Assist control device

Abstract

To prevent assist force from being accidently outputted.SOLUTION: An assist control device 100 controls an electric motor 21 that assists running of a moving body. The assist control device 100 comprises an operation switch 3 and a control part 10. The operation switch 3 is configured to be brought into an ON-state when the switch is operated by a user and to be brought into an OFF-state when the operation by the user is released. When the operation switch 3 is in the ON-state, the control part 10 controls the electric motor 21 so that assist force is outputted.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an assist control device. [Background technology]

[0002] It has been proposed to attach a drive unit to a mobile body that moves at low speed, such as a pallet truck, a hand lift truck, a hand truck, or a wheelchair, to improve the performance of the mobile body. The drive unit includes an electric motor for driving the wheels to rotate, and a control device for controlling the electric motor. The electric motor outputs an assist force to assist the human power when the mobile body is propelled by human power.

[0003] For example, the control device disclosed in Patent Document 1 is configured to cause an electric motor to output an assist force in accordance with the acceleration of a moving object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4495444 Summary of the Invention [Problem to be solved by the invention]

[0005] In a control device configured as described above, when the user leans on the moving body or places the moving body on an inclined road surface and the moving body starts moving, there is a risk that the electric motor will output an unintended assist force in response to the acceleration.

[0006] An object of the present invention is to prevent the output of an unintended assist force. [Means for solving the problem]

[0007] An assist control device according to one aspect of the present invention controls an electric motor that assists the traveling of a mobile object. This assist control device includes an operation switch and a control unit. The operation switch is configured to be turned on when operated by a user and to be turned off when the user's operation is released. The control unit controls the electric motor to output an assist force when the operation switch is on.

[0008] According to this configuration, the electric motor will not output an assist force unless the user operates the operation switch to turn it on, thereby preventing the electric motor from outputting an unintended assist force.

[0009] Preferably, the operation switch includes a forward switch and a reverse switch, and the control unit controls the electric motor to output a forward assist force when the forward switch is in an on state, and also controls the electric motor to output a reverse assist force when the reverse switch is in an on state.

[0010] Preferably, the operation switch is configured to be in either a first on state or a second on state when operated by a user, and to be in an off state when the user's operation is released. The control unit controls the electric motor to output a forward assist force when the operation switch is in the first on state, and controls the electric motor to output a reverse assist force when the operation switch is in the second on state.

[0011] Preferably, the movable body further includes an operating handle that extends upward and is swingable. The assist control device further includes a tilt angle detection unit that detects a tilt angle of the operating handle with respect to a vertical axis. The control unit controls the electric motor based on the tilt angle detected by the tilt angle detection unit.

[0012] Preferably, the control unit determines whether the tilt angle is in a first range, a second range having a tilt angle greater than the first range, or a third range having a tilt angle greater than the second range. Tilt angle When it is determined that the difference is within the third range, the assist by the electric motor is stopped.

[0013] Preferably, the tilt angle detection unit is configured with at least one of an acceleration sensor, a gyro sensor, and a limit switch.

[0014] Preferably, when the control unit determines that the operation switch has been switched from an on state to an off state while the moving object is traveling, the control unit executes a first braking process to stop the moving object.

[0015] Preferably, the control unit executes the first braking process after a predetermined waiting time has elapsed.

[0016] Preferably, when the control unit determines that both the forward movement switch and the reverse movement switch are turned on while the moving body is traveling, the control unit executes a second braking process to stop the moving body.

[0017] Preferably, the control unit executes a third brake process to stop the moving body when it determines that the reverse switch has been turned on while the moving body is moving forward, or when it determines that the forward switch has been turned on while the moving body is moving backward.

[0018] Preferably, the control unit determines that the operation switch has been switched between the first on state and the second on state while the moving body is traveling, and then performs a second control to stop the moving body. 3 Execute the braking process.

[0019] Preferably, the control unit executes the braking process with a braking force corresponding to the assist force of the electric motor.

[0020] Preferably, the control unit calculates the assist force based on moving object information about the moving object, such as the acceleration, speed, and weight of the moving object.

[0021] Preferably, the control unit stops calculating the assist force from the start of the assist control until the moving object reaches a predetermined vehicle speed, and sets the assist force to a predetermined value.

[0022] Preferably, the control unit stops calculating the assist force until a preset time has elapsed since the start of the assist control, and sets the assist force to a preset value.

