JPH0213201A - High adhesion controller for electric vehicle - Google Patents

Abstract

PURPOSE:To enable effective usage of adhesion by judging the end of idle acceleration interval based on the start of deceleration of idling speed and droppage of the differentiated creep speed below a reference value. CONSTITUTION:A microprocessor 12 judges an idle acceleration interval and an idle non-acceleration interval based on a driving wheel circumferential speed VM, differentiated value VM thereof, vehicle speed VT and differentiated value VT thereof, and rises a strong adhesion control signal Tf quickly during idle acceleration interval while decreases the strong adhesion control signal Tf gradually during idle non-acceleration interval. Start of idling is detected based on the fact that the differentiated value of the creep speed (VM - VT) has exceeded over a reference value. End of idle acceleration is detected based on the fact that a predetermined time has elapsed after a time point when the differentiated creep speed has dropped below zero or a time point when the polarity of the differentiated driving wheel has changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an electric vehicle, and more particularly to a high adhesion control device suitable for effectively utilizing the adhesion between wheels and rails.

[Conventional technology]

Figure 10 shows the relationship between the creep speed (difference between the driving wheel circumferential speed VM and the vehicle speed v) V3 between the driving wheels and the rails and the frictional force (tangential force between the driving wheels and the rails) f. When the driving torque (or braking torque) of When f wax (f m & f is referred to as adhesion force) is reached and the driving torque (or braking torque) is further increased, the creep speed increases more and more, and as the creep speed increases, the frictional force f decreases to region B. (When creeping in area B, it is called idling, and when braking, it is called sliding.) If the creep speed at which the frictional force f reaches the maximum value f m & X is VsO, then V S - V S
o is called the idling speed when running, and the sliding speed when braking.

When slipping occurs, the system always detects this and reduces the drive torque (or brake torque) while the slipping speed is as low as possible to re-adhesion (reducing the slipping or sliding speed to zero), and By adaptively controlling the torque so that the torque is always close to the value equivalent to the adhesive force at that time, the inventors have developed an objective of effectively utilizing the adhesive force and preventing the adverse effects caused by slipping. Previously, several high adhesion control devices were proposed that were based on detecting the idling acceleration period and the idling non-acceleration period and giving an appropriate re-adhesion control signal for each period. , JP-A-60-91805, JP-A-61-170
207 and Japanese Unexamined Patent Publication No. 62-40004. In these technologies, the start of the slipping (or sliding) acceleration period is detected by the temporal change (differential value or difference) in the driving wheel peripheral speed VM or creep speed v3, and the end of the slipping (or sliding) acceleration period is detected. It is detected when the temporal change does not become a negative value or becomes less than a positive predetermined reference value, and the high adhesion control signal in the acceleration period is the high adhesion control signal in the adjacent area where the start of the acceleration period is detected. (as a result of the sum of the rapidly rising signals, the driving or braking torque is rapidly reduced), and the high adhesion control signal is gradually reduced during the non-acceleration period.

[Problem to be solved by the invention]

The high adhesion control device proposed earlier has no problems if the system lag is relatively large.

When the lag of the system is small, depending on the rail condition, the re-adhesion may not be sufficient and the rail may continue to slip (or slide), creating a problem in the effective use of adhesive force.

The purpose of the present invention is to solve the problem even when the lag of the system is small.

An object of the present invention is to provide a high-adhesive control device for an electric vehicle that always provides re-adhesive properties and enables effective use of adhesive force.

[Means to solve the problem]

The above object is achieved by determining whether the idling acceleration period has ended based on the fact that the idling speed has started to decrease and the differential value of the creep speed has become equal to or less than a negative predetermined reference value.

[Effect]

According to the present invention, when slipping occurs, the drive torque is reliably reduced to a value equivalent to the friction force between the driving wheels and rails at that time during the slipping acceleration period, and then gradually increased during the slipping non-acceleration period. By this, re-adhesiveness can be improved.

〔Example〕

The present invention will be explained in detail below. Dripping and skidding are essentially the same phenomenon, and similar measures are taken to prevent them. Therefore, below, the operation of an electric vehicle when moving will be explained as an example, and the only difference will be explained when braking.

FIG. 1 shows a block diagram of an embodiment of the high adhesion control device of the present invention using a microprocessor.

