HUT66187A - Method for controlling the tractive and braking effort of motor vehicle - Google Patents

Description

The present invention relates to a method for controlling the traction motor or braking power of a traction motor of a motor train at the force limit of the wheels. In the process, the transition to the unstable slip range is detected based on greater acceleration of the wheels. The wheels are restored to a stable sliding range by reducing drive or braking force. Then the drive or braking power is reduced again and so on. The method employs an arrangement comprising a integrator (13) acting as a pseudo-jet shaft, in which the output quantity of the integrator (13) and the associated drive shaft rotational speed (f _ro t ^) serve as a measure of wheel slip.

reducing drive or braking torque; through a differential member (22), the first derivative of the speed difference in time to transition to the unstable slip range based on the greater acceleration occurring and upon activation of a limit step (43), an additional input of acceleration or deceleration input to the integrator anti-inlet volume is added until a return to a stable slip range occurs. In addition to reducing the traction or braking power by evaluating the speed difference (Δ ^η ), in addition to reducing the traction losses caused by the momentary force states, an additional reduction is applied, which is the first derivative of the speed difference (Z \ n) d ( depends on the maximum size you have just reached.

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Procedure for controlling the traction and braking power of motor vehicles

AEG Wstinghouse Transport-Systeme GmbH,

BERLIN, DE

Inventor: HAHN, Kari, BERLIN, DE

bej save

6/6/1993

International application number:

(PCT / EP93 / 01603)

The announcement

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MC λ 1- t I i Priority: 22.7.1992 (P 42 24 581.8) DE ko2, lc'Vc7e \ ₁ '\ X / L) (9) 7 / Z.

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The present invention relates to a method for controlling the drive and / or braking power of a traction motor of a power train. The adjustment is made at the force limit of the wheels. The transition to the unstable slip range is determined by the stronger wheel acceleration (wheel deceleration) that occurs. The bicycle or group of bicycles is then restored to a stable slip range by reducing the traction or braking force through the force closure maximum. After that, the driving or braking power increases again, and so on. In an arrangement containing an integrator acting as a pseudo-crankshaft, the difference in speed between the output quantity of the integrator and the rotational speed of an assigned drive shaft serves as a measure of wheel slip. Through a differentiator, the first derivative of the difference in time is detected by a transition to the unstable slip range based on the higher acceleration that occurs and, when a limit step is actuated, gives the integrator an additional input against the input of the prescribed acceleration or deceleration. until returning to the domain.

Such a process is already known from DE-PS 34 07 309. patent. This known process can be further improved by additional solutions, firstly, in DE-PS 38 37 908. Patent Specification No. 4,928,846 to the DE-PS 39 02 846 discloses a more accurate determination of the correct completion time of the additional input to the integrator. by the introduction of excitatory pulses which increase the responsiveness (actuation) of slippery track surfaces due to oil or other reasons.

However, there are still other operating states that still cannot be adequately addressed. These are processes where the force closure on the rails is eliminated very quickly or momentarily. Such is the cycling of a bicycle from a dry rail to a wet or lubricated part, whereby the maximum force closure is suddenly reduced to half or less, or it is driven from a stationary or low speed to rail surfaces where the force closure decreases steeply. rusty water). In these cases, the reduction in force from the Λ n-stroke results in very slow and unwanted large wheel slippages that can only be gradually eliminated with traction reduction.

The object of the present invention is to exclude or minimize traction losses in such special cases.

In accordance with the present invention, this object is solved by additionally applying, in addition to reducing the driving force or the braking force by evaluating the speed difference, a further reduction which depends on the maximum magnitude of the first derivative of the speed difference which is achieved.

Preferably, the portion of the first derivative of time exceeding a threshold value is stored in a maximum value library and reduced again to zero by a decaying function as soon as and until the time evolution of the first derivative of time is below the respective value of the maximum and decaying function.

Preferably, the decay function is an exponential function of the form f = U * r 'than when a capacitor discharges.

Here is an example of our invention! will be described in more detail by means of our figure. 1 is a schematic block diagram of a drive shaft control with an inverter-powered traction motor. The three-phase AC traction motor 2 is powered by the AC controller 1. For example, the shaft speed is detected by a speed measuring machine 3 (or a rotary pulse transmitter with a rating unit). The input is the derivative of the motor f _η slip ssoll frequency generated in the drive control. Instead of the vehicle's actual speed relative to the ground, the piston 5 is given a pseudo-crankshaft speed, which is compared to the measured shaft speed obtained from the speedometer 3 in a differential 6. The difference in speed produced by the difference divider 6 in a multiplier 7 is weighted by a suitable factor supplied at the connector 8, either constant or dependent on speed and / or traction. The value obtained in a subtraction unit 9 is subtracted from the prescribed value of the motor slip frequency fg _so j_j_ and applied as the prescribed value of the torque. In a priming unit 10, the frequency of the inverter is plotted as the sum of the rotational speed f _rot and the desired slip frequency of the motor as the stator frequency of the traction motor 2.

