Transport vehicle

Abstract

To provide a technology capable of protecting and halting a transport vehicle which is climbing a slope in an overloaded condition, without impairing the user-friendliness of the transport vehicle.SOLUTION: A transport vehicle includes a steering wheel, a battery installation part, a motor, wheels, a detection unit, a rotation acquisition unit, and a control unit. The control unit ceases supply of electric power from a battery to the motor on the basis of a value of a current and / or voltage detected by the detection unit and rotation information acquired by the rotation acquisition unit.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] This disclosure relates to a transport vehicle powered by a motor.

Background Art

[0002] The transport vehicle described in Patent Document 1 detects the load state of the motor based on the energization state, rotational speed, and temperature of the motor, and stops the motor when the load state is overloaded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an overloaded transport vehicle climbs a slope, when descending the same slope, if the braking force is insufficient, it will continue to accelerate. Therefore, in the uphill operation by the transport vehicle in an overloaded state, it is desirable that the overload of the motor is determined and the motor is stopped. However, in the operation by the transport vehicle other than the uphill operation in the overloaded state, if the overload of the motor is determined, the motor may be stopped unnecessarily and the operation may be hindered. As a result, the usability of the transport vehicle may be impaired.

[0005] One aspect of this disclosure provides a technology that can protectively stop a transport vehicle when climbing a slope in an overloaded state without impairing the usability of the transport vehicle.

Means for Solving the Problems

[0006] A transport vehicle in one aspect of the present disclosure comprises a handle, a battery mounting section, a motor, wheels, a detection section, a rotation acquisition section, and a control section. The handle is configured to be gripped by a user. The battery mounting section is configured to mount a battery. The motor is configured to rotate using power from a battery mounted in the battery mounting section. The wheels are configured to be driven by the motor. The detection section is configured to detect the values ​​of current and / or voltage supplied from the battery to the motor. The rotation acquisition section is configured to acquire rotation information indicating the rotation state of the wheels. The control section is configured to control the drive of the motor. The control section is also configured to stop the supply of power from the battery to the motor based on the values ​​of current and / or voltage detected by the detection section and the rotation information acquired by the rotation acquisition section.

[0007] The above-mentioned transport vehicle stops supplying power from the battery to the motor based on the values ​​of the current and / or voltage supplied from the battery to the motor and the rotation state of the wheels. When the transport vehicle is overloaded and working uphill, the wheels continue to rotate while the values ​​of the current and / or voltage change. On the other hand, when the transport vehicle is working and the motor is momentarily overloaded, the wheels do not continue to rotate while the values ​​of the current and / or voltage change. Therefore, it is possible to determine whether the transport vehicle is overloaded and working uphill based on the values ​​of the current and / or voltage and the rotation state of the wheels. Consequently, the motor can be protected and stopped when the transport vehicle is overloaded and working uphill without compromising the usability of the transport vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the schematic configuration of the transport vehicle according to this embodiment. [Figure 2] This is a plan view of the left and right handles and battery box of the transport vehicle according to this embodiment, as seen from above. [Figure 3] This is a perspective view showing the appearance of the operating device provided on the right handle of the transport vehicle according to this embodiment. [Figure 4A]This diagram shows the electrical configuration of the transport vehicle according to this embodiment. [Figure 4B] This is a block diagram showing the input / output portion of the control circuit of the transport vehicle according to this embodiment. [Figure 5] This is a flowchart of the main process according to this embodiment. [Figure 6] This is a flowchart showing the switch information acquisition process according to this embodiment. [Figure 7] This flowchart shows the power control process according to this embodiment. [Figure 8] This flowchart shows the process for acquiring battery information according to this embodiment. [Figure 9] This flowchart shows the error detection process according to this embodiment. [Figure 10] This flowchart shows the overcurrent protection determination process according to this embodiment. [Figure 11] This flowchart shows the overload protection determination process according to this embodiment. [Figure 12A] This flowchart shows a part of the control mode setting process according to this embodiment. [Figure 12B] A flowchart illustrating another part of the control mode setting process according to this embodiment is provided. [Figure 12C] This flowchart shows the remaining steps in the control mode setting process according to this embodiment. [Figure 13] This flowchart shows a first example of the brake start determination process according to this embodiment. [Figure 14] This flowchart shows a second example of the brake start determination process according to this embodiment. [Figure 15] This flowchart shows the brake release determination process according to this embodiment. [Figure 16] This flowchart shows the electromagnetic brake control process according to this embodiment. [Figure 17] This flowchart shows the motor control process according to this embodiment. [Figure 18]It is a flowchart showing the setting process of the target rotation speed according to this embodiment. [Figure 19] It is a flowchart showing the motor output control process according to this embodiment. [Figure 20] It is a flowchart showing the notification control process according to this embodiment. [Figure 21] It is a flowchart showing the confirmation process of the battery capacity according to this embodiment. [Figure 22] It is a flowchart showing the display process of the battery capacity according to this embodiment. [Figure 23] It is a flowchart showing the buzzer output process according to this embodiment. [Figure 24] It is an explanatory diagram of ascending and descending slopes by the transport vehicle according to the reference example. [Figure 25] It is an explanatory diagram of ascending slopes and crossing steps by the transport vehicle according to the reference example. [Figure 26] It is a diagram showing, for the position of the wheel, (i) the second average value, (ii) the motor rotation angle, and (iii) the change in the motor rotation angle when the second average value is equal to or greater than the fourth current threshold value, when the transport vehicle according to this embodiment climbs a slope. [Figure 27] It is a diagram showing, for the position of the wheel, (i) the second average value, (ii) the motor rotation angle, (ii) the motor rotation angle, and (iii) the change in the motor rotation angle when the second average value is equal to or greater than the fourth current threshold value, when the transport vehicle according to this embodiment crosses a step.

Mode for Carrying Out the Invention

[0009] [Summary of the Embodiment] The transport vehicle in a certain embodiment includes a handle, a battery mounting portion, a motor, wheels, a detection unit, a rotation acquisition unit, and a control unit.

[0010] The detection unit may be configured to detect the value of the current. The control unit may be configured to stop supplying power to the motor in response to the fulfillment of either the first or second condition. The first condition may be fulfilled when, while the wheel is continuously rotating by a predetermined angle, the current-dependent value, based on the value of the current detected by the detection unit, remains continuously above a first threshold. The second condition is when the current-dependent value becomes above a second threshold, which is greater than the first threshold. It may be valid.

[0011] The first condition is met when the motor is continuously overloaded during uphill operation while overloaded. The second condition is met when an excessive current is flowing that immediately requires motor protection. Therefore, the motor can be stopped in either the case of uphill operation of an overloaded transport vehicle or in the case of motor overcurrent. This, in turn, allows for proper protection of both the user and the motor.

[0012] The detection unit may be configured to detect a voltage value. The control unit may be configured to stop supplying power to the motor when the voltage value detected by the detection unit falls below a first voltage threshold while the wheel is rotating continuously by a predetermined angle.

[0013] When a motor is overloaded, the current increases, leading to a greater voltage drop, and thus the voltage value decreases. During uphill work with an overloaded transport vehicle, the wheels continue to rotate while the voltage value remains low. Therefore, motor overload can be determined based on the fact that the voltage value continuously remains below the first voltage threshold.

[0014] In one embodiment, the transport vehicle may further include a notification unit. The detection unit may be configured to detect a voltage value. The notification unit may be configured to notify of a decrease in battery capacity. The control unit may be configured to cause the notification unit to notify of a decrease in capacity when the voltage value detected by the detection unit remains below a second voltage threshold while the wheels are continuously rotating by a predetermined angle.

[0015] When a transport vehicle goes over a step or other obstacle, the motor is momentarily overloaded. When the motor is momentarily overloaded, the battery voltage temporarily drops but then recovers. In such cases, if the system notifies the user of a decrease in capacity, the user may mistakenly believe that the battery needs to be charged when it does not. In one embodiment, if the transport vehicle is equipped with a notification unit, it can notify the user of a decrease in capacity when the voltage value continuously falls below a voltage threshold, allowing the user to recognize the decrease in capacity when the battery needs to be charged.

[0016] The specified angle may be greater than 360°. When a motor is momentarily overloaded, the load on the motor decreases before the wheel completes one rotation. Therefore, by setting the predetermined angle to a value greater than 360°, momentary overloads can be excluded, and the overload during uphill climbing of an overloaded transport vehicle can be accurately determined.

[0017] Embodiments of this disclosure will be described below with reference to the drawings. <1. Structure> <1-1. Overall Structure> Referring to Figure 1, the configuration of the transport vehicle 1 according to this embodiment will be described. The transport vehicle 1 comprises a front wheel 3 and two rear wheels 5. The front wheel 3 is the drive wheel, and the rear wheels 5 are the driven wheels.

