JPH11103507A - Speed controller for car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed controller for cars having a mechanism for compensating disturbances such as a running resistance, and capable of adjusting the speed of a car to a target speed with a high precision. SOLUTION: This controller controls the speed of a car 1 to a target speed by adjusting the torque of a running motor 7, and has a car speed detector 13, and a differentiating element 21 for computing the acceleration of the car. A disturbance estimating unit 23 estimates a disturbance such as the running resistance of the car, etc., from the torque of the running motor 7 and the acceleration of the car. Then a disturbance compensating unit 25 compensates the disturbance reflecting it in the torque of the motor 7. Namely, speed control in accordance with a speed deviation is preformed, after adding the estimated running resistance and the inertia force component of a load to the torque of a main motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device for controlling a speed of a vehicle driven by an electric motor such as an electric train on a railway to a target speed. In particular, the present invention relates to a vehicle speed control device having a mechanism for compensating disturbances such as running resistance and improving the vehicle speed to a target speed with high accuracy.

[0002]

2. Description of the Related Art The prior art will be described with reference to an electric railway car. In recent years, an increasing number of railway vehicles have a constant-speed traveling device that automatically adjusts the vehicle speed to a certain target speed. FIG. 5 is a diagram illustrating the operation principle of constant speed control during powering of a conventional electric vehicle. The horizontal axis represents the speed deviation ΔV, which is the difference between the target speed V _b ^* of the vehicle and the current speed V _b of the vehicle.
It is. The vertical axis is the output torque of the traveling motor. In the figure, the upper right diagonal line (torque pattern) 4
1 is shown. The torque pattern 41 shows the relationship between the current speed deviation [Delta] V, the moving electric motor torque T _m to be output accordingly. The upper right area in the drawing is an area where the current speed _Vb is smaller than the target speed _Vb ^* (the speed deviation is positive). In this region, except for a dead zone near the origin, control is performed such that as the speed deviation increases, the running motor torque increases substantially in proportion to the speed deviation. On the other hand, the lower left area is an area where the current speed _Vb is larger than the target speed _Vb ^* (the speed deviation is negative). In this region, the motor receives a braking torque proportional to the absolute value of the negative speed deviation as the absolute value of the negative speed deviation increases (excluding the dead zone near the origin) (the motor becomes a generator to apply a brake). Controlling. In addition,
A state where the output torque of the traveling motor is positive is called power running, and a state where the output torque is negative (braking) is called regeneration. This control, the range of speed deviation is expecting to fall within [Delta] V _ref from - [Delta] V _ref. The dead zone is provided in order to prevent the power deviation and the regenerative braking from being repeated when the speed deviation ΔV is around 0, thereby preventing the ride comfort from being deteriorated.

[0003] In the figure, a line 43a shown in parallel with the horizontal axis is shown.
And 43b indicate the torque corresponding to the running resistance of the vehicle. For example, when the value of the torque 43a corresponding to the running resistance is _Rt1
At this time, the balance is made at the point A where the line 43a and the line 41 of the torque pattern intersect, and the speed deviation ΔV becomes ΔV _bal1 . There is no problem if ΔV _bal1 falls within the target range. However, when the running resistance torque increases as indicated by 43b due to changes in track conditions, speed, and the like, the balance point moves from point A to point B. As a result, the speed deviation becomes ΔV _bal2 and exceeds ΔV _ref which is the upper limit of the target range of the speed deviation, and the vehicle speed _Vb greatly deviates from the target speed _Vb ^* .

[0004] Next, a description will be given of a deceleration brake control for performing speed control while applying a brake on a downward slope. FIG.
FIG. 5 is a diagram for explaining the operation principle of the conventional constant speed control during the deceleration braking of the electric vehicle. As shown in FIG.
In response to the value R _t3 of the running resistance torque 47a at a specific gradient (for example, 2.5%), the speed deviation becomes zero just according to the deceleration brake pattern 45 in which the speed deviation becomes zero. Is controlled so that However, like the slope of the gradient may change from a specific value of the, or the vehicle speed changes, if the value changes in the travel resistance torque 47b becomes R _t4, the speed deviation [Delta] V is [Delta] V _Bal4 becomes However, there is a problem in that a speed deviation occurs.

