Control device for electrically assisted vehicle and electrically assisted vehicle

Abstract

To provide a control device that is able to reduce a burden on a user even when an electric assist vehicle is in a manually pushed state.SOLUTION: The control device is configured such that: (A) when it is determined that an electric assist vehicle is in a manually pushed state and an assist request in the manually pushed state is made by a user, the control device performs switching to a first mode for generating torque in a direction in which a motor of the electric assist vehicle advances the electric assist vehicle according to a vehicle speed of the electric assist vehicle in a first range relating to the vehicle speed of the electric assist vehicle; and (B) when it is determined that the electric assist vehicle is in the manually pushed state and the assist request in the manually pushed state is not made by the user or a brake request in the manually pushed state is made by the user, the control device performs switching to a second mode for controlling a braking operation according to a vehicle speed of the electric assist vehicle in a second range relating to the vehicle speed of the electric assist vehicle.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control technique for an electrically assisted vehicle when being pushed by hand. [Background technology]

[0002] Electrically assisted bicycles, which are an example of electrically assisted vehicles, are heavier than bicycles without assist functions because they have additional components such as a motor and battery. For this reason, there is technology available that provides an electrically assisted mode for electrically assisted bicycles, which operates the motor when the bicycle is pushed by hand in response to a switch on the control panel, thereby reducing the burden on the user when the bicycle is dismounted and pushed by hand.

[0003] For example, Patent Document 1 discloses an electrically assisted bicycle having an electric motor capable of applying a pushing assist torque to the wheel when the bicycle is being pushed. Specifically, this electrically assisted bicycle is equipped with a control unit capable of operating in three modes: a first mode in which the electric motor does not apply torque to the wheel, a second mode in which the electric motor applies a stay assist torque to the wheel to keep the electrically assisted bicycle in place, and a third mode in which the electric motor applies a pushing assist torque to the wheel, and the first, second, and third modes can be selected using an operation unit that can be operated by the rider's fingers. However, with this technology, while assistance when pushing the bicycle alone can reduce the burden on the user when riding on flat ground or climbing hills, it cannot reduce the burden on the user when descending hills, such as hand fatigue caused by using mechanical brakes or physical fatigue from supporting the electrically assisted bicycle.

[0004] Furthermore, Patent Document 2 discloses an electric bicycle equipped with a control unit that switches between an assist mode in which a first auxiliary driving force is applied for traveling and a second mode in which a second auxiliary driving force is applied for pushing or self-propelling, and a sensor that outputs speed information related to the speed of the electric bicycle or rotation speed information indicating the number of rotations per unit time of the electric motor. While the second mode is being executed, the control unit determines whether the electric bicycle is descending a slope based on the speed information or rotation speed information, and if it determines that the electric bicycle is descending a slope, it reduces the second auxiliary driving force of the electric motor. However, because the control unit detects inclination through calculation, there is a possibility that an inclination may be erroneously recognized due to an inaccurate or abnormal slope calculation, resulting in inappropriate operation such as reducing the second auxiliary driving force when the electric bicycle is not descending a slope.

[0005] Furthermore, Patent Document 3 discloses a walking assist device having wheels or tracks. Specifically, the walking assist device includes a motor that drives the wheels or tracks, a control unit that controls the motor in response to the user's operating force, and a speed limiting unit that limits the rotation of the wheels or tracks, or the speed of the walking assist device, regardless of the operating force, when it is determined that the rotation of the wheels or tracks or the speed of the walking assist device is greater than or equal to a predetermined value. The speed limiting unit brakes the rotation of the motor and stops the wheels or tracks when the rotation of the wheels or tracks or the speed of the walking assist device exceeds a predetermined value. This walking assist device is designed to slow down if the user's speed increases too much to prevent the user from falling, but it is essentially an assist device, and when the speed is below a predetermined value, it controls the motor to assist in response to the user's operating force.

[0006] Furthermore, Patent Document 4 discloses a motor control device having an inverter that powers or regeneratively brakes the motor of an electrically assisted vehicle, and a control unit that determines a motor control mode based on the direction of human power and the direction of motor rotation when a user pushes or pulls the electrically assisted vehicle by hand, and controls the inverter to cause the motor to generate torque based on the human power in the determined control mode.The control mode is described as being one of forward motor powering, forward regenerative or negative motoring, negative regenerative or forward motoring, and negative motor powering.This motor control device switches the motor control mode based on the direction of human power and the direction of motor rotation, but basically generates torque based on human power, and there are cases where the torque corresponding to the human power is not appropriate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-100541 [Patent Document 2] Japanese Patent Application Publication No. 2019-155963 [Patent Document 3] International Publication No. 2014 / 188726 [Patent Document 4] Japanese Patent Application Publication No. 2019-142460 [Patent Document 5] International Publication No. 2012 / 086459 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, one object of the present invention is to provide a novel technique for reducing the burden on the user even when the electrically assisted vehicle is being pushed by hand. [Means for solving the problem]

[0009] This control device for an electric assist vehicle switches to a first mode in which the motor of the electric assist vehicle generates torque in a direction that moves the electric assist vehicle forward in accordance with the vehicle speed of the electric assist vehicle within a first range of vehicle speeds when it is determined that (A) the electric assist vehicle is in a hand-pushed state and the user has requested assistance in the hand-pushed state, and (B) in which it is determined that the electric assist vehicle is in a hand-pushed state and the user has not requested assistance in the hand-pushed state or has requested braking in the hand-pushed state, to a second mode in which braking operation is controlled in accordance with the vehicle speed of the electric assist vehicle within a second range of vehicle speeds of the electric assist vehicle. [Effects of the Invention]

[0010] According to one aspect, the burden on the user can be reduced even when the electrically assisted vehicle is being pushed by hand. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the appearance of an electrically assisted bicycle. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a motor drive control device. [Figure 3] FIG. 3 is a diagram illustrating an example of a functional block configuration related to the hand-push control unit. [Figure 4] FIG. 4 is a diagram showing a schematic diagram of the assumed riding state of the power-assisted bicycle in the second mode and the corresponding control content. [Figure 5] FIG. 5 is a diagram showing a schematic diagram of the assumed riding state of the power-assisted bicycle in the third mode and the corresponding control content. [Figure 6] FIG. 6 is a diagram showing a processing flow of mode switching in the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of a control mode in the third mode according to the second embodiment. [Figure 8] FIG. 8 illustrates an example of a processing flow in the third mode according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of a control mode in the third mode according to the third embodiment. [Figure 10] FIG. 10 illustrates an example of a processing flow in the third mode according to the third embodiment. [Figure 11] FIG. 11 is a diagram schematically illustrating an example of a control mode in the third mode of the fourth and fifth embodiments. [Figure 12] FIG. 12 is a diagram illustrating an example of a control mode in the third mode according to the fourth embodiment. [Figure 13] FIG. 13 illustrates an example of a processing flow in the third mode according to the fourth embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of a processing flow of the basic control processing. [Figure 15] FIG. 15 illustrates an example of a processing flow in the third mode according to the fifth embodiment. [Figure 16] FIG. 16 illustrates an example of a processing flow in the third mode according to the fifth embodiment. [Figure 17] FIG. 17 illustrates an example of a processing flow in the third mode according to the fifth embodiment. [Figure 18] FIG. 18 is a diagram illustrating an example of a control mode in the second mode according to the sixth embodiment. [Figure 19] FIG. 19 illustrates an example of a processing flow in the second mode according to the sixth embodiment. [Figure 20] FIG. 20 is a diagram illustrating an example of a control mode in the second mode according to the seventh embodiment. [Figure 21] FIG. 21 illustrates an example of a processing flow in the second mode according to the seventh embodiment. [Figure 22] FIG. 22 is a diagram schematically illustrating an example of a control mode in the second mode of the eighth embodiment. [Figure 23] FIG. 23 illustrates an example of a processing flow in the second mode according to the eighth embodiment. [Figure 24]FIG. 24 is a diagram schematically illustrating an example of a control aspect in the second mode of the ninth embodiment. [Figure 25] FIG. 25 illustrates an example of a processing flow in the second mode according to the ninth embodiment. [Figure 26] FIG. 26 is a diagram showing the external appearance (part) of an electrically assisted bicycle according to a tenth embodiment. [Figure 27] FIG. 27 is a diagram illustrating an example of the configuration of a motor drive control device according to a tenth embodiment. [Figure 28] FIG. 28 is a diagram showing a processing flow of mode switching in the tenth embodiment. [Figure 29] FIG. 29 is a diagram schematically showing the installation positions of sensors in the eleventh embodiment. [Figure 30] FIG. 30 is a diagram showing the appearance of an electrically assisted bicycle according to a twelfth embodiment. [Figure 31] FIG. 31 is a diagram illustrating an example of the configuration of a motor drive control device according to a twelfth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described using an example of an electrically assisted bicycle, which is an example of an electrically assisted vehicle. However, electrically assisted vehicles are not limited to electrically assisted bicycles, and may be, for example, carts, wheelchairs, walking aids, elevators, etc. Furthermore, electrically assisted vehicles may have not only two wheels but also three wheels.

