Motion and torque control architecture for mobile platforms with distributed torque actuators

Abstract

A motor vehicle includes first and second drive axles coupled to respective sets of wheels, torque actuators including rotary electric machines configured to transmit respective output torques to the drive axles, and a main controller in communication with the torque actuators. The controller receives vehicle inputs indicating total longitudinal and lateral motion requests. In response, the controller calculates a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request, and then uses a cost optimization function to determine a torque vector that allocates the total longitudinal torque request and / or velocity request, the yaw rate request, and the lateral velocity request to the drive axles within predetermined constraints. The controller also transmits closed-loop control signals to each torque actuator or its local controller to apply the torque vector via the drive axles.

Description

Technical Field

[0001] The present disclosure relates to a motion and torque control architecture for a mobile platform having distributed torque actuators. Background Art

[0002] Rotating electric machines are used as torque actuators in a wide range of electrified powertrains to generate and receive torque during respective discharging and charging operating modes. Battery electric vehicles and hybrid electric vehicles, in particular, typically include an electric propulsion motor whose output shaft is coupled to a driven axle. In some electrified powertrain configurations, multiple electric propulsion motors may be used alone or in combination with an internal combustion engine. When various electric propulsion motors are coupled to respective driven axles and / or wheels, the resulting configuration is referred to in the art as an electric all-wheel drive (eAWD) propulsion system. Summary of the Invention

[0003] Disclosed herein are systems, associated control logic, and methods for controlling the real-time operation of a motor vehicle or other mobile platform having distributed / axle-specific torque actuators (including rotary electric machines in an exemplary electric all-wheel drive (eAWD) propulsion system). Unlike powertrain systems where a centralized propulsion system controller analyzes and implements longitudinal vehicle torque actuation requests for individual axle propulsion, such as via a single electric propulsion motor coupled to a rear drive axle or a front drive axle, an eAWD propulsion system has multiple independently actuated drive axles, some of which may include individually actuated half-axles, to provide independent four-corner control in a typical vehicle configuration.

[0004] As eAWD propulsion systems evolve and implement fast actuator technologies, a new torque dispatching strategy and control architecture are needed to coordinate the actuation activities of the various electric propulsion motors arranged on the different drive axles, particularly in a manner that takes into account both longitudinal and lateral vehicle control objectives. Within the scope of the present disclosure, the ability to control additional actuators can be included, but not necessarily limited to, axle-specific or wheel-specific brake actuators, steering actuators, active aerodynamic and / or roll control actuators, and the like. In general, such actuators are controlled according to model-generated torque vectoring to optimally influence vehicle / platform dynamics as described herein.

[0005] The eAWD propulsion system described herein includes a plurality of drive axles, each of which is independently coupled to and actuated by a corresponding torque actuator in the form of at least a rotary electric motor. Other representative embodiments also include brake actuators and steering actuators as part of the collective group of torque actuators contemplated herein. Within such a propulsion system, the electric motor is configured to act as an electric propulsion / traction motor in a discharge / propulsion mode (i.e., when the onboard high-voltage battery pack, fuel cell, or other power source is discharged at a controlled rate to power the electric motor). As is understood in the art, such an electric motor may also act as a generator, as required by its capabilities, i.e., during a power generation mode of operation.

[0006] In particular, the present teachings relate to a controller-implemented architecture that incorporates longitudinal torque and lateral motion control objectives into a single, multi-axle torque distribution optimization strategy. The disclosed strategies, many of which are executed by a master controller in communication with distributed local / actuator-level control units, such as the motor control processors (MCPs) of the aforementioned electric motors, simultaneously optimize driving performance for both longitudinal and lateral vehicle dynamics. Torque distribution is subject to calibrated performance constraints, including hardware limitations, axle interventions, dynamic, thermal, and / or electrical limitations, and / or external requestor limitations as described herein.

[0007] In a representative embodiment, a motor vehicle includes first and second drive axles coupled to first and second sets of wheels, respectively, and a plurality of torque actuators including rotary electric machines, each torque actuator configured to transmit a respective output torque to the first and / or second drive axles. Contemplated herein, torque actuators may also include, for example, steering actuators, brake actuators, and / or other application-appropriate torque actuators acting on the individual drive axles and / or wheels coupled thereto.

[0008] A master controller is in communication with the torque actuator and is programmed with calibrated constraints. The master controller is configured to: receive a set of vehicle inputs indicative of a total longitudinal motion request and a total lateral motion request for the motor vehicle; and calculate a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the vehicle inputs.

[0009] The master controller also determines an optimal torque vectoring and optimal set points for other considered actuators using a cost optimization function. The torque vectoring dispatches the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first and / or second driven axles within / constrained by a calibrated set of constraints. The master controller then transmits closed-loop control signals to each of the torque actuators or their associated local control processors to apply the torque vectoring via the first and / or second driven axles.

[0010] The torque actuator may include a first motor coupled to a first drive axle and a second motor coupled to a second drive axle. In such an embodiment, the first drive axle and / or the second drive axle may include a pair of corresponding half-axles. The first motor and / or the second motor may include a pair of corresponding motors, each coupled to a corresponding one of the half-axles.

[0011] The torque actuator may optionally include one or more brake actuators connected to a respective one of the first drive axle and the second drive axle.

[0012] In an exemplary configuration, the above constraints may include separate hardware constraints, operational constraints, and / or external functional constraints.

[0013] In some embodiments, the torque vectoring is configured to optimize wheel slip of the first and / or second set of wheels.

