Control device for human-powered vehicles

Abstract

The present invention provides a control device that can suppress wheel slippage in walk mode. [Solution] A control device for a human-powered vehicle, comprising a motor that provides assist force to the human-powered vehicle and a control unit configured to control a transmission, wherein in a walk mode in which the motor can be driven in response to the operation of an operating unit that can be operated by the user, the control unit controls the transmission such that the ratio of the total number of teeth of the rear sprocket of the human-powered vehicle to the total number of teeth of the front sprocket of the human-powered vehicle becomes smaller when the wheel slip-related conditions satisfy predetermined conditions.

Description

Technical Field

[0001] This disclosure relates to the technology of a control device for a human-powered vehicle.

Background Art

[0002] Conventionally, a control device for a human-powered vehicle is known. For example, Patent Document 1 discloses a technology of a control device that applies an assist force to a human-powered vehicle by controlling a motor. The control device includes a walk mode capable of driving the motor in response to an operation of an operation unit that can be operated by a user. The walk mode is used when the user pushes and walks with the human-powered vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A technology capable of suppressing wheel slip in the walk mode is desired.

[0005] One object of this disclosure is to provide a control device capable of suppressing wheel slip in the walk mode.

Means for Solving the Problems

[0006] A control device according to a first aspect of this disclosure is a control device for a human-powered vehicle, including a motor that applies an assist force to the human-powered vehicle and a control unit configured to control a transmission. The control unit controls the transmission so that the ratio of the total number of teeth of the rear sprocket of the human-powered vehicle to the total number of teeth of the front sprocket of the human-powered vehicle becomes smaller when wheel slip related conditions satisfy a predetermined condition in a walk mode in which the motor can be driven in response to an operation of an operation unit that can be operated by a user. According to the control device on the first side, wheel slippage can be suppressed in walk mode.

[0007] In the control device of the second side relating to the first side, the control unit controls the transmission so that, in walk mode, when the wheel slip-related conditions satisfy predetermined conditions, the chain moves from the gear currently engaged to the top gear on at least one of the front sprocket and the rear sprocket. According to the control device on the second side, wheel slippage can be suppressed in walk mode.

[0008] In the control device of the first or third side according to the second side, the predetermined condition is satisfied when at least one of the conditions relating to the posture of the human-powered vehicle and the conditions relating to the driving state is satisfied. According to the control device on the third side, the transmission can be controlled according to at least one of the conditions relating to the posture of the human-powered vehicle and the conditions relating to the driving state.

[0009] In the control device on the fourth side following the third side, the attitude includes the pitch angle of the human-powered vehicle. According to the control device on the fourth side, the transmission can be controlled according to the pitch angle.

[0010] In a control device of the fifth side relating to the third or fourth side, the driving state includes at least one of the inclination angle of the road surface on which the human-powered vehicle is traveling, and the condition of the road surface. According to the control device on the fifth side, the transmission can be controlled according to the angle of inclination of the road surface and at least one of the road surface conditions.

[0011] In a control device of a sixth side that conforms to any one of the first to fifth sides, the control unit modifies the output of the motor in walk mode according to at least one of the vehicle speed of the human-powered vehicle, the wheel speed, and the acceleration. According to the control device on the sixth side, the motor output can be changed according to at least one of the vehicle speed, wheel speed, and acceleration.

[0012] In the control device of the seventh side according to the sixth side, the control unit modifies the motor output in walk mode in accordance with a comparison of at least two of the vehicle speed, wheel speed, and acceleration of the human-powered vehicle. According to the control device on the seventh side, the motor output can be changed in accordance with a comparison of at least two of the following: vehicle speed, wheel speed, and acceleration.

[0013] In a control device of the eighth side that follows any one of the first to seventh sides, the control unit, when the wheel slip-related conditions in walk mode satisfy predetermined conditions, first reduces the output of the motor and then controls the transmission so that the ratio of the total number of teeth of the rear sprocket of the human-powered vehicle to the total number of teeth of the front sprocket of the human-powered vehicle becomes smaller. According to the control device on the eighth side, the transmission can be controlled after the motor output has been reduced. [Effects of the Invention]

[0014] According to the control device of this disclosure, wheel slippage can be suppressed in walk mode. [Brief explanation of the drawing]

[0015] [Figure 1] A side view showing a human-powered vehicle equipped with a control device according to the first embodiment. [Figure 2] A block diagram showing an example of the electrical configuration of a human-powered vehicle equipped with a control device. [Figure 3] A flowchart showing the control flow in the first embodiment. [Figure 4] A schematic diagram showing the state of the chain before the transmission is controlled in the first embodiment. [Figure 5] A schematic diagram showing the state of the chain after the transmission has been controlled in the first embodiment. [Figure 6] A flowchart showing the control flow in the second embodiment. [Figure 7] A flowchart showing the control flow in the third embodiment. [Figure 8] A flowchart showing the control flow in the fourth embodiment.

Mode for Carrying Out the Invention

[0016] (First Embodiment) A human-powered vehicle 1 including a control device 21 for a human-powered vehicle according to the first embodiment will be described. FIGS. 1 to 5 are used for the description of the control device 21 according to the first embodiment.

[0017] The human-powered vehicle 1 is a vehicle having at least one wheel 15 and capable of being driven by at least human driving force. The human-powered vehicle 1 includes various types of bicycles such as, for example, mountain bikes, road bikes, city bikes, cargo bikes, hand bikes, and recumbent bikes. The number of wheels 15 that the human-powered vehicle 1 has is not limited. The human-powered vehicle 1 includes, for example, a unicycle and a vehicle having two or more wheels 15. The human-powered vehicle 1 is not limited to a vehicle that can be driven only by human driving force. The human-powered vehicle 1 includes an E-bike that uses the driving force of an electric motor in addition to human driving force for propulsion. The E-bike includes an electric assist bicycle whose propulsion is assisted by an electric motor. Hereinafter, in the embodiments, the human-powered vehicle 1 will be described as a bicycle.

[0018] In this specification, the terms "front", "rear", "forward", "backward", "left", "right", "sideways", "upward", and "downward" indicating the following directions, and any other similar direction-indicating terms refer to those directions determined based on a rider facing the handlebar 13 at the reference position of the human-powered vehicle l (for example, on the saddle or seat 12).

[0019] As shown in Figures 1 and 2, the human-powered vehicle 1 comprises a crank 10, a frame 11, a seat 12, handlebars 13, a front fork 14, wheels 15, a drive mechanism 16, a transmission 17, a battery 18, a drive unit 19, and a control system 20. The crank 10 shown in Figure 1 includes a crank shaft 10a that is rotatable relative to the frame 11, and a pair of crank arms 10b provided at both axial ends of the crank shaft 10a. Pedals 10c are connected to each of the pair of crank arms 10b.