[0018] The transport vehicle 1 is equipped with a motor unit 9. The motor unit 9 is equipped with a motor 400 (see Figure 4A). The motor 400 is a three-phase brushless motor. The rotating shaft of the motor 400 is physically connected to the front wheel 3 via a gear 420, and the motor 400 imparts rotational force to the front wheel 3. In other words, the front wheel 3 is driven by the motor 400.

[0019] The motor unit 9 is equipped with a position detection sensor 250 (see Figure 4A). 250 consists of three Hall sensors provided on each of the three phase windings. The position detection sensors 250 detect the rotor position of the motor 400 and output a position signal to the control circuit 120, which will be described later. The control circuit 120 detects the rotation state of the motor 400 based on the position signal. The rotation state of the motor 400 corresponds to the rotation state of the front wheel 3. In this embodiment, the position detection sensors 250 correspond to an example of the rotation acquisition unit of this disclosure.

[0020] The motor unit 9 is equipped with an electromagnetic brake 410 (see Figure 4A). The electromagnetic brake 410 comprises, for example, a brake stator, a brake plate, an armature, and a brake rotor. The brake stator contains an electromagnetic coil. The brake rotor is fixed to the rotating shaft of the motor 400. When power to the electromagnetic brake 410 is cut off, the electromagnetic brake 410 turns on, and a braking force is applied to the rotation of the brake rotor. Consequently, a braking force is applied to the rotation of the rotating shaft of the motor 400. When power is supplied to the electromagnetic brake 410, the electromagnetic brake 410 turns off, and no braking force is applied to the rotation of the brake rotor. Consequently, no braking force is applied to the rotation of the rotating shaft of the motor 400. Applying the braking force of the electromagnetic brake 410 to the motor 400 when the rotational speed of the motor 400 is high may cause the electromagnetic brake 410 to fail. Therefore, the electromagnetic brake 410 is turned on only when the rotational speed of the motor 400 is sufficiently low.

[0021] The transport vehicle 1 is equipped with a body frame 10. The body frame 10 rotatably supports the front wheels 3. The body frame 10 is constructed by bending metal rod-shaped pipe material. The body frame 10 has a symmetrical shape with respect to the rotation plane of the front wheels 3.

[0022] The vehicle frame 10 is equipped with a right handle 16R at its right end and a left handle 16L at its left end. The right handle 16R and the left handle 16L are positioned approximately horizontally to the ground. A right grip 15R is attached to the end of the right handle 16R. A left grip 15L is attached to the end of the left handle 16L. The user grasps the right grip 15R and the left grip 15L and pushes the transport vehicle 1 forward or pulls it backward. The front wheels 3 rotate not only with the power of the motor 400, but also when the user pushes or pulls the transport vehicle 1.

[0023] The transport vehicle 1 is equipped with a mechanical brake 17. The mechanical brake 17 applies braking force directly to the front wheel 3. The left handle 16L is provided with a brake lever 18 that is manually operated by the user. When the user pulls the brake lever 18, the brake pads included in the mechanical brake 17 are pressed against the front wheel 3, and braking force is applied to the front wheel 3 due to friction between the front wheel 3 and the brake pads (mechanical brake on). When the user releases the brake lever 18, the brake pads separate from the front wheel 3, and the braking force due to friction disappears (mechanical brake off). When the brake lever 18 is pulled, a mechanical brake switch (not shown) is turned on, and a mechanical brake signal indicating that it is on is output.

[0024] The transport vehicle 1 is equipped with a cargo bed frame 20. The cargo bed frame 20 secures various cargo beds for carrying loads to the vehicle body frame 10. The cargo bed frame 20 is constructed by bending metal rod-shaped pipes. The vehicle body frame 10 has a symmetrical shape with respect to the rotation plane of the front wheels 3.

[0025] The transport vehicle 1 is equipped with a rear wheel frame 33. The rear wheel frame 33 is located between the right and left frames of the vehicle body frame 10. The rear wheel frame 33 supports the cargo bed frame 20 and the two rear wheels 5. The rear wheel frame 33 rotatably supports the two rear wheels 5. Because the rear wheel frame 33 supports the two rear wheels 5 so that they can slide in the left-right direction, the user can adjust the distance between the two rear wheels 5. The two rear wheels 5 are fixed to the rear wheel frame 33 by fixing members in the adjusted distance position.

[0026] The transport vehicle 1 is equipped with two obstacle detection units 40. The two obstacle detection units 40 are provided on the right frame and left frame of the vehicle body frame 10. The obstacle detection unit 40 includes an ultrasonic sensor. The ultrasonic sensor emits ultrasonic waves toward the front of the transport vehicle 1 and receives reflected waves generated when the emitted ultrasonic waves are reflected by obstacles in front. Based on the received reflected waves, the ultrasonic sensor detects the presence or absence of an obstacle and the distance to the obstacle. The obstacle detection unit 40 may include a laser radar or an infrared sensor instead of the ultrasonic sensor.

[0027] The transport vehicle 1 is equipped with an operating device 90. The operating device 90 is located on the right handle 16R. The user operates the operating device 90 to set the driving conditions for the motor 400 and to input driving commands for the motor 400.

[0028] The transport vehicle 1 is equipped with a battery box 60. The battery box 60 is fixed to the vehicle frame 10 via a fixed frame 19 and is installed between the right handle 16R and the left handle 16L. The battery box 60 houses the first to fourth battery packs 70A to 70D. The first to fourth battery packs 70A to 70D each contain two battery sets. Each battery set contains two battery packs. One of the two battery sets is electrically connected to the motor 400 to supply power to the motor 400.

[0029] <1-2. Configuration of the Operating Device> The configuration of the operating device 90 will be described in detail with reference to Figures 2 and 3. The operating device 90 is formed in a roughly rectangular shape. The operating device 90 is equipped with a drive lever 91. The drive lever 91 corresponds to a trigger. The user operates the drive lever 91 with their right hand, which is gripping the right grip 15R. When the user pulls the drive lever 91, the trigger switch 98 becomes conductive (i.e., turns on), and when the user releases the drive lever 91, the trigger switch 98 becomes non-conductive (i.e., turns off). As shown in Figure 4A, the trigger switch 98 is provided on the positive terminal line that connects the positive terminal of the motor driver 140 to the positive terminal of the first or second battery set. The motor driver 140 is a circuit for controlling the current flowing to the motor 400. The user also commands the rotational speed of the motor 400 by the amount the drive lever 91 is pulled. The greater the pull, the higher the rotational speed commanded.

[0030] The operating device 90 includes a main power switch 92. Each time the user operates the main power switch 92, the control power is switched on and off. The main power switch 92 outputs a main power signal indicating that it is ON, depending on the operation performed by the user.

[0031] The operating device 90 includes a direction of travel selector switch 94. Each time the user operates the direction of travel selector switch 94, the set direction of travel of the transport vehicle 1 (i.e., the rotation direction of the motor 400) is switched. The set direction of travel is either forward or backward. The direction of travel selector switch 94 outputs a direction of travel signal indicating "on" depending on whether it has been operated.

[0032] The operating device 90 includes a direction of travel indicator unit 95. The direction of travel indicator unit 95 displays the direction of travel of the transport vehicle 1, which is set via the direction of travel switching switch 94. Specifically, the direction of travel indicator unit 95 includes an arrow indicator unit for forward movement and an arrow indicator unit for reverse movement, and illuminates the arrow indicator unit for the set direction of travel. Each arrow indicator unit is equipped with a light-emitting diode (LED).

[0033] The operating device 90 includes a speed selector switch 96. Each time the user operates the speed selector switch 96, the set speed mode is switched. The set speed mode is one of high speed mode, medium speed mode, or low speed mode, and switches in the order of low speed mode → medium speed mode → high speed mode → low speed mode. The speed selector switch 96 outputs a speed selector signal indicating ON depending on the operation.

[0034] The rotational speed of motor 400 is set by multiplying the upper limit speed corresponding to the speed mode by a ratio. The ratio corresponds to the actual pull amount of the drive lever 91 relative to the maximum pull amount. The upper limit speed is set to a higher value when high-speed mode is set than when low-speed mode is set.

[0035] The speed mode display unit 97 displays the speed mode set via the speed selector switch 96. The speed mode display unit 97 is equipped with LEDs and indicates the speed mode in three stages.

[0036] <1-3. Battery Box Configuration> Referring to Figure 2, the battery box 60 will be described. The battery box 60 comprises a box body 61. The box body 61 is formed as a roughly rectangular parallelepiped with an open top. The box body 61 houses the first to fourth battery packs 70A to 70D inside. Each of the first to fourth battery packs 70A to 70D comprises a battery in which multiple cells are connected in series. Each battery is a rechargeable secondary battery, such as a lithium-ion battery.

