JPH01206807A - Driving force controller for motor vehicle - Google Patents

Abstract

PURPOSE:To enable suppression of slippage of right and left wheels at any timing, by obtaining a driving force correcting signal by calculation based on a slip ratio obtained from a vehicle speed signal and a rotation speed signal. CONSTITUTION:A slip detecting means 20 operates the slip ratio of driven wheels based on a vehicle speed signal fed from a vehicle speed sensor 11 and a rotation speed signal fed from a rotation speed sensor 12 and produces a driving force correction signal. A motor control amount operating means 30 operates a control amount signal based on a load signal fed from a load sensor 13, an accelerator angle signal fed from an accelerator angle sensor 14 and a driving force correction signal fed from a slip detecting means 20. Motor controllers 41, 42 for a driving means 40 regulate the electric power to be fed to motors 51, 52 for driving respective driven wheels 61, 62 based on the control amount signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a driving force control device for an electric vehicle.
More specifically, the present invention relates to a driving force control device for an electric vehicle in which a pair of left and right drive wheels are driven by separate motors.

[Conventional technology and its problems]

Generally, in order to maximize the driving performance of a vehicle,
In principle, it is necessary that the left and right driving forces be equal for both straight-ahead travel and turning travel. However, if either the left or right drive wheel enters an icy road, depression, mud, etc. and idles, the above principle of equal drive force on the left and right cannot be applied, and the control system '4B (1) weakens the drive force of the idle shaft. -Raction system '4B) is required.

Incidentally, an electric vehicle is known in which a pair of left and right drive wheels are driven by separate motors, with the main aim of eliminating the need for a steering wheel or an actuating device. This type of electric vehicle is suitable for traction control, and various control methods have been proposed for the purpose of the above control.

As this traction control method, there is a ``Electric Vehicle Control Method'' (Japanese Patent Application Laid-Open No. 60-32501) that prevents the drive wheels of an electric vehicle from spinning or skidding.

As shown in FIG. 2, in an electric vehicle in which the left and right drive wheels are driven by separate electric motors, this control system first starts by controlling the left and right drive motors 73L.
, 73R transfers the power from the battery 71 to the thyristor 72L.
, 73R. Next, the signals from the rotation detectors 74L, 74R of each motor 73L, 73R enter a low value priority circuit 75 and comparison circuits 76L, 76R. This results in (higher rotation speed - lower rotation speed)
The rotational speed difference signal ΔN of the idling torque regulator 77L,
Enter any of 77H. When this electric vehicle is not idling, the speed difference between the left and right wheels is a constant value N8 determined by the position of the wheels and the turning radius. Idle torque adjuster is ΔN
It is determined that idling has occurred when the torque exceeds N, and the torque signal commanded by the accelerator 80 is exceeded (ΔN-
N, ) and input it to the speed regulator 78L or 78R. Then, this signal is transmitted to the firing angle adjusters 79L, 7.
Thyristors 72L and 72R are controlled via 9R. Therefore, when the difference in rotational speed between the left and right drive wheels exceeds a predetermined value, the drive wheel with a higher rotational speed is weakened, so that slipping is suppressed.

However, with this conventional electric vehicle control method,
Since it is determined that idling is occurring when the difference in rotational speed between the left and right sides becomes larger than a predetermined value, simultaneous idling on the left and right sides cannot be detected. Also,
There is a problem in that it is impossible to deal with the situation when the rotational speed difference becomes smaller than a predetermined value, such as when the inner wheel idles during turning drive. Furthermore, in a typical electric vehicle, when turning, the same driving force command is given to the left and right wheels, so the inner wheel with the smaller slip limit driving force slips first, and from that point on, the commanded driving force of the inner wheel is weakened. Therefore, the combined driving force of both wheels cannot be maximized, and slip ratio control is entered early, which increases the frequency of turning on and off the driving force, resulting in a problem in that the drive feeling deteriorates.

Therefore, the present inventors conducted intensive research to solve the problems of the prior art as described above, and as a result of conducting various systematic experiments, they came up with the present invention.

[Purpose of the invention]

The purpose of the present invention is to be able to detect and suppress idling of the left and right wheels at any timing and under any circumstances, and to provide the maximum driving force to each of the inner and outer wheels during a turn. An object of the present invention is to provide a driving force control device for an electric vehicle that can easily turn even with a small turning radius.

The present inventors solved the main problem of the prior art described above by giving separate torque commands to the motors for the inner and outer wheels, taking into account changes in the vehicle load during turning. I focused on solving the problem.