[0023] Preferably, the control unit sets the assist force to zero when the moving object remains stationary even after a preset time has elapsed. [Effects of the Invention]

[0024] According to the present invention, it is possible to prevent an unintended assist force from being output. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a side view showing a portion of a pallet truck. [Figure 2] FIG. [Figure 3] 10 is a flowchart showing the processing of a control unit. [Figure 4] 10 is a flowchart showing the processing of a control unit. [Figure 5] 10 is a flowchart showing the processing of a control unit. [Figure 6] 10 is a flowchart showing the processing of a control unit. [Figure 7] 10 is a flowchart showing the processing of a control unit. [Figure 8] 10 is a flowchart showing the processing of a control unit. [Figure 9] 10 is a flowchart showing the processing of a control unit. [Figure 10] 4 is a timing chart for explaining the running of a pallet truck. DETAILED DESCRIPTION OF THE INVENTION

[0026] An assist control device according to this embodiment will be described below with reference to the drawings. The assist control device (hereinafter also simply referred to as a "control device") is configured to control an electric motor that assists the traveling of a mobile object. The control device is provided in the mobile object. The mobile object is traveled by human power. The mobile object travels at a low speed. The mobile object is configured to transport an object. The concept of an object includes people, etc. Examples of such mobile objects include a pallet truck, a hand lift truck, a hand truck, and a wheelchair. In this embodiment, the mobile object is a pallet truck.

[0027] <Pallet truck> Fig. 1 is a side view of a pallet truck 200 equipped with a control device. As shown in Fig. 1, the pallet truck 200 has a pallet truck body 210 and a drive unit 20. The pallet truck body 210 has a loading platform (a pair of fork arms) 201, an operating handle 202, and a plurality of wheels 204. The drive unit 20 is attached to this pallet truck body 210.

[0028] The pallet truck 200 moves forward when it moves to the left in Fig. 1, and moves backward when it moves to the right in Fig. 1. In other words, when the user pulls the operating handle 202, the pallet truck 200 moves forward, and when the user pushes the operating handle 202, the pallet truck 200 moves backward.

[0029] The operating handle 202 extends upward from the loading platform 201. The operating handle 202 is configured to be swingable around a base end 202a. By swinging the operating handle 202, the operating handle 202 is tilted with respect to a vertical axis V. The tilt angle θ formed between the operating handle 202 and the vertical axis V can be changed by swinging the operating handle 202 around the base end 202a.

[0030] The range of the tilt angle θ formed by the operating handle 202 and the vertical axis V can be divided into a first range R1, a second range R2, and a third range R3. The tilt angle θ in the first range R1 is the smallest, the tilt angle θ in the second range R2 is larger than the tilt angle θ in the first range R1, and the tilt angle θ in the third range R3 is larger than the tilt angle θ in the second range R2.

[0031] Although not particularly limited, for example, the first range R1 can be 0°≦θ<20°, the second range R2 can be 20°≦θ<60°, and the third range R3 can be 60°≦θ≦90°. In this way, when the operating handle 202 is within the first range R1, it can be considered that the operating handle 202 is in an upright state. Furthermore, when the operating handle 202 is within the second range R2, it can be considered that the operating handle 202 is in an inclined state. Furthermore, when the operating handle 202 is within the third range R3, it can be considered that the operating handle 202 is in a reclined state.

[0032] <Drive unit> 2, the drive unit 20 includes an electric motor 21, a motor driver 22, a reducer 23, a battery 24 (see FIG. 1), drive wheels 203, and a control device 100. The drive unit 20 does not necessarily have to have drive wheels 203. In this case, the drive unit 20 drives and rotates at least one of the wheels 204 of the pallet truck 200 instead of the drive wheels 203.

[0033] The electric motor 21 outputs an assist force for assisting the travel of the pallet truck 200. The electric motor 21 drives the drive wheels 203 to rotate.

[0034] The motor driver 22 controls the power supplied from the battery 24 to the electric motor 21. The motor driver 22 is connected to the control device 100 so as to be able to communicate with the control device 100 via wire or wirelessly. The motor driver 22 drives the electric motor 21 in response to a control signal from the control device 100.

[0035] The reducer 23 reduces the rotation speed of the electric motor 21 and transmits the rotation to the drive wheels 203. The reducer 23 is made up of, for example, a plurality of gears.

[0036] <Control device> The control device 100 is configured to control the electric motor 21. The control device 100 includes an operation switch 3, a tilt angle detection unit 4, and a control unit 10.

[0037] The operation switch 3 is attached to, for example, the operation handle 202. The operation switch 3 is configured to be turned on when operated by the user and turned off when the user's operation is released. In other words, the operation switch 3 is a momentary type switch.

[0038] The operation switch 3 includes, for example, a forward switch 3a and a reverse switch 3b. Both the forward switch 3a and the reverse switch 3b are momentary type switches.

[0039] When a user wants to receive assist force while traveling forward, the user operates the forward switch 3a. For example, the forward switch 3a is a push button switch. The user presses the forward switch 3a. The forward switch 3a is in the on state only while it is being pressed.