[0014] The cost optimization function executed by the main controller can be configured to optimize torque vectoring for the current tire capacity of the first and / or second set of wheels. The cost optimization function can also be configured to optimize torque vectoring for propulsion efficiency of the motor vehicle, or for other results in different embodiments.

[0015] In a possible configuration, the first and second sets of wheels are respective front and rear wheels, either or both of which are independently steerable via respective steering actuators. In such a configuration, the torque actuators may comprise respective steering actuators.

[0016] The selectable mode selection device may be configured to receive an operator-requested or autonomously-requested mode selection signal, wherein the master controller is configured to modify the weights within the cost optimization function in response to the mode selection signal.

[0017] In a possible variation, the torque actuator may include an internal combustion engine configured to generate an engine output torque, and at least one electronically controlled differential coupled to the internal combustion engine. In such an embodiment, the electronically controlled differential may be configured to receive the engine output torque therefrom.

[0018] Also disclosed herein is a method for controlling motion and torque in a motor vehicle having an eAWD propulsion system as described above. The method includes receiving, via the master controller, a set of vehicle inputs, wherein the vehicle inputs indicate a total longitudinal motion request and a total lateral motion request for the motor vehicle. In this representative embodiment, the constraints include hardware constraints, operational constraints, and / or external functional constraints.

[0019] The method includes calculating a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the set of vehicle inputs. The method also includes determining, using a cost optimization function, a torque vector for dispatching the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first and second driven axles within a calibrated set of constraints. Additionally, the method includes transmitting a closed-loop control signal to each of the torque actuators to apply the torque vector via the first and second driven axles, respectively.

[0020] The above and other features and advantages of the present disclosure are readily apparent from the following detailed description of embodiments and the best mode for carrying out the disclosure, when considered in conjunction with the accompanying drawings and the appended claims.

[0021] The present invention also includes the following technical solutions.

[0022] Technical Solution 1. A motor vehicle comprising:

[0023] a first drive axle coupled to the first set of wheels;

[0024] a second drive axle coupled to a second set of wheels;

[0025] a plurality of torque actuators each connected to the first drive axle or the second drive axle and configured to transmit a corresponding output torque to the first drive axle and / or the second drive axle, the plurality of torque actuators comprising a plurality of rotary electric machines; and

[0026] a master controller in communication with the plurality of torque actuators, wherein the master controller is programmed with a calibrated set of constraints and is configured to:

[0027] receiving a set of vehicle inputs indicative of a total longitudinal motion request and a total lateral motion request for the motor vehicle;

[0028] calculating a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the set of vehicle inputs;

[0029] determining, using a cost optimization function, a torque vector for apportioning the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first driven axle and the second driven axle within a calibrated set of constraints; and

[0030] A closed-loop control signal is transmitted to each of the torque actuators to apply the torque vectoring via the first and second drive axles, respectively.

[0031] Technical Solution 2. The motor vehicle according to Technical Solution 1, wherein the plurality of rotating electrical machines include a first electric propulsion motor coupled to the first drive axle and a second electric propulsion motor coupled to the second drive axle.

[0032] Technical Solution 3. A motor vehicle according to Technical Solution 2, wherein the first drive axle and / or the second drive axle includes a pair of corresponding half-axles, and wherein the first electric propulsion motor and / or the second electric propulsion motor includes a pair of corresponding electric propulsion motors each coupled to a corresponding one of the half-axles.

[0033] Technical Solution 4. The motor vehicle according to Technical Solution 1, wherein the plurality of torque actuators include one or more brake actuators connected to a respective one of the first drive axle and the second drive axle.

[0034] Technical Solution 5. The motor vehicle according to Technical Solution 1, wherein the constraint set includes hardware constraints, operation constraints and / or external functional constraints.

[0035] Technical Solution 6. The motor vehicle according to Technical Solution 1, wherein the torque vectoring is configured to optimize wheel slip of the first group of wheels and / or the second group of wheels.

[0036] Technical Solution 7. The motor vehicle according to Technical Solution 1, wherein the cost optimization function is configured to optimize the torque vectoring for current tire capacities of the first set of wheels and the second set of wheels.

[0037] Technical Solution 8. The motor vehicle according to Technical Solution 1, wherein the cost optimization function is configured to optimize the torque vectoring for propulsion efficiency of the motor vehicle.

[0038] Technical Solution 9. A motor vehicle according to Technical Solution 1, wherein the first group of wheels and the second group of wheels are corresponding front and rear wheels, the first group of wheels and / or the second group of wheels can be steered via corresponding steering actuators, and the multiple torque actuators include corresponding steering actuators.

[0039] Technical Solution 10. The motor vehicle according to Technical Solution 1 further comprises: a mode selection device configured to receive an operator-requested or autonomously-requested mode selection signal, wherein the controller is configured to modify the weight within the cost optimization function in response to the mode selection signal.

[0040] Technical Solution 11. A motor vehicle according to Technical Solution 1, wherein the multiple torque actuators include an internal combustion engine configured to generate an engine output torque including the output torque, and an electronically controlled differential coupled to the internal combustion engine, the electronically controlled differential being configured to receive the engine output torque therefrom.

[0041] Technical Solution 12. A method for controlling motion and torque in a motor vehicle, the motor vehicle having a first drive axle coupled to a first set of wheels, a second drive axle coupled to a second set of wheels, and a plurality of torque actuators each connected to the first drive axle and / or the second drive axle, the plurality of torque actuators including a plurality of rotary electric machines configured to transmit respective output torques to the first drive axle and / or the second drive axle, the method comprising:

[0042] receiving, via a master controller programmed with a calibrated set of constraints, a set of vehicle inputs indicative of a total longitudinal motion request and a total lateral motion request for the motor vehicle, the set of constraints comprising hardware constraints, operational constraints, and / or external functional constraints;

[0043] calculating a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the set of vehicle inputs;

[0044] determining, using a cost optimization function, a torque vector for apportioning the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first driven axle and the second driven axle within a calibrated set of constraints; and

[0045] A closed-loop control signal is transmitted to each of the torque actuators to apply the torque vectoring via the first and second drive axles, respectively.