[Description of the invention]

The driving force control device for an electric vehicle of the present invention is a device for controlling the driving force of an electric vehicle as shown in FIG. , a vehicle speed sensor 11 that detects the speed of the vehicle, a rotational speed sensor 12 that detects the rotational speed of the driving wheels of the vehicle, a load sensor 13 that detects the load on the driving wheels of the vehicle, and an opening degree of the accelerator. A slip ratio (idling ratio) of the drive wheels is calculated from the accelerator angle sensor 14, the vehicle speed signal output from the vehicle speed sensor 1, and the rotation speed signal output from the rotation speed sensor 12, and a driving force correction signal is output. a slip detection means 20 that
Necessary for correcting and controlling the driving force of the vehicle based on the driving force correction signal output from the slip detection means 20, the load signal output from the load sensor 13, and the accelerator angle signal output from the accelerator angle sensor 14. motor control amount calculation means 30 that calculates a control amount corresponding to the driving force and/or braking force according to the drive wheel load of the vehicle and outputs a control amount signal for each drive wheel; A first motor control device 41 and a second motor control device 42 that adjust electric power supplied to the motor based on a motor command signal as a control amount signal that is an output, and the first motor control device 41 and the second motor control device 42 and a power supply source 43 that supplies power to the motor; and a control force that matches the driving force according to the state of the drive wheels of the electric vehicle based on the electric power controlled by the drive means 40. a first motor 5 that continuously and variably controls the torque of each shaft of the driving wheels so as to generate a driving force and follow the driving force;
1 and a second motor 52.

The functions and effects of the present invention having the above configuration are as follows. That is, in the present invention, in a driving force control device for an electric vehicle in which the drive wheels of the vehicle are driven by separate electric motors, first, the vehicle speed is detected by the vehicle speed sensor 11, and the detected vehicle speed is converted into an electrical signal corresponding to the vehicle speed. Further, the rotational speed sensor 12 detects the rotational speed of the drive wheels of the vehicle and converts it into an electrical signal corresponding to the rotational speed. Also,
The load sensor 13 detects the load applied to the drive wheels of the vehicle and converts it into an electrical signal or the like corresponding to the load. Furthermore, the accelerator angle sensor 14 detects the opening degree of the accelerator and converts it into an electrical signal corresponding to the accelerator angle.

Then, based on the vehicle speed signal output from the vehicle speed sensor 1 and the rotation speed signal output from the rotation speed sensor 12, the slip detection means 20 calculates the slip ratio (idling ratio) of the drive wheels of the vehicle from the rotation speed signal. The driving force correction signal is calculated by dividing the difference between the circumferential speed of the driving wheel and the vehicle speed by the circumferential speed of the driving wheel, and outputs a driving force correction signal as a target value for correction control.

Then, in the motor control amount calculation means 30, based on the driving force correction signal outputted from the slip detection means 20, the load signal outputted from the load sensor 13, and the accelerator angle signal outputted from the accelerator angle sensor 14, The driving force and/or necessary to correct and control the vehicle's driving force.
Or a system that matches the braking power? lit, that is, the torque required for the first motor 51 and the second motor 52, and outputs a torque command signal according to the driving wheel load.

And this motor system? 11 Based on the motor command signal which is the output of the quantity calculation control means 30, in the drive means 40,
First motor control device 41 and second motor control device 42
The first motor 51 and the second motor 52 generate a control force according to the state of the drive wheels 61 and 62 of the electric vehicle to follow the drive force. The shaft torque of each of the drive wheels 61 and 62 is continuously and variably controlled so as to.

Note that the power supply source 43 of the driving means 40 is connected to the first motor control device 41 and the second motor control device 42 to supply power to the motor.

By doing as described above, the driving force control device for an electric vehicle of the present invention weakens the driving force of the left and right driving wheels individually based on the slip ratio calculated individually, so that Even if the vehicle idles under certain conditions, it can be detected and suppressed.

Furthermore, by detecting the load shift during turning and commanding a small drive force to the inner wheel with a low slip limit drive force and a large drive force to the outer wheel with a high slip limit drive force,
Since maximum driving force can be applied to each of the inner and outer wheels during a turn, the vehicle can turn at higher speeds on roads with a low coefficient of friction, and can also turn easily even with a small turning radius. In addition, when increasing the driving force, the inner wheels, which previously started slipping first, are delayed, so the frequency of anti-slip control is reduced, and the deterioration of drive feeling can be minimized. Can be done.

[Description of other inventions]

The basic concept of other inventions related to control methods that can be applied to the driving force control device of the present invention will be briefly explained by giving an example using FIGS. 3 and 4. First, 1) During straight running, the motor control amount calculating means 30 equally commands the left and right motors to apply a driving force [FIG. 4(a)] that is approximately proportional to the accelerator angle/brake angle. The driving force f is determined from the driving force coefficient μ and the vertical load W applied to the driving wheels using the following formula.

f = μ W (1) The driving force coefficient μ is determined by the friction coefficient of the road surface, the tire slip ratio, etc., and has a maximum value μm at a certain slip ratio. Therefore, the driving force also has a maximum value f, (=μ, W), and slipping occurs when the accelerator is depressed beyond the accelerator angle θ, which corresponds to fl. As a result, the slip detection means 20 outputs a corrected driving force signal. When this signal is generated, the motor control amount calculation means 30 calculation means weakens the driving force command value by that amount.