[0040] Furthermore, when the user releases the operation of the forward switch 3a, the forward switch 3a is turned off. For example, when the user removes the finger that is pressing the forward switch 3a from the forward switch 3a, the forward switch 3a is turned off. Note that the forward switch 3a is not limited to a push button switch, and may be, for example, a switch that uses a touch sensor, such as a capacitance touch switch.

[0041] When a user wants to receive assistance power while reversing, the user operates the reverse switch 3b. For example, the reverse switch 3b is a push button switch. The user presses the reverse switch 3b. The reverse switch 3b is in the on state only while it is pressed.

[0042] Furthermore, when the user releases the operation of the reverse switch 3b, the reverse switch 3b is turned off. For example, when the user releases the finger that is pressing the reverse switch 3b from the reverse switch 3b, the reverse switch 3b is turned off. Note that the reverse switch 3b is not limited to a push button switch, and may be, for example, a switch that uses a touch sensor, such as a capacitance touch switch.

[0043] When the user does not need the assist force, he or she does not operate both the forward switch 3a and the reverse switch 3b.

[0044] The tilt angle detection unit 4 is configured to detect the tilt angle θ of the operating handle 202 relative to the vertical axis V. The tilt angle detection unit 4 can be configured with, for example, an acceleration sensor. The tilt angle detection unit 4 may also be configured with a gyro sensor, or with both an acceleration sensor and a gyro sensor. The tilt angle detection unit 4 can also be configured with, for example, a tilt sensor, an angle sensor, or a limit switch. When a limit switch is used, the tilt angle detection unit 4 detects the tilt range rather than the tilt angle itself.

[0045] The control unit 10 is configured by, for example, a computer (for example, a microcomputer) equipped with a CPU (Central Processing Unit) and a ROM (Read Only Memory). The ROM stores programs for performing various calculations. The CPU executes the programs stored in the ROM.

[0046] The control unit 10 is configured to control the electric motor 21. When the operation switch 3 is in the on state, the control unit 10 causes the electric motor 21 to output an assist force.

[0047] In detail, when the control unit 10 determines that the forward movement switch 3a is in the on state, it controls the electric motor 21 to output a forward movement assist force. As a result, the electric motor 21 outputs the forward movement assist force to rotate the drive wheels 203. The process in which the control unit 10 causes the electric motor 21 to output the forward movement assist force is referred to as the "forward movement assist process."

[0048] Furthermore, when the control unit 10 determines that the reverse switch 3b is in the on state, it controls the electric motor 21 to output an assist force for reverse. As a result, the electric motor 21 outputs the assist force for reverse to rotate the drive wheels 203. This process by which the control unit 10 causes the electric motor 21 to output the assist force for reverse is referred to as "reverse assist process."

[0049] The control unit 10 can calculate the forward assist force and the reverse assist force based on, for example, moving body information about the pallet truck 200. The moving body information can include, for example, the acceleration of the pallet truck 200, the weight of the pallet truck 200 including the load, the rolling resistance, and power loss.

[0050] Specifically, the control unit 10 can calculate the assist force Fa by the following equation (1).

[0051]

number

[0052] The control unit 10 can calculate F in the above formula (1) using the following formula (2).

[0053]

number

[0054] The control unit 10 can calculate the power loss Fv using the following equation (3).

[0055]

number

[0056] Furthermore, the control unit 10 can calculate the rolling resistance Fr using the following equation (4).

[0057]

number

[0058] The control unit 10 controls the electric motor 21 by outputting a control signal to the motor driver 22. The control unit 10 determines whether the pallet truck 200 is traveling or not, for example, based on the speed or acceleration of the pallet truck 200. The control unit 10 also determines whether the pallet truck 200 is moving forward or backward, based on the speed or acceleration of the pallet truck 200.

[0059] When the control unit 10 determines that the forward movement switch 3a is in the OFF state and the reverse movement switch 3b is also in the OFF state, it does not cause the electric motor 21 to output the forward movement assist force or the reverse movement assist force. In this case, the pallet truck 200 is run solely by human power. This type of running of the pallet truck solely by human power is hereinafter referred to as "free running."

[0060] The control unit 10 controls the electric motor 21 based on the tilt angle θ of the operating handle 202. First, the control unit 10 determines whether the tilt angle θ of the operating handle 202 with respect to the vertical axis V is in the first range R1, the second range R2, or the third range R3.

[0061] When the control unit 10 determines that the tilt angle θ is within the first range R1, it does not cause the electric motor 21 to output an assist force even if the forward movement switch 3a is in the on state. In other words, when the tilt angle θ is within the first range R1, the control unit 10 does not execute the forward movement assist process. In this case, the user can allow the pallet truck 200 to travel freely. Note that when the reverse movement switch 3b is in the on state, the control unit 10 causes the electric motor 21 to output a reverse movement assist force as usual. In other words, the control unit 10 executes the reverse movement assist process.

