JP2002145168A - Vehicle with auxiliary power unit and control method thereof - Google Patents

Abstract

(57) [Summary] As a regenerative braking method for a vehicle with an electric power unit, a regenerative braking amount is determined in proportion to a lever operation amount, or a regenerative braking is performed so that the actual vehicle speed follows a desired vehicle speed. Although the braking amount has been operated, it is extremely dangerous because the vehicle is suddenly braked downhill. SUMMARY OF THE INVENTION An object of the present invention is to realize safe regenerative braking without the need to operate a lever or the like. SOLUTION: A step S1 for detecting a manual driving force of a vehicle running unit, a step S3 for detecting a speed of the vehicle running unit and a step S4 for detecting an acceleration, and the vehicle running unit is determined from the detected manual driving force, speed and acceleration. Of calculating the running resistance of the vehicle S5
By applying a regenerative braking force to the auxiliary power drive unit when the calculated running resistance is a negative value, a troublesome operation of a lever or the like is not required, and safe regenerative braking is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle with an auxiliary power unit that is driven using human power and auxiliary power of an auxiliary power unit, and a control method therefor.

[0002]

2. Description of the Related Art In recent years, a known driving device such as an electric motor is provided as an auxiliary power device, and the auxiliary power from the auxiliary power device is applied to the human or human driving force of an operator or a user to drive and drive the vehicle. A vehicle with an auxiliary power unit is known. Specifically, for example, an auxiliary power generated by driving an electric motor is added to a pedal depressing force (rotational force) generated by an operator depressing a pedal, or a rotational force generated by turning a hand rim, and a wheel is driven. There is a bicycle with an electric motor, a wheelchair with an electric motor, or a luggage carrier that rotates and runs.

[0003] Even in such a vehicle with an auxiliary power unit, when decelerating on a downhill, a system of mechanically restraining wheels is generally used. In such a method, the potential energy is consumed by the heat generated in the wheel restraint portion, and the potential energy does not return to the battery or the like of the auxiliary driving device. Therefore, a current reverse to that of the case where the motor is normally assisted (a phase-reversed current in the case of an AC motor, hereinafter referred to as a regenerative current) is caused to flow, and the motor is operated to generate electric power.
It is conceivable to use regenerative braking (brake). In regenerative braking, the battery is charged because regenerative current returns to the battery. As a result, energy saving is realized, and even with the same battery capacity, it becomes possible to dramatically increase the traveling distance with the auxiliary power enabled compared to the case where regenerative braking is not used.

As an example of using a regenerative braking in a conventional vehicle with an auxiliary power unit, as disclosed in Japanese Patent Application Laid-Open Nos. 9-254861 and 10-81290, an operation of a lever for operating a braking force is disclosed. In some cases, the regenerative braking amount is determined in proportion to the amount, or the regenerative braking amount is operated so that the actual vehicle speed follows the desired vehicle speed.

Another invention is disclosed in Japanese Patent Application No. Hei 10-14771.
In the invention described in Item 50, there is a device that detects running resistance of a vehicle with an auxiliary power device and provides the vehicle with auxiliary power corresponding to the detected running resistance when the running resistance is positive (uphill).

[0006]

However, in the vehicle with an auxiliary power unit described in Japanese Patent Application Laid-Open No. 9-254861, the amount of regenerative braking is proportional to the amount of operation of a lever (brake lever) for operating the braking force. Therefore, the driver needs to be consciously applying braking, and braking is not automatically applied as in the case of an engine brake of an automobile. In other words, when a person does not operate the lever on a downhill, regenerative braking does not act on the vehicle, and the consumption of the battery cannot be reduced.

Further, since the operation lever (brake lever) serves both as a switch for regenerative braking and a brake lever for mechanical braking, mechanical braking may be operated earlier than regenerative braking. In this case, the regenerative braking force becomes insufficient, the heat loss due to mechanical braking becomes unnecessarily large, and the amount of regenerative current decreases accordingly, which is disadvantageous for extending the traveling distance.

In the vehicle with an auxiliary power unit described in Japanese Patent Application No. 10-81290, a method of applying a regenerative braking force to the vehicle when the operation lever (brake lever) is not operated is described.