The nominal value of the expected acceleration or deceleration, which is derived from the traction force, the braking force and the weight of the vehicle, is given to the connector 11. In the case of locomotives, account must be taken of the coupled mixture (tow load), which may be achieved by automatic adaptation. This nominal value is integrated into a speed value in an integrator 13 acting as a pseudo-running axis. The integrator 13 is configured to integrate with a small tolerance range faster than the true acceleration of the vehicle so that the pseudo-crankshaft speed is approximately slowly ahead of the actual vehicle speed. A 13 • 4

- 5 - ...... ·· ··· The integrator therefore receives additional feed back on a comparator 14, switch positions 15 and 16, and a combination of rectifiers 17, 18 and other arrangements that always allow only one polarity, and an addition factor 12 over. Comparator 14 compares the output of the integrator, i.e., the pseudo-rotary shaft speed, with that of a real axis. The positive difference (i.e., the pseudo-crankshaft rotates faster) is passed only through the drive operating state (switch position 15 closed) to the integrator 13 via the coil rectifier 17, which then controls the pseudo-crankshaft down until it matches the actual shaft speed. The negative difference (i.e., the pseudo-crankshaft rotates slower) is passed through the braking state (switch position 16 closed) to the integrator 13 and this controls the pseudo-crankshaft upwards until it is equal to the real axis. Thus, as long as the actual shaft rotates, the integrator output will not accelerate or decelerate like the vehicle. The speed values are the same and there is no difference in speed between the 6 difference generators. In the event of a wheel slip, the axle will eventually accelerate more rapidly than the vehicle or the integrator during travel. The integrator 13 cannot now be driven through the recirculation because the combined rectifier 17 does not pass a signal of negative polarity. The difference generator 6 has a speed difference, such as between the drive shaft and a running shaft.

When braking, the polarity of the difference is reversed and thus the feedback signal passes through the switch position 16 and the rectifier 18. The speed difference signal in the 6 difference generators · «<

it then controls, as described above, the torque of the traction motor and thereby its traction or braking power.

Now, for example, the pseudo-cantilever rotation speed has reached a value that no longer corresponds to the speed relative to the ground, but to an axis that is already sliding on the rail and is needed to transmit the maximum possible traction. During this slip, that is, from the moment the drive shaft is cleanly rolling, the acceleration of the drive shaft is barely measurably greater than that of the vehicle. Greater acceleration of the drive shaft occurs only when the maximum friction coefficient is exceeded.

Without further steps, the pseudo-trailing axle integrator 13 would continue to run freely, while the pseudo-trailing axle would gradually become faster relative to the vehicle. The drive shaft slip would also get bigger and eventually spin out.

To prevent this, the control is designed to return the bicycle or group of bicycles back to the stable slip range by reducing the thrust (or braking force) of the engine Fjvjot during braking. Here, switch positions 19 and 20 and inverter 21 form a pole-changing unit which reverses the polarity of the speed difference signal in braking mode. The differentiation member 22 forms the first time derivative (d / \ n / dt) of the speed difference signal. The increase of the output signal of the differentiating member 22 makes the first type of delay member 40 slightly flatter. The output signal of the delay member 40 is then passed through a disconnect contact, electronically operated switch 41, to a threshold stage 43 which provides a binary signal to an OR gate 44. A callback leads to a 42 timestamp, which, after a response delay, opens 41 switches and then a further delay time has elapsed. and then close it again. This eliminates unwanted long signals for process control. The output signal of the OR gate 44 acts on a switch 31 and, via an inverter 45, on a first time slot reset (slot) input 46. The timing member 46 is a power-off delay member that is triggered by the output of the threshold 43. The first timestamp 46 initiates a second timestamp 47 which is a power-on delay member. The second timing member 47 operates an additional switch 48, which outputs the output of the maximum value selection stage 51 to a Schmitt trigger 52 and starts it. Thereby an additional signal can be transmitted to the OR gate 44 via a control switch 53. The maximum value selection stage 51 receives a direct input signal from the differentiation member 22 and an inverter 49 thereafter connected, and a further differentiated input signal through a third differentiation member 50. The maximum value selection stage 51 allows only the higher value of the two input signals. The control switch 53, through which the signal from the Schmidt trigger 52 is transmitted to the OR gate 44, is actuated by a start-up stage consisting essentially of a differential member 54, a summing unit 55, a differentiator 56, an inverter 57 and a threshold switch 58 available. Here we apply the measured rotational speed of the _rotary shaft and the pulling force F _Mot derived from the measured torque of the motor.

