Method for operating a drive system, vehicle, and computer programme product

Abstract

The invention relates to a method for operating a drive system (210) comprising at least one drive (211) of a vehicle (200), in particular a motor vehicle (300). The method comprises: determining a trajectory planning (100) of the vehicle (200), the trajectory planning (100) being designed to take into account at least environment data (110) or driving situation data (120) of the vehicle (200) in order to predict a movement (140) of the vehicle (200); determining a torque requirement (150) which comprises the torques (160) to be provided by a drive system (210) and a start time (170) at which the torques (160) to be provided must be present in order to enable the predicted movement (140) of the vehicle (200); setting a control time (180) at which at least one drive (211) of the drive system (210) of the vehicle (200) is at least activated or deactivated; and activating or deactivating the at least one drive (211) at the set control time (180), the set control time (180) being before the start time (170) of the torque requirement (150). The invention also relates to a vehicle (200) and to a computer programme product.

Description

[0001] Description

[0002] Method for operating a drive system, vehicle and computer program product

[0003] The invention relates to a method for operating a drive system, a vehicle, and a computer program product.

[0004] The demands placed on vehicle drive systems are constantly increasing with advancing development. Drive control, in particular, presents a challenge due to the expanding range of engines such as combustion engines, electric motors, fuel cells, and hybrid engines.

[0005] In addition, there is the progressive automation of the movement (also called trajectory) of the vehicle, especially in motor vehicles, which from level 3 onwards is essentially automatic, so that the person driving does not have to constantly actively monitor the vehicle.

[0006] Even with at least partially automated vehicles, the ride comfort of passengers should not be compromised. In particular, loud noises and sudden movements should be avoided.

[0007] In addition, it is becoming increasingly important that vehicles have the lowest possible energy consumption and a high level of comfort.

[0008] It is an object of the present invention to at least partially remedy the above-mentioned disadvantages known from the prior art. In particular, it is an object of the present invention to provide a method for operating a drive system, a vehicle, and a computer program product that improves the energy consumption of the vehicle and the comfort of the passengers driving and / or being transported, and that can also be manufactured and operated cost-effectively.

[0009] The above object is achieved by a method having the features of claim 1, a vehicle having the features of claim 11, and a computer program product having the features of claim 12. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the vehicle according to the invention and / or the computer program product according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reciprocal reference is or can always be made.

[0010] According to a first aspect of the invention, a method for operating a drive system with at least one drive of a vehicle, in particular a motor vehicle, is provided, comprising:

[0011] - determining a trajectory planning of the vehicle, wherein the trajectory planning is designed to take into account at least environmental data or driving situation data of the vehicle in order to predict a movement of the vehicle, in particular by a control device,

[0012] - determine a torque requirement which is the torque required by a

[0013] drive system and a starting time at which the torques to be provided must be present in order to enable the movement of the vehicle, in particular by a control device,

[0014] - determining a control time at which the at least one drive of the drive system of the vehicle is at least activated or deactivated, in particular by a control device,

[0015] - activating or deactivating at least one drive at the control time, in particular by a control device, wherein the control time is before the start time of the torque request.

[0016] A drive system within the meaning of the invention is to be understood as a system which is designed to provide a force and / or a torque on demand, in particular at a wheel of the vehicle.

[0017] A drive, within the meaning of the invention, is a spatial object that comprises the means for transmitting a force and / or torque, in particular to a wheel of the vehicle. The drive may comprise a motor, which will be explained in more detail below.

[0018] In principle, the vehicle can be any means of transport, in particular a land vehicle, water vehicle, or aircraft. The vehicle can be designed as a motor vehicle (i.e., a motor-driven, non-rail-bound vehicle), in particular as a truck or passenger vehicle. In other words, trajectory planning according to the invention is a particularly short-term determination of the future movement of the vehicle. For example, trajectory planning can be implemented as a data set of four-dimensional vectors, which include a time coordinate in addition to three spatial coordinates. However, other, for example, parametric forms of trajectory planning are also conceivable.

[0019] Environmental data, as defined by the invention, refers to data that is specific to the vehicle's environment. Specific to the vehicle's environment means that the environment causally determines this data. This can be physical data such as temperature, humidity, ambient pressure, etc., or applicable regulations, such as a specification for the maximum permissible speed, a permissible weight, permissible vehicle dimensions, etc.

[0020] Driving situation data within the meaning of the invention, however, is intended to be data that is specific to the vehicle itself. For example, the current speed of the vehicle, the rotational speed of a wheel, the air pressure of a tire, etc. The vehicle data can also include a command from the driver. This command can be detected at least through the position of an accelerator pedal, a brake pedal, or a steering wheel.