[0062] Furthermore, when the control unit 10 determines that the tilt angle θ is within the second range R2, it causes the electric motor 21 to output an assist force as usual for both forward and reverse movement. That is, when the tilt angle θ is within the second range R2, the control unit 10 can execute the forward movement assist process and the reverse movement assist process.

[0063] Furthermore, when the control unit 10 determines that the tilt angle θ is within the third range R3, it does not cause the electric motor 21 to output an assist force, even if the forward switch 3a is in the on state or the reverse switch 3b is in the on state. Thus, when the tilt angle θ is within the third range R3, the control unit 10 does not execute either the forward assist process or the reverse assist process. Therefore, the pallet truck 200 can only travel freely.

[0064] When the control unit 10 determines that the operation switch 3 has switched from an on state to an off state while the pallet truck 200 is traveling, it executes a first brake process to stop the pallet truck 200. For example, when the forward switch 3a switches from an on state to an off state while the pallet truck 200 is moving forward, or when the reverse switch 3b switches from an on state to an off state while the pallet truck 200 is moving backward, the control unit 10 executes the first brake process. When the control unit 10 determines that the pallet truck 200 has stopped, it releases the first brake process.

[0065] Examples of the first braking process include regenerative braking of the electric motor 21 and short braking of the electric motor 21. The control unit 10 outputs a control signal to the motor driver 22 so as to execute regenerative braking or short braking of the electric motor 21. Note that a braking device may be installed in the pallet truck 200, and the control unit 10 may control this braking device to stop the pallet truck 200.

[0066] The control unit 10 executes the first brake process after a predetermined waiting time has elapsed. That is, when the control unit 10 determines that the forward switch 3a has switched from an on state to an off state or the reverse switch 3b has switched from an on state to an off state, the control unit 10 does not execute the first brake process immediately, but executes the first brake process after a predetermined waiting time has elapsed.

[0067] Although not particularly limited, the predetermined waiting time can be, for example, about 0.3 to 1.0 seconds. The predetermined waiting time can also be a fixed time stored in advance in the control unit 10. The control unit 10 can also set the waiting time according to the vehicle speed or weight of the pallet truck 200. For example, the control unit 10 can shorten the waiting time as the vehicle speed increases. The control unit 10 can also shorten the waiting time as the weight (including the load) of the pallet truck 200 increases.

[0068] When the control unit 10 determines that both the forward switch 3a and the reverse switch 3b are turned on while the pallet truck 200 is traveling, it executes a second braking process to stop the pallet truck 200. When the control unit 10 determines that the pallet truck 200 has stopped, it releases the second braking process.

[0069] For example, when the pallet truck 200 is traveling freely, if the user operates (presses) both the forward switch 3a and the reverse switch 3b, the control unit 10 executes the second brake process.

[0070] In addition, when the user operates the forward switch 3a to cause the pallet truck 200 to travel in forward assist mode, if the user operates the reverse switch 3b while still operating the forward switch 3a, the control unit 10 executes the second brake processing.

[0071] In addition, when the user operates the reverse switch 3b to cause the pallet truck 200 to travel in a reverse assist mode, if the user operates the forward switch 3a while still operating the reverse switch 3b, the control unit 10 executes the second brake processing.

[0072] The second braking process may be, for example, regenerative braking of the electric motor 21 or short braking of the electric motor 21. The control unit 10 outputs a control signal to the motor driver 22 so that regenerative braking or short braking of the electric motor 21 is performed. A braking device may be provided on the pallet truck 200, and the control unit 10 may control this braking device to stop the pallet truck 200. The braking force in the second braking process may be the same as or different from the braking force in the first braking process.

[0073] The control unit 10 may execute a third brake process to stop the pallet truck 200 when it determines that the reverse switch 3b has been turned on while the pallet truck 200 is moving forward, or when it determines that the forward switch 3a has been turned on while the pallet truck 200 is moving backward. As with the second brake process, the third brake process may include regenerative braking of the electric motor 21, short braking of the electric motor 21, braking by a braking device, etc. When it determines that the pallet truck 200 has stopped, the control unit 10 cancels the third brake process.

[0074] The control unit 10 executes the first to third braking processes with braking forces corresponding to the assisting force of the electric motor 21. For example, the control unit 10 increases the braking forces in the first to third braking processes as the assisting force of the electric motor 21 increases. Note that the control unit 10 may execute the first to third braking processes with a constant braking force regardless of the magnitude of the assisting force of the electric motor 21.

[0075] [Control method] Next, an example of processing executed by the control unit 10 will be described with reference to the flowchart of FIG.

