EP4313729A1 - Système et procédé permettant d'actionner un système de direction électromécanique d'un véhicule - Google Patents

Système et procédé permettant d'actionner un système de direction électromécanique d'un véhicule

Info

Publication number
EP4313729A1
EP4313729A1 EP22716328.4A EP22716328A EP4313729A1 EP 4313729 A1 EP4313729 A1 EP 4313729A1 EP 22716328 A EP22716328 A EP 22716328A EP 4313729 A1 EP4313729 A1 EP 4313729A1
Authority
EP
European Patent Office
Prior art keywords
information
steering
driver
torque
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22716328.4A
Other languages
German (de)
English (en)
Inventor
Stefan Feick
Philipp Kessler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Continental Autonomous Mobility Germany GmbH
Original Assignee
Continental Autonomous Mobility Germany GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Continental Autonomous Mobility Germany GmbH filed Critical Continental Autonomous Mobility Germany GmbH
Publication of EP4313729A1 publication Critical patent/EP4313729A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D15/00—Steering not otherwise provided for
    • B62D15/02—Steering position indicators ; Steering position determination; Steering aids
    • B62D15/025—Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/008—Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D1/00—Steering controls, i.e. means for initiating a change of direction of the vehicle
    • B62D1/24—Steering controls, i.e. means for initiating a change of direction of the vehicle not vehicle-mounted
    • B62D1/28—Steering controls, i.e. means for initiating a change of direction of the vehicle not vehicle-mounted non-mechanical, e.g. following a line or other known markers
    • B62D1/286—Systems for interrupting non-mechanical steering due to driver intervention
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input

Definitions

  • the invention relates to a system and a method for controlling an electromechanical steering system of a vehicle.
  • Electromechanical steering systems for vehicles also EPS: Electric Power Steering
  • EPS Electric Power Steering
  • a program-controlled electric servomotor supports and superimposes the driver's steering movements by transferring forces to the steering mechanism.
  • Lane-guided driver assistance systems use captured environmental information to control the vehicle laterally and longitudinally along a planned trajectory.
  • the electromechanical steering is used as an actuator for lateral vehicle guidance, which receives suitable control information from a trajectory follower controller.
  • systems with a first interface variant are known in which the vehicle's lateral dynamics are influenced by an additive superimposition of torque values with the motor torque of the control motor of the electromechanical steering.
  • systems with a second interface variant are known in which the vehicle's lateral dynamics are controlled by specifying a target steering angle.
  • a steering angle controller is implemented on the electromechanical steering control unit.
  • the main design goal for driver assistance systems is to achieve high control quality in lane guidance. Simultaneously striving for a high degree of steering comfort when oversteering by the driver often leads to a conflict of objectives. Under “oversteering” is understood here that the driver at the Steering device performs a steering movement that deviates from the steering movement specified by the driver assistance system.
  • driver torque can increase continuously up to a value that corresponds to the level of the safety barrier that is due to the limitation of the engine torque of the servomotor of the electromechanical steering to ensure oversteerability by the driver.
  • This increase in the driver's torque is due to the fact that the driver's actions are interpreted as a disturbance torque directly acting on the angle control loop and also as a disturbance variable for the trajectory following control loop due to the resulting change in vehicle alignment.
  • This disturbance by the driver is then corrected using the dynamics of the overall disturbance transfer function of the lateral control.
  • the higher the dynamics of the overall disturbance transfer function the faster the counter-torque for the driver increases.
  • the counter-torque for the driver rises all the higher in absolute terms, the higher the direct component amplification of the overall disturbance transfer function.
  • the driver assistance system works against the driver without taking into account the driving situation and impedes him by the driver having to apply an additional steering torque in order to meet the specification of the driver assistance system, which is currently pursuing a different management goal , to overrule.
  • the above-described effects in cooperative driving ie when the driver interacts with the driver assistance system, lead to reduced driving comfort and thus to less acceptance of the driver assistance function.
  • the invention relates to a system for controlling an electromechanical steering system of a vehicle.
  • the vehicle includes a driver assistance system that is designed to generate a first piece of steering control information.
  • the system has a control unit with at least one first regulator unit.
  • the control unit includes a first interface that is designed to receive driver moment information.
  • the control unit includes at least one second interface, which is designed to receive at least one piece of adjustment information that is dependent on the driving condition and/or the driving situation.
