JPH09290794A - Assist force controller for electric power assisted vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assist force controller by which control with a better feeling can be carried out within a prescribed assist ratio, a power feeling is provided, and improvement in the feeling is accomplished without any increase in an electric current consumption of a battery (power source). SOLUTION: An assist power controller is provided with an input driving system 75 supplying a pedal pressing force to a driving wheel 32, an electric power driving system 40 supplying an assist force from an electric motor 44 to the driving wheel 32, and an assist force controlling means 54 variably controlling the assist force according to input torque to a crankshaft 46 and a vehicle speed, and by means of the assist force controlling means 54, a virtual pressing force Pi complying with a changing condition of the pedal pressing force P is found, and the assist force is controlled in compliance with the virtual pressing force Pi.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary force control device for an electric power assisted vehicle, which includes a human power drive system for supplying pedal effort to drive wheels and an electric power drive system for supplying auxiliary force to drive wheels.

[0002]

2. Description of the Related Art Conventionally, in an electric power assisted vehicle of this kind, for example, a bicycle with an assisted power, the assisted power from the electric power drive system is controlled according to the pedaling force and the vehicle speed input to the crankshaft. There is. In this case,
Generally, the ratio of the pedal effort (auxiliary ratio) is set to a constant value (about 1.0) below a predetermined vehicle speed, and becomes smaller as the vehicle speed becomes faster than this.

[0003]

However, in the above-mentioned conventional assisting force control device, since the assisting ratio is a constant value,
It was not possible to meet various requests for a feeling of assistance based on differences in leg strength and physical strength of the user. For example, there is a responsive auxiliary feeling that the assisting force increases more directly with an increase in the pedaling force, or when the pedaling force is large, that is, when the burden of human power is large, the assisting force is larger and smaller when it is smaller. In some cases, a supportive feeling with a smooth effect, such as assisting, is preferred, but it is not possible to control the assisting force to obtain such various assisting feelings.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide an auxiliary force control device for an electric power assisted vehicle that can meet a variety of requests for auxiliary feeling. .

[0005]

According to a first aspect of the present invention, there is provided a human power drive system for supplying a pedal effort to a drive wheel, an electric power drive system for supplying an assist force from an electric motor to the drive wheel, a pedal effort and a vehicle speed. In the auxiliary force control device for an electric power assisted vehicle that includes an auxiliary force control unit that variably controls the auxiliary force according to the above, the auxiliary force control unit obtains a virtual pedaling force according to a change state of the pedaling force, It is characterized in that the assisting force is controlled according to the virtual pedaling force.

According to a second aspect of the present invention, in the first aspect, the virtual pedal force is obtained by correcting the pedal pedal force with a time differential value of the pedal pedal force.

The invention of claim 3 is characterized in that, in claim 1, the virtual pedal force is obtained by correcting the pedal pedal force at an angular position of the pedal.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are views for explaining an auxiliary force control device for a bicycle with auxiliary power according to an embodiment (first embodiment) of the invention of claims 1 and 2.
Is a side view of the bicycle, FIG. 2 is a block diagram showing a configuration of the auxiliary power control device, and FIG. 3 is a diagram showing virtual pedal force.

In FIG. 1, reference numeral 1 is a bicycle with auxiliary power, and a body frame 10 of the bicycle 1 is a head pipe 1.
2, a down tube 14 extending obliquely downward and rearward of the vehicle body from the head pipe 12, a seat tube 16 standing upward from a rear portion of the down tube 14, and left and right extending rearward from a rear end portion of the down tube 14. It is provided with a pair of chain stays 20 and 20, and a pair of left and right seat stays 22 and 22 for connecting the rear end portions of the chain stays 20 and 20 and the upper end portion of the seat tube 16.

At the lower end of the head pipe 12, the front wheel 2 is attached.
A front fork 24, which supports 8 and has a steering handle 26 fixed to the upper end, is pivotally supported to the left and right. A seat post 30a is inserted into the seat tube 16 so that its height can be adjusted, and a saddle 30 is attached to the upper end of the seat post 30a. Furthermore, a rear wheel 32 is rotatably mounted between the rear ends of the chain stays 20, 20, and a hub 34 of the rear wheel 32 has an internal transmission built therein. The speed sensor (see FIG. 2) 87 detects the vehicle speed from the rotational speed of the rear wheel 32. The vehicle speed may be indirectly detected from the rotational speed of the rotary shaft in the power unit 40 described later.

