JPH0781660A - Vehicle having electric motor - Google Patents

Abstract

PURPOSE:To generate always proper motor auxiliary force by measuring respectively a manpower in a cease period of motor auxiliary force and resultant force in an impression period, finding a target value of the auxiliary force to the manpower, and correcting the target value from a difference between it and an auxiliary force actual value when the auxiliary force is added. CONSTITUTION:A crank pedal is installed on a crank shaft 32 of a motive power unit containing a permanent magnet type DC electric motor 22, and rotation of a driving shaft 30 is transmittied to a rear wheel 14 through a one-way clutch 40 and an interior trim type speed change mechanism 42. In such a bicycle having the electric motor, manpower driving force in a cease period of auxiliary force and resultant force of the manpower driving force and the auxiliary force in an impression period are detected by a manpower-resultant force detecting means 50, and a target value of the auxiliary force corresponding to the manpower driving force is stored in a memory 68A. By an auxiliary force operation correcting means 68B, an actual value of the auxiliary force obtained by subtracting the manpower driving force from detected resultant force is compared with the target value, and the target value is corrected, and the auxiliary force is controlled by an electric power circuit 68C in order to make it coincide with a corrected target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a driving system by human power and a driving system by electric motor in parallel, and controls the driving force (assisting force) by the electric motor in approximately proportion to the driving force by human power. The present invention relates to a vehicle with an electric motor.

[0002]

2. Description of the Related Art It is known to detect driving by human power by, for example, pedaling force and control the driving force (that is, driving current) of an electric motor in accordance with the magnitude of the pedaling force by using a current-driving force characteristic stored in advance. (For example, the actual Kaisho 56-
76590, JP-A-2-74491, etc.). That is, when the burden of human power is large, the driving force of the electric motor is also increased to reduce the load of human power.

Further, the resultant force of human power and electric motor is detected,
A bicycle equipped with an electric motor in which the driving force (auxiliary force) of the electric motor is controlled by this resultant force has also been proposed (Actual Kaihei 4-127090). If the human power is Th and the driving force (assisting force) of the electric motor is Tm = kTh (where k is a constant coefficient), the resultant force Tp is Tp = Th (1 + k).
Becomes

However, in the first calculation, the resultant force Tp ₁ = Th
When (1 + k) is calculated, the resultant force Tp is calculated in the second calculation.
₂ is Tp ₂ = (Th + kTp ₁ ) = Th (1 + k + k
² ) Similarly, in the nth calculation, Tph = Th ×
Σk ^n-1 (where Σ represents the total sum from n = 0 to n = n). In order that this resultant force Tp does not diverge by repeating the calculation, it is necessary to set k <1. For example, when k = 1/2, Σ (1/2) ⁿ = 2, so Tpn = 2Th become.

[0005]

2. Description of the Related Art Generally, in an electric motor, it is inevitable that performance characteristics vary. Therefore, even if the current value is calculated so that the driving force of the electric motor matches the target value obtained from the pedaling force or the resultant force, the target motor driving force is accurate as long as this current / driving force characteristic changes for each motor. It's very difficult to get to.

Therefore, it is conceivable to detect the motor driving force and perform feedback control so as to match the target driving force. However, the above-described method of determining the motor driving force by detecting the pedaling force requires a sensor for the motor driving force in addition to the sensor for the pedaling force, which causes a problem that the number of sensors increases.

Also, in the case of detecting the resultant force, a sensor for obtaining the motor driving force or the pedaling force is required in addition to the sensor for the resultant force, and there is a similar problem.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and always provides a correct motor driving force regardless of variations in performance or characteristics of an electric motor, or even if the characteristics of the electric motor change with time. It is an object of the present invention to provide a vehicle equipped with an electric motor that can generate a noise and that does not increase the number of sensors.

[0009]

According to the present invention, an object of the present invention is to provide an electric drive system in which a human power drive system and an electric drive system are provided in parallel, and an auxiliary force by the electric drive system is controlled substantially in proportion to a driving force by the human power drive system. In a vehicle with a motor, a rest period and an application period of the auxiliary force are alternately provided periodically, and the human driving force is detected during the rest period, and a resultant force of the human driving force and the auxiliary force is detected during the applying period. Determined by subtracting the human power / force calculation means, a memory for storing the target value of the auxiliary force corresponding to the detected human power / driving force, and the human power / driving force detected by the human power / force detection means. And an assist force calculating / correcting means for comparing the actual value of the assist force with the target value to correct the target value, and electric power for controlling the assist force so that the assist force matches the corrected target value. Times Electric motorized vehicle, characterized in that it comprises the bets are achieved by.

