JP3081523B2 - Bicycle with electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle with an electric motor which assists a driving force by a human power by connecting an electric motor to a bicycle mechanism which can be driven by a human power.

[0002]

2. Description of the Related Art FIGS. 13 and 14 show a configuration of a control system of a conventional bicycle with an electric motor. The manual torque generated by depressing the pedal is detected by a torque detection mechanism (5), and the detection signal is transmitted to a motor torque adjustment circuit (6).
Sent to According to this, the motor torque adjustment circuit (6)
Then, a motor torque command corresponding to the input torque detection signal is created and supplied to the electric motor (2). As a result, in addition to the human-powered torque, the motor output torque having a magnitude corresponding to the human-powered torque value is supplied to the bicycle mechanism (1),
The driving force by human power is assisted. As the torque detecting mechanism (5), for example, a method of connecting a planetary gear mechanism to an output shaft of an electric motor to detect torque between gears (for example, Japanese Patent Laid-Open No. 5-58379), or a method for detecting torque between a pedal and a sprocket There is known a method of detecting the torsion bar by twisting (for example, JP-A-4-321482).

[0003]

However, since the structure of the torque detecting mechanism is generally complicated, the structure of the entire bicycle with the electric motor is complicated, and there is a problem that the weight is increased. An object of the present invention is to provide a bicycle with an electric motor having a simple configuration capable of generating a motor output torque according to human power torque without using a torque detection mechanism.

[0004]

In the bicycle with an electric motor according to the present invention, an electric motor is connected to a bicycle mechanism which can be driven by human power, and a signal corresponding to a wheel rotation angle or a rotation angular velocity of the bicycle mechanism is detected. And a control circuit for controlling the output torque of the electric motor based on the sensor detection signal.

The above-mentioned control circuit is based on an inverse function of a bicycle mechanism transfer function in which a human power and a torque given to the bicycle mechanism by an electric motor are used as an input signal, and a signal corresponding to a wheel rotation angle or a rotation angular velocity is an output signal. A first arithmetic processing unit for deriving an input torque value for the bicycle mechanism from the sensor detection signal; and a second operation unit for deriving a manual torque value by subtracting an output torque value of the electric motor from the derived input torque value for the bicycle mechanism. It has arithmetic processing means and motor torque adjusting means for creating a motor torque command according to the derived manual torque value and supplying it to the electric motor.

In the bicycle with an electric motor according to the present invention, human power and torque from the electric motor are input to the bicycle mechanism, and a signal corresponding to a wheel rotation angle or a rotation angular velocity of the bicycle mechanism is detected by a sensor. The sensor detection signal is input to a first arithmetic processing unit. Here, since the first arithmetic processing means has an inverse function of the bicycle mechanism transfer function as its transfer function, the input / output relationship with the bicycle mechanism transfer function is reversed, and the wheel rotation angle or the rotation angular velocity is reduced. By inputting the corresponding sensor detection signal (output value of the bicycle mechanism transfer function), the input torque value to the bicycle mechanism, that is, the total value of the torque component by the human power and the torque component by the electric motor (the input value of the bicycle mechanism transfer function) ) Will be derived. The input torque value for the bicycle mechanism derived in this way is input to the second arithmetic processing means,
By subtracting the torque component from the electric motor (output torque value of the electric motor), the torque component due to human power
(Manual torque value) is derived. Therefore, a manual torque value can be obtained without using a torque detection mechanism.
The manual torque value derived in this way is input to the motor torque adjusting means, and a motor torque command corresponding to the manual torque value is created and supplied to the electric motor. As a result, the electric motor generates a motor output torque corresponding to the manual torque.

Specifically, the bicycle mechanism transfer function includes a subtraction processing unit that takes a human power and a torque from an electric motor as input signals, and subtracts a loss torque value from the input signal, and outputs the inertia force of the bicycle mechanism and the subtraction result to the subtraction result. And a transfer function unit for performing an operation process using a transfer function using the viscous resistance as a parameter to derive a rotational angular velocity.

In this specific configuration, the manpower and the torque from the electric motor are input to the subtraction processing unit, and the drive torque value of the bicycle mechanism that actually contributes to the running of the bicycle is calculated by subtracting the loss torque value. You. The calculated driving torque value of the bicycle mechanism is input to the transfer function unit. Here, the relationship between the driving torque of the bicycle mechanism and the wheel rotational angular velocity can be defined by using the inertial force and the viscous resistance of the bicycle mechanism as parameters. Accordingly, a wheel rotation angular velocity in actual bicycle running is derived from the calculated drive torque value by a transfer function unit having this relationship as a transfer function.

[0009] More specifically, a second transfer function section that derives a first loss torque component due to air resistance received during running of the bicycle based on the derived wheel rotational angular velocity is provided downstream of the transfer function section. And the first loss torque component is input to the subtraction processing unit as the loss torque value.

Here, since the air resistance during bicycle running is considered to be proportional to the square of the bicycle running speed, the second transfer function section performs a square operation on the wheel rotation angle and multiplies it by an appropriate coefficient. , A first loss torque component due to air resistance can be derived. by this,
The air resistance received when the bicycle runs is incorporated into the bicycle mechanism transfer function.

More specifically, an addition processing unit for adding a second loss torque component due to disturbance random noise to a first loss torque component due to the air resistance is provided between the second transfer function unit and the subtraction processing unit. The result of the addition is input to the subtraction processing unit as the loss torque value.

In the specific configuration, the second processing unit adds the second loss torque component due to the random disturbance noise to the first loss torque component received when the bicycle is running.
As a result, in addition to the air resistance received when riding a bicycle,
Disturbance random noise will be incorporated into the bicycle mechanism transfer function.

More specifically, a noise removing means for removing a high-frequency component having a frequency higher than the rotation frequency of the pedal is provided at a stage subsequent to the first arithmetic processing means.

