Electrically assisted bicycle and motor control device

Abstract

To improve an assisted feeling during traveling on a curve, in an electric assisted bicycle.SOLUTION: An electric assisted bicycle 10 includes: a vehicle body motion sensor 63 that detects a change in a posture of a vehicle body relative to a road surface; a torque sensor 62 that detects a pedaling force of a pedal; a motor 3 that generates an assisting force for assisting the pedaling force; a motor control unit 5 that controls the assisting force of the motor 3 according to the pedaling force; and a sharp curve travel detection unit 6 that, based on information obtained from the vehicle body motion sensor 63, detects the electric assisted bicycle 10 traveling on a sharp curve in a state where the vehicle body is leaned at a predetermined angle or more in a right and left direction from an upright state. The motor control unit 5 controls the assisting force according to a detection result of the sharp curve travel detection unit 6.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electrically assisted bicycle and a motor control device for an electrically assisted bicycle. [Background technology]

[0002] An electrically assisted bicycle uses a motor to generate an auxiliary force that assists the rider in pedaling. The auxiliary force of the motor is controlled according to the pedaling force. In addition to the pedaling force, the auxiliary force of the motor may also be controlled based on information from a sensor equipped on the electrically assisted bicycle.

[0003] JP 2019-116241 A discloses a bicycle equipped with a motor that serves as the driving source for the electric assist function, a six-axis sensor that measures acceleration in each of three orthogonal axes and angular velocity around the three axes, and a control unit that controls the output of the motor based on the measurement results of the six-axis sensor.

[0004] JP 2019-137231 A discloses a control device for a human-powered vehicle that includes a control unit that controls a motor that assists the propulsion of the vehicle and drives the motor according to human-powered driving force when the vehicle's traveling speed is below a predetermined speed. This control unit changes the predetermined speed according to at least one of the state of the vehicle and the state of the road, and does not assist the propulsion of the vehicle when the vehicle's traveling speed is equal to or higher than the predetermined speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-116241 A [Patent Document 2] JP 2019-137231 A Summary of the Invention [Problem to be solved by the invention]

[0006] There are various possible riding conditions for a bicycle. The inventors have studied how to improve the assist feeling by providing pedaling force assistance from a motor for each riding condition. In the study, it was found that when the bicycle is traveling around a curve, an assist force is applied and the rider may feel the sensation of the bicycle's riding line swinging to the outside of the turn. In addition, when the bicycle is turning, the rider often does not step on the pedals. Therefore, it was also found that the rider may feel a lack of assistance during or after the turn.

[0007] Therefore, an object of the present application is to provide an electrically assisted bicycle that can improve the feeling of assistance when traveling around curves. [Means for solving the problem]

[0008] An electrically assisted bicycle in an embodiment of the present invention comprises a body motion sensor that detects changes in the posture of the body of the electrically assisted bicycle relative to the road surface, a torque sensor that detects the force applied to a pedal connected to the crankshaft of the electrically assisted bicycle, a motor that generates an auxiliary force to supplement the pedal force, a motor control unit that controls the auxiliary force of the motor in accordance with the pedal force, and a sharp curve traveling detection unit that detects, based on information obtained from the body motion sensor, when the electrically assisted bicycle is traveling around a sharp curve with the body tilted at a predetermined angle or more from an upright position. The motor control unit controls the auxiliary force in accordance with the detection result of the sharp curve traveling detection unit. Effect of the Invention

[0009] According to the present disclosure, the feeling of assistance when riding an electrically assisted bicycle around a curve can be improved. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a left side view showing an electrically assisted bicycle according to the present embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of the configuration of the electrically assisted bicycle shown in FIG. [Diagram 3]FIG. 3 is a diagram showing an example of the configuration of the motor control device 4 in this embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of the operation of the motor control device 4 shown in FIG. [Diagram 5] FIG. 5 is a flowchart showing an example of the processes of S12 and S13 in FIG. [Figure 6] FIG. 6 is a diagram showing an example of changes over time in the yaw angular velocity, roll angular velocity, and pitch angular velocity of an electrically assisted bicycle. [Figure 7] FIG. 7 is a graph showing an example of changes over time in the yaw angular velocity, the pitch angular velocity, and the sharp curve detection result. [Figure 8] FIG. 8 is a plot of the trajectory of the route traveled by the electrically assisted bicycle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The inventors have studied configurations for improving the assist feeling when traveling around a curve. They have studied the assist feeling of the rider when traveling around a curve in various states. As a result of their studies, they have found that adjustment of motor control is often necessary, particularly when traveling around a sharp curve with the body tilted from an upright position. In other words, they have found that when an electrically assisted bicycle travels around a curve that is so sharp that it tilts the body from an upright position, the assist feeling can be improved by adjusting the control of the assist force provided by the motor. Based on this knowledge, they have come up with the following embodiment.

[0012] An electrically assisted bicycle in an embodiment of the present invention comprises a body motion sensor that detects changes in the posture of the body of the electrically assisted bicycle relative to the road surface, a torque sensor that detects the force applied to a pedal connected to the crankshaft of the electrically assisted bicycle, a motor that generates an auxiliary force to supplement the pedal force, a motor control unit that controls the auxiliary force of the motor in accordance with the pedal force, and a sharp curve traveling detection unit that detects, based on information obtained from the body motion sensor, when the electrically assisted bicycle is traveling around a sharp curve with the body tilted at a predetermined angle or more from an upright position. The motor control unit controls the auxiliary force in accordance with the detection result of the sharp curve traveling detection unit.

[0013] According to the above configuration, the sharp curve detection unit can detect when the electrically assisted bicycle is traveling around a sharp curve that causes the body to tilt left or right by a predetermined angle or more from an upright position. The motor control unit controls the motor assist force according to the pedaling force in response to the detection result of such a sharp curve. This allows motor control suitable for curve traveling when the curve is sharp enough that adjustment of the assist force can be utilized. As a result, the assist feeling when traveling around a curve can be improved.

[0014] The sharp curve travel detection unit detects that the electric-assisted bicycle is traveling around a sharp curve with the body tilted at a predetermined angle or more from an upright state to the left or right, whichever is the turning direction. The predetermined angle is the lower limit of the tilt angle when traveling around a sharp curve where motor control specialized for curves is likely to be utilized. In other words, it is a tilt angle that is a reference for determining that the electric-assisted bicycle is traveling around a sharp curve from the viewpoint of assist force control. The predetermined angle is not particularly limited, but can be at least 10 degrees, for example. This predetermined angle may change depending on the vehicle speed of the electric-assisted bicycle. Note that the information of the vehicle body motion sensor used to detect that the vehicle body is traveling around a sharp curve with the body tilted at a predetermined angle or more in the left / right direction can be, for example, a physical quantity related to any one of the yaw angle, roll angle, or pitch angle of the vehicle body. For example, the sharp curve travel detection unit can detect that the vehicle body is traveling around a sharp curve with the body tilted at a predetermined angle or more from an upright state by using the roll angle or roll angular velocity obtained from the angular velocity sensor, but the detection form is not limited to this. This detection does not necessarily require the use of a physical quantity related to the roll angle.