  • First and second adjustment information is preferably provided via the second interface. At least one of the items of adjustment information is dependent on the driving status or driving situation.
  • the control unit is configured to provide second steering control information that is obtained from the
  • Driver moment information and the at least one adjustment information is dependent. Furthermore, the system is designed to provide the steering system of the vehicle with modified steering control information based on the first and second steering control information, based on the one steering movement is carried out on the electromechanical steering system.
  • modified steering control information means that either the modified steering control information itself or a variable derived from it, which is formed, for example, by the transfer function of a safety barrier, is used to initiate steering movements on the electromechanical steering system.
  • the technical advantage of the system according to the invention is that the driver torque that the driver feels on the steering device during cooperative driving can be adjusted as a function of the driving condition or driving situation, resulting in a driving behavior that feels natural to the driver.
  • the driver torque that the driver feels on the steering device during cooperative driving can be adjusted as a function of the driving condition or driving situation, resulting in a driving behavior that feels natural to the driver.
  • the driver assistance system is it made more difficult to override the specification of the driver assistance system in such a way that the driver is signaled that it is better, depending on the driving situation, to comply with the specification of the driver assistance system.
  • the first steering control information item is angle information, torque information for the servomotor of the electromechanical steering system, or information that is proportional to the torque of the servomotor of the electromechanical steering system.
  • the driver assistance system thus controls the electromechanical steering either based on setpoint steering angle information or a setpoint torque specification, and this setpoint steering angle information or setpoint torque specification is converted into the modified steering control information depending on the driver's influence through the second steering control information.
  • the system can be used both in an interface variant with an angle interface and in an interface variant with a torque interface.
  • first adjustment information is a driver torque threshold value.
  • the control unit is designed to generate second steering control information, which is a modification of the first steering control information provided by the driver assistance system, when the amount of driver moment information is above the driver moment threshold value causes.
  • second steering control information is a modification of the first steering control information provided by the driver assistance system, when the amount of driver moment information is above the driver moment threshold value causes.
  • second adjustment information is oversteering stiffness information, which is a measure of the steering resistance that the driver has to overcome at the steering device in order to oversteer the steering behavior specified by the driver assistance system.
  • Oversteering stiffness information forms information similar to a variable spring constant of a spring, via which a force that has to be overcome in order to compress the spring can be adjusted.
  • the oversteering stiffness information indicates how sluggish the steering behavior that is specified by the driver assistance system can be influenced by the driver. By changing the oversteering stiffness information, it is thus possible to set, depending on the situation, how the driver's torque on the steering device must be in order to bring about a predetermined steering movement of the electromechanical steering system.
  • the control unit is designed to adapt the control behavior of the first control unit of the control unit based on the oversteering stiffness information.
  • At least one amplification factor of the first controller unit is preferably adjusted as a function of the oversteering stiffness information.
  • a function can be provided that maps the required degree of oversteering stiffness to the at least one amplification factor. There is preferably a reciprocal dependency such that a higher oversteering stiffness is converted to a lower control loop gain and vice versa.
  • Oversteering stiffness information done.
  • a function can also be provided here be that maps the required level of oversteering stiffness to the at least one cut-off frequency.
  • the control unit is designed to receive first and second adjustment information, with either one of the two adjustment information having a fixed value and the other adjustment information having a value dependent on the driving status or driving situation, or the first and second adjustment information being both dependent on the driving status or driving situation.
  • the steering behavior of the driver assistance function can be designed as a function of the driving status and driving situation in such a way that the most natural possible cooperative driving behavior is achieved.
  • the control unit is designed such that the first controller unit receives a torque difference that is zero when the amount of driver torque information is less than or equal to the driver torque threshold value and has an amount of driver torque information reduced by the driver torque threshold value as soon as the amount of driver torque information reaches the driver torque threshold value exceeds. In this way it can be achieved that the specification of the steering assistance system is only influenced by the driver when he applies a significant torque to the steering device.
  • the first controller unit has an absolute value characteristic that falls monotonically above a limit frequency.
  • Such a control behavior is advantageous for a cooperative driving behavior, since vibrations in the steering wheel, for example, as a result of the control circuit created by the negative feedback of the driver's moment, can thereby be effectively avoided.
  • the first controller unit has a control behavior in accordance with a PT1 controller.
  • This type of controller is advantageously suitable for the interactive control of the vehicle through influences by the driver and the driver assistance system.