If the disturbance random noise is not incorporated in the bicycle mechanism transfer function, an output signal including a second torque loss component due to the disturbance random noise is derived from the first arithmetic processing means. Here, generally, the frequency of the second loss torque component due to disturbance random noise is sufficiently higher than the rotation frequency of the pedal. Therefore, by removing the high frequency component from the output signal of the first arithmetic processing means by the noise removing means, the second loss torque component due to disturbance random noise can be subtracted from the output signal. The total value of the torque component and the torque component by the electric motor (input torque value for the bicycle mechanism transfer function) is derived.

More specifically, third arithmetic processing means having a transfer function for stabilizing the operation of the control circuit is interposed between the second arithmetic processing means and the motor torque adjusting means. Therefore, even when the control circuit has a configuration that is unstable due to disturbance, the operation of the control circuit is stable, and an appropriate human torque value is always calculated.

In another configuration of the bicycle with an electric motor according to the present invention, the control circuit uses, as an input signal to the bicycle mechanism, a torque value obtained by subtracting a load torque from a human power and a driving torque by the electric motor, and outputs a wheel rotation angle or a rotation angular velocity. A first arithmetic processing means for deriving an input torque value for the bicycle mechanism from the sensor detection signal based on an inverse function of a bicycle mechanism transfer function having a signal corresponding to the output signal, and an input torque for the derived bicycle mechanism. Second arithmetic processing means for subtracting the output torque value of the electric motor from the value to derive the observed torque value, and based on a minimum value appearing in a half cycle of the pedal rotation in the variation of the derived observed torque value. The load torque value for the bicycle mechanism is estimated, the load torque value is added to the observed torque value, and the load torque value is given to the bicycle mechanism. A third arithmetic processing means for deriving the human power torque value, to create a motor torque command corresponding to the derived human power torque value, which comprises a motor torque adjusting means for supplying to the electric motor.

In the bicycle with an electric motor according to the present invention, a torque value (τh + τm−τa) obtained by subtracting the load torque τa from the human power and the driving torque (τh + τm) by the electric motor is input to the bicycle mechanism, and the wheel rotation of the bicycle mechanism is performed. A signal corresponding to the angle or the rotational angular velocity is detected by the sensor.
The sensor detection signal is input to a first arithmetic processing unit. Here, since the first arithmetic processing means has an inverse function of the bicycle mechanism transfer function as its transfer function, the input / output relationship with the bicycle mechanism transfer function is reversed, and the wheel rotation angle or the rotation angular velocity is reduced. By inputting the corresponding sensor detection signal (output value of the bicycle mechanism transfer function), the input torque value to the bicycle mechanism, that is, the torque value (bicycle value obtained by subtracting the load torque τa from the driving torque (τh + τm) by the human power and the electric motor). The input value of the mechanism transfer function: τh + τm-τa) is derived. The input torque value for the bicycle mechanism derived in this manner is input to the second arithmetic processing means, and the torque component (output torque value of the electric motor) by the electric motor is subtracted to obtain the torque component (manpower) by human power. A torque value (observed torque value: τh-τa) obtained by subtracting the load torque component τa from the torque value τh) is derived.
The observed torque value is input to the third calculation processing means.

In the process of applying a manual torque to the bicycle mechanism by pedaling the bicycle pedal, the magnitude of the manual torque is determined by the relationship between the direction of the pedaling force applied to the pedal and the inclination angle of the crank arm. Becomes zero when it reaches the top dead center or the bottom dead center, and becomes the maximum value when the rotation angle of the pedal is 90 degrees. For this reason, a minimum value which becomes zero in a half cycle of the rotation cycle of the pedal appears in the fluctuation of the manual torque value. On the other hand, the load torque component applied to the bicycle mechanism is dominated by the load due to the wind pressure applied to the bicycle and the human body and the inclination of the road surface, so that the magnitude fluctuates in a cycle sufficiently longer than the rotation cycle of the pedal. Therefore, the load torque component τa
In the variation of the observed torque value (τh−τa) obtained by subtracting the minimum value, a minimum value appears in a half cycle of the rotation cycle of the pedal. At the time when the minimum value occurs, the human torque component τh is zero, so the minimum value of the observed torque value matches the value (−τa) obtained by inverting the sign of the load torque component τa.

Therefore, based on the minimum value of the periodically obtained observed torque value, a temporally continuous load torque value τa is estimated and added to the observed torque value (τh−τa). The torque value τh will be derived. Thus, a human-powered torque value can be obtained without using a torque detection mechanism. The manual torque value thus derived is input to the motor torque adjusting means,
A motor torque command corresponding to the manual torque value is created,
Supplied to the electric motor. As a result, the electric motor generates a motor output torque corresponding to the manual torque.

Specifically, the bicycle mechanism transfer function is a transfer function using the inertia force and the viscous resistance of the bicycle mechanism as parameters, and calculates a torque value obtained by subtracting a load torque from a driving torque by a human power and an electric motor. , And the rotational angular velocity is derived from the input signal.

Here, the input signal to the bicycle mechanism is
It is a driving torque value of the bicycle mechanism that actually contributes to the running of the bicycle, and the relationship between the driving torque of the bicycle mechanism and the wheel rotational angular velocity can be defined using the inertial force and the viscous resistance of the bicycle mechanism as parameters. Therefore, the wheel rotation angular velocity in actual bicycle running is derived from the input signal by a bicycle mechanism transfer function having this relationship as a transfer function.

Specifically, the bicycle mechanism transfer function is
A torque value obtained by subtracting the load torque from the driving torque by the human power and the electric motor is used as an input signal to the bicycle mechanism,
A subtraction processing unit for subtracting a load torque component due to air resistance received during cycling from the input signal; and performing a calculation process using a transfer function using the inertia force and the viscous resistance of the bicycle mechanism as parameters as a parameter to derive a rotational angular velocity. First
Based on a transfer function part and the derived rotational angular velocity,
And a second transfer function unit for deriving a load torque component due to air resistance received when the bicycle is running. The derived load torque component is input to the subtraction processing unit.