For simplicity, this figure shows a case where one main motor is controlled by one main control device.

In the figure, 1 is a torque command generating device, which generates a torque command Tp as an output. 2 is a main control device, which controls the torque generated by the main motor 3. There are various types of main control devices, such as a method that controls the firing phase angle of a thyristor in the case of an AC electric car, and a chopper control method and an inverter control method in the case of a DC electric car. Reference numeral 4 denotes a driving wheel circumferential speed detection device, which includes, for example, a speed generator attached to a driving wheel shaft or a rotating shaft connected to the driving wheel shaft, and its output waveform processing device, etc., and has an output proportional to the driving wheel peripheral speed VM. Generates voltage. This speed detection device also detects the passage of gears attached to the driving wheel axle, or the teeth or slits of a disk that is attached to a rotating shaft connected to the driving wheel axle and has a slit on its circumference. It is also possible to use a device that uses a sensor and converts the output of the sensor into a voltage proportional to the speed using a frequency-voltage converter.

4' is a vehicle speed detection device, for example, a speed generator attached to a driven shaft (shaft not driven by the main motor) and its output waveform processing device, etc., detects the vehicle speed V as an output.
It produces a voltage proportional to T.

Note that a ground speed detection device using a Doppler radar using ultrasonic waves or the like can also be used as the vehicle speed detection means. In some cases, these speed detection devices are provided with a filter to remove noise caused by vibrations while the vehicle is running. 9,9' is A-
This is a D conversion device that converts the driving wheel circumferential speed VM and vehicle speed VT into digital values, and the microprocessor 1
Enter 0. 11.11', 12 indicate the calculation contents in the microprocessor 10, 11 is the difference ΔVM of the driving wheel peripheral speed VM, that is, the driving wheel peripheral speed vM(n) at each time and the driving wheel peripheral speed vM before the sampling period. (
n-1) difference calculation unit. Δvs/Δts, which is obtained by dividing this ΔVM by the sampling period Δts, is the driving wheel circumferential acceleration V
Since it is equivalent to M, ΔVH can be used in place of vH.

Reference numeral 11' denotes a calculation unit for calculating the difference Δv7 in the vehicle speed VT, that is, the difference between the vehicle speed vr (n) at each point in time and the vehicle speed vt (n-1) one sampling period before.

ΔVT/Δt, which is ΔVT divided by sampling period Δts
Since s is equivalent to inter-vehicle acceleration v7, ΔVT can be used in place of VT.

Reference numeral 12 denotes a logic operation unit, which uses the driving wheel circumferential speed VM, the difference in the driving wheel circumferential speed ΔVH, the vehicle speed v, the vehicle speed difference Δv7, etc. to determine the slip acceleration period and the slip non-acceleration period, and to determine the rain period. Calculate the high adhesion control signal T□ at
This Ti is output.

13 is a D-A converter, and a microprocessor 10
The digital value TI, which is the output of
The main control bag r! is calculated. The torque generated by the main motor 3 is controlled via the main motor 12.

FIG. 2 shows the driving wheel circumferential speed VM, vehicle speed v7, creep speed vs, driving wheel circumferential acceleration VM, vehicle acceleration V7, creep speed differential value vx%, and for explaining the operation of one embodiment of the logic operation unit 12. It shows the change in readhesion control signal T'z over time. This figure shows the case of idling, where al is the driving wheel circumferential speed VM, and am is the vehicle speed V.
↑, b is creep VMt, 82 is vehicle acceleration V↑, d is creep velocity minute value y, (=vH-vt), and e is readhesion control signal T.

Each shows the change over time. As shown in the figure, when the differential value V3 of the creep speed exceeds the reference value δ1, the occurrence of slipping is detected, and the time at the moment when slipping occurs is set as tl. Differential value V of veri speed at time t1
The period until the time te when 3 becomes a negative predetermined reference value δ2 is called the idling acceleration period, and the variable 5LIP is set to 1 as shown in the figure.
far. During this idling acceleration period, in order to stop idling, the high adhesion control signal T1 is rapidly raised to quickly reduce the driving force. The period excluding this idling acceleration period is called the idling non-acceleration period, and the variable 5LIPti- is set to zero as shown in the figure. Therefore, the high adhesion control signal Tf is gradually decreased and the driving force is gradually increased. As shown in the figure, TI during the idling acceleration period is designated as Tia, and Tf during the idling non-acceleration period is designated as Tf-, the details of which will be described later.