[0037] The first battery pack 70A is connected in series with the second battery pack 70B. The set of the first and second battery packs 70A and 70B connected in series constitutes the first battery set. The third battery pack 70C is connected in series with the fourth battery pack 70D. The set of the third and fourth battery packs 70C and 70D connected in series constitutes the second battery set. The lid 62 is rotatably attached to the box body 61 via a hinge and opens and closes the top surface of the box body 61.

[0038] The battery box 60 is equipped with a locking mechanism 63. The locking mechanism 63 is provided on the lid 62. The locking mechanism 63 is configured to rotate between a locked position and an unlocked position. When the locking mechanism 63 is in the locked position, the lid 62 is fixed in a closed position. When the locking mechanism 63 is in the unlocked position, the lid 62 can be opened.

[0039] The battery box 60 is equipped with a battery selector switch 71. The battery selector switch 71 is located on the cover 62. The user operates the battery selector switch 71 to select either the first battery set or the second battery set. The selected battery set is electrically connected to the motor 400. The battery selector switch 71 outputs a battery selector signal indicating the selected battery set.

[0040] The battery box 60 is equipped with first to fourth remaining capacity indicators 72A to 72D. The first to fourth remaining capacity indicators 72A to 72B are located on the lid 62. The first to fourth remaining capacity indicators 72A to 72D each display the remaining capacity of the first to fourth battery packs 70A to 70D. Each of the first to fourth remaining capacity indicators 72A to 72D includes three LEDs arranged in a row, and the remaining capacity is displayed by the number of LEDs that are lit.

[0041] The battery box 60 is equipped with a remaining capacity display switch 73. The remaining capacity display switch 73 is located on the lid 62. When the user presses the remaining capacity display switch 73, a command to display the remaining capacity is output to the control circuit 120, which will be described later. As a result, regardless of whether the first battery set or the second battery set is selected, the remaining capacity of the first to fourth battery packs 70A to 70D is displayed for a certain period of time on the first to fourth remaining capacity display units 72A to 72D.

[0042] The battery box 60 includes a collision suppression switch 74 and a collision suppression display unit 75. The collision suppression switch 74 and the collision suppression indicator unit 75 are located on the cover 62. Each time the user presses the collision suppression switch 74, the control circuit 120 switches between allowing and prohibiting the execution of suppression control. Suppression control controls the drive of the motor 400 so as to decelerate or stop the motor 400 when an obstacle is detected by the obstacle detection units 40L and 40R. The collision suppression indicator unit 75 displays whether the execution of suppression control is permitted or prohibited.

[0043] The battery box 60 includes a key insertion section 65 inside the box body 61. As shown in Figure 4A, the key insertion section 65 is located between the first and second battery sets and the trigger switch 98. When a key is inserted into the key insertion section 65 and the drive lever 91 is pulled, the positive terminal line connecting the positive terminal of the first or second battery set to the positive terminal of the motor driver 140 becomes conductive.

[0044] <1-4. Circuit Configuration> As shown in Figure 4B, the transport vehicle 1 is equipped with first to fourth voltage detection units 160A to 160D. The first to fourth voltage detection units 160A to 160D are housed in the battery box 60. Each of the first to fourth voltage detection units 160A to 160D detects the voltage values ​​of the first to fourth battery packs 70A to 70D and outputs a detection signal indicating the detected voltage value to the control circuit 120, which will be described later. The first to fourth voltage detection units 160A to 160D also constantly detect the voltage values ​​of battery packs that are not selected by the battery selector switch 71.

[0045] The transport vehicle 1 is equipped with a battery communication unit 190. The battery communication unit 190 is housed in a battery box 60. The control circuit 120 communicates with each of the first to fourth battery packs 70A to 70D via the battery communication unit 190. The control circuit 120 performs serial communication with the first to fourth battery packs 70A to 70D via the battery communication unit 190. The control circuit 120 then receives information from each of the first to fourth battery packs 70A to 70D regarding whether to permit or prohibit discharge from the battery pack to the transport vehicle 1. Alternatively, the control circuit 120 receives a discharge permit signal or a discharge prohibition signal from each of the first to fourth battery packs 70A to 70D via the battery communication unit 190.

[0046] The transport vehicle 1 is equipped with a motor temperature detection unit 170. The motor temperature detection unit 170 is housed in the motor unit 9. The motor temperature detection unit 170 detects the temperature of the motor 400 and outputs a detection signal indicating the detected temperature to the control circuit 120.

[0047] The transport vehicle 1 is equipped with a Field Effect Transistor (FET) temperature detection unit 180. The FET temperature detection unit 180 is housed in the motor unit 9. The FET temperature detection unit 180 detects the temperature of the gate circuit 130 and motor driver 140, which will be described later, and outputs a detection signal indicating the detected temperature to the control circuit 120.

[0048] As shown in Figure 4A, the transport vehicle 1 is equipped with a first controller 100. The first controller 100 is housed in the motor unit 9 and controls the drive of the motor 400. The first controller 100 includes a regulator 110. The regulator 110 is connected to the first and second battery sets via diodes. When a power control signal, which is set to ON from the control circuit 120 (described later), is input to the regulator 110, it receives power from the first and / or second battery sets and generates power to supply to various circuits provided in the first controller 100.

[0049] The first controller 100 includes a control circuit 120. The control circuit 120 includes a CPU 120a and a memory 120b. The memory 120b may have semiconductor memory such as ROM, RAM, NVRAM, or flash memory. In other words, the first controller 100 in this embodiment may be in the form of a microcomputer.

[0050] The control circuit 120 implements various functions by executing a program stored in a non-transitional physical recording medium. In this embodiment, the memory 120b corresponds to the non-transitional physical recording medium that stores the program. In this embodiment, various programs are stored in the memory 120b.

[0051] Some or all of the functions implemented by the control circuit 120 may be achieved by program execution (i.e., by software processing) or by one or more hardware components. For example, the control circuit 120 may include a logic circuit containing multiple electronic components instead of, or in addition to, a microcomputer, an application-specific integrated circuit such as an ASIC and / or ASSP, or a programmable logic device such as an FPGA capable of constructing any logic circuit.

[0052] The first controller 100 includes a motor driver 140. The motor driver 140 is a three-phase full-bridge circuit containing six FETs. The motor driver 140 is connected to the positive line and the motor 400 and controls the current flowing to the motor 400.

[0053] The first controller 100 includes a gate circuit 130. The gate circuit 130 turns on or off the six FETs of the motor driver 140 based on a control signal output from the control circuit 120.

[0054] The first controller 100 includes a regenerative prevention circuit 150. The regenerative prevention circuit 150 is located in the positive terminal line between the trigger switch 98 and the motor driver 140. The regenerative prevention circuit 150 includes two reverse current prevention elements to prevent regenerative current from flowing from the motor driver 140 to the positive terminal of the first or second battery set.

[0055] The first controller 100 includes a current detection circuit 240. The current detection circuit 240 detects the value of the current flowing from the battery set to the motor 400 (hereinafter referred to as the battery current value). The current detection circuit 240 outputs a detection signal indicating the detected battery current value to the control circuit 120.

[0056] As shown in Figure 4B, the control circuit 120 acquires switch signals from the battery selector switch 71, remaining capacity indicator switch 73, lighting switch (not shown), main power switch 92, trigger switch 98, speed selector switch 96, direction of travel selector switch 94, and mechanical brake switch. The control circuit 120 also acquires the amount pulled of the drive lever 91 (hereinafter referred to as the trigger switch pull amount) from the drive lever 91. Based on the acquired switch signals, trigger switch pull amounts, and detection signals, the control circuit 120 controls the driving of the regulator 110 and the lighting LED 210, as well as the display of each display unit and the output of the buzzer 68. The buzzer 68 is located in the battery box 60.

[0057] Furthermore, the control circuit 120 generates a motor control signal based on each switch signal, the amount the trigger switch is pulled, and each detection signal, and outputs the generated motor control signal to the gate circuit 130. In this embodiment, the motor control signal is a pulse width modulation control signal (PWM signal).

[0058] The transport vehicle 1 is equipped with a second controller 300. The second controller 300 is housed in the motor unit 9 and controls the electromagnetic brake 410. The second controller 300 is connected to the control circuit 120 and the electromagnetic brake 410.

[0059] The second controller 300 includes a regulator 310. The regulator 310 receives power from the first and / or second battery sets and generates a power supply that is supplied to the various circuits included in the second controller 300.

[0060] The second controller 300 includes a signal determination circuit 330. The signal determination circuit 330 receives an electromagnetic brake control signal from the control circuit 120. For example, the electromagnetic brake control signal has two values, one of which corresponds to turning the electromagnetic brake 410 ON, and the other corresponding to turning the electromagnetic brake 410 OFF. The signal determination circuit 330 determines whether the electromagnetic brake control signal corresponds to turning the electromagnetic brake 410 ON or OFF, and outputs a determination signal indicating the determination result.