[0046] Technical Solution 13. A method according to Technical Solution 12, wherein the multiple rotating electrical machines include a first electric propulsion motor coupled to the first drive axle and a second electric propulsion motor coupled to the second drive axle, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting the closed-loop control signal to the first electric propulsion motor and the second electric propulsion motor.

[0047] Technical Solution 14. A method according to Technical Solution 12, wherein the first drive axle and / or the second drive axle include a pair of corresponding half-axles, and the first electric motor and / or the second electric propulsion motor include a pair of corresponding electric propulsion motors each coupled to a corresponding one of the half-axles, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting the closed-loop control signal to a pair of corresponding electric propulsion motors.

[0048] Technical Solution 15. A method according to Technical Solution 12, wherein the multiple torque actuators include one or more brake actuators connected to a corresponding one of the first drive axle and the second drive axle, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting a closed-loop braking control signal to the one or more brake actuators.

[0049] Technical Solution 16. The method according to Technical Solution 12, wherein determining the torque vector for dispatching the total longitudinal torque request and / or the total longitudinal speed request includes optimizing the wheel slip of the first group of wheels and / or the second group of wheels via the cost optimization function.

[0050] Technical Solution 17. The method according to Technical Solution 12, wherein determining the torque vector for dispatching the total longitudinal torque request and / or the total longitudinal speed request includes optimizing the torque vector for current tire capacities of the first group of wheels and the second group of wheels.

[0051] Technical Solution 18. The method according to Technical Solution 12, wherein determining the torque vector for dispatching the total longitudinal torque request and / or the total longitudinal speed request includes optimizing propulsion efficiency of the motor vehicle.

[0052] Technical Solution 19. A motor vehicle according to Technical Solution 1, wherein the first group of wheels and the second group of wheels are corresponding front and rear wheels, the first group of wheels and / or the second group of wheels can be steered via corresponding steering actuators, and the multiple torque actuators include corresponding steering actuators, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting the closed-loop steering control signal to the corresponding steering actuator.

[0053] Technical Solution 20. A method according to Technical Solution 12, wherein the motor vehicle includes a mode selection device configured to receive an operator-requested or autonomously-requested mode selection signal, and the method further includes: automatically adjusting the weight within the cost optimization function via the main controller in response to the mode selection signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic illustration of an exemplary motor vehicle having an electric all-wheel drive (eAWD) propulsion system and a primary controller configured to perform the present method.

[0055] Figure 2 Is used to describe Figure 1 Flowchart of an exemplary method for dispatching torque in an eAWD propulsion system.

[0056] Figure 3 It is a diagram showing the implementation of this method with Figure 1 A schematic logic flow diagram of exemplary control logic for use with a motor vehicle. DETAILED DESCRIPTION

[0057] The present disclosure is susceptible of many different forms of embodiment. Representative examples of the present disclosure are shown in the accompanying drawings and are described in detail herein as non-limiting examples of the disclosed principles. For this purpose, elements and limitations described in the Abstract, Introduction, Summary, and Detailed Description sections of the specification but not explicitly stated in the claims should not be incorporated into the claims, either individually or collectively, by implication, inference, or otherwise.

[0058] For the purposes of this specification, unless specifically denied, the use of the singular includes the plural, and vice versa; the terms "and" and "or" shall be both conjunctions and transitional conjunctions; "any" and "all" shall mean "any and all"; and the words "including," "comprising," "including," "having," and the like shall mean "including but not limited to." In addition, approximate words (such as "about," "almost," "substantially," "roughly," "approximately," and the like) may be used herein in the sense of "at, approximately, or nearly," or "within 0-5%," or "within acceptable manufacturing tolerances," or their logical combinations thereof.

[0059] Referring to the drawings, wherein like reference numerals refer to like parts, Figure 1 A representative motor vehicle 10 or another mobile platform having an electric all-wheel drive (eAWD) propulsion system 11 configured as described herein is schematically depicted. The eAWD propulsion system 11 includes a plurality of rotating electric machines (MEs) 114E, including, in a simplified embodiment, rear propulsion motors 14 and front propulsion motors 114. The eAWD propulsion system 111 is driven by a plurality of rotating electric machines (MEs) 114E, including, in a simplified embodiment, rear propulsion motors 14 and front propulsion motors 114E ... O ) real-time adjustment of the main torque function of the motor 114E. The instructions for implementing the torque distribution control strategy according to the present disclosure are implemented as a method 100, an example of which is shown in Figure 2Such instructions may be recorded in a memory (M) of a controller 50 programmed with a cost optimization function 51 as set forth in detail below and executed by one or more processors (P) using associated control logic 50L to provide the benefits described herein.

[0060] Other powertrain components may be included within the eAWD propulsion system 11, such as, but not limited to, a motor with a motor that provides engine torque (arrow T) in a possible hybrid-electric configuration. E ) of the optional internal combustion engine (E) 200 of the output shaft 201, and the DC-DC converter (DC-DC) 18 and the auxiliary battery (B AUX ) 160. As is understood in the art, high voltage propulsion operations may require voltage levels of 300V or above, while on-board low voltage / auxiliary functions are typically powered by a 12-15V power supply. Therefore, as used herein, "low voltage" and "auxiliary voltage" refer to nominal 12V power levels, while "high voltage" refers to voltage levels that significantly exceed the auxiliary voltage levels. Therefore, as is understood in the art, the DC-DC converter 18 can operate through internal switching operations and signal filtering to receive a relatively high DC voltage from the DC voltage bus (VDC) and output an auxiliary voltage to the auxiliary battery 160.