[0076] First, the control unit 10 determines whether the tilt angle θ of the operating handle 202 is in the first range R1, the second range R2, or the third range R3, based on the tilt angle θ detected by the tilt angle detection unit 4. Specifically, the control unit 10 determines whether the tilt angle θ is in the first range R1 (step S1).

[0077] When the control unit 10 determines that the tilt angle θ is within the first range R1 (Yes in step S1), it executes a first process (step S2) which will be described later.

[0078] Next, the control unit 10 determines whether the tilt angle θ is within the second range R2 (step S3). If the control unit 10 determines that the tilt angle θ is within the second range R2 (Yes in step S3), it executes a second process (step S5) to be described later. On the other hand, if the control unit 10 determines that the tilt angle θ is not within the second range R2 (No in step S3), it executes a third process (step S8) to be described later.

[0079] The first process will be described with reference to the flowcharts of FIGS.

[0080] First, the control unit 10 determines whether or not "the forward switch 3a is in the OFF state and the reverse switch 3b is in the OFF state" (step S21). When the control unit 10 determines that "the forward switch 3a is in the OFF state and the reverse switch 3b is in the OFF state" (Yes in step S21), it then determines whether or not the pallet truck 200 is traveling (step S22).

[0081] When the control unit 10 determines that the pallet truck 200 is not traveling (No in step S22), it does not cause the electric motor 21 to output assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S23). Then, the control unit 10 executes a process to disable the brake flag (step S24). Note that the brake flag is enabled when the operation switch 3 is operated while the truck is traveling, as will be described later.

[0082] On the other hand, when the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S22), it determines whether or not the brake flag is valid (step S25).

[0083] When the control unit 10 determines that the brake flag is enabled (Yes in step S25), it executes the first brake process (step S26). On the other hand, when the control unit 10 determines that the brake flag is not enabled (No in step S25), it does not cause the electric motor 21 to output an assist force. In other words, the control unit 10 puts the pallet truck 200 into a state where it can travel freely (step S27).

[0084] When the control unit 10 determines in step S21 that the forward switch 3a is not in the OFF state and the reverse switch 3b is not in the OFF state (No in step S21), it then determines whether the forward switch 3a is in the ON state and the reverse switch 3b is in the OFF state (step S28).

[0085] When the control unit 10 determines that "the forward switch 3a is in the on state and the reverse switch 3b is in the off state" (Yes in step S28), it then determines whether the pallet truck 200 is traveling (step S29).

[0086] When the control unit 10 determines that the pallet truck 200 is not traveling (No in step S29), it does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S30). Then, the control unit 10 executes a process to disable the brake flag (step S31).

[0087] On the other hand, when the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S29), it then determines whether or not the electric motor 21 is rotating in the forward direction (step S32). If the electric motor 21 is rotating in the forward direction, the pallet truck 200 moves forward. For this reason, in step S32, the control unit 10 may determine whether or not the pallet truck 200 is moving forward, instead of determining whether or not the electric motor 21 is rotating in the forward direction.

[0088] When the control unit 10 determines that the electric motor 21 is rotating in the forward direction (Yes in step S32), it does not output the assist force from the electric motor 21. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S33). Then, the control unit 10 executes a process to enable the brake flag (step S34).

[0089] When the control unit 10 determines that the electric motor 21 is not rotating in the forward direction (No in step S32), that is, when it determines that the electric motor 21 is rotating in the reverse direction, the control unit 10 does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state where it can run freely (step S35). Note that in step S35, the control unit 10 may execute a third brake process to stop the running of the pallet truck 200 instead of putting the pallet truck 200 into a state where it can run freely.

[0090] When the control unit 10 determines in step S28 that the forward switch 3a is not in the ON state and the reverse switch 3b is not in the OFF state (No in step S28), it determines whether the forward switch 3a is in the OFF state and the reverse switch 3b is in the ON state (step S36), as shown in FIG. 5.

[0091] When the control unit 10 determines that "the forward switch 3a is in the OFF state and the reverse switch 3b is in the ON state" (Yes in step S36), it then determines whether the pallet truck 200 is traveling (step S37).

[0092] When the control unit 10 determines that the pallet truck 200 is not traveling (No in step S37), it executes a reverse assist process (step S38). That is, the control unit 10 causes the electric motor 21 to output a reverse assist force. Then, the control unit 10 executes a process to activate a brake flag (step S39).

[0093] On the other hand, when the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S37), it then determines whether the electric motor 21 is rotating in the reverse direction (step S40). If the electric motor 21 is rotating in the reverse direction, the pallet truck 200 moves backward. For this reason, in step S40, the control unit 10 may determine whether the pallet truck 200 is moving backward, instead of determining whether the electric motor 21 is rotating in the reverse direction.