[0061] The second controller 300 includes a gate circuit 340. The gate circuit 340 is connected to a signal determination circuit 330 and receives a determination signal from the signal determination circuit 330. The second controller 300 comprises a switching element 350 and a diode 320. In this embodiment, the switching element 350 is an n-channel MOSFET. The drain of the switching element 350 is supplied with the voltage of the first and / or second battery set. The source of the switching element 350 is connected to the electromagnetic brake 410, and the gate of the switching element 350 is connected to the gate circuit 340. The anode of the diode 320 is connected to the ground line, and the cathode of the diode 320 is connected to the source of the switching element 350.

[0062] The gate circuit 340 turns the switching element 350 on or off according to the determination signal. When the switching element 350 is turned on, power is supplied to the electromagnetic brake 410, and the braking by the electromagnetic brake 410 is released. When the switching element 350 is turned off, power to the electromagnetic brake 410 is cut off, and braking by the electromagnetic brake 410 occurs. The gate circuit 340 turns off the switching element 350 if the determination signal corresponds to turning on the electromagnetic brake 410. The gate circuit 340 turns on the switching element 350 if the determination signal corresponds to turning off the electromagnetic brake 410.

[0063] <2. Main Processing> Next, the main processing performed by the control circuit 120 will be explained with reference to the flowchart in Figure 5.

[0064] In S10, the elapsed time during the current processing cycle is measured. In S20, it is determined whether the elapsed time in the current processing cycle has reached a predetermined control period. The control period is set in advance. If it is determined that the elapsed time has not reached the control period (S20: NO), the process returns to S10. If it is determined that the elapsed time has reached the control period (S20: YES), the process proceeds to S30.

[0065] In S30, the process of acquiring switch information is executed, and various switch signals are obtained. Details of the process of acquiring switch information will be described later. Next, in S40, power control processing is performed to set the power control signal to either on or off. Details of the power control processing will be described later.

[0066] Next, the S50 performs the battery information acquisition process and obtains information for the first to fourth battery packs, 70A to 70D. Details of the battery information acquisition process will be described later. Next, in S60, an error detection process is executed to determine whether the motor 400 should be stopped or decelerated. Details of the error detection process will be described later.

[0067] Next, in S70, the control mode setting process is executed to set the control mode of motor 400. Details of the control mode setting process will be described later. Next, S80 executes the control process for the electromagnetic brake 410, turning it on or off. Details of the control process for the electromagnetic brake 410 will be described later.

[0068] Next, S90 executes the control process for motor 400, driving or stopping motor 400. Details of the control process for motor 400 will be described later. Next, in S100, notification control processing is executed, and if the capacity of any of the 1st to 4th battery packs 70A to 70D falls below the capacity threshold, a capacity reduction is notified. Details of the notification control processing will be described later. After the execution of the notification control processing in S100, the elapsed time is reset, and the process returns to S10 to start the next processing cycle.

[0069] <2-1. Process for obtaining switch information> Referring to the flowchart in Figure 6, the switch information acquisition process performed by the control circuit 120 in S30 will be explained.

[0070] In S200, the trigger signal output from trigger switch 98 is acquired. Next, in S210, a signal indicating the amount the trigger switch has been pulled, output from the drive lever 91, is acquired. Next, in S220, the mechanical brake signal output from the mechanical brake switch is acquired.

[0071] Next, S230 acquires the main power signal output from the main power switch 92. Next, in S240, the speed switching signal output from the speed switching switch 96 is acquired. Next, in the S250, the direction of travel signal output from the direction of travel selector switch 94 is acquired.

[0072] Next, in S260, the battery switching signal output from the battery selector switch 71 is acquired. After that, the process proceeds to S40.

[0073] <2-2. Power Control Processing> Referring to the flowchart in Figure 7, the power control process performed by the control circuit 120 in S40 will be explained.

[0074] In S300, it is determined whether the main power switch 92 has been operated based on the main power signal acquired in S230. If it is determined that the main power switch 92 has been operated (S300: YES), the process proceeds to S310. If it is determined that the main power switch 92 has not been operated (S300: NO), this process is terminated.

[0075] In S310, it is determined whether the current power control signal is set to ON or not. If it is determined that the power control signal is set to ON (S310: YES), the process proceeds to S320. If it is determined that the power control signal is set to OFF (S310: NO), the process proceeds to S330.

[0076] In S320, the power control signal is changed to OFF, and this process is terminated. In S330, the power control signal is changed to ON, and this process is terminated.

[0077] <2-3. Battery Information Acquisition Process> Referring to the flowchart in Figure 8, the battery information acquisition process performed by the control circuit 120 in S50 will be explained.

[0078] In S350, detection signals indicating the voltage values ​​of the first to fourth battery packs 70A to 70D, output from the first to fourth voltage detection units 160A to 160D, are acquired. In S360, information about the first to fourth battery packs 70A to 70D is acquired via the battery communication unit 190. The information about the first to fourth battery packs 70A to 70D includes whether discharge is permitted or prohibited for each battery pack. After that, this process is terminated.

[0079] <2-4. Error detection process> Referring to the flowchart in Figure 9, the error determination process performed by the control circuit 120 in S60 will be explained.

[0080] In S400, it is determined whether the power control signal is on or off. If it is determined that the power control signal is on (S400:YES), the process proceeds to S410. If it is determined that the power control signal is off (S400:NO), the process proceeds to S480.

[0081] In S410, it is determined whether the trigger switch 98 is ON or OFF. If it is determined that the trigger switch 98 is ON (S410: YES), the process proceeds to S420. If it is determined that the trigger switch 98 is OFF (S410: NO), the process proceeds to S480.

[0082] S420 performs battery error detection. Specifically, if it receives discharge prohibition information or a discharge prohibition signal from a battery pack included in the selected battery set (either the first or second battery set), it sets the error status to "Yes".

[0083] Next, in S430, the overcurrent protection determination process is executed, and if an excessive current is flowing through motor 400, the error state is set to "Yes". Details of overcurrent protection will be described later. Next, in S440, the process for determining a Hall sensor error is executed. Specifically, based on the signals output from the three Hall sensors included in the position detection sensor 250, it is determined whether or not any of the Hall sensors are malfunctioning. If it is determined that any of the Hall sensors are malfunctioning, the error state is set to "Yes".

[0084] Next, in S450, the process for determining high-temperature protection of the FET is executed. Specifically, if the temperature obtained from the FET temperature detection unit 180 is above the temperature threshold, the error state is set to "Yes". The temperature threshold is a value based on the upper temperature limit at which the FET can operate normally.

[0085] Next, S460 performs the process to determine if there is a speeding error. Specifically, if the rotational speed calculated based on the position signal is greater than or equal to the speed threshold, the error state is set to "Yes".

[0086] Next, in S470, the overload protection check process is executed, and if the motor 400 is under excessive load, the error state is set to "Yes". Details of the overload protection check process will be described later. After that, this process is terminated.

[0087] On the other hand, in S480, the error status is set to "None". After that, this process is terminated.

[0088] <2-4-1. Overcurrent protection determination process> Referring to the flowchart in Figure 10, the overcurrent protection determination process performed by the control circuit 120 in S430 will be explained.

[0089] In the S500, check the current error status. Next, in S510, it is determined whether or not there are currently no errors. If it is determined that there are currently no errors (S510:YES), the process proceeds to S520. If it is determined that there are currently errors (S510:NO), this process is terminated.

[0090] In S520, the battery current value Ib is obtained based on the detection signal acquired from the current detection circuit 240. Next, in S530, an estimated value of the magnitude of the current flowing through motor 400 is calculated. Specifically, the battery current value Ib(A) obtained in S510 is divided by the duty cycle Du(%) of the PWM signal to calculate the estimated value Im(A). That is, the estimated value Im is calculated based on the formula Im = (Ib / Du) × 100.

[0091] Next, in S540, it is determined whether the battery current value Ib is equal to or greater than the first current threshold. If it is determined that the battery current value Ib is equal to or greater than the first current threshold (S540: YES), the process proceeds to S560. If it is determined that the battery current value Ib is less than the first current threshold (S540: NO), the process proceeds to S550.

[0092] In S550, it is determined whether the estimated value Im is greater than or equal to the second current threshold. If it is determined that the estimated value Im is greater than or equal to the second current threshold (S550: YES), the process proceeds to S560. If it is determined that the estimated value Im is less than the second current threshold (S550: NO), this process is terminated.

[0093] The first current threshold corresponds to the battery current value at which the power supply from the battery pack to the motor 400 must be immediately stopped. The second current threshold may be the same value as the first current threshold, or it may be a value greater than the first current threshold. The first and second current thresholds are pre-set and stored in memory 120b.

[0094] In S560, the error status is set to "Yes" and this process is terminated. In this embodiment, the battery current value Ib and the estimated value Im correspond to examples of current-dependent values ​​based on the discharge current flowing from the battery pack to the motor 400.