In the specific structure, a torque value obtained by subtracting the load torque from the driving torque by the human power and the electric motor is input to the subtraction processing unit, and the load torque component is subtracted, and the bicycle mechanism that actually contributes to the bicycle running is provided. Is calculated. The calculated driving torque value of the bicycle mechanism is input to the first transfer function unit. Here, the relationship between the driving torque of the bicycle mechanism and the wheel rotational angular velocity can be defined by using the inertial force and the viscous resistance of the bicycle mechanism as parameters. Therefore, the first transfer function unit using this relationship as a transfer function derives the wheel rotation angular velocity during actual bicycle running from the calculated drive torque value. or,
Since the air resistance during bicycle running is considered to be proportional to the square of the bicycle running speed, the second transfer function section performs a square operation on the wheel rotation angle and multiplies it by an appropriate coefficient to obtain the load torque due to the air resistance. The components can be derived. As a result, the air resistance received when the bicycle runs is incorporated into the bicycle mechanism transfer function.

More specifically, fourth arithmetic processing means having a transfer function for stabilizing the operation of the control circuit is interposed between the third arithmetic processing means and the motor torque adjusting means. . Therefore, even when the control circuit has a configuration that is unstable due to disturbance, the operation of the control circuit is stable, and an appropriate human torque value is always calculated.

[0025]

According to the bicycle with the electric motor according to the present invention, since the torque detecting mechanism can be omitted, the structure of the entire bicycle with the electric motor can be simplified and the weight can be reduced. is there.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on four examples with reference to the drawings. First Embodiment The bicycle with an electric motor according to the present embodiment shown in FIG. 2 incorporates air resistance and disturbance random noise received during running of a bicycle into a bicycle mechanism transfer function.

FIG. 1 shows the entire structure of a bicycle with an electric motor according to the present embodiment. The wheels of a bicycle mechanism (1) which can be driven by human power have an electric motor (2) which assists the driving power by human power. Are connected, and a rotation angle sensor (3) for detecting the rotation angle of the wheel is attached. Further, a power assist controller (4) for controlling the output torque of the electric motor based on a wheel rotation angle detection signal obtained from the rotation angle sensor (3) is provided. As the rotation angle sensor (3), for example, a sensor having a simple configuration such as a well-known rotary encoder can be adopted.

The human-power torque generated by depressing the pedal and the motor output torque generated by the electric motor (2) are given to the bicycle mechanism (1), whereby the wheels of the bicycle mechanism (1) are driven to rotate. . The wheel rotation angle is detected by a rotation angle sensor (3), and the rotation angle detection signal is input to a power assist controller (4). In response, the power assist controller (4)
Creates a motor torque command and supplies it to the electric motor (2). This drives the wheels.

FIG. 2 is a block diagram showing a control system of the bicycle with an electric motor according to the present embodiment. First, the power assist controller (4) will be specifically described, and then modeling of the bicycle mechanism (1) necessary for designing the power assist controller (4) will be described.

In FIG. 2, the human-powered torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor are simultaneously applied to the bicycle mechanism (1), and the wheels of the bicycle mechanism (1) are turned on. Driven. Then, the rotation angle θ of the wheel is detected by the rotation angle sensor (3), and a detection signal of the wheel rotation angle θ is input to the power assist controller (4).

In the power assist controller (4), the wheel rotation angle θ obtained from the rotation angle sensor (3)
Is input to the differential calculator (41), and the wheel rotational angular velocity ω is calculated. The calculated wheel rotational angular velocity ω is input to the inverse function calculator (42). Here, the inverse function calculator (42)
Is a bicycle mechanism transfer function Pn (s) from the input of the manual torque value τh and the motor output torque value τm to the derivation of the wheel rotational angular velocity ω in a model of the bicycle mechanism (1) described later.
And the inverse function Pn (s) ^-1 of
^-1 has an input / output relationship opposite to that of the bicycle mechanism transfer function Pn (s). Therefore, by inputting the wheel rotational angular velocity ω to the inverse function Pn (s) ⁻¹ , the manual torque value τh
And the sum of the motor output torque value τm (τh + τm). The sum (τh + τm) of the derived manpower torque value τh and the motor output torque value τm is input to the subtractor (43), and the manpower torque value τh is derived by subtracting the motor output torque value τm. . The derived manual torque value τh is input to the stabilization processing circuit (44).
Here, the stabilization processing circuit (44) has a transfer function Q (s) for stabilizing the operation of the control circuit. Is calculated. A well-known method is used to determine the transfer function Q (s).
(For example, Journal of the Robotics Society of Japan, Vol. 11, No. 4, May 1993
Month, see pages 6 to 13). The manual torque value τh ′ thus derived is input to the motor torque adjustment circuit (45), and a motor torque command corresponding to the manual torque value τh ′ is created and supplied to the electric motor (2). . Note that the adjustment gain of the motor torque adjustment circuit (45) can be defined by a constant value or an arbitrary function using the running speed of the bicycle as a parameter. As a result, the electric motor (2) generates a motor output torque corresponding to the human power torque generated by depressing the pedal.

Next, modeling of the bicycle mechanism (1) will be described. FIG. 3 shows a basic configuration of a model of the bicycle mechanism (1), and is a total value (τh + τm) of a manual torque value τh generated by depressing a pedal and a motor output torque value τm generated by an electric motor. Is input to the subtraction unit (11), and the drive torque value τ of the bicycle mechanism (1) that actually contributes to the bicycle running is calculated by subtracting the loss torque value τ1. The calculated drive torque value τ is input to the torque-angular velocity conversion unit (12). here,
The relationship between the driving torque value τ of the bicycle mechanism (1) and the wheel rotational angular velocity ω can be defined by using the inertia force J and the viscous resistance D of the bicycle mechanism (1) during running of the bicycle as parameters. (12) is the transfer function G of the following equation 1.
(s).