[0013] [Embodiment 1] 1 is an external view showing an example of an electrically assisted bicycle, which is an example of an electrically assisted vehicle according to this embodiment. This electrically assisted bicycle 1 is equipped with a motor drive device. The motor drive device includes a battery pack 101, a motor drive control device 102, a torque sensor 103, a pedal rotation sensor 104, a motor 105, an operation panel 106, a brake sensor 107, and a riding prevention mechanism 108.

[0014] The power-assisted bicycle 1 also has a handle post 110, a front wheel, a rear wheel, a headlight, a freewheel, a transmission, and the like.

[0015] The battery pack 101 is, for example, a lithium ion secondary battery, but may be other types of batteries, such as a lithium ion polymer secondary battery, a nickel-metal hydride battery, etc. The battery pack 101 supplies power to the motor 105 via the motor drive control device 102, and is also charged by the regenerated power from the motor 105 via the motor drive control device 102 during regeneration.

[0016] Torque sensor 103 is provided near the crankshaft, detects the pedal force applied by the driver, and outputs the detection result to motor drive control device 102. Similarly to torque sensor 103, pedal rotation sensor 104 is provided near the crankshaft, and outputs a signal corresponding to rotation to motor drive control device 102.

[0017] Motor 105 is, for example, a well-known three-phase DC brushless motor, and is attached to, for example, the front wheel of power-assisted bicycle 1. Motor 105 rotates the front wheel, and its rotor is connected to the front wheel so that the rotor rotates in response to the rotation of the front wheel. Furthermore, motor 105 is equipped with a rotation sensor such as a Hall element, and outputs rotor rotation information (i.e., a Hall signal) to motor drive control device 102.

[0018] The brake sensor 107 detects the brake operation by the driver and outputs a signal related to the brake operation to the motor drive control device 102 .

[0019] When a user is riding the power-assisted bicycle 1, the motor drive control device 102 performs a predetermined calculation based on signals from the motor 105 rotation sensor, torque sensor 103, pedal rotation sensor 104, brake sensor 107, etc., to control the power driving of the motor 105 and also control the regenerative braking of the motor 105. Furthermore, when the user is pushing or pulling the power-assisted bicycle 1 by hand and assistance is possible, the motor drive control device 102 performs a predetermined calculation based on signals from the motor 105 rotation sensor, etc., to determine the control mode of the motor 105, and controls the motor 105 to power driving or regenerative braking in that control mode. Note that instead of regenerative control, braking force may be generated by consuming current without flowing to the battery, or mechanical braking force may be generated as described in other embodiments.

[0020] The operation panel 106 receives, for example, instruction inputs from the user regarding whether or not to provide assistance (i.e., turning the power switch on and off), and if assistance is provided, inputs such as the desired assist ratio, and outputs the instruction inputs to the motor drive control device 102. In this embodiment, the operation panel 106 is assumed to have a push assist button that instructs the power-assisted bicycle 1 to assist in pushing the power-assisted bicycle 1 by hand.

[0021] The riding prevention mechanism 108 is a mechanism for preventing a user from sitting on the saddle. For example, in an initial state, the riding prevention mechanism 108 is stored, allowing the user to sit on the saddle and pedal as normal. However, when the user wants to have the motor 105 assist the power-assisted bicycle 1 while pushing or pulling it by hand, the user deploys the riding prevention mechanism 108 near the saddle, putting it into a deployed state that prevents the user from sitting on the saddle, as shown schematically in FIG. 1 . In this deployed state, the riding prevention mechanism 108 outputs a signal to the motor drive control device 102 indicating that it has been deployed. In this embodiment, when the motor drive control device 102 is powered on and receives such a signal, it recognizes that the power-assisted bicycle 1 is in a push state in which the power-assisted bicycle 1 is being pushed or pulled by hand and is capable of providing assistance, etc.

[0022] In this embodiment, it is assumed that the user is prevented from sitting on the saddle, but in some cases, a load sensor provided under the saddle may be used to determine whether the user is sitting on the saddle, thereby determining whether the bicycle is being pushed by hand. Furthermore, it may be possible to determine whether the bicycle is being pushed by hand by using other mechanisms.

[0023] Next, a configuration related to the motor drive control device 102 according to this embodiment is shown in FIG.

[0024] The motor drive control device 102 has a controller 1020 and a FET (Field Effect Transistor) bridge 1030. The FET bridge 1030 includes a high-side FET (Suh) and a low-side FET (Sul) that perform switching for the U phase of the motor 105, a high-side FET (Svh) and a low-side FET (Svl) that perform switching for the V phase of the motor 105, and a high-side FET (Swh) and a low-side FET (Swl) that perform switching for the W phase of the motor 105. This FET bridge 1030 functions as an inverter that powers or regeneratively brakes the motor 105.

[0025] The controller 1020 also has a calculation unit 1021, a pedal rotation input unit 1022, a state input unit 1023, a motor rotation input unit 1024, a variable delay circuit 1025, a motor drive timing generation unit 1026, a torque input unit 1027, a brake input unit 1028, and an AD (Analog-Digital) input unit 1029.

[0026] The calculation unit 1021 performs a predetermined calculation using inputs from the operation panel 106 (e.g., assist on / off, hand-push assist button on / off, etc.), pedal rotation input from the pedal rotation sensor 104, input from the state input unit 1023, input from the motor rotation input unit 1024, input from the torque input unit 1027, input from the brake input unit 1028, and input from the AD input unit 1029, and outputs the results to the motor drive timing generation unit 1026 and the variable delay circuit 1025. The calculation unit 1021 includes a memory 10211, which stores various data used in the calculations and data in the middle of processing. Furthermore, the calculation unit 1021 may be realized by a processor executing a program, in which case the program may be recorded in the memory 10211. The memory 10211 may also be provided separately from the calculation unit 1021.

[0027] The pedal rotation input unit 1022 digitizes a signal representing pedal rotation from the pedal rotation sensor 104 and outputs the digitized signal to the calculation unit 1021. The state input unit 1023 digitizes a signal representing whether or not the ride prevention mechanism 108 is in the deployed state and outputs the digitized signal to the calculation unit 1021.

[0028] The motor rotation input unit 1024 digitizes a signal (e.g., rotation phase angle, rotation direction, etc.) related to the rotation of the motor 105 (in this embodiment, rotation of the front wheel) from the Hall signal output by the motor 105 and outputs the signal to the calculation unit 1021. The motor rotation input unit 1024 may, for example, calculate and output the vehicle speed of the power-assisted bicycle 1 (e.g., a positive vehicle speed indicates a forward speed, and a negative vehicle speed indicates a reverse speed) from the motor rotation input. The torque input unit 1027 digitizes a signal corresponding to the pedal force from the torque sensor 103 and outputs the signal to the calculation unit 1021. The brake input unit 1028 digitizes a signal indicating whether the brake is applied from the brake sensor 107 and outputs the signal to the calculation unit 1021. The AD input unit 1029 digitizes the output voltage from the secondary battery and outputs the signal to the calculation unit 1021.

[0029] The calculation unit 1021 outputs a lead-angle value as a calculation result to the variable delay circuit 1025. The variable delay circuit 1025 adjusts the phase of the Hall signal based on the lead-angle value received from the calculation unit 1021 and outputs the adjusted phase to the motor drive timing generation unit 1026. The calculation unit 1021 outputs a PWM code corresponding to a PWM (Pulse Width Modulation) duty ratio as a calculation result to the motor drive timing generation unit 1026. The motor drive timing generation unit 1026 generates and outputs switching signals for each FET included in the FET bridge 1030 based on the adjusted Hall signal from the variable delay circuit 1025 and the PWM code from the calculation unit 1021. Depending on the calculation result of the calculation unit 1021, the motor 105 may be powered or regeneratively braked. Note that basic operations such as motor drive are described in the pamphlet of International Publication No. 2012 / 086459 and the like, and are not a main part of this embodiment, so a description thereof will be omitted here.

[0030] 3 shows an example of the functional block configuration related to the push control unit 3000 that performs control in the push state in the calculation unit 1021. The push control unit 3000 has a mode determination unit 3100, a second control unit 3200, and a third control unit 3300. In addition to the push control unit 3000, there is also provided a first control unit 4000 that performs normal control when the user is riding the power-assisted bicycle 1, rather than when the bicycle is being pushed by hand.

[0031] The mode determination unit 3100 determines whether the current mode is the first, second, or third mode based on the state input from the state input unit 1023 and whether the hand-push assist button on the operation panel 106 is on or off. More specifically, if the bicycle is not being pushed by hand, the mode determination unit 3100 determines that the current mode is the first mode, in which the user is riding the power-assisted bicycle 1 and controls the motor 105 as usual. When the mode determination unit 3100 determines that the current mode is the first mode, it causes the first control unit 4000 to perform control. The first control unit 4000 controls the motor 105 to perform power running or regenerative braking based on the pedal rotation input from the pedal rotation input unit 1022, the torque input from the torque input unit 1027, the motor rotation input from the motor rotation input unit 1024, etc.

