 51 proceeds to the process of S170 (see FIG. 6). Note that "the motor 25 is stopped" in S604 may or may not be limited to the motor 25 being completely stopped (i.e., the rotation speed is 0). For example, a state in which the motor 25 is rotating at or below a predetermined threshold (considered an example of the third rotation speed threshold in this disclosure) may also be included in the "motor 25 is stopped" state. The predetermined threshold may be, for example, a value close to 0 or may be 0 itself.

[0166] If the current control mode is any one of the first brake mode, the second brake mode, or the drive mode in S601, the control circuit 51 turns off the electromagnetic brake 30 in S606 to release the braking by the electromagnetic brake 30. After turning off the electromagnetic brake 30 in S606, the control circuit 51 proceeds to the processing of S170 (see FIG. 6).

[0167] In S170, the control circuit 51 executes a motor control process, the details of which are shown in FIG. When the control circuit 51 transitions to the motor control process, it executes a target rotation speed setting process in S171. Specifically, the control circuit 51 executes a speed mode setting process and a set rotation direction setting process. The speed mode setting process includes switching the speed mode or maintaining the current state based on the speed selector switch signal acquired in S120. The set rotation direction setting process includes switching the set rotation direction or maintaining the current state based on the direction selector switch signal acquired in S120. In S171, the control circuit 51 further sets a target rotation speed and a target duty ratio based on the speed mode set in the speed mode setting process, the set rotation direction set in the set rotation direction setting process, and the pull amount of the drive lever 14a. The target duty ratio is a target value for the duty ratio of the motor control signal.

[0168] After completing the process of S171, the control circuit 51 executes the motor output control process in S172. The details of the motor output control process are as shown in FIG. 14. When the control circuit 51 moves to the motor output control process, in S611 it determines the current control mode. If the current control mode is the initial mode, the control circuit 51 executes initialization of the motor drive process in S612. The motor drive process is executed in S651. As will be described later, the motor drive process is a process for controlling the motor 25 so that the electric cart 1 travels at a speed corresponding to the amount of pulling of the drive lever 14a. In S612, various variables, flags, counters, etc. calculated in the motor drive process are initialized. As a result, the output of the motor control signal is stopped, and three-phase drive power is not supplied from the drive circuit 52 to the motor 25.

[0169] In S613, the control circuit 51 initializes the brake process. Specifically, the control circuit 51 sets the brake control amount to 0 and the brake command rotation speed to 0. As a result, both the short-circuit brake and the electromagnetic brake 30 are turned off.

[0170] In S611, when the current control mode is the standby mode, the control circuit 51, in S621, executes initialization of the motor drive process in the same manner as in S612. After completing the process of S621, the control circuit 51, in S622, executes the standby brake process. The details of the standby brake process are as shown in FIG. 15.

[0171] When the control circuit 51 shifts to the standby brake process, in S701, it determines whether it is immediately after the execution of the standby brake process, that is, whether it is during the execution of the first standby brake process after switching from a mode other than the standby mode to the standby mode. If it is immediately after the execution of the standby brake process (S701: YES), the control circuit 51 executes the process of S702.

[0172] In S702, the control circuit 51 determines whether the currently set brake command rotational speed is 0. Note that the initial value of the brake command rotational speed is 0 as described above. The brake command rotational speed is the target value of the rotational speed of the motor 25 to be reduced by the two-phase short-circuit brake in the two-phase short-circuit brake. As will be described later, the brake control amount is calculated based on the brake command rotational speed and the actual motor rotational speed so that the motor rotational speed matches (or approaches) the brake command rotational speed.

[0173] If the brake command rotational speed is not 0 (S702: NO), the control circuit 51 shifts to the process of S704. If the brake command rotational speed is set to 0 (S702: YES), the control circuit 51 executes the process of S703. In S703, the control circuit 51 initially sets the brake command rotational speed based on the current motor rotational speed. The initial setting of the brake command rotational speed in S703 may be performed by any method. For example, a rotational speed lower by a first specified rotational speed than the current motor rotational speed may be set as the brake command rotational speed. Also, for example, P% (e.g., 50 < P < 100) of the current motor rotational speed may be set as the brake command rotational speed.