[0033]

## EQU1 ## G (s) = 1 / (Js + D)

Therefore, the torque-angular velocity converter (12) derives the wheel rotational angular velocity ω during actual bicycle running. The derived wheel rotational angular velocity ω is calculated by an integral operation unit (1
The wheel rotation angle θ is derived by inputting to 3) and performing integration.

FIG. 4 shows a specific structure of a model of the bicycle mechanism (1) in which the loss torque value τl is further taken as an element. The wheel rotational angular velocity ω derived by the torque-angular velocity conversion section (12) is input to the integral calculation section (13) and also to the square calculation section (14). here,
It is considered that the air resistance during cycling is proportional to the square of the cycling speed. Therefore, after squaring the wheel rotation angular velocity ω in the square calculation unit (14), the wind pressure torque calculation unit (15) multiplies the square value by a coefficient C1 according to the viscosity of the air, so that One loss torque component τe is derived. Derived first loss torque component τe
Is input to the addition unit (16), and the second loss torque component τd due to disturbance random noise is added to derive an accurate loss torque value τl received during running of the bicycle. The derived loss torque value τl is input to the subtraction unit (11). As described above, the bicycle mechanism (1) is modeled, the bicycle mechanism transfer function Pn (s) is derived, and the inverse function Pn (s) ^-1 is obtained by a well-known method to input the wheel rotational angular velocity ω. Input torque given to bicycle mechanism (1) by human power and electric motor as signal
The transfer function of the inverse system having (τh + τm) as the output signal is obtained.

FIG. 5 shows a control procedure of the power assist controller (4) of the present invention. When the bicycle starts to be driven by human power and motor output, first, in step S1, the motor output torque value τm is initialized to 0,
In step S2, a detection signal of the wheel rotation angle θ is fetched from the rotation angle sensor (3).

In step S3, the detected wheel rotation angle θ is input to the differential calculator (41) to calculate the wheel rotation angular speed ω. In step S4, the wheel rotation angular speed ω is determined to be positive. It is determined whether or not the answer is NO, and if NO, the process returns to step S1. YE in step S4
If determined to be S, the process proceeds to step S5, in which the wheel rotation angular velocity ω is input to the inverse function calculator (42).
The sum of the human input torque value τh and the motor output torque value τm (τh
+ Τm). Then, in step S6, the total value (τh + τm) of the manual torque value τh and the motor output torque value τm
Is input to the subtractor (43) to subtract the motor output torque value τm, thereby calculating the manual torque value τh. Then, in step S7, an appropriate manual torque value τh ′ for stabilizing the operation of the control circuit is calculated by inputting the manual torque value τh to the stabilization processing circuit (44). Next, in step S8, the manual torque value τh ′ is input to the motor torque adjustment circuit (45), thereby
Create motor torque command according to h '
It supplies to (2), and returns to step S2.

According to the above procedure, the output torque of the electric motor (2) can be changed according to the manual torque generated by depressing the pedal, whereby an appropriate auxiliary driving force can be obtained. For example, on an uphill, by depressing the pedal with a large force, the manpower torque input to the bicycle mechanism increases, and as a result, the motor output torque supplied to the bicycle mechanism by the electric motor increases, The driving force is reduced. On the other hand, on a downhill, since a large force is not required to depress the pedal, the manpower torque input to the bicycle mechanism is reduced, and as a result, the motor output torque supplied to the bicycle mechanism by the electric motor is reduced. Becomes smaller.

Second Embodiment In the first embodiment described above, the air resistance and disturbance random noise received when the bicycle is running are incorporated in the bicycle mechanism transfer function. On the other hand, with the electric motor of this embodiment shown in FIG. In a bicycle, only the air resistance received when the bicycle is running is incorporated in the bicycle mechanism transfer function, and the power assist controller (40) is provided with a low-pass filter circuit (47) to remove disturbance random noise. The overall configuration of the bicycle with an electric motor according to the present embodiment is the same as that of the first embodiment shown in FIG.

FIG. 6 is a block diagram showing a control system of the bicycle with an electric motor according to the present embodiment. As in the first embodiment, first, the power assist controller (40) will be specifically described, and thereafter, The modeling of the bicycle mechanism (1) will be described.

In FIG. 6, the human-powered torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor are simultaneously applied to the bicycle mechanism (1). Driven. Then, the rotation angle θ of the wheel is detected by the rotation angle sensor (3), and a detection signal of the wheel rotation angle θ is input to the power assist controller (40).

In the power assist controller (40), the wheel rotation angle θ obtained from the rotation angle sensor (3)
Is input to the differential calculator (41), and the wheel rotational angular velocity ω is calculated. The calculated wheel rotational angular velocity ω is input to the inverse function calculator (46). Here, the inverse function calculator (46)
In the model of the bicycle mechanism (1) described below, a torque value (τh + τm−τd) obtained by subtracting a loss torque component τd due to disturbance random noise from a total value of a human-power torque value τh and a motor output torque value τm as an input signal It has an inverse function Pn '(s) ^-1 of the bicycle mechanism transfer function Pn' (s) up to the derivation of the wheel rotational angular velocity ω. The inverse function Pn '(s) ^-1
Has an input / output relationship opposite to that of the bicycle mechanism transfer function Pn '(s). When the wheel rotation angular velocity ω is input to the inverse function Pn' (s) ^-1 , the input torque value ( τh +
τm−τd) will be derived.