[0010]

1 is a side view of an embodiment of the present invention, FIG. 2 is a power system diagram thereof, FIG. 3 is a block diagram showing functions of a controller thereof, FIG. 4 is a flow chart of its operation, and FIG. ,
FIG. 6 is a diagram schematically showing a motor applied voltage waveform.

In FIG. 1, reference numeral 10 is a main frame, which extends obliquely downward and rearward from the head pipe 12 to the rear wheel 1.
4 axles. A seat tube 16 is fixed so as to be substantially orthogonal to the main frame 10, and a seat post 20 supporting a saddle 18 is fixed to an upper end of the seat tube 16.

A tubular portion 16a which opens downward is formed in the lower portion of the seat tube 16, and a permanent magnet type DC electric motor 22 is housed in the tubular portion 16a. A power unit 24 is fixed to the lower end of the seat tube 16. The power unit 24 includes a bottom bracket case (hereinafter referred to as BB case) 26 and a rear stay 28 extending rearward from the BB case 26, and the rear wheel 14 is fixed to a rear end of the rear stay 28. A drive shaft 30 (see FIG. 2) is inserted into the right rear stay 28.

A crank shaft 32 is inserted through the BB case 26 of the power unit 24, and cranks 34 are fixed to both ends thereof. The crank 34 has a crank pedal 36,
36 is attached.

The left end of the axle 38 of the rear wheel 14 is fixed to an end plate 28a fixed to the left rear stay 28,
The right end of the axle 38 is fixed to a bevel gear case (not shown) fixed to the right rear stay 28. Axle 38
A hub (not shown) is rotatably held in the hub, and the rotation of the drive shaft 30 is transmitted to the hub via the bevel gear mechanism, the one-way clutch 40, and the internal speed change mechanism 42 (FIG. 2).

In the power unit 24, the rotation of the crank shaft 32 is transmitted to the drive shaft 30 via a one-way clutch 44 (FIG. 2).
Bevel gears (not shown) are installed inside. The rotation of the motor 22 is transmitted to the drive shaft 30 via the one-way clutch 46 and the speed reducer 48.

Drive shaft 30 or rear wheel 1 from drive shaft 30
A sensor (human force / result force detection sensor) 50 for detecting the driving force T applied to the drive shaft 30 is attached to the rotary drive system up to the position 4. The sensor 50 has, for example, a structure for detecting the twist of the driving force 30, and the driving shaft 3
The output of the strain gauge attached to 0 can be taken out through a slip ring or the like. Further, the driving reaction force may be detected by the planetary gear of the internal transmission mechanism 42 provided in the hub of the rear wheel 14 and this reaction force may be used as the driving force T.

In FIG. 1, 52 is a rechargeable battery such as a lead battery, 54 is a controller, and these are housed between the head pipe 12 and the seat tube 16 of the main frame 10.

The controller 54 controls the motor current by a chopper method. That is, the DC voltage is turned on / off at a frequency sufficiently higher than the rotation cycle of the crankshaft 32, and the duty ratio {= on time / (on time + off time)} is changed to continuously change the motor current / voltage. To control.

In FIG. 1, reference numeral 56 denotes a vehicle speed sensor for obtaining the vehicle speed S from the rotational speed of the drive shaft 30. The vehicle speed sensor 56 obtains the rotational speed of the rear wheel 14 using the rotational speed of the drive shaft 30 and the gear ratio of the speed change mechanism 42, and further calculates the vehicle speed S.

The driving force T detected by the human power / result force detection sensor 50 and the vehicle speed S detected by the vehicle speed sensor 56 are controlled.
The controller 54 calculates the motor current corresponding to the driving state based on the driving force T and the vehicle speed S. Then, the motor current is controlled so as to match the calculation result, and the motor output, that is, the assist force Tm is generated.

The controller 54 is constructed as shown in FIG. The motor 22 and the battery 52 form a closed circuit together with the switching circuit 60, and this closed circuit serves as the main circuit 62. The switching circuit 60 is composed of, for example, a MOS-FET. A flyhole diode 64 is connected in parallel to the motor 22, and a shunt 66 for current detection is used.
Are attached to the main circuit 62.