FIG. 6 shows a flowchart of this method.
First, parameters such as a target vehicle speed set by a person are initially set (100), and thereafter, a signal voltage of a motor, a braking signal, and a target vehicle speed are read (102). Next, it is determined whether the brake is operated by the operation lever (104). If the brake is not operated, the difference ΔV between the target speed and the actual speed is determined.
Is calculated (106). The motor torque is searched based on the obtained difference ΔV (108), and a positive torque or a negative torque (regenerative braking) is generated in the motor based on the searched value (112). If the brake is operated, a search is made for a negative torque corresponding to the grip amount of the lever (11).
0).

In this method, when a person releases the operation lever from operation, that is, when regenerative braking is activated,
When the difference between the target speed and the actual speed of the vehicle is very large, the vehicle speed difference ΔV becomes very large. In such a case, as shown by 108, the motor torque value generated in the motor becomes a negative MAX value, and regenerative braking is suddenly applied to the vehicle, which is extremely dangerous.

Further, in this method, when a person wants the vehicle to run at a speed lower than a set target vehicle speed (before stopping the vehicle, etc.).
If the brake is not operated by the operation lever, the vehicle speed is adjusted to the set target vehicle speed, so that it is difficult to maintain the actual vehicle speed of the vehicle at the target vehicle speed or less, which may be dangerous.

In the invention described in Japanese Patent Application No. 10-147150, an auxiliary power corresponding to the running resistance is applied to the vehicle only when the running resistance is a positive value (uphill). Only the mechanical braking reduces the speed of the vehicle, and regenerative braking by the electric motor is not performed, so that the consumption of the battery cannot be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a safe regenerative braking force of an electric motor is determined from a human driving force and the acceleration and speed of a vehicle. The purpose is to realize regenerative braking and to reduce battery consumption.

[0014]

In order to achieve the above object, a vehicle with an auxiliary power unit according to the present invention includes a step of detecting a manual driving force of a vehicle traveling unit, and a step of detecting a speed of the vehicle traveling unit. Calculating the acceleration from the detected speed; calculating the running resistance of the vehicle running unit from the detected manual driving force and speed and the acceleration; and when the calculated running resistance is a negative value. A first regenerative braking force corresponding to a running resistance is applied to the auxiliary power drive unit.

Further, when the speed V of the vehicle running section is equal to or higher than a desired speed V0, the auxiliary power drive section applies a first regenerative braking force corresponding to the running resistance and a speed difference V-V0. It may be applied together with the second regenerative braking force.

A vehicle running unit for running the vehicle, a manual driving unit for applying a manual driving force to the vehicle running unit, an auxiliary power driving unit for providing an auxiliary power to the vehicle running unit by an electric motor, A human-powered driving force detection unit that detects a force, a speed detection unit that detects the speed of the vehicle traveling unit, and a calculation unit that calculates the traveling resistance of the vehicle traveling unit from the detected human-powered driving force, speed, and the acceleration. A control unit that applies a first regenerative braking force to the auxiliary power drive unit in accordance with the running resistance when the calculated running resistance is a negative value. .

Further, when the speed V of the vehicle running portion is equal to or higher than a desired speed V0, the second regenerative braking force corresponding to the first regenerative braking force and the speed difference V-V0 is applied to the auxiliary power driving portion. May be provided by the control unit.

With this configuration, the vehicle with the auxiliary power device automatically adjusts the regenerative braking force without operating the operation lever or the like in a running vehicle. Therefore, a safe control method for a vehicle with an auxiliary power device can be realized because the vehicle does not participate in the vehicle. Further, since the regenerative braking is automatically controlled, the braking force of the mechanical brake and the operation frequency can be significantly reduced, and the consumption of the battery can be suppressed.

[0019]

1 to 5 show an embodiment of the present invention.

(Embodiment 1) FIG. 1 is a structural view showing a schematic structure of an electric assisted bicycle which is a vehicle with an auxiliary power unit, and FIG. 2 shows a control means of the vehicle with an auxiliary power unit shown in FIG. FIG.

As shown in FIG. 1, the vehicle with an auxiliary power unit according to the present embodiment has a vehicle running unit 1 for running the vehicle, a human-powered driving unit 2 for driving the vehicle running unit 1, and an electric power drive. A control unit 4 for controlling the unit 3 and the electric power drive unit 3 is provided.