[0174] In S704, the control circuit 51 clears the three-phase brake flag. In this embodiment, clearing the three-phase brake flag means that the three-phase short circuit brake is released, that is, no braking force is generated by the three-phase short circuit brake. After completing the processing of S704 (i.e., completing the motor control processing of S170), the control circuit 51 proceeds to S110 (see FIG. 6).

[0175] If it is not immediately after execution of standby brake processing in S701 (S701: NO), the control circuit 51 determines in S706 whether the motor 25 is stopped. If the motor 25 is rotating (S706: NO), the control circuit 51 proceeds to processing in S708. If the motor 25 is stopped (S706: YES), the control circuit 51 sets a three-phase brake flag in S707. Note that the three-phase short-circuit brake is not yet activated at this point.

[0176] In S708, the control circuit 51 determines whether the three-phase brake flag is set. If the three-phase brake flag is set (S708: YES), the control circuit 51 proceeds to processing of S709. In S709, the control circuit 51 sets the brake command rotation speed to 0. Next, in S710, the control circuit 51 sets the brake control amount to 100%. Next, in S711, the control circuit 51 outputs the three-phase short-circuit brake. That is, the three-phase short-circuit brake is activated to generate a braking force by the three-phase short-circuit brake. After completing the processing of S711, the control circuit 51 proceeds to S110 (see FIG. 6). Note that although the brake control amount of the two-phase short-circuit brake is set to 100% in S710, the first to third terminals 25U to 25W are short-circuited with each other in S711, so the two-phase short-circuit brake is not actually performed.

[0177] If the three-phase brake flag is not set in S708 (S708: NO), the control circuit 51 proceeds to the processing of S712. The transition from S708 to S712 means that the motor 25 is rotating by inertia or by receiving an external force.

[0178] The processes of S712 to S714 are for gradually reducing the rotational speed of the rotating motor 25 (in other words, gradually increasing the braking force of the two-phase short-circuit brake) and finally stopping the motor 25.

[0179] In S712, the control circuit 51 executes the arithmetic processing of the brake command rotational speed. Specifically, the control circuit 51 does not immediately set the brake command rotational speed to the final target of 0, but reduces it (for example, slightly reduces it) from the currently set value. The control circuit 51 may calculate the amount of reduction in S712 in any way. For example, a value obtained by subtracting the second specified rotational speed from the current brake command rotational speed may be set as the new brake command rotational speed. Also, for example, a value obtained by subtracting Q% (for example, 0 < Q < 30) of the current brake command rotational speed from the current brake command rotational speed may be set as the new brake command rotational speed.

[0180] In S713, the control circuit 51 calculates the brake control amount based on the difference between the brake command rotational speed calculated in S712 and the current motor rotational speed. Specifically, in order to reduce the motor rotational speed to the brake command rotational speed, the brake control amount is calculated such that the larger the motor rotational speed is than the brake command rotational speed, the larger the brake control amount (that is, the larger the braking force).

[0181] In S714, the control circuit 51 applies the two-phase short-circuit brake according to the brake control amount calculated in S713. That is, the control circuit 51 controls the drive circuit 52 to adjust the two short-circuited terminals and the short-circuit period so that a braking force corresponding to the brake control amount is generated.

[0182] By repeatedly executing the processes of S712 to S714 for each control cycle, the brake command rotational speed gradually decreases, and as a result, the motor rotational speed gradually decreases. The control circuit 51 that has completed the process of S714 proceeds to S110 (see FIG. 6).

[0183] Returning to Fig. 14, the description will continue. If the current control mode is the first brake mode in S611, the control circuit 51 executes initialization of the motor drive process in S631, similar to S612.