[0061] Figure 1 The representative motor vehicle 10 includes front wheels 15F arranged on a front drive axle 119F, and rear wheels 15R arranged on a rear drive axle 119R. Depending on the configuration, electronically controllable differentials 30 and / or 130 can be used to select the engine torque (arrow T) from the motor 114E in different drive modes. E ) and / or output torque (arrow T O ) are assigned to the front wheels 15F and / or the rear wheels 15R of the motor vehicle 10.

[0062] In some embodiments, the front drive axle 119F and the rear drive axle 119R can be implemented as half-axles 119F-1 and 119F-2 for the front drive axle 119F, and as half-axles 119R-1 and 119R-2 for the rear drive axle 119R. In such embodiments, the half-axles 119F-1 and 119F-2 can be connected to an electronically controllable differential 130. The half-axles 119R-1 and 119R-2 can be connected to the electronically controllable differential 30, wherein this configuration enables independent torque distribution to the front wheels 15F and / or the rear wheels 15R as part of the method 100. In various embodiments, this strategy can be extended to the following configurations: (1) a configuration using a single propulsion source (e.g., motor 114E) attached to an electronic limited slip differential (eLSD), which allows torque variation between the left and right sides of a given driven axle, and (2) separate motors 114E, each directly connected to one of the wheels 15R or 15F, i.e., with no mechanical connection between the left and right sides. Therefore, option (2) forgoes the use of differentials 30 and 130 described above.

[0063] In some embodiments, schematically shown for clarity and simplicity of illustration, the front and rear wheels 15F, 15R can be independently steered via corresponding steering actuators 26. Similarly, the front and rear wheels 15F, 15R can be independently decelerated via corresponding brake actuators 26. Such brake actuators 26 can be independently controlled and connected to a given wheel 15F or 15R or half-axle 119F-1, 119F-2, 119R-1, 119R-2, or a single brake actuator 26 can prevent rotation of the wheel 15F or 15R coupled to a given drive axle 119F or 119R, for example, as an electronic brake actuator. Thus, for applications where torque from a propulsion actuator (such as motor 114E) is not available on the individual axles, some degree of torque control is still possible via brake actuators 26.

[0064] The steering actuator 25 and the brake actuator 26 respond to the pressure or travel of the accelerator pedal 22A and the brake pedal 22B, respectively, and generate corresponding accelerator request signals (arrow A X ) and brake request signal (arrow B X The operator of the motor vehicle 10 can use the steering wheel 22S to influence the steering angle (arrow θ X ), the steering angle is read by the main controller 50 together with the accelerator request signal (arrow A X ) and brake request signal (arrow B X ) together as a set of input signals (arrow CC I The main controller 50 may also receive a mode selection signal (arrow M) from an optional mode selection device (MSD) 22M.X ) as input signal (arrow CC I ) as part of the present invention, the operation of the mode selection device 22M is described in more detail below.

[0065] Still refer to Figure 1 In an embodiment, an eAWD propulsion system 11 is shown in which a front propulsion motor 114 is connected to a front drive axle 119F via an output member 117 (e.g., a rotating shaft and possibly a gear set). The front propulsion motor 114 can be implemented as an alternating current (AC) device in which a wound stator 114S is supplied from an onboard direct current (DC) power source (in Figure 1 A representative high voltage battery pack (B HV ) 16, for example, a multi-cell lithium-ion battery) draws single-phase or multi-phase current. In this embodiment, the battery pack 16 is connected to the wound stator 114S via a traction power inverter module (TPIM-2) 20-2, wherein the corresponding motor control processor (MCP-2) responds to the output signal (arrow CC O ) locally controls the output torque and rate of the front propulsion motor 114. Once energized, the wound stator 114S generates a rotating electromagnetic field that interacts with the field of the magnetic rotor 114R, which can be surrounded by the wound stator 114S in a typical rotating flux configuration.

[0066] The eAWD propulsion system 11 can employ a similar arrangement to power the rear wheels 15R. For example, the rear propulsion motor 14 can include a rotor 14R surrounded by a wound stator 14S, wherein the rear propulsion motor 14 is energized via a corresponding TPIM-1 20-1 having a resident / local motor control processor (i.e., MCP-1). As shown, the rear propulsion motor 14 can be coupled to the differential 30 via an output member 17, wherein the output member 17 transmits its own output torque (arrow T O ) is transmitted to the rear wheel 15R.

[0067] In a possible alternative configuration, independent torque control can be provided to individual rear wheels 15R by arranging separate rear propulsion motors 14-1 and 14-2 on respective half-axles 119R-1 and 119R-2. In such an embodiment, instead of using a single TPIM 20-1 for a single rear propulsion motor 14, rear propulsion motors 14-1 and 14-2 can be individually connected to corresponding TPIMs 20-1A and 20-1B (TPIM-1A and TPIM-1-B, respectively). Although omitted for clarity of illustration, those skilled in the art will appreciate that the single front propulsion motor 114 can similarly be replaced by a separate electric propulsion motor coupled to each of half-axles 119F-1 and 119F-2 to independently power the front wheels 15F on opposite sides of the motor vehicle 10.

