Method for controlling an actuator of a vehicle

Abstract

To provide a method for improving the comfort for a vehicle operator and reducing the entire energy consumption during the operation.SOLUTION: The present disclosure relates to a method for controlling at least one actuator 104 of a vehicle. The actuator 104 is configured to apply a torque on at least one wheel of the vehicle. The applied torque is determined by a control function associated with a control bandwidth. The method comprises the steps of: configuring the control function to control the applied torque to reduce a difference between a first parameter value related to a current rotational speed of the wheel and a second parameter value related to a target rotational speed of the wheel; obtaining data indicative of a current operating condition of the vehicle; setting the control bandwidth of the control function in dependence of the current operating condition of the vehicle; and controlling the actuator 104 using the control function.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for controlling at least one actuator of a vehicle. The present disclosure also relates to a method implemented in an actuator control system, a method implemented in a vehicle dynamics management system, an actuator control system, and a vehicle dynamics management system. Furthermore, the present disclosure relates to a control signal representing an instruction to be executed by the actuator control system. The present disclosure is applicable to electric vehicles. The present disclosure is primarily directed to vehicles in the form of trucks that use electric machines for propulsion, but may also be applicable to other types of vehicles. [Background technology]

[0002] In the field of vehicles, particularly light, medium and heavy vehicles commonly referred to as lorries, there is a continuous development of various control functionalities of the vehicles, which are intended in particular to improve the ease of driving the vehicle, the comfort for the driver and the safety during operation.

[0003] CN104228609 relates to a wheel speed control method. In particular, a module calculates an actual vehicle speed by using the speeds of four wheels. The module then calculates a difference between the actual vehicle speed and a target vehicle speed and inputs the difference value to a controller. The controller outputs a target torque for the drive motor. Therefore, the drive torque is obtained through feedback adaptive adjustment, and the accelerator pedal is not directly related to the motor torque, so the driver does not need to constantly adjust the accelerator pedal during driving.

[0004] Although CN104228609 presents an attempt to improve vehicle operation, it still needs further improvement, particularly with respect to operator comfort. Therefore, it is desirable to improve comfort for the vehicle operator while also reducing overall energy consumption during operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] CN104228609 Summary of the Invention

[0006] It is an object of the present disclosure to at least partially overcome the above-mentioned drawbacks. According to a first aspect, there is provided a method for controlling at least one actuator of a vehicle, the actuator being configured to apply a torque to at least one wheel of the vehicle, the applied torque being determined by a control function associated with a control bandwidth, the method comprising the steps of configuring the control function to control the applied torque so as to reduce a difference between a first parameter value related to a current rotational speed of the wheel and a second parameter value related to a target rotational speed of the wheel, obtaining data indicative of a current operating condition of the vehicle, setting the control bandwidth of the control function in response to the current operating condition of the vehicle, and controlling the actuator using the control function.

[0007] A control function is understood as an operation functionality configured to apply a torque to at least one actuator. Depending on the control bandwidth, the torque can be applied with various response times depending on the current operating conditions. According to one example, as also described below, a decreased bandwidth can be associated with an increased torque response time to the actuator. Thus, torque is applied more rapidly with an increased bandwidth.

[0008] Furthermore, the value for the current rotational speed of the wheel and the value for the target rotational speed of the wheel are interpreted as values ​​that can relate to both the rotational wheel speed and the wheel slip, i.e. the difference between the wheel speed relative to the ground and the actual wheel speed. In the latter case, the first parameter is therefore the current wheel slip of the wheel and the second parameter is the target wheel slip of the wheel.

[0009] The advantage is that the bandwidth is controlled based on the current operating conditions, resulting in a rapid torque response when required and a lower, gentler torque response in other situations. This improves comfort during operation and reduces the overall energy consumption of the vehicle, as rapid, energy-intensive maneuvers are only performed when required. Furthermore, the ability to change settings more flexibly provides more flexibility in optimizing vehicle control overall.

[0010] Additionally, the control function obtains parameters related to the rotational speed of the wheels. A common approach to requesting a specific tire force at a wheel is to use torque control at the actuator level based on a torque request sent from a higher-level control function. However, the latency involved in communication between different control functions, for example over a Controller Area Network (CAN) bus, significantly limits slip control performance. Thus, speed-based control is advantageous compared to, for example, torque-based control. In particular, for electric machines, locally implemented speed-based control of wheel slip is more rapid compared to centralized torque control, primarily due to the CAN message cycle time.

[0011] As described in more detail below, the method can be preferably implemented using a vehicle dynamics management system and an actuator control system. When implementing such a vehicle dynamics management system and actuator control system, the bandwidth can be controlled in several different ways. For example, the vehicle dynamics management system is configured to transmit a control signal to the actuator control system that includes a target bandwidth and data related to the vehicle's operating conditions. Thus, the target bandwidth is set / determined by the vehicle dynamics management system. Based on the target bandwidth, the actuator control system determines a control bandwidth to achieve the target bandwidth based on various parameters.