FIG. 3 is a flowchart specifically showing the contents of the logical operation of the logical operation section 12. It is assumed that the variables used in FIG. 3 are zero when the microprocessor is initialized. Further, the symbol := means that the value on the right side of this symbol is recorded in the memory allocated to the variable on the left side. In Figure 3, 21 is 5L
It is determined whether IP is 1, that is, whether it is an idle acceleration period or not. If 5LIP≠1, that is, an idle non-acceleration period, the process proceeds to 22, where the creep speed V3 is compared with a reference value v16111. Here, V3sIn is a value corresponding to a noise component included in the speed detection device due to vehicle photography, etc., and is usually smaller than the creep speed VsOC (see FIG. 1) at which the frictional force becomes maximum. In 22, v
When s<v s@lB, it is assumed that it is an idle non-acceleration period, and the process proceeds to step 25, where the high adhesion control signal T ia during the idle non-acceleration period is calculated, and the result is stored in T1. In 22, when Vs≧VSml++, the process proceeds to 24, and in 24, the creep speed difference Δv
8 and the reference value δ1. Here, the creep speed difference Δ■5 is determined from the difference ΔVM−Δv7 between the driving wheel peripheral speed difference ΔVM and the vehicle speed difference ΔvT. Also, δ1
is a value corresponding to the reference value δ1 in FIG. 2, and is a constant equal to the product of δ1 and the sampling period Δt3. In 24,
When Δvs<61', it is regarded as an idle non-acceleration period and the process proceeds to step 25. In 24, when Δv5≧61', the process proceeds to 26, which is regarded as the start of the slip acceleration period (slip detection), and 5LI
P is set to 1, and the high adhesion control signal Tf at that point is TfI.
The high adhesion control signal Tz during the idling acceleration period is stored in
Perform the calculation of a and store the result in Tf.

At step 21, if 5LIP=1, that is, it is an idling acceleration period, the process proceeds to step 23, where the creep speed difference ΔVS is compared with a reference value 62'. Here, δ2 is a value equivalent to the reference value δ2 in FIG. 2, and is a constant equal to the product of δ2 and the sampling period Δts. In 23, Δv
When s<82', it is determined that the idle acceleration period has ended,
The program proceeds to step 28, where 5LIP is set to zero, the high adhesion control signal Tf4 is calculated during the idling non-acceleration period, and the result is stored in Tl. In 23, Δvs≧52
’, it is regarded as a idling acceleration period, and the process proceeds to 27.
The high adhesion control signal TI& during the idling acceleration period is calculated, and the result is stored in TI.

Noise components caused by vibrations included in the speed detection device tend to increase with vehicle speed, so 22 in Fig. 3
It is desirable that the reference value V3mIn used in the above increase with the vehicle speed.

The discriminator 22 in FIG. 3 can be omitted by taking measures such as providing a low-pass filter for removing noise components in the speed detection device and selecting an appropriate value for the reference value δ. However, by providing 22, malfunctions due to noise can be easily prevented.

In addition, FIG.
However, as is clear from Fig. 2, the differential value VM of the driving wheel circumferential speed and the differential value v of the creep speed have almost the same shape, so the difference in creep speed Δ
Instead of VS, the difference ΔVH in the peripheral speed of the driving wheels can be used, in which case 53' is a value equivalent to the reference value δ3 shown in FIG. 2, and is a constant equal to the product of δ8 and the sampling period Δts. .

The high adhesion control signal Tfa during the idling acceleration period is preferably the sum of the high adhesion control signal Tfi at the time of idling detection and a signal suitable for re-adhesion while the idling speed is at a minute value. Tra=Tzt+Gl-vst+Gz・vs+G3・V
Let S ・-m. Here, G1. Gz and Gs are constants representing gains, and VsO is a differential value of creep speed at the time of detection of slippage. The differential value V of the creep velocity is a peer-held value, that is, the previous value and the current value are compared at each sampling time, and the larger one is adopted.

The high adhesion control signal T1 during the idling non-acceleration period is decreased in a negative-order delayed manner, and T T x d + T mouth = 0 ・
...(2). Here, T is a constant representing a time constant.