[0068] The term "controller" as used herein for simplicity of description may include one or more electronic control modules, units, processors and their associated hardware components, such as application specific integrated circuits (ASICs), systems on a chip (SoCs), electronic circuits, and other hardware required to provide programmed functions. Figure 1 In the representative three-motor configuration shown in the embodiment of FIG, the master controller 50 may be for a drive axle with a single drive unit (e.g., in a vehicle using Figure 1 In one embodiment, the motor controller for the electric propulsion motor 114 (in this embodiment, the front drive axle 119F) is configured to be a motor controller. This arrangement can help ensure balanced controller area network (CAN) communication delays between the main controller 50 and the various secondary controllers (e.g., MCP-1, MCP-1A, MCP-1B, and MCP-2) communicating therewith, as well as the local controllers for the brake actuator 26 and the steering actuator 25. Axle-based control functions can then be dispatched to such local controllers to enable faster local feedback-based control of the individually driven axles 119F, 119R, 119F-1, 119F-2, 119R-1, and / or 119R-2, allowing for real-time or preemptive management of wheel slip and other rapid dynamics.

[0069] Figure 1 The main controller 50 (representative control logic 50L for which is shown in FIG. Figure 3 in) can be implemented as an input signal (arrow CC I ) to which one or more electronic control units or computing nodes respond. The controller 50 includes an application-specific amount of memory (M) and one or more processors (P) (e.g., a microprocessor or central processing unit), as well as other associated hardware and software, such as a digital clock or timer, input / output circuitry, buffer circuitry, etc. The memory (M) may include a sufficient amount of read-only memory, such as magnetic or optical memory.

[0070] Figure 2 and Figure 3 A method 100 according to an exemplary embodiment and a corresponding set of control logic 50L for implementing the method 100 on the motor vehicle 10 are depicted respectively. Figure 2 The method 100 is designed to incorporate lateral vehicle dynamics objectives into the torque control framework actively executed by the master controller 50. As part of this strategy, lateral motion objectives such as desired yaw rate and lateral velocity are used as optimization targets. This occurs in addition to the traditional longitudinal targets typically determined using the driver's total torque and velocity request.

[0071] In particular, execution of the method 100 involves multi-objective optimization / arbitration to determine multiple axles (such as Figure 1 Then, after optimization, axle-based arbitration is used to provide additional flexibility to enforce external axle-based intervention or other performance limits as needed to protect underlying hardware, operating limitations, stability or other dynamic limitations, etc.

[0072] refer to Figure 2 The master controller 50 communicates with local controllers of a plurality of torque actuators, including the aforementioned motor 114E, and possibly the brake actuator 26 and / or the steering actuator 25, the electronically controllable differentials 30 and 130, and the like. Figure 2 At block B102 of FIG. 1 , the master controller 50, previously programmed with a calibrated set of constraints, is configured to receive the set of vehicle inputs ( Figure 1 Arrow CC I ), the set of vehicle inputs is exemplified as the total requested torque (T REQ ) and / or total rate request (N REQ ) and the lateral motion request (MOT) of the motor vehicle 10 LAT ).

[0073] In a typical usage scenario, for example, Figure 1 A driver of the motor vehicle 10 may generate a total torque request (T) using acceleration and braking requests, for example, by depressing the accelerator pedal 22A and the brake pedal 22B. REQ ) and the total rate request (N REQ ). Lateral Movement Request (MOT) LAT ) can be partially used Figure 1 Steering angle (arrow θ X ) is determined. In autonomous embodiments, such vehicle inputs ( Figure 1 Arrow CC I ) may be automatically generated by the main controller 50 and / or another dedicated control unit. The method 100 then proceeds to block B104.

[0074] At block B104, the master controller 50 calculates individual total lateral and longitudinal torque or motion requests (T and T, respectively) using the set of vehicle inputs from block B102. LAT and T LONG As part of block B104, the master controller 50 may again use the steering angle (arrow θ X ) are used as relevant inputs to calculate the yaw rate request and lateral speed request of the motor vehicle 10. Then, the method 100 proceeds to block B106.

[0075] In this embodiment, Figure 2Block B105 includes estimating the current state of the motor vehicle 10 (EST ST 10 As is known in the art, state estimation is typically used in vehicle applications to monitor, for example, current speed, attitude (pitch, yaw, and roll), current state of various propulsion units (e.g., motor 114E, engine 200, etc.), state of charge, temperature, voltage, current, and / or other relevant electrical parameters, in this case Figure 1 The state estimate may also take into account tire pressure and capacity, current or impending wheel slip of one or more of wheels 15R and 15F, and the like. Using a trajectory of such values, the master controller 50 is able to predict the state of the motor vehicle 10 at a future time. Thus, the current state of the motor vehicle 10 is fed into Figure 1 The cost optimization function 51 enables the main controller 50 to know the current state before starting the optimization calculation specific to the method 100.

[0076] Block B106 of method 100 includes using Figure 1 The cost optimization function (f OPT ) 51 determines, via the master controller 50, a torque vectoring scheme for dispatching the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the front driven axle 119F and / or the rear driven axle 119R within the above-described calibrated constraint set. As used herein and in the art, for example, torque vectoring for simplifying a three-motor / two-axle system may be = [A, B, C], where A, B, and C are the torques assigned to the different driven axles A, B, and C.

[0077] As will be understood in the art, there are numerous cost function-based optimization strategies that utilize dynamic models in the form of mathematical equations to optimize a given outcome in the presence of competing values and constraints. By way of example, the dynamic model used for optimization provides the dynamic relationships between manipulated actuators (e.g., torque distribution, friction brake torque, rear steering, etc.), as well as vehicle dynamics (such as longitudinal speed / acceleration, lateral speed / acceleration, yaw rate, wheel velocity, etc.). Optimization, as implemented herein, can use such dynamic models to predict expected vehicle responses based on actuator setpoints and then select appropriate actuator setpoints that jointly optimize a cost function 51 for the predicted trajectory. To implement the cost optimization function 51 used herein, for example, the master controller 50 can be programmed with relevant tracking functions for, for example, a desired longitudinal speed, longitudinal torque request, desired yaw rate, etc., while constraining against the aforementioned set of constraints.

[0078] Constraints can be both soft and hard, depending on whether they can occasionally be violated (soft constraints) or cannot be violated (hard constraints). The optimization considers all costs within the cost function 51 simultaneously and finds the optimal actuator setpoint (e.g., the corresponding torque vector) that minimizes the costs and provides the best compromise between the objectives. Penalties can be applied in real time by increasing the weight of certain factors (such as energy consumption or stability) (e.g., by adjusting the numerical weights in the mathematical equations).

[0079] Example constraints that the master controller 50 may consider may include, but are not limited to, tracking the most efficient torque distribution between the drive axles 119F and 119R and / or the various wheels 15F and 15R, constraining wheel slip to a given slip ratio, constraining each assigned axle torque to the corresponding estimated tire capacity, constraining longitudinal speed for overspeed control, or constraining total torque to enforce external total torque constraints. Since such considerations may be mathematically modeled in various forms, in non-limiting embodiments, optimization within the scope of the present disclosure, and therefore the optimal solution to a given set of dynamic modeling equations, may require finding the lowest cost solution.

[0080] As part of block B106, the master controller 50 may receive a mode selection signal ( Figure 1 Arrow M X ), whether operator-requested or autonomously requested. The master controller 50 can then modify the weights within the aforementioned cost optimization function in response to the mode selection signal. For example, if the driver selects "Sport Mode," lateral performance objectives such as meeting the driver's desired yaw rate may take precedence over factors such as powertrain efficiency, with unitless weights penalizing or favoring, respectively, certain combinations of torque actuation to achieve the performance desired for the indicated mode.

[0081] Likewise, at block B106, torque vectoring may be optimized for wheel slip at the front wheels 15F and / or rear wheels 15R in a similar manner, such as by penalizing a distribution that would result in wheel slip or would exacerbate an existing wheel slip condition at one or more of the wheels 15F and / or 15R. For example, to simultaneously avoid exceeding a slip ratio threshold at one wheel 15F or 15R while still satisfying the driver's total torque request, the optimization function 51 automatically changes the torque distribution to place more torque on the wheel 15F or 15R with less slip and less torque on the wheel 15F or 15R that exceeds the slip ratio.

[0082] Similarly, block B106 may require optimizing torque vectoring for the current tire capacities of the front wheels 15F and / or rear wheels 15R, which may preempt slip conditions. In this case, the optimization function 51 will predict, based on the current tire capacities and the vehicle dynamics model used by the optimization function 51, that some potential torque distributions will result in unacceptable wheel slip at some wheels 15F or 15R, thereby negatively impacting the ability of the motor vehicle 10 to meet the driver's longitudinal torque or velocity request. Consequently, the optimization will automatically avoid potential distributions such as minimizing the cost function and will instead find other distributions that better meet the driver's longitudinal torque or velocity request. That is, the torque distribution to the different axles can be optimized for wheel slip, with possible control actions including proactive distribution of torque based on knowledge of the tire capacity at each wheel, as well as reactive distribution when excessive slip is actually observed at any wheel.

[0083] The master controller 50 may also optimize torque vectoring for propulsion efficiency of the motor vehicle 10 (ie, by returning a solution that favors energy efficiency over other factors such as speed or cornering performance). The latter optimization may reduce the penalty for e.g. Figure 1 The electrical efficiency of the battery pack 16 or, in embodiments where the eAWD propulsion system 11 includes an engine 200 , the torque dispatch will increase electrical energy or fuel consumption.

[0084] One can think of illustrative examples of combining efficiency considerations with one or more other objectives, where compromises or trade-offs are made in the manner set out above. For example, one might consider Figure 1 Consider a scenario where motor vehicle 10 is traveling straight down a highway. In this case, motor vehicle 10 will follow the most efficient torque distribution, as it is also optimal for the driver's desired longitudinal and lateral response. Alternatively, the same driver may attempt an aggressive cornering maneuver. In this case, the most efficient torque distribution may not meet the driver's desired longitudinal and lateral response. Therefore, optimization function 51 and the accompanying control strategy will compromise between efficiency and lateral demands based on the degree to which each is weighted.

[0085] exist Figure 2 After performing this optimization at block B106, method 100 proceeds to block B108, where the master controller 50 determines external limits or axle interventions. Such limits may be communicated to the master controller 50 from a different control unit (e.g., an electronic stability control or traction control module), or they may originate from a different function resident on the master controller 50. Limits may include calibrated hardware limits designed to protect the structural integrity of various components of the eAWD propulsion system 11, such as associated thermal, torque, acceleration, or other suitable thresholds, as well as dynamic limits to account for stability, traction, or other performance limitations.

[0086] In summary, the limitations considered in block B108 are then applied at block B109 (LIM) to adjust the torque vectoring output of block B108 as needed to account for the limitations. The method 100 then proceeds to block B110.

[0087] Block B110 includes implementing axle-based arbitration (ARB T) via the master controller 50. AXL As a possible implementation of block B110, such arbitration may include determining via the master controller 50 whether to follow the optimal torque request generated at block B106 or to follow the request from the external function and limitations applied in blocks B108 and B109. The weighting of the external requester function ensures that the master controller 50 selects the request from the external function under appropriate conditions (e.g., during a high slip traction control event).

[0088] Therefore, in this case, the torque vector generated by the optimization at block B106 is Instead of being sent to the various torque actuators, requests from an external requestor (e.g., an anti-lock braking system (ABS)) are sent to the various torque actuators. Under operating conditions where the external requestor has a low priority (e.g., under normal driving conditions), block B110 makes an opposite arbitration decision, wherein an optimal torque request is generated at block B106 via the torque vectoring application. Method 100 then proceeds to block B112.

[0089] exist Figure 2 At block B112, the main controller 50 converts the closed-loop control signal (CL→T ACT ) is transmitted to each of the torque actuators (i.e., motor 114E, brake actuator 26, steering actuator 25, differentials 30 and 130, etc.), thereby applying torque vectoring via the front drive axle 119F and / or the second drive axle 119R Thus, the individual torque actuators and associated local controllers respond to these commands with corresponding outputs, whether it is brake pressure, steering response or motor torque, appropriate to the actuator type.

[0090] refer to Figure 3 , shows representative control logic 50L for implementing the above-described method 100 and alternative embodiments within the scope of the present disclosure. For example, the above-described cost optimization function 51 can be implemented as an optimization logic block (OPT) 51B, including (a) an optimization objective 51O and (b) optimization constraints 51C. This optimization block 51B is aware of the allocation of the previous time step to determine the optimal torque allocation for the next time step, that is, the optimization logic block 51B is iterative.

[0091] Optimization objective 510 corresponds to optimization of axle torque requests to satisfy a defined tracking objective function with calibrable weights to balance the priorities between such objectives as described above. Optimization constraints 51C similarly constrain the optimization results, such as by enforcing a calibrated maximum torque as the sum of the individual axle torques, or limiting vehicle velocity as a velocity constraint, or ensuring that axle torque requests satisfy propulsion system constraints (such as battery power limits, wheel slip ratios, etc.).

[0092] Logic block 51B and Figure 1 In response to driver actuation of pedals 22A and / or 22B or rotation of steering wheel 22S, optimization logic block 51B receives a torque request (arrow T REQ ), rate request (arrow N REQ )、lateral speed (V LAT ), the requested yaw rate (ψ REQ ), and from Figure 2 The arbitrated torque of block B110 (arrow T ARB ) and the arbitration rate (N ARB Similarly, the logic block 51B receives the data from the state estimation block 54 (corresponding to Figure 2 The estimated state of the motor vehicle 10 from the block B105 of FIG. 10 and the estimated state of the motor vehicle 10 from the external limit block 55 (corresponding to FIG. Figure 2 External torque and rate limits are determined in blocks B108 and B109 of FIG. Therefore, external requesters have override priority in determining the axle torque request to be arbitrated after optimization of the axle torque request. Therefore, a possible implementation in the optimization scheme includes imposing the external requester with the highest priority or weight as an additional hard constraint on the affected axle.

[0093] From Figure 3 The output of the logic block 51B in FIG. 5 includes the initial axle torque commands (T AXL1 , …,T AXLN ), where in the simplified two-axle embodiment, N = 2; in the case of independent control of the four corners of the motor vehicle 10 used with four different drive axles Figure 1 In the embodiment, up to N = 4. Arbitration blocks 56-1, ..., 56-N are used to implement Figure 2 Block B110 and based on the external axle torque limit (EXT T AXL LIM) to arbitrate the initial axle torque command (T AXL1 , …, T AXLN ). Thereafter, the main controller 50 Figure 2Block B112 transmits closed-loop control signals to the individual torque actuators, where arrows CC1,…, CC N instruct Figure 3 Such control signals in .

[0094] At the output of the local controller (e.g. Figure 1 This strategy can also be employed where a local controller (e.g., MCP-1, MCP-2, MCP-1A, or MCP-1B) is also a command and / or modification to the steering actuator 25. In this case, a given local controller can be programmed with the ability to deliver yaw rate based on the steering angle command and torque vectoring via the motor 114E and / or brake actuator 26.

[0095] As will be appreciated by those skilled in the art from the foregoing disclosure, the present strategy enables closed-loop control of the sum of the individual axle torques to track the total driver torque or rate request in different operating modes. Priority is selected between different control objectives using relative weights of associated costs or penalties, where such costs may be adjusted using calibrated or selectable weights based on driving conditions or operating mode. Within these capabilities, torque dispatch is still subject to propulsion system constraints such as axle torque limitations, e.g., motor limitations and half-axle limitations, battery power limitations, and the like. Thus, the present teachings implement a novel architecture for coordinating the operation of different torque actuators arranged on different drive axles to achieve both longitudinal and lateral vehicle control objectives. In view of the foregoing disclosure, those skilled in the art will readily appreciate these and other benefits.

[0096] The detailed description and the figures or drawings support and describe the present teachings, but the scope of the present teachings is limited only by the claims. Although some best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for practicing the teachings defined in the appended claims. In addition, the present disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A motor vehicle comprising: a first drive axle coupled to the first set of wheels; a second drive axle coupled to a second set of wheels; a plurality of torque actuators each connected to the first drive axle or the second drive axle and configured to transmit a corresponding output torque to the first drive axle and / or the second drive axle, the plurality of torque actuators comprising a plurality of rotary electric machines; and a master controller in communication with the plurality of torque actuators, wherein the master controller is programmed with a calibrated set of constraints and is configured to: receiving a set of vehicle inputs indicative of a total longitudinal motion request and a total lateral motion request for the motor vehicle; calculating a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the set of vehicle inputs; determining, using a cost optimization function, a torque vector for apportioning the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first driven axle and the second driven axle within a calibrated set of constraints; and transmitting a closed-loop control signal to each of the torque actuators to apply the torque vectoring via the first drive axle and the second drive axle, respectively; The motor vehicle further comprises: a mode selection device configured to receive an operator-requested or autonomously-requested mode selection signal, wherein the controller is configured to modify the weights within the cost optimization function in response to the mode selection signal; The master controller is programmed with a tracking function for a desired longitudinal speed, a longitudinal torque request, and a desired yaw rate while constraining the system to a calibrated set of constraints.