[0095] <2-4-2. Overload Protection Determination Process> Referring to the flowchart in Figure 11, the overload protection determination process performed by the control circuit 120 in S470 will be explained.

[0096] Figure 24 shows a transport vehicle 500 in reference. As shown in Figure 24, if the transport vehicle 500 is designed so that when it climbs a slope with a predetermined load weight, the motor torque > the braking force of the mechanical brake and electric brake, allowing it to barely climb the slope, the following problems arise.

[0097] In other words, when the transport vehicle 500 descends the slope with the maximum load capacity it can handle, the braking force may be insufficient, potentially causing the motor speed of the transport vehicle 500 to accelerate. Therefore, the control circuit of the transport vehicle 500 implements control to prevent the motor speed from accelerating when descending the slope. Specifically, the control circuit of the transport vehicle 500 limits the transport vehicle 500's ascent by stopping the motor to protect the user when it is climbing a slope with an excessive load. When the transport vehicle 500 is climbing a slope with an excessive load, the motor is overloaded. Therefore, the control circuit of the transport vehicle 500 determines whether the motor is overloaded, and if it is, it stops the motor.

[0098] However, as shown in Figure 25, the motor torque required for the transport vehicle 500 to overcome a step of a predetermined height may be greater than the motor torque required to climb the aforementioned slope. In other words, when the transport vehicle 500 overcomes the aforementioned step, the load on the motor may momentarily become greater than the load on the motor while climbing the slope. Therefore, if the motor becomes momentarily overloaded and the transport vehicle 500 stops its motor, the transport vehicle 500 will be unable to overcome the step. This could potentially hinder the work performed by the transport vehicle 500.

[0099] Therefore, the control circuit 120 of the transport vehicle 1 according to this embodiment protects the user by stopping the motor 400 if it is continuously overloaded. Here, when the transport vehicle 1 climbs the slope, the front wheels 3 rotate more than one full turn (i.e., 360°). On the other hand, when the transport vehicle 1 goes over the step, the front wheels 3 do not rotate one full turn. Therefore, the control circuit 120 determines whether the motor 400 is in an overloaded state based on the rotation information of the front wheels 3. Specifically, the control circuit 120 stops the motor 400 if it is continuously overloaded while the front wheels 3 are rotating one full turn.

[0100] First, in S600-S630, the same processing as in S500-S530 is performed. Next, S640 calculates the first mean value Ad. The first mean value Ad is the average value of the battery current value Ib acquired over a predetermined period. For example, the first mean value Ad is calculated using a moving average with 3-second intervals.

[0101] Next, in S650, the second mean value Am is calculated. The second mean value Am is the average of the estimated value Im calculated over a predetermined period. For example, the second mean value Am is calculated using a moving average with 3-second intervals.

[0102] Next, the S660 acquires rotational information for motor 400. This rotational information is the number of times the position signal has been updated. The number of times the position signal has been updated corresponds to the rotation angle of the motor 400's rotor.

[0103] Next, in S670, it is determined whether the first average value Ad is greater than or equal to the third current threshold. If it is determined that the first average value Ad is greater than or equal to the third current threshold (S670: YES), the process proceeds to S690. If it is determined that the first average value Ad is less than the third current threshold (S670: NO), the process proceeds to S680. The third current threshold corresponds to the battery current value when the motor 400 is overloaded, but it is not necessary to stop the motor 400 immediately. Therefore, the third current threshold is smaller than the first current threshold used to determine overcurrent protection.

[0104] In S680, it is determined whether the second mean value Am is greater than or equal to the fourth current threshold. If it is determined that the second mean value Am is greater than or equal to the fourth current threshold (S680:YES), the process proceeds to S690. If it is determined that the second mean value Am is less than the fourth current threshold (S680:NO), the process proceeds to S700. The fourth current threshold may be the same value as the third current threshold, or it may be a value greater than the third current threshold. The third and fourth current thresholds are pre-set and stored in memory 120b.

[0105] In S690, it is determined whether the number of updates indicated by the motor's rotation information is equal to or greater than the first rotation threshold. The first rotation threshold is the number of updates of the position signal corresponding to a predetermined rotational speed of the rotor. The predetermined rotational speed of the rotor corresponds to one rotation of the front wheel 3 (i.e., 360°). The ratio of the rotor's rotational speed to the front wheel 3's rotational speed is determined according to the gear ratio of gear 420. If it is determined that the number of updates indicated by the rotation information is equal to or greater than the first rotation threshold (S690:YES), the process proceeds to S710. If it is determined that the number of updates indicated by the rotation information is less than the first rotation threshold (S690:NO), this process is terminated.

[0106] In the S700, the motor rotation information is reset. This reduces the number of position signal updates. The process returns to 0. Then, the process terminates. In S710, the current error status is set to "Yes" and this process is terminated.

[0107] In this embodiment, the first average value Ad and the second average value Am correspond to an example of current-dependent values ​​based on the value of the discharge current flowing from the battery pack to the motor 400.

[0108] <2-5. Control Mode Setting Process> Referring to Figures 12A to 12C, the control mode setting process executed by the control circuit 120 in S70 will be described.

[0109] In S750, it is determined whether the power control signal is on or off. If it is determined that the power control signal is on (S750:YES), the process proceeds to S760. If it is determined that the power control signal is off (S750:NO), the process proceeds to S1040.

[0110] In S760, the driving conditions for the motor 400 are determined. In this embodiment, the driving conditions are that the trigger switch 98 is ON and the mechanical brake switch is OFF. That is, it is checked whether the trigger signal and the mechanical brake signal are ON or OFF.

[0111] Next, S770 detects the rotational speed of the motor 400 based on the position signal acquired from the position detection sensor 250. Next, in S780, it is determined whether or not the driving conditions for motor 400 are met. If it is determined that the driving conditions are met (S780:YES), the process proceeds to S790. If it is determined that the driving conditions are not met (S780:NO), the process proceeds to S830.

[0112] In S790, it is determined whether there is an error condition. Here, the error condition is determined in order to prevent motor 400 from being driven if there is an error condition. If it is determined that there is no error condition (S790:YES), the process proceeds to S800. If it is determined that there is an error condition (S790:NO), the process proceeds to S830.

[0113] In the S800, the operating time of motor 400 is measured. Next, in S810, the stop time for motor 400 is reset. Next, in S820, the drive determination for motor 400 is set to "allow".

[0114] Meanwhile, S830 resets the operating time of motor 400. Next, in S840, the stopping time of motor 400 is measured. Next, in S850, the drive detection for motor 400 is set to prohibited.

[0115] Next, in S860, the current control mode of motor 400 is determined. If the control mode is determined to be the initial mode, the process proceeds to S870. If the control mode is determined to be the standby mode, the process proceeds to S890. If the control mode is determined to be the drive mode, the process proceeds to S920. If the control mode is determined to be the first brake mode, the process proceeds to S970. If the control mode is determined to be the second brake mode, the process proceeds to S1020.

[0116] In S870, various variables are initialized. Next, in S880, the control mode is set to standby mode, and the process proceeds to S1050. In S890, it is determined whether the drive is permitted or not. If the drive is permitted (S890:YES), the process proceeds to S900. If the drive is prohibited (S890:NO), the process proceeds to S910.

[0117] In S900, the control mode is set to drive mode, and the process proceeds to S1050. In S910, various variables are initialized, and the process proceeds to S1050. In S920, it is determined whether the drive is permitted or not. If the drive is permitted (S920:YES), the process proceeds to S930. If the drive is prohibited (S920:NO), the process proceeds to S960.

[0118] In S930, a brake start determination process is executed to determine whether or not a brake start request has been made. Even if the drive determination is permitted, if the rotational speed of motor 400 is excessively high, braking force is generated for safety reasons. Details of the brake start determination process will be described later.

[0119] In S940, it is determined whether or not there is a brake start request. If it is determined that there is a brake start request (S940:YES), the process proceeds to S950. If it is determined that there is no brake start request (940:NO), the process proceeds to S1050.

[0120] In S950, the control mode is set to the first brake mode. That is, even if the drive determination is permitted, if there is a brake start request, the control mode is changed from drive mode to the first brake mode. Then, the process proceeds to S1050.

[0121] In S960, the control mode is set to the second brake mode. That is, if drive detection is prohibited during drive mode, the control mode is changed from drive mode to the second brake mode. Then, the process proceeds to S1050. In the first brake mode, the electric brake (specifically, a two-phase short-circuit brake) by the motor 400 is activated, but the electromagnetic brake 410 is energized and not activated. In the second brake mode, the electric brake by the motor 400 is activated, and the electromagnetic brake 410 is de-energized and then activated.

[0122] In S970, it is determined whether the drive is permitted or not. If the drive is permitted (S970:YES), the process proceeds to S980. If the drive is prohibited (S970:NO), the process proceeds to S1010.