[0020] A seat 12 is provided on the frame 11 via a seat post 12a. The frame 11 rotatably supports the handlebars 13 and the front fork 14. The handlebars 13 are configured to be gripped by the rider. As the handlebars 13 rotate relative to the frame 11, the front fork 14 rotates, changing the direction of travel of the human-powered vehicle 1.

[0021] The wheel 15 includes a front wheel 15a and a rear wheel 15b. The front wheel 15a is rotatably mounted on the front fork 14. The rear wheel 15b is rotatably mounted on the frame 11. The drive mechanism 16 connects the crank 10 and the rear wheel 15b to each other. The drive mechanism 16 includes a first rotating body 16a, a second rotating body 16b, and a power transmission unit 16c.

[0022] The first rotating body 16a includes, for example, one front sprocket 16d. The one front sprocket 16d is configured to rotate integrally with the crankshaft 10a when the crankshaft 10a rotates in a first rotational direction. The first rotational direction is the direction in which the rotation of the one front sprocket 16d is transmitted to the rear wheel 15b, causing the rear wheel 15b to rotate forward.

[0023] As the crankshaft 10a rotates in a first rotational direction, one front sprocket 16d rotates, and the human-powered driving force is transmitted to the rear wheel 15b. The human-powered vehicle 1 moves forward as the human-powered driving force is transmitted to the rear wheel 15b. The one front sprocket 16d may be connected to the crankshaft 10a via a one-way clutch that allows the crankshaft 10a and the one front sprocket 16d to rotate together when the crankshaft 10a rotates in a first rotational direction, and prohibits the one-way rotation of the crankshaft 10a and the one front sprocket 16d when the crankshaft 10a rotates in a second rotational direction opposite to the first rotational direction.

[0024] The second rotating body 16b is configured to output human-powered driving force to the rear wheel 15b. The second rotating body 16b includes, for example, multiple rear sprockets 16e. The second rotating body 16b may include one rear sprocket 16e. Multiple rear sprockets 16e are connected to the rear wheel 15b.

[0025] The total number of teeth on each of the multiple rear sprockets 16e are different. The multiple rear sprockets 16e are stacked, for example, in order of total number of teeth. Among the multiple rear sprockets 16e, the rear sprocket 16e with a larger total number of teeth is positioned closer to the frame 11 than the rear sprocket 16e with a smaller total number of teeth.

[0026] The drive force transmission unit 16c transmits the rotational force of the first rotating body 16a to the second rotating body 16b. The drive force transmission unit 16c includes a chain 16f. The configuration of the drive mechanism 16 is not limited to this embodiment. The drive mechanism 16 may connect the crank 10 and the rear wheel 15b to each other, for example, by pulleys and a belt.

[0027] The transmission 17 includes at least one of an external gearbox and an internal gearbox. In this embodiment, the transmission 17 includes an external gearbox. The external gearbox is configured to change the ratio of the total number of teeth of the rear sprocket 16e of the human-powered vehicle 1 to the total number of teeth of the front sprocket 16d of the human-powered vehicle 1. In this specification, the ratio of the total number of teeth of the rear sprocket 16e to the total number of teeth of the front sprocket 16d may be referred to as the tooth ratio. The tooth ratio is calculated by dividing the total number of teeth of the rear sprocket 16e by the total number of teeth of the front sprocket 16d.

[0028] If the derailleur 17 includes an external derailleur, the external derailleur includes at least one of a front derailleur and a rear derailleur 17a. In this embodiment, the external derailleur includes a rear derailleur 17a. The rear derailleur 17a is configured to allow the chain 16f to be re-entangled between a plurality of rear sprockets 16e when a gear shifting device provided on the handlebar 13 is operated by the rider.

[0029] For example, the rear derailleur 17a increases the tooth ratio by switching the chain 16f to a rear sprocket 16e with a larger total number of teeth than the rear sprocket 16e with which the chain 16f is currently engaged. In this specification, gears that can increase the tooth ratio may be described as low gears.

[0030] For example, the rear derailleur 17a reduces the tooth ratio by switching the chain 16f to a rear sprocket 16e with fewer teeth than the rear sprocket 16e with which the chain 16f is currently engaged. In this specification, a gear that can reduce the tooth ratio may be described as the top gear.

[0031] The method by which the gear shifter 17 changes the tooth ratio is not limited to this embodiment. For example, a plurality of front sprockets 16d with different total tooth counts may be provided on the human-powered vehicle 1, and the tooth ratio may be changed by at least one of the front derailleur and the rear derailleur 17a. The plurality of front sprockets 16d may be stacked in order of total tooth count, for example. Among the plurality of front sprockets 16d, the front sprocket 16d with a smaller total tooth count is positioned closer to the frame 11 than the front sprocket 16d with a larger total tooth count.

[0032] For example, the front derailleur can reduce the tooth ratio by switching the chain 16f to a front sprocket 16d with a larger total number of teeth than the front sprocket 16d to which the chain 16f is currently engaged. For example, the front derailleur can increase the tooth ratio by switching the chain 16f to a front sprocket 16d with a smaller total number of teeth than the front sprocket 16d to which the chain 16f is currently engaged. If the gear shifter 17 can change the tooth ratio using the front derailleur, the human-powered vehicle 1 does not necessarily need to be equipped with a rear derailleur 17a.

[0033] The battery 18 supplies power to components mounted on the human-powered vehicle 1. These components include, for example, a drive unit 19. The battery 18 includes, for example, at least one non-rechargeable battery and a rechargeable battery. The rechargeable battery is configured to be rechargeable by power from an external power source. The battery 18 is provided on the frame 11. In this embodiment, at least a portion of the battery 18 is located in the internal space of the frame 11.

[0034] The drive unit 19 can provide assist force to the human-powered vehicle 1 in accordance with the human-powered driving force. The drive unit 19 includes a motor 19a. The motor 19a is configured to be powered by electricity from the battery 18. The motor 19a is configured to transmit driving force to the power transmission path of the human-powered driving force from the pedal 10c to the rear wheel 15b, or to the front wheel 15a. In this embodiment, the motor 19a is configured to transmit driving force to the power transmission path of the human-powered driving force. The motor 19a may also be configured to transmit driving force to the power transmission path of the human-powered driving force via a reduction gear.

[0035] The control system 20 shown in Figure 2 comprises a control device 21 and a detection unit 22. The control device 21 is a control device 21 for a human-powered vehicle and comprises a control unit 21b configured to control a motor 19a that provides assist force to the human-powered vehicle 1 and a transmission 17. In this embodiment, the control device 21 further comprises a storage unit 21a.

[0036] The storage unit 21a is configured to store a control program and information used in control processing. The storage unit 21a includes, for example, at least one of a non-volatile memory, a volatile memory, and a hard disk.

[0037] The control unit 21b is configured to perform control over the control system 20. The control unit 21b includes an arithmetic processing unit that executes a predetermined control program. The arithmetic processing unit includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 21b may include one or more microcomputers. The control unit 21b further includes an inverter circuit connected to the motor 19a.