[0032] Furthermore, when the bicycle is being pushed by hand and a push assist request has been input using the push assist button, the mode is determined to be the second mode, which mainly controls the motor 105 to power according to the speed of the electrically assisted bicycle 1. When the mode determination unit 3100 determines that the bicycle is in the second mode, it causes the second control unit 3200 to perform control.

[0033] For example, the second control unit 3200 controls the positive output torque to decrease as the vehicle speed increases until the vehicle speed reaches a first positive threshold value (for example, approximately a normal walking speed). The positive output torque is a torque that rotates the motor 105 to move the power-assisted bicycle 1 forward, and is generated mainly by powering the motor 105 in the forward direction (positive direction). However, when the power-assisted bicycle 1 is moving backward, the motor 105 may be regeneratively braked in the backward direction (negative direction). On the other hand, the negative output torque is a torque that rotates the motor 105 to move the power-assisted bicycle 1 backward, and is generated mainly by regeneratively braking the motor 105 in the forward direction (positive direction). However, in some cases, the motor 105 may be powered in the backward direction (negative direction).

[0034] On the other hand, because deviation from the user's walking speed places a burden on the user, the second control unit 3200 controls the motor 105, for example, when the vehicle speed exceeds a positive first threshold value, so that the negative output torque increases as the vehicle speed increases. In this way, the positive first threshold value becomes the target speed. Also, for example, if the push assist button is pressed to move the power-assisted bicycle 1 forward, but the bicycle 1 moves backward due to a steep slope, the vehicle speed will indicate a negative value. In this way, even if the vehicle speed is a negative value, if the user is trying to move the power-assisted bicycle 1 forward, the second control unit 3200 controls the motor 105 so that the positive torque increases as the vehicle speed decreases.

[0035] FIG. 4 illustrates an example of a control mode in the second mode. FIG. 4 shows a plane in which the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1 and the vertical axis represents the output torque. A positive value for the vehicle speed indicates forward movement, while a negative value indicates reverse movement. A positive value for the output torque indicates assistance for forward movement or braking for reverse movement, while a negative value indicates braking for forward movement. In the first quadrant of this plane, both the vehicle speed and the output torque are positive. This typically indicates a state in which the user is manually pushing the electrically assisted bicycle 1 on an uphill or flat road, as shown in FIG. 4. The positive output torque assists the user, reducing the user's load. However, as shown in the fourth quadrant of FIG. 4, if the user continues to press the hand-push assist button even when going downhill, the vehicle speed may increase and exceed the positive first threshold. To avoid this situation, a negative output torque is generated to slow down the electrically assisted bicycle 1. As shown schematically in the second quadrant of Figure 4, even if the push assist button is continuously pressed on a steep uphill slope and the power-assisted bicycle 1 is moving backward due to gravity, i.e., the vehicle speed is showing a negative value, by generating a positive output torque, the user's burden can be reduced and the bicycle can move forward as intended.

[0036] Furthermore, when the bicycle is being pushed by hand and no push assist command has been input using the push assist button, the mode is determined to be the third mode, which mainly performs control to generate braking force (for example, regenerative braking force) according to the speed of the power-assisted bicycle 1. When the mode determination unit 3100 determines that the bicycle is in the third mode, it causes the third control unit 3300 to perform control.

[0037] For example, if the vehicle speed is positive and less than a second positive threshold (for example, a speed slightly faster than a normal walking speed), the third control unit 3300 performs control such that neither positive output torque nor negative output torque is output. This is because the user is not pressing the hand-push assist button, and therefore no assistance is provided at a normal walking speed, and the user does not feel any discomfort. On the other hand, if the vehicle speed is too fast, the user may feel uncomfortable or it may be a burden. Therefore, for example, when the vehicle speed exceeds the second positive threshold, the third control unit 3300 performs control such that the negative output torque increases as the vehicle speed increases, specifically, the regenerative braking force increases. In this way, the range less than the second positive threshold becomes the target speed range.

[0038] FIG. 5 shows an example of a control mode in the third mode. FIG. 5 also shows a plane in which the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1 and the vertical axis represents the output torque. In the third mode, as shown in FIG. 5, no control is performed in the first quadrant. Meanwhile, in the fourth quadrant, for example, when going downhill, the vehicle speed may increase and exceed the second positive threshold. To avoid this situation, which would be a burden on the user, and to decelerate the electrically assisted bicycle 1, the third control unit 3300 controls the vehicle speed to increase the negative output torque as the vehicle speed increases. Specifically, the third control unit 3300 controls the vehicle speed to increase the regenerative braking force. In some cases, as shown schematically in the second quadrant of FIG. 5, even when the electrically assisted bicycle 1 is moving backward due to gravity on a steep uphill slope, i.e., when the vehicle speed is negative, a positive output torque may be generated to reduce the user's burden and allow the bicycle to move forward as intended.

[0039] Next, the processing contents of the mode determination unit 3100 in this embodiment will be described with reference to Fig. 6. Note that steps S1 to S11 are executed at every predetermined control cycle.

[0040] First, the mode determination unit 3100 determines whether the power-assisted bicycle 1 is in a push-by state based on the state input from the state input unit 1023 (FIG. 6: step S1). That is, when the state input unit 1023 receives a signal from the riding prevention mechanism 108 indicating that the power-assisted bicycle 1 is in an initial state, the state input unit 1023 outputs a state input indicating that the power-assisted bicycle 1 is not in a push-by state to the mode determination unit 3100. When the mode determination unit 3100 determines that the power-assisted bicycle 1 is not in a push-by state, it determines that the mode is the first mode and causes the first control unit 4000 to perform processing for the first mode (step S3). The process then proceeds to step S11.

[0041] On the other hand, if the mode determination unit 3100 determines that the device is in the hand-pushing state, it determines whether the hand-pushing assist button has been pressed and a hand-pushing assist request has been made (step S5). If a hand-pushing assist request has been made, the mode determination unit 3100 determines that the device is in the second mode and causes the second control unit 3200 to perform processing for the second mode (step S7). The process then proceeds to step S11.

[0042] On the other hand, if a manual push assist request has not been made, the mode determination unit 3100 determines that the third mode is selected, and causes the third control unit 3300 to perform the processing of the third mode (step S9).

[0043] Then, the hand-push control unit 3000 determines whether the process is to end due to a command to turn off the power from the operation panel 106 or the like (step S11). If the process is not to end, the process returns to step S1. On the other hand, if the process is to end due to a command to turn off the power or the like, the process ends at this stage.

[0044] In this manner, when the user is pushing the power-assisted bicycle 1 by hand, the burden on the user can be reduced by performing control according to the user's intentions and circumstances.

[0045] [Embodiment 2] In this embodiment, a first example of processing in the third mode will be specifically described.

[0046] In this embodiment, in the third mode, control is performed as shown in FIG. 7. In FIG. 7, the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1, and the vertical axis represents the output torque. As shown in FIG. 7, the output torque Tout is 0 until the vehicle speed reaches a positive threshold TH4 (e.g., 3 km). In other words, since the user has not requested hand-pushing assistance, no assistance is provided. However, since the vehicle speed is not so fast that deceleration is not required, the user continues to push the bicycle. However, if the vehicle speed exceeds the threshold TH4, the weight of the electrically assisted bicycle 1 may cause the vehicle speed to become too fast, for example, on a downhill slope, placing a heavy burden on the user. Therefore, control is performed so that the magnitude of the negative output torque (e.g., regenerative braking force) increases as the vehicle speed increases. In the example of FIG. 7, the slope of the line a is G (a negative value), and an appropriate value is set. Note that, although an example in which the negative output torque changes along the line a with a slope G is shown here, a predetermined curve or combination of lines may be defined instead of a straight line. This controls the vehicle speed to stay within the threshold value TH4, reducing the force with which the user pulls the power-assisted bicycle 1 on a downhill slope, for example, and easing the burden on the user.

[0047] As an example, if TH4=3km / h, G=-5, the wheel diameter of electrically assisted bicycle 1 is 26 inches, and the weight of electrically assisted bicycle 1 is 25kg, and electrically assisted bicycle 1 is released on a 10% downhill slope and no action is taken, the vehicle speed after 6 seconds will be approximately 20km / h, but with this control, the speed will be almost constant after about 4 seconds, and it is possible to automatically reduce the vehicle speed to around 6km / h.

[0048] Next, the processing contents of the third control unit 3300 and the like will be described with reference to Fig. 8. First, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH4 (step S21). If the current vehicle speed is less than the threshold value TH4, the third control unit 3300 sets the output torque Tout to 0 (step S23). Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S27). When a regenerative braking force is used as the braking force, the calculation unit 1021 controls the switching of the FET bridge 1030 to control the motor 105 to obtain the output torque Tout.