[0012] According to another example, the vehicle dynamics management system is configured to determine the control bandwidth itself based on current operating conditions and transmit a control signal indicative of the determined control bandwidth to the actuator control system, which then controls the actuators using the control bandwidth received from the vehicle dynamics management system.

[0013] According to yet another example, the actuator control system may be provided with a plurality of predetermined bandwidth setting parameters, and the vehicle dynamics management system is then configured to determine which bandwidth parameter setting is most suitable based on current operating conditions, and transmit a control signal to the actuator control system to use the determined bandwidth setting parameter when controlling the actuator.

[0014] Further details of control functions and control bandwidth are described below with respect to other aspects of the disclosure.

[0015] According to a second aspect, there is provided a method implemented in an actuator control system for controlling at least one actuator to apply torque to at least one wheel of a vehicle, the actuator control system comprising a control function, the torque to be applied being determined by the control function associated with a control bandwidth, the method comprising the steps of determining a first parameter value related to a current rotational speed of the wheel, configuring the control function to control the torque to be applied so as to reduce a difference between the first parameter value and a second parameter value related to a target rotational speed of the wheel, obtaining data indicative of a current operating condition of the vehicle, setting a control bandwidth of the control function in response to the current operating condition of the vehicle, and controlling the actuator using the control function.

[0016] Data indicative of current operating conditions may be obtained from, preferably by receiving control signals from, the higher level vehicle dynamics management system described above.

[0017] According to an example embodiment, the control function may be configured to control the velocity of the actuator.

[0018] As noted above, actuator speed control is particularly advantageous when an electric machine is used to propel a vehicle because speed-based control is more rapid than torque control. Speed-based control is also more accurate in controlling slip than torque-based control and is more robust to disturbances such as changes in friction between the wheel surface and the road surface, potholes, etc.

[0019] According to example embodiments, increased bandwidth of the control function may be associated with increased torque response to the actuator, which translates to decreased torque response time.

[0020] According to an example embodiment, the control bandwidth of a control function is controlled using a predetermined set of actuator feedback gains, with each feedback gain associated with a particular operating condition of the vehicle. The feedback gains are interpreted as parameters that characterize the actuator response. Thus, the "aggressiveness" of the torque response is based on the predetermined set of gains, with larger feedback gain values ​​producing a more rapid torque response, i.e., higher bandwidth control behavior. For example, larger gains are preferably provided for operating conditions that require a rapid torque response.

[0021] According to an example embodiment, the control function may be a PID controller.

[0022] PID controllers, also known as proportional-integral-derivative controllers, are particularly useful for controlling actuators using feedback gains. PID controllers calculate an error value as the difference between a first and second parameter value, which can be advantageous for making rapid corrections. As an example, if current operating conditions require a rapid response, the proportional and integer terms of the PID controller are increased compared to current operating conditions that require a more gradual torque response.

[0023] According to an example embodiment, the control function may be a proportional controller, and the method further includes obtaining a signal indicating a target bandwidth for the control function, and configuring the control function using a proportional parameter related to the target bandwidth and the current operating conditions of the vehicle.

[0024] A proportional controller is understood as a control function that simply controls the actuator by a proportional value of a target bandwidth, which is therefore preferably a proportional parameter of the difference between a first parameter value related to the current rotation speed and a second parameter value related to the target rotation speed.

[0025] Further advantages and features of the second embodiment are largely similar to those described above with respect to the first embodiment.

[0026] According to a third aspect, there is provided a method implemented in a vehicle dynamics management system of a vehicle, the vehicle dynamics management system being connectable to an actuator control system for communication of control signals therebetween, the method comprising the steps of obtaining a current speed of the vehicle, determining a current operating condition of the vehicle, and transmitting a control signal to the actuator control system, the control signal, when executed by the actuator control system, representing an instruction to a control function of the actuator control system to apply torque to at least one wheel of the vehicle to reduce a difference between a first parameter value related to a current rotational speed of the wheel based on the current speed of the vehicle and a second parameter value related to a target rotational speed of the wheel, in relation to a control bandwidth, the control bandwidth being determinable depending on the current operating condition of the vehicle.

[0027] The current speed of the vehicle may be the current wheel speed of the vehicle's wheels, or simply the speed of the vehicle. The vehicle speed may preferably be obtained from a speed sensor or the like, as well as from an advanced driver assistance system (ADAS). Accordingly, the vehicle dynamics management system transmits higher-level vehicle parameters to an actuator control system, which determines specific parameters of the wheels based on control signals received from the vehicle dynamics management system. For example, the vehicle dynamics management system transmits a signal containing data indicative of the vehicle's speed, and the actuator control system converts this vehicle speed into a parameter value related to the rotational speed of the wheels. The actuator control system preferably incorporates current drivetrain conditions when determining the rotational speed of the wheels. Such drivetrain conditions preferably include the current gear, the engaged / disengaged status of one or more clutches, etc.

[0028] Thus, the vehicle dynamics management system issues control signals that enable the actuator control system to appropriately control the actuators, as described above in relation to the second aspect.

