JPH1067378A - Motor controller for motor assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the power assist of a traveling motor even while vehicle speed is zero, and attain desired vehicle speed with the power assist of the traveling motor as a result of the traveling motor being turned off when vehicle speed is above a fixed value. SOLUTION: This motor controller 10 is provided with a driving circuit 16 which supplies the power of a battery 14 to a traveling motor 12, a leg-power sensor 18 which detects leg-power FL with a pedal, a control circuit 22 which controls the driving circuit 16 based on the leg-power FL, a grip force sensor 24 which detect the grip strength FH of a driver, a vehicle sensor 20 which detects vehicle speed (v). The control circuit 22 controls the driving circuit 16 so as to become the vehicle speed (v) corresponding to the grip strength FH when three conditions that the leg-power FL is below a fixed value FLT, the vehicle speed (v) is below a fixed value vT and the grip strength is above a fixed value FHT are satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for an electrically assisted bicycle that can travel while using a traveling motor as an auxiliary.

[0002]

2. Description of the Related Art An electric power assisted bicycle can obtain a large driving force with a small pedaling force by supplementing a constant ratio of power to a pedaling force with a traveling motor. The motor control device incorporated in the electric assist bicycle includes a drive circuit that supplies battery power to the traveling motor, a tread force sensor that detects a tread force on a pedal, a vehicle speed sensor that detects a vehicle speed, and the tread force sensor. And a control circuit for controlling the drive circuit based on the pedaling force detected in step (1) and the vehicle speed detected by the vehicle speed sensor. The control circuit calculates a necessary motor driving force based on the pedaling force and the vehicle speed, and supplies electric power of the battery corresponding to the motor driving force to the traveling motor via the driving circuit.

[0003] Here, time t, the vehicle speed v, the pedal force F _L, the motor drive force F _M, the driving force F (= F _L +
F _M ) and the assist ratio are η (= F _M / F _L ). FIG.
0 and FIG. 11 show the operation of a general motor control device,
FIG. 10 is a graph showing the relationship between time t and driving force F, and FIG.
1 is a graph showing the relationship between the vehicle speed v and the assist ratio η. Hereinafter, description will be made based on these drawings.

[0004] As shown in FIG. 10, pedal force F _L, the time t
Draw a convex curve for. Period T of the pedaling force F _L corresponds to a half rotation of the crank. This is because when the pedal is in the position of top dead center or bottom dead center, because pedal force F _L is approximately zero. Also within one period of the pedal force F _L T, the assist ratio η is always constant. However, if the assist ratio η is always constant, problems such as excessively increasing the vehicle speed and increasing power consumption at high speeds occur. Therefore, as shown in FIG.
It is known that the assist ratio η is gradually reduced when the vehicle speed exceeds a certain vehicle speed v _H (see Japanese Patent Application Laid-Open No. H6-107266).

[0005] By the way, a driver sometimes gets off the electric assist bicycle and walks by pushing the electric assist bicycle by hand while holding the steering wheel (hereinafter, referred to as "hand-operated traveling"). For example, there are cases such as climbing a steep slope or traveling at such a low speed that it is impossible to ride in a well-balanced manner.
Also in this case, there is known a motor control device in which a running motor is used so that the user can easily walk while pushing the electric assist bicycle with a small force (see Japanese Patent Application Laid-Open No. 4-358988). This motor control device is provided with a grip switch that is turned on when the handle is gripped, and drives the traveling motor so as to maintain a constant speed when the following three conditions are satisfied. The conditions are [1] the pedaling force detected by the pedaling force sensor is zero, [2] the vehicle speed detected by the vehicle speed sensor is equal to or higher than a certain value, and [3] the grip switch is turned on.

[0006]

However, such a conventional motor control device has the following problems in manual driving.

(1) Unless the vehicle speed exceeds a certain value, power assist of the traveling motor cannot be obtained. Therefore, the driver has to push the electric assist bicycle to gain momentum until the vehicle speed reaches a constant value. In particular, when traveling uphill, a great deal of labor was required because the electric assist bicycle had to be pushed up against the gravity.

(2) The above three conditions may be satisfied even on a downhill. As a result, the electric assist bicycle becomes faster and may not be easily stopped by the action of gravity.

(3) When the three conditions are met, the traveling motor rotates so as to have a predetermined constant speed.
In some cases, the speed at which the driver walks does not match the speed of the electric assist bicycle. In particular, if the electric assist bicycle is faster than the walking speed of the driver, it is not easy because the driver has to walk in a small run to follow the electric assist bicycle.

[0010]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a motor control device which eliminates such inconveniences and enables appropriate manual driving.

