System and method for coordinating and controlling drive and / or brake torques in a motor vehicle

Abstract

The invention relates to a system and a method for coordinating drive and / or braking torques in a motor vehicle with selected interfaces for communication between processing modules.

Description

[0001] The present invention relates to a system for coordinating drive and / or brake torques in a motor vehicle, a motor vehicle with such a system, and a method for operating such a motor vehicle. State of the art

[0002] Electrically or partially electrically powered vehicles are becoming increasingly important, and the control architecture of such vehicles is also changing compared to conventional vehicles. This is partly due to the fact that electric drive motors can perform functions that were previously only available to hydraulic braking systems. However, a braking torque can also be generated at selected wheels of a vehicle through the regenerative operation of an electric drive motor. To optimize the coordination of all possible actuators in the vehicle, it is also necessary to consider that the same functions can be provided by different actuators, such as when a braking request is implemented using an electric drive motor and, in particular, a hydraulic or electromechanical friction braking system.This makes optimized coordination and control of signals and requirements, up to their implementation, increasingly important. Systems are also appearing on the market that employ a central processing module or control unit, which handles key aspects of the momentary requirements or their implementation. The subsequent control units or processing modules in the cascade then process the signal or requirement provided by the central control unit until it is implemented by the respective actuator.

[0003] A system is already known from German patent application DE 10 2023 201 427 A1, comprising a first processing module designed to receive a request for a drive or brake torque of the motor vehicle, to process the received request according to specifications for the motor vehicle, and to distribute the processed request to several axles of the motor vehicle; several second processing modules designed to each receive a request for a drive or brake torque for an axle from the first processing module, to each process the request according to specifications for the corresponding axle, and to distribute the processed request as accelerating or decelerating wheel torques to the wheels of the respective axle; and several third processing modules designed toEach of the second processing modules receives a request for a drive or brake torque for a wheel from one of the second processing modules and processes the request according to the specifications of the corresponding wheel of the axle. Several fourth processing modules are each designed to receive a processed request for a drive or brake torque for a wheel from one of the third processing modules, process the request according to the specifications for a controllable actuator, and provide a corresponding control signal to the controllable actuator. To ensure smooth communication between the processing modules, the aforementioned document proposes that the processing modules be coupled to each other via predefined interfaces. Disclosure of the invention

[0004] The present invention has the advantage that coordination and control are based on selected interfaces. Thus, the invention provides that, through the advantageous choice of interfaces, safe and reliable operation of the motor vehicle is ensured at all times. According to the invention, this is advantageously achieved by the system with the features of claim 1 and the method with the features of claim 6.

[0005] According to the invention, at least the interfaces between the first processing module and the second processing modules are designed to transmit requirements in a force-based manner. The advantage of a force-based requirement is its independence from the distribution of the requirement across axles and wheels. Unlike a torque interface, force-based communication does not require consideration of differences in wheel radii when distributing force between, for example, the front and rear axles. This advantageously enables the system to be used centrally on many different platforms with different actuators and / or second, third, and / or fourth processing modules. Force-based communication means that the respective requirement is transmitted and received as a force value, in particular as a braking force or drive force value.

[0006] The interfaces between the second and third processing modules and / or between the third and fourth processing modules are particularly preferred for transmitting requirements based on torque and / or speed. These torque and speed interfaces allow for the advantageous integration of subsequent processing modules in the cascade. This is especially beneficial for vehicle dynamics functions. Torque-based communication means that the respective requirement is converted into a torque, specifically drive torque, braking torque, or deceleration torque, and transmitted and received accordingly.Speed-based communication means that the respective request is converted into a speed, in particular the target speed of a wheel or axle of the motor vehicle, and transmitted and received.

[0007] According to an alternative embodiment of the invention, it is preferably provided that the interfaces between the second and third processing modules and / or between the third and fourth processing modules are configured to transmit requirements in a force-based manner. Of course, a mixed design is also possible, such that preferably some interfaces at a functional or hierarchical level of the system are configured to be force-based only, or torque-based only, or speed-based only, while other interfaces at the same functional or hierarchical level are preferably configured for force-based communication.