In other words, when the accelerator angle θ≦θ, with Kt as a proportionality constant, f L' = f +t'' = Kt θ
... (2) Kt is the maximum driving force on a high-friction road surface (+1 and maximum accelerator angle θ° 1, KL ``' f '' -/ θ°, ...
(3) is set in advance.

When θ, θ, the driving force command f♂ is equal to the corrected driving force.
, fm''' is weakened.

As a result, when the slip stops, the driving force command increases to the value determined by equation (2). Although it is difficult to know r itself, by repeating the above increase/decrease, the result is f♂=fll$ζf, (4).

2) The driving force coefficient changes in response to large changes in load during cornering. However, within the range of load changes where the influence on the driving force coefficient can be ignored, the limit driving force f1 changes the driving wheel load to W, ,
W, then the limit driving force of the inner and outer wheels is fi, fO+e is as follows.

fis-μW! ... (5)f
o, = μW0 (6) That is, the limit driving force becomes larger for the outer ring and smaller for the inner ring due to load movement. In response, the left and right motor control amount calculation means 30 calculate the accelerator angle θ as shown in FIG. 4(b).
, fLO" = KtO1θ, ... (7) fti"
= Kti・θ,
・ ・ ・ 6Kto, Kti that outputs the torque command such as (8) are (1), (2), (5),
From (6), it can be obtained as follows.

Kt, = (we/W)KL... (9)K
ti = (Wt / W)K, ... 0
0) W is the left and right wheel load when traveling straight, Wζ(W.

+Wi)/2.

Next, the torque command rto for the inner and outer rings. , f ti are converted into left and right wheel torque commands f tL'', full''.

Now, assuming that the outer ring = left wheel, w0 = = wL, W! =W, W=(W, +W++)/2
f♂=ftO"=Iris iK, ・θ, =-Kujiichi Island・θ, ... (II) WL+W, I r t, I""" r tl" =-Ran K, ・θ, =
-”y knee K,,・θ, ... 02) WL +w
R Here, WL WR=2ΔW ・ ・ ・ 03
)Wt+W*=2W ・ ・ ・ 0
4), equations 01) and 02) become as follows.

In the above, it is assumed that the left wheel is the outer wheel for turning, but even if the right wheel is the outer wheel, the sign of ΔW on the side is reversed, so the above conversion formula holds true as is.

Therefore, if the wheel loads WL, W are known, the command torque during driving can be determined from equations (13) to 0ω.

The wheel load is measured by a load sensor 1 built into the suspension spring of the drive wheel.
Measured by 3L and 13R.

Even when turning, the command torque is determined by the signal from the slip detection means 20 to reach the limit driving force f at a certain accelerator angle or more, similar to when going straight. , , is saturated corresponding to fin [Fig. 4(b)].

Next, the slip detection means 20 inputs signals from the vehicle speed sensor 11 and the left and right drive wheel rotational speed sensors 12L and 12R, and outputs a slip signal to the motor control amount calculation means as described below.

λ is the slip ratio, and is selected to be λ=0.2 to 0.3.

Next, in the motor control system of the driving means 30, the torque command f
L'', fllI is a normal PWM (
The electric power supplied from the power supply source 43 to the first motor 51 and the second motor 52 is controlled by pulse width control), and the vehicle runs while following the commanded driving forces f♂ and fR'.

By doing so, the slips of the left and right wheels during driving are detected separately, and the optimum torque command is given to each drive motor. As a result, if both wheels slip or lock at the same time, or if the inner wheel slips and the outer wheel locks so that the difference in rotational speed between the two wheels becomes small during a turn, the system will respond to the accelerator signal. It is possible to perform liver pump prevention.

Furthermore, conventionally, as shown in FIG. 4(c), since the same command value is issued for both the inner and outer wheels, the commanded driving force f for the outer wheel. ' is the slip limit accelerator angle θ when traveling straight, and the limit driving force f is greater than θ1''. , and the commanded driving force fi* of the inner wheel reaches the limit driving force r1 at an accelerator angle θ,゛ smaller than θ1.