[0005] As one method for solving such a problem,
Focusing on the fact that the change in running resistance with respect to the speed of the vehicle is unique to the vehicle, there is a method of adjusting the torque pattern by detecting the vehicle speed _Vb . FIG. 7 is a diagram illustrating the operating principle of constant speed control when correcting the torque pattern according to the vehicle speed. In the case of constant speed control during power running, as shown in FIG. 7, the constant speed control torque is changed from the pattern 51a to the pattern 51b having a high output torque as the vehicle speed increases. As a result, even if the running resistance torque increases from 53a to 53b, control can be performed such that the speed deviation remains at ΔV _bal1 .

Next, a description will be given of the case of the speed-reducing brake control. FIG. 8 is a diagram for explaining the operating principle of constant speed control at the time of deceleration braking when the torque pattern is corrected according to the vehicle speed. As shown in FIG. 8, the deceleration braking pattern is changed from 55a to 55b as the vehicle speed increases. As a result, the running resistance torque is reduced from 57a to 5
Even if the speed falls to 7b, control can be performed so that the speed deviation remains at 0.

[0007]

However, since the running resistance changes not only with the speed but also with the line conditions such as the slope and the curve, it is impossible to completely cope with the above method. It is also conceivable to predict in advance or directly measure the running resistance due to the slope or curve on the vehicle side. However, for that purpose, a work for storing the track information in the control device on the vehicle in advance and a means for detecting a point are required, and further, it is effective only in the line section storing the track information, and economically. And not technically advisable.

The present invention has been made in view of the above problems, and is directed to a vehicle speed control device for controlling the speed of a vehicle driven by an electric motor such as an electric vehicle of a railway to a target speed. It is an object of the present invention to provide a vehicle speed control device that has a mechanism for compensating disturbance such as resistance and that can accurately adjust a vehicle speed to a target speed.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a vehicle speed control device of the present invention controls a vehicle speed to adjust to a target speed by adjusting a torque of a driving motor. A vehicle speed detector; means for detecting or calculating vehicle acceleration;
Means for detecting or estimating the torque of the traveling motor,
It is characterized by comprising: means for estimating a disturbance such as running resistance of the vehicle from the acceleration of the vehicle and the torque of the driving motor; and means for compensating the disturbance by reflecting the disturbance in the motor torque.

[0010] The running motor torque for balancing the speed varies depending on the change in the running resistance received by the vehicle. Therefore, in order to keep the vehicle speed at the target speed, the constant speed control torque pattern and the deceleration brake pattern must be adapted not only to the vehicle speed but also to the running resistance torque that changes depending on the line conditions and also the vehicle load conditions. And change it. For that purpose, it is sufficient that all running resistances of the vehicle can be estimated. For example, the generated torque of the main motor can be estimated from the current flowing through the main motor and the main motor constant.
Further, a vehicle inertia force corresponding to an empty vehicle can be estimated from the vehicle acceleration and the vehicle mass obtained by differentiating the detected vehicle speed. Then, by taking the difference between the torque generated and the vehicle inertia force converted from the generated torque, it is possible to estimate the sum of the running resistance received by the vehicle and the inertia force of the load.
By adding the inertia force of the running resistance and the load estimated by the above means to the torque of the main motor, and performing speed control according to the speed deviation, the running resistance and the load are not affected by changes in the running resistance and load. It is possible to make the vehicle speed close to the target speed by the speed deviation of -the main motor torque pattern.

