RU2426660C2 - Method of controlling multi-drive electric transmission of multi-axle wheeled vehicle - Google Patents

Abstract

FIELD: transport. ^ SUBSTANCE: invention relates to wheeled vehicles. Proposed method consists in setting required speed, determining angular speed setting for equivalent wheel, measuring current angular speed of drive motor of each wheel and adjusting angular speeds of all wheels. With actual angular speed of any wheel exceeding upper limit, electric power fed to wheel drive motor is reduced to tolerance. With actual angular speed of any wheel exceeding lower limit, electric power fed to wheel drive motor is increased to tolerance. ^ EFFECT: reduced losses in transmission and running wheels. ^ 4 cl, 5 dwg

Description

The invention relates to the field of wheeled vehicles, including multi-axle vehicles of large and especially heavy lifting capacity with individual electric wheel drives. The invention is intended to ensure the functioning of an automated control system (ACS) of traction electric motors (TED) of the motor-wheels of a wheeled automobile vehicle (ATS) with any wheel formula and with any rotation scheme. The multi-drive electric transmission control method provides for a steering angle sensor, a steering pole position sensor, a forward-reverse mode switch, a vehicle linear speed pedal angle sensor.

Closest to the claimed invention is a method of driving a motor vehicle, implemented in a torque control system of multiple wheels of a vehicle, including: one or more speed sensors in order to determine the speed for each wheel; an off-course acceleration sensor of a vehicle in order to determine an actual off-course acceleration of a vehicle; a torque sensor determines the direction of the vehicle and a predetermined amount of torque for the vehicle; an electronic monitoring device for processing data from speed sensors, an off-course acceleration sensor of a vehicle, an off-course acceleration sensor and a torque to generate torque signals for a plurality of wheels; and one or more torque signal generators responsive to the torque signals to change the torque, controlling each of the plurality of wheels so that the wheels provide either acceleration or deceleration depending on the intention of the driver and the traction provided (application US 2004176899) .

The control method implemented in this system is aimed at increasing the stability of the car, preventing yaw, including on surfaces with poor adhesion (wet asphalt, ice, etc.).

However, this control method is intended for cars 4 × 2 or 4 × 4, mainly cars, for which stability of motion is important, with a mechanical, hybrid or electric transmission. At the same time, the torques and angular velocities of the wheels are controlled respectively by mechanical, hybrid or electric transmissions with the implementation of the PBS / ABS function (ASR / ABS), i.e. excessive spin-up (slipping) of the wheels in the traction mode and blocking of the wheels in the braking modes are prevented, which is due to the properties of the mechanical differential transmission and electric transmission with the implementation of the so-called electric differential.

This control method is intended for use when driving at high speeds along a curved path, i.e. when issues of stability and controllability arise and are solved due to mechanical differential transmission or electric transmission with electric differential, different angular speeds of the wheels during curvilinear movement of the car, with different radii, due to manufacturing errors, different air pressure in tires, different load on wheel, wear, etc.

The claimed method is intended primarily for use on multi-axle all-wheel drive exchanges (8 × 8 or more), for which cross-country ability and economy are considered more important today and for them the most rational is the electric transmission with electric motor wheels, for the control of which this method is proposed .

One of the features of transmissions of such multi-axle all-wheel-drive exchanges is the occurrence of situations such as the spontaneous transition of some wheels from traction to braking (this is called “circulation” of power), which is naturally negative and must be avoided, which allows this control method.

The technical result of the control method consists in realizing the maximum possible traction forces on the wheels, in order to provide the most intense acceleration of the vehicle, if necessary, or to overcome the external forces of resistance to movement (difficult road conditions), and to minimize losses in the electric transmission and rolling wheels to minimize fuel consumption when controlling multi-axle all-wheel drive automatic telephone exchanges equipped with an electric transmission with electric motor wheels.

The basis of the proposed method is the follow-up control of each electric motor of the electric motor-wheel separately in angular velocity. The control of this method by one electric motor is known and well developed, the proposed method provides control of a multi-drive transmission, in which each of the wheels can be in different conditions for adhesion and rolling resistance.

The control method does not imply the movement of the PBX at high speeds, this is not necessary for multi-axis exchanges, so the stability and controllability of the exchange is not important. The maneuverability, traction, acceleration intensity and economy are important, which is provided in the proposed control method.

The technical result is achieved by the fact that in the method of controlling a multi-drive electric transmission of a multi-axle wheeled vehicle, it is provided that the driver sets the required speed of the multi-axle wheeled vehicle, converts the desired speed reference signal to the angular speed signals of the traction electric motors of the wheels, measures the current angular velocity of the traction electric motor of each wheel, determines direction of torque (which is much cheaper and more technically simpler it is hardware-based than measuring not only the sign - i.e., the direction of the torque, but also its numerical value, as in the application US 2004176899), comparing the indicated current angular velocity with the angular velocity corresponding to the said signal for setting the angular speed of rotation of the traction motor with the correction taking into account the radii of curvature of the circles along which the wheels move, when the machine moves along a curved section, the adjustment of the current angular speed of rotation of each wheel by adjusting the power supplied to yagovy electric wheel motor, and bringing the sign of its torque in accordance with the current mode of traction or braking of the wheel.

In this case, a range of angular rotational speeds of the traction electric motors of the wheels is set and the angular rotational speeds of the traction electric motors of the wheels are corrected within the specified range; the correction of the angular speeds of rotation of the traction electric motors of the wheels is carried out in a given period of time. It is possible to provide several dependences of the angular speed of rotation of the traction electric motor of the wheels on the position of the control element with the required speed of the wheeled vehicle, switching between which is carried out automatically according to a predetermined algorithm.

In the control method, three alternative options for preventing slipping of the traction wheels can be implemented. Thus, the correction of the angular speeds of rotation of the traction motors of each wheel during wheel slippage, which is carried out in the direction of decreasing the angular speed before the cessation of skidding, can be made using the ratio of the longitudinal acceleration of the body of the wheeled vehicle to the angular acceleration of each wheel as a controlled quantity; the value of the slip coefficient of each wheel, determined by the ratio of the angular velocity of the wheel and the linear speed of the wheeled vehicle; slippage coefficient and torque of each wheel.

The use of servo control of each electric motor-wheel according to its angular speed allows avoiding their spontaneous promotion, which happens, for example, in mechanical differential transmissions. But the speeds of all wheels must be set individually. To this end, the method describes the procedure for forcing various angular velocities of the wheels upon curved movement of the ATS, at their different radii, due to manufacturing errors, different tire pressures, different wheel loads, wear, etc.

Figure 1 shows the dependence of the "settings" USEC from the angle of deviation of the angular speed control pedal: ω _keu = K _шli · α, in mode 1.

Figure 2 shows the dependence of the "settings" USEC from the angle of deviation of the pedal control the angular velocity ω _key = K _W2 · α, in mode 2.

Figure 3 shows a graph of changes in the time constant (in the control loop USEC ω _KEU ) for mode No. 2.

Figure 4 shows a graph of the change in the value of the time constant for mode 3.

Figure 5 shows the dependence of the "settings" USEC from the angle of deviation of the angular speed control pedal when reversing.

Adjustable values are the angular speeds of all wheels of the ATS.

Objectives of the method: Using the advantages of an individual electric drive of wheels, create conditions for the most efficient implementation of both the traction and coupling capabilities of each wheel of the ATS and the capabilities of the TED to ensure:

1. The implementation of the maximum possible traction forces on wheels, if necessary, to ensure the most intense acceleration of the vehicle or to overcome the external forces of resistance to movement (difficult road conditions).

2. Minimization of losses in ET and rolling wheels to minimize fuel consumption.

Devices that form the input information for self-propelled guns:

1. Steering wheel (setting the direction of movement of the vehicle).

2. Positioner of the position of the pole of rotation (used to set the position of the pole of rotation on the longitudinal axis of the vehicle).

3. The switch of the "forward-backward" driving modes is located on the control panel.

4. The mode switch K _w (used to set one of the four modes No. 1, 2, 3 and 4 of the forward movement of the ATS) is located on the control panel. The presence of four modes is explained by the need for simulation and experimental testing of the modes. The choice of the optimal one should be made in each specific case, depending on the requirements and operating conditions of a particular automatic telephone exchange, using the method proposed by the author.

5. Angular speed control pedal (used to set the angular speed of the equivalent ATS wheel).

6. Brake control pedal (used to set the braking forces developed by the braking mechanisms of the ATS, and is not used in the ET control method).

The equivalent wheel angular speed (USEC) is understood as the angular speed of a hard wheel of ideal geometry (having a rolling radius in free mode equal to the nominal value, _rc = 0.52 m), located in the middle of the base on the longitudinal axis of symmetry of the ATS and the plane of rotation which coincides with the instantaneous velocity vector of a given point on the machine (i.e., the wheel rolls along the trajectory of the ATS and its plane of rotation is tangent to this trajectory).

The driver, controlling the automatic telephone exchange through the controls, sets the direction of movement and linear speed. In motion, the wheels may find themselves in different traction conditions, then for the maximum realization of the traction and coupling capabilities of each of the wheels it is necessary to set different slippage through the regulation of the speeds of rotation of the wheels. It is simply impossible for the driver to set different speeds for each of the wheels. You can require him to control the linear speed of the ATS using the controls and according to the feedback, which is the speedometer and a visual assessment of the speed driver. In light of this, the concept of USEC is introduced to create a method for controlling the angular velocities of wheels of ATS and its adequate understanding. For this method, we assume that the driver by deflecting the angular speed control pedal will set the automatic control system linear velocity of the ATS, which will be the product of USEC and the static wheel radius of ideal geometry.

2 Forward

2.1 the formation of the source information

To move forward, the driver moves the toggle switch of the "forward-backward" movement to the "forward" position. After this deviation, the angular speed control pedals are unambiguously interpreted by the self-propelled guns as the driver’s command to move the vehicle forward. Switching the toggle switch of the "forward-backward" driving modes is possible only on a fixed telephone exchange, i.e. the measured angular velocities of all wheels are less than or equal to ω _Kiism ≤ ± 0.01 rad / s; in case of accidental switching of the toggle switch during movement, a hardware lock is provided with the light alarm on the control panel.

2.2 the calculation of the angular velocity of the equivalent wheel

The driver sets:

1. USEC change: α [°] - the angle deviation of the angular speed control pedal;

2. The curvilinear movement of the ATS by changing: φ _pk [°] - the angle of rotation of the steering wheel and γ _p [position] - the positioner of the pole position;

3. One of the four modes No. 1, 2, 3, and 4 of the forward movement of the ATS — by the mode switch K _w (4-position switch).

2.2.1 the mode of movement of the layout No. 1

The switch modes of movement ATS K _w is in the first position. The dependence of the "setting" of the USEC on the angle of deviation of the angular speed control pedal is considered linear [rad / s]:

The deviation angle of the angular speed control pedal α [°] varies within [0, 60 °]. The largest USEC ω _kemax corresponds to the largest pedal deflection angle α _max = 60 °.

To increase the sensitivity of the USEC control when driving at low vehicle speeds, five rolling sub-modes of the equivalent wheel are introduced, which is some analogue of a multi-stage transmission. They are characterized by a coefficient K _W1i (i = 1.5). The values of the coefficients K _W1i are shown in table 1.

The dependences ω _keiu = K _W1i · α are shown in _figure 1.

Table 1 The values of the coefficients Ksh _1i i _Ch , rad / s ° ω _keyimax , rad / s ω _keyimin , rad / s one 2 3 four one 0.057 3.24 0.00 2 0.17 10.20 1.70 3 0.34 20.40 3.40 four 0.57 34.20 5.70 5 0.94 56.40 9.40

The control method in mode No. 1 operates as follows. When the angular speed control pedal deviates from the zero position by the angle α, the ACS initially selects the _{sub mode} K _w11 (corresponds to the minimum USEC ω _kemax1 [rad / s] with the maximum deviation of the angular speed control pedal). With a further deviation of the pedal (with an increase in the value of α), the ACS increases the value of the “setting” ω _ke1 according to formula (1).

The transition to the _{sub mode} K _W12 (or K K _{W1i + 1} ) is carried out under two conditions:

1. Upon reaching the measured USEC, ω _{keism of} its maximum value with a tolerance of ± 2%, for the submode K _w12 (K _w1i ) it is ω _kemax1 ± 2% (ω _kemaxi ± 2%, see Table 1).

2. When the USEC pedal is in the maximum deviation with a tolerance of ± 2%, α = α _max = 60 ± 1.2 ° (which corresponds to the maximum value of the "set point" ω _kei = (ω _keimax ).

After the transition to K _W12 (K _{W1i + 1} ), there is a further increase in ω _keism until the value corresponding to the angle of the driver deflects the angular speed control pedal (until the value of the “setting” ω _{keu is reached} ).

In the case of a decrease in the angle α by the driver, a decrease in ω _{keism is} performed by ACS according to dependence (1) for the currently selected K _w1i (for example, K _sh12 ) until the value corresponding to the angle of the driver deflects the angular speed control pedal (until the value of the “setting” ω _keu .

The transition to K _W1i-1 (in our example K _W11 ) is carried out under two conditions:

1. Upon reaching the measured USEC ω _{keism of} its value, which is equal for the submode K _w1i ω _keimin ± 2% (see table 1).

2. When the USEC pedal is deflected in the position α = 10 ± 1.2 ° (which corresponds to the minimum value of the "setting" ω _kei = ω _keimin ).

ACS calculates the value of the measured USEC ω _keism to verify the fulfillment of the first condition for the transition from K _W1i to K _{W1i + 1} (and from K _W1i to K _W1i-1 ) according to the formula:

where ω _keism is the measured value of USEC (real value) [rad / s];

ω _kjism is the angular velocity of the j-th wheel obtained from the angular velocity sensor of the j-th TED [rad / s];

K _vj is the coefficient of correction of the angular velocities of the TED during curvilinear motion, depending on the angle of rotation of the steering wheel and the position of the steering pole setter. In a rectilinear motion (φ _pk = 0 and γ _p = 0) K _vj (φ _pk , γ _p ) = 1. This coefficient allows you to almost completely avoid the "circulation" of power in the transmission and tire wear during curvilinear movement of the ATS.

To _ωj is the coefficient of the additional increment of the angular velocity of the j-th wheel (its values are given below);

n is the number of PBX wheels.

In this case, ω _keism may differ from the value of its “setting” ω _{keu by} no more than ± Δω _keiism rad / s, which is given in table 2 for each of the five submodes.

table 2 i ω _keyimax , rad / s Δω _keyism , rad / s one 2 3 one 3.24 0.20 2 10.20 0.50 3 20.40 1.10 four 34.20 2.00 5 56.40 3.00

Extremely rapid increase in torque on the TED (due to the instantaneous summing up of high electric power), in the event of a sharp deviation by the driver of the USEC pedal to the maximum position, can lead to: significant dynamic loads in the drive and the carrier system of the layout; to disruption of the soil under the wheels with a possible subsequent loss of mobility. To prevent this, an inertial link with a time constant T = 1 s is introduced into the control loop of the USEC ω _ke . This will lead to a smooth increase in the power supplied to the TED to the value set by the self-propelled guns for a time greater than or equal to 3 s. This inertial link is similarly present in the modes of movement No. 2, 3, and 4, as well as when reversing.

2.2.2 Mode No. 2, 3 and 4

In the formation of ACS USEC modes No. 2, 3 and 4 are the same. Therefore, the following description equally applies to both mode No. 2 and modes No. 3 and No. 4. The difference in modes is presented in clause 2.3.

The switch of the modes of movement of the layout K _W is in the second (third or fourth) position. The dependence of the "setting" of USEC on the angle of deviation of the angular speed control pedal is considered linear:

where K _w2 = 0.94

The deviation angle of the angular speed control pedal α [°] varies within [0, 60 °]. The largest USEC ω _kemax = 56.4 rad / s corresponds to the largest pedal deflection angle α _max = 60 °. Moreover, ω _keism may differ from the value of its “setting” ω _{keu by} no more than ± Δω _keism rad / s, where Δω _keism = 3 rad / s. The dependence of ω _keu shown in _figure 2. As in clause 2.2.1, an inertial link with a time constant T = 1 s is provided.

2.3 Regulation of angular speeds of wheels

Regardless of the selected driving mode No. 1, 2, 3 or 4 (that is, regardless of the position of the switch K _W ), the angular speeds of the wheels are set by the self-propelled guns relative to the "setting" USEC ω _{keu in a} single way. In this case, the reduction of the measured angular velocity of the i-th wheel (ω _kiizm ) of the ACS produces by reducing the electric power supplied to the TED of the wheel (up to a complete shutdown), the angular speed is increased by increasing the power supplied to the TED.

The angular speeds of all wheels are regulated by self-propelled guns equal to the “setpoint" of the USEC, adjusted for K _Vi (φ _рк , γ _п ) with an accuracy of regulation of no worse than ± 0.1 rad / s from the set value ω _кiу [rad / s]:

where ω _кiу is the value of the angular velocity of the i-th wheel (the value of the "ACS" setting) [rad / s].

That is, all ω _kei are equal to each other with a control error of ± 0.1 rad / s (for K _Vi (φ _pк , γ _п ) = 1) and equal to ω _keism , which, in turn, is set according to ω _keu with a control error of ± Δω _keyism rad / s (ω _keyism = ω _key ± Δω _keyism rad / s).

When the value of the angular velocity of any wheel ω _kiizm (real value) _goes beyond the upper tolerance limit (more than +0.1 rad / s from ω _kiu ), the ACS reduces the electrical power supply to its TED (up to its complete shutdown) until ω _{kiizm enters} into permissible corridor, then continues to bring power to this wheel. When the value of the angular velocity of any wheel ω _kiiz out of the lower tolerance limit (less than -0.1 rad / s from ω _kiu ), the ACS increases the sum of electric power to its TED until ω _{kiizm enters} the permissible corridor.

This eliminates the "circulation" of power between the wheels. In the case of “circulation” of power, the longitudinal reaction in the contact patch of the wheel changes its direction and becomes not the driving force of the vehicle, but the force of resistance to movement. To prevent such a phenomenon, this method of regulating the angular speed of rotation of the wheels is proposed, which can be cited as some analogy mechanical locked transmission with freewheels on each wheel.

However, this method of controlling the angular speeds of rotation of the wheels, as well as a similar mechanical blocking transmission with freewheels, has a significant drawback. The rolling radii of the wheels in free mode can take different values, this can be caused by differences in wheel sizes (due to size tolerance, wear during operation, etc.), normal loads on them, air pressure in tires, kinematic discrepancy in the transmission, as well as their movement along various trajectories in corners. Neglecting dynamic (short-term) changes in the radii of free rolling of the wheels and taking into account only their static (long-term) changes, we consider only the static change in the radii of rolling of the wheels caused by this in the driving mode. Consequently, wheels with large rolling radii will be somewhat overloaded with longitudinal reactions, and wheels with smaller rolling radii of self-propelled guns will be put into slave driving mode (their TED will be disconnected from the power supply) due to the fact that they will rotate at a greater angular velocity than traction wheels. This can be avoided by identifying the TEDs disconnected from the power supply, and forcibly setting them a slightly higher rotation speed than the one with which they rotated in the slave mode. This will make it possible to transfer these wheels from the driven driving mode to the driving one, which, of course, will increase the traction capabilities of the vehicle and distribute the longitudinal reactions along the wheels in a more rational way. Otherwise, a significant redistribution of longitudinal reactions is possible. In addition to overloading the tires of these wheels and increasing internal energy losses in them, this can cause the longitudinal reactions of the traction wheels to exceed the limit of adhesion to the supporting surface and, accordingly, the loss of mobility. To avoid this phenomenon, the following is proposed.

Continuously (with the step of calculating self-propelled guns) to interrogate each wheel from the moment the wheel reaches the angular velocity ω _kiiz ≥ 0.1 rad / s for the fulfillment of the criterion consisting of three conditions:

1. The angular speed of the wheel, measured by the sensor ω _kiizm , exceeds the "setting" ω _{kiu by} more than 0.1 rad / s for a period of time Δt> 3c (there is a difference Δω _kiizm = ω _{kiizm -ω kiu} > 0.1 rad / s);

2. Linear acceleration of the ATS a _x <2 · Δ _a ;

3. The angular velocity of rotation of the wheel ω _kiizm <1.1 · ω _kiu .

Where Δ _a - measurement error of the linear acceleration sensor ATS.

Moreover, according to the control method, electric power should not be supplied to this wheel TED.

If these three conditions (1 ... 3) are fulfilled, a new value of the "set point" of the angular velocity equal to:

This change in angular velocity will make it possible to more evenly distribute the longitudinal reactions along the wheels of the vehicle.

The coefficient K _{ω the} additional increment of the angular velocity is equal to:

1. For the mode of movement No. 1 and 2 - K _ω = 1.04;

2. For driving mode No. 3 and 4 - K _ω = 0.5 · (ω _keism + Δω _kiism ) / V _a , while there are limitations To _ω <1.1.

The difference in the determination of K _ω is due to the fact that for the movement modes of ATS No. 3 and 4 it is necessary to determine the absolute speed of movement, determined by the sensor, but in modes 1 and 2 this is not necessary. Therefore, it was decided for the first two modes to set K _ω as a constant, and in other cases to calculate the linear speed of the ATS through the angular speeds of the wheels.

The new value of the "setting" of the angular velocity ω _{kiu is} maintained for 600 s, then it is again set according to formula (4) and the criterion (1 ... 3) is checked again. If these conditions are met for the third time, ω _kiu is determined by the self-propelled guns according to formula (5) until the automatic telephone exchange is completely stopped. This is intended to create feedback for this criterion in order to prevent excessive spinning of some wheels, that is, protection against overshooting of the system.

The conditions (1 ... 3) of this criterion are selected from the following considerations:

1. A time delay of 3 s is used as a time filter. ACS does not work out transients of changes in the angular velocity of rotation, but only responds to their static change.

2. The condition for minimizing linear acceleration is chosen for the self-propelled guns not responding to changes in the longitudinal reactions of the wheels during acceleration or deceleration of the vehicle.

3. The limitation on the angular velocity of rotation of the wheel ω _ki serves as protection against control of the wheel in the event of a significant increase in its angular velocity. For example, the wheel has significant damage, and it is not practical to load it with a longitudinal reaction.

Distinctive features of modes No. 2, 3 and 4:

In the case when the driver sharply increases the “setting” of the USEC, a rapid increase in torque on the TED is possible due to the supply of high electric power, which can lead to significant dynamic loads in the drive and the host vehicle system and to the disruption of the soil under the wheels with a possible loss of mobility . This is due to the dependence of the coefficient of adhesion on solid supporting surfaces and cohesive soils with a pronounced maximum. To realize the maximum possible traction force, each wheel was limited by the angular speed of the wheels in three different ways.

When implementing regime No. 2.

The time constant (in the control loop USEC ω _KEU ) for mode No. 2 changes according to the graph of figure 3 and table 3.

Table 3 Δ T, s 0 one 5 one fourteen 5 28 eighteen 160 eighteen

where Δ = (ω _{keukon -ω key value} ) / ω _{key value}

ω _{key value} is the measured value of USEC at the time when the driver changed the “setting” of the wheel by more than 0.25 rad / s;

ω _keukon is the value of the "set" of the USEC given by the angle of deviation of the angular speed control pedal at this point in time.

That is, when ω _kiu remains constant unchanged (the driver does not press the angular speed control pedal) T = 1 s, with increasing ω _kiism to ω _kiukon (the driver pressed the angular speed control pedal and the self-propelled _gun works this) change the slew rate ω _{kiism by} changing T, according to the above data.

Continuously (with a step of ACS calculations) to poll each wheel from the moment of:

1. Achievements by the wheel of angular velocity ω _keiizm ≥0.1 rad / s;

2. Achievements by the wheel of angular acceleration ε _i ≥0.05 rad / s ² ;

On the subject of the conditions for each of the wheels:

where a _x is the linear acceleration of the ATS [m / s ² ];

ε _i - angular acceleration of rotation of the i-th wheel [rad / s ² ].

The limitation of the ratio of linear acceleration to angular has a dimension [m] and it can be interpreted as the values of the rolling radius of the wheel. Thus, for a tire of this dimension r _k = 0.6 m corresponds to a wheel slip of about 20 ... 23%, which, according to most studies, is close to the maximum grip value.

ATS linear acceleration is read from the acceleration sensor. The angular acceleration of rotation of the i-th wheel is obtained by differentiating the angular velocity of the wheel.

If the condition is met, the “set point” of the angular speed of rotation of the i-th wheel ω _{kiu is reduced} until the moment _x and ε _i ≥0.4 are satisfied:

where ω _{kiу_change} is the changed "setting" of the angular speed of rotation of the i-th wheel ω _kiu [rad / s];

Δω _{kiу_change} - a change in the "setting" of the angular speed of rotation of the i-th wheel ω _kiу .

At the same time, an inertial link with a time constant T is introduced in the control loop Δω _{kiу_change} .

where N _a is the transfer function of the inertial link with a time constant T = 4 s;

t _e is the relative time in the self-propelled guns counted from the moment the criterion a _x / ε _i <0.4 is met (i.e., at the time when a _x / ε _i = 0.4 t _e = 0 s and each time the criterion passes after 0.4, the parameter t _e is reset) [s].

This criterion makes it possible to determine the moment of the start of wheel slippage, if the driver, setting the USEC ω _ke , made a mistake and exceeded the wheel's ability to grip, it is used according to print data in modern traction control systems (PBS). It implements the limitation of wheel slippage and maintaining the traction forces of all wheels as high as possible. This method of regulating wheel slippage can be called: a method of regulating wheel slippage according to the forecast of possible slipping.

When implementing mode No. 3, continuously (with the step of calculating the self-propelled guns) to interrogate each wheel from the moment the wheel reaches the angular velocity ω _keiism ≥0.1 rad / s for the fulfillment of the conditions for each of the wheels:

where S _i - slippage of the i-th wheel, is calculated by the formula:

If the condition is met, a change in the value of the time constant is carried out according to the graph of figure 4 and table 4.

where Δ = (ω _{kiukon -ω kivac} ) / ω _kivac

ω _kiiznach - the value of the angular velocity of the wheel at time S _i = 0,15.

ω _kiukon - the value of the "setting" of the angular velocity of the wheel at time S _i = 0.15, given the angle of deviation of the angular speed control pedal at this time (S _i = 0.15).

That is, when ω _kiu remains constant without change (the driver does not press the angular speed control pedal), Т = 1 s, with increasing ω _kiizm to ω _kiukon (the driver pressed the angular speed control pedal and the self-propelled _gun works out) at the moment of execution of S _i > 0.15 to change the slew rate ω _{kiism by} changing T, according to the above data.

Table 4 Δ T, s 0 one one one 5 1.25 10 3 fifteen 6 28 eighteen 160 22

When S _i reaches 0.19:

In this case, the slippage value was selected on the basis of numerous experimental studies, from which it follows that the maximum adhesion (curve φ (S)) for most surfaces is in the range of S values from 0.15 to 0.25. The choice of the value of the slip coefficient of 0.15 is due to the lower limit of the maximum grip, and 0.19 as the average value of this range (margin of 0.01 in case of slight overshoot of the wheel slip system).

In addition, it is possible to determine S _before the actual maximum of the curve φ (s) through the value of the longitudinal reaction of the wheel Rx, which can be determined using sensors or indirectly estimated by the torque.

If the condition is fulfilled, the “set point” of the angular speed of rotation of the i-th wheel ω _{kiu is reduced} until the moment when the wheel slippage becomes less than 0.19 according to the following dependence:

This condition is a limitation of the angular velocity of rotation of each wheel for a given slip. This allows you to individually adjust the slippage of each wheel to the optimum range. In this embodiment, the wheel slippage is limited and the traction forces of all wheels are kept as high as possible. This method of controlling wheel slippage can be called: a method of directly regulating wheel slippage.

When implementing regime No. 4.

The time constant (in the USEC loop ω _keu ) for mode No. 4 is assumed to be constant and equal to T = 1 s.

Continuously (with the step of calculating the self-propelled guns) it is necessary to interrogate each wheel from the moment the wheel reaches the angular velocity ω _keiizm ≥0.1 rad / s for the fulfillment of the conditions for each of the wheels:

If the condition is fulfilled, the self-propelled gun takes the current value of the wheel torque as the limit:

In the future, self-propelled guns maintain the torque of this wheel no higher than this limit value:

If after t = 30 s after the time moment M _TEDi = M _TEDiconst the condition is satisfied:

Then all the restrictions on the torque on the i-th wheel are removed. The choice of the limit values S in 0.15 and 0.19 is similar to the choice in mode No. 3.

This condition is a limitation of the angular speed of rotation of each wheel for a given slip using torque on the TED. This allows you to individually adjust the torque of each wheel, avoiding exceeding the clutch limit. This option implements the limitation of the torque of the wheels and maintaining them as high as possible. This method of regulation can be called: a method of regulating directly the torques of the wheels.

3 Reversing

3.1 the formation of the source information

To move backward, the driver sets the toggle switch of the "forward-backward" movement to the "backward" position. After this deviation of the angular speed control pedal, the self-propelled guns are unambiguously interpreted as the command of the driver to move the vehicle back.

3.2 the calculation of the angular velocity of the equivalent wheel

The driver sets when moving back:

1. USEC by changing α [°] - the angle of deviation of the angular speed control pedal.

2. The curvilinear movement of the ATS by changing φ _pk [°] - the angle of rotation of the steering wheel and γ _p [B] - the positioner of the position of the pole of rotation.

The dependence of the "setting" of USEC on the angle of deviation of the angular speed control pedal is considered linear:

where K _shzkh = 0.09

The deviation angle of the angular speed control pedal α [°] varies within [0.60 °]. The largest USEC ω _kemax = 5.4 rad / s (while the speed of this prototype of the vehicle is 10 km / h) corresponds to the largest pedal deflection angle α _max = 60 °. Moreover, ω _keism may differ from the value of its “setting” ω _keu not more than ± Δω _keism rad / s. Where Δω _keismism = 0.2 rad / s.

The dependence of ω _keu = K _SHZH · α is shown in _Fig.5 .

3.3 Regulation of angular speeds of the wheels

The angular velocities of all wheels are regulated by self-propelled guns equal to the “settings” of the USEC adjusted for K _Vi (φ _pk , γ _p ) with a control accuracy of no worse than ± 0.1 rad / s from the set value ω _kiу :

That is, all ω _kei are equal to each other with a control error of ± 0.1 rad / s and are equal to ω _keism , which, in turn, is set by self-propelled guns according to ω _keu with a control error of ± Δω _keism rad / s (ω _keism = ω _key ± Δω _keism glad / s).

When the value of the angular velocity of any wheel ωki _ism (real value) goes beyond the upper tolerance limit (more than +0.1 rad / s from ω _кiу ), the ACS reduces the electrical power supply to its TED until ω _{kiism enters} the allowed corridor (up to a complete shutdown) , then continue to bring power to this wheel. When the value of the angular velocity of any wheel ω _kiiz out of the lower tolerance limit (less than -0.1 rad / s from ω _kiu ), the ACS increases the sum of electric power to its TED until ω _{kiiz enters} the permissible corridor.

Claims (4)

1. A method for controlling a multi-drive electric transmission of a multi-axle wheeled vehicle, which consists in setting the driver, depending on the angle of the pedal deflection and the driving mode, of the required speed of the wheeled vehicle, determining the value of the equivalent angular speed setting of the equivalent wheel (USEC), which means the angular speed of the hard wheel ideal geometry located in the middle of the base on the longitudinal axis of symmetry of the machine and the plane of rotation of which coincides with the instantaneous velocity vector of a given t USEC machine goggles, measuring the current angular velocity of the traction electric motor (TED) of each wheel, adjusting the angular speeds of all wheels so that they are equal to the USEC setting adjusted for the coefficient of correction of the angular velocities of the TED, depending on the angle of rotation of the steering wheel and the position of the steering pole setter, moreover, when the real value of the angular velocity of any wheel goes beyond the upper tolerance limit, the electric power supplied to the TED of the wheel before entering the permissible corridor is reduced, and when leaving The increase in the angular velocity of any wheel beyond the lower tolerance limit increases the sum of the electric power wheels to the TED before entering the permissible corridor. 2. The method according to claim 1, characterized in that the correction of the angular speeds of rotation of the traction electric motors of the wheels is carried out in a given period of time. 3. The method according to claim 1, characterized in that they provide several dependencies of the angular speed of rotation of the traction electric motor of the wheels on the position of the control element of the required speed of the wheeled vehicle, switching between which is carried out automatically according to a predetermined algorithm. 4. The method according to any one of claims 1 to 3, characterized in that the correction of the angular speeds of rotation of the traction motors of each wheel during wheel slip is carried out in the direction of decreasing the angular velocity until the cessation of slipping, using the ratio of the longitudinal acceleration of the wheel vehicle body to angular acceleration of each of the wheels.

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