[0038] The detection unit 22 is configured to detect various information related to the human-powered vehicle 1. The detection unit 22 is configured to communicate with the control unit 21b via an electrical cable or a wireless communication device. The detection unit 22 can output a signal to the control unit 21b according to the detection result. The detection unit 22 includes a stage detection unit 23, a vehicle speed detection unit 24, a wheel speed detection unit 25, a tilt detection unit 26, and an acceleration detection unit 27.

[0039] The gear detection unit 23 is configured to detect the current gear of the transmission 17. In this embodiment, the gear detection unit 23 is configured to detect the current gear of the rear derailleur 17a. If a front derailleur is provided on the human-powered vehicle 1, the gear detection unit 23 may be configured to detect the current gear of the rear derailleur 17a.

[0040] The vehicle speed detection unit 24 is configured to detect the vehicle speed of the human-powered vehicle 1. The vehicle speed detection unit 24 is configured to detect the vehicle speed of the human-powered vehicle 1 based on, for example, the rotational speed of the wheels 15 detected by the wheel speed detection unit 25. The vehicle speed detection unit 24 may detect the vehicle speed based on information other than the rotational speed of the wheels 15. The vehicle speed detection unit 24 may include, for example, a GPS receiver provided in the human-powered vehicle 1. The vehicle speed detection unit 24 may detect the vehicle speed based on the current position of the human-powered vehicle 1 detected by the GPS receiver.

[0041] The wheel speed detection unit 25 is configured to detect the rotational speed of the wheels 15. The wheel speed detection unit 25 is configured to detect, for example, the rotational speed of both the front wheel 15a and the rear wheel 15b. The wheel speed detection unit 25 can detect the rotational speed of the front wheel 15a by means of a magnetic sensor, for example, which is attached to the front fork 14 and detects the magnetism of a magnet provided on the front wheel 15a. The wheel speed detection unit 25 can detect the rotational speed of the rear wheel 15b by means of a magnetic sensor, for example, which is attached to the frame 11 and detects the magnetism of a magnet provided on the rear wheel 15b.

[0042] The inclination detection unit 26 is configured to detect the inclination state of the human-powered vehicle 1. The inclination state is information indicating the degree to which the human-powered vehicle 1 is inclined relative to the horizontal plane when the human-powered vehicle 1 is traveling. The inclination state includes, for example, at least one of the pitch angle of the human-powered vehicle 1 and the inclination angle of the road surface.

[0043] The pitch angle is the rotation angle around the pitch axis along the left-right direction of the human-powered vehicle 1. The tilt detection unit 26 may detect the pitch angle based on the angular velocity of the pitch angle. For example, the tilt detection unit 26 may detect the pitch angle by detecting the angular velocity of the pitch angle at predetermined time intervals and integrating the detected angular velocity.

[0044] The inclination detection unit 26 may detect the inclination angle of the road surface based on the current position of the human-powered vehicle 1. For example, the inclination detection unit 26 may detect the inclination angle of the road surface based on the current position of the human-powered vehicle 1 detected by the GPS receiver and gradient information included in the map information pre-stored in the storage unit 21a.

[0045] The acceleration detection unit 27 is configured to detect the acceleration of the human-powered vehicle 1 along the direction of travel. The acceleration sensor includes, for example, a 3-axis acceleration sensor or a 6-axis acceleration sensor.

[0046] The control unit 21b is configured to communicate with the transmission 17 and the motor 19a via an electrical cable or a wireless communication device. The control unit 21b is configured to control the transmission 17 by outputting a signal to the transmission 17. By controlling the transmission 17, the control unit 21b can change the gear ratio of the human-powered vehicle 1.

[0047] The control unit 21b is configured to control the motor 19a by outputting a signal to the motor 19a. When the motor 19a is driven by the control unit 21b, an assist force is applied to the human-powered vehicle 1. In this embodiment, the control unit 21b can control the motor 19a to apply an assist force to the human-powered vehicle 1 when the vehicle speed of the human-powered vehicle 1 is below a predetermined speed, based on the detection result of the vehicle speed detection unit 24. The predetermined speed is defined, for example, based on a specific law.

[0048] The control unit 21b is configured to communicate with the operation unit 30 via an electrical cable or a wireless communication device. The operation unit 30 is configured to be operated by the user with their hand or fingers. The operation unit 30 includes, for example, buttons. The operation unit 30 outputs a signal to the control unit 21b corresponding to the operation. The user can perform operations related to the assist force by operating the operation unit 30. For example, the user can perform operations related to the assist force by operating the operation unit 30. For example, the user can switch the power of the drive unit 19 on and off by operating the operation unit 30.

[0049] The control device 21 has multiple control modes. The control modes are modes for providing assist power to the human-powered vehicle 1. The control modes include a driving mode and a walking mode. The user can switch between the driving mode and the walking mode, or any of the multiple control modes, by operating the operating unit 30.

[0050] The riding mode is a mode in which the motor 19a is driven when the user pedals, thereby providing assist force to the human-powered vehicle 1. In the riding mode, the control unit 21b provides assist force, for example, in accordance with the human power driving force.

[0051] Walk mode is a mode in which assistance force can be applied to the human-powered vehicle 1 by driving the motor 19a when the user is not pedaling. Walk mode is used when the user is walking while pushing the human-powered vehicle 1. In walk mode, the control unit 21b applies assistance force to the human-powered vehicle 1 when predetermined assistance conditions are met. The assistance conditions are those that are met when the user is walking while pushing the human-powered vehicle 1. The assistance conditions are met, for example, when no human power is being input to the human-powered vehicle 1, the button on the operation unit 30 is pressed, and the vehicle speed of the human-powered vehicle 1 is below a predetermined upper limit. The predetermined upper limit is set, for example, to 6 kilometers per hour. In this specification, the upper limit of vehicle speed in walk mode is described as the upper speed limit. In walk mode, the control unit 21b can control the gear shifter 17.

[0052] In this embodiment, the control unit 21b controls the transmission 17 in a walk mode in which the motor 19a can be driven in response to the operation of the user-operable operation unit 30, such that the ratio of the total number of teeth of the rear sprocket 16e of the human-powered vehicle 1 to the total number of teeth of the front sprocket 16d of the human-powered vehicle 1 becomes smaller when the wheel slip-related conditions satisfy predetermined conditions. In this embodiment, the ratio of the total number of teeth of the rear sprocket 16e to the total number of teeth of the front sprocket 16d corresponds to the tooth ratio. When the human-powered vehicle 1 moves with a constant assist force, the smaller the tooth ratio, the higher the vehicle speed of the human-powered vehicle 1 becomes. When the human-powered vehicle 1 moves with a constant assist force, the smaller the tooth ratio, the lower the torque of the rear wheel 15b becomes.