F _rot shaft speed is differentiated, a second differentiator 54 is fed to the bicycle axis accelerometer as switches through an adder unit 55 (directly, braking invertelve driving in). It derived from the measured electrically _dist torque M _Mot F for the adder unit • · * "···· · '·· • · · · · · · · · * • ·« _ ₈ .. · ·. · .. traction. The output signal of the addition unit 55 is the calculated traction force F _z , which is then transmitted to the rail by the wheel. In the event of a spin, a force distribution is created in which only a part of the traction force passes to the rail and an excess part accelerates the rotating mass of the wheels. Conversely, as the bicycle slows down, kinetic energy is released again to transmit traction and added to engine torque. Therefore, the kinetic energy of a bicycle must be taken into account when determining the actual traction power transmitted to the rail. This is done by adding to the add-on unit 55 the measured motor _acceleration F _Mot's traction force, which is also properly weighted with the weight of the bike (negative for running, positive for braking, as shown by elements 54, 59, 55).

The traction value thus determined is differentiated in a first differentiation member 56 and fed through an inverter 57 to a threshold switch 58 which controls the control switch 53. The threshold switch 58 is activated only when the output of the first differentiator 56 is negative, i.e., when the traction power is reduced. Thus, the OR gate 44 receives no further input signal at input b, nor does it output an output signal if there is no input signal at input a at this time. Thus, the first time member 46 is reset by slit input, and re-energized when an acceleration or deceleration initiates limit value 43 and actuates switch 31 through OR gate 44 to influence integrator 13, i.e., a spin sequence. It starts.

If there is a difference in speed between the 6 differentials, then the wheels, as described above, have exceeded the slippage on the rails that allows for the highest power transfer. The wheels enter the unstable slip range, which means that as the slip becomes larger, the traction numerical value again decreases. The increased torque then accelerates only a small rotational mass of the bicycle relative to the vehicle weight relatively quickly with the traction motor. The increase in the speed difference is detected by the differential member 22 and actuates the limit step 43 via the delay member 40 (to eliminate transient disturbances) and the switch 41. Its output signal actuates switch 31 via gate 44. Thus, at the input of the integrator 13, a signal is generated through the time step 32 and the adder 12, which is formed by the value of the expected acceleration at the connector 11 and a constant added to the adder 33 and inverted by the inverter 34. The time step 32 immediately passes a portion of the signal, allowing the remainder to be fully magnified with a first delay. The time step 32 does not include a trip delay for the signal as symbolically indicated. The integrator 13 thus becomes slower and, as soon as the auxiliary signal exceeds the direct signal, begins to integrate in the reverse direction. As a result, the pseudo-crankshaft rotation speed is reduced. As a result, the speed difference on the differential 6 is increased faster, but at the same time the traction motor torque decreases more strongly. This eliminates further acceleration of the bicycle; the bicycle begins to re-engage, ie returning to a stable slip range. As the speed of the bicycle approaches the pseudo-runner again, the speed difference signal on the 6 difference generators will again be reduced. However, the down control of the integrator 13 via the switch 31 must be maintained until the bicycle again reaches a stable slip range, that is, it returns to the maximum value of the adhesion value / slip curve. Otherwise, the system would remain in the unstable domain and eventually crash.

For this purpose, the Schmitt trigger 52 is responsive to inverter 49 for negative d / n / dt, i.e., reduction of the speed difference signal, and also transmits its signal to the OR gate 44. The Schmitt trigger 52 operates after the threshold 43 is triggered, the second timer 47 and the further switch 48 expire. Through the third differentiation member 50, through the maximum value selection stage 51, the Schmitt trigger 52 receives an additional forward signal, which allows it to sound even before the threshold level 43 falls again. This avoids a gap in the output signal of the OR gate 44 when the dA n / dt signal is zero-crossed. Alternatively, this can be achieved by the additional tripping delay of the threshold level 43, leaving out the differentiation member 50 and the maximum value selection stage 51. Because of the delay time of the second time member 47, the Schmitt trigger 52 can only sound when the threshold level 43 is turned on for this minimum time. Thereby, they have no further effect on transient disturbances that do not correspond to a real rollout sequence. The recovery time of the first timestamp 46 ensures that the Schmitt trigger 52 remains effective for a sufficient duration of the negative dA n / dt speed difference signal when the threshold level 43 is already deactivated.