[0049] On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH4, the third control unit 3300 sets the output torque Tout as follows: Tout=G×(vehicle speed−TH4) (step S25). As described above, G is a negative value, and the output torque Tout itself is also a negative value. Then, the process proceeds to step S27.

[0050] In this way, the situation in which braking force should be applied can be appropriately detected according to the vehicle speed, thereby reducing the burden on the user.

[0051] In this embodiment, the vehicle speed is controlled toward a speed equal to or less than the threshold value TH4, that is, the target speed is set to a vehicle speed equal to or less than the threshold value TH4, and safety is ensured by appropriately setting the threshold value TH4.

[0052] Note that, when a control with a higher priority is performed, such as when the user applies a brake, the processing according to this embodiment is invalidated. This also applies to the other embodiments described below.

[0053] [Embodiment 3] In this embodiment, a second example of the processing in the third mode will be specifically described.

[0054] In this embodiment, control is performed in the third mode as shown in FIG. 9. In FIG. 9, the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1, and the vertical axis represents the output torque. The first and fourth quadrants are the same as those in FIG. 7 for the second embodiment. However, the slope of line b is G1 (a negative value). On the other hand, when the vehicle speed falls below a negative threshold TH5 (e.g., −2 km / h), control is performed so that the positive output torque increases as the absolute value of the vehicle speed increases. For example, on an uphill slope, the gradient may be steep or the weight of the electrically assisted bicycle 1 may be heavy, causing the bicycle to roll back down the slope even though the user wants to go up. In such cases, a burden on the user is placed on the user, so positive output torque is generated to prevent the bicycle from rolling back. In the example of FIG. 9, the slope of line c is G2 (a negative value), and an appropriate value is set. Note that, while an example is shown in which the negative output torque changes along line b with a slope of G1 and line c with a slope of G2, a predetermined curve or combination of lines may be used instead of a straight line. This controls the vehicle speed to stay within the threshold value TH5, reducing the burden on the user.

[0055] Next, the processing details of the third control unit 3300 and the like will be described with reference to Fig. 10. First, the third control unit 3300 determines whether the current vehicle speed is less than a negative threshold value TH5 (step S31). If the current vehicle speed is less than the threshold value TH5, the third control unit 3300 sets the output torque Tout to G2 x (vehicle speed - TH5) (step S33). Since G2 is a negative value and (vehicle speed - TH5) is also a negative value, the output torque Tout becomes a positive value. Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S35).

[0056] On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH5, the third control unit 3300 determines whether the current vehicle speed is less than a positive threshold value TH4 (step S37). If the current vehicle speed is less than the threshold value TH4, the third control unit 3300 sets the output torque Tout to 0 (step S39). Then, the process proceeds to step S35. On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH4, the third control unit 3300 sets the output torque Tout to G1 × (vehicle speed - TH4) (step S41). As described above, G1 is a negative value, and the output torque Tout itself is also a negative value. Then, the process proceeds to step S35.

[0057] In this way, it is possible to appropriately detect a situation in which a negative output torque should be generated in accordance with the vehicle speed and a situation in which a positive output torque should be generated in accordance with the vehicle speed, thereby reducing the burden on the user.

[0058] [Embodiment 4] For example, even when pulling the bicycle backward out of a bicycle parking space, depending on the setting of the negative threshold value TH5, a positive output torque may be generated in the third embodiment, and the power-assisted bicycle 1 may not be able to be reversed as intended by the user. Such reverse movements based on the user's intention typically end in a short period of time, so in this embodiment, control is exercised so that positive output torque is not output during short periods of reverse movement.

[0059] The content of this control will be specifically described using FIG. 11. In FIG. 11, the horizontal axis represents the elapsed time since the vehicle speed became less than a negative threshold value TH6 (e.g., −2 km / h), and the vertical axis represents the absolute value of the gain (gradient G2). As shown by the solid line f in FIG. 11, if the elapsed time since the vehicle speed became less than the negative threshold value TH6 (e.g., −2 km / h) is less than a threshold value TH10 (e.g., 3 seconds), the gain (gradient G2) is set to 0, thereby setting the output torque to zero. Then, when this elapsed time becomes equal to or greater than the threshold value TH10, the absolute value of the gain (gradient G2) is increased according to (elapsed time − TH10). When the elapsed time further increases and becomes equal to or greater than TH11 (e.g., 5 seconds), the absolute value of the gain (gradient G2) is maintained at a predetermined value |G2max|. The dotted line g will be described in the fifth embodiment.

[0060] In this way, the user's intended short-term backward movement is not impeded, and if the backward movement is not short-term, a positive output torque is output, thereby preventing the power-assisted bicycle 1 from moving backward.

[0061] If the threshold value TH6 is set to be smaller than the threshold value TH5, the counting of the elapsed time starts earlier, thereby improving safety.

[0062] 12, when (elapsed time - TH10) is equal to or less than 0, the output torque is 0 as shown by the dashed line e, and when (elapsed time - TH10) becomes a positive value, the absolute value of the slope G2 gradually increases, and the slope G2 is represented by the dotted line d. When (elapsed time - TH10) becomes equal to or greater than TH11, the slope G2 reaches G2max as shown by the solid line c.

[0063] Such control will be described with reference to FIGS. 13 and 14 as a processing flow of the third control unit 3300 and the like. First, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH6 (step S51). In the above example, the threshold value TH6 was the same as the threshold value TH5, but they do not have to be the same. If the current vehicle speed is equal to or greater than the threshold value TH6, the third control unit 3300 resets to 0 a counter that measures the elapsed time since the current vehicle speed became less than the negative threshold value TH6 (step S55). Then, the process proceeds to step S57.

[0064] On the other hand, if the current vehicle speed is less than the threshold value TH6, the third control unit 3300 counts up the counter value by one control cycle (step S53). Then, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH5 (step S57). If the current vehicle speed is equal to or greater than the threshold value TH5, the third control unit 3300 executes basic control processing, which is the same as the processing in the second embodiment (step S71). The basic control processing will be described with reference to FIG. 14. Then, the processing proceeds to step S69.

[0065] In the basic control process, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH4 (step S81). If the current vehicle speed is less than the threshold value TH4, the third control unit 3300 sets the output torque Tout to 0 (step S83). Then, the process returns to the original process.

[0066] On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH4, the third control section 3300 sets the output torque Tout=G1×(vehicle speed−TH4) (step S85), and then the process returns to the original process that called the process.

[0067] Returning to the explanation of the process in FIG. 13, if the vehicle speed is less than the threshold value TH5, the third control unit 3300 determines whether the counter value is less than the threshold value TH10 (step S59). If the counter value is less than the threshold value TH10, the third control unit 3300 sets G2=0 (step S61). Then, the third control unit 3300 sets output torque Tout=G2×(vehicle speed−TH5) (step S67). Furthermore, the calculation unit 1021 performs control to obtain output torque Tout (step S69).

[0068] Meanwhile, the third control unit 3300 determines whether the counter value is less than a threshold value TH11 (threshold value TH10<threshold value TH11) (step S63). If the counter value is less than the threshold value TH11, the third control unit 3300 sets G2 to a value corresponding to the counter value (step S65). Specifically, G2=G2max / (TH11-TH10)×(counter value-TH10). Then, the process proceeds to step S67. On the other hand, if the counter value is equal to or greater than the threshold value TH11, the third control unit 3300 sets G2 to G2max (step S66). Then, the process proceeds to step S67.

[0069] By performing the above-described processing, as explained with reference to FIG. 11, output torque is not generated for short periods of reverse movement, so that the intended reverse movement of the power-assisted bicycle 1 is not impeded.

[0070] [Embodiment 5] In the fourth embodiment, short-term reverse motion was considered to be in line with the user's intention, but if the vehicle speed during reverse motion is high, the vehicle will reverse significantly even in a short period of time, which will be a burden to the user. Therefore, it is preferable to suppress reverse motion by generating negative output torque for a shorter period of time rather than elapsed time TH10.

[0071] As shown by the dotted line g in FIG. 11, if the vehicle speed falls below a threshold value TH7 (e.g., -4 km / h < threshold value TH5) even for a moment, the absolute value of the gain (i.e., gradient G2) begins to increase when the elapsed time since the vehicle speed fell below a negative threshold value TH6 (e.g., -2 km / h) reaches or exceeds a threshold value TH12 (e.g., 1 second), which is shorter than threshold value TH10. Furthermore, if the elapsed time further increases and reaches or exceeds, for example, TH13 (e.g., 3 seconds), the absolute value of the gain (gradient G2) is maintained at a predetermined value |G2max'|. Furthermore, |G2max'| > |G2max|. In other words, a large positive output torque is applied over a short elapsed time, so that reverse motion is suddenly suppressed. This reduces the burden on the user caused by reverse motion.