  • the first controller unit has a control behavior such that the modification of the first steering control information item by the second steering control information item reduces the torque difference supplied to the first controller unit as an input variable. This achieves a control behavior of the system such that the driver assistance function is increasingly adjusted to the driver's steering specifications and the driver assistance system therefore directs less counter-torque to the driver.
  • a second controller unit which is designed to convert setpoint torque information from the steering angle controller for the servomotor of the electromechanical steering system or information proportional to this setpoint torque information implement steering angle information, yaw rate information or curvature information as second steering control information.
  • the second controller unit is designed to receive setpoint torque information from the steering angle controller for the servomotor of the electromechanical steering system that is weighted with an activation factor, with the activation factor being provided by the first controller unit.
  • Torque information is preferably received from the control circuit of the second control unit and an arithmetic operation is carried out with a setpoint value.
  • the moment information is provided, for example, by the steering angle controller of the electromechanical steering system.
  • the torque information is subtracted from the setpoint and the the resulting control difference is multiplied by the activation factor. The result of this multiplication is then fed to the second controller unit as input information.
  • the magnitude of the torque of the servomotor is mainly a measure of the torque applied to the driver.
  • the fact that the second controller unit now tries to reduce the control difference multiplied by the activation factor effectively reduces the working of the driver assistance function against the driver. The extent of this reduction is determined by the level of the activation factor.
  • the second controller unit is designed to receive the oversteering stiffness information and to adapt the control behavior of the second controller unit based on the oversteering stiffness information.
  • At least one amplification factor of the second controller unit is preferably adjusted as a function of the oversteering stiffness information.
  • a function can be provided that maps the required degree of oversteering stiffness to the at least one amplification factor. There is preferably a reciprocal dependency such that a higher oversteering stiffness is converted to a lower control loop gain and vice versa.
  • the cut-off frequency can be adapted, for example, as a function of the oversteering stiffness information.
  • a function can also be provided here that maps the required degree of oversteering stiffness to the at least one limit frequency.
  • the second controller unit has an absolute value characteristic that falls monotonously above a limit frequency and/or a control behavior in accordance with a PT1 controller.
  • a controller behavior or this type of controller is advantageously suitable for the interactive control of the vehicle through influences of the driver and the driver assistance system.
  • the invention relates to a method for controlling an electromechanical steering system of a vehicle Driving assistance system that provides first steering control information and a control unit with at least one first controller unit, wherein the control unit receives driver moment information that the human driver applies to the steering device, and receives at least one piece of adjustment information dependent on the driving state and/or the driving situation, wherein the control unit receives a second providing steering control information dependent on the driver moment information and the at least one adjustment information and the system modifying the steering system of the vehicle based on the first and second steering control information
  • FIG. 1 shows an example of a schematic representation of a first embodiment of a system for controlling an electromechanical steering system of a vehicle, the electromechanical steering system being controlled by the driver assistance system by means of moment information; and 2 shows an example of a schematic representation of a second embodiment of a system for controlling an electromechanical steering system of a vehicle, wherein the electromechanical steering system is controlled by the driver assistance system by means of desired steering angle information.
  • FIG. 1 shows, by way of example and schematically, a block diagram of a first exemplary embodiment of a system 1 which is used to control a steering system 2 with an electromechanical drive (EPS: electric power steering).
  • EPS electromechanical drive
  • a program-controlled electric servomotor supports the steering movements of the driver or, in the case of autonomous or semi-autonomous driving, carries out at least some of its own steering movements.
  • the steering system 2 has a torque interface, i.e. the steering system 2 is designed to receive, as input information, torque information for the servomotor of the steering system 2 or information proportional to the torque, for example information regarding the current through the servomotor of the steering system 2 to obtain.
  • the system 1 has a driver assistance system 3 that provides a first item of steering control information L1 at an output interface.
  • the driver assistance system can, for example, have an environment recognition unit 3.1, which creates an environment model in the vehicle area by means of a sensor system.
  • the driver assistance system 3 can have a trajectory planner unit 3.2.
  • the trajectory planner unit 3.2 is coupled at least indirectly to the environment recognition unit 3.1 and is designed to receive information from the environment recognition unit 3.1 and to plan travel trajectories based thereon.
  • the driver assistance system 3 preferably has a trajectory following control 3.3. This is coupled at least indirectly to the trajectory planner unit 3.2 and is designed to calculate control information for the vehicle in order to move the vehicle on a calculated and selected travel trajectory.