[0184] After completing the process of S631, the control circuit 51 executes a first brake process in S632. The first brake process is a process for gradually weakening the braking force of the short circuit brake without immediately releasing the short circuit brake when rotating the stopped motor 25. More specifically, the first brake process is a process for switching the short circuit brake from a three-phase short circuit brake to a two-phase short circuit brake and gradually weakening the braking force of the two-phase short circuit brake. Details of the first brake process are as shown in FIG. 16.

[0185] When the control circuit 51 transitions to the first brake process, it determines in S811 whether the first brake process has just been executed, that is, whether the first brake process is being executed for the first time since switching from a mode other than the first brake mode to the first brake mode. If the first brake process has just been executed (S811: YES), the control circuit 51 executes the process of S812. In S812, the control circuit 51 clears the three-phase brake flag.

[0186] In S813, the control circuit 51 determines whether the currently set brake command rotation speed is 0. If the brake command rotation speed is not 0 (S813: NO), the control circuit 51 proceeds to S110 (see FIG. 6). If the brake command rotation speed is set to 0 (S813: YES), the control circuit 51 executes the processing of S814. In S814, the control circuit 51 initializes the brake command rotation speed based on the current motor rotation speed.

[0187] The initial setting of the braking command rotation speed in S814 is different from that in S703. In S814, for example, a rotation speed that is higher than the current motor rotation speed by a third specified rotation speed may be set as the braking command rotation speed. Also, for example, L times (L > 1) the current motor rotation speed may be set as the braking command rotation speed. Furthermore, the control circuit 51 that has completed the process of setting S814 in S814 proceeds to S110 (see FIG. 6).

[0188] In S811, when it is not immediately after the execution of the first braking process (S811: NO), the control circuit 51 proceeds to the process of S815. In S815, the control circuit 51 adds or subtracts the braking command rotation speed. Specifically, the control circuit 51 determines the final target of the braking command rotation speed. For example, the control circuit 51 sets G% (G < 100) of the currently set target rotation speed as the final target. G% may be any value less than 100%. G% may be, for example, 50% or more (for example, 80%).

[0189] The control circuit 51 does not immediately set the braking command rotation speed to the set final target. The control circuit 51 decreases (for example, slightly decreases) or increases (for example, slightly increases) the current braking command rotation speed so that the braking command rotation speed becomes closer to the final target than the current current braking command rotation speed. That is, in S815, the control circuit 51 adjusts the braking command rotation speed so that the braking command rotation speed gradually approaches the final target as the process of this S815 is repeatedly executed for each control cycle.

[0190] The amount to be decreased or increased in S815 may be calculated in any way. For example, a value obtained by subtracting or adding a fourth specified rotation speed from the current braking command rotation speed may be set as the new braking command rotation speed. Also, for example, a value obtained by subtracting or adding J% (for example, 0 < J < 30) of the current braking command rotation speed from the current braking command rotation speed may be set as the new braking command rotation speed.

[0191] In S816, the control circuit 51 calculates a brake control amount based on the difference between the brake command rotation speed calculated in S815 and the current motor rotation speed. Specifically, in order to increase the motor rotation speed to the brake command rotation speed, the brake control amount is calculated so that the brake control amount (i.e., the braking force) becomes smaller as the motor rotation speed becomes smaller than the brake command rotation speed.

[0192] In S817, the control circuit 51 applies two-phase short-circuit braking in accordance with the brake control amount calculated in S816. For example, by repeatedly executing the processes of S815 to S817 at each control cycle, the brake command rotation speed gradually increases. If the electric cart 1 is stopped on flat ground, for example, it is expected that the electric cart 1 will not move (and therefore the motor 25 will not rotate) even if the brake control amount decreases as the brake command rotation speed increases. Therefore, in this case, it is expected that a situation will arise where the process will transition from S315 to S317 described above, and the short-circuit brake will be released, for example.