The vehicle traveling section 1 includes wheels 1a, 1b for traveling the vehicle in contact with a road surface, and support mechanisms 1c, 1d for rotatably supporting the wheels 1a, 1b, respectively. The wheel running unit 1 is supplied with the manual driving force from the manual driving unit 2 and the electric power from the electric power driving unit 3 driven by the power supply 4a, whereby the wheels 1b rotate and the vehicle runs.

The human-powered driving unit 2 includes a pedal 2a for receiving human power such as an operator and a user, and a crankshaft 2b for transmitting the human power to the vehicle traveling unit 1 as a human-powered driving force.
And a transmission mechanism 2c such as a chain.

As shown in FIG. 2, the electric power drive unit 3 includes a drive device such as an electric motor 6 which is an electric motor, and operates (rotates) by passing a current from the control unit 4. Further, the electric power drive unit 3 uses the rotational force as electric power to drive the vehicle traveling unit 1 via the reduction gear 5 and the transmission mechanism 2c (FIG. 1).
To communicate. The electric motor 6 includes a speed detector 10 and sequentially outputs the motor rotation speed to the controller 4.

The control unit 4 includes a human driving force detection sensor 7 for detecting the human driving force transmitted from the human driving unit 2 to the vehicle traveling unit 1, and the output of the human driving force sensor 7 and the speed detection unit 1
A control circuit 8 for instructing a drive current of the motor from a vehicle acceleration obtained by calculating a rotation signal of the motor obtained from 0, a motor drive circuit 9 for supplying a current to the motor in accordance with the current instruction, and an electric power for each circuit of the control unit Power supply 4a
It has.

Next, a control method for a vehicle with an auxiliary power unit according to this embodiment will be described with reference to FIG.
FIG. 3 is a flowchart illustrating the control of the control means of the vehicle with the auxiliary power device of FIG. As shown in FIG.
In the vehicle with the auxiliary power unit according to the present embodiment, first, the human-powered driving force detecting unit sensor 7 detects
Is detected (Step S)
1). The detected manual driving force Th is multiplied by the auxiliary power ratio kh to calculate an auxiliary force current command Ih to be applied to the electric motor as auxiliary power for assisting the manual driving force (step S2). Ih = kh × Th / ki (1) where ki is a torque constant of the motor.

Next, the motor peripheral speed ω detected by the speed detector 10 is added to a coefficient k in consideration of the reduction ratio of the speed reducer, the wheel diameter, and the like.
The vehicle speed v is calculated by multiplying by v (step S3). V = kv × ω (2) Then, a vehicle acceleration α is calculated by differentiating the vehicle speed V (step S4). α = d / dt × V (3) Next, the running resistance g (θ) due to the road surface inclination of the vehicle is calculated (step S5). The equation of motion of the electric bicycle can be expressed as follows. M × α + D × V = Fh + Fm−g (θ) (4) where Fh is the vehicle driving force by human power, Fm is the vehicle driving force by motor assistance, M is the weight of the bicycle and human, D is the coefficient of friction of the road surface, θ represents the inclination of the road surface. Here, the coefficient of friction D of the road surface is a resistance coefficient indicated on page 65 of “The concept of dynamics (issued by Iwanami Shoten on June 8, 1993)”.

The vehicle driving force (human force) Fh by human power,
The vehicle driving force Fm assisted by the motor can be expressed as follows. Fh = kfm × Th (5) Fm = kfm × ki × Im (6) Here, kfm is a coefficient for converting human driving force into vehicle driving force, kfm is a coefficient for converting motor torque into vehicle driving force, and Im is a coefficient. Motor current. From the equations (4) to (6), the running resistance g (θ) due to the road surface inclination can be calculated as follows. Here, θ is conceptually an angle with respect to the vehicle traveling plane, but the actual vehicle traveling resistance may not coincide with the actual angle because external force such as wind is applied. g (θ) = Fh + Fm−M × α−D × V = kfh × Th + kfm × ki × Im−M × α−D × V (7) The running resistance g (θ) calculated by the equation (7) becomes negative. In this case, the force for accelerating the vehicle is applied from equation (4). That is, it can be determined that the vehicle is traveling down a slope (step S6). When g (θ) is positive, I obtained by equation (1)
h is used as it is as the motor current command Icom (step S7).