[0072] Such control will be described with reference to Fig. 15 to Fig. 17 as a processing flow of the third control unit 3300 etc. First, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH6 (step S91). If the current vehicle speed is equal to or greater than the threshold value TH6, the third control unit 3300 resets to 0 a counter that measures the elapsed time since the current vehicle speed became less than the negative threshold value TH6 (step S95). Then, the process proceeds to step S97.

[0073] On the other hand, if the current vehicle speed is less than the threshold value TH6, the third control unit 3300 counts up the counter value by one control cycle (step S93). The third control unit 3300 also determines whether the current vehicle speed is equal to or greater than 0 (step S97). If the current vehicle speed is equal to or greater than 0, a flag indicating that a sudden reverse has occurred is set to OFF (step S99). In other words, once the vehicle speed falls below the threshold value TH7, processing is performed as if the vehicle speed were less than the threshold value TH7 until a safe state in which the electrically assisted bicycle 1 can move forward is detected. Then, processing proceeds to step S101. On the other hand, if the current vehicle speed is less than 0, processing proceeds to step S101.

[0074] Thereafter, the third control unit 3300 determines whether the current vehicle speed is less than a threshold value TH5 (step S101). If the current vehicle speed is equal to or greater than the threshold value TH5, the third control unit 3300 executes a basic control process that is the same as the process in the second embodiment (step S103). The basic control process is the same as that described with reference to FIG. 14. Then, the process proceeds to step S67 in FIG. 16 via a terminal B.

[0075] On the other hand, if the current vehicle speed is less than the threshold value TH5, the third control unit 3300 determines whether the current vehicle speed is less than the threshold value TH7 (step S105). If the current vehicle speed is less than the threshold value TH7, the third control unit 3300 sets a flag indicating that a sudden reverse movement has occurred to ON (step S107). Then, the processing shifts to the processing of FIG. 16 via a terminal A. On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH7, the processing shifts to the processing of FIG. 16 via a terminal A.

[0076] Shifting to the explanation of the processing in Fig. 16, the third control unit 3300 determines whether or not a flag indicating the occurrence of a sudden reverse movement is on (step S109). If the flag is on, the process proceeds to the processing in Fig. 17 via a terminal C. The feature of this embodiment is the processing in Fig. 17.

[0077] On the other hand, if the flag is off, steps S59 to S69 are executed. These processes are the same as those in Fig. 13 described in the fourth embodiment, and therefore a description of the processes will be omitted.

[0078] 17, the third control unit 3300 determines whether the counter value is less than the threshold value TH12 (step S111). If the counter value is less than the threshold value TH12, the third control unit 3300 sets G2 to 0 (step S113). Then, the process proceeds to step S67 in FIG. 16 via a terminal B. On the other hand, if the counter value is equal to or greater than the threshold value TH12, the third control unit 3300 determines whether the counter value is less than the threshold value TH13 (step S115). If the counter value is less than the threshold value TH13, the third control unit 3300 sets G2 to a value corresponding to G2max' and the counter value (step S117). Specifically, G2 is set as G2=G2max' / (TH13-TH12)×(counter value-TH12). Then, the process proceeds to step S67 in FIG. 16 via a terminal B. On the other hand, if the counter value is equal to or greater than the threshold value TH13, the third control unit 3300 sets G2max' to G2 (step S119). Then, the process proceeds to step S67 in FIG.

[0079] By performing such processing, it is possible to prevent a sudden reversal of the vehicle at an early stage, thereby improving safety.

[0080] The threshold value TH7=-4 km / h is set as an example of a speed at which the user feels burdened when reversing, but other values ​​may be used.

[0081] [Embodiment 6] In this embodiment, a first example of processing in the second mode will be specifically described.

[0082] In this embodiment, in the second mode, control as shown in FIG. 18 is performed. In FIG. 18, the horizontal axis represents the vehicle speed of the electric assist bicycle 1, and the vertical axis represents the output torque, showing a plane. Basically, if the vehicle speed is less than the positive threshold TH1 (for example, 5.5 km / h), control is performed in such a form that the positive output torque decreases as the vehicle speed increases, like the dotted line i with a negative slope G3 (= -Ta / TH1). Thereby, for example, when pushing the electric assist bicycle 1 uphill by hand, assistance is provided, reducing the burden on the user. And when the vehicle speed becomes equal to or higher than the positive threshold TH1, since the burden on the user increases even if the user requests hand-push assistance, control is performed such that the magnitude of the negative output torque increases in response to the increase in the vehicle speed so as to decelerate. By performing such control, control with the target speed set as the threshold TH1 is performed.

[0083] Note that the output torque when the vehicle speed is 0, that is, the intercept of the vertical axis, is Ta. By performing such control, control with the target speed set as the threshold TH1 is achieved.

[0084] Also, even when the vehicle speed is a negative value, a positive output torque is output to suppress the backward movement of the electric assist bicycle 1.

[0085] Note that the dotted line i is an example, and for example, even if the threshold TH1 is the same, control may be performed along a straight line such as the solid line j with a smaller slope G3. In this case, the intercept of the vertical axis is Ta' < Ta. Further, instead of just a straight line, as shown by the thick dotted line k in FIG. 18, it may be a broken line. In the case of the thick dotted line k, if the vehicle speed is less than the threshold TH1', the slope is the first negative slope and the intercept of the vertical axis is Ta", but if the vehicle speed is equal to or higher than the threshold TH1', the slope is the second negative slope. Thus, other functions with a plurality of straight lines or curves such that the output torque decreases from positive to negative as the vehicle speed increases may also be used.

[0086] It is also possible to control the assist section to have a gentler inclination, thereby reducing power consumption. The inclination may also be variable depending on the user's situation. For example, the electrically assisted bicycle 1 may be equipped with a function to detect or calculate the load, and when the load is heavy, the inclination may be made steeper, increasing the amount of assistance when the bicycle is being pushed by hand.

[0087] For example, if the push-assist button is pressed while the electrically assisted bicycle 1 is stopped, assistance will be provided suddenly, so the slew rate (for example, 10 Nm / h) that limits the time rate of change of the motor output torque is appropriately set, and adjustments are made so that the output torque corresponding to the bicycle speed is gradually output. This allows the electrically assisted bicycle 1 to be safely assisted when being pushed by hand.

[0088] Next, an example of the processing contents of the second control unit 3200 etc. will be described with reference to Fig. 19. Note that the case where the output torque changes along a straight line having a negative gradient G3 will be described.

[0089] The second control section 3200 sets the output torque Tout=G3×vehicle speed+Ta (step S201). In the case of the dotted line i in FIG. 18, G3=−Ta / TH1.

[0090] Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S203). When a regenerative braking force is used as the braking force, the calculation unit 1021 controls the motor 105 to obtain the output torque Tout by controlling the switching of the FET bridge 1030.

[0091] By performing this processing, appropriate assistance is provided according to the vehicle speed when going uphill, reducing the burden on the user. Also, if the vehicle speed exceeds the threshold TH1, it becomes a burden on the user, so the vehicle speed can be suppressed by applying braking force, allowing the user to push the electrically assisted bicycle 1 safely.

[0092] The threshold value TH1 = 5.5 km / h is set to a speed slightly faster than the typical walking speed when pushing the electrically assisted bicycle 1. If the threshold value TH1 were set to a faster value, such as 8 km / h, assistance would be provided even at speeds exceeding the typical walking speed, and the user could potentially be pulled by the electrically assisted bicycle 1. On the other hand, if the threshold value TH1 were set to a small value, such as 2 km / h, the user would hardly receive any benefit from the assistance. For this reason, a value such as 5.5 km / h is shown as an example of the threshold value TH1. However, the threshold value TH1 is not limited to 5.5 km / h, and other values ​​may be set.

[0093] [Embodiment 7] In this embodiment, the output torque is suppressed at low speeds below a threshold value TH2 (for example, 3 km / h), thereby enabling the power-assisted bicycle 1 to be pushed stably by hand at low speeds.

[0094] For example, control such as that shown in FIG. 20 is performed. FIG. 20 shows a plane in which the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1 and the vertical axis represents the output torque. If the vehicle speed is less than a positive threshold TH1 (e.g., 5.5 km / h) and greater than or equal to a threshold TH2, control is performed so that the positive output torque decreases as the vehicle speed increases, as shown by a line 1 having a negative slope G4 (=-Ta / (TH1-TH2)). If the vehicle speed is greater than or equal to the positive threshold TH1, control is performed so that the magnitude of the negative output torque increases as the vehicle speed increases, so as to decelerate. On the other hand, in this embodiment, if the vehicle speed is less than the threshold TH2, the output torque is set to a constant value Ta. As a result, for example, if a user pushing the electrically assisted bicycle 1 on flat ground slows down in an attempt to decelerate, the output torque will not increase but will remain constant once the vehicle speed becomes less than the threshold TH2. This means that assistance is provided in line with the user's walking speed without the output torque increasing contrary to the user's intention to decelerate.