[0193] For example, if the electric vehicle 1 is stopped on a downhill slope, when the motor drive conditions are met and the electromagnetic brake 30 is released, it is expected that the electric vehicle 1 will start to move little by little due to gravity (i.e., the motor 25 will start to rotate little by little). However, because the two-phase short circuit brake is applied, the motor rotation speed will not increase suddenly. Then, as the brake command rotation speed increases, the brake control amount decreases, and once the speed of the electric vehicle 1 increases to a certain extent, it is expected that the second brake process (see FIG. 17), which will be described later, will be executed and the two-phase short circuit brake will continue to be maintained.

[0194] Returning to Figure 14, the description will continue. If the current control mode is the second brake mode in S611, the control circuit 51 executes initialization of the motor drive process in S641, similar to S612.

[0195] After completing the process of S641, the control circuit 51 executes a second brake process in S642. The second brake process is intended to suppress the acceleration of the motor 25 by two-phase short-circuit braking in a situation where, for example, the vehicle is descending a downhill slope due to gravity.

[0196] When the control circuit 51 transitions to the second brake process, it determines in S901 whether the second brake process has just been executed, that is, whether the first second brake process is being executed after switching from a mode other than the second brake mode to the second brake mode. If the second brake process has just been executed (S901: YES), the control circuit 51 executes the process of S902. In S902, the control circuit 51 clears the three-phase brake flag.

[0197] In S903, the control circuit 51 determines whether the currently set brake command rotation speed is 0. If the brake command rotation speed is not 0 (S903: NO), the control circuit 51 proceeds to S905. If the brake command rotation speed is set to 0 (S903: YES), the control circuit 51 executes the processing of S904. In S904, the control circuit 51 initializes the brake command rotation speed based on the current motor rotation speed, similar to S814.

[0198] In S905, the control circuit 51 determines whether the brake control amount has been initialized. The brake control amount is initialized (for example, set to 0) in S613 described above and S652 described below. If the brake control amount has not been initialized (S905: NO), the control circuit 51 proceeds to S110 (see FIG. 6). If the brake control amount has been initialized (S905: YES), the control circuit 51 executes the processing of S906. In S906, the control circuit 51 sets an initial value of the brake control amount based on the current motor rotation speed. For example, the initial value of the brake control amount is set so that the brake control amount increases as the motor rotation speed increases. After completing the processing of S906, the control circuit 51 proceeds to S110 (see FIG. 6).

[0199] If it is not immediately after the execution of the second brake process in S901 (S901: NO), the control circuit 51 executes the processes of S907 to S909. In this embodiment, the processes of S907 to S909 are the same as, for example, the processes of S815 to S817 shown in Fig. 16. Therefore, a description of S907 to S909 will be omitted.

[0200] Returning to FIG. 14, the explanation will be continued. If the current control mode is the drive mode in S611, the control circuit 51 executes motor drive processing in S651. The motor drive processing is processing for controlling the drive of the motor 25 based on the target rotation speed and target duty ratio set in S171. In this embodiment, the control circuit 51, for example, first performs constant duty control and then switches to constant rotation control. In constant duty control, the motor 25 is controlled based on the target duty ratio. In constant rotation control, the motor 25 is controlled based on the target rotation speed.

[0201] Here, a supplementary explanation will be given of the method for setting the target rotation speed and the target duty ratio in S171. In S171, the control circuit 51 sets the target duty according to the amount of pulling of the drive lever 14a. For example, when the amount of pulling is equal to or less than the pulling amount threshold (hereinafter referred to as small operation), the control circuit 51 sets the target duty ratio to a first target duty ratio. For example, when the amount of pulling is greater than the pulling amount threshold (hereinafter referred to as large operation), the control circuit 51 sets the target duty ratio to a second target duty ratio. The second target duty ratio is greater than the first target duty ratio.

[0202] In S171, the control circuit 51 further sets the initial duty ratio and the initial output period according to the pull amount. Specifically, during a small operation, the control circuit 51 sets the initial duty ratio to a first initial duty ratio. The first initial duty ratio is smaller than the first target duty ratio. For example, during a large operation, the control circuit 51 sets the initial duty ratio to a second initial duty ratio. The second initial duty ratio is smaller than the second target duty ratio and larger than the first initial duty ratio. Furthermore, during a small operation, the control circuit 51 sets the initial output period to the first initial output period. For example, during a large operation, the control circuit 51 sets the initial output period to the second initial output period. The second initial output period is shorter than the first initial output period.