Here, when g (θ) is negative,
By adding Ig obtained by converting g (θ) to a motor current value to the motor current command Icom, it becomes possible to cancel the running resistance due to the road surface inclination (step S7).
This makes it possible to travel with the same feeling as when traveling on level ground, even when going down a slope. Ig can be calculated as follows (step S8). Ig = g (θ) / (kfm × ki) (8) The motor current command Icom can be obtained from the equations (1) and (8) as follows (step S9). Here, kc is a cancellation coefficient for determining the degree of cancellation of the running resistance. Icom = Ih + kc × Ig (9) In the equation (9), when g (θ) is negative, Ig is always negative. Therefore, when the absolute value of Ig exceeds the absolute value of the auxiliary force current command Ih, The current command Icom becomes negative, and the motor performs regenerative braking. As a result, the negative running resistance is offset by the regenerative braking, so that the pedal can be pedaled on a downhill with the same feeling as on a flat ground. That is, since the assisting force current command Ih is proportional to the manual driving force Th as shown in the equation (1), even if a person stops pedaling on a downhill, rapid regenerative braking is performed on the vehicle. It is possible to travel safely without participating in the vehicle.

Further, since the regenerative braking is always controlled automatically, the braking force of the mechanical brake and the frequency of operation can be greatly reduced, and the consumption of the battery can be suppressed.

In this embodiment, the speed detecting section is constituted by detecting the motor rotation speed. However, the speed detecting section may be constituted by detecting the rotation speed of a wheel, a speed reducer, a crank or the like.

(Embodiment 2) In Embodiment 1, depending on the setting of the cancellation coefficient kc, there is a possibility that the speed of the vehicle may continue to increase on a downhill as in a normal vehicle without auxiliary power. Therefore, a method of controlling a vehicle with an auxiliary power device that does not keep increasing the speed of the vehicle will be described below.

FIG. 4 is a flowchart for explaining the control of the control means of the vehicle with the auxiliary power unit according to the second embodiment of the present invention. It is the same as the first embodiment except that the motor current command value is calculated using a monotonically increasing function relating to speed.

As shown in the flowchart of FIG. 4, the same control operation as in the first embodiment is performed from step 1 to step 7.

In step 6, if g (θ) is a negative value, that is, if the vehicle with the auxiliary power unit is going downhill, a monotonically increasing function f with respect to the vehicle speed V prepared in advance.
The value is calculated by (V) (step S8). Here, the function shown in the equation (11) will be described as an example, but another monotone increasing function may be used. f (V) = a (V−V0) ² (V> V0) 0 (V ≦ V0) (10) where a and V0 are constants that determine the characteristics of regenerative braking. FIG. 5 is a graph of this equation. Speed V
Is set to 0 up to V0, and if it exceeds V0, it increases in a quadratic curve.

The motor current command Icom is calculated from equations (1) and (10) (step S9). Icom = Ih−f (V) (11) From the equation (11), as the vehicle speed V increases, f
Since (V) becomes larger, if it becomes larger than the auxiliary force current command Ih, Icom becomes negative, a regenerative current flows, and regenerative braking becomes effective. That is, when the vehicle speed exceeds V0 and f (V) exceeds Ih on a downhill, regenerative braking is performed, and the regenerative braking force gradually increases as the vehicle speed increases. That is, even on a steep downhill, the vehicle speed is equal to the desired value V
When it exceeds 0, regenerative braking is automatically applied gradually to the vehicle,
Since the vehicle speed V can be suppressed without a sudden change in the braking force, safe regenerative braking of the vehicle can be realized on a downhill.

Further, since the regenerative braking is automatically controlled, the braking force of the mechanical brake and the operation frequency can be greatly reduced, and the consumption of the battery can be suppressed.

Here, the monotonically increasing function is shown by the equation f (V), but a table that monotonically increases with respect to the speed V may be used instead of the equation f (V).

Although f (V) is subtracted in equation (11) after judging a downhill, if equation (11) is applied irrespective of uphill or downhill, the speed limitation due to regenerative braking is also obtained. Available.