Reference numeral 68 denotes a CPU, which outputs a command value i for the assisting force Tm of the motor 22 based on the human power Th, the vehicle speed S, and the like. That is, the command value i is set so that the assisting force Tm of the motor 22 is periodically increased and decreased in synchronization with the periodic increase and decrease of the human power Th.
Is output. Further, when the vehicle speed S becomes constant, the assisting force Tm may be limited to limit the vehicle speed S.

The target value of the assisting force Tm with respect to the human power Th is stored in the memory 68 in advance. That is, Tm =
The assisting force coefficient k is stored in this memory 68A as k · Th. The calculation of the assisting force Tm is the assisting force calculation of the CPU 68 /
This is performed by the correction means 68B.

In practice, the assisting force should be changed according to the characteristics of the motor 22, so the assisting force calculating / correcting means 68B makes various corrections. When the target auxiliary force is appropriately corrected and obtained, the power circuit 68C obtains the duty ratio of the motor current and outputs the command value i for controlling the motor 22.

Reference numeral 70 denotes a gate circuit, which outputs a gate signal g for driving the switching circuit 60 in response to a command value i supplied from the CPU 68 in which the duty ratio changes. That is, when increasing the motor output T _M , the value (duty ratio) of (ON time) / (OFF time + ON time) of the command value i is increased.

Here, the gate signal g causes the motor applied voltage to alternate between a rest period t ₁ and an application time t ₂ at a constant cycle (for example, 20 to 30 H ₂ ) as shown in FIG. within ₂ to intermittently with a duty ratio which is substantially proportional to the depression force at a sufficiently high frequency (e.g. 16kH _Z). The gate signal g output by the gate circuit 70 based on the command value i is sent to the switching elements of the switching circuit 60 to selectively turn on / off each switching element.

In FIG. 3, reference numeral 72 is a main switch. When the main switch 72 is turned on, the CPU 68
Turns on the main relay 74 interposed in the main circuit 62, and also supplies the power supply unit 76, the auxiliary device control unit 78, and the gate circuit 7.
0, all other parts of the controller 54 are activated. The power supply unit 76 steps down the voltage of the battery 52 for traveling by using, for example, a switching regulator to generate the power supply voltage of the CPU 68, the drive voltage of the auxiliary device 80, and the like.

A small-capacity battery 82 other than the battery 52 may be connected to the power supply section 76. In this case, the battery 5
The voltage of 2 is stepped down by the switching regulator to charge the small capacity battery 82. The auxiliary device 80 includes a lamp and meters, which are driven by the electric power of the power supply part 76 according to a command from the auxiliary device control part 78.

Reference numeral 84 is a brake switch, which detects a brake operation and sends a brake signal to the CPU 68.
In the CPU 68, based on this brake signal, for example, the human power T
Even if h is a certain value or more, the assisting force Tm of the motor is set to 0 or limited.

The human power / result force detection sensor 50 is C
The driving force T is detected in synchronization with a synchronization signal c output from the PU 68 indicating the application time t ₂ of the command value i and the rest time t ₁ . Here, the driving force T detected at a certain time within the application time t ₂ of the command value i is the resultant force Tp of the human force Th and the motor assist force Tm.
The actual value of (= Th + Tm) is shown, and the driving force T detected at a certain time within the rest time t ₁ of the command value i shows the actual value of the human power Th.

As described above, since the resultant force Tp is detected within the application time t ₂ of the command value i and the human force Th is detected separately during the rest time t ₁ , one human force / result detection sensor 5 is used.
At 0, the human power Th and the auxiliary force Tm of the motor 22 (= Tp-T
h) and can be obtained.

Since the assisting force Tm generated within the application time t ₂ of the command value i is the human force Th obtained immediately before, the assisting force Tm within the application time t ₂ is constant.
However, while the human power Th is increasing (accelerating) and decreasing (decelerating), the human power Th after the human power Th is calculated by the sensor 50 is increasing or decreasing. Therefore, the correction coefficient α ₁ according to the acceleration / deceleration is stored in the memory 68A in advance, and when the assisting force Tm is calculated, this correction coefficient α ₁ is used for Th ′.
= Α ₁ Th, Tm ′ = (Tp−α ₁ Th).