The above is an example; Tza may be the sum of T i t and a signal that increases with time during the idling acceleration period, and the time constant T of Tzd is changed depending on the magnitude of T i a, When the driving force is sufficiently small, it is preferable to recover the driving force relatively quickly, and gradually recover the driving force near the adhesion force (maximum value of frictional force), and rather than decreasing it gradually. , may be decreased at a constant rate.

The high adhesion control device of the present invention has such a configuration, and after the idling starts to decelerate and the driving force is rapidly reduced until the differential value of the creep speed becomes equal to or less than a predetermined negative value, ! !
We are trying to gradually recover the driving force, so first,
It is possible to solve the problem that the re-adhesiveness of the proposed method may be insufficient.

Next, another embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 shows the temporal change in the differential value of the creep speed. In this embodiment, the period from when the differential value of the creep speed becomes zero until a time Δt elapses is defined as the idling acceleration period, and 5LIP = 1, and the logic operation unit for realizing this may be the portion surrounded by the broken line in FIG. 3 modified as shown in FIG. That is, the determining unit 23 determines the polarity of the creep speed difference ΔVS, and Δv
When 3 is O, proceed to 29. In 29, the sampling period Δts is added to the variable DT, and in 30, DT≦Δ
If t1, it is assumed that the idling acceleration period is in progress, and the process proceeds to 27. If DT>Δat at 30, it is assumed that the idling acceleration period has ended, and the process proceeds to 28.

At 28, in addition to performing the same calculation as at 28 in FIG. 3, DT is reset to zero. As described above, in this embodiment, the idle acceleration period ends after the time Δt1 has passed since the differential value vs of the creep speed becomes zero, so the delay time Δ
By setting t1 to an appropriate value, almost the same control as in the embodiment shown in FIG. 3 can be achieved. It goes without saying that Vstc'VM in FIG. 4 and Δvs in FIG. 5 may be returned to ΔV,
Even if it does so, it will have almost the same effect.

Next, another embodiment regarding wheel slip detection will be described with reference to FIGS. 6@ and 7. Figure 6 shows vH, v7 and V in Figure 2.
This diagram shows the time differential value VH of M, and in the example, VM
Although idling is detected when VM exceeds the reference value, idling can be detected when the second-order differential value VM exceeds the reference value δ5. In that case, a calculation unit for calculating the difference Δ(ΔVM) of ΔVM may be provided in the microprocessor 10, and the determination unit 24 in FIG. 3 may be replaced by A(Avx)k5s. Here, δ5 is a value obtained by multiplying the reference value δ5 by the square of the sampling period Δts.

Reference value No. 5 for VM must be greater than the vehicle running acceleration V↑, but since the main component of VH is the component due to idling, and VM is large at the time of VM startup, the Time Δt in Figure 6! , idling can be detected much earlier. Figure 7 shows vs and v in Figure 2.
This diagram shows the time differential value v5 of s, and in the example, Vs
Although slipping is detected when the reference value is exceeded, slipping can be detected when the second-order differential value Vs exceeds the reference value δB. In that case, a calculation unit for calculating the difference Δ(ΔVS) of ΔVS is provided in the microprocessor 10, and the determination unit 24 in FIG.
”:'. Here, 66' is the reference value δB
is multiplied by the square of the sampling period Δts. In this way, since V3 is large at the rise of vs,
By detecting the wheel slip using VS, the wheel slip can be detected as early as the time Δt3 in FIG. 7. By detecting slipping early in this manner, it is possible to suppress the slipping speed to a smaller value, and to control the driving force to a smaller value (adhesive force<maximum M of vibration force).

In addition, although the above embodiments have shown examples in which slip detection is performed using vs, the first or second derivative value of VW, or their equivalent values, the average value of the creep speed vso that gives the maximum frictional force is defined as vsopt, Creep speed vs.
When the value is equal to or higher than opt, it is possible to detect the occurrence of idle rotation.

shall be. Since v'go generally increases as the vehicle speed increases, * v! It is desirable that OPt be changed depending on the vehicle speed.

Next, an example in which a plurality of main motors are provided will be described in the eighth example.
This will be explained using figures. FIG. 8 shows the case of a locomotive equipped with a main motor stand.The main motors are divided into two groups of three, and each group is provided with an independent control device. In FIG. 8, only one group shows the entire constituent elements, and the group (■) shows only a part.

