JP2002255082A - Control device for power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate periodic variation of a pedaling force and generate proper auxiliary power in accordance with a road surface. SOLUTION: A traveling resistance calculating part 62 calculates actual traveling resistance based on a total driving force wherein human power based on the pedaling force and electric auxiliary power by a motor 14 are added and the variation of a vehicle speed. A standard resistance calculating part 60 retrieves a map based on the vehicle speed and calculates standard traveling resistance at a flat place. An auxiliary power calculating part 63 calculates: auxiliary power Pm capable of compensating a difference between the actual traveling resistance Ra and the standard traveling resistance Rr. A motor torque calculating part 64 calculates motor torque T based on the auxiliary power Pm and instructs the motor 14. By supplying the auxiliary power, a rider on a power-assisted bicycle can drive on an inclined road surface with the same traveling feeling as on a flat place.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric assist bicycle, and more particularly, to a driving device having the same driving feeling as a bicycle having no electric assist device (hereinafter referred to as "normal bicycle"). The present invention relates to a control device for an electric assisted bicycle suitable for:

[0002]

2. Description of the Related Art A manual drive system for transmitting a force applied to a pedal by human power, that is, a treading force to a rear wheel, and a motor drive system capable of adding auxiliary power to the human drive system in accordance with the treading force are provided. Electric assisted bicycles are known. This electrically assisted bicycle is configured to assist human power with a motor output according to the pedaling force and the pedal rotation speed. As the pedaling force increases, the motor output increases and the human power is reduced. That is, the motor output is a pedal force proportional output.

It is also conceivable to generate a motor output so as to assist the weight difference between an electric assist bicycle and a normal bicycle. For example, Japanese Patent Application Laid-Open No. 8-127386 proposes a motor-assisted bicycle in which the difference in weight from a normal bicycle is assisted by a motor so as to reduce the burden on a person during manual driving.

[0004]

As described above, in the conventional electric assist bicycle, the motor output is proportional to the pedaling force, so that the pedaling force changes periodically according to the pedal rotation. Auxiliary power is applied in the direction to amplify the dynamic change. Therefore, the load on the person can be reduced by the auxiliary power, but the vehicle speed tends to fluctuate periodically.

On the other hand, if the difference in weight of the bicycle is covered by the auxiliary power without considering the treading force as described in the above-mentioned publication, the vehicle speed does not fluctuate periodically. But,
Conventionally, it has not been considered to provide the auxiliary power without taking the pedaling force into consideration even when riding in a vehicle, and it has been limited to only partial use during manual driving. Therefore, when the driving on an inclined road surface is taken into consideration, other auxiliary control means such as an inclination sensor are required.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an electric assisted bicycle that can be driven with the same running feeling as a normal bicycle on both a sloped surface and a flat road, without amplifying the periodic fluctuation of the pedaling force. It is to provide a control device.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a human-powered drive system for transmitting human-powered driving force to rear wheels, and a motor-driven system for transmitting motor-driven power to rear wheels. A first feature of the control device for an electrically assisted bicycle including a control system is that control means for generating a driving force corresponding to the actual running resistance in the motor drive system is provided.

According to the first feature, the driving force of the motor is generated so as to reduce the resistance (actual running resistance) actually received by the electric bicycle during running. Therefore, the fluctuation of the vehicle speed can be made smaller than that which generates the auxiliary power by following the pedaling force that periodically changes in magnitude,
The driving force can be generated appropriately in response to the change in running resistance caused by the inclination of the road surface.

Further, the present invention is characterized in that the actual running resistance is calculated as a function of the vehicle speed change amount with respect to the total driving force of the driving force by the human power and the driving force by the motor given during the scheduled period. There are features. According to the second feature,
Auxiliary power can be accurately provided according to the driving state of the vehicle.

A third feature of the present invention is that the driving force generated by the motor drive system is controlled such that the actual running resistance of the vehicle substantially coincides with the resistance of the vehicle when traveling on level ground. Since the auxiliary power is applied so that the actual running resistance becomes the same as when traveling on level ground, the vehicle can be driven with the same feeling as traveling on flat ground regardless of the inclination of the road surface.

Further, according to the present invention, the resistance when traveling on level ground is as follows:
The fourth feature lies in that the resistance is set to the resistance during normal running on a flat bicycle. According to the fourth feature, the electric assisted bicycle is
It can be driven lightly with the same feeling as a bicycle without an electric assist device (normal bicycle).

Further, the present invention includes a road surface inclination determining means for determining that a change has occurred in the inclination of the traveling road surface, and the motor drive system generates the signal when it is determined that the traveling road surface has changed to the upward inclination. The fifth feature is that the driving force to be generated is reduced for a predetermined period, and when it is determined that the traveling road surface has changed to a downward slope, the driving force generated by the motor drive system is controlled to be increased for a predetermined period. .

According to the fifth feature, the running resistance increases or decreases for a predetermined period when the road surface goes uphill or downhill. Thus, the driver can drive while feeling the change in the inclination of the road surface.