[0123] In S980, a brake release determination process is executed, and if the electric brake by motor 400 can be released, the electric brake is released. Details of the brake release determination process will be described later. In S990, it is determined whether the electric brake is released or not. If it is determined that the electric brake is released (S990:YES), the process proceeds to S1000. If it is determined that the electric brake is not released (S990:NO), the process proceeds to S1050.

[0124] In the S1000, the control mode is set to drive mode. That is, if the electric brake is released in the first brake mode, the control mode is returned to drive mode. In S1010, the control mode is set to the second brake mode. That is, if drive detection is prohibited while in the first brake mode, the system switches to the second brake mode and stops motor 400.

[0125] In S1020, it is determined whether the electromagnetic brake 410 is de-energized or not. If the electromagnetic brake 410 is de-energized, it is recognized that the motor 400 is stopped. If it is determined that the electromagnetic brake 410 is de-energized (S1020: YES), the process proceeds to S1030. If it is determined that the electromagnetic brake 410 is energized (S1020: NO), the process proceeds to S1050.

[0126] In S1030, set the control mode to standby mode. In S1040, the control mode is set to the initial mode. S1050 calculates the processing time for each control mode. While details are omitted, the processing time is used as the starting point for saving the drive state and for branching conditions.

[0127] <2-5-1. First example of brake start determination process> Referring to the flowchart in Figure 13, a first example of the brake start determination process executed by the control circuit 120 in S930 will be described.

[0128] In S15, it is determined whether the rotational speed of motor 400 is greater than the set target rotational speed. Specifically, it is determined whether the rotational speed is greater than the target rotational speed + α, where α is a positive value. The process for setting the target rotational speed will be described later. If it is determined that the rotational speed is greater than the target rotational speed + α (S15: YES), the process proceeds to S25. If it is determined that the rotational speed is less than or equal to the target rotational speed + α (S15: NO), the process proceeds to S45.

[0129] In S25, it is determined whether the battery current value Id is less than a predetermined value. If it is determined that the battery current value Id is less than the predetermined value (S25:YES), the process proceeds to S35. If it is determined that the battery current value Id is equal to or greater than the predetermined value (S25:NO), the process proceeds to S45.

[0130] In S35, the system recognizes that the transport vehicle 1 has moved from flat ground to a downhill slope because the rotational speed is greater than the target rotational speed and the battery current value Id is less than a predetermined value. Since there is a possibility that the rotational speed will continue to accelerate, the brake start request is set to "Yes" and this process is terminated. In S45, the brake start request is set to "none," and this process ends.

[0131] <2-5-2. Second example of brake start determination process> Referring to the flowchart in Figure 14, a second example of the brake start determination process executed by the control circuit 120 in S930 will be described.

[0132] In S65, the same process as in S15 is performed. In S75, the same process as in S35 is performed, and in S85, the same process as in S45 is performed.

[0133] In the second example, unlike the first example, the condition for setting the brake start request to "Yes" is not that the battery current value Id is less than a predetermined value. In other words, in the second example, if the rotational speed is greater than the target rotational speed, the system recognizes that the transport vehicle 1 has moved from a flat road to a downhill slope, regardless of the magnitude of the battery current value Id.

[0134] <2-5-3. Brake release determination process> Referring to the flowchart in Figure 15, the brake release determination process executed by the control circuit 120 in S980 will be explained.

[0135] In S105, it is determined whether the rotational speed of motor 400 is less than half of the target rotational speed. If it is determined that the rotational speed is less than half of the target rotational speed (S105: YES), the process proceeds to S125. If it is determined that the rotational speed is greater than or equal to half of the target rotational speed (S105: NO), the process proceeds to S115.

[0136] In S115, it is determined whether the amount of electric brake control is less than a predetermined amount. If it is determined that the amount of electric brake control is less than a predetermined amount (S115: YES), the process proceeds to S125. If it is determined that the amount of control is equal to or greater than the predetermined amount, this process is terminated without releasing the electric brake.

[0137] In S125, the electric brake is released. That is, based on a decrease in rotational speed or a decrease in the amount of electric brake control, the system recognizes that the transport vehicle 1 has moved from a downhill slope to flat ground, and releases the electric brake.

[0138] <2-6. Electromagnetic Brake Control Processing> Referring to the flowchart in Figure 16, the electromagnetic brake control process performed by the control circuit 120 in S80 will be explained.

[0139] In S155, the current control mode is determined. If it is determined that the current control mode is the initial mode, the process proceeds to S165. If it is determined that the current control mode is the standby mode, the process proceeds to S185. If it is determined that the current control mode is the drive mode or the first brake mode, the process proceeds to S195. If it is determined that the current control mode is the second brake mode, the process proceeds to S205.

[0140] In S165, variables related to the operation of the electromagnetic brake 410 are initialized. Next, in S175, the electromagnetic brake 410 is de-energized. As a result, the electromagnetic brake 410 is activated, and the braking force from the electromagnetic brake 410 is applied to the motor 400.

[0141] In S185, the same process as in S175 is performed. In S195, the electromagnetic brake 410 is energized. This disables the electromagnetic brake 410, and the braking force from the electromagnetic brake 410 is no longer applied to the motor 400. Applying the braking force from the electromagnetic brake 410 to the motor 400 while it is running may cause the electromagnetic brake 410 to malfunction. Therefore, for safety reasons, the electromagnetic brake 410 is not activated until the rotational speed of the motor 400 has decreased sufficiently.

[0142] In S205, the stopped state of motor 400 is determined. Here, motor 400 is considered to be in a stopped state if its rotational speed is below a rotational threshold. The rotational threshold is a value small enough to consider motor 400 as being in a stopped state, for example, 250 revolutions per minute.

[0143] In S215, it is determined whether the motor 400 is stopped or not. If it is determined that the motor 400 is stopped (S215: YES), the process proceeds to S225. In S225, since the motor 400 is stopped, the electromagnetic brake 410 is de-energized and the electromagnetic brake 410 is activated.

[0144] On the other hand, if it is determined that the motor 400 is not in a stopped state (S215: NO), the process is terminated without activating the electromagnetic brake 410. For safety reasons, the electromagnetic brake 410 is not activated if the motor 400 is not in a stopped state.

[0145] <2-7. Motor Control Processing> Referring to the flowchart in Figure 17, the motor control process executed by the control circuit 120 in S90 will be explained.

[0146] In S255, the process for setting the target rotational speed is executed, and the target rotational speed of motor 400 is set based on the set control mode, direction of travel, speed mode, and the amount the trigger switch is pulled. Details of the process for setting the target rotational speed will be described later.

[0147] In S265, motor output control processing is executed, and a control signal is output to the gate circuit 130. Details of the motor output control processing will be described later.

[0148] <2-7-1. Setting the target rotation speed> Referring to the flowchart in Figure 18, the process of setting the target rotational speed that the control circuit 120 performs in S255 will be explained.

[0149] In S305, it is determined whether the power control signal is on or off. If it is determined that the power control signal is on (S305: YES), the process proceeds to S315. If it is determined that the power control signal is off (S305: NO), the process proceeds to S415.

[0150] In S315, it is determined whether the direction of travel switch 94 has been operated. If it is determined that the direction of travel switch 94 has been operated (S315: YES), the process proceeds to S385. If it is determined that the direction of travel switch 94 has not been operated (S315: NO), the process proceeds to S325.

[0151] In S325, it is determined whether the speed selector switch 96 has been operated. If it is determined that the speed selector switch 96 has been operated (S325: YES), the process proceeds to S335. If it is determined that the speed selector switch 96 has not been operated (S325: NO), the process proceeds to S435 without changing the direction of travel or the speed mode.

[0152] In S335, it is determined whether the currently set direction of travel is forward or not. If it is determined that the direction of travel is forward (S335: YES), the process proceeds to S345. If it is determined that the direction of travel is reverse (S335: NO), the process proceeds to S435 without changing the direction of travel or the speed mode. If the direction of travel is set to forward, the speed mode is changed according to the operation of the speed selector switch 96. On the other hand, if the direction of travel is set to reverse, the speed mode is not changed even if the speed selector switch 96 is operated.

[0153] In S345, the currently set speed mode is determined in order to change the speed mode. If the speed mode is set to high speed, the process proceeds to S355. If the speed mode is set to medium speed, the process proceeds to S365. If the speed mode is set to low speed, the process proceeds to S375.

[0154] In S355, the speed mode is changed from high speed to low speed, and the process proceeds to S435. In S365, the speed mode is changed from medium to high, and the process proceeds to S435.

[0155] In S375, the speed mode is changed from low speed to medium speed, and the process proceeds to S435. Furthermore, in S385, it is determined whether the currently set direction of travel is reverse or not. If it is determined that the direction of travel is reverse (S385: YES), the process proceeds to S395. If it is determined that the direction of travel is forward (S385: NO), the process proceeds to S405.

[0156] In S395, the direction of travel is changed from reverse to forward, and the process proceeds to S435. In S405, the direction of travel is changed from forward to reverse, and the process proceeds to S435. Additionally, in the S415, the initial setting is to set the direction of travel to forward. Next, in S425, the speed mode is set to low speed mode as an initial setting, and the process proceeds to S435.

[0157] In S435, the target rotational speed is set based on the current control mode, current direction of travel, current speed mode, and trigger switch pull amount. When the control mode is the first brake mode, the target rotational speed is set lower than when the control mode is the drive mode. When the control mode is the second brake mode, the target rotational speed is gradually brought closer to zero.

[0158] <2-7-2. Motor Output Control Processing> Referring to the flowchart in Figure 19, the control circuit 120 executes in S265. The output control process will be explained.

[0159] In S505, the current control mode is determined. If it is determined that the current control mode is the initial mode, the process proceeds to S515. If it is determined that the current control mode is the standby mode, the process proceeds to S535. If it is determined that the current control mode is the drive mode, the process proceeds to S555. If it is determined that the current control mode is the first brake mode or the second brake mode, the process proceeds to S575.

[0160] In S515, the motor drive process is initialized; that is, the variables related to the motor drive process are initialized. In step S525, a control signal is generated so that the total output of motor 400 becomes 0, and the generated control signal is output to gate circuit 130, ending this process.

[0161] In S535, the same process as in S515 is performed. In S545, the same process as in S525 is executed, and this process is terminated. In S555, proportional-integral control is performed based on the difference between the set target rotational speed and the current rotational speed to calculate the output duty cycle.

[0162] In S565, the output duty cycle calculated in S555 is set as the duty cycle of the PWM signal, and the PWM signal is generated. Then, the generated PWM signal is output to the gate circuit 130, and this process ends.

[0163] In the S575, the amount of electric brake control is calculated based on the difference between the set target rotational speed and the current rotational speed. In S585, the electric brake is applied according to the electric brake control amount calculated in S575. Specifically, the energizing time of the two-phase short-circuit brake is controlled according to the electric brake control amount. Then, this process is terminated.

[0164] <2-8. Notification Control Processing> Referring to the flowchart in Figure 20, the notification control process executed by the control circuit 120 in S100 will be explained.

[0165] In S605, it is determined whether the power control signal is on or off. If it is determined that the power control signal is on (S605: YES), the process proceeds to S615. If it is determined that the power control signal is off (S605: NO), the process proceeds to S665.

[0166] In step S615, the speed mode display process is executed, and the set speed mode is displayed in the speed mode display unit 97. Next, in S625, the process for displaying the direction of travel is executed, and the set direction of travel is displayed in the direction of travel display unit 95.

[0167] Next, S635 performs a battery capacity check process, verifying the battery capacity of each of the 1st to 4th battery packs 70A to 70B. Details of the battery capacity check process will be described later.

[0168] Next, S645 performs the battery capacity display process. If there are battery packs with reduced battery capacity, it displays the reduced battery capacity in the corresponding display unit among the first to fourth remaining capacity display units 72A to 72D. Details of the battery capacity display process will be described later.

[0169] Next, S655 performs buzzer output processing and outputs a buzzer sound from buzzer 68 if there is a battery pack with low battery capacity. After that, this process ends. Details of the buzzer output processing will be described later.

[0170] Additionally, in S665, all displays on the transport vehicle 1 are turned off. In S675, the output of buzzer 68 is turned off, and this process is terminated.

[0171] <2-8-1. Battery capacity check process> Referring to the flowchart in Figure 21, the battery capacity verification process performed by the control circuit 120 in S635 will be explained.

[0172] When motor 400 is momentarily overloaded, the battery voltage may also momentarily drop. In this case, the battery voltage will recover. Notifying the user of a momentary drop in battery voltage would be misleading. Therefore, if a voltage drop is continuously detected in any of the first to fourth battery packs 70A to 70D while the front wheel 3 rotates by a predetermined angle, a notification of a decrease in battery capacity will be issued. In this process, the capacity of the first to fourth battery packs 70A to 70D is checked while the front wheel 3 rotates by a predetermined angle.

[0173] S705 performs the same processing as S660. In S715, it is determined whether the current control mode is drive mode or not. If it is determined that the current control mode is drive mode (S715: YES), the process proceeds to S725. If it is determined that the current control mode is not drive mode (S715: NO), the process proceeds to S795.

[0174] In S725, it is determined whether the motor 400 has rotated above an angle threshold since the start of rotation. Immediately after the start of rotation, a voltage drop occurs due to the starting current. Here, in order to avoid detecting the voltage value at which the voltage drop due to the starting current occurs, it is determined whether or not the starting current is flowing. The angle threshold corresponds to the rotation angle at which it can be determined that the starting current has disappeared. If it is determined that the motor 400 has rotated above the angle threshold (S725:YES), the process proceeds to S735. If it is determined that the motor 400 has not rotated above the angle threshold (S725:NO), this process ends.

[0175] S735 acquires the voltage values ​​of each of the 1st to 4th battery packs 70A to 70D. In S745, it is determined whether each voltage value is below the voltage threshold. If it is determined that all voltage values ​​are above the voltage threshold (S745: NO), the process proceeds to S755. If it is determined that any voltage value is below the voltage threshold (S745: YES), the process proceeds to S775.

[0176] S755 resets the motor's rotation information. Next, S765 sets the capacity status of each of the 1st to 4th battery packs 70A to 70D to "Normal". After that, this process is terminated.

[0177] Furthermore, in S775, it is determined whether the number of updates indicated by the motor rotation information is equal to or greater than the second rotation threshold. The second rotation threshold corresponds to half a rotation (i.e., 180°) of the front wheel 3. If it is determined that the number of updates indicated by the motor rotation information is equal to or greater than the second rotation threshold (S775:YES), the process proceeds to S785. If it is determined that the number of updates indicated by the motor rotation information is less than the second rotation threshold (S775:NO), this process is terminated.

[0178] In S785, the capacity status of the low-capacity battery pack is set to "Low Capacity". After that, this process is terminated. Low-capacity battery packs are the 1st to 4th battery packs 70A~ This corresponds to a battery pack in the 70D category whose voltage value is below the voltage threshold. Furthermore, in S795, the same process as in S765 is executed, and then this process is terminated.

[0179] <2-8-2. Displaying Battery Capacity> Referring to the flowchart in Figure 22, the battery capacity display process performed by the control circuit 120 in S645 will be explained.

[0180] The S805 acquires the capacity status of each of the 1st to 4th battery packs, 70A to 70D. In S815, it is determined whether each capacity state is experiencing a capacity decrease. If it is determined that any capacity state is experiencing a capacity decrease (S815:YES), the process proceeds to S825. If it is determined that all capacity states are normal (S815:NO), the process proceeds to S835.

[0181] In S825, the low capacity is displayed in the display unit corresponding to the low-capacity battery pack among the first to fourth remaining capacity display units 72A to 72D. For example, the low capacity is indicated by blinking the LED of the remaining capacity display unit at a predetermined interval. After that, this process is terminated.

[0182] In S835, the LEDs of the 1st to 4th remaining capacity indicators 72A to 72D are turned off, and the capacity display is disabled. After that, this process is terminated.

[0183] <2-8-3. Buzzer Output Processing> Referring to the flowchart in Figure 23, the buzzer output processing performed by the control circuit 120 in S655 will be explained.

[0184] S905 and S915 perform the same processing as S805 and S815. The S925 notifies the presence of a low-capacity battery pack by outputting a buzzer sound from the buzzer 68. For example, the presence of a low-capacity battery pack is notified by switching the buzzer 68 on and off at predetermined intervals. After that, this process is terminated. In S935, the output of buzzer 68 is turned off, and this process is terminated.

[0185] <3.Operation> <3-1. Actions when climbing a slope> Figure 26 shows the changes in the second mean value Am, the first rotation angle, and the second rotation angle when the transport vehicle 1 climbs a slope with an excessive load. The first rotation angle is the rotation angle of motor 400 from the time it starts driving. The second rotation angle is the rotation angle of motor 400 when the second mean value Am is equal to or greater than the fourth current threshold. The fourth current threshold is set to 30A.

[0186] As shown in Figure 26, when the front wheels 3 of the transport vehicle 1 climb onto a slope, the second mean value Am begins to increase. When the second mean value Am exceeds the fourth current threshold, the second rotation angle begins to increase. The second rotation angle continues to increase, and when it reaches an angle equivalent to one rotation of the front wheels 3, the motor 400 stops. This allows the user to recognize that the load weight of the transport vehicle 1 is too heavy for uphill work.

[0187] <3-2. Actions taken when crossing steps> Figure 27 shows the changes in the second mean value Am, the first rotation angle, and the second rotation angle when transport vehicle 1 crosses a step with an excessive load.

[0188] As shown in Figure 27, when the front wheels 3 of the transport vehicle 1 go over a step, the second mean value Am is The second mean Am increases, and exceeds the fourth current threshold. However, after the front wheel 3 rides up onto the step, the second mean Am begins to decrease. After the front wheel 3 begins to rotate over the step, the second mean Am remains approximately constant. The second rotation angle begins to increase in response to the second mean Am exceeding the fourth current threshold. However, soon the second mean Am falls below the fourth current threshold, and the second rotation angle returns to zero. Therefore, the motor 400 does not stop; that is, the work of the transport vehicle 1 is not hindered.

[0189] <4. Effects> According to the embodiment described in detail above, the following effects are achieved. (1) By executing the overload protection determination process, the motor 400 can be stopped during uphill work by the transport vehicle 1 in an overloaded state. By executing the overcurrent protection determination process, the motor 400 can be stopped immediately in the event of an overcurrent. Consequently, the user and the motor 400 can be appropriately protected both during uphill work by the transport vehicle 1 in an overloaded state and in the event of an overcurrent.

[0190] (2) In the overcurrent protection determination process, the motor 400 is determined to be overloaded if it is continuously overloaded for the duration of one rotation of the front wheel 3. This allows for the exclusion of momentary overloads of the motor 400 and enables accurate determination of the motor 400's overload during uphill climbing under overloaded conditions.

[0191] (3) As the front wheel 3 rotates half a turn, the battery pack voltage value remains below the voltage threshold, and a decrease in capacity is notified. This allows the user to recognize when the battery pack needs to be charged and when the capacity has decreased.

[0192] (Other embodiments) Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0193] (a) In the above embodiment, in the overcurrent protection determination process, the determination in S540 may be performed based on a first mean value Ad instead of the battery current value Ib. Also, in the overcurrent protection determination, the determination in S550 may be performed based on a second mean value Am instead of the estimated value Im. Furthermore, although both determinations in S540 and S550 were performed in the overcurrent protection determination process, only one of them may be performed.

[0194] (b) In the above embodiment, in the overload protection determination process, the determination in S670 may be performed based on the battery current value Ib instead of the first average value Ad. Also, in the overload protection determination, the determination in S680 may be performed based on the estimated value Im instead of the second average value Am. Furthermore, although both determinations in S670 and S680 were performed in the overload protection determination process, only one of them may be performed.

[0195] (c) In the overcurrent protection determination process, the determination in S540 may be performed based on an accumulation counter instead of the battery current value Ib. The accumulation counter is an example of a current-dependent value. The accumulation counter is calculated by accumulating an added value corresponding to the battery current value Ib at a predetermined period. If the battery current value Ib is greater than a predetermined value, the added value is a positive value, and if the battery current value Ib is less than a predetermined value, the added value is a negative value. Similarly, in the overload protection determination process, the determination in S670 may be performed based on an accumulation counter instead of the first mean value Ad.

[0196] (d) In the above embodiment, the battery current value Id was detected and the motor current value Im was estimated from the detected battery current value Id. However, in addition to detecting the battery current value Id, the three-phase motor The motor current value Im may be detected directly. Alternatively, the three-phase motor current value Im may be detected, and the battery current value Id may be estimated from the detected motor current value Im.

[0197] (e) In the overload protection determination process, the determination in S670 may be performed based on the voltage value of the battery pack included in the selected battery set. Specifically, in S670, it may be determined whether the voltage value is less than or equal to the overload voltage threshold, and if the voltage value is less than or equal to the overload voltage threshold, the process may proceed to S690. That is, as long as the front wheel 3 is continuously rotating by a predetermined angle, the power supply from the selected battery set to the motor 400 is stopped in accordance with the fact that the voltage value remains less than or equal to the overload voltage threshold. Overload can be determined and power supply to the motor 400 stopped based on the voltage value instead of the current-dependent value. The overload voltage threshold corresponds to an example of the first voltage threshold in this disclosure.

[0198] (f) In the above embodiment, the rotation state of the front wheel 3 is not directly detected, and the rotation state of the motor 400 corresponding to the rotation state of the front wheel 3 is detected by the position detection sensor 250. However, the disclosure is not limited to this. A rotation sensor may be installed on the shaft of the front wheel 3 to directly detect the rotation state of the front wheel 3. In this case, in S690 of the overload protection determination process, it is determined whether the detected rotation angle of the front wheel 3 is 1 rotation or more. Also, in S775 of the battery capacity confirmation process, it is determined whether the detected rotation angle of the front wheel 3 is half a rotation or more.

[0199] (g) Motor 400 may be a brushed motor. In this case, since the position detection sensor 250 cannot be provided, a rotation sensor may be installed on the shaft of the front wheel 3 to directly detect the rotation state of the front wheel 3. Alternatively, motor 400 may be a sensorless motor that does not use the detection signal of a Hall element. In this case, the rotation speed is calculated from the induced voltage and motor current generated in the windings of motor 400.

[0200] (h) In the above embodiment, in the overload protection determination shown in Figure 11, the overload was determined based on the battery current value Ib, the motor current value Im, and the rotation information, and the power supply from the battery pack to the motor 400 was stopped. However, the overload may be determined by another method. For example, in control to match the rotation speed of the motor 400 to a target rotation speed, an overload may be determined if the decrease amount continuously exceeds a decrease threshold while the front wheel 3 is rotating continuously by a predetermined angle. The decrease amount is the amount by which the actual rotation speed has decreased relative to the target rotation speed.

[0201] (i) In addition, in constant rotation control of the motor 400, if the rise amount continuously exceeds the rise threshold while the front wheel 3 is rotating continuously by a predetermined angle, it may be determined that there is an overload. The rise amount is the amount by which the second input voltage value rises relative to the first input voltage value. The first input voltage value is the input voltage value required to rotate the motor 400 at the target rotation speed when the transport vehicle 1 is traveling on flat ground. The second input voltage value is the voltage value actually input to the motor 400.

[0202] (j) Multiple functions of one component in the above embodiment 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. Furthermore, some of the configurations of the above embodiment may be omitted. Furthermore, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments. [Explanation of symbols]

[0203] 1... Transport vehicle, 3... Front wheel, 5... Rear wheel, 9... Motor unit, 60... Battery box, 68... Buzzer, 70A... First battery pack, 70A, 70B... Second battery pack, 70 A~70D...1st~4th battery packs, 71...Battery selector switch, 72A~72D...1st~4th remaining capacity display unit, 90...Operating device, 91...Drive lever, 92...Main power switch, 94...Direction of travel selector switch, 95...Direction of travel display unit, 96...Speed ​​selector switch, 97...Speed ​​mode display unit, 98...Trigger switch, 100...1st controller, 120...Control circuit, 120a...CPU, 120b...Memory, 160A~160D...1st~4th voltage detection unit, 190...Battery communication unit, 240...Current detection circuit, 250...Position detection sensor, 300...2nd controller, 400...Motor, 410...Electromagnetic brake, 420...Gear.

Claims

1. A handle configured to be grasped by the user, A battery mounting section configured for mounting a battery, A motor configured to rotate by receiving power from the battery attached to the battery mounting section, A wheel configured to be driven by the aforementioned motor, A current detection unit configured to detect a supply current value corresponding to the magnitude of the current supplied from the battery to the motor, A rotation detection sensor configured to directly or indirectly detect the rotation angle of the wheel, The system comprises a control unit configured to control the drive of the motor, The control unit, While maintaining a state in which the value based on the supply current value detected by the current detection unit remains above the current threshold, the power supply to the motor is stopped based on the fact that the rotation angle of the wheel detected by the rotation detection sensor has deviated from a first angular range. It is structured in such a way. Transport vehicle.

2. A handle configured to be grasped by the user, A battery mounting section configured for mounting a battery, A motor configured to rotate by receiving power from the battery attached to the battery mounting section, A wheel configured to be driven by the aforementioned motor, A voltage detection unit configured to detect a battery voltage value corresponding to the magnitude of the battery voltage, A rotation detection sensor configured to directly or indirectly detect the rotation angle of the wheel, The system comprises a control unit configured to control the drive of the motor, The control unit, While the battery voltage value detected by the voltage detection unit remains below a first voltage threshold, the power supply to the motor is stopped based on the rotation angle of the wheel detected by the rotation detection sensor having deviated from a first angular range. It is structured in such a way. Transport vehicle.

3. Further comprising a notification unit configured to notify of a decrease in the capacity of the battery, The control unit is configured to maintain a state in which the battery voltage value detected by the voltage detection unit remains below a second voltage threshold, and to cause the notification unit to notify of the decrease in capacity based on the fact that the rotation angle of the wheel detected by the rotation detection sensor has shifted within a second angular range. The transport vehicle according to claim 2.

4. The first angular range is greater than 360°. A transport vehicle according to claim 1 or 2.

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