Reference numeral 40 denotes a power unit (electric power drive system) which is a power source of the bicycle with auxiliary power.
The power unit 40 includes a power case 42 and a vehicle body cover 41 that projects forward from the power case 42.
And a permanent magnet type DC electric motor 44 disposed therein. The power case 42 is the down tube 14
The electric motor 44 is mounted below the rear portion 14a, and the electric motor 44 is parallel to the rear portion 14a of the down tube 14.

A crankshaft 46 is inserted through the power case 42 in the vehicle width direction, and crank arms 48 are provided at both ends thereof.
A crank pedal 50 is attached to the crank arm 48 (only one is shown). As a result, a human power drive system 75 that transmits the pedaling force applied to the crank pedal 50 to the rear wheel 32 via the chain 52 is configured.

The pedaling force applied to the crank pedal 50 is detected by a torque sensor (see FIG. 2) 86 provided in the power case 42, and the output (auxiliary power) of the electric motor 44 is output from the controller 54. Is controlled as described below. The auxiliary power and the pedaling force are combined in the power case 42, and the resultant force is transmitted to the rear wheel 32 via the chain 52. The controller 54 that controls the output of the motor 44 is mounted inside the vehicle body cover 41 so as to be located below the front portion 14b of the down tube 14.

The head pipe 12 of the vehicle body frame 10
The main switch 56 and an insertion opening 63 for inserting a memory card (not shown) in which the ratio of auxiliary power / pedal depression force according to the rider's physical strength, preference, etc. are stored near the connection portion to
And are arranged. The main switch 56,
And the insertion opening 63 is the opening 41 formed in the vehicle body cover 41.
It is facing outward from a.

Reference numeral 64 indicates a nickel-cadmium battery which serves as a power source for the power unit 40. This nicad battery 64
Is a battery case in which a large number of battery cells (not shown) are connected in series and built in the case, and which is arranged in the space between the seat tube 16 and the front edge of the rear wheel 32. It is detachably accommodated in 60. The upper end of the battery case 60 has the left and right seat stays 22, 2 above.
The nickel-cadmium battery 64 is located between the two and protrudes upward, and the nickel-cadmium battery 64 is vertically attached and detached by passing between the left and right seat stays 22, 22.

The controller 54 includes a CPU 81,
A waveform synthesis circuit 82 connected to the CPU 81, a differentiation circuit 83 arranged in parallel with the waveform synthesis circuit 82, and a motor drive circuit 84 are provided. A pedaling force from a torque sensor 86 (pedaling force sensor) is input to the waveform synthesizing circuit 82 through an interface 85, and the CPU 8
The vehicle speed from the speed sensor 87 is input to the vehicle 1 through the interface 88. Further, the motor drive circuit 8
4 is connected to an electric motor 44, and the battery (nicad battery) 64 is connected to the electric motor 44.

The controller 54 includes a torque sensor 8
The pedal depression force detected in 6 is corrected by the differential value of the pedal depression force to obtain a virtual pedaling force according to the change state of the pedal depression force, and the auxiliary power corresponding to the vehicle speed detected by the virtual pedaling force and the speed sensor 87 is obtained. Then, the amount of current supplied to the motor 44 is controlled so as to obtain the auxiliary power.

The virtual pedal force has the characteristics shown in FIG.
That is, the virtual pedaling force Pi shown in FIG. 3C is obtained by differentiating the pedaling force P shown in FIG. 3A with the pedaling force P shown in FIG. ) Is obtained by adding at an arbitrary ratio so that the areas become equal. However, it is also possible to change this addition ratio if necessary.

As is apparent from FIG. 3, the differential value i is positive on the rising side of the pedal effort P, while Pma
Since it becomes negative after x, the virtual pedaling force Pi has a characteristic that it increases sharply on the rising side and decreases sharply in the latter half.

Then, the CPU 81 controls the assisting force / virtual pedaling force P.
i so that the auxiliary ratio is 1, that is, the electric motor 4
4 controls the current supply amount via the motor drive circuit 84 so that the auxiliary force having the same magnitude as the virtual pedaling force is output.