[0015] The upright state is a state in which the vertical direction of the body (body frame) of the electrically assisted bicycle coincides with the direction of gravity. When the body is tilted left or right from the upright state, the vertical axis of the body is tilted left or right with respect to the direction of gravity.

[0016] When the sharp curve detection unit detects a sharp curve, the motor control unit can control the assist force specialized for a sharp curve, that is, control the assist force for a sharp curve. For example, when the sharp curve detection unit detects a sharp curve, the motor control unit may control the motor differently from when the sharp curve detection unit does not detect a sharp curve. An example of a form of different motor control is a form of differently determining the assist force according to the pedal force. In this case, the way in which the assist force according to the pedal force is controlled differs between when a sharp curve is detected and when it is not detected. Note that the way in which the assist force according to the pedal force is controlled may be the same when a sharp curve is detected and when it is not detected.

[0017] In addition, changes to the control of the auxiliary force according to the pedaling force include, for example, changes to the waveform of the auxiliary force according to the pedaling force, changes to the magnitude of the auxiliary force relative to the pedaling force (assist ratio), changes to the responsiveness of changes in the auxiliary force to changes in the pedaling force, changes to the assist mode, changes to the upper limit of the auxiliary force, and changes to other assist conditions.

[0018] The vehicle body motion sensor may be a sensor that detects at least two of the yaw angular velocity, pitch angular velocity, and roll angular velocity of the vehicle body of the electrically assisted bicycle, and / or at least two of the acceleration in the front-rear direction, the acceleration in the left-right direction, and the acceleration in the up-down direction of the vehicle body. The vehicle body motion sensor may include an angular velocity sensor that detects at least two of the yaw angular velocity, pitch angular velocity, and roll angular velocity of the vehicle body, or an acceleration sensor that detects at least two of the acceleration in the front-rear direction, the acceleration in the left-right direction, and the acceleration in the up-down direction of the vehicle body. Alternatively, the vehicle body motion sensor may include both an angular velocity sensor and an acceleration sensor.

[0019] The sharp curve detection unit may be configured to detect when the electric assisted bicycle is traveling around a sharp curve in an inclined state in which the body is tilted to the left or right at a predetermined angle or more from an upright position so that the pitch angular velocity in the direction in which the front of the body faces upward and the rear of the body faces downward increases.

[0020] The inventor discovered that motor control specialized for sharp curves is effective when an electrically assisted bicycle makes a sharp curve with the body tilted to such an extent that the pitch angular velocity in the upward direction of the front of the body increases. Therefore, when it is detected that the bicycle is making a sharp curve with the body tilted to such an extent that the pitch angular velocity increases, the assist force is controlled in accordance with the detection result, thereby making it possible to efficiently improve the feeling of assistance when making a curve with a simple configuration.

[0021] The sharp curve detection unit may detect that the electrically assisted bicycle is traveling around a sharp curve in a leaning state based on at least two of the yaw angle or yaw angular velocity, roll angle or roll angular velocity, and pitch angle or pitch angular velocity of the electrically assisted bicycle obtained from the vehicle body motion sensor. This makes it possible to efficiently detect traveling around a sharp curve in a leaning state using information from the vehicle body motion sensor.

[0022] The sharp curve detection unit may detect that the electric assisted bicycle is traveling around a sharp curve in the leaning state when the yaw angle or yaw angular velocity of the electric assisted bicycle is equal to or greater than a first threshold value and the pitch angle or pitch angular velocity of the electric assisted bicycle is equal to or greater than a second threshold value. In this case, it is possible to determine whether the electric assisted bicycle is traveling around a curve based on the magnitude of the yaw angle or yaw angular velocity. Furthermore, it is possible to distinguish, based on the pitch angle or pitch angular velocity, whether the electric assisted bicycle is traveling around a curve with the body upright (upright state) or with the body tilted (i.e., traveling around a sharp curve). This makes it possible to more efficiently detect traveling around a sharp curve in a leaning state using information from the body motion sensor.

[0023] At least one of the first threshold value and the second threshold value may vary depending on the vehicle speed of the electrically assisted bicycle. This makes it possible to detect a sharp curve while leaning, taking into account the vehicle speed of the electrically assisted bicycle. In this case, the electrically assisted bicycle may be equipped with a vehicle speed sensor that detects the speed in the traveling direction (front-rear direction of the body) of the electrically assisted bicycle.

[0024] The motor control unit may control the assist force according to the pedaling force differently depending on whether it is detected that the electrically assisted bicycle is traveling around a sharp curve in the leaning state or not. This makes it possible to improve the feeling of assistance when turning a curve by changing the assist force according to the pedaling force when the electrically assisted bicycle is traveling around a sharp curve with the body leaning.

[0025] The motor control unit may control the motor so that, when it is detected that the electrically assisted bicycle is traveling around a sharp curve in the leaning state, the assist force according to the pedaling force is smaller than when it is not detected. This makes it possible to suppress the assist when traveling around a sharp curve in the leaning state. For example, it is possible to prevent the rider from feeling that the traveling line is swaying to the outside of the turn due to a stronger assist when traveling around a sharp curve in the leaning state.

[0026] The sharp curve detection unit may detect the start and end of the electric-assisted bicycle traveling around a sharp curve in the leaning state. In this case, the motor control unit can vary the control of the assist force according to the pedaling force in a period based on at least one of the start and end of the electric-assisted bicycle traveling around a sharp curve in the leaning state. This makes it possible to control the assist force appropriate for a sharp curve at an appropriate timing. This makes it possible to efficiently improve the feeling of assistance when traveling around a curve.

[0027] The motor control unit may vary the control of the assist force according to the pedaling force for a predetermined period of time after the electric assisted bicycle has finished traveling around a sharp curve in the leaning state. This allows for control of the assist force specialized for traveling around a sharp curve for a certain period of time after the electric assisted bicycle has finished traveling around a sharp curve in the leaning state. This makes it possible to improve the feeling of assistance immediately after the sharp curve is made.