Therefore, the total driving force f. I0ft is when the accelerator angle θ is θ1
≦θ≦θ,'', the driving force is smaller than the one that can normally be generated.On the other hand, in this control method, when turning, the commanded driving force is set so that the inner wheel becomes smaller and the outer wheel becomes larger according to the movement of the wheel load. In other words, as illustrated in Fig. 4(b), f0' becomes fOm near the accelerator angle θ1,
Since f, 11 is controlled so as to reach f i+m, the total driving force can be increased to near the slip limit. This allows it to turn faster than before on icy roads with a low coefficient of friction. In addition, the accelerator angle at which anti-slip control starts increases from θ1" to θ, so anti-slip control is performed less frequently. Normal anti-slip control involves increases and decreases in motor torque, so Although it is inevitable that the feeling will deteriorate to some extent,
Reducing the frequency of anti-slip control has the effect of minimizing this deterioration in drive feeling. Furthermore, as an additional effect, a moment that promotes turning acts on the vehicle body due to the difference in driving force between the inner and outer wheels, making it easier to turn in a particularly small radius.

〔Example〕

A driving force control device for an electric vehicle according to a first embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 5, the driving force control device for an electric vehicle of this embodiment includes a vehicle speed sensor 11, rotational speed sensors 12L, 1
2R, load sensors 13L and 13R, accelerator angle sensor 14, slip detection means 20, motor control amount calculation means 3o, drive means 40, first motor 51, and second motor 52. .

The vehicle speed sensor 11 detects the speed of the vehicle, is composed of a tacho generator, and is incorporated into a transmission (not shown).

The rotational speed sensors 12L and 12R detect the rotational speed of the drive wheels of the vehicle, and include an encoder 121.122 built into the motor shaft and a signal processing circuit 123.122 that integrates the output pulses and converts them into analog values. It consists of 124.

The load sensors 13L and 13R detect the load applied to the drive wheels of the vehicle, and are composed of load cells built into suspension springs of the drive wheels.

The accelerator angle sensor 14 detects the opening degree of the accelerator, and is composed of a potentiometer built into the engine carburetor.

The slip detection means 20 consists of an amplifier 211.212, a subtracter 221.222, a divider 231.232 and a comparator 241.242.

The amplifiers 211 and 212 are connected to the rotational speed sensors 12L and 12.
R, and amplify the rotation speed signals ω1 and ω of the left and right wheels output from the sensor by r times (wheel radius times), respectively.
The amplified signal is output.

Subtractors 221 and 222 are connected to amplifiers 211 and 212, respectively, and subtract the vehicle speed signal V output from the vehicle speed sensor 11 from the amplified signal output from the amplifiers.

Dividers 231 and 232 are connected to subtracters 221 and 222 and amplifiers 211 and 212, respectively, and
．． 222 and the amplifier 211.
The amplified signal output from 212 is divided by the slip ratio λ
, L, λ, and R are calculated.

r ωL r ωL Comparators 241.242 are divided by dividers 231.232
When the signals λ, L, λ, output from the dividers 231 and 232 exceed λ (0.2 to 0°3), fsL and f□ (both are less than the maximum driving force of each wheel). A small arbitrary positive number (for example, 50 kg) is output as the corrected driving force signal, and when the value does not exceed the value, 0 is output as the corrected driving force signal.

The control amount calculation means 30 includes an adder 311.312, a subtracter 321.322.323.324, a multiplier 331, a divider 341, and an amplifier 351.352.353.

Adder 311 is connected to load sensors 13L and 13R, and adds wheel load signals WL and WR output from the sensors.

The subtracter 321 is connected to the load sensors 13L and 13R, and subtracts WR from the wheel load signal WL output from the sensors.

The amplifier 351 is connected to the adder 311 and the adder 31
The signal output from 1 is multiplied by 1/2 and the signal W is output (corresponding to equation 04 above). Further, the amplifier 352 is
It is connected to a subtracter 321, and the signal output from the subtracter 321 is multiplied by 1/2 to output a signal ΔW (corresponding to the above equation 0).

Divider 341 is connected to amplifiers 351 and 352,
The signal ΔW output from the amplifier 352 is sent to the amplifier 351.
The signal ΔW/W is calculated by dividing by the signal W output from the ΔW/W.

The amplifier 353 is connected to the accelerator angle sensor 14, and multiplies the signal θ output from the sensor by Kt to obtain a signal Kt.
Output θ1.

The multiplier 331 is connected to the amplifier 353 and the divider 341, multiplies the signal output from the amplifier 353 by the signal output from the divider 341, and gives the signal ・θ1 ・ΔW/W
Output.

The adder 312 is connected to the amplifier 353 and the multiplier 331, and adds 1·θ to the signal output from the amplifier 353 and Kt·θ,·ΔW/to the signal output from the multiplier 331.
W and outputs f□' (corresponding to equation 05 above).