[0203] At the start of the motor drive process, the control circuit 51 sets the duty ratio of the motor control signal to an initial duty ratio and drives the motor 25. For example, during a small operation, the control circuit 51 outputs a motor control signal with a first initial duty ratio. The control circuit 51 outputs the motor control signal with the initial duty ratio continuously for an initial output period. For example, during a large operation, the control circuit 51 outputs the motor control signal with a second initial duty ratio continuously for a second initial output period.

[0204] After the initial output period has elapsed, the control circuit 51 gradually increases the duty ratio of the motor control signal from the initial duty ratio toward the target duty ratio. The manner in which the duty ratio is increased varies depending on the amount of pull. For example, during small operation, the duty ratio is increased to the target duty ratio over a longer period than during large operation. The increasing trend of the duty ratio during large operation may be, for example, linear. The increasing trend of the duty ratio during small operation may be, for example, exponential.

[0205] The control circuit 51, which is currently executing constant duty control, switches the control method to constant rotation control when a control switching condition is met. The control switching condition is met, for example, when the following first to third states continue simultaneously for a first specified time. The first state corresponds to a state in which the duty ratio of the motor control signal has reached K% (K<100) of the target duty ratio. The second state corresponds to a state in which the motor rotation speed is greater than a sixth rotation speed threshold R6. The third state corresponds to a state in which a second specified time has elapsed since the start of output of the motor control signal with the initial duty ratio.

[0206] After switching the control method to constant speed control, the control circuit 51 performs PI (proportional-integral) control of the duty ratio of the motor control signal so that the motor speed matches the target speed. The control gain used in PI control is larger during large operation than during small operation.

[0207] The above-described control of the motor 25 during the drive mode is realized by repeatedly executing the motor drive process of S651 for each control period. During the drive mode, steps S651 to S652 are repeatedly executed for each control period. In S652, the brake process is initialized, as in S613. Therefore, during the drive mode, both the electromagnetic brake 30 and the short-circuit brake are released.

[0208] (5) Correspondence between the embodiments and the present disclosure The drive lever 14a corresponds to an example of a manual operation receiving portion in the present disclosure. The brake lever 13b and the mechanical brake 24 correspond to an example of a mechanical brake in the present disclosure.

[0209] Execution of S304 in response to execution of S313, which in turn executes S652, corresponds to an example of a third process in the present disclosure. Execution of S304 in response to execution of S317, which in turn executes S652, corresponds to an example of a fourth process in the present disclosure. The process of S corresponds to an example of a process in the present disclosure. The process of S605 corresponds to an example of an electromagnetic brake process in the present disclosure. The process of S606 corresponds to an example of a brake release process in the present disclosure. The processes of S709 to S713 correspond to an example of a first process in the present disclosure. The processes of S816 to S817 correspond to an example of a second process in the present disclosure.

[0210] [Other embodiments] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0211] (1) The short-circuit brake that is activated when the motor 25 is stopped may be a two-phase short-circuit brake, or may be selectively switched between a three-phase short-circuit brake and a two-phase short-circuit brake. The three-phase short-circuit brake may be temporarily activated when the motor 25 is rotating.

[0212] (2) The electric vehicle 1 may have one, two, or three wheels, or may have five or more wheels. In an electric vehicle with multiple wheels, any number of drive wheels may be driven by a motor.