[0011]

SUMMARY OF THE INVENTION The present inventor has found that in manual driving, power assist of the traveling motor can be obtained even when the vehicle speed is zero, and the traveling motor is turned off when the vehicle speed exceeds a certain value. It has been found that the problem of the prior art can be solved if the desired vehicle speed can be obtained by the power assist. The present invention has been made based on this finding.

That is, a motor control device according to the present invention comprises: a drive circuit for supplying battery power to a traveling motor;
A pedaling force sensor that detects a pedaling force on the pedal, a control circuit that controls the drive circuit based on the pedaling force detected by the pedaling force sensor, a gripping force sensor that detects a gripping force of a driver, and a vehicle speed sensor that detects a vehicle speed. Have. In addition to this, the control circuit determines that the pedaling force detected by the pedaling force sensor is equal to or less than a certain value, the vehicle speed detected by the vehicle speed sensor is equal to or less than a certain value, and the gripping force detected by the gripping force sensor is equal to or more than a certain value. And a function of controlling the drive circuit so that the vehicle speed becomes constant.

In the manual driving, the control circuit turns the driving motor through the drive circuit when the three conditions of the pedaling force are equal to or less than a certain value, the vehicle speed is equal to or less than a certain value, and the grip force is equal to or more than a certain value. , Keep the vehicle speed constant.
That is, since the vehicle speed only needs to be equal to or less than the predetermined value, power assist of the traveling motor can be obtained even when the vehicle speed is zero.
Therefore, there is no need to push the electric assist bicycle to increase the momentum until the vehicle speed reaches a constant value, and the labor particularly on the uphill is greatly reduced. Further, when the vehicle speed exceeds a certain value, that is, when the condition is not satisfied, power assist of the traveling motor cannot be obtained, so that the vehicle does not become too fast on a downhill.

The control circuit may control the drive circuit so that the vehicle speed is in accordance with the grip force, instead of controlling the drive circuit so that the vehicle speed is constant. In this case, a desired vehicle speed corresponding to the grip force can be obtained by adjusting the grip force by the driver.

[0015]

FIG. 1 is a functional block diagram showing a basic configuration of an embodiment of a motor control device according to the present invention. Hereinafter, description will be made based on this drawing.

The motor control device 10 includes a traveling motor 12
A driving circuit 16 for supplying electric power of the battery 14 to the
A depression force sensor 18 for detecting the pedal force F _L at 8 (Figure 2),
A control circuit 22 for controlling the driving circuit 16 based on the detected pedal force F _L with depression force sensor 18, the grip sensor 24 that detects a grip force F _H of the driver, a vehicle speed sensor 20 for detecting a vehicle speed v, manually operating And a hand switch 28 for manually operating the gripping force sensor 24. The brake switch 26 and the hand switch 28 are not always necessary. Although not shown, the grip 14 is supplied with power from the battery 14 to the grip force sensor 24, the vehicle speed sensor 20, the pedaling force sensor 18, the control circuit 22, and the like.

In addition, the control circuit 22 has the following functions during manual driving. (B) depressing force F _L is less than a predetermined value F _LT, vehicle speed v is below a predetermined value v _T, grip strength F _H is a constant value F _HT above, three conditions that are met, according to certain vehicle speed v or grip strength F _H The driving circuit 16 is controlled so that the vehicle speed becomes v. (B) When the brake switch 26 is turned on, the drive circuit 16 is controlled so that the traveling motor 12 always stops.

Next, specific examples of the above components will be listed. The running motor 12 is a DC brushless motor, the battery 1
4 is a lead oxide battery. The drive circuit 16 includes a switching transistor circuit that energizes the traveling motor 12, a PWM circuit that controls the amount of energization by a pulse width, and an electromagnetic switch that is connected to the battery 14. Pedal force sensor 18
Is a load cell or a piezo element. Vehicle speed sensor 2
0 is a tacho generator or a rotary encoder. The control circuit 22 includes a CPU, a ROM, a RAM, an input / output interface circuit, and the like, and various functions are realized by a computer program. The grip force sensor 24 includes an elastic member and a potentiometer. The brake switch 26 and the hand switch 28 are general mechanical switches.

FIG. 2 is an external view of an electric assist bicycle in which the motor control device 10 is incorporated. Hereinafter, description will be given based on FIG. 1 and FIG.

The electrically assisted bicycle 30 incorporates a motor control device 10, a running motor 12, a battery 14, a power unit 32, an auxiliary device 33, and the like, in addition to the configuration of a normal bicycle. Also, as in a normal bicycle, the crankshaft 34 has two ends perpendicular to the crankshaft 34 at both ends.
A pedal 38 is rotatably attached to the tip of the crank 36.