Further, according to the present invention, the road surface inclination judging means may be configured to perform an uphill run when the value of the ratio is larger than a predetermined value, based on the value of the ratio between the actual running resistance and the predetermined leveling resistance. A sixth feature is that a means for judging a downhill when the value of the ratio is smaller than the expected value is provided.
According to the sixth aspect, the inclination of the road surface can be determined by the actual running resistance detecting means without providing the inclination sensor.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a side view of the electric assist bicycle including the control device according to the embodiment of the present invention. A body frame 1 of the electric assist bicycle includes a head pipe 2 located in front of the vehicle body, a down pipe 3 extending rearward and downward from the head pipe 2, a rear fork 4 connected to the down pipe 3 and extending rearward, and a down pipe 3 And a seat post 5 that rises upward from the lowermost end of the seat post.

A front fork 6 is rotatably supported on the head pipe 2. A front wheel 7 is pivotally supported at a lower end of the front fork 6, and a steering handle 8 is attached to an upper end of the front fork 6. The steering handle 8 is provided with a brake lever 9, and a cable 10 drawn from the brake lever 9 is connected to a front wheel brake 11 fixed to the front fork 6. Similarly, a brake lever for a rear wheel brake is also provided on the steering handle 8, but is not shown. The brake lever 9 is provided with a brake sensor (not shown) for detecting that the brake lever 9 has been operated.

A pair of left and right stays 12 connected to the upper end of the seat post 5 extend rearward and downward, and are connected to the rear fork 4 near the lower end. A rear wheel 13 is supported by a member formed by connecting the rear fork 4 and the stay 12, and a motor 14 is supported by the member and coaxial with a hub of the rear wheel 13 as an auxiliary power source. As the motor 14, a three-phase brushless motor having high torque and low friction is preferable. The specific structure and control of the motor 14 will be described later.

A support shaft 16 having a seat 15 at its upper end is mounted on the seat post 5 so that the height of the seat 15 can be adjusted. A battery 17 for supplying electric power to the motor 14 is provided below the seat 15 and between the seat post 5 and the rear wheel 13. Battery 17 is seat post 5
Is held by a bracket 18 fixed to the bracket. A power supply 19 is provided on the bracket 18. The power supply 19 is connected to the motor 14 by an electric wire (not shown) and connected to an electrode of the battery 17. The upper part of the battery 17
It is supported by the seat post 5 with a fastener consisting of a band 20 and a buckle fitting 21.

At the intersection of the down pipe 3 and the seat post 5, a crankshaft 22 extending to the left and right of the vehicle body is supported, and a pedal 24 is connected to the crankshaft 22 via a crank 23. A drive sprocket 25 is connected to the crankshaft 22 via a pedal force sensor (not shown), and the pedal force applied to the pedal 24 is transmitted to the drive sprocket 25 via the pedal force sensor. Drive sprocket 25
A chain 27 is stretched between the driven sprocket 26 and the driven sprocket 26 provided on the hub of the rear wheel 13. A chain cover 28 is provided on the tension side of the chain 27 and the drive sprocket 25.
Is covered. The crankshaft 22 is provided with a rotation sensor for the crankshaft 22 (not shown). As the rotation sensor, a known sensor such as a sensor used for detecting crankshaft rotation of an automobile engine can be used.

Next, the pedaling force detecting device mounted on the crankshaft 22 will be described. FIG. 17 is a cross-sectional view of the vicinity of the crankshaft 22, and FIG. 18 is a view taken along the line AA of FIG. Caps 101L and 101R screwed into both ends of a support pipe 100 fixed to the down pipe 3 and a crankshaft 22
Between the ball bearing 102 and the step formed
L and 102R are respectively inserted and rotatably support the crankshaft 22.

At the left and right ends of the crankshaft 22, bolts 10
The cranks 23 are respectively fixed by nuts 103C conforming to 3B (only the right side is shown). The inner ring 105 of the one-way clutch 104 is fixed between the crank 23 and the support pipe 100. A drive sprocket 25 is rotatably supported on the outer periphery of the inner ring 105 via a bush 105A. The position of the drive sprocket 25 in the thrust direction is regulated by the nut 106A and the plate 106B.

The drive sprocket 25 is provided with a cover 107 integrally therewith. A transmission plate 108 is provided in a space surrounded by the drive sprocket 25 and the cover 107.
Are arranged. The transmission plate 108 is coaxial with the drive sprocket 25 and is supported so that a predetermined amount of displacement is allowed in the rotation direction about the crankshaft 22.

Drive sprocket 25 and transmission play 1
A plurality of (here, six) windows 109 are formed so as to straddle 08, and compression coil springs 110 are housed inside the windows 109, respectively. Compression coil spring 1
10 is a drive sprocket 25 and a transmission plate 108
In the case where there is a shift in the rotational direction between them, they act to generate a drag against the shift.

On the inner periphery of the hub of the transmission plate 108, ratchet teeth 11 as an outer ring of the one-way clutch 104 are provided.
The ratchet teeth 111 are engaged with a ratchet pawl 113 supported by the inner ring 105 and radially urged by a spring 112. The one-way clutch 104 is provided with a cover 114 for dust prevention.