[0029] According to an example embodiment, the method further includes determining a target velocity of the vehicle based on current operating conditions, the target rotational velocity of the wheels being based on the target velocity of the vehicle.

[0030] Therefore, the target speed is determined by the higher-level vehicle motion management system.

[0031] According to an example embodiment, the method further includes determining a desired operating performance of the vehicle based on current operating conditions, and the control bandwidth is further determinable as a function of the desired operating performance of the vehicle.

[0032] The desired handling performance relates, for example, to a favorable driving experience and / or driving comfort for the driver.

[0033] According to an example embodiment, the method comprises the steps of determining a target bandwidth and transmitting a control signal including the determined target bandwidth, wherein the control bandwidth is further determinable as a function of the target bandwidth. The control signal thus indicates the determined target bandwidth. Therefore, the control signal provided to the actuator control system preferably indicates the target bandwidth that is obtained by the actuator control system as the control bandwidth when configuring the control function preferably using the above-mentioned proportionality parameter.

[0034] According to example embodiments, the current operating conditions of the vehicle may be based on at least one of the current vehicle conditions and the current road conditions the vehicle is traveling in. Thus, the current operating conditions may be obtained from certain parameters of the vehicle, such as, for example, a loaded or unloaded vehicle, and / or based on road conditions, such as, for example, slippery or slippery road conditions.

[0035] According to an example embodiment, the current operating conditions may be at least one of the current vehicle mass, the gradient of the road on which the vehicle is traveling, the vehicle speed, the level of friction between the vehicle's wheels and the road surface, and the current tire stiffness.

[0036] These operating conditions may be determined, for example, based on sensor signal data or by computation based on sensor data inputs, etc. An advantage is that the control bandwidth may be manipulated based on several parameters and factors of the vehicle and its environment.

[0037] According to a fourth aspect, there is provided an actuator control system for a vehicle configured to control at least an actuator to apply torque to at least one wheel of the vehicle, the actuator control system comprising a control function, the applied torque being determined by the control function associated with a control bandwidth, the actuator control system being configured to: determine a first parameter value related to a current rotational speed of the wheel; configure the control function to control the applied torque to reduce a difference between the first parameter value and a second parameter value related to a target rotational speed of the wheel; obtain data indicative of current operating conditions of the vehicle; set a control bandwidth of the control function in response to the current operating conditions of the vehicle; and control the actuator using the control function.

[0038] The effects and features of the fourth embodiment are largely similar to those described above with respect to the first, second and third embodiments, particularly the second embodiment.

[0039] According to a fifth aspect, there is provided a vehicle dynamics management system for a vehicle, connectable to an actuator control system for communication of control signals therebetween, and configured to obtain a current speed of the vehicle, determine a current operating condition of the vehicle, and transmit a control signal to the actuator control system, the control signal representing, when executed by the actuator control system, an instruction to cause a control function of the actuator control system to apply torque to at least one wheel of the vehicle to reduce a difference between a first parameter value related to a current rotational speed of the wheel based on the current speed of the vehicle and a second parameter value related to a target rotational speed of the wheel, in association with a control bandwidth, wherein the control bandwidth is determined in response to the current operating condition of the vehicle.

[0040] The effects and features of the fifth embodiment are largely similar to those described above with respect to the first, second and third embodiments, especially the third embodiment.

[0041] According to a sixth aspect, there is provided a control signal representing an instruction to be executed by an actuator control system of a vehicle, the control signal including a vehicle speed component that enables the actuator control system to determine a current rotational speed of a wheel, and a vehicle operating condition component that represents an instruction, when executed by the actuator control system, to a control function of the actuator control system to apply torque to at least one wheel of the vehicle in association with a control bandwidth to reduce a difference between a first parameter value relating to a current rotational speed of the wheel based on a current speed of the vehicle and a second parameter value relating to a target rotational speed of the wheel, the control bandwidth being determinable depending on a current operating condition of the vehicle.

[0042] The vehicle speed component may include data indicative of a target vehicle speed that enables the actuator control system to determine a target rotational speed for the actuator.

[0043] According to a seventh aspect, there is provided a computer program comprising program code means for, when executed on a computer, performing the steps of any one of the above embodiments relating to the first, second and third aspects.

[0044] According to an eighth aspect, there is provided a computer readable medium storing a computer program comprising program means for, when executed on a computer, performing the steps of any one of the above embodiments relating to the first, second and third aspects.

[0045] The advantages and features of the sixth, seventh, and eighth aspects are largely similar to those described above with respect to the remaining aspects of the present disclosure.

[0046] Further features and advantages will become apparent from a consideration of the appended claims and the following description. Those skilled in the art will appreciate that different features can be combined to create embodiments other than those described below without departing from the scope of the present disclosure.