[0053] The wheel slip-related conditions are conditions relating to the slip of the wheel 15. In this embodiment, the wheel slip-related conditions are conditions that cause the wheel 15 to slip in walk mode. The wheel slip-related conditions include at least one slip determination condition. The at least one slip determination condition is defined, for example, based on a parameter that increases or decreases either the frictional force between the wheel 15 and the road surface, or the torque of the wheel 15. The at least one slip determination condition is defined, for example, based on at least one of the tooth ratio, inclination state, and road surface condition. In this embodiment, the slip determination condition is defined based on the tooth ratio. The control unit 21b determines, for example, that the wheel slip-related conditions satisfy a predetermined condition when all of the at least one slip determination condition is met.

[0054] The relationship between wheel slip and the gear ratio is explained. For example, when a human-powered vehicle 1 moves with a constant assist force, increasing the gear ratio increases the torque of the wheel 15. As the torque of the wheel 15 increases, there is a possibility that the wheel 15 will slip in walk mode. In this embodiment, the slip determination condition is a condition that can determine whether the gear ratio is large enough to cause the wheel 15 to slip in walk mode. The slip determination condition is met, for example, when the gear ratio is greater than a predetermined threshold.

[0055] The relationship between wheel 15 slip and the inclination state is explained. The pitch angle of the human-powered vehicle 1 and the inclination angle of the road surface, which are included in the inclination state, increase as the gradient of the road surface increases, for example. As the gradient of the road surface increases, the load pressing the rear wheels 15b against the road surface decreases, so the frictional force between the wheels 15 and the road surface decreases. With the decrease in frictional force, the wheels 15 may slip in walk mode. The slip determination condition, which is defined based on the inclination state, may be a condition that can determine whether at least one of the pitch angle and the inclination angle of the road surface is large enough to cause the wheels 15 to slip in walk mode. The slip determination condition may be satisfied when at least one of the pitch angle and the inclination angle of the road surface is greater than or equal to a predetermined threshold.

[0056] The relationship between wheel 15 slippage and road surface conditions is explained. Road surface conditions are information indicating how slippery the road surface is. For example, road surface conditions include the degree of unevenness of the road surface, the amount of sand on the road surface, the amount of mud on the road surface, and the amount of snow on the road surface. For example, the less uneven the road surface is, the less frictional force there is between the wheel 15 and the road surface, and the more likely the wheel 15 is to slip. Slip determination conditions defined based on road surface conditions may be conditions that can determine, for example, whether the unevenness of the road surface is low enough that the wheel 15 may slip. Slip determination conditions may be satisfied, for example, when the unevenness of the road surface is less than a predetermined threshold.

[0057] For example, the more sand, mud, and snow on the road surface there is, the more likely the wheels 15 are to slip. The slip determination conditions, which are defined based on the road surface conditions, may be conditions that can determine whether at least one of the amounts of sand, mud, and snow on the road surface is large enough to cause the wheels 15 to slip. The slip determination conditions may be satisfied, for example, when at least one of the amounts of sand, mud, and snow on the road surface is above a predetermined threshold.

[0058] The slip detection conditions may be defined based on parameters other than the gear ratio, incline, and road surface conditions. For example, in walk mode, the brakes of the human-powered vehicle 1 may be operated. Since the wheels 15 may slip if they are locked by the operation of the brakes, the slip detection conditions may be conditions that can determine whether or not the wheels 15 are in a state where they are likely to lock. The slip detection conditions may be met, for example, when the brakes are operated.

[0059] An example of control performed by the control unit 21b is described. Figure 3 is used to describe an example of control performed by the control unit 21b. The control unit 21b starts a first control flow according to the flowchart shown in Figure 3 when predetermined conditions are met. In this embodiment, the control unit 21b starts the first control flow when the walk mode is selected by the operation of the operation unit 30. In the first control flow, the control unit 21b can control the tooth ratio so that the wheel 15 is less likely to slip.

[0060] As shown in Figure 3, in step S11, the control unit 21b controls the motor 19a in walk mode. When the assist conditions are met by controlling the motor 19a, an assist force is applied to the human-powered vehicle 1. By applying an assist force to the human-powered vehicle 1, the burden on the user when pushing the human-powered vehicle 1 while walking can be reduced. After performing the processing in step S11, the control unit 21b proceeds to step S12.

[0061] In step S12, the control unit 21b obtains the current number of steps from the step detection unit 23. If the obtained current number of steps is greater than or equal to a specific number of steps, the control unit 21b proceeds to step S15. If the obtained current number of steps is less than a specific number of steps, the control unit 21b proceeds to at least one of steps S13 and S14.

[0062] The specific gear in step S12 is set to one of the gears of the transmission 17, excluding at least the gear with the largest tooth ratio. The tooth ratio corresponding to the specific gear is small enough, for example, to prevent the wheels 15 from slipping in walk mode. In this embodiment, the specific gear is the gear with the smallest tooth ratio among the gears of the transmission 17.

[0063] The gear with the smallest tooth ratio is the gear in the transmission 17 that, when a constant assist force is applied to the human-powered vehicle 1, produces the smallest torque on the rear wheel 15b. In this embodiment, the gear with the smallest tooth ratio is the gear when the chain 16f is attached to the rear sprocket 16e with the smallest outer diameter among the multiple rear sprockets 16e.

[0064] In step S12, if the current gear is above a specific gear, it means that the 16f chain is engaged with at least one of the gears corresponding to that specific gear, or a gear higher than that specific gear. If the current gear is below a specific gear, it means that the 16f chain is engaged with a gear lower than the gear corresponding to that specific gear. When the current gear is below a specific gear, the tooth ratio is larger than when the current gear is above a specific gear, making the wheel 15 more prone to slipping.

[0065] In step S13, which is accessed if the current number of stages obtained in step S12 is less than a specific number of stages, the control unit 21b adjusts the assist output according to the current number of stages. For example, the control unit 21b reduces the assist output compared to when it transitioned to step S13. The assist output is a parameter that increases or decreases the assist force. The assist output includes at least one of the torque, rotational speed, and watts of the motor 19a. After processing in step S13, the control unit 21b proceeds to step S16.

[0066] In step S14, the control unit 21b controls the transmission 17 to change the gear position of the transmission 17 to a specified gear. The specified gear is a gear position with a tooth ratio that is one or more gears smaller than the gear position at the time of transitioning to step S14. For example, the specified gear may be a gear position with a tooth ratio that is only one gear smaller than the gear position at the time of transitioning to step S14. The specified gear does not necessarily have to be defined according to the gear position at the time of transitioning to step S14, as long as the tooth ratio is smaller than the gear position at the time of transitioning to step S14. For example, in this embodiment, since step S14 is performed when the tooth ratio is larger than a specific gear, the specified gear may be the same gear position as the specific gear.