[0021] Furthermore, KL-evaluated predictions, especially KL-evaluated ego-vehicle data, which provide predicted acceleration curves, can also be taken into account when determining trajectory planning. This offers the advantage of enabling a particularly accurate prediction of the vehicle's movement and thus also allowing the control timing and start time to be determined with particular precision, thus improving vehicle comfort and fuel consumption.

[0022] In principle, the movement of the vehicle should be understood as any change in its position in space. It can be advantageous, particularly for land vehicles, that the movement corresponds to a movement in the plane of the vehicle's longitudinal and transverse axes (in other words, no change in altitude). This saves computing power and thus manufacturing and operating costs compared to additionally considering altitude.

[0023] A torque request within the meaning of the invention represents a compilation of control data which, when implemented accordingly by the drive system, is suitable for setting the vehicle into the movement predicted by the trajectory planning. Within the meaning of the invention, the term "torques to be provided" means at least one torque, or several torques depending on the design of the drive system, which must be present in order to achieve the movement predicted by the trajectory planning. The torques can in particular be torques. These torques can be applied to one or more wheels of a motor vehicle. It can be provided that a single value is provided. Alternatively or additionally, it can also be provided that the torques to be provided comprise a sequence and / or a progression of torques.

[0024] A starting point in the sense of the invention is understood to be a time specification for an action in relation to a time measurement. Together with the torques to be provided, the predicted movement results from the trajectory planning when the torques to be provided are applied at the starting point.

[0025] It can also be provided that the torque request includes an end time and / or a request duration at which the torques to be provided must be present in order to enable the movement of the vehicle.

[0026] The control time, within the meaning of the invention, is a time specification for an action in relation to a time measurement, in particular to another point in time. The action performed at the control time can be at least the activation or deactivation of at least one drive.

[0027] Activation refers at least to the preparations necessary for the subsequent provision of torque. These preparations may vary depending on the drive. These preparations may involve the application of an excitation field, particularly in the case of an electrically operated drive. These preparations may also include a speed adjustment, which prepares the drive for a clutch operation. Activation may also include a clutch engagement process.

[0028] Deactivation is understood to mean at least the preparations necessary for the subsequent ramping out of the torques, whereby the preparations may vary depending on the drive type. These preparations may involve switching off an excitation field, particularly in the case of an electrically operated drive. Deactivation may also include a disengagement process. It may further be provided that the method includes applying the torques to be provided at the starting time. This enables the vehicle to move according to the trajectory planning.

[0029] Overall, the method according to the invention achieves the advantage that trajectory planning allows the drive system to be activated in a timely manner, so that when the torque demand is met, it is already activated. This prediction prevents unnecessarily early activation of the drive system, as well as uncomfortable, late coupling and excessively frequent changes in the activation status. Early deactivation is also possible, thus saving energy. The method according to the invention thus achieves an optimal spread in terms of efficiency, driving comfort, and responsiveness.

[0030] It is further conceivable in a method according to the invention that a mechanical prestressing of at least the drive or the drive system takes place during activation, wherein in particular the mechanical prestressing corresponds to an expected elasticity of at least the drive system or the drive.

[0031] In other words, the activation can also include a, in particular complete, reduction of application-related free movement spaces (also called slack), in which a mechanical component can move freely against or with another component during operation.

[0032] This has the advantage of reducing the response time at start-up. It also reduces noise and / or load shocks that would occur if the torque to be provided were provided directly by the drive without preloading the drive.

[0033] The expected play can be determined at least by measuring the play or using a model. In particular, the respective positions of the drive's mechanical components can be determined to predict the play and overcome it by preloading. Alternatively, or in addition, the preload can also be increased to a predetermined limit. These options allow the play of the components to be reduced with great precision.

[0034] It is further conceivable in a method according to the invention that the drive system has a separate drive at least for each axle of the vehicle or for each wheel of the vehicle, wherein the activation or deactivation of the drive takes place at least separately for each axle or each wheel.

[0035] In other words, activation and / or deactivation can be provided not only for the entire drive system, but also for each axle or wheel if multiple drives are provided. By individually controlling an axle or wheel, the vehicle's movement can be better and more precisely provided in accordance with the trajectory planning.

[0036] The drive system can be designed to comprise a single drive or a single drive per axle, with the drives of the individual axles being independent of each other. Compared to a single-wheel drive, this offers the advantage of reducing costs and the mass of the wheels. The latter also improves the vehicle's handling.