[0047] The above, as well as additional objects, features, and advantages, will be better understood through the following illustrative and non-limiting detailed description of illustrative embodiments. [Brief explanation of the drawings]

[0048] [Figure 1] FIG. 1 is a side view illustrating an example embodiment of a vehicle in the form of a lorry. [Figure 2] FIG. 1 is a schematic diagram of a vehicle dynamics management system and actuator control system, according to an example embodiment. [Figure 3] 1 is a graph illustrating an example embodiment of a model showing the relationship between wheel slip and tire force; [Figure 4] 2 is a flowchart of a method for controlling actuators of the vehicle in FIG. 1 according to an example embodiment. [Figure 5] 3 is a flowchart of a method implemented in the actuator control system of FIG. 2, according to an example embodiment. [Figure 6] 3 is a flowchart of a method implemented in the vehicle dynamics management system of FIG. 2, according to an example embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0049] The present disclosure will now be described more fully with reference to the accompanying drawings, in which illustrative embodiments are shown. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided for the purpose of thoroughness and completeness of the description. Like reference numerals refer to like elements throughout the description.

[0050] With particular reference to FIG. 1 , a vehicle 100 in the form of a truck is shown. The vehicle includes a plurality of wheels 102, each with a respective actuator 104. While the embodiment shown in FIG. 1 illustrates an actuator for each wheel 102, it should be readily understood that, for example, a set of wheels 102 may be arranged without an actuator 104. Furthermore, the actuator 104 is preferably an actuator for generating torque on each wheel of the vehicle, or on both wheels of an axle. The actuator may be, for example, an electric machine 106 configured to apply a longitudinal wheel force to the wheels of the vehicle 100, as shown in FIG. 3 and described further below. Such an electric machine may therefore be adapted to generate propulsion torque as well as be placed in a regenerative braking mode to charge a battery (not shown) or other energy storage system of the vehicle 100. The electric machine may also generate braking torque without storing energy. For example, a brake resistor or the like may be used to dissipate excess energy from the electric machine during braking.

[0051] Further, each actuator 104 is connected to a respective actuator control system 300 arranged to control the operation of the actuator 104. The actuator control system 300 is preferably a distributed actuator control system 300, although a centralized implementation is also possible. It will further be understood that portions of the motion assistance system may be implemented in processing circuitry remote from the vehicle, such as a remote server 1000 accessible from the vehicle via a wireless connection. Still further, each actuator control system 300 is connected to the vehicle motion management system 200 of the vehicle 100 via a data bus communication arrangement 114, which may be either wired, wireless, or both wired and wireless. This allows control signals to be transmitted between the vehicle motion management system 200 and the actuator control system 300. The vehicle motion management system 200 and the actuator control system 300 are described in further detail below with reference to FIG. 2.

[0052] The vehicle dynamics management system 200 and the actuator control system 300 may include a microprocessor, a microcontroller, a programmable digital signal processor, or other programmable device. The system may also or instead include an application-specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. If the system includes a programmable device such as a microprocessor, a microcontroller, or a programmable digital signal processor, the processor may further include computer-executable code for controlling the operation of the programmable device.

[0053] 2, which is a schematic diagram of a vehicle motion management system 200 and an actuator control system 300, according to an example embodiment. As such, the vehicle motion management system 200 and the actuator control system 300 form part of a vehicle motion system 500. The comprehensive vehicle control system may be implemented in one or more vehicle unit computers (VUCs). The VUCs may be configured to execute a vehicle control method organized according to a layered functional architecture, with some functions included in a higher-level traffic situation management (TSM) domain and some other functions included in a lower-level vehicle motion management (VMM) domain.

[0054] 2 schematically illustrates functionality for controlling one or more wheels by an example actuator control system (MSD), such as friction braking and propulsion devices. Friction braking and propulsion devices are examples of wheel torque-generating devices, also sometimes referred to as actuators, that may be controlled by one or more actuator control systems. Control is based on measurement data obtained, for example, from wheel speed sensors and other vehicle state sensors, such as radar sensors, lidar sensors, and vision-based sensors, such as camera sensors and infrared detectors. Other example torque-generating actuator control systems that may be controlled according to the principles discussed herein include engine retarders and power steering devices.

[0055] The MSD control unit may be located on one or more actuators. For example, it is not uncommon for an MSD control unit to be arranged to control both wheels on a given axle, e.g., via a differential.

[0056] The TSM function plans a maneuver over a time horizon, such as 10 seconds. This time frame corresponds, for example, to the time it takes a vehicle to negotiate a curve. The vehicle maneuvers planned and executed by the TSM may be associated with acceleration and curvature profiles that represent the desired vehicle speed and the turn resulting from the given maneuver. The TSM receives the desired acceleration profile a from the VMM function, which distributes forces to satisfy the requests from the TSM in a safe and robust manner. req and curvature profile c req continuously demands.

[0057] Acceleration and curvature profiles may also be obtained from the driver of the heavy vehicle via conventional control input devices such as the steering wheel, accelerator pedal, and brake pedal.