[0028] An embodiment of the present invention also includes a motor control device that controls a motor that generates an auxiliary force to assist the pedal force of an electrically assisted bicycle. The motor control device includes a motor control unit that controls the auxiliary force of the motor in response to the pedal force detected by a torque sensor that detects the pedal force, and a sharp curve traveling detection unit that detects whether the electrically assisted bicycle is traveling around a sharp curve in an inclined state in which the body is tilted to the left or right by a predetermined angle or more from an upright state, based on information obtained from an angular velocity sensor that detects at least two of the yaw angular velocity, pitch angular velocity, and roll angular velocity of the electrically assisted bicycle. The motor control unit controls the auxiliary force in response to the detection result of the sharp curve traveling detection unit.

[0029] An electric-assisted bicycle according to an embodiment of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are given the same reference numerals, and the description of those parts will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components and the dimensional ratios of each component. In the following description, the front-rear, left-right, and up-down directions of the electric-assisted bicycle refer to the front-rear, left-right, and up-down directions based on the state in which the rider sits on the saddle (seat 24) and grips the handlebars 23. The front-rear, left-right, and up-down directions of the electric-assisted bicycle are the same as the front-rear, left-right, and up-down directions of the body of the electric-assisted bicycle, i.e., the body frame. Furthermore, the traveling direction of the electric-assisted bicycle is the same as the front-rear direction of the electric-assisted bicycle. The following embodiments are illustrative, and the present invention is not limited to the following embodiments.

[0030] <Example of the overall configuration of an electric assisted bicycle> Fig. 1 is a left side view showing an electrically assisted bicycle 10 according to this embodiment. The symbols F, B, U, and D in Fig. 1 represent front, rear, top, and bottom, respectively.

[0031] As shown in FIG. 1, the electrically assisted bicycle 10 has a body frame 11. The body frame 11 extends in the front-rear direction. The body frame 11 has a head pipe 12, an upper frame 13u, a down frame 13d, a seat frame 14, a pair of chain stays 16, and a pair of seat stays 17. The head pipe 12 is disposed at the front of the electrically assisted bicycle 10. The front ends of the down frame 13d and the upper frame 13u are connected to the head pipe 12. The down frame 13d and the upper frame 13u extend in the front-rear direction. The down frame 13d and the upper frame 13u extend diagonally downward. The upper frame 13u is located above the down frame 13d. The rear end of the upper frame 13u is connected to the seat frame 14. The rear end of the down frame 13d is connected to a bracket 15. The lower end of the seat frame 14 is connected to the bracket 15. The seat frame 14 extends upward and diagonally backward from the bracket 15. The body frame 11 may have a configuration without the upper frame 13u.

[0032] A handle stem (steering column) 25 is rotatably inserted into the head pipe 12. A handle 23 is fixed to the upper end of the handle stem 25. A front fork 26 is fixed to the lower end of the handle stem 25. A front wheel 21 is rotatably supported by an axle 27 at the lower end of the front fork 26.

[0033] Grips are attached to the left and right ends of the handlebar 23. A left brake lever 74 is attached to the left part of the handlebar 23, and a right brake lever 74 is attached to the right part of the handlebar 23. The left brake lever 74 is a lever for operating a brake 76 of the rear wheel 22. The right brake lever 74 is a lever for operating a brake 75 of the front wheel 21.

[0034] A seat pipe 28 is inserted into the cylindrical seat frame 14. The seat 24 is provided at the upper end of the seat pipe 28. In this manner, the body frame 11 rotatably supports the handle stem 25 at the front, and rotatably supports the rear wheel 22 at the rear. The seat 24 and a drive unit 40 are also attached to the body frame 11.

[0035] A pair of chain stays 16 are connected to the rear end of the bracket 15. The pair of chain stays 16 are arranged to sandwich the rear wheel 22 from the left and right. One end of a seat stay 17 is connected to the rear end of each chain stay 16. The pair of seat stays 17 are arranged to sandwich the rear wheel 22 from the left and right. The other end of each seat stay 17 is connected to an upper part of the seat frame 14. The rear wheel 22 is rotatably supported by an axle 29 at the rear ends of the pair of chain stays 16.

[0036] The front fork 26 is provided with a vehicle speed sensor (speed sensor) 61 that detects the rotation of the front wheel 21. The vehicle speed sensor 61 has, for example, a detectable element that rotates together with the front wheel 21, and a detection element that is fixed to the body frame 11 and detects the rotation of the detectable element. The detection element detects the detectable element mechanically, magnetically, or optically. Note that the vehicle speed sensor 61 is not limited to the front wheel 21, and may be one that detects the rotation of a rotating body that rotates as the electrically assisted bicycle 10 travels, such as the rear wheel 22, the motor 3, the crankshaft 41, a transmission gear, a chain, etc.

[0037] A vehicle body motion sensor 63 is attached to the vehicle body frame 11. The vehicle body motion sensor 63 may be, for example, an angular velocity sensor (gyro sensor) that detects the angular velocity of the vehicle body frame 11 (vehicle body). Or, the vehicle body motion sensor 63 may be an acceleration sensor that detects the acceleration of the vehicle body frame 11 (vehicle body). Or, the vehicle body motion sensor 63 may be a six-axis sensor including an angular velocity sensor and an acceleration sensor. The vehicle body motion sensor 63 is fixed to the vehicle body frame 11. The attachment position of the vehicle body motion sensor 63 is not limited to the down frame 13d. For example, the vehicle body motion sensor 63 may be attached to another frame such as the upper frame 13u, the bracket 15, or the drive unit 40.

[0038] The drive unit 40 is attached below the bracket 15 with fastening fittings (not shown). The drive unit 40 has a housing 51 that forms the outer shape of the drive unit 40. The motor 3 is stored inside the housing 51. The crankshaft 41 penetrates the housing 51 in the left-right direction. The crankshaft 41 is rotatably supported by the housing 51 via a plurality of bearings.

[0039] A torque sensor 62 is provided around the crankshaft 41 to detect the pedaling force of the occupant. The torque sensor 62 detects the torque that rotates the crankshaft 41 around its axis. The torque sensor 62 may be, for example, a non-contact type such as a magnetostrictive type, or a contact type such as an elastic body displacement detection type. The magnetostrictive torque sensor has a magnetostrictive effect and includes a magnetostrictive material that receives the rotational force of the crankshaft, and a detection coil that detects the change in magnetic permeability due to the force of the magnetostrictive material.