[0008] According to a preferred embodiment of the invention, the processing modules are configured to receive and / or send force-based, torque-based, and / or speed-based requirements. In particular, the first processing module is configured to send force-based requirements. At least the second processing modules are particularly preferably configured to receive force-based requirements and to send at least torque- and speed-based requirements, optionally or additionally also force-based requirements. Preferably, the third processing modules are configured to receive and send at least torque- and speed-based requirements. Preferably, the fourth processing modules are configured at least to receive and implement torque- and speed-based requirements.Overall, the advantageous design of the system results in an advantageous arbitration cascade across the different functional levels.

[0009] The motor vehicle according to the invention, with the features of claim 5, is characterized by the system according to the invention. This results in the advantages already mentioned.

[0010] The method according to the invention, with the features of claim 6, is characterized in that at least the first processing module communicates requirements with the second processing modules in a force-based manner. This results in the advantages already mentioned above.

[0011] Preferably, the second and third processing modules and / or the third and fourth processing modules communicate with each other based on torque and / or speed. This also results in the advantages already mentioned above.

[0012] Preferably, the second processing modules and the third processing modules and / or the third processing modules and the fourth processing modules communicate with each other in a force-based manner.

[0013] Further advantages and preferred features and combinations of features will become apparent in particular from the foregoing and from the claims. The invention will now be explained in more detail with reference to the drawing. To this end, we show... Fig. 1 a simplified representation of a motor vehicle with an advantageous system for coordinating drive and / or braking torques, and Fig. 2. A schematic diagram to illustrate the system.

[0014] Fig. Figure 1 shows a schematic representation of a motor vehicle 1 with an advantageous system 10 for coordinating and controlling drive and brake torques according to an exemplary embodiment. The motor vehicle 1 is optionally a fully or at least partially electrically driven vehicle 1. For this purpose, the motor vehicle has an electric drive system in which electrical energy, for example from a traction battery, is supplied by means of a power converter to at least one electric machine, or in the case of two electric machines M1, M2, in order to drive the respective electric machine M1, M2. The respective electric machine M1, M2 can also be operated in generator mode, whereby the kinetic energy of the vehicle is converted into electrical energy by means of the respective electric machine M1, M2, which is stored, in particular, in an electrical storage device of the motor vehicle 1.

[0015] According to the present embodiment, each axle A1, A2 of the motor vehicle 1 is equipped with an electric machine M1, M2. According to an alternative embodiment, only one of the two axles A1, A2 has an electric machine M1, M2. According to a further embodiment, each wheel R1 to R4 of the motor vehicle 1 has its own separate drive machine.

[0016] According to the present embodiment, two wheels R1, R2 and R3, R4 respectively are arranged on each axle A1, A2. The distribution of the drive and braking torques to the individual wheels R1 to R4 can be arbitrary and is carried out by the advantageous system 10. Furthermore, according to the present embodiment, each of the wheels R1 to R4 is assigned a brake actuator B1 to B4, which may be, for example, a hydraulic or electromechanical brake actuator.

[0017] System 10 is in Fig. Figure 1 is a highly simplified representation. In reality, it consists of several control units, which represent processing modules that together coordinate and control the brake actuators B1-B4 and the drive motors M1, M2. System 10 is designed to control the drive motors M1, M2 and the brake actuators B1 to B4 in a coordinated manner, depending on a detected request from the driver or vehicle controller for accelerating or decelerating torque of the vehicle 1, in order to implement the request in the best possible way.

[0018] For example, if System 10 detects a braking request, it coordinates the activation of the necessary actuators, specifically brake actuators B1-B4 and drive motors M1 and M2, taking into account current vehicle parameters and specifications. System 10 is specifically designed to distribute and / or limit the drive torque or braking torque request across the individual actuators M1, M2, and B1 to B4, ensuring that predefined parameters are not exceeded and / or that vehicle stability requirements are met.

[0019] Fig.Figure 2 shows a simplified representation of the advantageous system for coordinating and controlling the drive and brake torques of the motor vehicle 1. The system 10 comprises a first processing module 11, which processes the requested drive and brake torques at a functional level for the entire motor vehicle 1 or distributes them accordingly to the next, underlying functional level. The processing module is, in particular, a central control unit of the motor vehicle 1. The subsequent functional level is, in this case, the functional level of the individual axles A1 and A2. The first processing module 11 checks, for example, whether a maximum permissible value is exceeded by the detected request or whether a minimum permissible value is undercut.For example, if a drive torque is requested that cannot be realized according to the current vehicle parameters—because, for instance, the electrical energy storage system cannot provide the required power or the maximum power has to be simulated for thermal reasons—then the request is advantageously limited at the global vehicle level by processing module 11. Similarly, double braking torques can also be limited at the global vehicle level by processing module 11.