[0011]

In the present invention, it is preferable that a change in inertial force caused by a change in the mass of the vehicle is compensated for as a disturbance. The true running resistance can be known by detecting the change in the mass of the vehicle by another means. However, even if such a change is made, even if the change in the inertial force due to the change in the mass of the vehicle is regarded as a disturbance and corrected collectively, the control accuracy does not have a serious adverse effect. By doing so, the control device and the program can be simplified.

In the vehicle speed control device of the present invention, a pulse generator, a tachogenerator, a resolver or the like can be used as the vehicle speed detector. The vehicle acceleration can be obtained by differentiating the vehicle speed, but may be detected using a separate sensor. The torque of the traveling motor may be calculated from the current value, or may be directly measured by a sensor such as a strain gauge. The means for estimating and compensating disturbance can be specifically configured as a program in a microcomputer.

Hereinafter, description will be made with reference to the drawings. FIG.
1 is a diagram schematically illustrating an overall configuration of an electric vehicle having a vehicle speed control device according to one embodiment of the present invention. Vehicle 1
It has four wheels 11a to 11d driven by four traveling motors 7a to 7d. A speed reducer 9 is interposed between the electric motor 7 and the wheels 11. Each traveling motor 7 is
Normal induction motor, permanent magnet synchronous motor, and its current? Is supplied and controlled by the traveling motor control device 5. Traveling motor control unit 5 receives a current command value i _q ^* from the vehicle speed control device 3.

Each wheel 11 is provided with a pulse generator 13 (only a wheel 11d is shown) as a vehicle speed detector, and sends a signal corresponding to the rotation speed of each wheel 11 to the vehicle speed control device 3. When the wheel 11 slips, the peripheral speed of the wheel and the vehicle speed are different. Therefore, usually, the peripheral speed of the slowest wheel is used as the vehicle speed during power running, and the peripheral speed of the fastest wheel is used during braking. The vehicle speed.

The vehicle speed control device 3 includes a differentiator 21, a disturbance estimator 23, a disturbance compensator 25, and the like.
The signal _Vbdet relating to the vehicle speed from the above-described wheels is input to the differentiating unit 21, which differentiates the signal _Vbdet and outputs the acceleration S of the vehicle. The disturbance estimating unit 23 receives the vehicle acceleration S from the differentiating unit 21 and the current command value _iq ^* to each motor, which is the output of the vehicle speed control device 3, and estimates a disturbance such as running resistance, and a disturbance compensating unit. 25. The disturbance compensator 25 includes:
Is the target speed from the speed command or the like which is placed in the driver's seat V _b ^* and the disturbance estimated value R _test from the disturbance estimation section 23 is input, outputs a new current command value i _q ^* with respect to the moving electric motor control unit 5 I do.

In FIG. 1, the equation of motion relating to vehicle running is described as follows. _{F = MdV b / dt + R} t ............... (1) where F is the driving force of the vehicle, M is the mass of the vehicle, V _b is the traveling speed, R _t of the vehicle represents the running resistance. The following relationship is obtained from equation (1). _{R t = F-MdV b /} dt ............... (2) That is, by the driving force F occurring in the vehicle pulling the inertial force MDV _b / dt of the vehicle, running resistance R _t is obtained.

The inertial force of the vehicle is _calculated by differentiating a vehicle speed detection value V _bdet obtained by a speed sensor (speed detection device 13) or the like attached to the shaft end of the traveling motor 7 into an acceleration obtained by differentiating the vehicle mass M And is expressed as follows: _{MdV b / dt = MdV b det} / dt Further, the driving force F is obtained by gradually in radius r of the wheel 11 to the torque T _m of a traveling motor 7 multiplied by the gear ratio Gr of the reduction gear 9, It is expressed as follows. F = T _m G _r / _r

[0018] In the moving electric motor control unit 5, the motor current i _q to be sent to the traveling motor 7 is a motor current command value i
_Suppose that it can be controlled to match _q ^* . In that case,
The main motor torque T _m is determined by multiplying the motor current command value i _q ^* to the nominal value [Phi _n of the torque coefficient of the traveling motor 7 is expressed as follows. T _m = Φ _n · i _q ^{* The} speed control device 3 calculates the running resistance R _t from the inertial force and the driving force F of the vehicle obtained as described above based on the equation (2).
Is obtained, and is expressed as follows. _{R t = T m G r /} r-MdV b det / dt Therefore, the torque for canceling the running resistance R _t, the target speed V _m ^* and the detected torque command value consisting of a torque corresponding to a deviation of the vehicle speed V _Bdet Motor control device 5 for running T _m ^*
, A constant speed deviation-running motor pattern is formed, and the vehicle speed can be made closer to the target speed.

FIG. 2 is a block diagram showing a specific example of the speed control method according to the present invention. The driving force estimation value F _est of the traveling motor is obtained by multiplying the main motor current command value _iq ^* by the nominal value Φ _n of the torque coefficient of the traveling motor 7 and the gear ratio Gr of the reduction gear 9 to obtain the radius of the wheel 11. obtained by Xu at nominal value r _n, it is expressed as follows. F _est = The ^{_{GrΦ n · i q * / r}} n, the estimated value of the inertial force of the vehicle, obtains the acceleration by differentiating the detection value V _Bdet vehicle speed detected by the speed detector 13, further vehicle mass nominal It is obtained by multiplying by the value _Mn and is expressed as: M _n dV _bdet / _dt Here, the running resistance estimated value R _test is the driving force estimated value F _est
Is obtained by subtracting the estimated value of the inertial force from the following equation, and is expressed by the following equation. When _{R test = GrΦ n · i q} * / r n -M n dV bdet / dt ............... (3) speed deviation compensator 15 is a proportional compensator compensating the driving force of the speed deviation, _Let K _p be the proportional gain and K _p
( _Vb ^* _-Vbdet ).

The torque command value T _m ^* is equal to the estimated running resistance R
_Test is multiplied by the nominal value of the wheel radius r _n to obtain the gear ratio Gr.
Is obtained as the sum of the estimated value of the running resistance torque reduced by and the compensation torque for the speed deviation. A value obtained by reducing the torque command value T _m ^* by the nominal value Φ _n of the torque coefficient of the traveling motor is the main motor current command value _iq ^* represented by the equation (4). ^{_{i q * = {R test +}} K p (V b * -V bdet)} / Φ n ............... (4) current control system, the power converter, the running motor current in traveling motor control device 5 comprising a motor circuit i _q is by being controlled to match the traction motor current command value i _q ^* obtained by the above procedure, conditioned traveling motor torque, as a result appropriate speed control is performed.

From equations (2), (3) and (4), i _q =
when i _q ^*, the following equation about the relationship of V _b and V _b ^* and R _t can be derived. ^{_{V b = K p ΦV b *}} / {Ms (Φ n -Φ) + Φ n M n s + K p Φ} + (Φ n -Φ) R t / {Ms (-Φ Φ n) + Φ n M n s + K p Φ ｝ (5) Here, s represents a differential operator.

In equation (5), the final value theorem (s →
0), a stationary relational expression is obtained as follows. If ^{_{V b = V b * + (}} Φ n -Φ) R t / (K p Φ) ............... (6) nominal value and the actual value is substantially the same, so can be regarded as Φ _n = Φ, ( The second term in equation (6) is zero. Therefore, the speed _Vb given from the traveling motor control device 5 finally matches the target value _Vb ^* .