The transmission plate 108 is provided with a locking hole 116 with which a projection 115 for transmitting the treading force fixed to the treading force transmission ring 124 is engaged. Drive sprocket 25
Is provided with a window 117 through which the projection 115 can be engaged with the locking hole 116, and the projection 115 penetrates the window 117 and is fitted into the locking hole 116.

A plurality of small windows (three in this case) other than the window 109 are formed over the drive sprocket 25 and the transmission plate 108, and a compression coil spring 118 is provided inside the small window. Will be accommodated. The compression coil spring 118 moves the transmission plate 108 in its rotation direction 11.
It is arranged so as to urge to the 9 side. That is, the transmission plate 108 acts in a direction to absorb backlash at the connection portion between the drive sprocket 25 and the transmission plate 108.
Functions to be transmitted to the drive sprocket 25 with good responsiveness.

A sensor portion (pedal force sensor) 47 of a pedal force detecting device is mounted on the drive sprocket 25 near the vehicle body, that is, on the down pipe 3 side. The pedal force sensor 47 includes an outer ring 120 fixed to the drive sprocket 25,
A sensor main body 121 is provided rotatably with respect to the outer ring 120 and forms a magnetic circuit.

The outer ring 120 is made of a material having electrical insulation, and is fixed to the drive sprocket 25 with bolts (not shown). A cover 122 is provided on the outer ring 120 on the drive sprocket 25 side, and is fixed to the outer ring 120 with a set screw 123.

FIG. 19 is an enlarged sectional view of the sensor main body 121. A coil 125 is provided concentrically with the crankshaft 22, and is disposed on both axial sides of the coil 125.
A pair of cores 126 projecting in the outer circumferential direction of the coil 125
A, 126B are provided. In addition, the cores 126A,
A first derivative 127 and a second derivative 128 having a ring shape are provided between 126B. First derivative 127 and second derivative 1
28 is configured to be displaceable in the circumferential direction with respect to each other in accordance with the treading force transmitted from the treading force transmission ring 124, and this displacement is configured to change the amount of overlap between the cores 126 </ b> A and 126 </ b> B. You. As a result, when the coil 125 is energized, the magnetic flux of the magnetic circuit including the cores 126A and 126B and the core collar 129, and the first and second inductors 127 and 128 changes according to the pedaling force. Thus, the coil 12 which is a function of this magnetic flux
5, the pedaling force can be detected. 19, reference numerals 130 and 131 denote support members for the sensor main body 121, reference numeral 132 denotes a bearing, and reference numeral 133 denotes a lead wire drawn out of the coil 125.

The above-described pedal force sensor is disclosed in Japanese Patent Application No. Hei 11-251870 (reference number A99-10).
26)) is described in more detail. The treading force sensor is not limited to the one having the above-mentioned structure, and a known sensor may be used.

FIG. 3 is a sectional view of the motor 14. A cylinder 30 incorporating a transmission is supported by a shaft 31 on a plate 29 projecting rearward from a joint between the rear end of the rear fork 4 and the lower end of the stay 12. A wheel hub 32 is fitted on the outer periphery of the cylinder 30. The wheel hub 32 is an annular body having an inner cylinder and an outer cylinder, and the inner peripheral surface of the inner cylinder abuts the outer periphery of the cylinder 30. Wheel hub 3
2 has a connecting plate 33 projecting from the cylinder 30.
Are fixed by bolts 34. Neodymium magnets 35 constituting the rotor-side magnetic poles of the motor 14 are arranged at predetermined intervals on the inner periphery of the outer cylinder of the wheel hub 32. That is, the outer cylinder forms a rotor core holding the magnet 35.

A bearing 3 is provided on the outer periphery of the inner cylinder of the wheel hub 32.
6 are fitted, and the stator support plate 3
7 are fitted. A stator 38 is arranged on the outer periphery of the stator support plate 37 and is attached by bolts 40.
The stator 38 is arranged so as to have a predetermined gap with the rotor core, that is, the outer cylinder of the wheel hub 32, and a three-phase coil 39 is wound around the stator 38.

On the side surface of the stator support plate 37, a magnetic pole sensor 41 composed of a Hall element is provided. The magnetic pole sensor 41 detects a change in magnetic flux when a magnet 42 protruding from the wheel hub 32 passes, and outputs a position signal of the wheel hub 32 as a rotor. The magnetic pole sensors 41 are provided at three locations corresponding to each phase of the motor 14.

On the side surface of the stator support plate 37, the position signal from the magnetic pole sensor 41 is used.
9 is provided with a control board 43 for controlling the energization of
On the control board 43, control elements such as a CPU and an FET are mounted. The control board 43 is provided with the magnetic pole sensor 41.
Can be integrated with the mounting board for

A spoke 44 connected to a rim of a rear wheel (not shown) is fixed to the outer periphery of the wheel hub 32. Further, a bracket 46 is fixed to the stator support plate 37 on a side opposite to the side on which the control board 43 and the like are mounted by bolts 45, and the bracket 46 is connected to the plate 29 of the vehicle body frame by bolts (not shown). You.