[0037] Furthermore, it can be provided that the deactivation of the at least one drive occurs in such a way that the at least one drive consumes essentially no energy in the deactivated state. In other words, it can be provided that the energy supply to the at least one drive is interrupted during deactivation. This can achieve the advantage of reducing the operating costs of the vehicle. In the case of an electric drive, it can be provided that the excitation field of an electric motor is completely switched off during deactivation. This also saves energy.

[0038] Furthermore, in a method according to the invention, it can advantageously be provided that the control time is in a temporal range between 10 ms and 1000 ms, in particular in a range between 500 ms and 1000 ms, before the start time. Such a temporal offset between the control and start times offers the advantage of increasing driving comfort, particularly for the occupants in the vehicle, since the response of the drive system is "hidden" in this time window, meaning that no noises or jerking of the vehicle are perceptible.

[0039] Preferably, a method according to the invention can provide for at least the activation or deactivation of the drive to occur without hysteresis. In other words, the method can provide no time limit for reactivating or deactivating the drive. Hysteresis can result in the torque not being available as normally requested, which is perceived by the driver as sluggish response. Furthermore, a method according to the invention can advantageously provide for the at least one drive to have a motor, which is designed in particular as an electric motor. In other words, the at least one drive can have a prime mover designed to provide the power required for the torque. In particular, one motor can be provided per drive, whereby the force and thus the torques can be particularly well controlled.It can also be planned for the entire system to have a single motor or one motor per axle. This offers the advantage over variants with multiple motors that such a vehicle can be manufactured and operated more cost-effectively.

[0040] Furthermore, in a method according to the invention, it can advantageously be provided that at least the environmental data comprise at least a distance to another vehicle or a road boundary, a speed limit, a right-of-way regulation or a road condition, or the driving situation data comprise at least a speed and / or acceleration of the vehicle, a rotational speed of a wheel, a status of the brakes or a voltage of a vehicle battery.

[0041] In other words, the environmental data can include a series of data that are causally determined by the vehicle's surroundings. The vehicle data can be data determined by the vehicle itself and / or the wishes of the occupants in the vehicle. Taking these data into account offers the advantage of particularly precise trajectory planning, which also ensures the vehicle's movement in accordance with the torque requirements specified in the trajectory planning. This results in a particularly high level of driving comfort for the occupants in the vehicle.

[0042] Furthermore, in a method according to the invention, it can advantageously be provided that a sensor system with at least one environment sensor or one driving situation sensor is provided for detecting at least the environment data or the driving situation data.

[0043] In other words, the data considered in trajectory planning can be collected directly from sensors installed on the vehicle. This offers the advantage that the vehicle can ensure reliable trajectory planning even without a connection to a server.

[0044] It can also be provided that at least the environmental data or the driving situation data are provided at least partially by sensors outside the vehicle, in particular by other vehicles, a server, or traffic infrastructure points. By supplementing the relevant data, trajectory planning can be further improved, resulting in overall improved driving comfort.

[0045] Furthermore, in a method according to the invention, it can advantageously be provided that a control device is provided which is designed to carry out at least the determination of a trajectory planning, the determination of a torque requirement, the setting of a control time or the activation or deactivation of the at least one drive at the control time, wherein in particular the control device is connected, in particular by wire, at least to the drive system, the drive or the sensor system.

[0046] In other words, it can be provided that the individual steps of the method according to the invention are carried out by a controller. The controller can in particular be designed as a central processing unit. It can advantageously be provided that, in addition to the method for operating the drive system, the controller also takes over further computing tasks for the operation of the vehicle, which can save costs. The wired connection between the control device and the drive system, the drive or the sensor system also ensures particularly secure data transmission. In addition, a connection, in particular a wireless connection, of the control device to other vehicles, a server, or traffic infrastructure points can be provided.

[0047] According to a further aspect of the invention, there is a vehicle, in particular a motor vehicle, which has a drive system which is designed to be operated according to a method of the preceding claims.

[0048] Thus, a vehicle according to the invention brings with it the same advantages as have already been described in detail with reference to a method according to the invention.

[0049] According to a further aspect of the invention, a computer program product is provided, comprising instructions which cause a control device, in particular a control device according to the invention, to carry out a method according to the invention.

[0050] Thus, a computer program product according to the invention provides the same advantages as those already described in detail with reference to a method according to the invention and / or a vehicle according to the invention. The method for operating a drive system can, in particular, be a computer-implemented method.

[0051] Further advantages, features, and details of the invention will become apparent from the following description, which describes embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. They show schematically:

[0052] Fig. 1: a representation of the method according to the invention,

[0053] Fig. 2: a representation of the temporal course of the moments, and

[0054] Fig. 3: a representation of a vehicle which is constructed according to the

[0055] procedure is operable.