[0213] (3) The electric transporter 1 may be capable of mounting only one battery pack, or may be capable of mounting three or more battery packs. (4) Multiple functions of one component in the above embodiments may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0214] 1...electric transport vehicle, 2...main body, 3...cargo bed, 8, 9...front wheels, 10, 11...rear wheels, 12a...right grip, 13a...left grip, 13b...brake lever, 14a...drive lever, 15...battery box, 24...mechanical brake, 25...motor, 25U to 25W...first to third terminals, 25a to 25c...first to third windings, 27...motor rotor, 28...motor shaft, 30...electromagnetic brake, 50...first controller, 51 ...Control circuit, 51a...CPU, 51b...memory, 52...drive circuit, 61...first battery pack, 62...second battery pack, 64...rotation sensor, 70...second controller, 86...second voltage detection unit, 87...first communication unit, 87...second voltage detection unit, 88...second communication unit, 89...first communication unit, 90...second communication unit, 101...main power switch, 102...trigger switch, 103...pull amount detection unit, 104...direction change switch.

Claims

1. An electric transport vehicle, a handle configured to be held by a user standing on the ground on which the electric transporter travels and using the electric transporter; a battery housing configured to house a battery; a motor configured to rotate by power from the battery housed in the battery housing, the motor having a plurality of windings and a plurality of terminals connected to the plurality of windings; a wheel configured to be driven by the motor; a control circuit configured to control the driving of the motor; a manual operation receiving unit configured to instruct the control circuit to drive the motor in response to receiving a first manual operation by the user; Equipped with The control circuit a first process for generating a braking force on the motor by short-circuit braking that short-circuits two or more of the plurality of terminals in response to the drive condition of the motor not being satisfied; a second process for gradually reducing the braking force of the short-circuit brake in response to a state change occurring from a state in which the drive condition is not satisfied to a state in which the drive condition is satisfied; is configured to run the drive condition is satisfied in response to the manual operation receiving unit receiving the first manual operation; Electric transport vehicle.

2. The electric transport vehicle according to claim 1, The control circuit further comprises: a third process of releasing the short-circuit brake in response to the first condition being satisfied when the state change occurs; is configured to run the first condition is met without the need for an input operation by the user to the electric transport vehicle; Electric transport vehicle.

3. The electric transport vehicle according to claim 2, The electric transporter, wherein the first condition includes that the number of rotations per unit time of the motor is equal to or greater than a first threshold number of rotations.

4. The electric transport vehicle according to claim 2, the first process includes gradually increasing the braking force of the short-circuit brake in response to a change from a state in which the drive condition is satisfied to a state in which the drive condition is not satisfied during rotation of the motor, the first condition includes that the number of rotations per unit time of the motor is equal to or greater than a first rotation number threshold, and the braking force of the currently generated short-circuit brake is smaller than a braking force threshold. Electric transport vehicle.

5. The electric transport vehicle according to any one of claims 1 to 4, The control circuit further comprises: a fourth process of releasing the short circuit brake in response to a second condition being satisfied after the state change has occurred; a motorized transport vehicle configured to:

6. An electric transport vehicle as described in claim 5, the second condition is met without the need for an input operation by the user to the electric transporter, the fourth process further includes supplying power to the motor to drive the motor. Electric transport vehicle.

7. The electric transport vehicle according to claim 5 or 6, the second condition is satisfied in response to the third condition being satisfied, the third condition is satisfied when the number of rotations per unit time of the motor is maintained equal to or less than a second rotation number threshold for a first period of time from a first timing after the state change occurs. Electric transport vehicle.

8. An electric transport vehicle as described in claim 7, The electric transport vehicle, wherein the second rotation speed threshold is zero.

9. An electric transport vehicle according to claim 7 or claim 8, the second condition is satisfied in response to the third condition being satisfied after the fourth condition is satisfied, the fourth condition is satisfied when a second time period has elapsed since a second timing after the state change has occurred, the first timing occurs after the fourth condition is satisfied; Electric transport vehicle.

10. The electric transport vehicle according to any one of claims 5 to 9, The control circuit further comprises: a direction setting process for setting a rotation direction of the motor; a motor control process for controlling the motor so that the motor rotates in a set rotation direction, which is the rotation direction set by the direction setting process; is configured to run the second condition is satisfied in response to the fifth condition being satisfied, the fifth condition is satisfied when the motor is rotating in a direction opposite to the set rotation direction; Electric transport vehicle.