As described above, the three-phase brushless motor 14 including the stator and the rotor arranged coaxially with the shaft 31 of the rear wheel 13 is provided, and adds to the human power transmitted by the chain 17 and the driven sprocket 26. Generates auxiliary power.

Next, the energization control, that is, the output control, for the motor 14 will be described. FIG. 4 is a diagram illustrating a generation mode of the auxiliary power on the assumed traveling path, and the horizontal axis is a time axis. Here, it is assumed that the road surface starts on a flat road, travels up an uphill and downhill, and travels on a flat road again. On this assumed traveling road, a traveling pattern is set in which the speed is gradually increased from a flat road, the vehicle is approaching an uphill, and then traveling at a constant speed. In the drawing, the driving force indicated by the curve is related to the conventional control in which the auxiliary power is generated in proportion to the pedaling force, and the small curve represents the driving force (human power) Ph due to the pedaling force Ta, and has the same phase as this curve. The large curve shows the auxiliary power Pm by the motor. As can be understood from this figure, the human power Ph
And the auxiliary power Pm are controlled so as to have a one-to-one ratio, although the auxiliary power Pm increases on an uphill, but the human power Ph is also at a high level.

On the other hand, in the present embodiment, a flat road,
Control is performed so that a person can share a predetermined driving force, that is, a driving force corresponding to the flat-land running resistance of the light vehicle, on both the uphill and downhill road surfaces. Specifically, of the running resistance Ra generated by running, only the resistance when driving a relatively light-weight vehicle, which is generally called a light-duty vehicle, on a flat road among ordinary bicycles is borne by human power, and Is assisted by the output of the motor 14. As a result, the driver can drive on any flat road surface as if driving with a light vehicle. In FIG. 4, a motor torque is generated so as to give the auxiliary power Pm to the resistance Ra actually generated during running. At this time, (R
The motor torque is determined so that a-Pm) becomes a predetermined value. That is, the driver can run the bicycle with the predetermined pedaling force Ta corresponding to the resistance of the light vehicle to running on flat ground.

Hereinafter, the output control will be described in more detail. However, the above description is a basic concept of the output control in the present embodiment, and the specific control described below includes various modifications.

FIG. 1 is a functional block diagram of a main part of a control device for controlling the output of the motor 14 according to the actual running resistance.
The calculation unit and the storage unit in this function can be realized by a microcomputer. In the figure, a treading force detecting section 51 detects a treading force Ta based on a detection signal of a treading force sensor 47. The crank rotation speed detecting section 52 detects the crank rotation speed NCR based on the detection signal of the crank rotation sensor 48. The human power calculator 53 calculates a driving force Ph proportional to the pedaling force input from the pedal 24 using the following equation (Equation 1). Ph = Ta × NCR × k1 (Equation 1). Here, k1 is a coefficient.

The total driving force calculating section 54 calculates the total driving force Pw by adding the driving force Ph obtained by human power, the motor torque T and the motor output based on the motor speed Nm. The motor torque T used here is the previous value, that is, the value T-1 stored in the previous value memory 61.

The motor speed detector 56 detects the motor speed Nm based on the detection signal of the motor speed sensor 49.
The vehicle speed detector 57 detects the vehicle speed V based on the detection signal of the vehicle speed sensor 50. The magnetic pole sensor 41 can be used as the motor rotation sensor 49 and the vehicle speed sensor 50.

The vehicle speed memory 58 stores a previously detected value V of the vehicle speed V.
-1 is stored. The vehicle speed change amount calculation unit 59 calculates a difference ΔV between the previous value V-1 of the vehicle speed V and the current value V. The standard running resistance calculation unit 60 searches a map of the normal running resistance Rr of a normal bicycle on the basis of the vehicle speed V.

The running resistance calculation unit 62 searches the map for each vehicle speed V based on the total driving force Pw and the vehicle speed change amount ΔV to calculate the actual running resistance Ra. A map for obtaining the actual running resistance Ra will be described later. Note that the running resistance calculation unit 62 may use an integrated value of the total driving force Pw instead of the total driving force Pw. That is, the output of the total driving force integrating unit 55 can be used. The total driving force integration unit 55 calculates the integrated value Ph by integrating the total driving force Pw for each scheduled time or each scheduled period. For example, the total driving force Pw during one rotation of the crankshaft 22
Is obtained.

The auxiliary power calculator 63 subtracts the normal running resistance Rr of the bicycle from the actual running resistance Ra to obtain the motor 14
The auxiliary power Pm is calculated. Motor torque calculator 6
In step 4, a motor torque T for instructing the motor 14 is calculated based on the motor speed Nm and the auxiliary power Pm. The motor torque T is obtained by searching a map previously set as a function of the motor speed Nm and the auxiliary power Pm. The calculated motor torque T is output to the control unit of the motor 14 and stored in the previous value memory 61.

As described above, according to the above-described control device, the actual running resistance Ra is obtained from the change in the vehicle speed corresponding to the input energy during one row of the pedal 24. Of the actual running resistance Ra, the actual running resistance Ra is determined. Running resistance Rr when traveling on level ground
Is removed from the output of the motor 14 and added to human power.