[0058] The VMM function operates for a planning period of approximately 1 second, and the acceleration profile a req and curvature profile c reqinto control commands for controlling vehicle motion functions actuated by different MSDs of vehicle 100, which report possible outputs to the VMM, which in turn are used as constraints in vehicle control. The VMM function performs vehicle state or motion prediction, i.e., the VMM function frequently, but not always, interfaces with the MSDs to continuously measure vehicle state, including position, velocity, acceleration, and articulation angles of different units in the vehicle's coordinated motion, by monitoring its operation using various sensors located on vehicle 100.

[0059] The result of the motion prediction, i.e., the predicted vehicle state, is to move the vehicle 100 along the requested acceleration and curvature profile a req , c req The required global force vector is input to a force generation module which determines the global forces required for the different vehicle units to move according to the required force vector. The required global force vector is input to an MSD adjustment function which distributes wheel forces and adjusts other MSDs such as steering and suspension. The adjusted MSDs then apply the desired lateral force F to the vehicle units. y and longitudinal force F x and the required moment M z are given together, and the desired motion is obtained by the coordinated operation of the vehicles.

[0060] By determining the motion of the vehicle unit using, for example, a global positioning system, vision-based sensors, wheel speed sensors, radar sensors, and / or lidar sensors, and transforming this motion of the vehicle unit into the local coordinate system of a given wheel (e.g., in terms of longitudinal and lateral velocity components), the motion of the vehicle unit in the wheel's reference coordinate system can be compared with data obtained from wheel speed sensors located in connection with the wheels to accurately predict wheel slip.

[0061] The tire model, discussed in more detail below in connection with FIG. 3, is based on the desired longitudinal tire force F xand wheel slip. Wheel slip is related to the difference between the rotational speed of the wheel and its velocity relative to the ground. Wheel speed is the rotational speed of the wheel, given in units of, for example, revolutions per minute (rpm) or angular velocity converted to radians per second (rad / s) or degrees per second (deg / s).

[0062] As used herein, a tire model is a model of wheel behavior that describes the wheel forces generated in the longitudinal direction (in the direction of rotation) and / or the lateral direction (perpendicular to the longitudinal direction) as a function of wheel slip. The fundamentals of tire models are described in "Tire and vehicle dynamics", Elsevier Ltd. 2012, ISBN 978-0-08-097016-5, Hans Pacejka. See, for example, Chapter 7, which discusses the relationship between wheel slip and longitudinal forces.

[0063] In summary, the VMM function manages both the force generation and the MSD adjustment, i.e., it determines what forces are required by the vehicle units to achieve a request from the TSM function, e.g., to accelerate the vehicle according to a requested acceleration profile requested by the TSM and / or to perform a certain curvilinear movement by the vehicle, also requested by the TSM. The forces may be, for example, the yaw moment M z , longitudinal force F x and lateral force F y , as well as different types of torque applied to different wheels.

[0064] The VMM 200 is arranged as a higher-level control system, while the MSD 300 is arranged as a lower-level control system. The higher-level VMM 200 is therefore configured to determine various parameters in the vehicle / wheel domain, i.e., based on global vehicle conditions such as vehicle speed, as described below. On the other hand, the lower-level MSD 300 is configured to determine parameters for actuators connected to the wheels. The lower-level MSD converts signals received from the higher-level VMM to the actuator domain, taking into account, for example, gear ratios, driveline inertia, etc.

[0065] Thus, and as described below, the vehicle dynamics management system and the actuator control system are control systems of the vehicle, each configured to perform various control functions to control the operation of the vehicle, in particular to control wheel operation. The vehicle dynamics management system is configured to receive and determine higher-level wheel parameters, as described above, i.e., the vehicle dynamics management system determines, for example, the desired speed in a more generalized form, while the actuator control system is configured to convert the parameters received from the vehicle dynamics management system into appropriate parameters for the actuators.

[0066] By way of non-limiting example, vehicle dynamics management system 200 comprises vehicle condition module 202, vehicle speed module 204, and, optionally, bandwidth module 280. Vehicle dynamics management system 200 is further configured to receive vehicle operational signals 502 containing data utilized by vehicle dynamics management system 200 and its various modules 202, 204, 280. For example, vehicle operational signals 502 provided to vehicle dynamics management system 200 may include data in the form of signals indicative of the vehicle's current environment, current traffic conditions, vehicle weight parameters, such as whether the vehicle is loaded, unloaded, or partially loaded. Vehicle dynamics management system 200 can also receive other signals indicative of specific vehicle conditions, such as current vehicle operating conditions, as described below. Modules may be formed by more modules than those shown in FIG. 2 , but configured to transmit communication signals between each other, i.e., different modules are configured to communicate with each other, as will become apparent from the following disclosure. It should be readily understood that the vehicle condition module 202, the vehicle speed module 204, and the bandwidth module 280 are illustrated as separate components for illustrative purposes only. The vehicle motion management system 200 may, of course, itself comprise various control functions that perform the operations briefly described below.