11. An electric transport vehicle as described in claim 10, the second condition is satisfied in response to the fifth condition being satisfied after the fourth condition is satisfied, the fourth condition is satisfied when a second time period has elapsed since a second timing after the occurrence of the state change. Electric transport vehicle.

12. An electric transport vehicle according to any one of claims 1 to 11, moreover, a mechanical brake configured to receive a second manual operation by the user and directly brake rotation of the wheel in accordance with an amount of the second manual operation; Equipped with The drive condition is satisfied when the manual operation receiving unit receives the first manual operation and when braking by the mechanical brake is released. Electric transport vehicle.

13. The electric transport vehicle according to any one of claims 1 to 12, an electromagnetic brake including an electromagnet configured to brake the motor or release the brake of the motor by a magnetic force generated by the electromagnet; The control circuit further comprises: an electromagnetic brake process for braking the motor by the electromagnetic brake when the drive condition is not satisfied; 1. A motorized transport vehicle configured to:

14. 14. The electric transporter according to claim 13, the electromagnetic brake processing includes braking the motor by the electromagnetic brake when the drive condition is not satisfied and the rotation speed of the motor per unit time is equal to or less than a third rotation speed threshold. Electric transport vehicle.

15. The electric transport vehicle according to claim 13 or 14, The control circuit further comprises: a braking release process for releasing the braking of the motor by the electromagnetic brake in response to the occurrence of the state change; 1. A motorized transport vehicle configured to:

16. The electric transport vehicle according to any one of claims 1 to 15, the plurality of terminals includes three terminals; the motor is configured to rotate when three-phase power is supplied to the three terminals; The short-circuit brake for the motor when stopped includes a three-phase short-circuit brake that generates a braking force on the motor by short-circuiting the three terminals together. Electric transport vehicle.

17. The electric transport vehicle according to any one of claims 1 to 16, the plurality of terminals includes three terminals; the motor is configured to rotate when three-phase power is supplied to the three terminals; The short-circuit brake applied to the rotating motor includes continuously or intermittently applying a two-phase short-circuit brake that generates a braking force on the motor by short-circuiting two of the three terminals together, intermittently applying a three-phase short-circuit brake that generates a braking force on the motor by short-circuiting the three terminals together, and / or selectively switching between applying the two-phase short-circuit brake and the three-phase short-circuit brake. Electric transport vehicle.

18. An electric transport vehicle according to any one of claims 1 to 17, the plurality of terminals includes three terminals; the motor is configured to rotate when three-phase power is supplied to the three terminals; The control circuit When the motor is not rotating and the drive condition is not satisfied, a three-phase short-circuit brake is applied as the short-circuit brake in the first process; When the state change occurs from a state in which the motor is not rotating and the drive condition is not satisfied, in the second processing, (i) the short circuit brake is switched from the three-phase short circuit brake to a two-phase short circuit brake, and (ii) the braking force of the two-phase short circuit brake is gradually reduced. It is structured as follows: the three-phase short-circuit braking includes generating a braking force on the motor by short-circuiting the three terminals together; the two-phase short circuit braking includes generating a braking force on the motor by shorting two of the three terminals together; Electric transport vehicle.

19. A motor control method for use in an electric transport vehicle equipped with a motor, comprising: The electric transporter includes a handle configured to be held by a user who uses the electric transporter while standing on a ground on which the electric transporter travels, wheels configured to be driven by the motor, and a manual operation receiving unit configured to issue a command to drive the motor in response to manual operation by the user, The motor control method includes: generating a braking force in the motor by a short-circuit brake that shorts two or more of a plurality of terminals of the motor in response to the drive condition of the motor not being satisfied; gradually reducing the braking force of the short-circuit brake in response to a change from a state in which the drive condition is not satisfied to a state in which the drive condition is satisfied; Equipped with The motor control method, wherein the drive condition is satisfied in response to the manual operation being received by the manual operation receiving unit.

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