FIG. 5 is a block diagram showing main functions (No. 2) of the control device. This control device includes a road surface inclination determining means, and can increase or decrease the auxiliary power Pm according to the road surface inclination. In FIG. 5, an assist vehicle flat-land running resistance calculation unit 65 is provided, and a predetermined map is searched based on the vehicle speed V to calculate the assist vehicle flat-land running resistance R1. Based on the actual running resistance Ra calculated by the running resistance calculating section 62 and the assisted vehicle flat-land running resistance R1, the road-surface inclination determining section 66 determines that the actual running resistance Ra is larger than the flat-land running resistance R1 by more than planned. If it is determined that the vehicle is traveling, and if the actual traveling resistance Ra is smaller than the predetermined value, then it is determined that the vehicle is traveling downhill. When starting uphill, timer 6
7 and activates the auxiliary force increasing unit 68 until the measurement by the timer 67 is completed. On the other hand, when starting a downhill,
The timer 69 is started, and the auxiliary power reduction unit 70 is energized until the measurement by the timer 69 ends.

The auxiliary power increasing section 68 corrects the coefficient used for calculating the auxiliary power so that the auxiliary power Pm increases, and the auxiliary power reducing section 70 converts the coefficient used for calculating the auxiliary power into the auxiliary power. Correction is made so that the power Pm decreases. The auxiliary power calculating unit 63 calculates the corrected power from the auxiliary power increasing unit 68 and the auxiliary power reducing unit 70,
The auxiliary power Pm corrected according to the road surface inclination is output.

FIG. 6 is a diagram showing the timing for determining the auxiliary power. FIG. 3 shows the vehicle speed V, the pedaling force Ta, the auxiliary power Pm by the motor, and the detection and calculation timings thereof. The detection output of each sensor is read from when the minimum value of the pedaling force Ta is detected until the next time the pedaling force Ta becomes the minimum value. Then, when the pedaling force Ta becomes the minimum value, the next calculation of the auxiliary power Pm is started based on the detection values of the respective sensors at that time. When the pedaling force Ta becomes the minimum value, the vehicle speed V is detected, and the difference ΔV from the previous vehicle speed is detected.
Is calculated. For example, at timings t1, t2, and t3,
The calculation of the auxiliary power Pm and the calculation of the vehicle speed difference (V-V-1) are performed. Also, the energization duty for obtaining the auxiliary power Pm calculated at the timings t1, t2 and t3 is instructed at timings t1 ', t2' and t3 ', respectively.

FIG. 7 is an output control circuit diagram of the motor 14, and FIG. 8 is a diagram showing energization timing and energization duty. In FIG. 7, a full-wave rectifier 71 includes FETs (generally, individual switching elements) 71a, 71b, 71c, 71d, 7e, connected to a three-phase stator coil 39.
71f, and the FETs 71a to 71f
2 is energized. The energization duty is set by the duty setting unit 73 based on the instruction supplied from the motor torque calculation unit 64 and is input to the driver 72.

At the drive timing for applying the auxiliary power Pm, the duty setting
The driver 72 supplies the current from the battery 17 by energizing the FETs 71 a to 71 f in accordance with the duty. On the other hand, when the regenerative output is generated, the electrical angle is 180 degrees from the drive timing.
At the regenerative timing shifted by a degree, the energization duty is supplied from the duty setting unit 73 to the driver 72,
The driver 72 follows the conduction duty according to the FET 71
a to 71f are energized. FET 71a at regenerative timing
To 71f are energized, the current generated in the stator coil 39 is rectified by the FETs 71a to 71f,
7.

Whether the drive timing or the regenerative timing is determined by the torque determining unit 74 based on the required motor torque T supplied from the motor torque calculating unit 64. When the required value T of the motor torque is positive, the energizing timing is set to the drive timing, and when the required value T of the motor torque is negative, the energizing timing is set to the regenerative timing.

In FIG. 8, the FETs 71a to 71f are energized by setting the conduction angle to an electrical angle of 120 degrees. The figure shows
This shows the energization timing at the drive timing. At the regenerative timing, the high-side FETs 71a, 71c, 71e are shifted by 180 electrical degrees from the drive timing.

FIGS. 9 and 10 are flowcharts of the main part of the process for generating the auxiliary power according to the actual running resistance. In the figure, in step S1, the vehicle speed V is calculated based on the detection output of the motor rotation sensor 49. In step S2, a flat-land running resistance R1 of an electric assisted bicycle (hereinafter, referred to as an "assisted vehicle") and a flat-land running resistance Rr of a normal bicycle (light vehicle) are calculated based on the vehicle speed V. For example,
When a light vehicle having a vehicle weight of 12 kg is driven by a person weighing 55 kg, the standard flat road running resistance Rr is used.

The flat-land running resistances R1 and Rr can be retrieved from a preset map. FIG.
Is a map showing an example of the relationship between the vehicle speed V and the level ground running resistances R1, Rr. The drawing shows a flat road running resistance R1 of an assist vehicle and a flat road running resistance Rr of a normal bicycle.
Are shown as functions of the vehicle speed V. By applying the vehicle speed V to this map, the flat road running resistance R1 of the assist vehicle and the flat road running resistance Rr of the normal bicycle can be obtained.