In FIG. 8, 31 to 36 are main electric motors, 41 to 46 are driving wheel circumferential speed detecting devices for the driving wheels having the respective main motors, and the maximum value of the driving wheel circumferential speed of each group is determined by maximum value detecting devices 51 and 52.

This maximum value is used as the VM in FIG. 1 of the present invention. Further, the minimum value of the driving wheel circumferential speed of each group is determined by minimum value detection devices 54 and 55. Then, the minimum value of the driving wheel circumferential speed of the other groups is used as the VT in FIG. That is, v7 of the first group is the minimum value of the tJ1 wheel circumferential speed of the n group, and v7 of the ■ group is the minimum value of the driving wheel circumferential speed of the first group.

Next, the contents of the calculation by the microprocessor 10 of this embodiment will be explained. 11.11' is a difference calculation unit, which calculates the difference ΔVM in driving wheel circumferential speed and the difference Δvs in creep speed, respectively.
Calculate. Reference numeral 12 denotes a logical operation unit that detects slipping and detects the end of the slipping acceleration period using ΔVH, and its output high adhesion control signal is designated as T t '. 12' is a logic operation unit that detects slipping and detects the end of the slipping acceleration period using ΔV3, and outputs a high adhesion control signal from Tf'.
The high value determining unit 53 determines the highest value Tz between T i ′ and T, and sets Tx as the high adhesion control signal for one group of this locomotive. With this configuration, when a small number of axes are idling, it is possible to detect the idling with high sensitivity using the high adhesion control signal by Δvs and perform fine control, while when all the axes are idling, Vs does not occur. , ΔVH generates a high adhesion control signal to cause all axes to re-adhese, making it possible to achieve sufficiently good high adhesion control. In this way, even without a coupling ring, good high adhesion control is possible regardless of the number of idling shafts. In the embodiment shown in FIG. 8, the minimum value of the circumferential speeds of the driving wheels of other groups is used as v7, but it may also be the minimum value of the circumferential speeds of all the driving wheels.

FIG. 9 shows an embodiment in which the traction motor voltage difference is used as an equivalent value of creep speed. In the figure, Rz and Rz are bridge resistances, 61 is a DC voltage detection device, and the traction motor 31. This device detects the voltage between the midpoint and the midpoints of the bridge resistors Rr and Rz, and inputs this voltage to the microprocessor 10 via the A/D converter 62. The output of the DC voltage detection device corresponds to each main motor voltage E1. E
A voltage proportional to the difference in x is obtained. When the creep speed is zero, El and Ez are approximately equal; however, if a creep speed occurs in any of the main motors, the back electromotive force of that main motor increases, and the output of the DC voltage detection device 61 is almost equal to creep. According to this embodiment, in which a voltage proportional to the speed can be obtained, as long as the main motors 31 and 32 do not idle at the same time, control can be performed in almost the same manner as in the embodiment shown in FIG. 1, and a speed detection device is not used. The device becomes simple. It goes without saying that the method using such a traction motor voltage difference is not limited to the case where two traction motors are connected in series as shown in FIG.

In addition, the above explanation has mainly been made regarding the case of slipping while driving, but considering that the driving wheel circumferential speed becomes smaller than the vehicle speed during braking, the creep speed v3 is calculated based on the vehicle speed v7 and the driving wheel circumferential speed VH. When using the difference V↑−VM, the differential value VM of the driving wheel peripheral speed, or the difference ΔvM of the driving wheel peripheral speed to detect the start of skiing and the end of sliding acceleration, the positive and negative polarities are reversed and the In the illustrated embodiment, the maximum value of the driving wheel circumferential speed of other groups is treated as the vehicle speed equivalent, and the minimum value of the own group's driving wheel circumferential speed is treated as the driving wheel circumferential speed equivalent.