The subtracter 322 is connected to the amplifier 353 and the multiplier 331, and receives the signal Kt·θ, which is output from the amplifier 353.
and the signal Kt output from the multiplier 331 ・θ, ・ΔW
/W and outputs f tR'' (corresponding to formula 06 above).

The subtracter 323 is connected to the adder 312 and the comparator 241 of the slip detection means 20, and subtracts the signal f!L output from the comparator 241 from the signal ftL" output from the adder 312, and outputs f♂.

The subtracter 324 is connected to the adder 322 and the comparator 242 of the slip detection means 20, subtracts the signal f3N output from the comparator 241 from the signal r t*'' output from the adder 312, and outputs fR*.

The driving means 40 includes a first motor control device (left) 41 and a second motor control device (right) 42 that are composed of a PWM type chopper, a power supply source 43, and a triangular wave generation circuit that outputs a high-frequency modulation signal. It consists of 44.

The first motor control device 41 includes the motor control amount calculation means 30
a subtracter 411 connected to the subtracter 323 and the triangular wave generation circuit 44 and subtracting the modulation signal output from the circuit 44 from the signal f- output from the subtracter 323;
11 and a drive circuit (not shown), and the subtracter 4
When the signal output from 11 is positive, the high level signal is
A zero cross comparator 412 that outputs a low level signal when negative is connected to the zero cross comparator 412 via a drive circuit BL, and is repeatedly turned on and off according to the signal of the drive circuit BL, thereby controlling the supply voltage of the first motor 51. and a power transistor switch 413 that adjusts the average power.

The second motor control device 42 includes the motor control amount calculation means 30
A subtracter 421 is connected to the subtracter 324 and the triangular wave generating circuit 44, and subtracts the modulation signal output from the circuit 44 from the signal rlI$ output from the subtracter 324, and the subtracter 421 and the drive circuit (Fig. (not shown) and outputs a high level signal when the signal output from the subtracter 421 is positive, and outputs a low level signal when the signal output from the subtracter 421 is negative; and the zero cross comparator 422 and drive circuits B and I. and the drive circuit B
The power transistor switch 423 is configured to mflff the average power supplied to the second motor 52 by repeatedly turning on and off according to the +t signal.

The power supply source 43 is connected to the first motor control device 41 and the second motor control device 42, and is connected to the transistor section 413.4.
23 in series to supply power to the motors 51, 52.

The first motor 51 is connected to the left drive wheel (not shown) and continuously variably controls the torque of each shaft of the drive wheel based on the electric power controlled by the drive means 40.

The second motor 52 is connected to the right drive wheel (not shown) and continuously variably controls the torque of each shaft of the drive wheel based on the electric power controlled by the drive means 40.

The functions and effects of this embodiment having the above configuration are as follows.

■) When traveling straight When traveling straight, there is no load shift due to rolling of the vehicle body, so ΔWζO. Therefore, the outputs of the divider 341 and the multiplier 331 are zero, and the outputs of the adder 312 and the subtracter 322 are ftt,"=fti"=
Kt ・θ.

If the outputs of the slip detection means 20 are all zero, K1 ・θ is the motor torque command value f♂, flI
It is output to the driving means 40 as $.

In the driving means 40, a power transistor switch 413
．． 423, a voltage approximately proportional to f♂, fjI* is applied to the first motor 51 and the second motor 5.
2, the vehicle runs with equal driving or braking force on the left and right sides proportional to the accelerator angle θ.

When these driving forces exceed a limit value determined by the coefficient of friction between the road surface and the tires, slipping occurs. At this time, the slip ratio λ is calculated from the vehicle speed and the rotational speed of the wheels for each of the left and right wheels using a subtractor 221.222 and a divider 231.232, and is compared with the limit slip ratio λ at a comparator 241.242. When λ, >λ, it is determined that there is a slip, and the comparators 241 and 242 output a corrected driving force fsLsL* for slip control. This corrected driving force is converted into command values f, ♂, f tR by subtracters 323 and 324.
''', so the motor's driving force weakens and the slip stops.When the slip disappears, the 5 driving force is ft.
, f tll''. By repeating this process, the average driving force is maintained close to the limit value. In this way, the characteristics shown in Fig. 4(a) are achieved. However, if it is not desirable to perform slip correction too frequently, the comparator 241.
242 may have some hysteresis characteristics.

2) When the vehicle is turning When the vehicle is turning, the rolling of the vehicle body causes a load transfer ΔW from the inner wheel to the outer wheel. When the outer ring is the left wheel, ΔW〉
It is 0. The load change rate ΔW/W is calculated by the adder 311, the subtracter 321, the amplifiers 351 and 352, and the divider 341. Furthermore, the multiplier 331, the adder 312, and the subtracter 322 execute calculations corresponding to equations 05) and 06), and output the command values f5♂, r t*. , the outer ring (ft♂) is commanded to be larger by an amount proportional to ΔW, and the inner ring (ft, ") is commanded to be smaller. When a slip occurs, the same control as when traveling straight is performed, so that the characteristics shown in FIG. 4(b) can be achieved.