[0040] Crank arms 31 are attached to both ends of the crankshaft 41. Pedals 33 are attached to the ends of the crank arms 31, respectively. When the rider steps on the pedals 33, the crankshaft 41 rotates. Although not shown, the electrically assisted bicycle 10 is provided with a drive sprocket that rotates together with the crankshaft 41 and a driven sprocket that rotates together with the rear wheel 22. A chain 46 is wound between the drive sprocket and the driven sprocket. Note that a belt, a shaft, or the like may be used instead of the chain 46. A one-way clutch 49 (see FIG. 2) is provided on the rotation transmission path from the driven sprocket to the rear wheel 22. The one-way clutch 49 transmits rotation in the forward rotation direction (forward rotation) and does not transmit rotation in the reverse rotation direction (reverse rotation).

[0041] A transmission mechanism (not shown) that transmits the rotation of the motor 3 to the drive sprocket (or the chain 46) is provided within the drive unit 40. The transmission mechanism includes, for example, a reducer (reduction gear) 42 (see FIG. 2). The reducer 42 reduces the rotation of the motor and transmits it to the drive sprocket. The transmission mechanism also includes a combining mechanism that combines the rotation of the crankshaft 41 and the rotation of the motor 3 and transmits it to the drive sprocket. The combining mechanism has, for example, a cylindrical member. The crankshaft 41 is disposed inside the cylindrical member. The drive sprocket is attached to the combining mechanism. The combining mechanism rotates around the same rotation axis as the crankshaft 41 and the drive sprocket. One-way clutches 43 and 44 (see FIG. 2) may be provided on the rotation transmission path from the crankshaft 41 to the combining mechanism and on the rotation transmission path from the motor 3 to the combining mechanism. The rotation force transmitted from the motor 3 to the driving sprocket via the transmission mechanism becomes the auxiliary force of the motor 3.

[0042] A battery unit 35 is disposed on the down frame 13d. The battery unit 35 supplies power to the motor 3 of the drive unit 40. The battery unit 35 has a battery and a battery control unit (not shown). The battery is a rechargeable battery that can be charged and discharged. The battery control unit controls charging and discharging of the battery, and monitors the output current and remaining capacity of the battery. The battery unit 35 may be disposed on the seat frame 14 or the upper frame 13u.

[0043] A display device 37 is provided on the handlebar 23. The display device 37 has, for example, a display and an input unit such as buttons for accepting user operations or a touch panel. The display device 37 displays various information related to the electric assisted bicycle 10. Note that the display device 37 may be omitted.

[0044] Fig. 2 is a block diagram showing an example of the mechanical and electrical connection configuration of the components of the electrically assisted bicycle 10 shown in Fig. 1. In the example shown in Fig. 2, the rotation of the pedal crank (including the pedal 33, the crank arm 31, and the crank shaft 41) is transmitted to a resultant power transmission path 45 via a one-way clutch 43. The rotation of the motor 3 is transmitted to the resultant power transmission path 45 via a speed reducer 42 and the one-way clutch 43. The resultant power transmission path 45 includes the combining mechanism, the driving sprocket, the chain 46, and the driven sprocket. In the resultant power transmission path 45, the power is transmitted in the order of the combining mechanism, the driving sprocket, the chain 46, and the driven sprocket. The rotation of the driven sprocket is transmitted to the rear wheel 22 via a drive shaft 47, a speed change mechanism 48, and a one-way clutch 49.

[0045] The speed change mechanism 48 is a mechanism that changes the gear ratio in response to the operation of the speed change operating device 38 by the rider. The speed change operating device 38 is attached to, for example, the handlebars 23 (FIG. 1). In this example, the speed change mechanism 48 is an internal transmission provided between the drive shaft 47 and the rear wheel 22, but the speed change mechanism 48 may be an external transmission. When the speed change mechanism 48 is an external transmission, a multi-stage sprocket may be used as the driven sprocket. In this case, the multi-stage sprocket around which the chain 46 is wound is switched in response to the operation of the speed change operating device 38. The one-way clutch 49 transmits the rotation of the speed change mechanism 48 to the rear wheel 22 only when the rotation speed of the output shaft of the speed change mechanism 48 is faster than the rotation speed of the rear wheel 22. When the rotation speed of the output shaft of the speed change mechanism 48 is slower than the rotation speed of the rear wheel 22, the one-way clutch 49 does not transmit the rotation of the speed change mechanism 48 to the rear wheel 22. The speed change mechanism 48 and the speed change operating device 38 may be omitted.

[0046] The pedaling force generated by the rider depressing the pedal 33 rotates the drive sprocket in the forward rotation direction, and is transmitted as a driving force to rotate the rear wheel 22 in the forward rotation direction via the chain 46. In addition, the rotational force generated by the operation of the motor 3 rotates the crankshaft 41 in the forward rotation direction. As a result, the rotational force output from the motor 3 assists (supports) the pedaling force generated by the rider depressing the pedal 33.

[0047] The electrically assisted bicycle 10 has a motor control device 4 that controls the motor 3. For example, the motor control device 4 is configured by electronic equipment mounted on a board inside the housing 51 of the drive unit 40. The electronic equipment has, for example, a processor or an electronic circuit. The motor control device 4 is electrically connected to at least a torque sensor 62, a vehicle body motion sensor 63, and the motor 3. In the example shown in FIG. 2, the motor control device 4 is connected to a crank rotation sensor 64, a motor rotation sensor 65, and a vehicle speed sensor 61. These connections may be wired or wireless.

[0048] The crank rotation sensor 64 detects the rotation of the crankshaft 41. The crank rotation sensor 64 may have, for example, a detected element that rotates together with the crankshaft 41, and a detection element that is fixed to the body frame 11 and detects the rotation of the detected element. The detection element can detect the detected element mechanically, optically, or magnetically.

[0049] The motor rotation sensor 65 detects the rotation of the motor 3. The motor rotation sensor 65 may be configured to detect the rotation of a rotor of the motor 3, or may be configured to detect the rotation based on the current, voltage, or other electrical signals of the motor 3.

[0050] The transmission mechanism for the auxiliary force from the motor 3 is not limited to the above example. For example, the drive unit 40 may have an output shaft that extends in the left-right direction from inside the housing 51 to the outside. In this case, the rotation of the motor 3 is transmitted to the output shaft by the transmission mechanism. An auxiliary sprocket is attached to the output shaft outside the housing 51. The auxiliary sprocket is wound around the chain 46. The rotational force generated by the operation of the motor 3 rotates the auxiliary sprocket, which in turn rotates the rear wheel 22 in the forward direction via the chain 46.