〔Effect of the invention〕

According to the present invention, by simply improving the re-adhesion control unit, the adhesion force between the driving wheel rails can be used as traction force or braking force to the maximum extent possible, thereby improving adhesion performance and improving the adhesion performance of one locomotive. In the case of FI vehicles, the towing load can be increased, and in the case of FI vehicles, the number of motive vehicles in the illumination can be reduced,
In addition, since the acceleration/deceleration can be increased and the idling speed is suppressed to a minute value, it is possible to reduce wear on the driving wheels and rails and to improve riding comfort when idling occurs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the high adhesion control device of the present invention, and FIG. 3 is the logic of the logic operation section of the microprocessor, which is one of the components of the present invention. FIG. 4 is a flowchart showing the calculation contents, FIG. 4 is an explanatory diagram of the temporal change of the creep velocity differential value for explaining the operation of another embodiment of the high adhesion control device of the present invention, and FIG. A flowchart of the logical operation contents of the logical operation unit, FIG. 6 is an explanatory diagram of the operation of another embodiment of the high adhesion control device of the present invention, FIG. 7 is an explanatory diagram of the operation of another embodiment of the high adhesion control device of the present invention, 8 and 9 are block diagrams of embodiments of the present invention, and FIG. 10 is an explanatory diagram of the relationship between the creep speed VS and the frictional force f between the driving wheels and the rail. 1... Torque command generator, 2... Main control device, 3
゜31-36... Main electric motor, 4, 41-46... Driving wheel circumferential speed detection device, 4'... Vehicle speed detection device, 8.
...Subtractor, 9,9'...A-D converter, 10...
・Microprocessor, 11.11', 11'...
Difference operation section, 12.12'...Logic operation section, 13...
- D-A conversion device, 21 to 30... Each calculation block of the logical operation flowchart, 51.52... Maximum value detection device, 54.55... Minimum value detection device, 53... Maximum value detection Arithmetic unit, 60... Subtraction unit, vs... Creep speed, VM... Driving wheel peripheral speed, v7... Vehicle speed,
f...Frictional force, 7. /Tz', T□...High adhesion control signal, Tp...Torque command, ΔVM...Driving wheel peripheral speed difference, ΔVT...Vehicle speed difference, ΔVx...Creep speed difference, R1, RZ・・・Bridge Chime Kaya Tomoko C - Shield Town Mego Kayaya Hard Leather 7: Kaya δ Eye (Itori Toru Herim θ - Creep ° Green degree V)

Claims (1)

[Scope of Claims] 1. A means for detecting the circumferential speed VM or creep speed VS of the driving wheels, a means for detecting a change thereof over time, and a means for detecting the start of idle rotation and the end of acceleration of idle rotation using them; In a system that is divided into a slip acceleration period and a slip non-acceleration period, and the high adhesion control signal during the acceleration period is the sum of the signal T_f_i at the start of slip and a signal for suppressing slip, the detection of the end of the slip period is determined by the creep speed. The temporal change in driving wheel circumferential speed is below the negative reference value or above the positive reference value, and the temporal change in creep speed is zero. The scheduled delay time Δt has elapsed since the following happened, and the scheduled delay time Δt has passed since the polarity of the temporal change in the driving wheel peripheral speed changed.
A high-adhesive control device for an electric vehicle, characterized in that the control is performed by any of the following. 2. The start of the slipping is determined by the fact that the creep speed exceeds a reference value Vsopt that changes depending on the vehicle speed, that the differential value or a value equivalent to the differential value of the creep speed exceeds a predetermined reference value, and that the creep speed exceeds a predetermined reference value. The second derivative or the value equivalent to the second derivative exceeds the scheduled standard value, the absolute value of the differential value or the value equivalent to the differential value of the driving wheel circumferential speed exceeds the scheduled standard value, the second derivative of the driving wheel circumferential speed 2. The high-adhesive control device for an electric vehicle according to claim 1, wherein the detection is performed when the absolute value of the second-order differential value or the value equivalent to the second-order differential value exceeds a predetermined reference value. 3. Claim 1, characterized in that the maximum value of the circumferential speeds of the plurality of driving wheels during power running is used as the circumferential speed of the driving wheels, and the minimum value of the circumferential speeds of the plurality of driving wheels during power running is used as the vehicle speed. A high adhesive control device for an electric vehicle as described in Section 1. 4. Using the temporal change in the driving wheel circumferential speed, the high adhesion control signal T_f′ and the temporal change in the creep speed make the high value T_f of the high adhesion control signal T_f″ a high adhesion control signal. 5. A high adhesion control device for an electric vehicle according to claim 1. 5. A plurality of voltage differences controlled by the same main control device are used as the creep speed. A high adhesive control device for an electric vehicle as described in Section 1.