[0094] When the control unit 10 determines that the electric motor 21 is rotating in the reverse direction (Yes in step S40), it executes a reverse assist process (step S41). That is, the control unit 10 causes the electric motor 21 to output a reverse assist force. As a result, the pallet truck 200 travels in a reverse assist mode. Then, the control unit 10 executes a process to enable a brake flag (step S42).

[0095] When the control unit 10 determines that the electric motor 21 is not rotating in the reverse direction (No in step S40), that is, when it determines that the electric motor 21 is rotating in the forward direction, the control unit 10 does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S43). Note that in step S43, the control unit 10 may execute a third brake process to stop the travel of the pallet truck 200 instead of putting the pallet truck 200 into a state in which it can travel freely.

[0096] When the control unit 10 determines in step S36 that the forward switch 3a is not in the OFF state and the reverse switch 3b is not in the ON state (No in step S36), it then determines whether the forward switch 3a is in the ON state and the reverse switch 3b is in the ON state (step S44).

[0097] When the control unit 10 determines that "the forward switch 3a is on and the reverse switch 3b is on" (Yes in step S44), it then determines whether the pallet truck 200 is traveling (step S45).

[0098] When the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S45), it executes the second brake process (step S46). On the other hand, when the control unit 10 determines that the pallet truck 200 is not traveling (No in step S45), it does not cause the electric motor 21 to output an assist force. In other words, the control unit 10 puts the pallet truck 200 into a state where it can travel freely (step S47).

[0099] The second process will be described with reference to the flowcharts of FIGS.

[0100] Note that the processing from step S51 to step S57 in the second processing is the same as the processing from step S21 to step S27 in the first processing described above, and therefore the description thereof will be omitted. Also, the processing from step S66 to step S77 in the second processing is the same as the processing from step S36 to step S47 in the first processing described above, and therefore the description thereof will be omitted.

[0101] The control unit 10 determines whether or not "the forward switch 3a is in the ON state and the reverse switch 3b is in the OFF state" (step S58).

[0102] When the control unit 10 determines that "the forward switch 3a is on and the reverse switch 3b is off" (Yes in step S58), it then determines whether the pallet truck 200 is traveling (step S59).

[0103] When the control unit 10 determines that the pallet truck 200 is not traveling (No in step S59), it executes forward movement assist processing (step S60). That is, the control unit 10 causes the electric motor 21 to output a forward movement assist force. Then, the control unit 10 executes processing to enable the brake flag (step S61).

[0104] On the other hand, when the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S59), it then determines whether or not the electric motor 21 is rotating in the forward direction (step S62). Note that in step S62, the control unit 10 may determine whether or not the pallet truck 200 is moving forward, instead of determining whether or not the electric motor 21 is rotating in the forward direction.

[0105] When the control unit 10 determines that the electric motor 21 is rotating in the forward direction (Yes in step S62), it executes a forward movement assist process (step S63). That is, the control unit 10 causes the electric motor 21 to output a forward movement assist force. Then, the control unit 10 executes a process to enable a brake flag (step S64).

[0106] When the control unit 10 determines that the electric motor 21 is not rotating in the forward direction (No in step S62), that is, when it determines that the electric motor 21 is rotating in the reverse direction, the control unit 10 does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state where it can run freely (step S65). Note that in step S65, the control unit 10 may execute a third brake process to stop the running of the pallet truck 200 instead of putting the pallet truck 200 into a state where it can run freely.

[0107] The third process will be described with reference to the flowcharts of FIGS.

[0108] In addition, steps S81 to S82 in the third process 95 The process up to this point is the same as steps S21 to S24 in the first process described above. 35 Furthermore, the processing from step S104 to step S107 in the third processing is the same as the processing from step S44 to step S47 in the first processing described above, so the description thereof will be omitted.

[0109] As shown in FIG. 9, the control unit 10 determines whether or not "the forward switch 3a is in the OFF state and the reverse switch 3b is in the ON state" (step S96).

[0110] When the control unit 10 determines that "the forward switch 3a is in the OFF state and the reverse switch 3b is in the ON state" (Yes in step S96), it then determines whether the pallet truck 200 is traveling (step S97).

[0111] When the control unit 10 determines that the pallet truck 200 is not traveling (No in step S97), it does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S98). Then, the control unit 10 executes a process to disable the brake flag (step S99).

[0112] On the other hand, when the control unit 10 determines that the pallet truck 200 is traveling (Yes in step S97), it then determines whether the electric motor 21 is rotating in the reverse direction (step S100). Note that in step S100, the control unit 10 may determine whether the pallet truck 200 is moving backward, instead of determining whether the electric motor 21 is rotating in the reverse direction.

[0113] When the control unit 10 determines that the electric motor 21 is rotating in the reverse direction (Yes in step S100), it does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S101). Then, the control unit 10 executes a process to enable the brake flag (step S102).