The derived torque value (τh + τm-τd) is input to a low-pass filter circuit (47), and a frequency component higher than the rotation frequency of the pedal is removed. Here, generally, the frequency of the loss torque component τd due to disturbance random noise is sufficiently higher than the rotation frequency of the pedal. Therefore, from the low-pass filter circuit (47), a signal in which the loss torque component τd due to disturbance random noise is removed from the derived torque value (τh + τm−τd), that is, the signal of the human-power torque value τh and the motor output torque value τm Total value (τh + τm)
Is output.

The sum (τh + τm) of the derived manpower torque value τh and the motor output torque value τm is input to a subtractor (43), and the manpower torque value τh is reduced by subtracting the motor output torque value τm. Derived. Thereafter, the same processing as in the first embodiment is performed on the human torque value τh, and the electric motor (2) outputs a motor output torque corresponding to the human torque generated by depressing the pedal. become.

Next, modeling of the bicycle mechanism (1) will be described. As shown in FIG. 6, the total value (τh + τm) of the manual torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor is the first value.
The loss torque component τd due to disturbance random noise is input to the subtraction unit (17). The result of the subtraction is input to a second subtraction unit (18), and the driving torque value of the bicycle mechanism (1) that actually contributes to the cycling by subtracting the loss torque component τe due to the air resistance received during the cycling. τ is calculated. The calculated drive torque value τ is the torque −
It is input to the angular velocity converter (12). Here, the torque-angular velocity converter (12) is represented by the transfer function G (s) of the above equation 1, and the wheel rotational angular velocity ω in actual bicycle running is derived as in the first embodiment. . The derived wheel rotation angular velocity ω is input to the integration calculation unit (13), and is integrated to derive the wheel rotation angle θ. The derived wheel rotational angular velocity ω is also input to the square calculating section (14) at the same time, and after squaring the wheel rotational angular velocity ω, the wind pressure torque calculating section (15) calculates the square value according to the viscosity of the air. Coefficient C
By multiplying by 1, a torque loss component τe due to air resistance is derived. The derived loss torque component τe is input to the subtraction unit (18).

By modeling the bicycle mechanism (1) as described above, the torque value (τh + τm−τd) obtained by subtracting the loss torque component τd due to disturbance random noise from the total value of the manual torque value τh and the motor output torque value τm. ) Can be used as an input signal to obtain the bicycle mechanism transfer function Pn '(s) up to the derivation of the wheel rotational angular velocity ω. Then, by obtaining the inverse transfer function Pn '(s) ^-1 from the transfer function Pn' (s), the wheel rotation angular velocity ω is used as an input signal,
A transfer function of an inverse system using the input torque value (τh + τm−τd) as an output signal is obtained.

According to the bicycle with an electric motor according to the present embodiment, even when the inverse function calculator (46) does not incorporate a disturbance random noise elimination element, the disturbance random noise is controlled by the low-pass filter circuit (47). Τd can be removed. by this,
It is possible to obtain the manpower torque generated by actually depressing the pedal, and to provide a motor output torque corresponding to the manpower torque to the electric motor (2) to obtain an appropriate auxiliary driving force.

Third Embodiment A bicycle with an electric motor according to this embodiment shown in FIG. 7 has a power assist controller (8) and a human-powered torque value calculating circuit (82).
Is provided, a load torque value for the bicycle mechanism (1) is estimated, and a torque value given to the bicycle mechanism (1) by human power is derived based on the estimated value. The overall configuration of this embodiment is the same as that of the first embodiment shown in FIG.

FIG. 7 is a block diagram showing a control system of the bicycle with an electric motor according to the present embodiment. First, the power assist controller (8) will be specifically described, and then modeling of the bicycle mechanism (1) will be described.

In FIG. 7, the torque value (τh + τm) obtained by subtracting the load torque τa from the total value of the human output torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor, that is, the drive torque value. −τa)
Is input to the bicycle mechanism (1), and the wheels of the bicycle mechanism (1) are driven. Here, the load torque τa is given as a total value (τe + τs + τd) of a load torque component τe due to air resistance, a load torque component τs due to road surface inclination, and a load torque component τd due to disturbance random noise. Then, the rotation angle θ of the wheel is detected by the rotation angle sensor (3), and a detection signal of the wheel rotation angle θ is input to the power assist controller (8).

In the power assist controller (8), the wheel rotation angle θ obtained from the rotation angle sensor (3)
Is input to the differential calculator (41), and the wheel rotational angular velocity ω is calculated. The calculated wheel rotational angular velocity ω is input to the inverse function calculator (81). Here, the inverse function calculator (81)
In the model of the bicycle mechanism (1) described below, the input torque value (τh + τm−τa) is used as an input signal, and the bicycle mechanism transfer function Rn up to the derivation of the wheel rotational angular velocity ω is obtained.
It has the inverse function Rn (s) ^-1 of (s). Inverse function Rn (s) ^-1
Has an input / output relationship opposite to that of the bicycle mechanism transfer function Rn (s), and the input torque value (τh + τm) is input by inputting the wheel rotation angular velocity ω to the inverse function Rn (s) ^-1.
−τa) will be derived.

The derived torque value (τh + τm−τa) is input to a subtractor (43), and the observed torque value (τh−τa) is derived by subtracting the motor output torque value τm. The derived observed torque value (τh−τa) is input to the manual torque value calculation circuit (82).

Here, the operation principle of the manual torque value calculating circuit (82) will be specifically described. As shown by an arrow A in FIG. 9, when a pedaling force is applied vertically downward to one of the pedals (9a), the crank arm (90) rotates clockwise as shown by an arrow B. Here, the tilt angle (crank angle) of the crank arm (90) is set to 0 degrees when the one pedal (9a) reaches the top dead center, and is taken clockwise. At this time,
In the process of pedaling the bicycle, the magnitude of the human torque τh applied to the bicycle mechanism (1) is, as shown in FIG. 10, when one of the pedals (9a) reaches the top dead center or the bottom dead center, It becomes zero when the crank angle is 0 or 180 degrees, and becomes the maximum value when the crank angle is 90 or 270 degrees. For this reason, a minimum value that becomes zero in a half cycle of the pedal rotation cycle appears in the fluctuation of the human input torque τh.