[0067] The slip determination condition is met in step S12 of the first control flow if the current stage number is less than a specific stage. The control unit 21b determines that the wheel slip-related conditions meet predetermined conditions because the slip determination condition is met in step S12, and can proceed to step S14.

[0068] By performing step S14, the control unit 21b can control the derailleur 17 so that, in walk mode, when the wheel slip-related conditions satisfy predetermined conditions, the chain 16f moves from the gear it is currently on to the top gear on at least one of the front sprocket 16d and the rear sprocket 16e. In this embodiment, the control unit 21b can control the rear derailleur 17a so that, on the rear sprocket 16e, the chain 16f moves from the gear it is currently on to the top gear. After performing the processing in step S14, the control unit 21b proceeds to step S16.

[0069] The control content of the transmission 17 in step S14 may be changed according to the configuration of the transmission 17. For example, if the transmission 17 includes a front derailleur, the control unit 21b may control the front derailleur in step S14. For example, if the transmission 17 includes both a front derailleur and a rear derailleur 17a, the control unit 21b may control at least one of the front derailleur and the rear derailleur 17a in step S14.

[0070] When performing both step S13 and step S14, the control unit 21b may adjust the assist output according to the specified stage in step S14. The order in which steps S13 and S14 are performed is not particularly limited.

[0071] The control unit 21b may, for example, perform step S13 and step S14 simultaneously. The control unit 21b may, for example, perform one of step S13 and step S14, and then perform the other of step S13 and step S14. The control unit 21b may, for example, perform step S13, and then perform step S14.

[0072] By performing step S13 followed by step S14, the control unit 21b can, in walk mode, reduce the output of the motor 19a in advance and then control the transmission 17 so that the ratio of the total number of teeth of the rear sprocket 16e of the human-powered vehicle 1 to the total number of teeth of the front sprocket 16d of the human-powered vehicle 1 becomes smaller when the wheel slip-related conditions meet predetermined conditions. By reducing the output of the motor 19a in advance and then controlling the transmission 17, the control unit 21b can gradually reduce the torque of the rear wheel 15b. By gradually reducing the torque of the rear wheel 15b, the user is less likely to feel any discomfort in walk mode.

[0073] In step S15, which is performed if the current stage number obtained in step S12 is equal to or greater than a specific stage, the control unit 21b controls the motor 19a with a specified assist output. The specified assist output is the torque and rotational speed of the motor 19a that can satisfy the assist condition when the current stage number is equal to or greater than a specific stage.

[0074] In this embodiment, the specified assist output is set so that the assist output is maximized within the range where the assist conditions can be met. For example, the assist conditions include the condition that the vehicle speed of the human-powered vehicle 1 is less than or equal to the upper limit speed. When assist force is applied to the human-powered vehicle 1 in walk mode, the vehicle speed of the human-powered vehicle 1 changes according to, for example, the rotational speed of the motor 19a and the current gear. For example, if the gear is not shifted, the vehicle speed of the human-powered vehicle 1 increases as the rotational speed of the motor 19a increases. The specified assist output is set to, for example, the rotational speed of the motor 19a such that the human-powered vehicle 1 moves at the upper limit speed in the current gear. After processing in step S15, the control unit 21b proceeds to step S16.

[0075] In step S16, the control unit 21b terminates its operation in walk mode if it receives an instruction to terminate walk mode. For example, if the user selects a mode other than walk mode via the operation unit 30, the control unit 21b terminates the first control mode and ends its operation in walk mode. If there is no instruction to terminate walk mode, the control unit 21b proceeds to step S11.

[0076] The control unit 21b can appropriately control the gear shift of the transmission 17 in walk mode by executing the first control flow. Figure 4 schematically shows a state in which the chain 16f is engaged with a rear sprocket 16e that has a relatively large number of teeth and a large outer diameter. Figure 5 schematically shows a state in which the chain 16f is engaged with a rear sprocket 16e that has a relatively small number of teeth and a small outer diameter. The tooth ratio in the state shown in Figure 5 is smaller than the tooth ratio in the state shown in Figure 4.

[0077] The control unit 21b can reduce the gear ratio by executing the first control flow, switching from the state shown in Figure 4 to the state shown in Figure 5. By reducing the gear ratio, the torque acting on the rear wheel 15b can be reduced. By reducing the torque acting on the rear wheel 15b, slip of the wheel 15 in walk mode can be suppressed. The control unit 21b can reduce the torque acting on the rear wheel 15b by adjusting the assist output in step S13 shown in Figure 3, thereby lowering the assist output when the gear ratio is large.

[0078] The control unit 21b can make it less likely for a mismatch to occur between the speed of the human-powered vehicle 1 and the user's walking speed by adjusting the assist output in step S15. For example, if the user selects walk mode, it is assumed that they will push the human-powered vehicle 1 and walk at a speed corresponding to the upper limit speed.

[0079] In step S15, the control unit 21b can adjust the assist output so that the human-powered vehicle 1 moves at the upper speed limit. By adjusting the assist output, the speed of the human-powered vehicle 1 can be matched to the user's walking speed, making it less likely for a mismatch to occur between the speed of the human-powered vehicle 1 and the user's walking speed.

[0080] (Second Embodiment) The control device 21 of the second embodiment will be described. Figure 6 will be used to describe the control device 21 of the second embodiment. Components common to the first embodiment will be denoted by the same reference numerals as in the first embodiment, and redundant descriptions will be omitted.

[0081] In the second embodiment, the predetermined condition is met if at least one of the conditions relating to the posture of the human-powered vehicle 1 and the conditions relating to the driving state is met. The conditions relating to posture and the conditions relating to the driving state correspond to slip determination conditions. The posture of the human-powered vehicle 1 is information indicating the degree to which the human-powered vehicle 1 is inclined with respect to the horizontal plane. For example, the posture includes the pitch angle of the human-powered vehicle 1.

[0082] The driving state is information indicating the condition of the road surface on which the human-powered vehicle 1 is traveling. The driving state includes the inclination angle of the road surface on which the human-powered vehicle 1 is traveling, and at least one of the road surface conditions. In the second embodiment, the driving state includes the inclination angle of the road surface.

[0083] The pitch angle and the road surface inclination angle increase, for example, as the road surface gradient increases. When the road surface gradient increases, the wheels 15 may slip in walk mode. The conditions regarding posture may be met, for example, when the pitch angle is large enough that the wheels 15 may slip in walk mode. The conditions regarding driving conditions may be met, for example, when the road surface inclination angle is large enough that the wheels 15 may slip in walk mode.

[0084] An example of control performed by the control unit 21b is described. Figure 6 is used to describe an example of control performed by the control unit 21b. The control unit 21b starts a second control flow according to the flowchart shown in Figure 6, similar to the first embodiment. In the second control flow, the control unit 21b can control the tooth ratio so that the wheel 15 is less likely to slip, depending on at least one of the pitch angle and the road surface inclination angle.