2. The motor vehicle according to claim 1, wherein: The plurality of rotary electric machines includes a first electric propulsion motor coupled to the first drive axle and a second electric propulsion motor coupled to the second drive axle.

3. The motor vehicle according to claim 2, wherein: The first drive axle and / or the second drive axle comprises a pair of corresponding half-axles, and wherein the first electric propulsion motor and / or the second electric propulsion motor comprises a pair of corresponding electric propulsion motors each coupled to a corresponding one of the half-axles.

4. The motor vehicle according to claim 1, wherein: The plurality of torque actuators includes one or more brake actuators connected to a respective one of the first drive axle and the second drive axle.

5. The motor vehicle of claim 1, wherein: The constraint set includes hardware constraints, operation constraints and / or external functional constraints.

6. The motor vehicle of claim 1, wherein: The torque vectoring is configured to optimize wheel slip of the first set of wheels and / or the second set of wheels.

7. The motor vehicle of claim 1, wherein: The cost optimization function is configured to optimize the torque vectoring for current tire capacities of the first and second sets of wheels.

8. The motor vehicle of claim 1, wherein: The cost optimization function is configured to optimize the torque vectoring for propulsion efficiency of the motor vehicle.

9. The motor vehicle of claim 1, wherein: The first set of wheels and the second set of wheels are respective front and rear wheels, the first set of wheels and / or the second set of wheels are steerable via respective steering actuators, and the plurality of torque actuators include respective steering actuators.

10. The motor vehicle of claim 1, wherein: The plurality of torque actuators include an internal combustion engine configured to generate an engine output torque including the output torque, and an electronically controlled differential coupled to the internal combustion engine, the electronically controlled differential configured to receive the engine output torque therefrom.

11. A method for controlling motion and torque in a motor vehicle having a first drive axle coupled to a first set of wheels, a second drive axle coupled to a second set of wheels, and a plurality of torque actuators each connected to the first drive axle and / or the second drive axle, the plurality of torque actuators comprising a plurality of rotary electric machines configured to transmit respective output torques to the first drive axle and / or the second drive axle, the method comprising: receiving, via a master controller programmed with a calibrated set of constraints, a set of vehicle inputs indicative of a total longitudinal motion request and a total lateral motion request for the motor vehicle, the set of constraints comprising hardware constraints, operational constraints, and / or external functional constraints; calculating a total longitudinal torque request and / or a total longitudinal velocity request, a yaw rate request, and a lateral velocity request for the motor vehicle using the set of vehicle inputs; determining, using a cost optimization function, a torque vector for apportioning the total longitudinal torque request and / or the total longitudinal velocity request, the yaw rate request, and the lateral velocity request to the first driven axle and the second driven axle within a calibrated set of constraints; and transmitting a closed-loop control signal to each of the torque actuators to apply the torque vectoring via the first drive axle and the second drive axle, respectively; wherein the motor vehicle includes a mode selection device configured to receive an operator-requested or autonomously-requested mode selection signal, the method further comprising: automatically adjusting weights within the cost optimization function via the master controller in response to the mode selection signal; The master controller is programmed with a tracking function for a desired longitudinal speed, a longitudinal torque request, and a desired yaw rate while constraining the system to a calibrated set of constraints.

12. The method according to claim 11, wherein The plurality of rotary electric machines include a first electric propulsion motor coupled to the first drive axle and a second electric propulsion motor coupled to the second drive axle, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting the closed-loop control signal to the first electric propulsion motor and the second electric propulsion motor.

13. The method according to claim 12, wherein: The first drive axle and / or the second drive axle include a pair of corresponding half-axles, and the first electric propulsion motor and / or the second electric propulsion motor include a pair of corresponding electric propulsion motors each coupled to a corresponding one of the half-axles, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting the closed-loop control signal to a pair of corresponding electric propulsion motors.

14. The method according to claim 11, wherein The plurality of torque actuators include one or more brake actuators connected to a respective one of the first drive axle and the second drive axle, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting a closed-loop brake control signal to the one or more brake actuators.

15. The method according to claim 11, wherein Determining a torque vector for dispatching the total longitudinal torque request and / or the total longitudinal velocity request includes optimizing wheel slip of the first set of wheels and / or the second set of wheels via the cost optimization function.

16. The method according to claim 11, wherein Determining a torque vector for dispatching the total longitudinal torque request and / or the total longitudinal speed request includes optimizing the torque vector for current tire capacities of the first and second sets of wheels.

17. The method according to claim 11, wherein Determining a torque vector for dispatching the total longitudinal torque request and / or the total longitudinal velocity request includes optimizing propulsion efficiency of the motor vehicle.

18. The method according to claim 11, wherein The first set of wheels and the second set of wheels are respective front and rear wheels, the first set of wheels and / or the second set of wheels are steerable via respective steering actuators, and the plurality of torque actuators include respective steering actuators, and wherein transmitting the closed-loop control signal to each of the torque actuators includes transmitting a closed-loop steering control signal to the respective steering actuators.

Images