On the other hand, the load torque τa is a total value (τe + τs + τd) of the load torque component τe due to the air resistance, the load torque component τs due to the inclination of the road surface, and the load torque component τd due to the disturbance random noise, as described above.
The load torque component τe due to the air resistance and the load torque component τs due to the inclination of the road surface are dominant. Therefore, the magnitude of the load torque τa fluctuates in a cycle sufficiently longer than the rotation cycle of the pedal.

For example, when the inclination of the road surface changes as shown in FIG. 8A, the load torque is substantially zero on a flat road surface,
On an uphill slope, a positive load torque is generated according to the slope, and on a downhill slope, a negative load torque is generated according to the slope. That is, the load torque τa varies in a cycle corresponding to the change in the slope of the road surface, and this cycle is generally sufficiently longer than the pedal rotation cycle (see FIG. 8C).

As a result, as shown in FIG. 8 (b), the fluctuation of the observed torque value (τh−τa) which is the value obtained by subtracting the load torque value τa from the manual torque value τh, as shown in FIG. The minimum value m appears in two cycles. When the minimum value m is generated, the human-power torque value τh is zero. Therefore, the minimum value m of the observed torque value matches the value (−τa) obtained by reversing the sign of the load torque value τa.

Then, based on the minimum value m of the observed torque value obtained periodically as shown in FIG. 8B, the load torque value τ shown in FIG.
a and estimate the estimated load torque value τa as the observed torque value.
By adding to (τh−τa), the human-power torque value τh shown in FIG.

In order to estimate the load torque value τa, a method of predicting the load torque until the next minimum value is obtained based on the change of the minimum value of the past observation torque, the minimum value of the current observation torque, By holding the value for a half period of the pedal rotation period, various known methods such as a method of updating the load torque with a delay of a half period of the pedal rotation period can be adopted. As a result, an estimated load torque value approximate to the load torque τa shown in FIG. 8C can be obtained.

Thereafter, the first torque is applied to the manual torque τh.
The same processing as in the embodiment is performed, and from the electric motor (2),
The motor output torque corresponding to the manual torque generated by depressing the pedal is output.

Next, modeling of the bicycle mechanism (1) will be described. As shown in FIG. 7, a torque value (τh + τm−τa) obtained by subtracting the load torque τa from a total value (τh + τm) of the human output torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor; That is, the drive torque value τ of the bicycle mechanism (1) that actually contributes to the running of the bicycle is input to the torque-angular velocity converter (12). Here, the torque-angular velocity converter (12) is represented by the transfer function G (s) of the above equation 1, and the wheel rotational angular velocity ω in actual bicycle running is derived as in the first embodiment. . The derived wheel rotation angular velocity ω is input to the integration calculation unit (13), and is integrated to derive the wheel rotation angle θ.

By modeling the bicycle mechanism (1) as described above, the torque value obtained by subtracting the load torque value τa from the total value of the manual torque value τh and the motor output torque value τm is obtained.
(τh + τm−τa) as an input signal and the wheel rotation angular velocity ω
Can be obtained up to the derivation of the bicycle mechanism transfer function Rn (s). Then, by calculating the inverse transfer function Rn (s) ^-1 from the transfer function Rn (s), the wheel rotational angular velocity ω is used as an input signal, and the input torque value (τh + τm−
The transfer function of the inverse system having τa) as the output signal is obtained.

FIG. 11 shows a control procedure of the power assist controller (8) of the present invention. When the bicycle starts to be driven by human power and motor output, first, in step S10, the motor output torque value τm and the load torque value τa are initialized to 0, and in step S11, the wheel rotation angle θ is obtained from the rotation angle sensor (3). Capture the detection signal.

In step S12, the detected wheel rotation angle θ is input to the differentiator (41) to calculate the wheel rotation angular velocity ω. In step S13, whether the wheel rotation angular velocity ω is positive is determined. Determine whether or not. Step S
If NO is determined in step 13, the process returns to step S10. If YES is determined in the step 13, the process proceeds to a step S14, and the wheel rotation angular velocity ω is calculated by an inverse function calculator.
By inputting to (81), a torque value (τh + τm−τa) is obtained by subtracting the load torque value τa from the total value of the manual torque value τh and the motor output torque value τm. Then, in step S15, the observed torque value (τh-τa) is calculated by inputting the torque value (τh + τm−τa) to the subtractor (43) and subtracting the motor output torque value τm. next,
In step S16, the pedal rotation angle φ is 0 ° or 1
It is determined whether the angle is 80 °, and if YES, the process proceeds to step S17 to estimate the load torque value τa as described above. Then, in step S18, the human-powered torque value τa is derived by adding the estimated load torque value τa to the observed torque value (τh−τa). On the other hand, if NO is determined in the step S16, the process shifts to a step S18, where the current observed torque value (τh−τa)
Is added to the estimated load torque value τa at that time to derive the manual torque value τh. Then, in step S19, an appropriate manual torque value τh ′ for stabilizing the operation of the control circuit is calculated by inputting the manual torque value τh to the stabilization processing circuit (44). Next, in step S20, the human torque value τh ′ is input to the motor torque adjustment circuit (45), thereby generating a motor torque command corresponding to the human torque value τh ′ and supplying it to the electric motor (2). It returns to S11.

Fourth Embodiment In the third embodiment, the load torque is not incorporated in the bicycle mechanism transfer function. On the other hand, in the bicycle with the electric motor of this embodiment shown in FIG. And a load torque component due to air resistance received when riding a bicycle. The overall configuration of the bicycle with an electric motor according to the present embodiment is the same as that of the first embodiment shown in FIG.