The assisting force is obtained by Tm = k.Th (k is an assisting force coefficient stored in the memory 68A), and the assisting force Tm thus obtained changes due to changes in the characteristics of the motor 22 and the like. Therefore, the calculated target assist force Tm
Does not always match the actual assisting force Tm 'generated by the motor 22. Therefore, the assisting force coefficient k stored in the memory 68A is corrected using the actually obtained assisting force (actual value) Tm '. That is,

[0034]

[Number 1] Tm '= k'Th, Tm = kTh , Tm' = α 2 · Tm, = α 2 · kTh = k'Th ∴k '= α 2 · k

The correction coefficient α ₂ is obtained by
Remember. After that, these correction factors α ₁ , α
₂ and the correction factors α ₁ , α ₂
Will be corrected.

The above operation will be described with reference to FIGS.
First, at a certain duty ratio, the pause time of the command value i is t ₁ ,
The application time is set to t ₂ , and the time t ₃ from when the application time t ₂ is entered until the resultant force Tp is detected is set (step 100 in FIG. 4). When the command value i enters the resting cycle, the timer 1 is started and starts measuring the time T ₁ (step 10
2).

When timer 1 reaches time t ₁ (step 1
04), reset the timer 1 (step 106),
The human power Th is measured (step 108). The difference from the previously calculated human power Th is calculated (step 110), and the correction coefficient α ₁ described above is stored in the memory 68A according to whether acceleration or deceleration is in progress.
Then, the actual human power Th ′ is obtained from α ₁ Th (step 112). The manpower Th 'auxiliary force coefficient k for determined from the memory 68A (step 114), the auxiliary force Tm = KTH' determined by = K · α ₁ · Th (step 116).

When the command value i enters the application time t ₂ , the timer 2 starts and starts measuring the time t ₂ (step 1
18), the assisting force Tm is actually generated (step 12)
0). At the same time as the timer 2 is started, the timer 3 is also started to start measuring the time t ₃ (step 122). When the time t ₃ reaches the set value (step 124), the sensor 50
Measures the resultant force Tp (step 126) and resets the timer 3 (step 128).

After the application time t ₂ of the command value i ends, the timer 2
Becomes a set value (step 130), the timer 2 is reset (step 132), and the assisting force Tm disappears (step 134). At this time, the actual assisting force Tm 'is obtained as described above (step 136), and the correction coefficient α ₂
Then, the assisting force coefficient k'is obtained and stored in the memory 68A (step 138). This assisting force coefficient k'is used in the subsequent calculation. The above operation is repeated for each cycle of the command value i.

Although the human power is detected by the pedaling force in the above embodiments, it is needless to say that the driving force by the arm is detected when the present invention is applied to a hand-driven vehicle such as a wheelchair. It should be noted that the present invention includes one applied to a human power carrying device, and in this case, the indexing force by human power is detected. The vehicle of the present invention also includes a carrier vehicle or the like without a driver.

[0041]

As described above, according to the invention of claim 1, the human power is measured during the rest period of the motor auxiliary force and the resultant force is measured during the application period, and the auxiliary force for the human power obtained by using the data stored in the memory is obtained. Find the target value of. Then, the actual value of the assisting force is detected from the resultant force and human power obtained with this assisting force added, and the target value is corrected from the difference from the target value, so the characteristics of the electric motor are not uniform. Therefore, the correct motor assist force can always be generated regardless of the change over time. Further, since the human power is obtained from one sensor and the assisting force is obtained from this, the number of sensors does not increase.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

[Fig. 2] Power system diagram

[Fig. 3] Motor control system diagram

[Fig. 4] Operation flow chart

[Fig. 5] Operation explanatory diagram

FIG. 6 is a diagram showing a waveform of a voltage applied to a motor.

[Explanation of symbols]

 22 electric motor 32 crank pedal 54 controller 68 CPU 68A memory 68B auxiliary force calculation / correction means 68C electric power circuit

Claims (1)

[Claims] 1. A vehicle with an electric motor in which a human-powered drive system and an electric drive system are provided in parallel, and the assisting force by the electric drive system is controlled substantially in proportion to the driving force by the human-powered drive system. A rest period and an application period are alternately provided cyclically, and the manpower / result detection means for detecting the manpower driving force in the rest period and the resultant force of the manpower driving force and the assisting force in the application period, respectively, A memory for storing a target value of the assisting force corresponding to the detected human-powered driving force, and an actual value of the assisting force obtained by subtracting the human-powered driving force from the resultant force detected by the human-power / result-force detecting means An auxiliary force calculation / correction means for comparing the target value with the target value and correcting the target value, and a power circuit for controlling the auxiliary force so that the auxiliary force matches the corrected target value are provided. Vehicle with electric motor.