DRIVE CONTROL METHOD

Description

[0001] The present invention relates to a method for controlling the drive of actuators of at least one wheel of a vehicle. The invention also relates to a drive control system, a vehicle, a program element, and a computer-readable medium. State of the art

[0002] To control the drive of actuators of at least one wheel of a vehicle, a large number of subsystems are often used, whose consistent interaction can only be tested and / or optimized after the subsystems have been combined. This can, in at least some cases, involve considerable effort. It is therefore desirable to reduce the number of subsystems for drive control and combine the required functions into a few, ideally a single drive control system.

[0003] Document US 2003 / 0105573 A1 discloses a vehicle speed control system for a vehicle equipped with an engine and an automatic transmission. The vehicle control system includes a switch for reducing a set vehicle speed when the switch is turned on; and a controller connected to the switch. The controller controls the vehicle speed to the set vehicle speed by controlling a throttle of the engine and the automatic transmission. The controller maintains the gear ratio of the automatic transmission at the gear ratio set at the moment before the set vehicle speed is reduced by turning on the switch until the switch is turned off. Disclosure of the invention

[0004] The object of the invention is to provide a drive control system that consistently considers a multitude of relevant parameters. This object is achieved by the subject matter of the independent patent claims. Further developments of the invention emerge from the subclaims and the following description.

[0005] One aspect relates to a method for controlling the drive of actuators of at least one wheel of a vehicle, comprising the steps: detecting a desired acceleration; detecting a vehicle speed of the vehicle; detecting a wheel speed of the wheel; determining a state description of the wheel from a wheel speed and a wheel acceleration, wherein the state description comprises a static description that is a function of the wheel speed and the wheel acceleration; determining a first value of a wheel target acceleration from the state description, a slip of the wheel, and the desired acceleration, wherein the slip is a function of the wheel speed and the vehicle speed; determining a second value of the wheel target acceleration from the wheel speed, the wheel acceleration, and the slip, wherein the second value is a function of correction factors of at least one matrix;and determining a third value of the wheel target acceleration that controls the actuators of the at least one wheel, wherein the third value is a function of the first value and the second value. ;

[0006] The vehicle can be, for example, a land vehicle, in particular a passenger car, a van, a truck, a motorcycle or a special land-based vehicle. The vehicle can be an at least partially automated vehicle. The vehicle can have two, three, four or more wheels. A wheel can be understood to be a single wheel, a dual wheel - e.g. of a truck or motorcycle - and / or another type of multiple wheel. The actuators can comprise, for example, a powertrain and / or a brake. The powertrain can have an internal combustion engine and / or an electric motor. The powertrain can act on a single wheel or on multiple wheels, in particular on one axle. The brake can act on a single wheel or on multiple wheels.

[0007] The desired acceleration can be detected, for example, using an accelerator pedal, a joystick, an assistance system (e.g. cruise control, etc.) and / or another type of sensor. The vehicle speed v GND of the vehicle is the speed of the vehicle above the ground. The vehicle speed can be determined, for example, by averaging, voting, and / or other methods from the wheel speeds of at least two wheels, using acceleration sensors, positioning systems such as GPS (Global Positioning System), a combination of these methods, and / or other methods. The wheel speed of the wheel can be determined, for example, using one or more sensors on the wheel and / or an axle to which the wheel is directly connected. The wheel acceleration or wheel dynamics is the first or second derivative of the wheel speed with respect to time.The wheel acceleration and / or wheel dynamics can be calculated and / or provided directly by one or more sensors.

[0008] The wheel state description, based on the wheel speed and wheel acceleration, includes a static description as a function of the wheel speed and wheel acceleration. The function can comprise a logical combination of ranges of the wheel speed and wheel acceleration, for example, in the form "current wheel speed greater than desired wheel speed AND current wheel acceleration greater than desired wheel acceleration." The current wheel speed or current wheel acceleration can be determined, for example, from the wheel speed, and the desired wheel speed or desired wheel acceleration can be determined from the desired acceleration. The state description or function can optionally take wheel dynamics into account.

[0009] The drive control may include determining the target wheel acceleration, i.e., the acceleration (or derived variables such as torque) applied to the actuators. The target wheel acceleration may be determined in multiple stages and / or by a combination of multiple values.

[0010] The first value of the target wheel acceleration can comprise a qualitative value, for example, a value comprising a set of values ​​{acceleration, deceleration, holding}. The qualitative value can advantageously contribute to avoiding "gross" errors in determining the target wheel acceleration and can thus help prevent instabilities resulting from determining the target wheel acceleration. The slip s, as a function of the wheel speed v and the vehicle speed v GND , can be defined, for example, in percent and / or in m / s. The slip s can, for example, have been determined from a formula s = v GND - v.

[0011] The second value of the target wheel acceleration can comprise a quantitative value, for example, a value "plus 2 Nm," "minus 0.5 Nm." The second value, as a function of correction factors from at least one matrix, can, for example, directly adopt an element of the matrix, assign it a weighting and / or another function, and / or interpolate between two values ​​of the matrix. The matrix can be implemented as a single matrix or as a plurality of matrices. For example, each individual wheel can comprise a matrix with correction factors for the drivetrain and the brake, and / or for positive and negative acceleration, and / or additional matrices. The second value can, for example, have been determined experimentally, by means of simulation(s), by experts, by a neural network, and / or by means of other methods. The second value can be fixed for the duration of the vehicle's operation, or it can be variable, e.g.based on maintenance, a tire change, training of a neural network and / or other events or triggers.

[0012] The third value of the target wheel acceleration can be a function of the first value and the second value. In particular, the third value can be formed from the first value, the second value, and / or from further values ​​and / or information. The third value can be implemented as a single value and / or as a composite value—e.g., comprising one value each for the drivetrain and the brake.

[0013] This method advantageously takes a large number of relevant parameters of a drive control system into account in a consistent manner. This can improve the testing and / or optimization of the drive control system in several aspects, e.g. with regard to test time, probability of errors, stability, ease of maintenance and / or other aspects. It is particularly advantageous that potential instabilities can be reduced or even avoided right from the start. Furthermore, this method can lay a foundation for optimizing the drive control system during the operating life of the vehicle, for example through advances in simulations and / or learning machines such as neural networks. It can be particularly advantageous that, in many embodiments of this method, changes can only affect the matrix.

[0014] In some embodiments, the wheel state description further includes a dynamic description, which is a function of the wheel acceleration and wheel dynamics. A dynamic description is understood to be the description of a static current state in combination with a defined historical time window—e.g., greater than 0.5 ms, greater than 1 ms, greater than 2 ms, in many cases a multiple of the computing time or cycle time. Possible description forms for the dynamic description can include, for example: The wheel's state description has not exceeded the currently valid state boundary range in the defined past time window, e.g., dependent on the current state description ("Steady in State"). The wheel's state description has continuously exceeded state boundary ranges in a positive direction in the defined past time window and also shows a positive trend in the current state description ("State ascending & Signal increasing"). The wheel's state description has continuously exceeded state boundary ranges in a positive direction in the defined past time window, but shows a trend in the opposite direction in the current state description ("State ascending & Signal decreasing").The state description of the wheel has continuously exceeded state limit ranges in a negative direction in the defined past time window and also shows a trend in a negative direction in the current state description ("State declined & Signal decreasing").

[0015] In some embodiments, the wheel state description further includes a predictive description that is a function of the wheel dynamics. Wheel prediction is understood to be the description of the static current state in combination with a defined prediction time window (future). Possible description forms for wheel predictions or the predictive description can include, for example: The wheel's condition description will likely hit the target zone within the defined prediction time window and the currently effective dynamics ("TargetZone hit"). The wheel's condition description will likely exceed / overshoot the target zone within the defined prediction time window and the currently effective dynamics ("TargetZone crossed"). The wheel's condition description will not hit the target zone within the defined prediction time window and the currently effective dynamics, but will tend to move toward the target zone ("TargetZone not crossed, but high deviation in TargetZone direction"). The wheel's condition description will not hit the target zone within the defined prediction time window and will even tend to move away from the target zone ("TargetZone not crossed and high deviation from TargetZone away").

[0016] In some embodiments, the correction factors or elements of the at least one matrix are ordered by increasing slip and increasing wheel acceleration, and the at least one matrix has a first range whose elements have a correction factor of zero. The elements of the matrix can have an equidistant spacing of the slip and / or wheel acceleration values ​​and / or other spacing functions. Correction factors "between" the elements can be interpolated. The elements with a correction factor of zero are sometimes referred to as the target slip range. The use of such a matrix can contribute to good verifiability and / or modifiability of the drive control.

[0017] In some embodiments, the third value of the target wheel acceleration is a function of a sum of the first value and the second value. For example, the first and second values ​​can be checked for plausibility and, depending on this, summed. For example, if the first value is "hold" and the second value is "plus 5 Nm," the second value can be ignored or mapped to a "mitigation function." In some embodiments, the third value is a function of a limit on the sum of the first value and the second value. The limit can be applied, for example, if the summed target torque is too high, e.g., too high for the drivetrain or, e.g., differs too much from a target torque of another wheel on the axle. The limiting function can advantageously avoid inconsistencies and / or further improve the stability of the drive control.

[0018] In one embodiment, the method comprises further steps: detecting the third value for at least one situation, wherein the situation includes the wheel speed, the wheel acceleration, and, optionally, the wheel dynamics; comparing the third value with the corresponding correction factor of the at least one matrix; and if the slip is lower when using the third value than when using the corresponding correction factor of the at least one matrix, entering the third value into the corresponding element of the at least one matrix.

[0019] These additional steps can be performed, for example, during operation, or, with buffering, during a downtime and / or during maintenance. These steps can particularly utilize the inherent flexibility of the method, especially the matrix solution. These steps can advantageously contribute to continuous improvement of the drive control by using individual practical values ​​from this vehicle.

[0020] One aspect relates to a drive control system for controlling the drive of actuators of at least one wheel of a vehicle. The drive control system comprises: a signal acquisition unit configured to detect a wheel speed of the wheel and to detect a wheel acceleration and / or wheel dynamics. Furthermore, a further acquisition unit configured to detect a desired acceleration and a vehicle speed of the vehicle. The further acquisition unit can also be referred to as a target signal acquisition unit.

[0021] The drive control system further comprises a state determination unit configured to determine a state description of the wheel from the wheel speed and the wheel acceleration, and an action determination unit configured to determine a first value of a wheel target acceleration from the state description, a wheel slip, and the desired acceleration, wherein the slip is a function of the wheel speed and the vehicle speed. Furthermore, it comprises a correction unit comprising at least one matrix containing correction factors and configured to determine a second value of the wheel target acceleration. The first and second values ​​are sent to an actuator control unit configured to control the actuators of the at least one wheel based on a function of the first value and the second value.

[0022] One aspect relates to a vehicle having a drive control system as described above and / or below.

[0023] One aspect relates to a program element which, when executed on a drive control controller as described above and / or below, instructs the drive control controller to perform the method as described above and / or below.

[0024] One aspect relates to a computer-readable medium on which a program element as described above is stored.

[0025] Further measures improving the invention are presented in more detail below together with the description of the preferred embodiments of the invention with reference to figures. Examples of implementation

[0026] It shows: Fig. 1 schematically shows an image of a vehicle according to an embodiment; Fig. 2schematically shows a drive control system according to an embodiment; Fig. 3 schematically shows a matrix according to an embodiment; Fig. 4 a flowchart according to one embodiment.

[0027] Fig. 1shows a schematic image of a vehicle 100 according to one embodiment. The vehicle of the illustrated embodiment has - without restricting generality - four wheels 120 with brakes 140. The brakes 140 are controlled by actuators 490. In an exemplary alternative embodiment, the actuators 490 can, for example, also be part of the brakes 140; other embodiments are also possible. The vehicle 100 further comprises actuators 480, which can, for example, be part of the drive train. The vehicle 100 further comprises sensors 150 for a wheel speed v of each wheel 120, which can, for example, be arranged on the wheel 120 and / or on the axle. The sensors 150 can also provide a wheel acceleration a and / or a wheel dynamics j. Furthermore, the vehicle has one or more sensors 160 for a desired acceleration DrvReq, e.g., from an accelerator pedal, a joystick, an assistance system (e.g.a cruise control) and / or from other sources. In addition, the vehicle has one or more sensors 170 for a vehicle speed v GND of the vehicle 100. The signals from the sensors 150, 160, 170 are routed to inputs of a drive control controller 190. The signals 485, 495 from the drive control controller 190 are routed to the actuators 480, 490.

[0028] Fig. 2 shows schematic details of the drive control 190 of Fig. 1 .The same reference numerals denote the same or similar components. A signal acquisition unit 200, which is configured to detect a wheel speed v of the wheel 120 and, optionally, to detect a wheel acceleration a and / or a wheel dynamics j, receives from the sensors 150 for each of the wheels 120 signals 205 of the wheel speed v of each wheel 120 and, optionally, signals of the wheel acceleration a and / or the wheel dynamics j. If the signals a and j are not supplied by the sensors 150, these signals can be formed - e.g., by the signal acquisition unit 200. The signals v, a, j 215 are passed to a state determination unit 220, which is configured to determine a state description 225 of the wheel or each wheel 120 from v and a, optionally also from j.

[0029] The signals 305 of the sensors 150, 160, 170 are passed to a further detection unit 300, which is configured to detect the desired acceleration DrvReq (from the sensor 160) and a vehicle speed v GND (from the sensor 170) of the vehicle 100. A slip s can be formed by the detection unit 300 and / or by downstream components. The slip s can be formed for each of the wheels 120 as a function of the wheel speed v and the vehicle speed v GND. An action determination unit 250 determines a first value 275 of a wheel target acceleration from the state description 225, the slip s of the wheel 120, and the desired acceleration DrvReq. The first value 275 can, for example, be selected from a set {accelerate, decelerate, hold} or can comprise this set.A correction unit 360 determines a second value 375 of the target wheel acceleration from the wheel speed v, the wheel acceleration a, and the slip s. The correction unit 360 has at least one matrix 350 containing correction factors. The correction factors of the at least one matrix 350 can, for example, be ordered in ascending order of slip s and wheel acceleration a. "Gaps" in the matrix 350—for example, when no entry exists in the matrix 350 for a specific slip s and / or for a specific wheel acceleration a—can be "filled," for example, by interpolation.

[0030] The output signals 275, 375 of the action determination unit 250 and the correction unit 360, respectively, are sent to an actuator control unit 400. A summation unit 420 can sum the values ​​of the output signals 275, 375 and / or form a signal for each wheel 120 that is a function of the output signals 275, 375. A limiting unit 440 can limit the output signals of the summation unit 420, e.g., by means of a functional and / or plausibility check. The algorithms of these checks can, for example, consider a maximum power of the drivetrain 480 and / or the brakes 490, 140. The algorithms of these checks can, for example, consider functional relationships of the wheels 120, e.g., (mechanical and / or electronic) differentials. The output signals 485, 495 of the actuator control unit 400 are sent to the drive train 480 and the brakes 490, 140, respectively.

[0031] The drive control system 190 can optionally include a learning unit 450. The learning unit 450 can acquire one or more third values ​​485, 495 for at least one situation. The situation can include the wheel speed v, the wheel acceleration a, and, optionally, the wheel dynamics j. The learning unit 450 can compare the third value 485, 495 with the corresponding correction factor of the at least one matrix 350. Furthermore, if the slip s is lower when using the third value 485, 495 than when using the corresponding correction factor of the at least one matrix 350, an update of the third value 485, 495 can be entered into the corresponding element of the at least one matrix 350. This allows the learning unit 450 to learn from the "practical" drive control of this vehicle 100 and thus improve the control. Alternatively or additionally, further options for updating the one matrix 350 can be implemented.

[0032] The components of the drive control system 190 can be implemented as hardware, software, and / or a combination of hardware and software. The components can be spatially distributed or implemented in a single control device.

[0033] Fig. 3 schematically shows a matrix 350 according to one embodiment. The elements of the matrix 350 include correction factors that can contribute to the formation of the third value 375 for each wheel 120. The correction factors of the at least one matrix 350 are ordered according to increasing slip s (e.g., horizontal) and increasing wheel acceleration a (e.g., vertical). The matrix 350 can have a first region 351 whose elements have a correction factor of zero. The other regions of the matrix 350 can be characterized, for example, as follows: Area 352: Slip s is lower, wheel acceleration approximately zero; Area 353: Slip s is lower, wheel acceleration greater; Area 354: Slip s is approximately zero, wheel acceleration greater; Area 355: Slip s is higher, wheel acceleration greater; Area 356: Slip s is higher, wheel acceleration approximately zero; Area 357: Slip s is higher, wheel acceleration lower; Area 358: Slip s is approximately zero, wheel acceleration lower; Area 359: Slip s is lower, wheel acceleration lower.

[0034] The elements of the matrix can have an equidistant spacing of the slip and / or wheel acceleration values ​​and / or other spacing functions. Correction factors "between" the elements can be interpolated.

[0035] Fig. 4 shows a flowchart 500 according to an embodiment. In a step 502, the method starts. In a step 504, a desired acceleration DrvReq (see Fig. 2) is detected. In a step 506, a vehicle speed v GND of the vehicle 100 is detected. In a step 508, a wheel speed v of the wheel 120 is detected. Steps 504, 506, 508 can be performed essentially in parallel.

[0036] In a step 510, a state description 225 of the wheel 120 is determined from the wheel speed v and a wheel acceleration a. The state description 225 includes a static description 226, which is a function of the wheel speed v and the wheel acceleration a. In a step 512, a first value 275 of a wheel target acceleration is determined from the state description 225, a slip s of the wheel 120, and the desired acceleration DrvReq. The slip s is a function of the wheel speed v and the vehicle speed v GND . In a step 514, a second value 375 of the wheel target acceleration is determined from the wheel speed v, the wheel acceleration a, and the slip s, the second value being a function of correction factors of at least one matrix 350. Steps 510, 512, and step 514 can be performed essentially in parallel.

[0037] In a step 516, a third value 585, 595 of the wheel target acceleration is determined, which controls the actuators 580, 590 of the at least one wheel 120, wherein the third value 585, 595 is a function of the first value 275 and the second value 375. Steps 502 to 516 can be repeated regularly, e.g., periodically, e.g., every 1 ms, 2 ms, 5 ms, and / or with a different periodicity or cycle time.

Claims

1. Method for the drive control of actuators (490, 480) of at least one wheel (120) of a vehicle (100), comprising the following steps: sensing a desired acceleration (DrvReq); sensing a vehicle velocity (vGND) of the vehicle (100); sensing a wheel velocity (v) of the wheel (120); determining a description of the condition (225) of the wheel (120) from the wheel velocity (v) and a wheel acceleration (a), wherein the description of the condition (225) includes a static description (226) which is a function of the wheel velocity (v) and the wheel acceleration (a); determining a first value (275) of a target wheel acceleration from the description of the condition (225), a slip (s) of the wheel (120) and the desired acceleration (DrvReq), wherein the slip (s) is a function of wheel velocity (v) and the vehicle speed (v GND); characterized in that the method comprises the following additional steps: determining a second value (375) of the target wheel acceleration from the wheel velocity (v), the wheel acceleration (a) and the slip (s), wherein the second value is a function of correction factors of at least one matrix (350); and determining a third value (485, 495) of the target wheel acceleration, which third value controls the actuators (480, 490) of the at least one wheel (120), wherein the third value (485, 495) is a function of the first value (275) and the second value (375).

2. Method according to Claim 1, wherein the description of the condition (225) of the wheel (120) furthermore includes a dynamic description (227) which is a function of the wheel acceleration (a) and wheel dynamics (j).

3. Method according to Claim 2, wherein the description of the condition (225) of the wheel (120) furthermore includes a predictive description (228) which is a function of the wheel dynamics (j).

4. Method according to one of the preceding claims, wherein the correction factors of the at least one matrix (350) are sorted by ascending slip (s) and by ascending wheel acceleration (a), and wherein the at least one matrix (350) includes a first region (351) whose elements have a correction factor of zero.

5. Method according to one of the preceding claims, wherein the third value (485, 495) of the target wheel acceleration is a function of a sum of the first value (275) and the second value (375).

6. Method according to Claim 5, wherein the third value (485, 495) is a function of a limiting of the sum of the first value (275) and the second value (375).

7. Method according to one of the preceding claims, comprising the following additional steps: sensing the third value (485, 495) of the target wheel acceleration for at least one situation, wherein the situation includes the wheel velocity (v), the wheel acceleration (a) and, optionally, the wheel dynamics (j); comparing the third value (485, 495) with the corresponding correction factor of the at least one matrix (350); and if the slip (s) when using the third value (485, 495) is lower than when using the corresponding correction factor of the at least one matrix (350), entering an update of the third value (485, 495) into the corresponding element of the at least one matrix (350).

8. Drive-control control system (190) for the drive control of actuators (490, 480) of at least one wheel (120) of a vehicle (100), the drive-control control system (190) comprising the following: a signal sensing unit (200) which is designed to sense a wheel velocity (v) of the wheel (120) and, optionally, to sense a wheel acceleration (a) and / or wheel dynamics (j); an additional sensing unit (300) which is designed to sense a desired acceleration (DrvReq) and a vehicle velocity (v GND) of the vehicle (100); a condition determining unit (220) which is designed to determine a description of the condition (225) of the wheel (120) from the wheel velocity (v) and the wheel acceleration (a); an action determining unit (250) which is designed to determine a first value (275) of a target wheel acceleration from the description of the condition (225), a slip (s) of the wheel (120) and the desired acceleration (DrvReq), wherein the slip (s) is a function of the wheel velocity (v) and the vehicle velocity (vGND); characterized in that the drive-control control system also comprises a correction unit (360), comprising at least one matrix (350) which contains correction factors and which is designed to determine a second value (375) of the target wheel acceleration; and an actuator control unit (400) which is designed to control the actuators (480, 490) of the at least one wheel (120) from a function of the first value (275) and the second value (375).

9. Vehicle (100), comprising a drive-control control system (190) according to Claim 8.

10. Program element which, when executed on a drive-control control system (190) according to Claim 8, instructs the drive-control control system (190) to carry out the method according to any one of Claims 1 to 7.

11. Computer-readable medium on which a program element according to Claim 10 is stored.