[0095] If the threshold value TH1 is set to 5.5 km / h, then if the threshold value TH2 is set to a small value, such as 1 km / h, sufficient assistance may not be obtained when pushing the bicycle by hand, and if the threshold value TH2 is set to a large value, such as 5 km / h, the assistance may be too strong and the user may be pulled by the power-assisted bicycle 1. For these reasons, the threshold value TH2 is set to, for example, 3 km / h.

[0096] Next, an example of the processing contents of the second control unit 3200 when performing the control shown in FIG. 20 will be described with reference to FIG.

[0097] First, the second control unit 3200 determines whether the vehicle speed is less than the threshold value TH2 (step S211). If the vehicle speed is less than the threshold value TH2, the second control unit 3200 sets the output torque Tout to Ta (step S213). Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S217).

[0098] On the other hand, if the vehicle speed is equal to or greater than the threshold value TH2, the second control unit 3200 sets the output torque Tout as follows (step S215): G4 × vehicle speed + Ta × TH1 / (TH1-TH2). G4 = -Ta / (TH1-TH2). Ta × TH1 / (TH1-TH2) is the intercept of the straight line with the slope G4 with respect to the vertical axis. Then, the process proceeds to step S217.

[0099] By performing this process, the power-assisted bicycle 1 can be pushed stably by hand at low speeds.

[0100] [Embodiment 8] The threshold value TH2 in the seventh embodiment may be set to 0. This is to prevent excessive assistance when the power-assisted bicycle 1 moves backward.

[0101] For example, control such as that shown in Figure 22 is performed. Figure 22 shows a plane in which the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1 and the vertical axis represents the output torque. If the vehicle speed is less than a positive threshold TH1 (for example, 5.5 km / h) and greater than or equal to 0, control is performed such that the positive output torque decreases as the vehicle speed increases, as shown by a line m having a negative slope G3 (=-Ta / TH1). Furthermore, if the vehicle speed exceeds the positive threshold TH1, control is performed such that the magnitude of the negative output torque increases as the vehicle speed increases, so as to decelerate. On the other hand, in this embodiment, if the vehicle speed is less than 0, the output torque is set to a constant value Ta.

[0102] Next, an example of the processing contents of the second control unit 3200 when performing the control shown in FIG. 22 will be described with reference to FIG.

[0103] First, the second control unit 3200 determines whether the current vehicle speed is less than 0 (step S221). If the current vehicle speed is less than 0, the second control unit 3200 sets the output torque Tout to Ta (step S223). Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S227).

[0104] On the other hand, if the current vehicle speed is equal to or greater than 0, the second control section 3200 sets the output torque Tout as follows (step S225): G3 = -Ta / TH1. Then, the process proceeds to step S227.

[0105] By performing this process, the power-assisted bicycle 1 can be pushed stably by hand at low speeds.

[0106] [Embodiment 9] If the vehicle speed of the power-assisted bicycle 1 while reversing exceeds a certain level, there is a possibility that the bicycle may be reversing unintentionally, for example, on an uphill slope. To deal with this, for example, control such as that shown in Fig. 24 is performed.

[0107] 24 shows a plane in which the horizontal axis represents the vehicle speed of the electrically assisted bicycle 1 and the vertical axis represents the output torque. In the example of FIG. 24, when the vehicle speed is equal to or greater than a threshold value TH3 (for example, -2 km / h), the same operation as in the seventh embodiment is performed, but when the vehicle speed falls below the threshold value TH3, a positive output torque is output along a line n having a negative slope G5. In this way, if the vehicle is unintentionally backing up, the backing up can be suppressed, thereby improving safety.

[0108] Next, an example of the processing contents of the second control unit 3200 when performing the control shown in FIG. 24 will be described with reference to FIG.

[0109] First, the second control unit 3200 determines whether the current vehicle speed is less than the threshold value TH3 (step S231). If the current vehicle speed is less than the threshold value TH3, the second control unit 3200 sets the output torque Tout as follows (step S233): output torque Tout = G5 × vehicle speed + Ta - G5 × TH3. Then, the calculation unit 1021 performs control to obtain the output torque Tout (step S241).

[0110] On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH3, the second control unit 3200 determines whether the current vehicle speed is less than the threshold value TH2 (step S235). If the current vehicle speed is less than the threshold value TH2, the second control unit 3200 sets the output torque Tout to Ta (step S237). Then, the process proceeds to step S241.

[0111] On the other hand, if the current vehicle speed is equal to or greater than the threshold value TH2, the second control unit 3200 sets the output torque Tout as follows (step S239): G4 × vehicle speed + Ta × TH1 / (TH1-TH2). G4 = -Ta / (TH1-TH2). Ta × TH1 / (TH1-TH2) is the intercept of the straight line with the slope G4 with respect to the vertical axis. Then, the process proceeds to step S241.

[0112] By performing this process, even if the vehicle speed when moving backwards of the power-assisted bicycle 1 exceeds a certain level, the positive output torque is increased, making it possible to push the bicycle safely by hand.

[0113] [Embodiment 10] In the embodiments described so far, a hand push assist button is provided on the operation panel 106, and if the user requests hand push assist by pressing this hand push assist button, the second mode is determined to be in effect, and if the hand push assist button is not pressed, the third mode is determined to be in effect.

[0114] Alternatively, a manual braking button may be additionally provided so that the user can explicitly request manual braking. The manual braking button may be additionally provided on the operation panel 106. For example, as schematically shown in FIG. 26 , an operation panel 106 having a manual braking assist button 1061 is provided near the right handle, and a second operation panel 109 having a manual braking button 1091 is provided near the left handle. Instead of the second operation panel 109, only the manual braking button 1091 may be provided. In this way, pressing the manual braking button 1091 with a hand different from that used to press the manual braking assist button 1061 can prevent the user from pressing the wrong button. Furthermore, the operation panel 106 and the second operation panel 109 may be provided on opposite sides of the handle. Note that the manual braking assist button 1061 and the manual braking button 1091 may be operated differently. These switches are not limited to momentary switches, and may be alternate operation or toggle switches. Also, values ​​relating to the depression of the switches may be stored in memory 10211. Furthermore, the switches may be of different types to prevent the switch from being mistakenly depressed.

[0115] Next, Figure 27 shows an example of the functional block configuration related to the push control unit 3000b that performs control in the push state in the calculation unit 1021. The push control unit 3000b has a mode determination unit 3100b, a second control unit 3200, and a third control unit 3300. In addition to the push control unit 3000b, there is also provided a first control unit 4000 that performs normal control when the user is riding the power-assisted bicycle 1, rather than in the push state. Components with the same reference numbers as in Figure 3 perform the same processing, so their explanation will be omitted.

[0116] The mode determination unit 3100b determines whether the mode is the first mode, the second mode, or the third mode based on the state input from the state input unit 1023, whether the hand-push assist button 1061 on the operation panel 106 is on or off, and whether the hand-push brake button 1091 on the second operation panel 109 is on or off. More specifically, if the bicycle is not being pushed by hand, the mode determination unit 3100b determines that the mode is the first mode, in which the user is riding the power-assisted bicycle 1 and controls the motor 105 as usual. If the mode determination unit 3100b determines that the mode is the first mode, it causes the first control unit 4000 to perform control.

[0117] Furthermore, when the bicycle is being pushed by hand and a push assist request has been input using the push assist button 1061, the mode is determined to be the second mode, which mainly performs control to power the motor 105 in accordance with the speed of the electrically assisted bicycle 1. When the mode determination unit 3100b determines that the bicycle is in the second mode, it causes the second control unit 3200 to perform control.

[0118] Furthermore, when the bicycle is in a hand-pushed state and a hand-pushed braking request has been input using the hand-pushed braking button 1091, the mode is determined to be the third mode, which mainly performs control to generate braking force (for example, regenerative braking force) according to the speed of the power-assisted bicycle 1. When the mode determination unit 3100b determines that the bicycle is in the third mode, it causes the third control unit 3300 to perform control.

[0119] Next, the processing contents of the mode determination unit 3100b in this embodiment will be described with reference to Fig. 28. Note that steps S301 to S315 are executed at every predetermined control cycle.

[0120] First, the mode determination unit 3100b determines whether the power-assisted bicycle 1 is in a push-by state based on the state input from the state input unit 1023 (step S301). That is, when the state input unit 1023 receives a signal from the riding prevention mechanism 108 indicating that the riding prevention mechanism 108 is in its initial state, it outputs a state input indicating that the power-assisted bicycle 1 is not in a push-by state to the mode determination unit 3100b. When the state input unit 1023 receives a signal indicating that the riding prevention mechanism 108 is in the deployed state, it outputs a state input indicating that the power-assisted bicycle 1 is in a push-by state to the mode determination unit 3100b. When the mode determination unit 3100b determines that the power-assisted bicycle 1 is not in a push-by state, it determines that the mode is the first mode and causes the first control unit 4000 to perform processing for the first mode (step S303). The process then proceeds to step S315.