[0020] The first processing module, 11, then distributes the request to the individual axles A1 and A2 of the vehicle 1. Different approaches to this distribution can be applied, depending on boundary conditions and / or driving situations. For example, the distribution can be based on a driving or operating mode selected by the driver, or on current weather and / or road conditions. The torque distribution can also be distributed between axles A1 and A2 within predefined ranges to optimize wear on the tires and / or actuators. Vehicle parameters such as current speed, longitudinal or lateral acceleration, and similar factors can also be taken into account.

[0021] The processing module 11 is designed to communicate the distribution to the axes A1, A2 in a force-based manner, so that force-based values ​​are passed on to the subsequent functional level.

[0022] System 10 further comprises several second processing modules 12, in particular second control units, which are configured to receive and process the force-based requirements provided by the first processing module 11 and, if necessary, to apply limitations or the like for each axis A1, A2. For this purpose, the second processing modules 12 communicate with the first processing module 11 via one or more first interfaces S1, which are configured for force-based communication. In this context, the interface is understood to be, in particular, the communication link between the two processing modules involved. If an interface is configured in a specific way, this means that the two processing modules have corresponding provisions for the selected interface that fulfill the interface requirement, such as force-based communication.For the first interface S1, this means that the first processing module is configured to output a request as a force value, which may first be calculated by the first processing module 11 depending on the detected driving request from a driver or driving controller, and that the respective second processing module is configured to receive and process the force value. For example, if an electric drive torque is requested for an axle A1, A2 that cannot currently be realized by the electrical system of the vehicle 1, the corresponding second processing module 12 can limit the request accordingly. The respective processing module 12 is specifically configured to also take into account the aforementioned framework conditions and / or driver specifications.Furthermore, the second processing module 12 is designed to distribute the drive or brake torques requested for the respective axles A1, A2 in a suitable manner to the respective wheels R1 to R4 of the respective axle A1, A2.

[0023] The resulting desired drive and braking torques for the individual wheels R1 to R4 are then transmitted, in particular, to third processing modules 13. Communication between the second processing modules 12 and the third processing modules 13 takes place via one or more interfaces S2, which are configured for torque- and speed-based transmission of the requirements.

[0024] The third processing modules 13, in particular control units, are designed to individually process the requested drive or brake torques for each wheel R1 to R4 and, if necessary, limit them. Here, too, the vehicle parameters already mentioned above can be taken into account. Optionally, the respective processing module 13 also considers information about the coefficient of friction between the respective tire of wheel R1 to R4 and the road surface.

[0025] The resulting drive or brake torques for the individual wheels R1 to R4 are then advantageously transmitted or sent by the respective third processing module 13 to at least one fourth processing module 14. The third processing modules 13 are coupled to the fourth processing modules 14 via a third interface S3, or each of these third interfaces S3 is configured for torque- and speed-based communication of the respective requirement.

[0026] The fourth processing modules 14, in particular control units, are specifically designed to receive the processed request for a drive or brake torque for a wheel R1 to R4 from one of the third processing modules 13 via interface S3 and to process the request according to the specifications for a controllable actuator, for example, brake actuator B1 to B4 or drive motor M1, M2, and to send or provide the corresponding control signal to the controllable actuator. In particular, the processing modules 14 are designed to adjust the received drive or brake torques to ensure that a maximum specified slip between the wheels R1 to R4 and the road surface is not exceeded. Of course, other specifications, in particular the vehicle parameters mentioned above, can also be taken into account.