As a result, the vehicle equipped with this embodiment device separately detects the slip of the left and right wheels during driving and provides the optimum torque command to each drive motor, so that if both wheels slip or lock at the same time, When the inner wheel slips and the outer wheel locks, such as when the rotational speed difference between the two wheels becomes small during a turn, slip prevention can be performed in response to an accelerator signal.

Furthermore, the device of this embodiment controls the commanded driving force to be small for the inner wheel and large for the outer wheel according to the movement of the wheel load during cornering, that is, as illustrated in FIG. 4(b),
f near the accelerator angle θ. ' is fOm, fig is f
ig, the total driving force can be increased to near the slip limit. This results in
It can turn faster than before on icy roads with a low coefficient of friction. Also, the accelerator angle at which the anti-slip control starts is θ, “
→ Since it increases to θ0, the frequency at which the anti-slip control is performed decreases. As a result, since normal slip prevention control involves an increase or decrease in motor torque, it is inevitable that the drive feeling will deteriorate to some extent, but in the case of this embodiment, it is effective to minimize the deterioration of the drive feeling. be. Furthermore, as an additional effect, a moment that promotes turning acts on the vehicle body due to the difference in driving force between the inner and outer wheels, making it easier to turn in a particularly small radius.

Second Embodiment A driving force control device for an electric vehicle according to a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, in the driving force control device for an electric vehicle according to the first embodiment, the steering angle signal obtained from the steering angle sensor 15 is further inputted to the motor control amount calculation means 30, and the steering angle signal is also taken into account. This is to obtain an appropriate motor control amount.

Hereinafter, the differences from the first embodiment will be explained in detail.

First, the steering angle sensor 15 is composed of a potentiometer, and is mounted coaxially with the steering wheel in order to measure the steering angle of the steering wheel.

Next, the control amount calculation means 30 includes adders 311, 312, subtracters 321, 322, multiplier 331, and divider 3.
41 and amplifiers 351, 352, and 353, it further includes an absolute value circuit 361, a comparator 362, and an input signal changeover switch 363.

The steering angle signal δ output from the steering angle sensor 15 is input to a control terminal of an input signal changeover switch 363 via an absolute value circuit 361 and a comparator 362. The input signal changeover switch 363 inputs the output of the divider 341 to one terminal H, and grounds the other terminal. When a high level signal is input to the control terminal of the input signal changeover switch 363, the input signal is switched to the H input, and when a low level signal is input, the input signal is switched to the L input.

From this, when traveling straight, the output of the comparator 362 becomes low level because δ and -0, and the input of the input signal changeover switch 363 is on the L side, so the load movement amount Δ
The signal corresponding to W is ignored. Therefore, in this case,
The driving force command f♂ is determined only by the accelerator angle θ.

Further, during turning, since δ3≠0, the input signal changeover switch 3630 input is on the H side, and the same control as in the first embodiment is executed.

By doing so, the driving force control device for an electric vehicle according to the present embodiment not only has the effects of the driving force control device for an electric vehicle according to the first embodiment, but also has the following effects.

That is, in such an electric vehicle, there may already be a difference in the load on the left and right wheels when the vehicle is traveling straight, depending on the position of the occupant, the load, etc. In such a case, the first
In the control device of the embodiment, since there is a difference in driving force between the left and right sides, appropriate driving force control cannot be performed, which is not preferable. On the other hand, in this embodiment, the load response control is performed only when turning when there is a difference in the left and right wheel loads, so the problem when driving straight as described above does not occur, and appropriate driving force control is performed. It becomes possible.

Third embodiment The arrangement will be explained using FIG.

In the present embodiment, in the driving force control device for an electric vehicle according to the first embodiment, the vehicle speed signal obtained from the vehicle speed sensor 11 is further inputted to the motor control amount calculation means 30, and the vehicle speed signal is also taken into account to determine the appropriate value. This is to obtain the motor control amount.

Hereinafter, the differences from the first embodiment will be explained in detail.

The control amount calculation means 30 of this embodiment includes adders 311 and 31.
2, subtracters 321, 322, multiplier 331, divider 341, and amplifiers 351, 352, and 353, in addition to saturation amplifier 354, multiplier 332, and subtracter 32.
5.

The saturation amplifier 354 is connected to the vehicle speed sensor 11, and based on the vehicle speed signal V output from the vehicle speed sensor 11, V≦v
In the case of c, v/vc is output, and in the case of v>vc, 1 is output. Here, ■. is the limit vehicle speed, and 401aII/
Set an appropriate value between h and 1001aIl/h.