The pedaling force sensor 18 is attached to the pedal 38 or the crankshaft 34 or the like. The vehicle speed sensor 20 is attached to the crankshaft 34, the rear wheel shaft 80, or the like. The grip force sensor 24 or the hand switch 28 is located at a position a1 below the saddle 82 and a position a2 below the handle 84, such as a position a1 under the saddle 82, which is hard to touch during the treading force traveling and a touch during the manual pushing traveling.
Alternatively, the saddle shaft 86 is attached to a position a3 on the rear wheel 52 side. The brake switch 26 is in the position a2, the position a1.
Or, it is attached to the position a3 or the like.

FIG. 3 is a functional block diagram of the electric assist bicycle 30. Hereinafter, description will be made with reference to FIGS. However, in FIG. 3, the same parts as those in FIG. 1 or FIG.

The power generated by the traction motor 12 via the one-way clutch 40 and speed reducer 42, is transmitted to the resultant force device 44 as a motor driving force F _M. Pedal 38
Pedal force F _L applied to is transmitted to the resultant force device 44 via the crank shaft 34 and the one-way clutch 46. In the resultant force device 44, and a motor drive force F _M and pedal force F _L combined and output as a driving force _{F (= F L + F M} ). The driving force F rotates the rear wheel 52 via the power transmission means 48 and the one-way clutch 50. Thereby, the electric assist bicycle 30 runs. The one-way clutches 40, 46, 50 are clutches that transmit power only in the direction in which the electric assist bicycle 30 moves forward. The speed reducer 42 reduces the rotation speed according to the gear ratio.
The power transmission means 48 is a chain, a drive shaft, a belt, or the like.

FIGS. 4 and 5 are schematic views showing the structure of the resultant device 44. FIG. Hereinafter, description will be made with reference to FIGS.

The resultant device 44 is somewhat similar in structure to the Oldham shaft coupling. That is, the resultant force device 44 includes a rotating plate 62 _L fixed to the pedal-side shaft 60 _L for transmitting the pedaling force F _L, the motor-side shaft 60 for transmitting a motor drive force F _M
The rotating plate 62M fixed to _M and the rotating plates _60L , _60M
Plate 64 sandwiched between the rotating plate 6 and the rotating plate 6
0 _L , 60 _M sloped cams 66 _L , 66 _M formed
And _M, and the slope 68 _L, 68 _M, which is formed in the intermediate plate 64 with meshes with slanted cam 66 _L, 66 _M, an intermediate plate 6
A sliding recess 70 for slidably inserted through the rolling elements (not shown) in the circumferential edge 64a of 4, a compression spring 72 _L, 72 _M for urging the sliding recess 70 in opposite directions, the compression spring 72
_L, and has a 72 and a fixing portion 74 _L, 74 _M to secure the _M structure. Therefore, the slope cam 66 _L is
Intermediate plate 64 a force P and the intermediate plate 64 to rotate by the component force of the pedal force F _L to the force moving axially p to be transmitted to the inclined surface 68 _L. Likewise, slanted cam 66 _M is a force M and the intermediate plate 64 to rotate the intermediate plate 64 and the component force of the motor driving force F _M to the force moving in the axial direction m, and transmits to the slopes 68 _M.

The linear potentiometer 76 comprises a resistor 761 to which a constant DC voltage Vcc is applied and a movable contact 762 fixed to the sliding recess 70. From the linear potentiometer 76, a voltage _VL determined by the position of the movable contact 762 on the resistor 761 is output.

The compression springs 72 _L and 72 _M have the same material and structure. Therefore, if F _M = F _L , m
= P, the intermediate plate 64 is located exactly at the center of the rotary plates 60 _L and 60 _M (FIG. 4). If F _M <F _L , then m <p, so that the intermediate plate 64 is
To a position balanced with the biasing force of 2 _M, moves the rotating plate 60 _M side (Fig. 5). Conversely, if F _M > F _L , then m
> Since the p, intermediate plate 64, to a position commensurate with the urging force of the compression spring 72 _L, moves to the rotary plate 60 _L side (not shown).

At this time, the movable contact 7 together with the intermediate plate 64
By 62 moves, the motor driving force F _M and force F
_The voltage _VL is output from the linear potentiometer 76 to the control circuit 22 (FIG. 3) in accordance with the magnitude relationship with _L.
The control circuit 22, for example, as the assist ratio η is always 1 or less, i.e. to always be F _M ≦ F _L, and controls the driving circuit 16 (FIG. 3). In other words, the linear potentiometer 76 detects the ratio between the motor drive force F _M and pedal force F _L, operates as a kind depression force sensor. Therefore, the control circuit 22 controls the linear potentiometer 76
The drive circuit 16 can be controlled using only
The drive circuit 16 can be controlled using only the treading force sensor 18 (FIG. 3).