[0067] The functional operation of the vehicle dynamics management system 200 is described below. In particular, the vehicle dynamics management system 200 is configured to receive an input signal 502 having information regarding the vehicle's current speed. Furthermore, the vehicle condition module 202 is configured to determine the current operating condition of the vehicle 100. The current operating condition may include data indicative of, for example, the wheel friction level between the vehicle's wheels and the road surface, the vehicle's current weight (i.e., whether the vehicle is unladen, laden, or partially laden), and / or the topology of the road on which the vehicle is currently traveling. Thus, the vehicle's current operating condition is based on at least one of the current vehicle condition and the current road condition on which the vehicle is traveling. Thus, various operating conditions may be determined by the vehicle dynamics management system 200 as individual conditions or as a single condition by combining different operating conditions into a comprehensive operating condition. The vehicle's current operating condition can be determined by receiving data from appropriate sensors, which are then transmitted to the vehicle dynamics management system 200. Additionally, the bandwidth module 280 is configured, in the example embodiment, to determine the bandwidth transmitted to the actuator control system 300 .

[0068] Vehicle dynamics management system 200 is further configured to transmit a control signal 550 to actuator control system 300. Control signal 550 includes data indicative of the current operating conditions of vehicle 100 and the current speed of the vehicle. Control signal 550 also preferably includes data indicative of a control bandwidth, which is described in further detail below.

[0069] The actuator control system 300 preferably includes a wheel speed module 302 and a control function 304. The wheel speed module 302 is configured to determine a first parameter value related to the current rotational speed of the wheel 102. The first parameter may be either the rotational wheel speed of the wheel 102 or the current wheel slip of the wheel 102. The first parameter value related to the current rotational speed of the wheel 102 is based on the current vehicle speed received from the vehicle motion management system 200. Thus, the speed module 302 converts the high-level vehicle speed value into a parameter expressed in a wheel-by-wheel coordinate system (not shown).

[0070] With respect to wheel slip, the characteristics of longitudinal tire force and associated wheel slip are shown in FIG. 3. Accordingly, FIG. 3 illustrates a tire model 350 showing the relationship between calculated longitudinal wheel slip and predicted longitudinal wheel force values. Tire model 450 also optionally shows the relationship of the maximum obtainable lateral wheel force to a given longitudinal wheel slip. Model 450 also shows the resulting lateral wheel force for a given longitudinal wheel slip for a predetermined lateral slip angle of the tire. Vertical axis 340 shows the tire force generated between the wheel 102 and the surface supporting the wheel 102, and horizontal axis 330 shows the longitudinal wheel slip of the wheel 102.

[0071] 2, the actuator control system 300 is also configured to determine a target rotational speed of the wheels 102. The target rotational speed of the wheels may be determined based on data from the control signal 550, whereby the control signal 550 includes data regarding a desired vehicle speed. The actuator control system 300 is provided to convert such vehicle speed into a parameter expressed in a wheel-by-wheel coordinate system.

[0072] Further, the actuator control system 300 is configured to determine the torque to be applied to the actuator 104. In particular, the actuator control system 300 is provided to configure a control function 304 to control the torque applied by the actuator 104 to reduce the difference between the current rotational speed and the target rotational speed. The actuator control system 300 is further configured to use, by the control function, a control bandwidth received from the vehicle dynamics management system. The actuator control system 300 may also be configured to set the control bandwidth for the control function 304 based on the current operating conditions received from the vehicle dynamics management system 200. The actuator 104 is thereby controlled to apply the torque using the control function. The control function is preferably configured to control the speed of the actuator.

[0073] Thus, torque is applied by the actuator using different control bandwidths depending on the current operating conditions of the vehicle 100. Thus, torque is applied rapidly when the current operating conditions require it, or more gently when the current operating conditions do not require such a rapid torque response. Furthermore, the vehicle control system now has the option to set not only the desired target value for control but also the control bandwidth at which control is implemented, thereby providing greater freedom in implementing vehicle motion control. A large control bandwidth typically implies a more rapid response to changes in road gradient, friction, etc. A smaller bandwidth implies a slower response to changes in operating conditions, but on the other hand, a smaller bandwidth provides better noise suppression.

[0074] According to an example embodiment, the control bandwidth of the control function is controlled using a predetermined set of feedback gains for the actuators, and the control function is preferably a PID controller.

[0075] Additionally, the control function may optionally include a feedforward component, which may be used, for example, as input data for the selection of the feedback gain of the controller.

[0076] By way of non-limiting example, the following equations (1)-(4) may be used when calculating the predicted torque demand for an actuator, which is preferably used to set the P, I, and / or D gains of a PID controller.

[0077]

number

[0078] Reference is now made to Figure 4, which is a flowchart of a method for controlling actuators of the vehicle of Figure 1, according to an example embodiment. The various operations performed by the method described in connection with Figure 4 are not limited to being performed by any one particular vehicle motion management system 200 or actuator control system 300, but rather serve as a comprehensive description of the functional operations of the present disclosure.