[0051] <Configuration example of a motor control device> Fig. 3 is a diagram showing an example of the configuration of the motor control device 4. In the example shown in Fig. 3, the motor control device 4 includes a motor control unit (motor controller) 5 and a sharp curve running detection unit 6. The motor control unit 5 controls the assist force of the motor 3 in accordance with at least the pedaling force T detected by a torque sensor 62. The sharp curve running detection unit 6 detects, based on information obtained from a body motion sensor 63, that the electrically assisted bicycle 10 is running around a sharp curve with the body tilted at a predetermined angle or more from an upright state.

[0052] One example of the motor control device 4 is an MCU (Motor Control Unit). The motor control device 4 includes, for example, a processor, a memory, a motor drive circuit, and a motor monitoring unit. The processor can implement the functions of the motor control unit 5 and the sharp curve detection unit 6 by executing a program in the memory. Note that at least some of the functions of the motor control unit 5 and the sharp curve detection unit 6 may be implemented by a circuit other than the processor.

[0053] To realize the functions of the motor control unit 5, the processor inputs the pedaling force T and outputs a control signal for the motor 3. The motor drive circuit operates in accordance with the control signal to drive the motor 3. The motor drive circuit is, for example, an inverter. Power is supplied from the battery unit 35 to the motor 3 in response to the control signal from the processor. The motor 3 supplied with power rotates and generates a drive auxiliary output controlled by the motor control unit 5.

[0054] The motor monitoring unit detects values ​​related to the driving of the motor 3, such as the current, voltage, number of rotations, and rotation speed of the motor 3. The processor or the motor driving circuit may execute processing or operate using the values ​​detected by the motor monitoring unit. The motor monitoring unit can obtain a value indicating the rotation of the motor, such as the number of rotations or the rotation speed of the motor, from the motor rotation sensor 65.

[0055] The vehicle speed sensor 61 detects the rotation angle of the front wheel 21 (or other rotating body) and outputs a signal according to the rotation angle to the motor control device 4. For example, the vehicle speed sensor 61 detects the rotation of the front wheel 21 at every predetermined angle and outputs a square wave signal or a sine wave signal. The processor calculates the rotation speed of the front wheel 21 from the output signal of the vehicle speed sensor 61. Note that the vehicle speed sensor 61 may be configured to calculate the rotation speed.

[0056] The torque sensor 62 outputs a voltage signal having an amplitude corresponding to the magnitude of the detected torque. The torque sensor 62 may have a torque calculation circuit that converts the voltage signal into a torque value. The torque calculation circuit converts the output analog voltage signal into a digital value by, for example, AD conversion. The detected torque magnitude is output to the outside as a digital signal. Note that the motor control device 4 may be configured to receive the analog signal from the torque sensor 62 and convert it into a digital value.

[0057] The vehicle body motion sensor 63 outputs a value or signal indicating a change in the attitude of the vehicle body (i.e., the vehicle body frame). The vehicle body motion sensor 63 outputs at least two angles or angular velocities, for example, the yaw angle, roll angle, and pitch angle of the vehicle body. When the vehicle body motion sensor 63 is a six-axis sensor, the vehicle body motion sensor 63 outputs the yaw angular velocity, roll angular velocity, and pitch angular velocity of the vehicle body, as well as the acceleration in the front-rear direction, the acceleration in the left-right direction, and the acceleration in the up-down direction of the vehicle body. The vehicle body motion sensor 63 may have a circuit that calculates the yaw angular velocity, roll angular velocity, and pitch angular velocity, or angles thereof, from the detected electrical signal. Alternatively, the motor control device 4 may be configured to receive a value or signal from the vehicle body motion sensor 63 and convert it into the yaw angular velocity, roll angular velocity, and pitch angular velocity, or angles thereof.

[0058] <Example of operation> Fig. 4 is a flowchart showing an example of the operation of the motor control device 4 shown in Fig. 3. The motor control device 4 can periodically and repeatedly execute the process shown in Fig. 4. In Fig. 4, the motor control device 4 acquires the pedaling force T detected by the torque sensor 62 (S11). The motor control device 4 acquires the inclination angle or the angular velocity of the vehicle body detected by the vehicle body motion sensor 63 (S12).

[0059] The sharp curve detection unit 6 uses the body tilt angle or its angular velocity acquired in S12 to determine whether the electrically assisted bicycle 10 is traveling around a sharp curve with the body tilted at a predetermined angle to the left or right from an upright state (S13). In other words, the sharp curve detection unit 6 detects that the electrically assisted bicycle 10 is turning a sharp curve and that the body is tilted at a predetermined angle to the left or right from an upright state while turning. At least two of the (yaw angle or yaw angular velocity), (roll angle or roll angular velocity), and (pitch angle or pitch angular velocity) obtained from the body motion sensor 63 are used for the determination in S13.

[0060] The sharp curve detection unit 6 can execute the determination in S13 using, for example, two angles or angular velocities of yaw, roll, and pitch. That is, the angle or angular velocity of any combination of yaw and roll, roll and pitch, or yaw and pitch can be used in the determination in S13. The two values ​​in each combination may be any of an angle and an angle, an angular velocity and an angular velocity, or an angle and an angular velocity.

[0061] If it is determined in S13 that the vehicle is traveling around a sharp curve with the vehicle body tilted left or right by a predetermined angle or more (yes in S14), the motor control unit 5 controls the motor 3 to generate an auxiliary force that corresponds to the pedal force T and is adjusted for traveling around a sharp curve. If it is determined that the vehicle is not traveling around a sharp curve with the vehicle body tilted left or right by a predetermined angle or more (no in S14), the motor control unit 5 controls the motor 3 to generate an auxiliary force that corresponds to the pedal force T and is a normal auxiliary force that is not adjusted for traveling around a sharp curve.

[0062] In S13, the sharp curve detection unit 6 can determine whether the vehicle is traveling on a curve that is sharp enough to allow adjustment of the assist force to improve the assist feeling. When the sharp curve detection unit 6 detects that the vehicle is traveling on a sharp curve, the motor control unit 5 can adjust the assist force of the motor 3 for a sharp curve. Therefore, by adjusting the assist force for a sharp curve, the assist feeling of the occupant on the curve can be improved.

[0063] <Example of sharp curve detection processing> Fig. 5 is a flow chart showing an example of the processing of S12 and S13 shown in Fig. 4. In the example shown in Fig. 5, in S12, the motor control device 4 acquires the yaw angular velocity and the pitch angular velocity from the body motion sensor 63. If the absolute value of the yaw angular velocity is equal to or greater than a threshold value Th1 (first threshold value) (yes in S131) ​​and the pitch angular velocity is equal to or greater than a threshold value Th2 (second threshold value) (yes in S132), the sharp curve traveling detection unit 6 determines that the electric-assisted bicycle 10 is traveling on a sharp curve with the body tilted in the left-right direction by a predetermined angle or more (S133). If the absolute value of the yaw angular velocity is smaller than the threshold value Th1 (no in S131) ​​or if the pitch angular velocity is smaller than the threshold value Th2 (no in S132), it is determined that the electric-assisted bicycle 10 is not traveling on a sharp curve with the body tilted in the left-right direction by a predetermined angle or more (S134, S135).