[0027] This hierarchical approach, in which the requirement for a drive or brake torque is divided into several functional levels according to processing modules 11 to 14, ensures a structure that allows for efficient processing of the requested torques. In each functional level, the requested torque is processed individually, particularly to maintain vehicle stability. The modular, hierarchical structure with defined interfaces S1 to S3 enables simple and efficient adaptation at each functional level. The standardized interfaces S1 to S3, which are defined by specific "communication languages," ensure advantageous coupling between the hierarchical levels. The advantages of the selected interfaces will be explained in more detail below:

[0028] The example of a tractor clearly illustrates the importance of standardized interfaces S1 to S3 for a uniform and modular architecture. Depending on the chosen interface or communication language, the wheel radius of wheels R1 to R4 has a significant impact on the force distribution between the front and rear axles. Due to the different wheel radii on a tractor—the front axle typically has a much smaller radius compared to the rear axle, which has a much larger radius—different braking forces and decelerations result, even with identical total vehicle moment requirements. The advantageously standardized interfaces S1 to S3 for the respective functional levels ensure that the requirements from the arbitration cascade are distributed and specified independently of the vehicle.Furthermore, the S1 to S3 interfaces enable easy integration of actuators, speed-controlled actuation for specific driving dynamics functions and safeguarding against axle and wheel slip.

[0029] The standardized interfaces allow functions to be developed on a single control unit or processing module by different suppliers. Furthermore, the system enables the control units themselves to originate from different suppliers and still be easily integrated into the overall System 10 as processing modules. This System 10 utilizes interfaces that consider force-based function requirements at the vehicle level (interface S1), torque-based requirements at the axle and wheel level (interfaces S2, S3), and allow for the extension of function requirements at the axle and wheel level to include slip control (interfaces S2, S3). The system also enables distribution requirements to axles A1 and A2, as well as wheels R1 to R4, and between electrical and hydraulic requirements.Using the advantageous interfaces S1 to S3, controls for longitudinal vehicle guidance, longitudinal stability, lateral guidance and lateral stability, and vertical stability can be connected to the arbitration cascade.

[0030] The standardized interfaces S1 to S3 enable an advantageous distribution of the vehicle's desired torque between the front and rear axles, as well as between the friction actuators of the brakes B1 to B4 and the electric actuators or electric machines M1 and M2. At the axle level, the functions participating in the arbitration can request an increase or decrease in torque. At the wheel level, the axle torque can be redistributed between the left and right sides of the vehicle to the wheels R1 to R4, and the respective wheel torque can be individually increased or decreased.

[0031] The use of the advantageous interfaces S1 to S3 enables the use of multiple actuators in a centralized architecture. Furthermore, System 10 allows for the coupling of the participating systems and the abstraction of actuator specifics. Preferably, the selection of suitable interfaces takes into account the respective permissible or desired latency between the functional levels.

[0032] The advantageous force-based communication from processing module 11 to processing modules 12 has the benefit of being independent of the distribution of requirements across the axles. Unlike a torque interface, differences in wheel radius do not need to be considered when distributing forces between the front and rear axles. The force-based communication eliminates the need to take wheel radii into account. The force-based interface also proves advantageous when a function is distributed across different control units or processing modules, or when there is separate functional responsibility between different processing modules from different manufacturers.

[0033] The advantageous S2 and S3 interfaces, which require or enable torque- and / or speed-based communication, allow for the beneficial integration of the underlying actuators. Speed-controlled actuation of the actuators is particularly advantageous for vehicle dynamics functions that require a non-linear tire force characteristic.

[0034] An interface for slip or wheel / axle speed would require an agreed-upon set of dynamic, non-measurable vehicle parameters on both sides (requester and receiver), which could lead to control errors during operation. The use of speed interfaces S2 and S3 ensures high robustness with regard to state and parameter uncertainties, even with varying vehicle speeds, body slip, or differing tire radii; it also provides robustness with regard to network latency. For example, if the central processing module 11 assumes a tire radius that differs by 1 cm from that of processing module 13, which is directly assigned to one of the brakes, a target slip of 8% on central processing module 11 results in a deviation of 39% on processing module 13. Therefore, the use of a speed interface proves advantageous.The impact of differing vehicle states and / or parameters between the central control unit and the brake control unit is reduced. The disadvantage of latency can be mitigated. For lateral and traction control, axle dynamics are typically limited; extrapolation measures can be used to account for network latency. For example, a conversion layer can be implemented at the input of processing module 13, which internally converts the input signal into slip. This cancels out any deviations in state or parameters. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 201 427 A1

[0003]