[0114] When the control unit 10 determines that the electric motor 21 is not rotating in the reverse direction (No in step S100), that is, when it determines that the electric motor 21 is rotating in the forward direction, the control unit 10 does not cause the electric motor 21 to output an assist force. That is, the control unit 10 puts the pallet truck 200 into a state in which it can travel freely (step S103). Note that in step S103, the control unit 10 may execute a third brake process to stop the travel of the pallet truck 200 instead of putting the pallet truck 200 into a state in which it can travel freely.

[0115] Next, the traveling state of the pallet truck 200 will be described with reference to the timing chart in Figure 10. First, up until time t1, no human power is applied to the pallet truck 200. Also, because the forward switch 3a and reverse switch 3b are in the off state, the electric motor 21 is not outputting any assist force. Therefore, the pallet truck 200 is stopped.

[0116] From time t1 to t2, human power is applied to the pallet truck 200, causing the pallet truck 200 to move forward. Note that, because the forward switch 3a and the reverse switch 3b are in the OFF state, the electric motor 21 is not outputting an assist force. In other words, the pallet truck 200 is traveling freely.

[0117] At time t2, the forward movement switch 3a is turned on, so the control unit 10 executes the forward movement assist process and the electric motor 21 outputs a forward movement assist force, causing the pallet truck 200 to travel with forward movement assist.

[0118] At time t3, the forward movement switch 3a is switched from the on state to the off state, and so when a predetermined waiting time has elapsed and time t4 arrives, the control unit 10 executes the first brake process, causing the pallet truck 200 to decelerate and eventually come to a stop.

[0119] At time t5, the pallet truck 200 stops, so the control unit 10 releases the first brake process. At this time, the electric motor 21 is not outputting an assist force.

[0120] At time t6, the reverse switch 3b is turned on, and the control unit 10 executes the reverse assist process.

[0121] At time t7, the reverse switch 3b switches from the on state to the off state, so when a predetermined waiting time has elapsed and time t8 arrives, the control unit 10 executes the first braking process. Then, at time t9, both the forward switch 3a and the reverse switch 3b are switched on, so the control unit 10 executes the second braking process. Note that in this example, the braking force exerted by the second braking process is greater than the braking force exerted by the first braking process. The first and second braking processes cause the pallet truck 200 to slow down and eventually come to a stop.

[0122] [Variations] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0123] (a) In the above embodiment, the operation switch 3 includes two switches, the forward switch 3a and the reverse switch 3b, but the configuration of the operation switch 3 is not limited to this. For example, the operation switch 3 may be configured with a single switch. In this case, the operation switch 3 switches between three states: a first on state, a second on state, and an off state.

[0124] The first on state of the operation switch 3 corresponds to the on state of the forward switch 3a and the off state of the reverse switch 3b in the above embodiment. The second on state of the operation switch 3 corresponds to the on state of the reverse switch 3b and the off state of the forward switch 3a in the above embodiment. The off state of the operation switch 3 corresponds to the off state of the forward switch 3a and the off state of the reverse switch 3b in the above embodiment.

[0125] The user can operate the operation switch 3 to either the first on state or the second on state. When the user's operation is released, the operation switch 3 is configured to return to the off state. In other words, the operation switch 3 is a momentary type switch.

[0126] Specifically, the operation switch 3 is a toggle switch. The operation switch 3 is in a first ON state only while the user presses the operation switch 3 to the first side, and when the user releases the operation switch 3, the operation switch 3 is in an OFF state. Also, the operation switch 3 is in a second ON state only while the user presses the operation switch 3 to the second side opposite the first side, and when the user releases the operation switch 3, the operation switch 3 is in an OFF state.

[0127] When the control unit 10 determines that the operation switch 3 is in the first on state, it executes a forward movement assist process. That is, the control unit 10 controls the electric motor 21 to output a forward movement assist force. In this way, when the operation switch 3 is in the first on state, the control unit 10 executes the same process as when the forward movement switch 3a in the above embodiment is in the on state.

[0128] When the control unit 10 determines that the operation switch 3 is in the second ON state, it executes a reverse assist process. That is, the control unit 10 controls the electric motor 21 to output a reverse assist force. In this way, when the operation switch 3 is in the second ON state, the control unit 10 executes the same process as when the reverse switch 3b in the above embodiment is in the ON state.

[0129] The control unit 10 does not execute the second brake process in the above embodiment, but executes the first and third brake processes.

[0130] Specifically, the control unit 10 executes the first brake processing when it determines that the operation switch 3 has switched from the first on state or the second on state to the off state while the pallet truck 200 is traveling. More specifically, the control unit 10 executes the first brake processing when it determines that the operation switch 3 has switched from the first on state to the off state while the pallet truck 200 is moving forward. Furthermore, the control unit 10 executes the first brake processing when it determines that the operation switch 3 has switched from the second on state to the off state while the pallet truck 200 is moving backward.