FIGS. 3 and 4 are diagrams for explaining speed-torque characteristics in the embodiment shown in the block diagram of FIG. The horizontal axis represents the target speed V _b ^* of the vehicle and the current speed V of the vehicle.
_This is the speed deviation ΔV, which is the difference between _b . The vertical axis is the output torque of the traveling motor. In the figure, an upper right diagonal line (torque pattern) 31 or 35 is shown as a whole.
The torque pattern shows the relationship between the current speed deviation [Delta] V, the moving electric motor torque T _m to be output accordingly. The upper right area of the figure shows the current speed V rather than the target speed V _b ^*.
_This is a region where _b is small (the speed deviation is positive). In this region, except for a dead zone near the origin, control is performed such that as the speed deviation increases, the running motor torque increases substantially in proportion to the speed deviation. On the other hand, the lower left area is an area where the current speed _Vb is larger than the target speed _Vb ^* (the speed deviation is negative). In this region, the motor is controlled such that the larger the absolute value of the negative speed deviation becomes, the larger the absolute value of the negative speed deviation becomes (except for the vicinity of the origin), and the motor receives a braking torque proportional to the absolute value (the electric motor becomes a generator to apply a brake). .

FIG. 3 is a diagram for explaining the operation during power running.
When the running resistance torque 33a changes like 33b,
The speed deviation-torque pattern 31a is changed to a high torque pattern 31b as a whole. As a result, the change in the running resistance is compensated, and the speed deviation can always be kept near 0, and the vehicle speed can be controlled to the target speed. FIG. 4 is a diagram illustrating the operation during regeneration. When the running resistance torque 37a changes as indicated by 37b, the speed deviation-torque pattern 35a is changed to a pattern 35b having a lower torque as a whole. As a result, the vehicle speed can be controlled to the target speed always in the vicinity of the speed deviation 0 in proportion to the running resistance.

When the inertial force is obtained by differentiating the speed detection value in FIG. 2, a low-pass filter or the like may be used to remove the influence of noise and the like included in the speed detection signal. Although the present invention mainly describes a speed control method during traveling, the present invention can also be applied to stop control if the speed target value is set to 0 in combination with the vehicle position detecting means.

[0026]

As is apparent from the above description, according to the present invention, disturbances such as running resistance of a vehicle are estimated and compensated for, so that line conditions, vehicle speed and mass change. Also, the speed of the vehicle can be accurately controlled.
As a result, the load on the vehicle driver can be reduced. In addition, during unmanned driving, reliability in vehicle operation such as safety and punctuality can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an entire configuration of an electric vehicle having a vehicle speed control device according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a specific example of a speed control method according to the present invention.

FIG. 3 is a diagram illustrating speed-torque characteristics during power running in the embodiment of the block diagram of FIG. 2;

FIG. 4 is a diagram for explaining speed-torque characteristics during regeneration in the embodiment of the block diagram of FIG. 2;

FIG. 5 is a diagram illustrating the operation principle of constant speed control during powering of a conventional electric vehicle.

FIG. 6 is a diagram for explaining the operation principle of constant speed control at the time of a conventional electric vehicle during deceleration braking.

FIG. 7 is a diagram illustrating the operating principle of constant speed control during power running when the torque pattern is corrected based on the vehicle speed.

FIG. 8 is a diagram for explaining the operation principle of constant speed control at the time of deceleration braking when the torque pattern is corrected according to the vehicle speed.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 vehicle 3 vehicle speed control device 5 traveling electric motor control device 7 traveling electric motor 7a to d traveling electric motor 9 reduction gears 11a to d wheels 13 speed detector 21 differentiating unit 23 disturbance estimating unit 25 disturbance compensating unit

Claims (2)

[Claims] 1. A vehicle speed control device for controlling a vehicle speed to match a target speed by adjusting a torque of a driving motor; a vehicle speed detector; and a means for detecting or calculating a vehicle acceleration. Means for detecting or estimating the torque of the driving motor; means for estimating disturbance such as running resistance of the vehicle from the acceleration of the vehicle and the torque of the driving motor; and reflecting the disturbance in the motor torque. Means for controlling the vehicle speed. 2. The system according to claim 1, wherein a change in inertial force caused by a change in mass of the vehicle is compensated for as a disturbance.
The vehicle speed control device according to claim 1.