Returning to FIG. 9, in step S3, the difference (V-V-1) between the vehicle speed V-1 detected last time and the vehicle speed V detected this time.
To calculate the vehicle speed change amount ΔV (deceleration when the value is negative). In step S4, the pedaling force Ta is obtained from the detection output of the pedaling force sensor 47 and the crank rotation sensor 48, respectively.
And the crank rotation speed NCR. In step S5, the output of the pedaling force proportional to the pedaling force Ta and the function of the crank rotation speed NCR, that is, the motor torque T0, is calculated by the following equation (Equation 2). Motor torque T0 = f (Ta, NCR) ...
(Equation 2).

In step S6, the motor rotation sensor 49
, That is, the rotation speed Nm of the motor 14 is detected. In step S7, the previous motor torque T-1 is read from the previous value memory 61. In step S8, the total driving force Pw, that is, the total of the human power Ph and the auxiliary power Pm-1 is calculated by the following equation (Equation 3). Driving force Pw = (Ta × NCR × k1) +
(T-1 × Nm × k2) (Equation 3). Here, k1 and k2 are coefficients.

In step S9, the following equation (Equation 4) is used.
The actual running resistance Ra, which is a function of the driving force Pw, the speed change amount ΔV, and the vehicle speed V, is calculated. Actual running resistance Ra = f (Pw,
ΔV, V) (Equation 5). Specifically, the calculation of the actual running resistance Ra is based on a relation map of the driving force Pw, the speed change amount ΔV, and the actual running resistance Ra for each of the vehicle speeds V in a plurality of stages (for example, 5 k
m / hour), and this map can be searched and found. FIG. 12 shows the driving force Pw and the speed change amount Δ
5 is an example of a map in which the relationship between V and the actual running resistance Ra is set with a speed change amount ΔV as a parameter. In this figure, the flat running resistance R1 of the assist vehicle and the flat running resistance Rr of the normal bicycle are shown as functions of the vehicle speed V, respectively. Such a map is prepared for each of a plurality of vehicle speeds V. As described above, one cycle, that is, the crankshaft 2 is replaced with the driving force Pw.
Alternatively, the integrated value P · h of the total driving force for each one rotation may be used.

In step S10, the inclination of the road surface is determined, that is, whether the road is uphill or downhill. This determination can be made based on the value of the ratio between the actual running resistance Ra and the level running resistance R1 of the assist vehicle. For example, the value of the ratio (Ra / R1)
If the value is “5” or more, it is determined that the vehicle is going uphill, if “−1”, it is determined that the vehicle is downhill.

If it is determined that the vehicle is going uphill, the process proceeds to step S11, and the flag F1 indicating that the vehicle is going downhill is cleared. In step S12, it is determined whether a flag F0 indicating an uphill is set, and if this is affirmative, the flow proceeds to step S23 (FIG. 10). If step S12 is negative, the coefficient K is set to "1.2" in step S13. By increasing the coefficient K, as will be described later, the auxiliary power Pm decreases, and the driver can feel that the vehicle is approaching an uphill.

In step S14, the counter value n is incremented. In step S15, it is determined whether or not the counter value n has become "5". If the counter value n becomes "5", the counter value n is determined in step S16.
Is cleared, the flag F0 is cleared, and step S
23 (FIG. 10) for calculating the inclination correction value (FIGS. 15 and 16).
Will be described later). If the counter value n is not "5", the process proceeds to step S24 (FIG. 10).

On the other hand, if it is determined that the vehicle is going downhill, step S
Proceeding to S17, the flag F0 indicating the upward slope is cleared. In step S18, it is determined whether or not a flag F1 indicating a downhill is set, and if this is affirmative, the flow proceeds to step S23 (FIG. 10). Step S18
Is negative, the coefficient K is set to "0.8". Coefficient K
By reducing the auxiliary power Pm as described later.
And the driver can feel that the vehicle has gone downhill. In step S20, the counter value m is incremented. In step S21, it is determined whether or not the counter value m has become "3". If the counter value m becomes "3", the counter value m is set in step S22.
Is cleared, the flag F1 is cleared, and step S
Proceed to 23. If the counter value m is not "3", the process proceeds to step S24 (FIG. 10). Step S10
If it is determined that is a flat ground, the process proceeds to step S24 without performing the processing of the coefficient K, the counter values m, n, and the like.

In FIG. 10, in a step S24, it is determined whether or not the brake switch is on. If the brake switch has been turned on, the coefficient K is multiplied by a constant "1.2" in step S25, and the process proceeds to step S26. The multiplication of this coefficient K increases the regenerative output as described later. If the brake switch is not on, step S
The process skips Step 25 and proceeds to Step S26. Step S
At 26, the coefficient K is multiplied by the normal bicycle running resistance Rr. In step S27, the following equation (Equation 6) is used.
Calculate the auxiliary power Pm. Auxiliary power Pm = Ra-Rr (Equation 6).