  • the output information of the trajectory following control 3.3 is preferably a target steering angle cpsoii, which is used to drive along a selected travel trajectory.
  • the driver assistance system 3 preferably also has a steering angle controller 3.4.
  • This steering angle controller 3.4 is coupled at least indirectly to the trajectory following control 3.3 and receives control information from this trajectory following control 3.3, in particular the setpoint steering angle.
  • the steering angle controller 3.4 is preferably designed to provide torque information for the servomotor of the steering system 2 or information proportional to the torque, for example information regarding the current through the servomotor of the steering system 2, as a setpoint specification.
  • the steering angle controller 3.4 can be designed to suppress disruptive effects such as an oscillating steering behavior.
  • the steering angle controller 3.4 preferably provides the first item of steering control information L1.
  • the unit 7 can, for example, be a functional component of the driver assistance system 3 , ie it can be provided in a control unit of the driver assistance system 3 or else in a control unit which is separate from the driver assistance system 3 .
  • the unit 7 can also have means for observing the driver in order to record and process the behavior of the driver, the direction in which he is looking and/or his actions in order to be able to draw conclusions about future driving commands from the driver.
  • the system 1 also has a control unit 4 which is designed to provide a second piece of steering control information L2.
  • the system 1 uses the second item of steering control information L2 to modify the first item of steering control information L1 in such a way that the third, modified item of steering control information L3 created by the modification enables improved cooperative driving, in which the human driver, depending on the driving state and/or the driving situation, even when the driving assistance function is activated, one Lateral control of the vehicle causes greater freedom to participate in the control of the vehicle, so that the impression of externally determined driving behavior is reduced depending on the driving state and/or the driving situation.
  • the control unit 4 has a first interface S1, which is designed to receive driver moment information M.
  • the driver torque information M is torque information or a variable that is proportional to this torque information and indicates what torque the driver applies to the steering device of the vehicle.
  • the driver moment information M is preferably first subjected to an absolute value formation using an absolute value unit 4.1.
  • provided.
  • a counting arrow system was selected in which a positive driver torque is defined in such a way that it has the same effect as a positive motor torque of the electromechanical steering system 2 or as a positive steering angle, which usually indicates cornering to the left.
  • the control unit 4 also has a second interface S2, at which first and second adjustment information A1, A2 are provided.
  • the first and a second piece of adjustment information A1 , A2 are preferably provided by the unit 7 .
  • At least one of the pieces of adjustment information A1, A2 is a variable dependent on the driving state and/or driving situation, ie dependent
  • the first and/or second adjustment information A1, A2 is changed based on the driving condition or the driving situation that the unit 7 recognizes.
  • the first and second pieces of adjustment information A1, A2 are preferably adjusted as a function of the driving state and/or the driving situation.
  • the first adjustment information A1 is preferably a driver torque threshold value, i.e. a threshold value for torque information or a variable proportional to this torque information.
  • the first adjustment information A1 is used in the control unit 4 to define a threshold which, when exceeded, is intended to enable the driver to influence the steering behavior specified by the driver assistance system 3 .
  • and the first adjustment information A1 fed to a subtraction point 4.2, which provides moment difference information DM on the output side.
  • the torque difference information DM is supplied to a first controller unit 5 as input information.
  • the controller unit 5 has the effect of a limiting controller, in such a way that by adapting the control behavior of the first controller unit 5 using the second adaptation information A2, the hardness can be adjusted by means of which the steering behavior specified by the driver assistance system can be overridden by the driver.
  • the first controller unit 5 specifies the torque that the driver has to apply to the steering wheel, above which the driver assistance system becomes increasingly flexible with regard to a different direction desired by the driver.
  • the degree of this compliance is defined by the adjustment information. In other words, the severity of the steering resistance that the driver feels when oversteering the steering input from the driver assistance system is variably adjusted.
  • the second piece of adjustment information A2 is therefore also referred to below as “oversteering stiffness”.
  • the control behavior of the first control unit 5 is changed based on the second adjustment information A2.
  • the controller gain within the first controller unit 5 is influenced by the second adjustment information A2.
  • One or more amplification factors of the first controller unit 5 are influenced in such a way that the desired oversteering stiffness is achieved.
  • the controller gains assume high values. In terms of their amount, these are only limited, for example, by the effort invested in the design and implementation of stabilization measures.
  • the driver perceives the assistance system to be more flexible and less commanding when driving cooperatively.