FIG. 12 is a block diagram showing a control system of the bicycle with an electric motor according to the present embodiment. First, the power assist controller (80) will be specifically described, and then modeling of the bicycle mechanism (1) will be described.

In FIG. 12, the total value of the human-power torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor, that is, the drive torque value (τ
h + τm) minus the load torque τa ′ (τh
+ Τm−τa ′) is input to the bicycle mechanism (1), and the wheels of the bicycle mechanism (1) are driven. Where the load torque τ
a ′ is the total value (τs + τ) of the load torque component τs due to the inclination of the road surface and the load torque component τd due to the random disturbance noise.
d), which does not include the load torque component τe due to the air resistance received during bicycle running. Then, the rotation angle θ of the wheel is detected by the rotation angle sensor (3), and the detection signal of the wheel rotation angle θ is transmitted to the power assist controller (80).
Is input to

In the power assist controller (80), the wheel rotation angle θ obtained from the rotation angle sensor (3)
Is input to the differential calculator (41), and the wheel rotational angular velocity ω is calculated. The calculated wheel rotational angular velocity ω is input to the inverse function calculator (83). Here, the inverse function calculator (83)
In the model of the bicycle mechanism (1) described later, the input torque value (τh + τm−τa ′) is used as an input signal, and the bicycle mechanism transfer function R up to the derivation of the wheel rotational angular velocity ω is obtained.
It has the inverse function Rn '(s) ^-1 of n' (s). Inverse function R
n ′ (s) ⁻¹ has an input / output relationship opposite to that of the bicycle mechanism transfer function Rn ′ (s), and the wheel rotation angular velocity ω is input to the inverse function Rn ′ (s) ^−1. As a result, the input torque value (τh + τm−τa ′) is derived.

The derived torque value (τh + τm−τa ′) is input to the subtractor (43), and the observed torque value (τh−τa ′) is derived by subtracting the motor output torque value τm. The derived observed torque value (τh−τa ′) is input to a human-powered torque value calculation circuit (84), and a load torque value τa ′ is estimated according to the same principle as that of the third embodiment. The human input torque value τh is derived by adding τa ′ to the observed torque value (τh−τa ′). Here, the load torque value τa ′ is the total value (τs + τd) of the load torque component τs due to the road surface inclination and the load torque component τd due to the disturbance random noise, but the load torque component τs due to the road surface inclination is dominant. Therefore, the fluctuation cycle of the load torque value τa ′ is sufficiently longer than the rotation cycle of the pedal. Therefore, similarly to the third embodiment, the observed torque value
In the variation of (τh−τa ′), 1/100 of the pedal rotation cycle
The minimum value appears in two cycles, and the load torque value τa ′ can be estimated based on the minimum value.

Thereafter, the first torque is applied to the manual torque τh.
The same processing as in the embodiment is performed, and from the electric motor (2),
The motor output torque corresponding to the manual torque generated by depressing the pedal is output.

Next, modeling of the bicycle mechanism (1) will be described. As shown in FIG. 12, the torque value (τh + τm−τa ′) obtained by subtracting the load torque τa ′ (τs + τd) from the total value of the manual torque value τh generated by depressing the pedal and the motor output torque value τm generated by the electric motor. )
Is input to the subtraction unit (71), and the load torque component τe due to the air resistance received during the running of the bicycle is subtracted to calculate the driving torque value τ of the bicycle mechanism (1) that actually contributes to the running of the bicycle. The calculated drive torque value τ is input to the torque-angular velocity conversion unit (12). Here, the torque-angular velocity converter (12) is represented by the transfer function G (s) of the above equation 1, and the wheel rotational angular velocity ω in actual bicycle running is derived as in the first embodiment. . The derived wheel rotation angular velocity ω is input to the integration calculation unit (13), and is integrated to derive the wheel rotation angle θ.
Also, the derived wheel rotational angular velocity ω is a square calculation unit (14)
At the same time, and after squaring the wheel rotation angular velocity ω,
A load torque component τe due to air resistance is derived by multiplying the square value by a coefficient C1 according to the viscosity of air in a wind pressure torque calculation unit (15). The derived load torque component τe is input to the subtraction unit (71).

As described above, the bicycle mechanism (1) separates the load torque component τe due to the air resistance received during running the bicycle from the load torque on the bicycle mechanism (1), and uses the load torque component τe as the bicycle mechanism (1). By modeling, the bicycle mechanism transfer function Rn 'incorporating air resistance
(s) can be obtained. And the transfer function Rn '
By calculating the inverse transfer function Rn ′ (s) ⁻¹ from (s), the wheel rotational angular velocity ω is used as an input signal, and the load torque component τe is calculated from the total value of the manual torque value τh and the motor output torque value τm. As a result, a transfer function of an inverse system is obtained in which a torque value (τh + τm−τa ′) obtained by subtracting a load torque value τa ′ not included is used as an output signal.

According to the bicycles with the electric motors of the first to fourth embodiments, by providing a rotation angle sensor having a simple configuration, a motor output torque can be generated in accordance with human-powered torque. There is no need for a torque detecting mechanism having a simple structure, and thus the bicycle mechanism can be simplified and lightened as compared with the conventional one.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof.
In addition, the configuration of each part of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

For example, in any of the above embodiments, the input signal of the power assist controller is not limited to the detection signal of the wheel rotation angle, and the rotation angular velocity detected by the rotation angular velocity sensor is directly input to the inverse function calculator. It is also possible to use a method. In this case, the differential calculator can be omitted.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an entire configuration of a bicycle with an electric motor according to the present invention.

FIG. 2 is a block diagram illustrating a control system of the bicycle with the electric motor according to the first embodiment.

FIG. 3 is a block diagram illustrating a basic configuration of a model of a bicycle mechanism.

FIG. 4 is a block diagram illustrating a specific configuration of a model of a bicycle mechanism in which loss torque is taken as an element.