In the first and second embodiments, the running resistance is calculated from the human driving force and the speed of the vehicle to determine whether the vehicle is traveling downhill. The downhill may be determined using a gyro or the like.

Further, the motor current command Icom can be set as follows by combining the first and second embodiments. Icom = Ih + kc × Ig−f (V) (12) By obtaining the motor current command by the equation (12) and controlling the vehicle, a person can travel on a downhill with the same feeling as a flat ground. Furthermore, when the speed of the vehicle exceeds a desired speed, a braking force can be gradually generated in the vehicle, and a vehicle with an auxiliary power device that is safe and consumes less battery can be realized.

[0042]

As described above, according to the method for controlling a vehicle with an auxiliary power unit according to the present invention, the vehicle with the auxiliary power unit can automatically generate regenerative braking force without consciously operating an operation lever or the like. , And a vehicle with an auxiliary power device that is safe and does not impair ride comfort because regenerative braking is not suddenly applied to the vehicle, and a control method thereof can be realized.

Further, since the regenerative braking is automatically controlled, the braking force of the mechanical brake and the operation frequency can be greatly reduced, and the consumption of the battery can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a vehicle with an auxiliary power unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing control means of the vehicle with the auxiliary power unit according to the embodiment of the present invention.

FIG. 3 is a flowchart showing control of the vehicle with the auxiliary power unit according to the first embodiment of the present invention;

FIG. 4 is a flowchart showing control of a vehicle with an auxiliary power unit according to Embodiment 2 of the present invention.

FIG. 5 is a function f of monotonically increasing according to the second embodiment of the present invention;
Graph showing (V)

FIG. 6 is a flowchart showing control of a vehicle with a conventional auxiliary power unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vehicle running unit 2 human power drive unit 3 electric power drive unit (auxiliary power drive unit) 4 control unit 5 reduction gear 6 motor (electric motor) 7 human power drive force detection sensor 8 control circuit 9 motor drive circuit 10 speed detection unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H115 PA01 PA08 PG06 PG10 PU01 PV01 QE06 QI04 QN03 TB03 TB10 TO02 TO04 TO07 TO09 TO30

Claims (4)

[Claims] 1. An auxiliary power device comprising: a vehicle running unit for running; a human power driving unit for applying a manual driving force to the vehicle running unit; and an auxiliary power driving unit for applying an auxiliary power to the vehicle running unit by an electric motor. A method for controlling a vehicle with a vehicle, comprising: a step of detecting a manual driving force of the vehicle traveling unit; a step of detecting a speed of the vehicle traveling unit; a step of calculating an acceleration from the detected speed; Calculating the running resistance of the vehicle running unit from the human-powered driving force, the speed, and the acceleration; and, if the calculated running resistance is a negative value, the first regenerative braking system according to the running resistance to the auxiliary power drive unit. A method for controlling a vehicle with an auxiliary power unit, characterized by providing power. 2. The vehicle according to claim 1, wherein the speed V of the vehicle traveling portion is a desired speed V.
2. The auxiliary power according to claim 1, wherein when the value is 0 or more, a second regenerative braking force according to a speed difference V−V0 is applied to the auxiliary power drive unit in addition to the first regenerative braking force. 3. A control method for a vehicle with a device. 3. A vehicle drive unit for running, a human drive unit for applying a manual drive force to the vehicle travel unit, an auxiliary power drive unit for providing an auxiliary power to the vehicle travel unit with an electric motor, and the human drive unit. A human-powered driving force detection unit that detects a force, a speed detection unit that detects the speed of the vehicle traveling unit, and a calculation unit that calculates the traveling resistance of the vehicle traveling unit from the detected human-powered driving force, speed, and the acceleration. A control unit that applies a first regenerative braking force to the auxiliary power drive unit according to the running resistance when the calculated running resistance is a negative value. 4. The vehicle according to claim 1, wherein the speed V of the vehicle traveling unit is a desired speed V.
The auxiliary power unit according to claim 3, further comprising a control unit that applies a second regenerative braking force to the auxiliary power drive unit according to the first regenerative braking force and a speed difference V-V0 when the value is 0 or more. Vehicle.