[0064] In the example of Fig. 5, the yaw angular velocity and pitch angular velocity are used in the judgment in S13. In this way, when a combination of yaw and pitch is used, the yaw angular velocity (or angle) can be used to judge whether or not the vehicle is traveling around a curve, and the pitch angular velocity (or angle) can be used to judge whether or not the vehicle body is tilted. The inventors discovered that when an electrically assisted bicycle travels around a curve with the body tilted to a certain extent in the roll direction from an upright state, the pitch angle changes characteristically. Therefore, by using the pitch angular velocity or pitch angle, it is possible to efficiently and accurately detect whether the electrically assisted bicycle is traveling around a sharp curve with the body tilted to the left or right by more than a predetermined angle.

[0065] When yaw and pitch are used for the judgment, curve travel can be judged by the yaw angle or yaw angular velocity, and a sharp curve travel with the vehicle body tilted to the left or right by a predetermined angle or more can be judged by the pitch angle or pitch angular velocity. When yaw and roll are used for the judgment, curve travel can be judged by the yaw angle or yaw angular velocity, and a sharp curve travel with the vehicle body tilted to the left or right by a predetermined angle or more can be judged by the roll angle or roll angular velocity. When pitch and roll are used for the judgment, curve travel can be judged based on changes in the roll angle or roll angular velocity, and a sharp curve travel with the vehicle body tilted can be judged by the pitch angle or pitch angular velocity.

[0066] Fig. 6 is a diagram showing an example of time variations in yaw angular velocity, roll angular velocity, and pitch angular velocity during a period including a period in which the electrically assisted bicycle travels straight and a period in which the body is tilted left or right by a predetermined angle or more while traveling around a sharp curve. In the graph of Fig. 6, during the period in which the bicycle is traveling around a sharp curve, the absolute value of the yaw angular velocity in the turning direction increases. The roll angular velocity swings in the turning direction, then returns to 0, and swings in the opposite direction. The pitch angular velocity increases in the direction in which the front of the body faces upward.

[0067] The pitch angular velocity has a tendency to increase in the direction in which the front of the body faces upward when the vehicle is traveling around a sharp curve, whether turning right or left. Based on this tendency, for example, when the yaw angular velocity (or yaw angle) is equal to or greater than a first threshold value and the pitch angular velocity (or pitch angle) is equal to or greater than a second threshold value, it can be determined that the electrically assisted bicycle is traveling around a sharp curve with the body tilted to the left or right by a predetermined angle or more. In this way, by making a determination using a combination of yaw and pitch, it is possible to detect traveling around a curve in a state where adjustment of the assist force of the motor 3 is easily effective.

[0068] During a sharp curve, the roll angular velocity first swings in the turning direction and then swings in the opposite direction. Based on this tendency, for example, when the pitch angular velocity is equal to or greater than a threshold during the period in which the roll angular velocity swings in this manner, it is possible to detect a sharp curve with the vehicle body tilted left or right by a predetermined angle or more. Also, when the yaw angular velocity (or yaw angle) is equal to a first threshold and the roll angular velocity (or roll angle) is equal to or greater than a third threshold, it is possible to detect a sharp curve with the vehicle body tilted left or right by a predetermined angle or more.

[0069] Fig. 7 is a graph showing an example of time-dependent changes in yaw angular velocity, pitch angular velocity, and sharp curve detection results by the sharp curve detection unit 6. The sharp curve detection graph shows that, when the signal is at a high level, a sharp curve is detected in an inclined state where the vehicle body is inclined to the left or right by a predetermined angle or more. In the example shown in Fig. 7, a sharp curve is detected in an inclined state when the absolute value of the yaw angular velocity is equal to or greater than a threshold value Th1 and the pitch angular velocity is equal to or greater than a threshold value Th2.

[0070] FIG. 8 is a diagram plotting the trajectory of the route traveled by the electrically assisted bicycle 10. In FIG. 8, positions where the sharp curve detection unit 6 detects that the bicycle is traveling around a sharp curve in an inclined state, with the body tilted left or right by a predetermined angle or more, are plotted as black circles, and positions where the detection is not made as white circles. In this manner, the sharp curve detection unit 6 detects that the electrically assisted bicycle 10 is traveling around a sharp curve in an inclined state. As shown in FIG. 8, the sharp curve detection unit 6 detects that the bicycle is traveling around a sharp curve at a point where the radius of curvature of the travel trajectory is relatively small. When a sharp curve in an inclined state is detected in this manner, for example, the following control of the assist force of the motor 3 for sharp curves is performed.

[0071] <Example of assist force control process for sharp curves> The motor control unit 5 controls the assist force of the motor 3 according to the detection result of the sharp curve detection unit 6. When the sharp curve detection unit 6 detects that the electrically assisted bicycle 10 is traveling around a sharp curve in an inclined state with the body tilted to the left or right at a predetermined angle or more, the motor control unit 5 can adjust the assist force of the motor 3 according to the pedaling force for a sharp curve. For example, when the sharp curve detection unit 6 detects that the electric assisted bicycle 10 is traveling around a sharp curve in an inclined state, the motor control unit 5 can control the assist force differently from when a sharp curve is not detected.

[0072] As an example, when driving around a sharp curve in an inclined state is detected, the motor control unit 5 can change at least one of the assist ratio, assist responsiveness, assist magnitude, assist output waveform, and driving mode (assist mode) used to determine the assist force of the motor 3 to a value suitable for a sharp curve.

[0073] The assist ratio is the ratio of the assist force of the motor 3 to the pedaling force. The assist responsiveness is the responsiveness (follow-up) of the change in the assist force of the motor 3 to the change in the pedaling force. The motor control unit 5 can change the assist responsiveness, for example, by changing the speed at which the assist force is changed.

[0074] The magnitude of the assist may be, for example, the maximum assist force output by the motor 3. The assist output waveform is the waveform of the assist force output by the motor 3. For example, the assist output waveform can be changed by changing the assist ratio and the assist responsiveness.