  • an adjustment of the cut-off frequencies of the first controller unit 5 may be necessary due to the higher loop gain in order to comply with stability criteria.
  • the adjustment of the filter limit frequency(s) of the first controller unit 5 is preferably also based on the second adjustment information A2.
  • the control unit 4, in particular the first regulator unit 5, preferably has a saturation function.
  • the saturation function is like this selected that the maximum value of the output information of the first controller unit 5 or the maximum value of the second steering control information L2 is limited.
  • the amount of the output information of the first controller unit 5 is thus limited by the saturation function in definable thresholds.
  • the definition of these thresholds represents a further degree of freedom for the design of the oversteering behavior.
  • the thresholds can have a defined fixed value or can also be designed depending on the driving situation. Low thresholds allow the counter-torque for the driver to increase again from a certain degree of oversteering. The reason is that with a comparatively low threshold, the amount of first steering control information L1 exceeds the second steering control information L2 from a certain degree of oversteering and the modified steering control information L3 formed by summation point 8 thus increasingly represents the desire of the driver assistance system, which the driver sees as Disturbance of the control circuit corrected.
  • the counter-torque for the driver increases again.
  • One application is that the driver torque is initially relatively low when the desired deviation from the specification of the driver assistance system is small and only increases when the desired deviation is larger, whereby a tolerance zone for the oversteering is haptically transmitted to the driver.
  • High limiting thresholds for the second item of steering control information L2 mean that the first item of steering control information L1 can be overruled.
  • the modified steering control information L3 thus increasingly represents the driver's intention to oversteer, and the control objective of the driver assistance system is pushed further and further back. As a result, the required steering torque for a steering maneuver can be smaller than is necessary without a driver assistance function.
  • An application for this is e.g.
  • the output information provided by the first controller unit 5 is then multiplied by the sign of the driver's moment, as is shown in Fig. 1 is represented by the "sign" block.
  • the “sign” function determines the sign of the driver moment information M
  • the second steering control information item L2 is formed by multiplying the output information of the first controller unit 5 by the sign of the driver moment information M. The result of this is that the control unit 4 provides steering control information L2, independently of the steering direction, which is directed in such a way that the driver's torque is reduced.
  • the second steering control information L2 is transmitted to an addition point 8.
  • FIG. There, the second steering control information L2 and the first steering control information L1 are added and the third steering control information L3 is provided.
  • the addition point 8 can be replaced by a subtraction point, which results in a functionally identical system.
  • the third item of steering control information L3 is fed to a safety barrier SB, which provides fourth item of steering control information L4 on the output side.
  • the safety barrier SB is a unit that monitors and actively limits the manipulated variable before it is physically taken into account in terms of absolute height and gradient.
  • the safety barrier SB is configured, for example, to monitor the modified steering control information L3 with regard to compliance with safety goals and, if necessary, to modify it if the safety goals are not being met.
  • the absolute level of the modified steering control information L3 and its gradient can be monitored and, if necessary, also actively limited.
  • the fourth steering control information L4 forms the input variable of the electromechanical steering system 2.
  • the first controller unit 5 Depending on the driver moment information M, and the first and second adjustment information A1, A2, the first controller unit 5 generates a second steering control information L2, which changes the first steering control information L1 generated by the driver assistance system 3, so that the driver influences steering system 2 of the vehicle, which is dependent on first and second adjustment information A1, A2.
  • information from the functional units 3.1 to 3.4 of the driver assistance system 3 and the electromechanical steering system 2 can be used to record the driving condition or the driving situation.
  • FIG. 2 shows, by way of example and schematically, a block diagram of a second exemplary embodiment of a system 1 that is used to control a steering system 2 with an electromechanical drive.
  • the steering system 2 has an angle interface, i.e. the steering system 2 is designed to receive angle information, in particular setpoint steering angle information cpsoii, as input information.
  • the steering angle controller is preferably integrated into the steering system 2 .
  • the driver assistance system 3 provides the setpoint steering angle information cpsoii as first steering control information L1 at an output interface.
  • the driver assistance system in turn has, for example, an environment detection unit 3.1, which creates an environment model in the vehicle area by means of a sensor system. Furthermore, the driver assistance system 3 can have a trajectory planner unit 3.2.
  • the trajectory planner unit 3.2 is coupled at least indirectly to the environment recognition unit 3.1 and is designed to receive information from the environment recognition unit 3.1 and to plan travel trajectories based thereon.