As can be understood from the above equation (6), the auxiliary power Pm decreases when the flat running resistance Rr of a normal bicycle is large, and increases when the flat running resistance Rr is small. Since the flat ground running resistance Rr is multiplied by the coefficient K in step S26, the coefficient K changes the auxiliary power Pm. Therefore, when it is determined that the vehicle is traveling uphill and the coefficient K is set to “1.2” (step S13),
During the period until the counter n reaches the predetermined value "5", the auxiliary power Pm becomes small, and the driver feels an increase in the load. On the other hand, if it is determined that the vehicle is going downhill and the coefficient K is set to “0.8” (step S19), the auxiliary power Pm increases until the counter m reaches the predetermined value “3”. The driver feels a decrease in the load.

When the coefficient K is increased in step S25, the regenerative output increases for the following reason. That is, in a situation where the brake is applied, the total driving force Pw is small, and the actual running resistance Ra is also a negative value. Therefore, by increasing the coefficient K to increase the running resistance Rr, the negative value of the actual running resistance Ra is further increased in the process of step S27, and the regenerative output is increased. Thus, at the time of the brake operation, braking can be effectively performed by regenerative braking by the motor 14.

In step S28, a motor torque T which is a function of the auxiliary power Pm and the motor speed Nm is calculated by the following equation (Equation 7). Motor torque T = f (Pm, Nm) ...
(Equation 7).

The motor torque T may be changed as follows. In step S29, the motor torque T0 is added to the motor torque T in proportion to the pedaling force. With this change, light driving can be performed in the entire traveling area.

In step S30, the energization timing of the motor 14 is controlled. If the calculated motor torque T is positive, the control element (FET) of the full-wave rectifier 71 for controlling the motor 14 is energized at the time of driving. On the other hand, if the calculated motor torque T is negative, the motor 14
The control element (FET) for controlling the power supply is energized at a timing for regeneration. That is, the electrical angle is 18
Set a timing shifted by 0 degrees. In step S31, the energization duty is determined based on the absolute value of the motor torque T.

In step S32, it is determined whether or not the vehicle is on a downhill and the vehicle speed V is a predetermined low speed (for example, 5 km / hour or less). If this determination is negative, the process proceeds to step S33, and the settings in steps S26 and S27 are output to the motor 14. That is, when it is determined that the vehicle is in the down-push-walking state, the energization control of the motor 14 is not performed, and therefore, no regenerative control output is generated.

Step S29 can be modified as follows. In the modification of FIG. 13, in step S34,
It is determined whether or not the vehicle is on a flat ground, and if the vehicle is on a flat ground, the motor torque T0 corresponding to the pedaling force is added (step S35). Also,
Instead of step S35, the motor torque T can be replaced with the motor torque T0 corresponding to the pedaling force as in step S36. Thus, on a flat ground, the vehicle can be operated with the auxiliary power Pm proportional to the pedaling force.

Step S29 can be modified as follows. In the modification of FIG. 14, in step S37, it is determined whether or not the vehicle speed V is a predetermined low speed (for example, 5 km / hour or less). If it is determined that the vehicle speed V is low, the motor torque T0 is proportional to the pedaling force. (Step S3)
8). Also, instead of step S38, as in step S39, the motor torque T is changed to the motor torque T0 corresponding to the pedaling force.
Replace with Thereby, for example, at the beginning of rowing, auxiliary power is obtained by the motor torque T proportional to the pedaling force.

Next, a specific example of step S23 will be described. In step S23, the coefficient K is corrected so as to match the inclination of the traveling road. First, an example of uphill correction will be described. FIG. 15 is a diagram illustrating a value of a coefficient K corresponding to the vehicle speed V when traveling on an uphill. FIG. 3A shows an example in which the vehicle speed change per second is less than 3 km / h, and FIG.
km / h or more. Note that the initial value of the coefficient K is “1.0”. In FIG. 15A, when the vehicle speed V is low (for example, 5 km / h or less), such as at the start of rowing, the coefficient K is reduced and the auxiliary power Pm is increased. And
After the vehicle speed V has increased, the coefficient K is returned to the initial value.

In FIG. 15B, when the vehicle speed V is low (for example, 5 km / h or 10 km / h), the coefficient K
And the auxiliary power Pm is increased. Then, as the vehicle speed V increases, the coefficient K is gradually returned to the initial value. That is, during acceleration, the auxiliary power Pm is not suddenly reduced, but is maintained at a large value until the vehicle speed V increases to some extent (for example, 20 km / hour). In addition, the example of correction of traveling uphill can be applied to traveling on flat ground.

Next, an example of downhill correction will be described. FIG. 16 is a diagram illustrating a value of a coefficient K corresponding to the vehicle speed V when traveling on a downhill. The initial value of the coefficient K is “1.0”. Figure 1
In step 6, when the vehicle speed V is low (for example, 15 km / h or less), such as when starting to row on a downhill, the coefficient K is reduced to reduce the regenerative output. When the vehicle speed V increases, for example, between 15 km / h and 20 km / h,
The coefficient K is increased in proportion to the increase in the vehicle speed V, and the regenerative output is gradually increased. When the vehicle speed V further increases, the coefficient K is rapidly (for example, quadratic) until the vehicle speed V increases to some extent (for example, 25 km / hour).
Enlarge. As a result, the regenerative output sharply increases, and the vehicle speed V is rapidly limited.