Claims

[1] System (10) for coordinating and controlling drive and / or brake torques in a motor vehicle (1), comprising: a. a first processing module (11) designed to receive a request for a drive or brake torque of the motor vehicle (1), to process the received request in accordance with specifications for the vehicle (1) and to distribute the processed request to several axles (A1, A2) of the motor vehicle (1); b. several second processing modules (12) designed to each receive a request for a drive or brake torque for an axle (A1, A2) from the first processing module (11), to each process the requests according to the specifications of the corresponding axle and to distribute the processed request as accelerating or decelerating wheel torques to the wheels (R1-R4) of the respective axle (A1, A2); c. several third processing modules (13) designed to each receive a request for a drive or brake torque for a wheel (R1-R4) from one of the second processing modules (12) and to each process the requests according to the specifications of the corresponding wheel (R1-R4) of the axle (A1, A2); d. several fourth processing modules (14), each designed to receive a processed request for a drive or brake torque for a wheel (R1-R4) from one of the third processing modules (13), to process the requirements according to specifications for an actuator (M1,M2, B1-B4) of the motor vehicle (1) to be controlled and to provide a corresponding control signal at the actuator (M1,M2, B1-B4) to be controlled, e. wherein the processing modules are communicatively coupled to each other via predetermined interfaces (S1-S3), f. characterized by, that at least the interface (S1) between the first processing module (11) and the second processing modules (12) is designed to transmit the requirements in a force-based manner. [2] System according to claim 1, characterized by , that at least the interfaces (S2,S3) between the second processing modules (12) and the third processing modules (13), and / or between the third processing modules (13) and the fourth processing modules (14) are designed to transmit the requirements based on torque and / or speed. [3] System according to any one of the preceding claims, characterized by , that the interfaces (S2,S3) between the second processing modules (12) and the third processing modules (13), and / or between the third processing modules (13) and the fourth processing modules (14) are designed to transmit the requirements force-based. [4] System according to any one of the preceding claims, characterized by , that the processing modules (11,12,13,14) are designed to receive and / or send force-based requests, torque-based requests and / or speed-based requests. [5] Motor vehicle (1) comprising a drive system and a braking system and a system (10) for coordinating and controlling drive and / or braking torques depending on a request from a driver or driving controller of the motor vehicle (1), characterized by the design of the system (10) according to one of claims 1 to 4. [6] Method for operating a motor vehicle (1) according to claim 5 with a system (10) for coordinating and controlling drive and / or braking torques of the motor vehicle (1), wherein the system (10) comprises: a. a first processing module (11) designed to receive a request for a drive or brake torque of the motor vehicle (1), to process the received request in accordance with specifications for the motor vehicle (1) and to distribute the processed request to several axles (A1, A2) of the motor vehicle (1); b. several second processing modules (12) designed to each receive a request for a drive or brake torque for an axle (A1, A2) from the first processing module (11), to each process the requests according to the specifications of the corresponding axle (A1, A2) and to distribute the processed request as accelerating or decelerating wheel torques to the wheels (R1-R4) of the respective axle (A1, A2); c. several third processing modules (13) designed to each receive a request for a drive or brake torque for a wheel (R1-R4) from one of the second processing modules (12) and to each process the requests according to specifications of the corresponding wheel (R1-R4) of the axle (A1, A2); d. several fourth processing modules (14), each designed to receive a processed request for a drive or brake torque for a wheel (R1-R4) from one of the third processing modules (13), to process the requests according to specifications for an actuator to be controlled and to provide a corresponding control signal to the actuator to be controlled, e. where the processing modules communicate with each other via predetermined interfaces (S1-S3), f. characterized by, that at least the first processing module (11) communicates with the second processing modules (12) requirements through a first or first interface (S1) in a force-based manner. [7] Method according to claim 6, characterized by , that at least the second processing modules (12) and the third processing modules (13), and / or the third processing modules (13) and the fourth processing modules (14) communicate torque- and speed-based requirements through second or third interfaces (S2,S3). [8] Method according to any one of the preceding claims, characterized by , that the second processing modules (12) and the third processing modules (13), and / or the third processing modules (13) and the fourth processing modules (14) communicate requirements through second or third interfaces (S2,S3) force-based. [9] Method according to any one of the preceding claims, characterized by, that the processing modules (11-14) are trained to receive and / or send force-based requests.

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