[0085] As shown in Figure 6, in step S21, the control unit 21b controls the motor 19a in walk mode. After performing the processing in step S21, the control unit 21b proceeds to step S22.

[0086] In step S22, the control unit 21b proceeds to a different step depending on the inclination of the human-powered vehicle 1 with respect to the horizontal plane. For example, the control unit 21b obtains at least one of the pitch angle of the human-powered vehicle 1 and the inclination angle of the road surface from the inclination detection unit 26. If at least one of the obtained pitch angle and the inclination angle of the road surface is less than a predetermined threshold, the control unit 21b proceeds to step S27. If at least one of the obtained pitch angle and the inclination angle of the road surface is greater than or equal to a predetermined threshold, the control unit 21b proceeds to step S23.

[0087] In step S22, a predetermined threshold value is set to a value large enough that the wheels 15 are considered likely to slip. In step S22, the control unit 21b may convert at least one of the pitch angle and the road surface inclination angle to a unit different from angle and compare it with the predetermined threshold. For example, the control unit 21b may convert the road surface inclination angle to a gradient and compare it with the predetermined threshold. When the road surface inclination angle is converted to a gradient, for example, the predetermined threshold is set to +20 percent. In this specification, when the human-powered vehicle 1 is traveling uphill, the gradient is indicated by a positive value. The predetermined threshold may be set to a different magnitude than in this embodiment.

[0088] In step S23, the control unit 21b obtains the current stage number from the stage number detection unit 23. If the obtained current stage number is a specific stage, the control unit 21b proceeds to step S26. If the obtained current stage number is not a specific stage, the control unit 21b proceeds to at least one of step S24 and step S25.

[0089] The specific gear in step S23 is an intermediate gear among the gears of the transmission 17. The intermediate gear is selected from the gears of the transmission 17 other than the gear with the largest gear ratio and the gear with the smallest gear ratio. For example, if the transmission 17 has 12 gears and the gears are numbered from 1st to 12th in descending order of gear ratio, then gears 5 through 8 may be set as the intermediate gears.

[0090] In step S24, the control unit 21b adjusts the assist output according to the relationship between the current gear number obtained in step S23 and the specific gear number in step S23. For example, if the current gear number is less than the specific gear number, the torque acting on the wheels 15 is greater than when the current gear number is the specific gear number, making the wheels 15 more prone to slipping, so the control unit 21b lowers the assist output. For example, if the current gear number is greater than the specific gear number, the torque acting on the wheels 15 is smaller than when the current gear number is the specific gear number, making it more likely that the propulsion force of the human-powered vehicle 1 will be insufficient, so the control unit 21b increases the assist output.

[0091] In step S24, the range in which the assist output can be adjusted may be set in advance. By adjusting the assist output so that it does not exceed the adjustable range, the control unit 21b can prevent the assist output from increasing or decreasing excessively. After performing the processing in step S24, the control unit 21b proceeds to step S28.

[0092] In step S25, the control unit 21b changes the gear position of the transmission 17 to a specified gear. The specified gear in step S25 is either the same gear position as the specific gear position in step S23, or a gear position closer to the specific gear position than the current gear position.

[0093] The control unit 21b can reduce the gear ratio if the current gear number obtained in step S23 is less than the specified gear by changing the gear position of the transmission 17 to a specific gear. The control unit 21b can increase the gear ratio if the current gear number is greater than the specified gear by changing the gear position of the transmission 17 to a specific gear. After performing the processing in step S25, the control unit 21b proceeds to step S28.

[0094] If the control unit 21b performs both step S23 and step S24, it may adjust the assist output in step S23 according to the specified stage of step S24. The order in which steps S23 and S24 are performed is not particularly limited.

[0095] In step S26, which is performed if the current gear number obtained in step S23 is a specific gear, the control unit 21b controls the motor 19a at a specified assist output. The specified assist output in step S26 is the torque and rotational speed of the motor 19a that can satisfy the assist conditions when the current gear number is a specific gear and the human-powered vehicle 1 is moving uphill.

[0096] In the second embodiment, the specified assist output is set so that the assist output is as large as possible within the range that can satisfy the assist conditions. For example, the assist conditions include the condition that the vehicle speed of the human-powered vehicle 1 is less than or equal to the upper limit speed. For example, the vehicle speed of the human-powered vehicle 1 increases as the rotational speed of the motor 19a increases when the speed is not changed in walk mode. In step S26, the specified assist output is set to, for example, the rotational speed of the motor 19a such that the human-powered vehicle 1 moves at the upper limit speed at a specific stage. After processing in step S26, the control unit 21b proceeds to step S28.

[0097] In step S27, which is initiated if at least one of the pitch angle and the road surface inclination angle obtained in step S22 is less than a predetermined threshold, the control unit 21b controls the motor 19a at a specified assist output. The specified assist output in step S27 is the torque and rotational speed of the motor 19a that can satisfy the assist conditions regardless of the current gear.

[0098] In the second embodiment, the specified assist output is set so that the assist output is as large as possible within the range that can satisfy the assist conditions. For example, the assist conditions include the condition that the vehicle speed of the human-powered vehicle 1 is less than or equal to the upper limit speed. For example, the vehicle speed of the human-powered vehicle 1 increases as the rotational speed of the motor 19a increases when the gear is not shifted in walk mode. The specified assist output is set to the rotational speed of the motor 19a such that the human-powered vehicle 1 moves at the upper limit speed in the smallest gear. After performing the processing in step S27, the control unit 21b proceeds to step S28.

[0099] In step S28, the control unit 21b terminates its operation in walk mode if it receives an instruction to terminate walk mode, similar to step S16 of the first control flow. If there is no instruction to terminate walk mode, the control unit 21b proceeds to step S21.

[0100] The slip determination condition is met when, in step S22 of the second control flow, at least one of the pitch angle and the road surface inclination angle is greater than or equal to a predetermined threshold, and in step S23, the current step number is not a specific step. When the slip determination condition is met, the control unit 21b determines that the wheel slip-related conditions meet the predetermined conditions.

[0101] The control unit 21b can appropriately control the gear ratio according to the gear when a user pushes the human-powered vehicle 1 uphill by executing the second control flow. For example, when a user pushes the human-powered vehicle 1 uphill with the gear shifted to a gear lower than a specific gear, the control unit 21b can change the gear of the chain 16f to a higher gear than the current one to reduce the gear ratio and make it less likely for the wheels 15 to slip when going uphill.

[0102] For example, when a user pushes the human-powered vehicle 1, which has been shifted to a gear higher than a specific gear while climbing a slope, the control unit 21b can change the chain 16f to a lower gear than it currently is, increasing the tooth ratio and thus increasing the torque acting on the rear wheel 15b. By increasing the torque acting on the rear wheel 15b, the burden on the user when pushing the human-powered vehicle 1 while climbing a slope can be reduced.