[0056] In the following description of some embodiments of the invention, the same reference numerals are used for the same technical features even in different embodiments.

[0057] Fig. 1 shows the method according to the invention for operating a drive system 210 with at least one drive 211 of a vehicle 200, in particular a motor vehicle 300.The method comprises determining a trajectory planning 100 of the vehicle 200, wherein the trajectory planning 100 is designed to take into account at least environmental data 110 or driving situation data 120 of the vehicle 200 in order to predict a movement 140 of the vehicle 200, determining a torque request 150, which comprises the torques 160 to be provided by a drive system 210 and a starting time 170 at which the torques 160 to be provided must be present in order to enable the movement 140 of the vehicle 200, determining a control time 180 at which the at least one drive 211 of the drive system 210 of the vehicle 200 is at least activated or deactivated, and activating or deactivating the at least one drive 211 at the control time 180, wherein the control time 180 is temporally before the starting time 170 of the torque requirement 150.

[0058] In a vehicle 200 with one or more independently drivable axles 240, a decision can be made based on trajectory planning 100 as to when which drive 211 should be activated. These can be either purely electrically driven axles 240 or hybrid-driven axles 240. The activation and deactivation of a drive 211 can occur mechanically (e.g., closing / opening a clutch) or in another way (e.g., establishing / de-establishing an excitation field).

[0059] Based on the environmental data 110, driving situation data 120, and possibly other input variables, the trajectory planning 100 provides a short-term prediction of the movement, in particular the longitudinal and / or lateral movement, of the vehicle 200. Based on this trajectory planning 100, the decision regarding the activation / deactivation of one or more drives 211 is determined. The prediction allows the drive 211 to be activated in a timely manner so that when the torque request 150 to the drive 211 occurs, it is already activated. The prediction prevents unnecessarily early activation of the drive 211 and excessively frequent changes in the activation status. This achieves an optimal spread in terms of efficiency, driving comfort, and responsiveness.

[0060] The environmental data 110 can include at least a distance to another vehicle or a lane boundary, a speed limit, a right-of-way regulation or a road condition, or the driving situation data 120 can include at least a trajectory planning 100 speed and / or acceleration of the vehicle 200, a rotational speed of a wheel 230, a status of the brakes or a voltage of a vehicle battery.

[0061] As can be seen in Fig. 1, in addition to the environmental data 110 and driving situation data 120, further data, in particular a driver request 130, can be taken into account in the trajectory planning 100.

[0062] The deactivation of the at least one drive 211 can be carried out in such a way that the at least one drive 211 consumes essentially no energy in the deactivated state.

[0063] At least the activation or deactivation of the drive 211 can also be carried out without hysteresis.

[0064] How the method according to the invention for operating a drive system 210 affects the provided torques is illustrated in Fig. 2. After trajectory planning 100 is completed, both the starting time 170 and the control time 180 are fixed, with the control time 180 always being before the starting time 170. Therefore, before the torques 160 to be provided are applied, at least one drive 211 is first activated at the control time 180. During activation, a mechanical preload of at least the drive 211 or the drive system 210 can take place, wherein in particular the mechanical preload corresponds to the elasticities 190 of at least the drive system 210 or the drive 211. This is also the case in the example shown in Fig. 2. Here, the ratio of backlash to provided torque is very small. As a rule, only a small torque is necessary to overcome the backlash.However, the smaller the difference between the clearance 190 and the moment 160, the greater the perceptible effect on the comfort of the vehicle occupants.

[0065] In other words, the use of trajectory planning 100 enables targeted preloading of the drive 211 to overcome driveline slack even before the start of an acceleration process. This further improves the driveline's responsiveness.

[0066] Neither the provision of the 160 torques nor the activation or deactivation need to be gradual, as in the example shown. Other functions, particularly linearly approximated (i.e., differentiable) functions, can also be provided. This results in an even smoother transition for the vehicle occupants.

[0067] Fig. 3 schematically shows a vehicle 200, in particular a motor vehicle 300, which has a drive system 210 which is designed to be able to be operated according to a method according to the invention of the preceding claims.

[0068] The drive system 210 has a separate drive 211 at least per axle 240 of the vehicle 200 or per wheel 230 of the vehicle 200, wherein the activation or deactivation of the drive 211 takes place at least separately per axle 240 or per wheel 230.

[0069] It can also be provided that the at least one drive 211 has a motor 212, which is designed in particular as an electric motor. The motors 212 can be coupled directly to the drive 211, e.g., to a wheel 230 of the vehicle, as in the example shown in Fig. 3, or can be coupled via a transmission to a drive 211, designed in particular as an axle drive.