Next, the multiplier 332 is connected to the saturation amplifier 354 and the divider 341, and adds the signal (ΔW/W) output from the divider 341 to the signal output from the saturation amplifier 354.
and outputs the signal to the subtracter 325.

Next, the subtracter 325 includes a multiplier 332 and a divider 34
1, subtracts the signal output from the divider 341 from the signal output from the multiplier 332, and outputs the signal to the multiplier 331. Therefore, the output of the subtractor 325 is as follows.

From this, the multiplier 331 has 07 instead of ΔW/W.
) The calculation result shown in the formula is input. Therefore, ftt”
, ft, " (7) The degree of dependence on load shift ΔW/W becomes weaker as ■ becomes larger. Also, when ■ exceeds a certain value vc, the load shift bone is ignored and the same driving force is applied to the left and right wheels. commanded.

By doing so, the driving force control device for an electric vehicle according to the present embodiment not only has the effects of the driving force control device for an electric vehicle according to the first embodiment, but also has the following effects.

That is, in the first embodiment, when the vehicle is turning, a moment that promotes the turning is generated due to the difference in driving force between the inner and outer wheels. Although this effect works effectively when driving at low speeds, there is a problem in that at high speeds, there is a risk that stability may be impaired in the case of vehicles with sensitive steering characteristics. On the other hand, in this embodiment, the difference in driving force between the inner and outer wheels is reduced as the speed increases, so it is stable at high speeds and does not cause the above-mentioned problems when driving at high speeds. Appropriate driving force control becomes possible.

Fourth Embodiment A driving force control device for an electric vehicle according to a fourth embodiment of the present invention will be described with reference to FIG.

In this embodiment, in the driving force control device for an electric vehicle according to the first embodiment, a motor control amount calculation means 30 and a drive means 40
Between the input signal changeover switches 81 and 82 and the subtractor 83.
84, and a divider 233.84 is provided in the slip detection means.
234 and comparators 243 and 244, and the motor control amount calculation means 30 is further provided with an amplifier 355 for amplifying the signal output from the brake angle sensor 16.

Hereinafter, the differences from the first embodiment will be explained in detail.

First, the brake angle sensor 16 is a potentiometer attached to the brake pedal to measure the brake angle and output a brake angle signal θ.

Next, the slip detection means 20 includes amplifiers 211 and 212.
In addition to the subtracters 221 and 222, the dividers 231 and 232, and the comparators 241 and 242, there is also a divider 23.
3.234 and comparators 243.244.

The divider 233 is connected to the vehicle speed sensor 11 and the subtracter 22, divides the signal output from the subtracter 221 by the vehicle speed signal 2 output from the vehicle speed sensor 11, and outputs a signal λLL to the comparator 243. do.

The divider 234 is connected to the vehicle speed sensor 11 and the subtracter 222, divides the signal output from the subtracter 222 by the vehicle speed signal V output from the vehicle speed sensor 11, and outputs a signal λ to the comparator 244. do.

The dividers 233 and 234 calculate the lock (restraint) ratio of the left and right wheels as follows.

Comparators 243 and 244 are divided by divider 2, respectively.
33 and 234 and are connected to subtractors 83 and 84,
When the input signals λ, L, λ exceed one λ (λ = 0.2 to 0.3), it is 0, and when it does not, it is ALL, λ1ll (
(both of which are arbitrary positive numbers smaller than the maximum control force for each wheel) are output as auxiliary braking force.

Next, the control amount calculation means 30 includes an adder 311.312, a subtracter 321.322.323.324, and a multiplier 3.
31, divider 341, and amplifier 351.352.35
3, it further includes an amplifier 355 for amplifying the signal output from the brake angle sensor 16.

The amplifier 355 inputs the brake angle signal θ output from the brake angle sensor 16 and amplifies it by a factor of 1, f b
"" Outputs a signal of K b ·θゎ.

Next, input signal changeover switches 81 and 82 and a subtractor 83 are provided between the motor control amount calculation means 30 and the drive means 40.
and 84 are provided.

Subtractors 83 and 84 are connected to the b-side terminals of amplifier 355 and input signal changeover switches 81 and 82, respectively, and input a signal obtained by subtracting the corrected braking force from fb* to these terminals.

The input signal changeover switches 81 and 82 have subtracters 323 and 324 at the terminals on the a side, and subtractor 83 at the terminals on the b side.
and 84 are further connected to the brake angle sensor 16 through control terminals, and when the brake angle signal θ, = 0, the input terminal of the switch is switched to the t side, and when θ, > 0, the input terminal of the switch is switched to the b side. and subtractors 411 and 421, respectively.
is output to.