[0103] The control unit 21b can appropriately control the assist force when a user pushes the human-powered vehicle 1 uphill by executing a second control flow. For example, when a user pushes the human-powered vehicle 1 uphill at a gear below a specific gear, the control unit 21b can reduce the assist force and suppress wheel slippage. For example, when a user pushes the human-powered vehicle 1 uphill at a gear higher than a specific gear, the control unit 21b can increase the assist output and reduce the burden on the user when pushing the human-powered vehicle 1 uphill.

[0104] In step S22 of the second control flow, the control unit 21b may change the step to which it proceeds according to information other than the pitch angle and the road surface inclination angle. For example, the control unit 21b may change the step to which it proceeds according to at least one of the road surface unevenness, the amount of sand, the amount of mud, and the amount of snow.

[0105] For example, the control unit 21b may proceed to step S23 if the road surface irregularities are less than a predetermined threshold and control at least one of the assist output and the gear shift. For example, the control unit 21b may proceed to step S23 if at least one of the road surface irregularities, the amount of sand, the amount of mud, and the amount of snow is greater than or equal to a predetermined threshold and control at least one of the assist output and the gear shift. The control unit 21b can control the gear ratio according to the road surface conditions by changing the step to which it proceeds according to at least one of the road surface irregularities, the amount of sand, the amount of mud, and the amount of snow.

[0106] (Third embodiment) The control device 21 of the third embodiment will be described. Figure 7 will be used to describe the control device 21 of the third embodiment. Components common to the first and second embodiments will be denoted by the same reference numerals as in the first and second embodiments, and redundant descriptions will be omitted.

[0107] The wheel slip-related conditions of the third embodiment are conditions that can determine whether or not the wheel 15 is slipping. At least one slip determination condition is defined based on a parameter that varies depending on whether or not the wheel 15 is slipping. For example, at least one slip determination condition is defined based on at least one of the vehicle speed of the human-powered vehicle 1, the wheel speed, and the acceleration. At least one slip determination condition is met when the wheel 15 is slipping. The control unit 21b changes the assist output to stop the slip when at least one slip determination condition is met.

[0108] By changing the assist output when at least one slip detection condition is met, the control unit 21b can change the output of the motor 19a in walk mode according to at least one of the vehicle speed, wheel speed, and acceleration of the human-powered vehicle 1. An example of the control performed by the control unit 21b is described. Figure 7 is used to describe an example of the control performed by the control unit 21b. The control unit 21b starts the third control flow according to the flowchart shown in Figure 7, similar to the first embodiment.

[0109] As shown in Figure 7, in step S31, the control unit 21b controls the motor 19a in walk mode. After performing the processing in step S31, the control unit 21b proceeds to step S32.

[0110] In step S32, the control unit 21b controls the motor 19a at the specified assist output, similar to step S27 of the second control flow. By controlling the motor 19a in the same way as in step S27, the control unit 21b can control the assist force so that the assist condition is met regardless of the current gear. For example, the control unit 21b can apply assist force to the human-powered vehicle 1 so that the vehicle speed of the human-powered vehicle 1 is below the upper limit speed, regardless of the current gear. After performing the processing in step S32, the control unit 21b proceeds to step S33.

[0111] In step S33, if the control unit 21b determines that the wheel 15 is not slipping, it proceeds to step S36. If the control unit 21b determines that the wheel 15 is slipping, it proceeds to step S34. The method for determining whether the wheel 15 is slipping will be described later.

[0112] In step S34, the control unit 21b reduces the assist output. After performing the processing in step S34, the control unit 21b proceeds to step S35.

[0113] In step S35, if the control unit 21b determines that the wheel 15 will continue to slip, it proceeds to step S34. If the control unit 21b determines that the wheel 15 will stop slipping, it proceeds to step S37.

[0114] In step S36, the control unit 21b continues the specified assist output from step S32 so that the assist output does not increase or decrease. After performing the processing in step S36, the control unit 21b proceeds to step S37.

[0115] In step S37, the control unit 21b terminates its operation in walk mode if it receives an instruction to terminate walk mode, similar to step S16 of the first control flow. If there is no instruction to terminate walk mode, the control unit 21b proceeds to step S31.

[0116] The slip determination condition is met when it is determined that the wheel 15 slips in step S33 of the third control flow. When the slip determination condition is met, the control unit 21b determines that the wheel slip-related conditions meet predetermined conditions.

[0117] The control unit 21b reduces the assist output when the wheel 15 slips by executing the third control flow. By reducing the assist output, the control unit 21b reduces the torque of the wheel 15, making it easier to stop the wheel 15 from slipping.

[0118] The control unit 21b can control the assist force to suppress wheel slip in the human-powered vehicle 1, which cannot detect the current gear, by executing the third control flow.

[0119] An example of a method for determining wheel slip in steps S33 and S35 is described. For example, when wheel 15 slips, the rotational speed of wheel 15, the vehicle speed of the human-powered vehicle 1, and the acceleration along the direction of travel of the human-powered vehicle 1 may fluctuate rapidly. The control unit 21b can determine that wheel 15 is slipping if at least one of the rotational speed of wheel 15, the vehicle speed of the human-powered vehicle 1, and the acceleration along the direction of travel of the human-powered vehicle 1 fluctuates rapidly.

[0120] The control unit 21b determines whether or not the wheel 15 is slipping based on information regarding the slipping wheel 15 and information regarding parts other than the slipping wheel 15.

[0121] For example, if either the front wheel 15a or the rear wheel 15b slips, the difference in rotational speed between the front wheel 15a and the rear wheel 15b may exceed a predetermined value. Therefore, the control unit 21b can determine whether or not the wheel 15 is slipping by comparing the rotational speeds of the front wheel 15a and the rear wheel 15b. For example, the control unit 21b can determine that the wheel 15 is slipping if the difference in rotational speed between the front wheel 15a and the rear wheel 15b exceeds a predetermined value.

[0122] For example, if wheel 15 slips, the rotational speed of the slipped wheel 15 may become excessively high relative to the vehicle speed of the human-powered vehicle 1 and the acceleration along the direction of travel of the human-powered vehicle 1. The control unit 21b can determine whether or not wheel 15 is slipping by comparing at least one of the vehicle speed of the human-powered vehicle 1 and the acceleration along the direction of travel of the human-powered vehicle 1 with the rotational speed of wheel 15.

[0123] The control unit 21b can obtain the vehicle speed from the vehicle speed detection unit 24. When the vehicle speed of the human-powered vehicle 1 is compared with the rotational speed of the wheels 15, the vehicle speed detection unit 24 detects the vehicle speed of the human-powered vehicle 1 based on information different from the rotational speed of the wheels 15, so that the control unit 21b can determine whether or not the wheels 15 are slipping. For example, the vehicle speed detection unit 24 is configured to detect the vehicle speed of the human-powered vehicle 1 based on the position information of the human-powered vehicle 1.