  • the driver assistance system 3 preferably has a trajectory following control 3.3. This is coupled at least indirectly to the trajectory planner unit 3.2 and is designed to calculate control information for the vehicle in order to move the vehicle on a calculated and selected travel trajectory.
  • output information of trajectory following control 3.3 is first steering control information L1 in the form of setpoint steering angle information cpsoii, according to which a selected travel trajectory is traveled.
  • At least some of the aforementioned units 3.1 to 3.3 of the driver assistance system 3 can, as indicated by the vertical arrows in FIG. 2, be connected to a unit 7, by means of which a driving state detection or driving situation detection is provided.
  • the unit 7 can, for example, be a functional component of the driver assistance system 3, i.e. it can be provided in a control unit of the driver assistance system 3 or else in a control unit that is separate from the driver assistance system 3.
  • the unit 7 can also have means for observing the driver in order to record and process the behavior of the driver, the direction in which he is looking and/or his actions in order to be able to draw conclusions about future driving commands from the driver.
  • the system 1 in turn has a control unit 4 which is designed to provide a second piece of steering control information L2.
  • the system 1 modifies the first steering control information L1 by means of the second steering control information L2 in such a way that by means of the modified steering control information L3 resulting from the modification, improved cooperative driving, in which the human driver, depending on the driving state and/or driving situation, is provided with an activated driving assistance function, which provides lateral control of the Vehicle causes greater freedom in the participation of the control of the vehicle is granted, so that the impression of externally determined driving behavior depending on the driving status and / or driving situation is reduced.
  • the interfaces S1 and S2 of the control unit 4 and the processing of the information received at the interfaces S1 and S2 by the amount unit 4.1 and the first controller unit 5 is identical to the first exemplary embodiment according to FIG 1, so that reference is made to the previous statements. These also apply in the same way to the exemplary embodiment in FIG.
  • a significant difference from the exemplary embodiment according to FIG. 1 is that in the exemplary embodiment according to FIG. 2 the second steering control information L2 is not provided directly by the first controller unit 5, but the first controller unit 5 provides an activation factor AF.
  • the control unit 4 also has a subtraction point 4.2.
  • this subtraction point 4.2 is supplied with a target value, in the exemplary embodiment shown the target value “0” and torque information D1 of the electromechanical steering system 2.
  • the torque information D1 corresponds, for example, to the requested actuating torque of the steering angle controller of the electromechanical steering system 2 or also to a current that is directly proportional to the requested current through the servomotor.
  • the total torque derived from the resulting actual motor current can also be used for this purpose after deduction of the torque or current requirements by the other functions on the control unit of the electromechanical steering system 2 .
  • the torque information D1 is subtracted from the setpoint.
  • the result of this difference is modified based on the activation factor AF.
  • the output information of the subtraction point 4.2 is multiplied by the activation factor AF and the result of the multiplication is supplied to the second controller unit 6 as input information.
  • the activation factor is preferably a rational number in the range between 0 and 1 (AF e [0,1]).
  • the activation factor is influenced by driver moment information M and first and second adjustment information A1, A2.
  • a value of "0" means that the driver perceives hard steering, ie cooperative driving is strongly suppressed.
  • the second controller unit 6 receives the difference weighted with the activation factor AF.
  • the second controller unit 6 is designed, for example, as a torque control loop.
  • the second controller unit 6 is preferably designed as a PT1 controller.
  • the second controller unit 6 is linked to the first controller unit 5 in that the first controller unit 5 generates an activation factor AF with a value between 0 and 1 at its output interface, with which the control difference of the second controller unit 6 is scaled. Without driver interaction, the first controller unit generates an activation factor of 0, as a result of which the torque information of the steering system 2, in particular of the steering angle controller of the steering system 2, is not fed back. When the driver interaction is present, the first controller unit 5 generates an activation factor AF greater than 0 depending on the first and second adjustment information A1, A2.
  • the contribution of the second adjustment information A2 (i.e. the oversteering stiffness) to the activation factor AF is preferably such that a higher second adjustment information A2 , i.e. a higher oversteering stiffness causes a smaller activation factor AF at the output interface of the first controller unit 5.
  • the contribution of the deviation of the driver moment information M from the first adjustment information A1 (i.e. the driver moment threshold) to the activation factor AF is designed in such a way that the activation factor AF becomes greater the further the driver moment information M exceeds the first adjustment information A1, i.e. the activation factor AF becomes all the greater, the greater the driver torque residue.