[0131] When the control unit 10 determines that the operation switch 3 has been switched between the first on state and the second on state while the pallet truck 200 is traveling, the control unit 10 executes a third brake process.

[0132] Specifically, the control unit 10 executes the third brake process when it determines that the operation switch 3 has switched from the first on state to the second on state while the pallet truck 200 is moving forward. Also, the control unit 10 executes the third brake process when it determines that the operation switch 3 has switched from the second on state to the first on state while the pallet truck 200 is moving backward.

[0133] In the operation switch 3 of this modified example, there is no state equivalent to "forward switch 3a is on and reverse switch 3b is on" in the above embodiment, so the control unit 10 does not execute the processing of steps S44 to S47, steps S74 to S77, and steps S104 to S107 in the above embodiment.

[0134] (b) The control unit 10 may stop calculating the assist force from the start of assist control until the pallet truck 200 reaches a preset vehicle speed, or until a preset time has elapsed since the start of assist control. Instead of calculating the assist force, the control unit 10 may set the assist force to a preset value. Note that the preset value does not have to be a constant value. Also, the assist control may start when the forward switch 3a or the reverse switch 3b is turned on.

[0135] The control unit 10 may set the assist force to zero when it determines that the pallet truck 200 is still stopped after a preset time has elapsed. The control unit 10 may also control the assist force based on both the vehicle speed and the elapsed time. [Explanation of symbols]

[0136] 3: Operation switch 3a: Forward switch 3b: Reverse switch 4: Tilt angle detector 10: Control section 21: Electric motor 100: Control device 200: Pallet truck 202: Operating handle R1: First range R2: Second range R3: Third range

Claims

1. An assist control device that controls an electric motor that assists the travel of a moving body having an operating handle that extends upward and is configured to be swingable, an operation switch configured to be turned on when operated by a user and turned off when the operation by the user is released; a control unit that controls the electric motor to output an assist force when the operation switch is in an on state; an inclination angle detection unit that detects an inclination angle of the operating handle relative to a vertical axis; Equipped with The control unit controls the electric motor based on the tilt angle detected by the tilt angle detection unit. Assist control device.

2. The operation switches include a forward switch and a reverse switch, the control unit controls the electric motor to output a forward assist force when the forward movement switch is in an on state, and controls the electric motor to output a reverse assist force when the reverse movement switch is in an on state. The assist control device according to claim 1 .

3. the operation switch is configured to be in either a first on state or a second on state when operated by a user, and to be in an off state when the operation by the user is released, the control unit controls the electric motor to output a forward assist force when the operation switch is in a first on state, and controls the electric motor to output a reverse assist force when the operation switch is in a second on state. The assist control device according to claim 1 .

4. the control unit determines whether the tilt angle is in a first range, a second range having a tilt angle greater than the first range, or a third range having a tilt angle greater than the second range, and stops assist by the electric motor when it determines that the tilt angle is in the third range. The assist control device according to any one of claims 1 to 3.

5. The tilt angle detection unit is configured with at least one of an acceleration sensor, a gyro sensor, and a limit switch. The assist control device according to any one of claims 1 to 4.

6. the control unit, when determining that the operation switch has been switched from an on state to an off state while the moving body is traveling, executes a first brake process to stop the moving body. The assist control device according to any one of claims 1 to 5.

7. The control unit executes the first brake process after a predetermined waiting time has elapsed. The assist control device according to claim 6.

8. the control unit executes a second brake process to stop the moving body when it determines that both the forward movement switch and the reverse movement switch are in an on state while the moving body is traveling. The assist control device according to claim 2 .

9. the control unit executes a third brake process to stop the moving body when it determines that the reverse switch has been turned on while the moving body is moving forward or when it determines that the forward switch has been turned on while the moving body is moving backward. The assist control device according to claim 2 or 8.

10. the control unit, when determining that the operation switch has switched between a first on state and a second on state while the moving body is traveling, executes a third brake process to stop the moving body. The assist control device according to claim 3 .

11. the control unit executes the braking process with a braking force corresponding to the assist force of the electric motor. The assist control device according to any one of claims 6 to 10.

12. the control unit calculates an assist force based on moving body information related to the moving body.

12. The assist control device according to claim 1.

13. the control unit stops calculating the assist force from the start of the assist control until the moving object reaches a predetermined vehicle speed, and sets the assist force to a predetermined value. The assist control device according to claim 12.

14. the control unit stops calculating the assist force until a preset time has elapsed since the start of the assist control, and sets the assist force to a preset value. The assist control device according to claim 12 or 13.

15. the control unit sets the assist force to zero when the moving object remains stationary even after a preset time has elapsed. The assist control device according to claim 13 or 14.

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