[0124] For example, if the vehicle speed detection unit 24 detects the vehicle speed of the human-powered vehicle 1 based on the rotational speed of the wheels 15, the vehicle speed detected by the vehicle speed detection unit 24 may become excessively high relative to the acceleration along the direction of travel of the human-powered vehicle 1 if the wheels 15 slip. The control unit 21b can determine whether or not the wheels 15 are slipping by comparing the vehicle speed detected by the vehicle speed detection unit 24 with the acceleration along the direction of travel of the human-powered vehicle 1.

[0125] In steps S33 and S35, by comparing at least two of the rotational speed of the wheels 15, the vehicle speed of the human-powered vehicle 1, and the acceleration along the direction of travel of the human-powered vehicle 1, the control unit 21b can change the output of the motor 19a in walk mode in accordance with the comparison of at least two of the vehicle speed of the human-powered vehicle 1, the wheel speed, and the acceleration.

[0126] (Fourth Embodiment) The control device 21 of the fourth embodiment will be described. Figure 8 will be used to describe the control device 21 of the fourth embodiment. Components common to the first to third embodiments will be denoted by the same reference numerals as in the first to third embodiments, and redundant descriptions will be omitted.

[0127] In the fourth embodiment, the control unit 21b is configured to execute a fourth control flow corresponding to the third control flow of the third embodiment. The fourth control flow is a control flow obtained by adding step S44 to the third control flow. If the control unit 21b determines in step S33 that the wheel 15 is slipping, it proceeds to at least one of step S33 and step S44.

[0128] In step S44, the control unit 21b changes the gear position of the transmission 17 to a specified gear. The specified gear in step S44 is a gear position with a gear ratio that is one or more gears smaller than the gear ratio at the time of transitioning to step S44. For example, the specified gear may have a gear ratio that is only one gear smaller than the gear ratio at the time of transitioning to step S44. After performing the processing in step S44, the control unit 21b proceeds to step S35.

[0129] The control unit 21b, by executing the fourth control flow, can, when the wheel 15 slips, switch the chain 16f to a higher gear than currently used, thereby reducing the tooth ratio and decreasing the torque acting on the rear wheel 15b. By reducing the torque acting on the rear wheel 15b, it becomes easier to stop the wheel 15 from slipping.

[0130] If the control unit 21b performs both step S34 and step S44, it may adjust the assist output in step S34 according to the specified stage of step S44. The order in which steps S34 and S44 are performed is not particularly limited.

[0131] (modified version) The descriptions of each embodiment are illustrative of possible forms of the present invention and are not intended to limit it. The present invention may take the form of, for example, variations of each embodiment shown below, and combinations of at least two non-inconsistent variations.

[0132] For example, the configuration of the control device 21 in each embodiment is just one example, and the control device 21 may include various devices not shown in each embodiment, or it may have a configuration that does not include some of the various devices shown in each embodiment.

[0133] The various thresholds used in the control exemplified in each embodiment are not limited and may be set arbitrarily. The various thresholds may also be arbitrarily changed by operating a predetermined control device or the like.

[0134] The configurations exemplified in each embodiment may be combined with each other to the extent that they do not contradict each other. For example, the second and third embodiments may be combined to adjust the assist output according to both the slip of the wheel 15 and the inclination state. For example, if the control unit 21b determines that the wheel 15 is slipping in step S33 of the third control flow shown in Figure 7, it may adjust the assist output according to the inclination state. For example, the control unit 21b may reduce the assist output as the pitch angle of the human-powered vehicle 1 and the inclination angle of the road surface increase.

[0135] For example, the second and fourth embodiments may be combined to control the gear shift according to the slip of the wheel 15, the current gear, and the inclination state. For example, the control unit 21b may control the gear shift according to the inclination state in step S44 of the fourth control flow shown in Figure 8. For example, the control unit 21b may control the gear shift such that the gear ratio becomes smaller as the pitch angle of the human-powered vehicle 1 and the inclination angle of the road surface increase.

[0136] The processing content and processing order of the flowcharts exemplified in each embodiment are examples only, and the processing content and processing order can be changed as appropriate within the scope of the present invention.

[0137] For example, in the second control flow shown in Figure 6, steps S23 and S26 may be omitted, and the assist output and gear shift may be controlled according to the tilt determination result in step S22.

[0138] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, the expression "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, the expression "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options. For example, the expression "at least one of A and B" means (1) A only, and (2) B only, and (3) both A and B. For example, the expression "at least one of A, B, and C" means (1) A only, and (2) B only, (3) C only, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all of A, B, and C. In other words, the expression “at least one of A and B” as used herein does not mean “at least one A and at least one B.” [Explanation of Symbols]

[0139] 1...Human-powered vehicle, 16d...Front sprocket, 16e...Rear sprocket, 16f...Chain, 17...Transmission, 19a...Motor, 21...Control device, 21b...Control unit

Claims

1. A control device for a human-powered vehicle, The vehicle comprises a motor that provides assisting force to the human-powered vehicle, and a control unit configured to control the transmission. The control unit, A control device that controls the transmission in a walk mode in which the motor can be driven in response to the operation of an operating unit that can be operated by the user, such that the ratio of the total number of teeth of the rear sprocket of the human-powered vehicle to the total number of teeth of the front sprocket of the human-powered vehicle becomes smaller when the wheel slip-related conditions satisfy predetermined conditions.

2. The control device according to claim 1, wherein the control unit controls the transmission so that, in the walk mode, when the wheel slip-related conditions satisfy predetermined conditions, the chain moves from the gear currently engaged to the top gear on at least one of the front sprocket and the rear sprocket.

3. The control device according to claim 1, wherein the predetermined condition is satisfied when at least one of the conditions relating to the posture of the human-powered vehicle and the conditions relating to the driving state is satisfied.

4. The control device according to claim 3, wherein the posture includes the pitch angle of the human-powered vehicle.

5. The control device according to claim 3, wherein the driving state includes at least one of the inclination angle of the road surface on which the human-powered vehicle is traveling, and the condition of the road surface.

6. The control device according to claim 1, wherein the control unit changes the output of the motor in accordance with at least one of the vehicle speed, wheel speed, and acceleration of the human-powered vehicle in the walk mode.

7. The control device according to claim 6, wherein the control unit changes the output of the motor in the walk mode according to a comparison of at least two of the vehicle speed, wheel speed, and acceleration of the human-powered vehicle.

8. The control device according to claim 1, wherein the control unit, when the wheel slip-related conditions in the walk mode satisfy predetermined conditions, first reduces the output of the motor and then controls the transmission so that the ratio of the total number of teeth of the rear sprocket of the human-powered vehicle to the total number of teeth of the front sprocket of the human-powered vehicle becomes smaller.

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