  • the contributions made by the adjustment information to achieve a desired result can be weighted and, in particular, subjected to a minimum operation.
  • weighting factors k1, k2 are used, which offer degrees of freedom in the design of the first controller unit.
  • the second piece of adjustment information A2 preferably assumes values in the range between 0 and 1.
  • DM min(1,max(0,(
  • the second adjustment information A2 can also be used to influence the control behavior of the second control unit 6.
  • the second adjustment information A2 can be used to increase the controller gain of the second controller unit 6 when the second adjustment information A2 decreases.
  • it can be advantageous to also adjust the parameters of the second controller unit 6 that determine the frequency response at the same time, for example in the form of a shift in pole and/or zero points.
  • the driver interaction can also be adjusted as a function of the current driving situation using only the first adjustment information A1 , only the second adjustment information A2 or a combination of both adjustment information A1 , A2 . If only one of the two items of adjustment information A1, A2 is changed dynamically as a function of the driving condition or the driving situation, the respective other item of adjustment information is opened set a fixed value. This value is preferably selected in such a way that, viewed on its own, it leads to an activation factor AF of 1, ie allows maximum dynamic driver intervention.
  • Steering control information L2 is transferred to an addition point 9. There, the second item of steering control information L2 and the first item of steering control information L1 are added, thereby providing modified item of steering control information L3.
  • the third item of steering control information L3 is preferably in turn fed to a safety barrier SB, which provides fourth item of steering control information L4 on the output side.
  • the safety barrier SB is a unit that monitors and actively limits the manipulated variable before it is physically taken into account in terms of absolute height and gradient.
  • the safety barrier SB is configured, for example, to monitor the modified steering control information L3 with regard to compliance with safety goals and, if necessary, to modify it if the safety goals are not being met.
  • the absolute level of the modified steering control information L3 and its gradient can be monitored and, if necessary, also actively limited.
  • the fourth steering control information L4 forms the input variable of the electromechanical steering system 2.
  • the second controller unit 6 Depending on the driver moment information M and the first and second adjustment information A1, A2, the second controller unit 6 generates a second steering control information L2, which changes the first steering control information L1 generated by the driver assistance system 3, so that a dynamic influence of the driver on the steering system 2 of the vehicle that is dependent on the first and second adjustment information A1, A2 is possible.
  • the operation of the control unit 4 is such that the control unit 4, for example, a target value of torque information Dl an angle controller of the electromechanical steering system 2 and depending on the magnitude of the torque difference DM and the second adjustment information A2, this torque difference DM is reduced with the aid of the second controller unit 6.
  • the second controller unit 6 generates a second item of steering control information L2 (steering angle bias signal), which is added to the first item of steering control information L1 provided by the trajectory following control 3.3.
  • a control loop is formed which increasingly reduces the torque difference DM.
  • information from the electromechanical steering system 2 can also be used to record the driving condition or the driving situation.
  • the unit 7 is designed to recognize and evaluate the driving situation or the driving state.
  • the unit 7 can also observe the driver, for example using a camera, and derive the driver's behavior from this.
  • the unit can provide information as to whether the driver is being steered in the same direction as the specification of the driver assistance system or whether the driver is steering against the specification of the driver assistance system.
  • the unit 7 can, for example, react to driving situations or driving states or to the driver's behavior as follows:
  • the counter-torque of the driver assistance system 3 should be clearly noticeable and act in the direction of the safe lane area.
  • the amount of the first adjustment information A1 (driver torque threshold value) and the second adjustment information A2 (oversteering stiffness) assume high values;
  • the first adjustment information A1 (driver moment threshold) and the second Adaptation information A2 (oversteering stiffness) assumes low values in terms of absolute value.
  • the driver signals to the driver assistance system 3, for example via the Flandmoment, that there is a desire for cooperation, this should be possible with little steering torque effort, i.e. with low intensity. Examples of this would be the selection of an alternative driving route past an obstacle on the right instead of on the left, or the driver's desire for a constant lateral offset instead of an exact lane center guidance, which he communicates to the driver assistance system 3 via appropriate steering.
  • the first adjustment information A1 (driver torque threshold value) and the second adjustment information A2 (oversteering stiffness) assume low values in terms of absolute value.