FIG. 6 is a flowchart showing an example of the operation of the motor control device 10. Hereinafter, the operation of the control circuit 22 will be mainly described with reference to FIGS.

When the driver turns on a main switch (not shown), the operation shown in FIG. 6 starts (step 10).
1). First, the A = 0 (step 102), enter the depression force F _L, the vehicle speed v and grip strength F _H, the following pedal force F _L is a constant value F _LT, vehicle speed v is below a predetermined value v _T, grip strength F _H is a constant value F _HT above, that when aligned for all three conditions (steps 103 to 105), executes the hand driving control for controlling the driving circuit 16 so that the vehicle speed v in accordance with the grip strength F _H (step 106). Subsequently, A = 1 is set (step 107), and the process returns to step 103.

On the other hand, if the condition is not satisfied in one of the ~, pedal force F _L is a constant value F ₁ or more and grip strength F _H determines whether or not a predetermined value F ₂ or more (step 108).
If F _L> F ₁ and F _H> F _2, since pedaling force F _L and grip strength F _H is applied simultaneously for some reason, it performs the duplication process (step 109), returns to step 103. The duplication processing method in step 109 includes the following. 1) the travel motor 12 is turned off, pedal force F _L
Alternatively, the state is maintained until either the grip force F _H is reached. 2) Execute a fail process such as not restarting unless the main switch is turned off. 3) Exclusive control such as driving the traveling motor 12 at an ultra-low level output is executed.

In step 108, if F _L > F ₁ and F _H > F _{2 are} not satisfied, it is determined whether or not A = 1 (step 110). If A = 1, A =
If it is 1, the hand-held traveling control is stopped (step 11).
1) The normal pedaling travel control is executed (step 11).
2) Return to step 102. The above operation is continued until the main switch is turned off.

In step 106, when the three conditions (1) to (4) are continuously satisfied for a certain period of time, the manual driving control may be executed. in this case,~
Even if these three conditions are instantaneously satisfied, the hand-held traveling control is not executed instantaneously, so that the operation can be stabilized. Whether or not the certain time has continued is determined by a timer built in the control circuit 22.

FIGS. 7 and 8 are graphs showing the relationship between the grip force F _H and the vehicle speed v in the manual driving control of the motor control device 10. Hereinafter, description will be made based on these drawings.

The relationship b1 is, grip strength F _H from F _HT to F _HH is, the vehicle speed v is increased in proportion to the grip F _H, grip strength F _H is F
Above the _HH, the vehicle speed v becomes constant regardless of the grip F _H. The relation b2 is that when the grip force F _H exceeds F _HT , the grip force F _H
, A constant vehicle speed v can be obtained. Relationship b3, corresponding to the increase in grip strength F _H, the vehicle speed v is increased slightly → explosion → slight increase → the curve changes. Relationship b4 the vehicle speed v increases in proportion to the grip F _H. Relationship b5, corresponding to the increase in grip strength F _H, the vehicle speed v is increased stepwise.

[0036] Figure 9 is a time chart showing the hand driving control of the motor control device 10, FIG. 9 [i] is pedal force F _L, 9 [ii] is the vehicle speed v, 9 [iii] the grip F _H , FIG. 9
[iv] is the motor current i, and FIG. 9 [v] is the brake switch 2
6 (see FIG. 1 or FIG. 3). Hereinafter, description will be made based on this drawing.

(A) shows that in the region of F _H > F _HT ,
Pedal force F _L is less than a predetermined value F _LT, vehicle speed v is below a predetermined value v _T, grip strength F _H is a constant value F _HT above, since the three conditions that are met all is when the motor current i flows.
(B) is a case where the condition of v> v _T is not satisfied, that is, the motor current i is cut off. (C)
Since longer meets the F _L> F _LT viz condition is when the motor current i is cut off. (D)
This is a case where the motor current i is cut off when the brake switch 26 is turned on.

It is needless to say that the present invention is not limited to the above embodiment. For example, the motor control device according to the present invention can be applied not only to an electric assist bicycle but also to an electric assist wheelchair, an electric assist cargo, and the like.