[0075]

As is apparent from the above description, according to the first to sixth aspects of the present invention, the auxiliary power can be generated without depending on the periodic change of the pedaling force, so that the speed of the vehicle is extremely stable. And an appropriate auxiliary power can be given according to the road surface inclination.

In particular, according to the invention of claim 2, the actual running resistance is detected each time from the driving state of the vehicle, and the auxiliary power can be generated with high accuracy. Claims 3 and 4
According to the invention, the vehicle can be driven with the same feeling as when the vehicle is traveling on level ground.

According to the fifth and sixth aspects of the present invention, the driver can drive while feeling the change in the inclination of the road surface. In particular, according to the invention of claim 5, the electric assisted bicycle can be driven with a running feeling similar to that of a normal bicycle.
According to the invention, the inclination of the road surface can be determined by the actual running resistance detecting means without providing the inclination sensor.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a main part of a control device according to an embodiment of the present invention.

FIG. 2 is a side view of the electric assist bicycle including the control device according to the embodiment of the present invention.

FIG. 3 is a sectional view of a motor.

FIG. 4 is a diagram showing a relationship between a change in road surface condition and a change in driving force.

FIG. 5 is a block diagram showing a control function of auxiliary power at the start of a slope.

FIG. 6 is a timing chart showing a timing of determining an auxiliary power based on a vehicle speed and a pedaling force.

FIG. 7 is a control circuit diagram of a motor.

FIG. 8 is a timing chart showing motor control timing.

FIG. 9 is a flowchart (part 1) of a main part of a process of generating auxiliary power according to actual running resistance.

FIG. 10 is a flowchart (part 2) of a main part of a process of generating auxiliary power according to actual running resistance.

FIG. 11 is a map showing a relationship between a vehicle speed and a level ground running resistance.

FIG. 12 is a diagram showing an example of a map for searching for actual running resistance based on a vehicle speed change amount and a driving force.

FIG. 13 is a flowchart according to a modified example of step S29.

FIG. 14 is a flowchart according to another modification of step S29.

FIG. 15 is a diagram (part 1) illustrating a relationship between a correction coefficient of an auxiliary power and a vehicle speed.

FIG. 16 is a diagram (part 2) illustrating a relationship between a correction coefficient of an auxiliary power and a vehicle speed.

FIG. 17 is a cross-sectional view of a main part of a human-powered driving unit including a treading force detection device.

18 is a view as viewed in the direction of arrows AA in FIG. 17;

FIG. 19 is an enlarged sectional view of the treading force detecting device. .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Body frame, 5 ... Seat post, 8 ... Steering handle, 9 ... Brake lever, 14 ... Motor, 1
7 ... battery, 22 ... crankshaft, 24 ... pedal,
27: Chain, 32: Wheel hub, 35: Magnet, 37: Stator support plate, 39: Stator coil, 41: Magnetic pole sensor, 43: Substrate, 47: Tread force sensor, 48: Crank rotation sensor, 49: Motor rotation sensor, 50: vehicle speed sensor, 59: vehicle speed change amount calculation unit, 62: running resistance calculation unit

Claims (6)

[Claims] 1. A control device for an electric assist bicycle, comprising: a human-powered driving system for transmitting a driving force by a human power to a rear wheel; and a motor driving system for transmitting a driving force by a motor to a rear wheel. A control device for a battery-assisted bicycle, comprising: running resistance detecting means for detecting running resistance; and control means for generating a driving force corresponding to the actual running resistance in the motor drive system. 2. A vehicle speed change amount detecting means for detecting a vehicle speed change amount during a scheduled period, and a driving force calculating means for detecting a total driving force of a driving force by a human power and a driving force by a motor given during the scheduled period. The control device for a battery-assisted bicycle according to claim 1, wherein the actual running resistance is calculated as a function of a vehicle speed change amount with respect to the total driving force. 3. The driving force according to claim 1, wherein the driving force generated by the motor drive system is controlled such that the actual running resistance of the vehicle substantially matches the running resistance of the vehicle when traveling on level ground. Control device for electric assisted bicycle. 4. The resistance when traveling on level ground is set to the resistance when traveling on a flat bicycle.
The control device for an electric assisted bicycle according to the above. 5. A road surface inclination determining means for determining that a change in the inclination of a traveling road surface has occurred, and a driving force generated by the motor drive system when it is determined that the traveling road surface has changed to an upward inclination. 5. The control device according to claim 1, wherein the control unit controls the driving force to be generated by the motor drive system to be increased for a predetermined period when the predetermined period is reduced and when it is determined that the traveling road surface has changed to a downward slope. The control device for an electrically assisted bicycle according to any one of the above. 6. The road surface inclination determining means, based on a value of a ratio between the actual running resistance and a predetermined level running resistance, when the value of the ratio is larger than a predetermined value, the uphill slope, and the value of the ratio is 6. The control device for an electrically assisted bicycle according to claim 5, further comprising means for judging that the vehicle is going downhill when the vehicle speed is smaller than the predetermined value.