[0075] The driving mode is an assist control mode that controls the assist force by setting a predetermined method for determining the assist force according to the pedal force. In each driving mode, a method for determining the assist force according to conditions such as the pedal force and vehicle speed is defined. By switching the driving mode, the method for determining the assist force according to the pedal force and other conditions can be changed. For example, when the sharp curve driving detection unit 6 detects that the vehicle is traveling around a sharp curve, the motor control unit 5 may switch the driving mode to a mode for traveling around a sharp curve.

[0076] In this way, when a sharp curve is detected, the motor control unit 5 can change the method of determining the assist force of the motor 3 in response to the pedal force to a sharp curve. In this case, the method of determining the assist force according to conditions including other elements such as the vehicle speed or crank rotation in addition to the pedal force may be changed to a sharp curve.

[0077] As an example, when the sharp curve detection unit 6 detects that the bicycle is turning a sharp curve in an inclined state, the motor control unit 5 can control the motor 3 so that the assisting force of the motor 3 according to the pedaling force is smaller than when the sharp curve is not detected. For example, the inventors have found that when the electrically assisted bicycle 10 turns a sharp curve with the body tilted to the left or right by a predetermined angle or more, the rider may feel a strong assist. When the rider feels a strong assist on a curve, he or she may feel that the curve's driving line is slightly deviated from the rider's intended line. In such a case, the rider's feeling of assistance can be improved by controlling the motor 3 so that the assisting force according to the pedaling force is smaller when the bicycle is turning a sharp curve in an inclined state than when the bicycle is going straight.

[0078] As another example, the motor control unit 5 may control the motor 3 so that when the sharp curve detection unit 6 detects a sharp curve in which the body is tilted to the left or right by a predetermined angle or more, the motor control unit 5 controls the motor 3 so that the auxiliary force of the motor 3 according to the pedaling force is larger than when the sharp curve is not detected. For example, when the function of automatically switching the driving mode according to the pedaling force is used, if the rider does not apply pedaling force and the electric-assisted bicycle coasts around a curve, the mode may switch to a driving mode with a low auxiliary force according to the pedaling force, and the auxiliary force may become weak. When the electric-assisted bicycle runs around a sharp curve with the body tilted to the left or right by a predetermined angle or more, it tends to be difficult to apply pedaling force. In such a case, after the sharp curve with the body tilted is detected, the motor 3 is controlled so that the auxiliary force according to the pedaling force is larger than when going straight, thereby ensuring the auxiliary force according to the pedaling force during or after the curve. As a result, the rider's feeling of assistance can be improved.

[0079] <Example of sharp curve detection processing taking vehicle speed into account> The sharp curve detection unit 6 may determine whether the electric-assisted bicycle 10 is making a sharp turn by using the vehicle speed in the traveling direction of the electric-assisted bicycle 10 detected by the vehicle speed sensor 61. For example, the sharp curve detection unit 6 may change a threshold value used to determine whether the electric-assisted bicycle 10 is making a sharp turn by tilting the vehicle body to the left or right by a predetermined angle or more, depending on the vehicle speed, using the yaw, roll, and pitch angles or angular velocities. For example, the sharp curve detection unit 6 detects whether the electric-assisted bicycle 10 is making a sharp turn by tilting the vehicle body to the left or right by a predetermined angle or more when the yaw angle or yaw angular velocity is equal to or greater than a first threshold value and the pitch angle or pitch angular velocity is equal to or greater than a second threshold value. In this case, at least one of the first threshold value and the second threshold value may be a value that changes depending on the vehicle speed of the electric-assisted bicycle. In addition, when determining whether the electric-assisted bicycle 10 is making a sharp turn based on a comparison between the roll angle or roll angular velocity and a third threshold value, the third threshold value may be a value that changes depending on the vehicle speed. Even if the curve radius is the same, if the vehicle speed is different, the inclination angle in the left or right direction of the vehicle body when making a curve changes. Therefore, by changing the threshold value depending on the vehicle speed, it is possible to detect whether the electric-assisted bicycle 10 is making a sharp turn by taking into account the difference in the degree of inclination due to the vehicle speed.

[0080] For example, the threshold value used by the sharp curve detection unit 6 to compare with at least one of the angles of yaw, roll, and pitch or the acceleration may be set to be larger as the vehicle speed increases. In other words, the higher the vehicle speed, the larger the degree of inclination of the vehicle body for determining that the vehicle is inclined at a predetermined angle or more in the left / right direction is a sharp curve.

[0081] <Example of detecting the start and end of a sharp curve> The sharp curve detection unit 6 may detect the start and end of sharp curve travel in an inclined state with the body of the electrically assisted bicycle 10 tilted left or right by a predetermined angle or more. The motor control unit 5 may determine a period for controlling the assist force of the motor 3 for sharp curves when sharp curve travel is detected, based on at least one of the detected start and end of sharp curve travel. This allows the motor control unit 5 to control the assist force according to the pedaling force in a period based on at least one of the start and end of a sharp curve with the body of the electrically assisted bicycle 10 tilted left or right by a predetermined angle or more, differently from the control in other adjacent periods.

[0082] The motor control unit 5 may control the assist force for a sharp curve, for example, during the period from the start to the end of detection of traveling around a sharp curve in an inclined state. In this case, the control of the assist force according to the pedaling force during the period from the start to the end of detection can be made different from the control during other adjacent periods.

[0083] The motor control unit 5 may continue to control the assist force for a sharp curve for a predetermined period even after the end of detection. In this case, the control of the assist force according to the pedaling force can be made different for a predetermined period after the end of the sharp curve is detected. For example, the motor control unit 5 can make the control of the assist force according to the pedaling force different from that for other adjacent periods during the period from the time when the end of the sharp curve is detected until a predetermined time has elapsed. In this case, the predetermined time may be a fixed time determined in advance, or may be determined based on a value indicating a traveling state such as the vehicle speed.

[0084] As an example, the motor control unit 5 may control the motor 3 so that the assist force according to the pedaling force is greater during a period from when the sharp curve traveling detection unit 6 detects the end of the sharp curve until a certain time has elapsed than during the previous period. This makes it possible to increase the assist force according to the pedaling force after the sharp curve has been passed. For example, in a curve, the vehicle may switch to a driving mode in which the assist force according to the pedaling force is low so that the occupant does not exert a pedaling force. In this case, by controlling the motor 3 so that the assist force according to the pedaling force is greater during a certain period after the end of the sharp curve traveling is detected, it is possible to ensure the assist force according to the pedaling force after the curve has been passed. As a result, the occupant's feeling of assistance can be improved.

[0085] <Other Modifications> 1, the crankshaft 41 passes through the drive unit 40, but the crankshaft 41 may not pass through the drive unit 40. For example, the drive unit 40 may be disposed around the axle 29 of the rear wheel 22 or around the axle 27 of the front wheel 21.