[0039]

According to the motor control device according to the present invention as set forth in claims 1, 2, 3 and 4,
When the three conditions, that is, the pedaling force is equal to or less than a certain value, the vehicle speed is equal to or less than a certain value, and the grip force is equal to or more than a certain value, the driving motor is driven.If the vehicle speed is equal to or less than a certain value, the vehicle speed is zero. However, power assist of the traveling motor can be obtained. Therefore, it is possible to save the trouble of pushing the electric assist bicycle until the vehicle speed reaches a constant value to increase the momentum, and it is possible to greatly reduce the labor particularly on the uphill. Also,
If the vehicle speed exceeds a certain value, that is, if the conditions are not satisfied, power assist of the traveling motor cannot be obtained, so that it is possible to prevent the vehicle speed from becoming too fast on a downhill.

According to the motor control device according to the second, third or fourth aspect of the present invention, the driving motor is driven so as to have a vehicle speed corresponding to the grip force. A desired vehicle speed according to the grip force can be obtained.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a basic configuration in an embodiment of a motor control device according to the present invention.

FIG. 2 is an external view of an electric assist bicycle incorporating the motor control device of FIG. 1;

FIG. 3 is a functional block diagram of the electric assist bicycle of FIG. 2;

FIG. 4 is a schematic diagram showing a configuration of a resultant device in the electrically assisted bicycle of FIG. 2;

FIG. 5 is a schematic diagram showing a configuration of a resultant device in the electric assist bicycle of FIG. 2;

FIG. 6 is a flowchart illustrating an example of an operation of the motor control device of FIG. 3;

FIG. 7 is a graph showing a relationship between a grip force and a vehicle speed in the manual driving control of the motor control device of FIG. 3;

FIG. 8 is a graph showing a relationship between a grip force and a vehicle speed in the manual driving control of the motor control device of FIG. 3;

FIG. 9 is a time chart showing manual driving control of the motor control device in FIG. 3, in which FIG. 9 [i] is the pedaling force, FIG. 9 [ii] is the vehicle speed, FIG. 9 [iii] is the gripping force, and FIG. 9 [iv] Is the motor current, FIG.
[v] indicates each brake switch.

FIG. 10 is a graph showing a relationship between time and driving force in the operation of the conventional motor control device.

FIG. 11 is a graph showing a relationship between a vehicle speed and an assist ratio in the operation of the conventional motor control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Motor control device 12 Running motor 14 Battery 16 Drive circuit 18 Treading force sensor 20 Vehicle speed sensor 22 Control circuit 24 Grip force sensor 26 Brake switch 28 Hand switch 30 Electric assist bicycle F _L Treading force F _H Gripping force v Vehicle speed

Claims (4)

[Claims] 1. A driving circuit for supplying electric power of a battery to a traveling motor, a pedaling force sensor for detecting a pedaling force on a pedal, and a control circuit for controlling the driving circuit based on the pedaling force detected by the pedaling force sensor. A motor control device for an electrically assisted bicycle, comprising: a grip force sensor for detecting a grip force of a driver; and a vehicle speed sensor for detecting a vehicle speed, wherein the control circuit determines that the pedaling force detected by the pedaling force sensor is a constant value. Below, and has a function of controlling the drive circuit so that the vehicle speed is constant when the vehicle speed detected by the vehicle speed sensor is equal to or less than a certain value and the grip force detected by the grip force sensor is equal to or more than a certain value. A motor control device for an electrically assisted bicycle. 2. A drive circuit for supplying electric power of a battery to a traveling motor, a tread force sensor for detecting a tread force on a pedal, and a control circuit controlling the drive circuit based on the tread force detected by the tread force sensor. A motor control device for an electrically assisted bicycle, comprising: a grip force sensor for detecting a grip force of a driver; and a vehicle speed sensor for detecting a vehicle speed, wherein the control circuit determines that the pedaling force detected by the pedaling force sensor is a constant value. Below, and when the vehicle speed detected by the vehicle speed sensor is equal to or less than a certain value, and when the grip force detected by the grip force sensor is equal to or more than a certain value, the driving circuit is controlled so that the vehicle speed is in accordance with the grip force. A motor control device for an electrically assisted bicycle having a function. 3. A manually operated brake switch is provided, and said control circuit has a function of controlling said drive circuit so that said running motor always stops when said brake switch is turned on. 3. The motor control device for an electrically assisted bicycle according to claim 1. 4. The control circuit according to claim 1, wherein the pedaling force detected by the pedaling force sensor is equal to or less than a constant value, the vehicle speed detected by the vehicle speed sensor is equal to or less than a constant value, and the gripping force detected by the gripping force sensor is equal to or greater than a constant value. 3. The motor control device for an electrically assisted bicycle according to claim 1, wherein in the case of (1), the driving circuit is controlled after the state continues for a predetermined time. 4.