[0070] Furthermore, it can be provided that a sensor system 260 with at least one environment sensor 261 or one driving situation sensor 262 is provided for detecting at least the environment data 110 or the driving situation data 120. In particular, the environment sensor 261 can be designed as at least one ultrasonic sensor, a radar sensor, a lidar sensor, or a camera. It can also be provided that the driving situation sensor 262 is designed as at least one GPS sensor, a speed sensor, an acceleration sensor, a position sensor, or a voltage sensor.

[0071] As also shown in Fig. 3, a control device 220 can be provided, which is designed to at least carry out the determination of a trajectory planning 100, the determination of a torque request 150, the setting of a control time 180, or the activation or deactivation of at least one drive 211 at the control time 180. In particular, the control device 220 is connected by wire at least to the drive system 210, the drive 211, or the sensor system 260. Furthermore, the control device 220 can also be connected to a driver request input 270. The driver request input 270 can, in particular, comprise at least an accelerator, brake, or clutch pedal, a steering wheel, or other conceivable input instruments.

[0072] The above explanation of the embodiments describes the present invention exclusively by way of examples. Of course, individual features of the embodiments can be freely combined with one another, provided they are technically feasible, without departing from the scope of the present invention.

[0073] List of reference symbols

[0074] Trajectory planning Environmental data Driving situation data Driver request Movement

[0075] Torque requirement Torques Start time Control time Elasticity

[0076] Vehicle drive system drive

[0077] Motor

[0078] Wheel control device

[0079] Axle signal connection sensor system environment sensor driving situation sensor

[0080] Driver request input

[0081] Motor vehicle

Claims

Patent claims 1. Method for operating a drive system (210) with at least one drive (211) of a vehicle (200), in particular a motor vehicle (300), comprising: - Determining a trajectory plan (100) of the vehicle (200), wherein the trajectory plan (100) is designed to take into account at least environmental data (110) or driving situation data (120) of the vehicle (200) in order to predict a movement (140) of the vehicle (200), - Determine a torque requirement (150) which includes the torques (160) to be provided by a drive system (210) and a start time (170) at which the torques (160) to be provided must be available to enable the movement (140) of the vehicle (200), - setting a control point (180) at which at least one drive (211) of the drive system (210) of the vehicle (200) is at least activated or deactivated, - activating or deactivating at least one drive (211) at the control time (180), wherein the control time (180) is prior to the start time (170) of the torque request (150).

2. Method according to claim 1, characterized in that during activation a mechanical preloading of at least the drive (211) or the drive system (210) takes place, wherein in particular the mechanical preload corresponds to an elasticity (190) of at least the drive system (210) or the drive (211).

3. Method according to claim 1 or 2, characterized in that the drive system (210) has a separate drive (211) at least for each axle (240) of the vehicle (200) or for each wheel (230) of the vehicle (200), wherein the activation or deactivation of the drive (211) takes place at least separately for each axle (240) or for each wheel (230). A method according to any one of the preceding claims, characterized in that the deactivation of the at least one drive (211) is carried out such that the at least one drive (211) consumes essentially no energy in the deactivated state. A method according to any one of the preceding claims, characterized in that the control time (180) lies in a time range between 10 ms and 1000 ms, in particular in a range between 500 ms and 1000 ms, before the start time (170). A method according to any one of the preceding claims, characterized in that the activation or deactivation of the drive (211) is hysteresis-free. A method according to any one of the preceding claims, characterized in that the at least one drive (211) comprises a motor (212), which is in particular designed as an electric motor.A method according to any one of the preceding claims, characterized in that at least the environmental data (110) includes at least a distance to another vehicle or a lane boundary, a speed limit, a right-of-way rule, or a road condition, or the driving situation data (120) includes at least a speed and / or acceleration of the vehicle (200), a rotational speed of a wheel (230), a brake status, or a vehicle battery voltage. A method according to any one of the preceding claims, characterized in that a sensor system (260) with at least one environmental sensor (261) or a driving situation sensor (262) is provided for detecting at least the environmental data (110) or the driving situation data (120). A method according to any of the preceding claims, characterized in that a control device (220) is provided which is configured to perform at least the determination of a trajectory plan (100), the determination of a torque request (150), the setting of a control point (180), or the activation or deactivation of at least one drive (211) at the control point (180), wherein, in particular, the control device (220) is wired to at least the drive system (210), the drive (211), or the sensor system (260). A vehicle (200), in particular a motor vehicle (300), which has a drive system (210) configured to be operated according to a method of the preceding claims. A computer program product comprising instructions that cause a control device (220), in particular according to claim 10, to execute a method according to any one of claims 1 to 10.

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