[0086] In the above example, the vehicle speed sensor 61 is configured to detect the rotation of a rotating body that rotates as the electric assisted bicycle travels. The vehicle speed sensor 61 is not limited to this. For example, an acceleration sensor that detects acceleration in the traveling direction of the electric assisted bicycle 10 (the front-rear direction of the body frame 11) may be used as the vehicle speed sensor 61.

[0087] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and the above-mentioned embodiment can be appropriately modified and carried out without departing from the spirit of the present invention. [Explanation of symbols]

[0088] 3: motor, 4: motor control device, 5: motor control unit, 6: sharp curve driving detection unit, 61: vehicle speed sensor, 62: torque sensor, 63: vehicle body motion sensor

Claims

1. a body motion sensor that detects a change in the posture of the body of the electrically assisted bicycle relative to a road surface; a torque sensor that detects a pedaling force of a pedal connected to a crankshaft of the electric assisted bicycle; A motor that generates an assist force to assist the pedal force; a motor control unit that controls the assist force of the motor in response to the pedaling force; a sharp curve detection unit that detects, based on information obtained from the vehicle body motion sensor, that the electrically assisted bicycle is traveling around a sharp curve in an inclined state where the vehicle body is inclined to the left or right at a predetermined angle or more from an upright state; The motor control unit controls the assist force in response to a detection result of the sharp curve running detection unit, The sharp curve detection unit detects when the electrically assisted bicycle is traveling around a sharp curve in an inclined state in which the body is tilted to the left or right at a predetermined angle or more from an upright position so that the pitch angular velocity in the direction in which the front of the body faces upward and the rear of the body faces downward increases.

2. a body motion sensor that detects a change in the posture of the body of the electrically assisted bicycle relative to a road surface; a torque sensor that detects a pedaling force of a pedal connected to a crankshaft of the electric assisted bicycle; A motor that generates an assist force to assist the pedal force; a motor control unit that controls the assist force of the motor in response to the pedaling force; a sharp curve detection unit that detects, based on information obtained from the vehicle body motion sensor, that the electrically assisted bicycle is traveling around a sharp curve in an inclined state where the vehicle body is inclined to the left or right at a predetermined angle or more from an upright state; The motor control unit controls the assist force in response to a detection result of the sharp curve running detection unit, The sharp curve detection unit detects that the electrically assisted bicycle is traveling around a sharp curve in a leaned state based on the (yaw angle or yaw angular velocity) and (pitch angle or pitch angular velocity), or based on the (roll angle or roll angular velocity) and (pitch angle or pitch angular velocity), of the electrically assisted bicycle obtained from the body movement sensor.

3. a body motion sensor that detects a change in the posture of the body of the electrically assisted bicycle relative to a road surface; a torque sensor that detects a pedaling force of a pedal connected to a crankshaft of the electric assisted bicycle; A motor that generates an assist force to assist the pedal force; a motor control unit that controls the assist force of the motor in response to the pedaling force; a sharp curve detection unit that detects, based on information obtained from the vehicle body motion sensor, that the electrically assisted bicycle is traveling around a sharp curve in an inclined state where the vehicle body is inclined to the left or right at a predetermined angle or more from an upright state; The motor control unit controls the assist force in response to a detection result of the sharp curve running detection unit, The sharp curve detection unit detects that the electrically assisted bicycle is traveling around a sharp curve in the leaned state when the yaw angle or yaw angular velocity of the electrically assisted bicycle is equal to or greater than a first threshold value, and when the pitch angle or pitch angular velocity of the electrically assisted bicycle is equal to or greater than a second threshold value.

4. The electrically assisted bicycle according to claim 3, An electrically assisted bicycle, wherein at least one of the first threshold value and the second threshold value varies depending on the vehicle speed of the electrically assisted bicycle.

5. An electrically assisted bicycle according to any one of claims 1 to 4, The motor control unit controls the assist force according to the pedaling force differently depending on whether it is detected that the electrically assisted bicycle is traveling around a sharp curve in the leaning state or not.

6. The electrically assisted bicycle according to claim 5, The motor control unit, when it is detected that the electrically assisted bicycle is traveling around a sharp curve in the leaning state, controls the motor so that the assist force corresponding to the pedaling force is smaller than when it is not detected.

7. An electrically assisted bicycle according to any one of claims 1 to 6, the sharp curve travel detection unit detects a start and an end of travel of the electrically assisted bicycle around a sharp curve in the leaning state; The motor control unit changes the control of the assist force according to the pedaling force in a period based on at least one of the start and end of the electrically assisted bicycle making a sharp curve in the leaning state.

8. The electrically assisted bicycle according to claim 7, The motor control unit changes the control of the assist force according to the pedaling force for a predetermined period of time after the electrically assisted bicycle has finished traveling around a sharp curve in the leaning state.

9. A motor control device that controls a motor that generates an assisting force to assist the pedal force of an electric assisted bicycle, a motor control unit that controls the assist force of the motor in response to a pedal force detected by a torque sensor that detects the pedal force; a sharp curve detection unit that detects when the electrically assisted bicycle is traveling around a sharp curve with the body tilted at a predetermined angle or more in the left or right direction from an upright state, based on information obtained from a body motion sensor that detects changes in the posture of the body of the electrically assisted bicycle relative to the road surface, The motor control unit controls the assist force in response to a detection result of the sharp curve running detection unit, The motor control device, wherein the sharp curve detection unit detects when the electric assisted bicycle is traveling around a sharp curve in an inclined state in which the body is tilted to the left or right at a predetermined angle or more from an upright position so that the pitch angular velocity in the direction in which the front of the body faces upward and the rear of the body faces downward increases.

10. A motor control device that controls a motor that generates an auxiliary force to supplement the pedal force of an electric assisted bicycle, a motor control unit that controls the assist force of the motor in response to a pedal force detected by a torque sensor that detects the pedal force; a sharp curve detection unit that detects when the electrically assisted bicycle is traveling around a sharp curve with the body tilted at a predetermined angle or more in the left or right direction from an upright state, based on information obtained from a body motion sensor that detects changes in the posture of the body of the electrically assisted bicycle relative to the road surface, The motor control unit controls the assist force in response to a detection result of the sharp curve running detection unit, The sharp curve detection unit detects that the electric assisted bicycle is traveling around a sharp curve in the leaned state based on the (yaw angle or yaw angular velocity) and (pitch angle or pitch angular velocity), or based on the (roll angle or roll angular velocity) and (pitch angle or pitch angular velocity), of the electric assisted bicycle obtained from the body movement sensor.

Images