As described above, in the present embodiment, as shown in FIG. 3, the time differential value i is added to the pedal effort P to obtain the value shown in FIG.
So that the areas of (A) and (C) are equal to each other.
Since the assisting force corresponding to the virtual pedaling force Pi is generated, the assisting force is increased more when the pedaling force is increased, and is assisted less when the pedaling force is decreased. To be Also in this case, FIG.
Since the areas (A) and (C) of (1) are made equal to each other, the auxiliary force is supplied based on the virtual pedaling force obtained.
The current consumption of the battery does not increase as compared with the case where the actual pedaling force and the auxiliary force of 1: 1 are supplied.

In the above embodiment, the addition ratio of the pedal depression force P and the differential value i is set to 1: 1. However, this addition ratio is of course arbitrary, and various ratios can be selected by appropriately selecting this ratio. A feeling of assistance can be realized.

In the above-described embodiment, the virtual pedal force is obtained by correcting the pedal pedal force with the time differential value thereof, but various modified examples can be adopted for the method of obtaining the virtual pedal force.
For example, the angle θ from the top dead center of the crank pedal 50 (see FIG.
) Is detected, and the pedal depression force P is detected by the pedal angle θ.
You can also obtain the virtual pedaling force by correcting
This is the invention of claim 3.

4 and 5 show an embodiment (second embodiment) of the invention of claim 3. In the present embodiment, the angle θ detected by the crank angle sensor 89 is input to the CPU 81 via the interface 90. The CPU 81
Calculates the correction value i shown in FIG. 4 (B) based on the angle θ. The correction value i is set to be positive on the rising side of the pedal effort P (crank angle 0 to 90 °) and negative on and after Pmax (crank angle 90 to 180 °). Then, the correction value i is applied to the pedal effort P as shown in FIGS. 4 (A) and 4 (C).
Are added at an arbitrary ratio to obtain the virtual pedaling force Pi. Here, the virtual pedaling force Pi rapidly increases on the rising side of the pedaling force as shown in FIG. 4C, and sharply decreases in the latter half.

When the pedal effort is corrected by the crank pedal angle in this way, the same effects as those of the first embodiment are obtained, and since the control is performed according to the crank angle, the crank pedal 50 is moved to the top dead center. A large amount of force is exerted when stepping on the pedal, which matches the feeling of the person stepping on the pedal with high precision, and the feeling of assistance is even more natural and favorable.

[0026]

As described above, according to the invention of claim 1, according to the change state of the pedal effort, for example, in the invention of claim 2, the pedal effort is corrected by the time differential value of the pedal effort. According to the invention of claim 3, the virtual pedal force is obtained by correcting the pedal pedal force by the crank pedal angle, and the assist force is controlled in accordance with the virtual pedal force. There is an effect that it is possible to meet various requests for auxiliary feeling such as effective auxiliary feeling.

[Brief description of drawings]

FIG. 1 is a side view of a bicycle with auxiliary power provided with an auxiliary force control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of the auxiliary power control system of the first embodiment.

FIG. 3 is a diagram showing a virtual pedaling force in the assisting force control device of the first embodiment.

FIG. 4 is a diagram showing a virtual pedaling force of the auxiliary force control device according to a second embodiment of the invention of claims 1 and 3.

FIG. 5 is a block diagram of the device of the second embodiment.

[Explanation of symbols]

 1 Electric Bicycle with Auxiliary Power 32 Rear Wheel (Drive Wheel) 40 Electric Power Drive System 44 Electric Motor 46 Crank Shaft 54 Controller (Assistance Force Control Means) 75 Human Power Drive System P Pedal Foot Power Pi Virtual Foot Power i Time Differential Value

Claims (3)

[Claims] 1. A human power drive system for supplying a pedal effort to a drive wheel, an electric power drive system for supplying an assist force from an electric motor to a drive wheel, and an assist for variably controlling the assist force according to a pedal effort and a vehicle speed. In an auxiliary force control device for an electric power assisted vehicle including force control means, the auxiliary force control means obtains a virtual pedaling force according to a change state of the pedal pedaling force, and controls the auxiliary force according to the virtual pedaling force. An auxiliary force control device for an electric power assisted vehicle. 2. The auxiliary force control device for an electric power assisted vehicle according to claim 1, wherein the virtual pedaling force is obtained by correcting the pedaling force with a time derivative of the pedaling force. 3. The assist force control device for an electric power assisted vehicle according to claim 1, wherein the virtual pedal force is obtained by correcting the pedal force at the angular position of the pedal.