·· ·· 4 · · · · · · · · · · · · · ·

···················································· Thus, the Schmitt trigger 52 maintains the auxiliary signal for the integrator 13 until the (nagative) d A ⁿ / dt signal returns to zero again.

The arrangement of the differential member 54, the addition member 55, the inverter 57, the threshold switch 58 and optionally the inverter 59, which always delivers a signal from the threshold switch 58 whenever the tractive force transmitted to the rails, is more accurately determined the time at which the bicycle starts to return to the stable slip range over the force limit. It is at this exact time that the signal is displayed on the threshold switch 58 and this switches off the signal remaining on the Schmitt trigger 52 via the control switch 53. As a result, the auxiliary signal of the pseudo-running axis integrator 13 is interrupted and the pseudo-running axis can be accelerated again.

According to the invention, this known arrangement is supplemented by a transmission member 80 and a maximum value store 81, indicated by a bold line. Preferably, the member 80 is a linear transmission member which initially has a dead zone. The maximum value store 81 includes a discharge circuit whereby a stored value, preferably by an exponential function, is reset to zero as soon as and until the input signal exceeds the instantaneous value. At the input of the transmission member 80, there is a differential frequency difference d Λ n / dt (the output signal of the differential member 22), the output side of which is connected to a maximum value store 81, the output signal of which is connected to the subtraction unit 9. The output signal is directly used for additional reduction by subtracting the torque from the set value ··· ♦ «« 4 4 · · 4.

The operating mode is as follows. A sudden acceleration of the wheels when running on wet or lubricated rails or when the force curve is already steep at a slight slip (such as sandy water) causes a momentary acceleration of the bicycle. Then z \ n grows very fast and the d / \ n / dt differentiated value will be much larger immediately than with normal slip processes. Thus, this value exceeds the dead zone of the transmission member 80, and the overshoot passes directly to the subtraction unit 9 via the maximum value store 81 and decreases the set thrust value. Due to the rapidly decreasing torque on the wheels, further acceleration of the wheels is eliminated even after a slight slip and the d 4 n / dt signal disappears again. The maximum value store 81 still maintains its signal with its decay time constant. If properly selected, the propulsive power loss decreases over time to the extent that it is replaced by a temporal normal process in the known arrangement, by reducing the pseudo-crankshaft revolution in the integrator 13, where sufficient reduction is required \ n created. The drive momentarily picked up the new reduced torque and now the known arrangement controls the drive as before. The present invention no longer intervenes, since in normal wheel slip processes the dead zone of the transmission member 80 is not exceeded by d / 1 n / dt.

Claims (3)

PATENT CLAIMS 1. A method for controlling the traction and / or braking power of a motor train at the force lock limit of the wheels, wherein the transition to the unstable slip range is determined based on the stronger wheel acceleration (wheel deceleration) occurring and the bicycle or bicycles restoring it to its maximum sliding range for a maximum period of time and then increasing the driving and braking forces again, and so on; an arrangement comprising an integrator (13) acting as a pseudo-crankshaft, wherein the speed difference (Δ n) between the output quantity of the integrator (13) and the associated drive shaft rotational speed ( ^f _rot ) serves as a measure of the wheel slip and evaluated; through a differential member (22), the first derivative of the speed difference in time to transition to the unstable slip range based on the greater acceleration occurring and upon activation of a limit step (43), an additional input of acceleration or deceleration input to the integrator providing an amount of anti-slip input until returning to the stable slip range, further comprising applying a further reduction in the reduction of the drive or braking force by evaluating the speed difference (Z \ ⁿ ), which is the first time difference in speed (Δη). derivative (d Δ ^η / ^) depends on the maximum magnitude that you have just reached. Method according to claim 1, characterized in that a portion of the time derivative (dA n / dt) exceeding a threshold value is stored in a maximum value library (81) and reduced again to zero according to a decaying function as soon as and as and when the time evolution of the first derivative of time is below the respective value of the maximum and the decaying function. A process according to claim 2, characterized in that a The decaying function of -1 / T is a function of F = U * e like when a capacitor is discharged.