[0121] On the other hand, if the mode determination unit 3100b determines that the brake is being pressed manually, it determines whether the manual braking button 1091 has been pressed and a manual braking request has been made (step S305). If a manual braking request has been made, the mode determination unit 3100b determines that the brake is in the third mode and causes the third control unit 3300 to perform the third mode process (step S307). The process then proceeds to step S315. Note that the determination in step S305 is made before the determination in step S309 described below, and if both requests are made approximately simultaneously, braking (step S307) takes priority. This ensures safe operation.

[0122] On the other hand, if it is determined that there is no manual braking request, the mode determination unit 3100b determines whether the manual push assist button 1061 has been pressed to request manual push assist (step S309). If a manual push assist request has been made, the mode determination unit 3100b determines that the second mode is active and causes the second control unit 3200 to perform processing for the second mode (step S311). The process then proceeds to step S315.

[0123] On the other hand, if no request for manual push assistance has been made, the mode determination unit 3100b determines that the mode is the fourth mode, which is not any of the first to third modes, and sets it to no assistance or braking (step S313), and no processing of any of the first to third modes is performed.

[0124] Then, the hand-push control unit 3000 determines whether the process is to end due to a command to turn off the power from the operation panel 106 or the like (step S315). If the process is not to end, the process returns to step S301. On the other hand, if the process is to end due to a command to turn off the power or the like, the process ends at this stage.

[0125] In this way, the user can input a manual braking request separately from a manual assist request, and the assist and braking can be performed in a manner that meets the user's intentions.

[0126] [Embodiment 11] In the first to tenth embodiments, a hand-push assist request or a hand-push braking request is input using a hand-push assist button or a hand-push braking button, but it is also possible to determine whether a hand-push assist request or a hand-push braking request has been made using a sensor other than a button.

[0127] For example, as shown in FIG. 29, a stress sensor 111 is provided on a handle post 110 or the like, and the stress F inFrom this, it may be determined whether or not there is a request for hand-pushing assistance or a request for hand-pushing braking. For example, if stress in the forward direction is detected, it may be determined that there is a request for hand-pushing assistance, and if stress in the backward direction is detected, it may be determined that there is a request for hand-pushing braking.

[0128] The stress sensor 111 is just an example, and other sensors may be used, or may be installed in a location other than the handle post 110.

[0129] [Embodiment 12] In the embodiment described above, an example is shown in which braking force is generated by utilizing regeneration by the motor 105, but a mechanical braking force may also be generated.

[0130] Specifically, when the vehicle speed is equal to or greater than 0 and a negative output torque is to be generated, the output torque of motor 105 is set to 0, and a braking force of the same magnitude as the negative output torque is mechanically generated. Also, when the vehicle speed is less than 0 and a positive output torque is to be generated, the output torque of motor 105 may be set to 0, and a braking force of the same magnitude as the positive output torque may be mechanically generated.

[0131] An example of a configuration for such a case is shown in FIG. 30 and FIG.

[0132] Figure 30 is an external view showing an example of an electrically assisted bicycle, which is an example of an electrically assisted vehicle according to this embodiment. This electrically assisted bicycle 1b has the same components as the electrically assisted bicycle 1 shown in Figure 1, but also includes a brake actuator 131. The brake actuator 131 is connected to, for example, the brake wire of the rim brake on the front wheel, and adjusts the tension of the brake wire in response to instructions from the motor drive control device 102b. The brake actuator 131 is, for example, a stepping motor.

[0133] 30 shows an example of adjusting the tension of the brake wire connected to the rim brake of the front wheel, but the rim brake may be replaced with a disc brake, and the rim brake or disc brake of the rear wheel may also be controlled. Also, the brake actuator 131 may be integrated with the motor drive control device 102b, or if separated, may be located anywhere.

[0134] FIG. 31 shows a configuration related to a motor drive control device 102b according to this embodiment.

[0135] The basic configuration is the same as that of the motor drive control device 102 shown in FIG. 2, but the controller 1020 additionally includes a braking control unit 1031 that controls the brake actuator 131 in response to instructions from the calculation unit 1021.

[0136] When the braking control unit 1031 is instructed on the mechanical braking torque to be generated (for example, in the case of a negative output torque), it identifies a voltage waveform for realizing the brake wire displacement amount corresponding to the instructed braking torque based on a pre-prepared mapping between braking torque and brake wire displacement amount, and outputs the voltage waveform to the brake actuator 131. For example, it calculates and outputs a voltage waveform for realizing the difference between the brake wire displacement amount corresponding to the instructed braking torque and the current displacement amount. Then, the brake actuator 131 adjusts the brake wire displacement amount according to the input voltage waveform.

[0137] There are other implementation methods for realizing such mechanical braking torque, so the present invention is not limited to this.

[0138] Although the embodiments of the present invention have been described above, the present invention is not limited to these. For example, any technical feature in the above-described embodiments may be deleted depending on the purpose.

[0139] Furthermore, the functional block diagram described above is an example, and one functional block may be divided into multiple functional blocks, or multiple functional blocks may be integrated into one functional block. Regarding the processing flow, the order of steps may be changed or multiple steps may be executed in parallel, as long as the processing content remains the same.

[0140] The calculation unit 1021 may be implemented in part or in whole by a dedicated circuit, or may be configured to realize the above-described functions by executing a program prepared in advance.

[0141] Furthermore, in the embodiment described above, an example is shown in which, in accordance with laws and regulations, when the riding prevention mechanism 108 is in the deployed state and prevents the user from riding the power-assisted bicycle 1, the power-assisted bicycle 1 is recognized as being in a push state in which the power-assisted bicycle 1 is being pushed or pulled by hand and is capable of providing assistance, etc. However, in cases where there are no such legal restrictions, or in cases where the power-assisted bicycle is an electric vehicle that does not even need to be equipped with the riding prevention mechanism 108, such as a cart, wheelchair, or walking aid, the power-assisted bicycle may be recognized as being in a push state only when the power-assisted bicycle is being pushed or pulled by hand, or when it is determined explicitly or implicitly that assistance, etc., is permitted when the power-assisted bicycle is being pushed or pulled by hand.

[0142] In the case where the brake sensor 107 outputs the amount of operation of the brake lever, the brake actuator 131 may be operated based on the amount of operation of the brake lever obtained from the brake sensor 107.

[0143] The above-described embodiment can be summarized as follows.

[0144] The control device of the electrically power assisted vehicle in this embodiment switches to a first mode (e.g., a second mode in the embodiment) in which the motor of the electrically power assisted vehicle generates torque in a direction moving the electrically power assisted vehicle forward (e.g., a positive torque in the embodiment) in accordance with the vehicle speed of the electrically power assisted vehicle within a first range related to the vehicle speed of the electrically power assisted vehicle when it is determined that (A) the electrically power assisted vehicle is in a hand-pushed state and the user has requested assistance in the hand-pushed state (e.g., a hand-pushed assist request in the embodiment), and (B) switches to a second mode (e.g., a third mode in the embodiment) in which the braking operation is controlled in accordance with the vehicle speed of the electrically power assisted vehicle within a second range related to the vehicle speed of the electrically power assisted vehicle when it is determined that the user has not requested assistance in the hand-pushed state or has requested braking in the hand-pushed state.

[0145] By switching the control in this way, it is possible to reduce the burden on the user depending on the situation of the electrically assisted vehicle being pushed by hand and the user.

[0146] Furthermore, when it is determined that the electrically assisted vehicle is rideable and not being pushed by hand, the control unit described above may switch to a third mode (for example, the first mode in the first embodiment) in which the drive unit drives the motor based on human input to the electrically assisted vehicle (for example, pedal rotation).If the electrically assisted vehicle is an electrically assisted bicycle, it is appropriate to perform control in the third mode when the user is riding the electrically assisted bicycle.

[0147] The control unit described above may also determine whether the user has requested assistance in a hand-pushing state or whether the user has requested braking in a hand-pushing state based on the output of one or more operation switches (e.g., a hand-pushing assist button or a hand-pushing brake button) or a sensor (e.g., the stress sensor 111) that detects whether the user is pushing or pulling the electrically assisted vehicle by hand, in order to appropriately detect the user's intention.

[0148] Furthermore, the control unit described above may determine whether the electrically assisted vehicle is being pushed by hand based on whether a mechanism that prevents the user from riding the electrically assisted vehicle is functioning, in order to ensure that the user is not seated in the saddle in accordance with the law.

[0149] In the second mode described above, when the vehicle speed is equal to or greater than a first positive threshold value (e.g., threshold value TH4), control may be performed to generate a braking force according to the vehicle speed. Here, the braking force may be a braking force using a motor, such as a regenerative braking force, or may be a mechanical braking force. This is to ensure safety when the vehicle is being pushed by hand. For example, control such as that shown in FIG. 7 may be performed.