[0079] The method is configured to control the actuator 104 shown in Figure 1. The actuator is configured to apply a torque to the wheel to which the actuator is connected, as described above. The applied torque is determined by a control function associated with a control bandwidth. Thus, the control function of the method of Figure 4 can form part of either the vehicle motion management system 200 or the actuator control system 300. The control function is configured to control the applied torque (S1) to reduce the difference between the current rotational speed of the wheel and the target rotational speed of the wheel, as described in further detail above.

[0080] Additionally, data indicative of the current operating conditions of the vehicle is also obtained (S2). The control bandwidth of the control function is then set (S3) according to the current operating conditions of the vehicle 100, whereby the actuators are controlled using the control function (S4).

[0081] The vehicle dynamics management system 200 and actuator control system 300 described above are also configured to implement a method of operation, according to an example embodiment. The operation of the vehicle dynamics management system 200 and actuator control system 300 is described above, and reference is now made to Figures 5 and 6 for a summary.

[0082] Reference is first made to Figure 5, which is a flowchart of a method implemented in the actuator control system of Figure 2, according to an example embodiment. As described above with respect to Figure 2, the actuator control system 300 comprises a control bandwidth and associated control functionality. The actuator control system 300 is configured to determine (S10) a first parameter value related to a current rotational speed of the wheels 102 of the vehicle 100. As described above, the first parameter value is either the rotational speed of the wheels or a current wheel slip of the wheels. The control functionality of the actuator control system 300 is then configured to be controlled to apply torque to the actuator 104 to reduce the difference between the first parameter value and a second parameter value related to a target rotational speed of the wheels 102 (S20).

[0083] Furthermore, the actuator control system 300 and / or the vehicle dynamics management system 200 are configured to acquire (S30) data indicative of a current operating condition. Thus, the current operating condition is received by the actuator control system 300 from the vehicle dynamics management system 200 or transmitted to the vehicle dynamics management system 200 by a vehicle operating signal 502. Depending on the current operating condition, a control bandwidth is set (40), whereby the actuator control system 300 controls the actuator using the control function (S50).

[0084] Finally, reference is made to Figure 6, which is a flowchart of a method implemented in the vehicle dynamics management system of Figure 2, according to an example embodiment. As described above, the vehicle dynamics management system 200 obtains the current speed of the vehicle 100 (S100). The current speed of the vehicle 100 may be obtained, for example, by receiving a signal from a speed sensor or similar device on the vehicle 100. The vehicle dynamics management system 200 further determines the current operating conditions of the vehicle 100 (S200) and transmits a control signal 550 to the actuator control system 300 (S300).

[0085] The control signal 550 transmitted from the vehicle motion management system to the actuator control system represents an instruction that, when executed by the actuator control system 300, causes the control function 304 of the actuator control system to apply torque to at least one wheel of the vehicle to reduce the difference between a first parameter value related to a current rotational speed of the wheel based on the current speed of the vehicle and a second parameter value related to a target rotational speed of the wheel, in association with a control bandwidth, the control bandwidth being determinable depending on the current operating conditions of the vehicle.

[0086] The target rotational speed of the wheels 102 may be based on a target vehicle speed determined by the vehicle dynamics management system 200. The vehicle dynamics management system 200 may also be configured to determine a desired handling performance, such as a desirable driving experience and / or driving comfort for a driver, so that the vehicle dynamics management system 200 can transmit the desired handling performance as an input parameter for the actuator control system when setting the control bandwidth.

[0087] Thus, the methods described in connection with Figures 5 and 6 are adapted to work in conjunction with one another.

[0088] It should be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings, but rather, those skilled in the art will recognize that many variations and modifications may be made within the scope of the appended claims.

Claims

1. 1. A method for controlling at least one actuator (104) of a vehicle (100), the actuator (104) being configured to apply a torque to at least one wheel (102) of the vehicle (100), the applied torque being determined by a control function associated with a control bandwidth; - configuring (S1) said control function to control said applied torque so as to reduce the difference between a first parameter value related to the current rotational speed of said wheel (102) and a second parameter value related to a target rotational speed of said wheel (102); - (S2) obtaining data indicative of current operating conditions of the vehicle, the current operating conditions including at least one of the following, or a combination thereof: road friction level, vehicle mass, road gradient, and tire stiffness; - setting (S3) the control bandwidth of the control functions depending on the current operating conditions of the vehicle (100); - controlling (S4) said actuator (104) using said control function; A method for providing the above.

2. 1. A method implemented in an actuator control system (300) for controlling at least one actuator (104) to apply a torque to at least one wheel (102) of a vehicle (100), the actuator control system (300) comprising a control function, the applied torque being determined by the control function in conjunction with a control bandwidth; - determining (S10) a first parameter value related to the current rotational speed of said wheels (102); - configuring (S20) said control function to control said applied torque so as to reduce the difference between said first parameter value and a second parameter value related to a target rotational speed of said wheels (102); - obtaining data indicative of current operating conditions of the vehicle (S30), the current operating conditions including at least one of the following, or a combination thereof: road friction level, vehicle mass, road gradient, and tire stiffness; - setting (S40) the control bandwidth of the control function depending on the current operating conditions of the vehicle; - controlling said actuator using said control function (S50); A method for providing the above.