As a result, when θ=0, that is, when the brake is not depressed, the inputs of the input signal changeover switches 81 and 82 are connected to the t terminals, so that the same operation as in the first embodiment is performed. Further, when θb>0, that is, when the brake is depressed, the input signal changeover switch 81
．． The input of 82 is connected to the b-side terminal. Further, when the corrected braking force which is the output of the slip detection means 20 is zero,
The brake angle θ, is multiplied by the amplifier 355 to K
b - The signal of θ1 is sent to the motor braking torque command f via the subtractor 83.84 and the input signal changeover switch 81.82.
It is output to the driving means 4° as L", fll".

Also, when the lock ratios λ, L, and λ calculated from the vehicle speed and the rotation speed of the left and right wheels using the formula 00 do not exceed 1λ (λL
L+λ, ≦−λ), it is determined that the brake wheels are locked. At this time, the comparators 243 and 244 output the corrected braking force command value fLLsfLR.

Then, in the subtracters 83 and 84, fLLsfLR is subtracted from the original braking force command value Kb·θ, so that
The motor braking force command is made weaker than when no lock occurs. Therefore, the braking force of the brake wheels is weakened,
The lock is released and the wheels regain their adhesion to the road. From this, the braking force command value also returns to .theta..

Thereafter, the above process is repeated.

By doing so, the driving force control device for an electric vehicle according to the present embodiment not only has the effects of the driving force control device for an electric vehicle according to the first embodiment, but also has the following effects.

That is, during driving, the same effects as in the first embodiment are achieved. It also has the function of operating the drive motor as a generator during braking and using it as a regenerative brake.

The braking force of the motor is controlled to maintain a value close to the maximum value within the range where the wheels do not lock, so the vehicle can be reliably stopped without losing its direction even on low-friction, icy roads. .

In the above-mentioned embodiment, the drive source of the vehicle is composed of a pair of left and right motors, but it is not limited to this. For example, it may be equipped with one or more pairs of motors, or a hybrid power source equipped with an internal combustion engine may be used. It may be a vehicle.

Further, the turning does not have to be based only on a normal steering device, and a pair of left and right steering motors may be provided in addition to the drive motor of the above-described embodiment.

Furthermore, the driving force control device for an electric vehicle according to the above-mentioned embodiments has the following features:
It is especially suitable for recreational electric vehicles that drive on a variety of roads such as highways, mountain roads, and icy roads.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram showing the concept of the present invention, Fig. 2 is a schematic block diagram of the prior art, Figs. 3 and 4 show other inventions, and Fig. 3 is a schematic block diagram showing the concept. , FIG. 4 is a diagram showing the principle, FIG. 5 is a system configuration diagram showing the entire first embodiment, FIG. 6 is a partial system configuration diagram showing the second embodiment, and FIG. 7 is a diagram showing the third embodiment. Partial system configuration diagram showing an example,
FIG. 8 is a system configuration diagram showing the entirety of the fourth embodiment. 11...Vehicle speed sensor, 12...Rotation speed sensor, 1
3... Load sensor, 14... Accelerator angle sensor, 2
0... Slip detection means, 30... Motor control amount calculation means, 40... Drive means, 41... First motor control means, 42... Second motor control means, 43... Electric power Supply source, 51...first motor, 52...second motor, 61.62...drive shaft.

Claims (1)

[Claims] (1) A driving force control device for an electric vehicle in which the drive wheels of the vehicle are driven by separate electric motors, which includes a vehicle speed sensor that detects the speed of the vehicle, a rotation speed sensor that detects the rotation speed of the drive wheels of the vehicle, and a vehicle. a load sensor that detects the load applied to the drive wheels; an accelerator angle sensor that detects the opening degree of the accelerator; and a drive wheel based on the vehicle speed signal output from the vehicle speed sensor and the rotation speed signal output from the rotation speed sensor. a slip detection means for calculating a slip ratio (idling ratio) of and outputting a driving force correction signal; a driving force correction signal outputted from the slip detection means; a load signal outputted from the load sensor; Based on the output accelerator angle signal, a control amount corresponding to the driving force and/or braking force necessary to correct and control the vehicle's driving force is calculated according to the vehicle's driving wheel load, and the control amount for each driving wheel is calculated. A motor control amount calculation means that outputs a signal, and a first motor control device and a second motor control that adjust electric power supplied to the motor based on a motor command signal as a control amount signal that is an output of the motor control amount calculation means. a drive means comprising a power supply source connected to the first motor control device and the second motor control device to supply power to the motor; and drive wheels of an electric vehicle based on the power controlled by the drive means. a first motor and a second motor that generate a control force commensurate with the driving force according to the state of the motor and continuously variable control the torque of each shaft of the drive wheel so as to follow the driving force; A driving force control device for an electric vehicle characterized by: