AT524327A4 - Method of controlling an electrified steering and propulsion system - Google Patents

Abstract

The invention relates to a method for controlling an electrified steering and drive system (18) for a vehicle with two lanes and wheel side steering, which has drive elements (3, 4) for driving chains or for wheels, a transfer gear (9), two drive shafts (1, 2 ) and three electric machines (7, 8, 11), two of the three electric machines, in particular the first electric machine (7) and the second electric machine (8), being speed-controlled as a function of a steering request, so that a speed at the remaining, in particular the third electrical machine (11), where the remaining, in particular the third, electrical machine (11) is torque-controlled in order to achieve a specified power and/or load distribution between the two electrical machines, in particular the first electrical machine (7) and the second electrical machine (8) to set.

Description

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Method of controlling an electrified steering and propulsion system

The invention relates to a method for controlling an electrified steering and drive system for a vehicle with two tracks and wheel side steering, which has drive elements for track chains or for wheels, a transfer gear, and two drive shafts, a first drive shaft having a drive element of one track and one first electric machine is or can be connected in a torque-transmitting manner and a second drive shaft is or can be connected in a torque-transmitting manner to a drive element of the other track and a second electric machine, and wherein both drive shafts are connected in a torque-transmitting manner to the transfer gear, and wherein the transfer gear has two planetary gears, each with the elements sun gear, Has planet carrier and ring gear, wherein two identical first elements of the two planetary gears are each connected to transmit torque with one of the two drive shafts, with two identical second elements of the two plans Etentrieb are rotatably connected to each other, and wherein a third element of a planetary gear with a third electric machine is torque-transmitting connected and an equal third element of the other planetary gear with the third electric machine is torque-transmitting connected or is fixed to the housing.

Sidesteered vehicles corner by propelling one drive side at a different speed than the other drive side. For cornering, a drive device therefore drives the drive chain on the outside of the curve at a higher speed than the chain on the inside of the curve and thus also takes on the steering function of the vehicle in addition to the drive task. In order to turn such a vehicle on the spot, the tracks of the two vehicles are generally driven in opposite directions.

Such a type of steering and drive system is used in particular in vehicles in which an Ackermann steering is not possible. These are in particular tracked vehicles such as excavators or snow vehicles, but also wheel-driven vehicles

witnesses, such as wheeled armor.

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The document WO 2005/054041 discloses an electric steering and drive system for a vehicle with side wheel steering with drive elements for track chains or for wheels with two drive shafts, the first end of which is connected to the drive element of each side of the vehicle and the second end is connected to a differential gear arrangement and at least one traction motor, which is connected to at least one of the two drive shafts, and an electric steering drive, which is drivingly connected to the differential gear arrangement, characterized in that the traction motors and steering drives consist of at least two energy

sources can be supplied with electricity.

Document EP 1 506 905 A1 discloses a drive configuration for a skid steered vehicle, comprising:

a pair of drive motors,

a pair of drive members for engagement with a pair of tracks or wheels of such vehicle,

a controlled differential comprising: a pair of epicyclic gear systems each having a sun gear, planet gears carried by a planet carrier, and a ring gear, the planet carriers being interconnected by a shaft passing through the sun gears such that the planet carriers

rotate together, and

a steering motor coupled so that relative rotation between sun gears is in opposite directions, each drive motor being coupled between a respective drive member and a respective ring gear.

The steering motor, acting on the controlled differential, controls the relative speed of the two drive motors and hence the relative speed of the two tracks or wheels, and in this way effects a steering function. The motor shafts act as a drive cross shaft and transmit a regenerative steering force. This means that when braking, the braking force is transferred from the inner chain to the outer chain.

will wear.

It is an object of the invention to provide an improved method of controlling an electric steering and propulsion system for a dual track wheel side steering vehicle

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to provide. In particular, it is an object of the invention to provide an improved load

to achieve distribution between electric machines of the drive system.

This object is solved by the teaching of the independent patent claims. Advantageous developments are claimed in the dependent claims.

A first aspect of the invention relates to a method for controlling an electric steering and drive system for a vehicle with two tracks and wheel side steering, which has drive elements for track chains or for wheels, a transfer gear, and two drive shafts, a first drive shaft having a drive element of one track and a first electric machine is or can be connected in a torque-transmitting manner and a second drive shaft is or can be connected in a torque-transmitting manner to a drive element of the other track and a second electric machine, and both drive shafts are connected to the transfer gear in a torque-transmitting manner, and the transfer gear, in particular mirror-symmetrically arranged, planetary gear with each having the elements sun gear, planet carrier, which carries the planet gears, and ring gear, with two identical first elements of the two planetary gears each rotating with one of the two drive shafts are connected in a torque-transmitting manner, with two identical second elements of the two planetary gears being connected to one another in a torque-proof manner, and with a third element of one planetary gear being connected to a third electric machine in a torque-transmitting manner and an identical third element of the other planetary gear being connected to the third electric machine in a torque-transmitting manner or being fixed to the housing , wherein two of the three electric machines, in particular the first electric machine and the second electric machine, are speed-controlled as a function of a steering request, so that a speed of the remaining electric machine, in particular the third electric machine, is also fixed, the remaining electric machine, in particular the third electric machine, being torque-controlled in order to a predetermined power and / or load distribution between the two electric machines, in particular

those of the first electric machine and the second electric machine.

Preferably, the third element of the other planetary gear is torque-transmitting with the third electric machine with the opposite direction of action compared to

connected to the further third element.

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A second aspect of the invention relates to a system for controlling an electric steering and drive system for a vehicle with two lanes and wheel side steering, which has drive elements for track chains or for wheels, a transfer gear, and two drive shafts, a first drive shaft having a drive element of one track of a first electric machine is or can be connected in a torque-transmitting manner and a second drive shaft is or can be connected in a torque-transmitting manner to a drive element of the other track and a second electric machine, and both drive shafts are connected to the transfer gear in a torque-transmitting manner, and the transfer gear has two planetary gears, in particular the mirror-symmetrically arranged planetary gear each with the elements sun gear, planetary gear carrier has a ring gear, with two identical first elements of the two planetary gears each connected to one of the two drive shafts in a torque-transmitting manner are, wherein two identical second elements of the two planetary gears are connected to one another in a torque-proof manner, and wherein a third element of one planetary gear is connected to a third electric machine in a torque-transmitting manner and an identical third element of the other planetary gear is connected to a third electric machine in a torque-transmitting manner or is fixed to the housing, wherein the system has control means which are set up so that two of the three electric machines, in particular the first electric machine and the second electric machine, are speed-controlled as a function of a steering request, so that a speed is also fixed on the remaining, in particular the third electric machine, with the remaining, in particular Third, the electric machine is torque-controlled in order to achieve a predetermined power and/or load distribution between the two electric machines, in particular the first electric machine and the second

electric machine to set.

A third aspect of the invention relates to an electric steering and propulsion system for a vehicle with two lanes and wheel side steering with a system for controlling an electric

mechanical steering and drive system for a vehicle.

Speed-controlled within the meaning of the invention means that a controlled variable, i. H. the variable that is adjusted as the output variable of the respective electric machine is a speed. An input variable or setting variable, i. H. a variable, by means of which the respective electric machine is controlled, can be both a target value for the speed

as well as a target value for a torque.

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Torque controlled in the context of the invention means that the controlled variable, i. H. the variable that is adjusted as the output variable of the respective electric machine is a torque. An input variable or setting variable, with which the respective electric machine is controlled, can also be a target value for a speed or a target value for a torque.

Torque-transmitting connected within the meaning of the invention means preferably rotationally fixed and/or power-conserving connected.

A semi-rigid coupling according to the invention is preferably used to connect two axles or shafts that are not perfectly aligned. Such a coupling is preferably free of play in the direction of rotation, but compensates for a shaft misalignment.

The invention is based on the approach of realizing the steering function of the electrical steering and drive system via two of the three electrical machines, in particular the first and the second electrical machine, i.e. those electrical machines which are assigned to the drive shafts. For this purpose, the two electric machines are speed-controlled.

The remaining, in particular third, electric machine, however, which acts on the transfer gear and is generally used in systems of the prior art as a so-called steering motor to adjust the speed differences between a first drive shaft and a second drive shaft, is used in the operating method according to the invention and the invention Control system preferably not for controlling the speeds of the first drive shaft and the second drive shaft for

the steering function is used.

Rather, the speed that occurs at the remaining, in particular the third, electric machine based on speed values at the first drive shaft and the second drive shaft is treated as a predetermined boundary condition. The remaining, in particular third, electric machine is, in contrast to the prior art, in particular exclusively, torque-controlled, i.e. it is controlled in such a way that a specific support torque or no support torque is provided by it. This allows a defined power distribution or a defined load distribution between the two electric machines, in particular the first electric machine and the

second electric machine, and preferably also the remaining one, in particular

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third, electric machine to be adjusted. When cornering, the third electric machine can also contribute to power distribution or load distribution.

seriously

The method according to the invention and the control system can be used, for example, to relieve an electric machine on the outside of a bend, which has to generate more power than an electric machine on the inside of a bend. This is achieved by providing a support torque through the third electric machine. In this way it can be avoided that the electric machine on the inside of the curve has to be operated in a generator mode in order to reduce a braking power of the drive element on the inside of the curve. This braking power can be transported via the transfer gear and used on the drive element on the outside of the curve. This relieves the load on the electric machine on the outside of the curve. In addition, by providing a higher support torque through the third electric machine, such a large power flow can be realized via the transfer gear that the machine on the inside of the curve, even when braking power is applied to the drive element on the inside of the curve, has to apply additional power, which is used on the drive element on the outside of the curve and with which the

machine on the outside of the curve is relieved even more.

The two planetary gears are preferably asymmetrical, i.e. the third input of the transfer gear — in addition to the two inputs to which the two input shafts are each connected in a torque-transmitting manner — only acts on one element of one of the two planetary gears, whereas the same element of the other planetary gear is fixed to the housing is. In comparison to an arrangement in which the electric machine drives the two identical elements in opposite directions, as is the case in the prior art mentioned at the outset, a doubling of the speed at the third input can be achieved. A third electric machine can thus be connected to this input, the nominal operating range of which in relation to the speed is approximately twice as high as without the arrangement according to the invention. Another advantage of the element fixed to the housing, i.e. an asymmetrical arrangement in relation to the two planetary gears of the transfer gear, is that the steering and drive system is therefore less susceptible to tolerances and easier to store. In particular, this element acts as a fixed point fixed to the housing.

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In an advantageous embodiment of the method, the power and/or load distribution is specified in such a way as to optimize the efficiency of the electric steering and drive system and/or to achieve thermal distribution between at least the first electric machine and the second electric machine, in particular between all of them regulate three electric machines and/or to relieve the first electric machine or the second electric machine. The first electric machine and the second electric machine, for example, are operated at preferred operating points by controlling or regulating the steering and drive system under the specification of boundary conditions in relation to these criteria. Furthermore, overheating of one of the machines can be prevented by means of thermal management between the electric machines. Due to the possibility of relieving one of the electric machines by means of another, all electric machines and their power electronics can be designed with a lower maximum power. This saves costs, weight and valuable installation space in the vehicle.

In a further advantageous embodiment of the method, the third electric machine is operated without a load when the specified power and/or load distribution does not provide for a power flow between the first drive shaft and the second drive shaft, and the third electric machine is operated in such a way that it generates a support torque provides when the predetermined power and / or load distribution provides a power flow between the first drive shaft and the second drive shaft. These two operating strategies for the steering and drive system can, depending on the state of the electric machines and the specified boundary conditions, ensure a balanced power and/or load distribution while the vehicle is in motion, as well as a different power and/or load distribution between the first electric machine and the second electric machine can be achieved, for example, in order to

thermally relieve machines. .

In a further advantageous embodiment of the method, an effective direction of the support torque depends on a predetermined direction of a power flow between the first drive shaft and the second drive shaft. Different power and/or load distributions can therefore be implemented quickly by setting a support torque by the third electric machine. The direction of the power flow depends on the effective direction of the support torque and the speed (power = speed x torque).

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The third machine determines the torque based on the speeds and thus regulates the power flow. For example, at reverse speeds (driving backwards) the torque must also reverse in order to get power flow in the same direction as when driving forwards. The direction of the power flow is determined by the effective direction of the support torque of the third electric machine. More preferably, the speeds of the first drive shaft and the second drive shaft are set exclusively via the speeds of the first and second electric machines.

In a further advantageous embodiment of the method, the third electric machine is operated without load if the first electric machine and the second electric machine are controlled in such a way that the drive shafts rotate at the same speed. In this case, the power required at the respective drive element must be provided directly by the corresponding electric machine. With the same power requirement, this leads to the same power distribution on the first and second electric machines. This operating strategy for the steering and drive system makes it possible to achieve a balanced power and/or load distribution between the first electric machine and the second electric machine while driving straight ahead with the same power demand on the drive elements of the vehicle.

In a further advantageous embodiment of the method, the third electric machine is operated in such a way that it provides a support torque when the first electric machine and the second electric machine are controlled in such a way that the drive shafts rotate at the same speed and there is an uneven power requirement at the Drive elements is specified. A desired power flow between the two drive shafts via the transfer gear is set by the support torque, and a desired, preferably uniform, power distribution between the first and the second electric machine is realized. This operating strategy for the steering and drive system enables a uniform power and/or load distribution between the first electric machine and the second electric machine while the vehicle is driving straight ahead when the power demand on the drive elements is unequal

be reached.

In a further advantageous embodiment of the method, the third electric machine is operated without load if the first electric machine and the second electric machine are controlled in such a way that the drive shafts rotate at different speeds

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rotate and no power flow between the first drive shaft and the second drive shaft is specified. As a result of this operating strategy for the steering and drive system, an uneven power and/or load distribution between the first electric machine and the second electric machine can occur when the vehicle is cornering.

seem to be achieved.

In a further advantageous embodiment of the method, the third electric machine is operated in such a way that it provides a support torque when the first electric machine and the second electric machine are controlled in such a way that the drive shafts have different speeds and a power flow between the first Drive shaft and the second drive shaft is specified, in particular from that drive shaft, which rotates at a lower speed, to that drive shaft, which rotates at a higher speed. Since the third electric machine has a speed in this case, it also brings power into the system and contributes to the power balance. This operating strategy for the steering and drive system can be used to balance the power and/or load distribution between all three electric machines while the vehicle is cornering

The third electric machine is operated in such a way that it provides power itself in order to set a power distribution that is not necessarily uniform between the first electric machine, the second electric machine and the third electric machine. With this operating strategy, the electric machines can operate at a preferred operating point, the efficiency of the electric steering and drive system can be optimized and/or a desired thermal distribution can be adjusted and/or the first or second electric machine can be relieved in a targeted manner.

In a further advantageous refinement of the method, a power contribution from the third electric machine is selected in such a way that a uniform power and/or load distribution is established between the first electric machine and the second electric machine. As a result, all electrical machines can be involved in the power and/or load distribution.

In a further advantageous embodiment of the method, a power contribution of the third electric machine is selected in such a way that none of the three electric machines

because their maximum possible torque and/or their maximum possible power

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exceeds. This can prevent damage to the individual electric machines

will.

In a further advantageous embodiment of the method, a power contribution of the third electric machine is selected in such a way that, when one of the two drive shafts of the vehicle is operated in braking mode, the third machine is operated in such a way that the torque generated by it depends on the amount and corresponds in terms of effective direction to a braking torque on this drive shaft. As a result, a recuperation operation of the electric motor, which transmits torque directly with this drive shaft, can

machine are avoided.

In a further advantageous embodiment of the method, the first elements are the planetary carriers and the second elements are the ring gears, so that the two planetary gear carriers of the two planetary gears are each connected to the drive shaft of one of the two tracks in a torque-transmitting manner and the two ring gears of the two planetary gears are connected to one another in a torque-proof manner . As a result, a particularly compact design and, at the same time, a high transmission ratio of the transfer gear can be achieved.

In a further advantageous embodiment of the steering and drive system, the electric machines have sensors with which they can be thermally monitored. Such sensors can preferably be used to regulate the electric machines in such a way that a thermal load on the electric machines is defined.

can be distributed freely.

In a further advantageous embodiment of the steering and drive system, the control means are set up to determine the power consumed by the electric machines. In particular, the control means for voltage and current

determine the flow of at least one of the electric machines.

The advantages mentioned above and further features of the first aspect of the invention apply correspondingly to the further aspects of the invention and vice versa.

Further features and advantages are described below with reference to the figures. It shows at least partially schematically:

FIG. 1 shows a vehicle with two lanes and lateral wheel steering;

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FIG. 2 shows an exemplary embodiment of a control scheme for an electric steering and drive system for a vehicle with two lanes and side wheel steering;

Figure 3 shows a first embodiment of an electric steering and drive system

for a vehicle with two lanes and wheel side steering;

Figure 4 shows a second embodiment of an electric steering and drive system

for a vehicle with two lanes; and

Figure 5 shows a third embodiment of an electric steering and drive system

for a vehicle with two lanes;

Figure 1 shows an excavator 31. Such an excavator 31 generally has two tracks and is driven by means of chains which run on drive elements.

With such a chain drive, the steering is accomplished by means of a so-called lateral wheel steering. The two chains rotate at different speeds and possibly even in different directions. The drive elements 3 are generally part of an electric steering and drive system.

It goes without saying for a person skilled in the art that the steering and drive systems described below are also fundamentally suitable for wheel-driven vehicles which do not have an Ackermann steering. In addition, they are not only suitable for excavators, but also for other vehicles such as snowmobiles,

Zer, etc.

FIG. 2 shows an exemplary embodiment of a control scheme for such an electric steering and drive system 18 for a vehicle with two lanes and side-wheel steering, which is illustrated in detailed exemplary embodiments in FIGS.

To simplify the illustration, only the devices that are generally most necessary for the function of the steering and drive system are shown in FIG. Detailed embodiments are described in relation to Figures 3 to 5 below.

The devices shown in Figure 2 are a first drive member 3 which would be associated with one lane in a dual carriage vehicle, a second drive member 4 which would be associated with the other lane in a dual carriage vehicle, a first

Drive shaft 1, which transmits torque to the first drive element 3

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is connected, a second drive shaft 2, which is connected to the second drive element 4 in a torque-transmitting manner, the two drive shafts 1, 2 each being connected to a first input and a second input of the transfer gear 9 and also being connected to one another via the transfer gear 9 if the third electric machine 11 provides a support torque, a first drive machine 7 and a second drive machine 8, which are each connected to the first drive shaft 1 and the second drive shaft 2 in a torque-transmitting manner, and a third electric machine 11, which is connected to a third input of the transfer gear 9 is torque-transmitting connected.

Furthermore, sensors 26, 27, 28 are shown in FIG. 2, which can determine actual values on the electric machines by measuring, in particular actual values of the variables being controlled in each case. In addition, the current intensity and voltage at the electrical machines 7, 8, 11 can preferably be detected in order to determine component performances for power distribution. Additional measuring equipment can be available for this purpose — or the sizes of characteristic curves of the components can be deduced. Furthermore, thermal sensors can be provided on or in the electrical machines 7, 8, 11 for thermal control.

be at hand.

Both the sensors 26, 27, 28 and other measuring means and sensors as well as the electrical machines 7, 8, 11 are signal-connected to a controller which has control means 25, as indicated by the dashed lines.

A means within the meaning of the invention can be designed in terms of hardware and/or software and, in particular, a data or have signal-connected, in particular digital, processing units, in particular microprocessor units (CPU) and/or one or more programs or program modules. The CPU can be designed to process commands that are implemented as a program stored in a memory system, to detect input signals from a data bus and/or to emit output signals to a data bus. A storage system can have one or more, in particular different, storage media, in particular optical, magnetic, solid-state and/or other non-volatile media. The program may be of such a nature that it embodies or is capable of performing the methods described herein, such that the CPU performs the steps of such

procedure can perform.

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Furthermore, the control means 25 can control components of a steering and drive system 18 . In the following, however, a control, in particular regulation, of the electric machines 7, 8, 11 for steering a vehicle and for power and/or load distribution between the electric machines 7, 8, 11 is mainly described with reference to FIG. 2:

The first electric machine 7 and the second electric machine 8 are each speed-controlled, i. H. a target value nsaı_ 1 of the rotational speed is specified for the first electric machine 7 and a target value nsoı_2 is also specified for the second electric machine 8 . These target values nsoı_1, Nsol_2 are each specified on the basis of a steering request for the vehicle. If the first drive element 3 is part of the left-hand lane in the direction of travel of the vehicle and the second drive element 4 is part of the right-hand lane of the vehicle in the direction of travel, the setpoint value nsoln 1 of the first electric machine 7 is reduced and the setpoint value is reduced to execute a left turn nsoı_2 of the second electric machine 8 increased - at a constant speed of the vehicle. For driving straight ahead, the first electric machine 7 and the second electric machine 8 essentially rotate at the same speed. For this reason, setpoint values Nsoll_1, Nsol_2, which are the same, are specified for straight-ahead driving. Instead of the setpoints nso_1, Nsol_2 for the speed, setpoints Msonn, Msoız for the torque to be generated can also be specified as setting variables. However, when controlling the torque to be generated under real conditions, it should be noted that there are tolerances in the internal friction of the chain links, which can be increased, for example, by dirt on one side or wear (the service life of a chain is typically less than 1000 km). This can result in different drive torque requirements on the right and left even when driving straight ahead. It is essential that the actual values of the controlled variable, namely the speed nact 1, Nact 2, at least essentially

accept the value of the setpoints nsol_1, Nsoll_2.

A speed is therefore set on the first drive shaft 1 and the second drive shaft 2 by the first electric machine 7 and the second electric machine 8 , so that the speed is specified by the control means 25 at two of the three inputs of the transfer gear 9 .

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The speed at the third input of the transfer gear 9, which is connected in a torque-transmitting manner to the third electric machine 11, is thereby fixed, and thus also the speed of a shaft of the third electric machine 11.

The third electric machine 11 is therefore controlled by specifying a setpoint value Msoı_3 for the torque provided by this electric machine 11 at the speed present at the third input to the transfer gear 9 . Here too, instead of the setpoint value Msoaı_3 for the torque, a setpoint value nsou_3 for the speed to be provided can be specified as the setting variable. It is essential that the control or regulation parameter Mist 3 at least essentially assumes the value of the setpoint value Msoı_3.

If the first drive shaft 1 rotates at the same speed as the second drive shaft 2, the speed at the third input of the transfer gear 9 and thus at the third electric machine 11 is equal to 0. If the first drive shaft 1 rotates at a speed which is different from the Speed of the second drive shaft 2, z. B. during cornering, a defined speed occurs at the third input of the transfer gear 9, and thus at the third electric machine 11. This speed is determined by the difference in the speeds between the first drive shaft 1 and the second drive shaft 2, since the third input of the transfer gear 9 represents the only degree of freedom of the transfer gear 9 which compensates for this speed difference

can.

Irrespective of the rotational speed set at the third input of the transfer gear 9, a power flow from the first drive shaft 1 to the second drive shaft 2 or vice versa can be set by the third electric machine 11 providing a support torque at the third input. Such a power flow can be used to regulate the power and/or load distribution between the first electric machine 7 and the second electric machine 8 . In this way, in particular, the efficiency of the electric steering and drive system 18 can be optimized, for example by the electric machines 7, 8, 11 being operated at optimized operating points. In addition, peak loads on the first electric machine 7 or on the second electric machine 8 can be compensated by the other existing electric machines, so that each of the electric machines 7, 8, 11 can only be dimensioned smaller. Similarly, a distribution of thermal energy

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possible between the electric machines. In addition, the first electric machine 7 or the second electric machine 8 can be relieved in a targeted manner.

Depending on the direction in which the support torque acts on the third input of the transfer gear 9, a power flow occurs from the first drive shaft 1 to the second drive shaft 2 or vice versa. From there, the power flow is transmitted via the respective torque-transmitting connection to the second drive element 4 or, for example, to the second electric machine 8 during braking maneuvers of the vehicle or, conversely, from the drive shaft 1 to the first drive element 3 or to the first electric machine 7 .

If the first drive shaft 1 and the second drive shaft 2 rotate at different speeds, for example while a vehicle is cornering, a defined speed is set at the third input of the transfer gear 9, as described above.

In this case, by providing a support torque, not only can a power transfer be set between the two vehicle sides or drive shafts 1, 2, but by providing power at the third input of the transfer gear 9, additional power can be fed into the steering and drive system 18 are introduced or, in particular in a recuperation operation of the third electric machine 11, are removed from this. Both the support torque and the provision of power at the third input of the transfer gear 9 can be accomplished by specifying the setpoint value Msoıu_3 of the torque for the controlled variable Mist 3 of the third electric machine 11 .

By providing power through the third electric machine 11 and the associated additional power flow from or to the third electric machine 11, a power or load (re)distribution between the three electric machines 7, 8, 11 can be undertaken. Due to the fact that the electric machine 11 can only contribute power at a predetermined speed at the third input of the transfer gear 9, the power balance is reduced by the support torque of the electric machine 11 at the same speeds of the first and second drive shafts 1, 2, i.e. when driving straight ahead, on the electric machines 7 and 8

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Sensors 26, 27, 28 are preferably used to measure actual values on the shafts of electric machines 7, 8, 11, which are also transmitted to control means 25 via signal lines. Furthermore, currents and voltage drops as well as actual temperatures are preferably measured in the electric machines 7, 8, 11 and also transmitted to the control means 25 via the signal line. These actual values, actual 1, actual 2, actual 3, are preferably used to regulate the electric machines 7, 8, 11. Below are some examples of control states of the electric steering and drive system:

In a first example, a uniform power and/or load distribution between the first electric machine 7 and the second electric machine 8 is to be achieved when driving straight ahead with the same power demand on the drive elements 3 , 4 . In this case, the first electric machine 7 and the second electric machine 8 are operated in such a way that the first drive shaft 1 and the second drive shaft 2 have the same speed and the third electric machine is operated without a load.

In a second example, when driving straight ahead, power should flow from the first electric machine 7 to the opposite drive element 4 . For example, this makes sense when the power requirements for the drive elements 3, 4 are unequal. In this case, too, the first electric machine 7 and the second electric machine 8 are operated in such a way that the first drive shaft 1 and the second drive shaft 2 rotate at the same speed. In addition, the third electric machine 11 provides a support torque at the third input of the transfer gear 9 in such a way that the power of the first electric machine 7 can be increased and the power of the second electric machine 8 can be reduced to the same extent without this entails a change in the speeds on both drive shafts.

In a third example, a power flow is to be formed from the second electric machine 8 to the opposite drive element 3 while cornering. This is the case, for example, in a right-hand curve, where the power demand on the drive element 3 on the outside of the curve increases and the drive element 4 on the inside of the curve has to be braked. If it is a right-hand curve, the second electric machine 8 is operated in such a way that the second drive shaft 2 has a lower Speed than the first drive shaft 1 has. At the same time, a support torque is provided by the third electric machine 11 at the third input of the transfer gear 9 in such a way that it

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braking on drive shaft 2 and accelerating on drive shaft 1, thus enabling a power flow from the drive shaft 2 on the inside of the curve to the drive shaft 1 on the outside of the curve. By selecting the appropriate level of torque on the third electric machine 11, the braking power can be transferred from the drive element 4 to the drive element 3 and used there as additional drive power for the first electric machine 7, and power can also be transferred from the electric machine 8 on the inside of the curve via the transfer gear 9 to the Drive element 3 are transmitted. All of this, together with the fact that the third electric machine 11 now brings additional power into the system, leads to a reduction in the power demand on the first electric machine 7 on the outside of the curve and thus to its relief. In addition, the second electric machine 8 does not have to be operated in recuperation mode, but can be active

contribute to the mechanical power balance.

The power distribution between the second electric machine 8 and the first electric machine 7 is preferably set in such a way that both electric machines 7, 8 have a uniform power and/or load requirement. More preferably, for example in the right turn just described, the power at the second electric machine 8 and/or at the third electric machine 11 is increased until one or both powers reach the power value that must be provided by the first electric machine 7 . For left-hand bends, the power or power setting is increased via the electric machines 7 and 11. The three electric machines 7, 8, 11 are preferably operated in such a way that at least the two highest power requirements for the three electric machines are at a comparable level, so that two Electric machines have to generate the same power value. More preferably, the three electric machines 7, 8, 11 are operated in such a way that none of the electric machines 7, 8, 11 exceed their maximum possible torque and/or their maximum possible power.

In a fourth example, when cornering, one of the lanes of the vehicle is operated in the braking mode, in the present example the right lane. In this case, the corresponding speeds on the first drive shaft 1 and on the second drive shaft 2 are set by the first and second electric machines 7, 8 and the third electric machine 11 is operated in such a way that the rotational speed applied by this

moment in terms of amount and effect, at least in a right-hand bend

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braking torque to be provided on the drive element 4 and thus the second drive shaft 2 or, in the case of a left turn, a braking torque to be provided on the drive element

ment 3 and thus the first drive shaft 1 corresponds.

FIG. 3 shows a first exemplary embodiment of an electric steering and drive system 18 for a vehicle with two lanes and side-wheel steering.

The electric steering and drive system shown in FIG. 3 couples three electric machines 7, 8, 11 via a transfer gear 9, which has two planetary gears connected to one another.

Both planetary gears each have a sun gear 14, 15, a ring gear 16, 17 and a planet carrier 12, 13, which carries the planet gears. The two planetary gears are connected via the two ring gears 16, 17 in a torque-transmitting manner. For this purpose, the ring gears 16, 17 are connected to one another in a rotationally fixed manner or are designed as a single ring gear 16, 17. The planetary carrier 12 of the planetary gear shown on the left in FIG. 3 is non-rotatably connected to a first drive shaft 1 ; The first drive shaft 1 can also be coupled in a torque-transmitting manner to a first electric machine 7 of the three electric machines by means of a transmission 5 . In particular, this is a speed-reducing transmission from the first electric machine 7 to the first drive shaft 1, i.e. a transmission which reduces a speed provided by the first electric machine 7 up to the first drive shaft 1 and correspondingly increases the torque.

This first transmission 5 preferably has two gears. The two respective translations are shown in Fig. 3 by a border with different dashed lines. The two gears are preferably shifted via a clutch 19. In a corresponding manner, the second electric motor 8 is connected to the second drive shaft 2 via the second transmission 6, which is also preferably speed-reducing, in a torque-transmitting manner. This second gear 6 preferably also has two gears, more preferably with the same gear ratio as the gears of the first gear 5. More preferably, these two gears are also shifted with a clutch 20 each.

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The third electric machine 11 is connected via a third gear 10 to a sun gear 14 of the transfer gear 9 in a torque-transmitting manner. This third transmission 10 is preferably also a transmission that reduces the speed from the electric machine 11 to the sun wheel 14 and correspondingly increases the torque provided. In Fig. 3, this sun gear, which is torque-transmittingly connected to the third electric machine 11, is the left-hand sun gear 14, whereas the right-hand sun gear, i. H. the sun gear 15 of the right planetary gear, fixed to the housing, d. H. is rotatably mounted. The third transmission 10 advantageously has a separating element, not shown, through which the connection between the third electric machine 11 and the transfer transmission 9 is separated. This is advantageous when, due to a fault, the third electric machine 11 can no longer be turned and the vehicle drive would therefore be blocked. The third electric machine 11 can thus be uncoupled and the first and second electric machines 7, 8 drive the drive shafts 1, 2.

The first drive shaft 1 is preferably connected in a torque-transmitting manner to its first drive element 3 via a first further planetary gear 21 . Furthermore, a semi-rigid coupling 23 is preferably interposed in this connection.

More preferably, the first drive shaft 1 is locked by means of a first brake 29

brakes.

Correspondingly, the second drive shaft 2 is connected in a torque-transmitting manner to the second drive element 4 preferably via a second further planetary gear 22 and likewise more preferably via a second semi-rigid clutch 24 . Also the

second drive shaft 2 can be braked by means of a second brake 30 .

The operation of the three electric machines 7, 8, 11 is preferably monitored by means of suitable sensors. In particular, the first electric machine 7 is monitored by a first speed sensor 27 , and the second electric machine 8 is monitored by a second speed sensor 28 . These speed sensors 27, 28 determine the actual values of the speed nact 1, Nact 2 present on the shafts of the electric machine 7, 8. A third sensor 26 preferably monitors the third electric machine 11 and determines an actual torque Mist 3 present on its shaft The respective actual values are provided to a control means 25, which is designed in particular as a data processing device, as indicated by the dotted lines in Fig. 3 and with reference to Fig. 2

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was described. Furthermore, the control means 25 are signal-connected to the three electric machines 7, 8, 11. On the one hand, they supply the control means with actual values for the current levels and voltage drops, as well as actual values for the temperatures of the electrical machines 7, 8, 11; For the three electric machines 7, 8, 11, a torque Msoı_ 1, Msol_2, Mol 3 or a speed nson 1, Nsoll_2, Nsoalt_3 are used as inputs.

manipulated variable possible.

The control means 25 are preferably also connected in a signal-transmitting manner to actuators of the other actuating elements of the steering and drive system 18 in order to control or regulate them, in particular to the clutches 19, 20 and the brakes 29, 30.

FIG. 4 shows a second exemplary embodiment of an electric steering and drive system 18 for a vehicle with two lanes and side wheel steering. This exemplary embodiment essentially corresponds to the first exemplary embodiment according to FIG. 3. Corresponding elements are identified in the same way.

In contrast to this, the third transmission 10 is formed by a pinion around bevel gears, the bevel pinion being driven by the shaft of the third electric machine 11 and the sun gears 14, 15 being actuated by the bevel gears 32, 33, in particular being non-rotatably connected to them. In this exemplary embodiment, the ring gears 16, 17 of the planetary gear 9 are also connected in a torque-proof manner to one of the first drive shaft 1 and the second drive shaft 2, and the planetary gears of the transfer gear 9 are coupled via the planet carriers 12, 13, with the two planet carriers 12, 13 being torque-proof are connected. Here, too, a separating element (not shown) can advantageously be provided between the third electric machine 11 and the transfer gear 9 .

FIG. 5 shows a third exemplary embodiment of an electric steering and drive system 18 for a vehicle with two lanes and wheel side steering. Corresponding elements are numbered the same as in Figs.

In contrast to the second exemplary embodiment according to FIG. 4, the third transmission 10 consists of two spur gears, which are arranged on the same shaft, which in turn is operated by the third electric machine 11. Again, in advantageous

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Way a not shown separating element between the third electric machine 11 and the transfer gear 9 may be provided.

One of the two spur gears on the shaft meshes with another spur gear, which is non-rotatably connected to the sun gear 14 of one of the two planetary gears of the transfer gear 19 . The second spur gear on the shaft in FIG.

In addition, it should be noted that the exemplary embodiments are only examples and are not intended to limit the scope, applications and structure in any way. Rather, the above description gives the person skilled in the art a guideline for the implementation of at least one exemplary embodiment, with various changes, in particular with regard to the function and arrangement of the described components, being able to be made without departing from the scope of protection as it results from the claims and these equivalent feature

combinations.

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Reference List

1 first driveshaft

2 second driveshaft

3 first drive element 4 second drive element 5 first gear

6 second gear

7 first electric machine

8 second electric machine 9 transfer gear

10 third gear

11 third electric machine

12, 13 planet carrier

14, 15 sun gear

16, 17 ring gear

18 steering and drive system

19 first clutch

20 second clutch

21 first additional planetary gear 22 second additional planetary gear 23 first semi-rigid clutch

24 second semi-rigid coupling

25 tax means

26 third sensor

27 first sensor

28 second sensor

29 first brake

30 second brake

31 vehicle

32, 33 bevel gear

15.12.2020

Claims (1)

15 20 25 30 PB33116AT 12/15/2020 -283- patent claims Method for controlling an electrified steering and drive system (18) for a vehicle with two lanes and wheel side steering, which drive elements (3, 4) for driving chains or for wheels, a transfer gear (9), and two drive shafts (1, 2) wherein a first drive shaft (1) is or can be connected in a torque-transmitting manner to a drive element (3) of one track and a first electric machine (7) and a second drive shaft (2) to a drive element (4) of the other track and a second electric machine (8) is or can be connected in a torque-transmitting manner, and wherein both drive shafts (1, 2) are connected in a torque-transmitting manner to the transfer gear (9), and wherein the transfer gear (9) has two planetary gears, in particular arranged mirror-symmetrically, each with the elements sun wheel, planet wheel carrier and Having ring gear, wherein two identical first elements (12, 13) of the two planetary gears each with one of the two Antriebswe llen (1, 2) are connected in a torque-transmitting manner, with two identical second elements (16, 17) of the two planetary gears being connected to one another in a torque-proof manner, and with a third element (14) of one planetary gear being connected with a third electric machine (11) in a torque-transmitting manner and an identical third element (15) of the other planetary gear is connected to the third electric machine (11) in a torque-transmitting manner or is fixed to the housing, with two of the three electric machines, in particular the first electric machine (7) and the second electric machine (8), being speed-controlled as a function of a steering request so that a speed of the remaining, in particular third, electric machine (11) is also fixed, with the remaining, in particular third, electric machine (11) being torque-controlled in order to achieve a predetermined power and/or load distribution between the two electric machines, in particular the first electric machine (7) and the second electric machine ine (8), a- to deliver. 2. The method of claim 1, wherein the power and / or load distribution in the Way is specified to an efficiency of the electric steering and 24/38 15 20 25 30 PB33116AT 12/15/2020 "24 - to optimize the drive system and/or to regulate a thermal distribution between the first electric machine (7), the second electric machine (8) and/or the third electric machine (11) and/or to one of the electric machines, in particular the first electric machine (7) or the second electric machine (8), too relieve. 3. The method according to claim 1 or 2, wherein the third electric machine (11) is unloaded is operated when the specified power and/or load distribution does not provide for a power flow between the first drive shaft (1) and the second drive shaft (2), and the third electric machine (11) is operated in such a way that it provides a support torque, if the specified power and/or load distribution provides for a power flow between the first drive shaft (1) and the second drive shaft (2). 4. The method according to claim 3, wherein an effective direction of the support moment of a predetermined direction of power flow between the first drive shaft (1) and the second drive shaft (2). 5. The method according to any one of the preceding claims, wherein the remaining in particular the third electric machine (11), without rotating, is operated without load if the two electric machines (7, 8), in particular the first electric machine (7) and the second electric machine (8), are controlled in such a way that the Drive shafts (1, 2) rotate at the same speed and there is no power and/or load redistribution between the two electric machines, in particular the first electric machine (7) and the second electric machine (8). 6. The method according to any one of the preceding claims, wherein the third electroma- machine (11) is operated in such a way that, without rotating, it provides a support torque when the first electric machine (7) and the second electric machine (8) are controlled in such a way that the drive shafts (1, 2) rotate at the same speed and one of the drive elements (3,4) independent 15 20 25 30 PB33116AT 12/15/2020 10 -25- Power and / or load distribution between the first electric machine (7) and the second electric machine (8) is specified. Method according to one of the preceding claims, wherein the remaining rotating, in particular third, electric machine (11) is operated without load when the two electric machines (7, 8), in particular the first electric machine (7) and the second electric machine (8), in be controlled in such a way that the drive shafts (1, 2) rotate at different speeds and no power flow between the first drive shaft (1) and the second drive shaft (2) is specified. Method according to one of the preceding claims, wherein the rotating, the remaining, in particular third, electric machine (11) is operated in such a way that it provides a support torque when the two electric machines (7, 8), in particular the first electric machine ( 7) and the second electric machine (8) are regulated in such a way that the drive shafts (1, 2) have different speeds and a power flow between the first drive shaft (1) and the second drive shaft (2) is specified, in particular from that Drive shaft, which rotates at a lower speed, to that drive shaft, which rotates at a higher speed. Method according to one of the preceding claims, wherein a support torque and / or a power contribution of the remaining, in particular third electric machine (11) is selected in such a way that a uniform power and / or load distribution between the two electric machines (7, 8), in particular the first electric machine (7) and the second electric machine (8). Method according to one of the preceding claims, wherein a support torque and / or a power contribution of the third electric machine (11) is selected in such a way that none of the three electric machines (7, 8 11) each have their maximum possible torque and / or their maximum possible power exceeds. 15 20 25 30 PB33116AT 12/15/2020 11. 12. 13. 14 -26- Method according to one of the preceding claims, wherein when one of the two drive shafts (1, 2) of the vehicle is operated in braking mode, the third machine (11) is operated in such a way that the torque applied by it in terms of amount and direction of action is at least one braking torque corresponds to this drive shaft (1, 2). Method according to one of the preceding claims, wherein the first elements are the planet carriers (12, 13), the second elements are the ring gears (16, 17) and the third elements are the sun gears (14, 15), so that the two planet gear carriers (12, 13) of the two planetary gears are each connected to the drive shaft (1, 2) of one of the two tracks in a torque-transmitting manner, with the two ring gears (16,17) of the two planetary gears being non-rotatably connected to one another and the sun gear (14) of one planetary gear being connected to the third Electric machine (11) is connected to transmit torque and the sun gear (15) of the other planetary gear is fixed to the housing. Method according to one of claims 1 to 11, wherein the first elements are the ring gears (16, 17), the second elements are the planet carriers (12, 13) and the third elements are the sun gears (14, 15), so that the two ring gears ( 16, 17) of the two planetary gears are each connected to the drive shaft (1, 2) of one of the two tracks in a torque-transmitting manner, with the two planet carriers (12, 13) of the two planetary gears being connected to one another in a torque-proof manner and the two sun gears (14, 15) of the both planetary gears are connected to the third electric machine (11) in a torque-transmitting manner. System for controlling an electrified steering and drive system (18) for a vehicle with two lanes and wheel side steering, which has drive elements (3, 4) for driving chains or for wheels, a transfer gear (9), and two drive shafts (1, 2), wherein a first drive shaft (1) is or can be connected in a torque-transmitting manner to a drive element (3) of one track and a first electric machine (7), and a second drive shaft (2) to a drive element (4) of the other track and a second electric machine (8 ) is connected or can be connected in a torque-transmitting manner, and wherein both drive shafts (1, 2) 27738 15 20 PB33116AT 12/15/2020 "27 - are connected to the transfer gear (9) in a torque-transmitting manner, and wherein the transfer gear (9) has two planetary gears, in particular arranged mirror-symmetrically, each with the elements sun gear, planet gear carrier and ring gear, with two identical first elements (12, 13) of the two planetary gears each with one of the two drive shafts (1, 2) are connected in a torque-transmitting manner, with two identical second elements (16, 17) of the two planetary gears being connected to one another in a torque-proof manner, and with a third element (14) of one planetary gear being connected to a third electric machine (11) in a torque-transmitting manner is connected and an identical third element (15) of the other planetary gear is connected to a third electric machine (11) in a torque-transmitting manner or is fixed to the housing, the system having control means which are set up to control two of the three electric machines, in particular the first electric machine (7) and the second electric machine (8), to operate with speed control as a function of a steering request, so that a speed is also fixed on the remaining, in particular third, electric machine (11), and to operate the remaining, in particular third, electric machine (11) with torque control in order to achieve a specified power and/or or load distribution between the two electric machines, in particular the first electric machine (7) and the second electric machine (8), and are preferably set up Carry out the method according to any one of claims 1 to 14. 15. Electric steering and propulsion system for a vehicle with two lanes and wheel side steering, comprising a system according to claim 14.