3. The method of claim 2 , wherein the control function is configured to control a velocity of the actuator (104).

4. 4. The method of claim 2 or 3, wherein an increased bandwidth of the control function is associated with an increased torque response of the actuator.

5. 5. The method of claim 2, wherein the control bandwidth of the control function is controlled using a predetermined set of feedback gains for the actuators, each feedback gain being associated with a particular operating condition of the vehicle.

6. The method of claim 5 , wherein the control function is a PID controller.

7. the control function is a proportional controller; The method comprises: obtaining a signal indicating a target bandwidth for said control function; - configuring said control function using proportionality parameters related to said target bandwidth and said current operating conditions of said vehicle; 7. The method of claim 2, further comprising:

8. 1. A method implemented in a vehicle dynamics management system (200) of a vehicle (100), the vehicle dynamics management system being connectable to an actuator control system (300) for communication of control signals therebetween; - obtaining (S100) the current speed of said vehicle (100); - determining (S200) current operating conditions of the vehicle (100), the current operating conditions including at least one of the following, or a combination thereof: road friction level, vehicle mass, road gradient, and tire stiffness; - transmitting a control signal (550) to the actuator control system (S300); Equipped with The control signal, when executed by the actuator control system, represents a command to apply torque to at least one wheel of the vehicle by a control function of the actuator control system to reduce a difference between a first parameter value relating to a current rotational speed of a wheel based on the current speed of the vehicle and a second parameter value relating to a target rotational speed of the wheel, in association with a control bandwidth, the control bandwidth being determinable depending on the current operating conditions of the vehicle.

9. determining a target speed for the vehicle based on the current operating conditions; The method of claim 8 , wherein the target rotational speed of the wheel is based on the target speed of the vehicle.

10. determining a desired operating performance of the vehicle based on the current operating conditions; The method of claim 8 or 9, wherein the control bandwidth is further determinable as a function of the desired handling performance of the vehicle.

11. determining a desired bandwidth; transmitting said control signal including said determined target bandwidth; further comprising The method according to any one of claims 8 to 10, wherein the control bandwidth is further determinable depending on the target bandwidth.

12. 12. The method of any one of claims 8 to 11, wherein the current operating condition of the vehicle is based on at least one of a current vehicle condition and a current road condition on which the vehicle is traveling.

13. 1. An actuator control system (300) for a vehicle (100), configured to control at least an actuator (104) to apply a torque to at least one wheel of the vehicle, the actuator control system comprising a control function, the applied torque being determined by the control function associated with a control bandwidth, the actuator control system comprising: - determining a first parameter value related to the current rotational speed of said wheel; - configuring said control function to control said applied torque so as to reduce the difference between said first parameter value and a second parameter value related to a target rotational speed of said wheel; - obtaining data indicative of current operating conditions of the vehicle, the current operating conditions including at least one of a road friction level, a vehicle mass, a road gradient, and tire stiffness, or a combination thereof; - setting the control bandwidth of the control function in response to the current operating conditions of the vehicle; - using said control function to control said actuator An actuator control system (300) configured as follows.

14. a vehicle dynamics management system (200) for a vehicle (100), connectable to an actuator control system (300) for communication of control signals (550) therebetween; - obtaining the current speed of said vehicle; determining current operating conditions of the vehicle, the current operating conditions including at least one of a road friction level, a vehicle mass, a road gradient, and tire stiffness, or a combination thereof; - transmitting control signals to said actuator control system It is configured as follows: the control signal, when executed by the actuator control system, represents, in conjunction with a control bandwidth, a command to apply torque by a control function of the actuator control system to at least one wheel of the vehicle to reduce a difference between a first parameter value related to a current rotational speed of a wheel based on the current speed of the vehicle and a second parameter value related to a target rotational speed of the wheel; A vehicle dynamics management system (200) wherein the control bandwidth is determined in response to the current operating conditions of the vehicle.

15. A control signal (550) representing an instruction to be executed by an actuator control system (300) of a vehicle (100), comprising: a vehicle speed component that enables said actuator control system (300) to determine the current rotational speed of the wheels (102); a vehicle operation condition component representing, when executed by the actuator control system (300), a command to apply torque to at least one wheel of the vehicle by a control function of the actuator control system in association with a control bandwidth, in order to reduce a difference between a first parameter value relating to a current rotational speed of the wheel based on a current speed of the vehicle and a second parameter value relating to a target rotational speed of the wheel; wherein the vehicle operating condition component includes data indicative of at least one of a road friction level, a vehicle mass, a road gradient, and a tire stiffness, or a combination thereof; A control signal (550), wherein the control bandwidth is determinable as a function of the current operating conditions of the vehicle.

16. A computer program comprising program code means for carrying out the steps of any one of claims 1 to 14 when said computer program is run on a computer.

17. A computer readable medium storing a computer program comprising program means for performing the steps of any one of claims 1 to 14 when the program is run on a computer.

Images