FIG. 5 is a flowchart illustrating a control procedure performed by the power assist controller according to the first embodiment.

FIG. 6 is a block diagram illustrating a control system of a bicycle with an electric motor according to a second embodiment.

FIG. 7 is a block diagram illustrating a control system of a bicycle with an electric motor according to a third embodiment.

FIG. 8 is a graph showing fluctuations in an observed torque value, a load torque value, and a human-powered torque value in running a bicycle.

FIG. 9 is a diagram illustrating the relationship between the direction of the pedaling force applied to the pedal and the crank angle.

FIG. 10 is a graph showing a relationship between a manual torque value applied to a bicycle mechanism and a crank angle.

FIG. 11 is a flowchart illustrating a control procedure by the power assist controller according to the third embodiment.

FIG. 12 is a block diagram illustrating a control system of a bicycle with an electric motor according to a fourth embodiment.

FIG. 13 is a diagram illustrating an entire configuration of a conventional bicycle with an electric motor.

FIG. 14 is a block diagram showing a control system of the bicycle with an electric motor.

[Explanation of symbols]

 (1) Bicycle mechanism (2) Electric motor (3) Rotation angle sensor (4) Power assist controller

────────────────────────────────────────────────── (5) References JP-A-5-310175 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62M 23/02 G01L 3/00-3 / 26

Claims (10)

(57) [Claims] 1. A bicycle with an electric motor which assists a driving force by a human power by connecting an electric motor to a bicycle mechanism which can be driven by a human power, wherein the bicycle mechanism has a wheel rotation angle or a rotation angular velocity according to the bicycle mechanism. A sensor for detecting a signal, and a control circuit for controlling the output torque of the electric motor based on the sensor detection signal, wherein the control circuit uses human power and torque given to the bicycle mechanism by the electric motor as input signals, First operation processing means for deriving an input torque value for the bicycle mechanism from the sensor detection signal based on an inverse function of a bicycle mechanism transfer function that outputs a signal corresponding to a wheel rotation angle or a rotation angular velocity as an output signal; Calculating means for subtracting the output torque value of the electric motor from the input torque value for the bicycle mechanism to derive a human-powered torque value , To create a motor torque command corresponding to the derived human power torque value, bicycles electric motor, characterized in that it comprises a motor torque adjusting means for supplying to the electric motor. 2. A bicycle mechanism transfer function, comprising: a subtraction processing unit for subtracting a loss torque value from the input signal; and performing an arithmetic process by a transfer function using the inertial force and the viscous resistance of the bicycle mechanism as parameters. The electric motor-equipped bicycle according to claim 1, further comprising a transfer function unit that derives a rotational angular velocity. 3. A second transfer function unit that derives a loss torque component due to air resistance received during running of the bicycle based on the derived wheel rotational angular velocity is connected to a stage subsequent to the transfer function unit. 3. The bicycle with an electric motor according to claim 2, wherein the torque loss value is input to the subtraction processing unit. 4. An addition processing unit for adding a second loss torque component due to disturbance random noise to a first loss torque component due to the air resistance is interposed between the second transfer function unit and the subtraction processing unit. The bicycle with an electric motor according to claim 3, wherein a result of the addition is input to the subtraction processing unit as the loss torque value. 5. The bicycle with an electric motor according to claim 3, further comprising a noise removing unit that removes a high-frequency component having a frequency higher than the rotation frequency of the pedal, after the first arithmetic processing unit. 6. A third arithmetic processing means having a transfer function for stabilizing the operation of a control circuit is interposed between the second arithmetic processing means and the motor torque adjusting means. A bicycle with an electric motor according to claim 5. 7. A bicycle with an electric motor for assisting a driving force by a human power by connecting an electric motor to a bicycle mechanism which can be driven by a human power, wherein the bicycle mechanism has a wheel rotation angle or a rotation angular velocity according to the bicycle mechanism. A sensor for detecting the signal, and a control circuit for controlling the output torque of the electric motor based on the sensor detection signal. The control circuit calculates a torque value obtained by subtracting the load torque from the driving torque by the human power and the electric motor. As an input signal to the bicycle mechanism,
First arithmetic processing means for deriving an input torque value for the bicycle mechanism from the sensor detection signal based on an inverse function of a bicycle mechanism transfer function that outputs a signal corresponding to a wheel rotation angle or a rotation angular velocity; Second operation processing means for subtracting the output torque value of the electric motor from the input torque value for the bicycle mechanism to derive the observed torque value, and 変 動 the rotation period of the pedal in the variation of the derived observed torque value A third arithmetic processing means for estimating a load torque value for the bicycle mechanism based on the minimum value appearing in the above, and deriving a human torque value given to the bicycle mechanism by adding the load torque value to the observed torque value; Motor torque adjusting means for generating a motor torque command according to the derived manual torque value and supplying the command to the electric motor. Bicycle with an electric motor. 8. The bicycle motor transfer function according to claim 7, wherein the bicycle mechanism transfer function is a transfer function using the inertial force and the viscous resistance of the bicycle mechanism as parameters, and is for deriving a rotational angular velocity from the input signal. bicycle. 9. A bicycle mechanism transfer function for subtracting a load torque component due to air resistance received during cycling from the input signal, and transmitting the subtraction result using the inertia force and viscous resistance of the bicycle mechanism as parameters. A first transfer function unit that derives a rotational angular velocity by performing an arithmetic process using a function, and a second transfer function unit that derives a load torque component due to air resistance received during running of a bicycle based on the derived rotational angular speed. The bicycle with an electric motor according to claim 7, wherein the derived load torque component is input to the subtraction processing unit. 10. A fourth arithmetic processing means having a transfer function for stabilizing the operation of a control circuit is interposed between the third arithmetic processing means and the motor torque adjusting means. A bicycle with an electric motor according to claim 9.