[0150] In the second mode described above, when the vehicle speed is equal to or less than a negative second threshold (e.g., threshold TH5), the motor may be controlled to generate torque in a direction that moves the electrically power assisted vehicle forward, or to generate mechanical braking force. This is to improve safety when reversing. For example, the control shown in FIG. 9 is performed.

[0151] Furthermore, in the second mode described above, when the time during which the vehicle speed is equal to or less than a negative third threshold (for example, threshold TH6) becomes equal to or greater than a first predetermined time (for example, threshold TH10), the motor may be controlled to generate torque in a direction that moves the electrically power assisted vehicle forward according to the vehicle speed and the time, or to generate mechanical braking force according to the vehicle speed and the time. When the vehicle is reversing, since reversing may be intentional if it is for a short period of time, the reversing vehicle speed is not slowed down depending on the time.

[0152] In the second mode described above, when the vehicle speed becomes equal to or less than a fourth threshold (for example, TH7) that is smaller than the third threshold, and the time period becomes equal to or greater than a second predetermined time period (for example, threshold TH12) that is shorter than the first predetermined time period, the motor may be controlled to generate torque in a direction that moves the electrically power assisted vehicle forward according to the vehicle speed and the time period, or to generate mechanical braking force according to the vehicle speed and the time period. If the vehicle speed when moving backward is high, the vehicle is quickly decelerated to avoid burden on the user.

[0153] Furthermore, the degree of increase in the torque or mechanical braking force generated by the motor relative to the vehicle speed may be set to be greater when the vehicle speed is equal to or less than the fourth threshold value than when the vehicle speed is not equal to or less than the fourth threshold value, in order to effectively prevent the vehicle from rolling backward.

[0154] Note that when the vehicle speed is below the first threshold and above the second threshold, the motor may not be driven or braked. In the second mode (the third mode in the embodiment), no assistance is explicitly requested, so no special operation is necessary within this range. However, if the battery has sufficient power, some assistance may be provided.

[0155] In the first mode described above, the drive unit may be controlled so that the driving force of the motor decreases as the vehicle speed increases, because even when assistance is required, excessively high speeds are undesirable.

[0156] Furthermore, in the first mode described above, when the vehicle speed is equal to or greater than a fifth threshold (for example, threshold TH1), control may be performed to generate a braking force. Even when assistance is required, when the vehicle speed is equal to or greater than the fifth threshold, the vehicle is decelerated to ensure safety. In other words, the fifth threshold is set as the target vehicle speed.

[0157] In the first mode described above, when the vehicle speed becomes a negative value, the motor may be controlled to generate torque in the direction that moves the electrically assisted vehicle forward, or to generate mechanical braking force. If assistance is requested but the electrically assisted vehicle is moving backward, an operation such as generating positive torque is carried out to ensure safety.

[0158] Furthermore, in the first mode described above, when the vehicle speed is below a sixth threshold (e.g., threshold TH2), the motor may be controlled to generate a constant torque in the direction that moves the electrically assisted vehicle forward, because providing strong assistance at low speeds would disrupt the user's walking pace.

[0159] In the first mode described above, there may be a third range of vehicle speed of the electrically assisted vehicle in which the motor generates a constant torque in the direction of moving the electrically assisted vehicle forward, or a fourth range of vehicle speed of the electrically assisted vehicle in which the torque generated by the motor in the direction of moving the electrically assisted vehicle forward increases as the vehicle speed decreases. Assistance is performed in various ways depending on the vehicle speed.

[0160] Furthermore, in the first mode described above, when the vehicle speed is less than a seventh threshold (e.g., threshold TH3) that is a value equal to or less than 0, the motor may be controlled to generate torque in the direction that moves the electrically assisted vehicle forward according to the vehicle speed, or to generate mechanical braking force according to the vehicle speed, in order to effectively prevent the vehicle from reversing too fast.

[0161] Such a configuration is not limited to the matters described in the embodiment, and may be implemented in other configurations that provide substantially the same effects. [Explanation of symbols]

[0162] 3000 Hand-push control unit 3100 Mode determination unit 3200 Second Control Section 3300 Third Control Section 4000 First Control Section

Claims

1. when it is determined that the electrically assisted vehicle is in a hand-pushed state and that the user has requested assistance in the hand-pushed state, switching to a first mode in which the motor of the electrically assisted vehicle generates torque in a direction that moves the electrically assisted vehicle forward in accordance with the vehicle speed of the electrically assisted vehicle within a first range related to the vehicle speed of the electrically assisted vehicle; When the electrically assisted vehicle is in a hand-pushed state and it is determined that the user has not requested assistance in the hand-pushed state or that the user has requested braking in the hand-pushed state, if the vehicle speed of the electrically assisted vehicle is equal to or greater than a positive first threshold, the mode is switched to a second mode in which a motor of the electrically assisted vehicle generates a torque corresponding to the vehicle speed of the electrically assisted vehicle in a direction that causes the electrically assisted vehicle to move backward, or a mechanical braking force corresponding to the vehicle speed of the electrically assisted vehicle. Control device for electrically assisted vehicles.

2. When it is determined that the electrically assisted vehicle can be ridden and that the electrically assisted vehicle is not being pushed by hand, the mode is switched to a third mode in which the motor is driven based on a human input to the electrically assisted vehicle. The control device according to claim 1 .

3. Whether or not the user has requested assistance in the hand-pushing state, or whether or not the user has requested braking in the hand-pushing state, is determined based on the output of an operation switch or a sensor that detects whether the user is pushing or pulling the electrically assisted vehicle by hand. The control device according to claim 1 or 2.

4. Whether the electrically assisted vehicle is being pushed by hand is determined based on whether a mechanism that prevents the user from getting on the electrically assisted vehicle is functioning. The control device according to any one of claims 1 to 3.

5. When the electrically assisted vehicle is in a hand-pushed state and it is determined that the user has not requested assistance in the hand-pushed state or that the user has requested braking in the hand-pushed state, if the vehicle speed of the electrically assisted vehicle is equal to or less than a negative second threshold, the motor is controlled to generate torque in a direction that moves the electrically assisted vehicle forward or to generate mechanical braking force. The control device according to any one of claims 1 to 4.

6. When the electrically assisted vehicle is in a hand-pushed state and it is determined that the user has not requested assistance in the hand-pushed state or that the user has requested braking in the hand-pushed state, if the time during which the vehicle speed is equal to or less than a negative third threshold is equal to or greater than a first predetermined time, the motor is controlled to generate torque in a direction that moves the electrically assisted vehicle forward according to the vehicle speed and the time, or to generate mechanical braking force according to the vehicle speed and the time. The control device according to any one of claims 1 to 4.

7. When the electrically assisted vehicle is in a hand-pushed state and it is determined that the user has not requested assistance in the hand-pushed state or that the user has requested braking in the hand-pushed state, if the vehicle speed becomes equal to or less than a fourth threshold value that is smaller than the third threshold value and the time period becomes equal to or greater than a second predetermined time period that is shorter than the first predetermined time period, the motor is controlled to generate torque in a direction that moves the electrically assisted vehicle forward according to the vehicle speed and the time period, or to generate a mechanical braking force according to the vehicle speed and the time period. The control device according to claim 6.

8. The degree of increase in the torque generated by the motor or the mechanical braking force relative to the vehicle speed is greater when the vehicle speed is equal to or less than the fourth threshold value than when the vehicle speed does not become equal to or less than the fourth threshold value. The control device according to claim 7.

9. When the vehicle speed is less than the first threshold value and exceeds the second threshold value, the motor is not driven and the braking operation is not performed. The control device according to claim 5.

10. In the first mode, The driving force of the motor is controlled to decrease in accordance with an increase in the vehicle speed. The control device according to any one of claims 1 to 9.

11. In the first mode, When the vehicle speed is equal to or greater than a fifth threshold, control is performed to generate a braking force. The control device according to claim 10.

12. In the first mode, When the vehicle speed becomes a negative value, the motor is controlled to generate torque in a direction to move the electrically assisted vehicle forward or to generate mechanical braking force. The control device according to claim 10.

13. In the first mode, When the vehicle speed is less than a sixth threshold, the motor is controlled to generate a constant torque in a direction that moves the electrically assisted vehicle forward. The control device according to claim 10.

14. In the first mode, There is a second range of vehicle speed of the electrically power assisted vehicle in which the motor generates a constant torque in a direction to move the electrically power assisted vehicle forward, or a third range of vehicle speed of the electrically power assisted vehicle in which the torque generated by the motor in a direction to move the electrically power assisted vehicle forward increases as the vehicle speed decreases. The control device according to claim 10.

15. In the first mode, When the vehicle speed is less than a seventh threshold value that is equal to or less than 0, the motor is controlled to generate torque in a direction that moves the electrically assisted vehicle forward according to the vehicle speed, or to generate a mechanical braking force according to the vehicle speed. The control device according to claim 10.

16. An electrically assisted vehicle comprising the control device according to any one of claims 1 to 15.

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