  • the driver assistance system 3 reaches the limits of the electromechanical steering system when cornering and the driver would like to support the lateral lateral guidance in order to prevent the vehicle from leaving the curve, this should not appear to the driver as countersteering with the result of a high counter-torque expressed on the steering wheel, but as a support steering.
  • the driver only has to apply a portion of the steering force that remains after deducting the maximum steering force of the electromechanical steering system that is due to the limitation.
  • the first adjustment information A1 (driver torque threshold value) and the second adjustment information A2 (oversteering stiffness) assume high values in terms of amount, so that the control unit 4 leaves the first steering control information L1 unchanged and this remains unchanged or almost unchanged (i.e. the second steering control information is zero or very small) via the safety barrier SB to the electromechanical steering system 2.”
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • the driver can also receive active steering assistance by using the controller unit 5 does not limit or only limits at high values of the output signal.
  • an evasive emergency steering maneuver e.g. characterized by a high steering angle speed
  • the driver can also receive active steering assistance by using the controller unit 5 does not limit or only limits at high values of the output signal.
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • the amount of first adjustment information A1 (driver torque threshold) and second adjustment information A2 (oversteering stiffness) is set to high values if the driver steers more dynamically than the specification of a determined limit evasion trajectory.
  • This limit avoidance trajectory is defined by the fact that the vehicle This trajectory will be far away from the obstacle, but at the same time there is a high probability that it will lose traction and become unstable.
  • the amount of first adjustment information A1 (driver torque threshold) and second adjustment information A2 (oversteering stiffness) is set to low values if the driver selects a trajectory through his steering maneuver that is between the optimum and the limit -Avoidance trajectory lies.
  • the optimal avoidance trajectory and the limit avoidance trajectory are continuously re-determined and the driver's action is re-evaluated in each case.
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • first adjustment information A1 driver torque threshold value
  • second adjustment information A2 oversteering stiffness
  • the first adjustment information A1 (driver torque threshold value) is preferably designed as a function of internal control error variables of the lateral control, for example as follows:
  • the first adjustment information A1 is higher, the greater the difference between the actual steering wheel angle and the target steering wheel angle;
  • the first adjustment information A1 is higher, the greater the difference between the actual yaw rate and the target yaw rate.
  • the second adjustment information A2 (oversteering stiffness) is preferably also designed as a function of internal control error variables of the lateral control, specifically as follows, for example:
  • the second adjustment information A2 is higher, the greater the lateral distance of the vehicle from the target trajectory; - The second adjustment information A2 is higher, the greater the difference between the actual steering wheel angle and the target steering wheel angle;
  • the second adjustment information A2 is higher, the greater the difference between the actual yaw rate and the target yaw rate.
  • the first and second adjustment information A1, A2 is preferably selected to be smaller if the driver steers against the specification of the driver assistance system and selects an alternative route that does not result in less driving safety.
  • the first and second adjustment information A1, A2 are preferably selected to be larger if the driver has the same vehicle guidance goal as the driver assistance system or if the driver's alternative route leads or will lead to less driving safety.
  • the driving safety can be evaluated by an expert system on the basis of the predicted collision probability and the predicted loss of adhesion potential at the wheels.
  • control unit 4 can be present, for example, on a control unit of the driver assistance system 3 .
  • control unit 4 can also be implemented on the control device of the electromechanical steering system 2 .
  • the interface between the control unit of the driver assistance system 3 and the control unit of the electromechanical steering system 2 is expanded for the transmission of the first and second adjustment information A1, A2.
  • the system 1 can advantageously also have one or more of the following functionalities:
  • the values may need to be smoothed/interpolated before the conversion by the control unit 4 in order to avoid an unwanted jerk in the steering wheel.
  • they Preferably they have first and second adjustment information A1, A2 have a continuous character and are determined, for example, by fuzzy logic operations.
  • the driver moment can also be influenced, for example, by the control unit 4 replanning the target trajectory as a function of the steering activity of the driver, instead of the limitation regulation described above.
  • the planning of a trajectory which leads e.g. exactly along the lane chosen by the driver, results in a counter-torque of 0 Nm for the driver, neglecting the initial states of the controller. Planning a trajectory to the right or left of the trajectory currently being driven leads to a steering recommendation to the right or left.
  • a new trajectory due to driver steering which leads to less driver steering torque, also implicitly becomes part of a control loop, so that additional precautions on the part of trajectory planning are necessary to ensure stability, especially with regard to the generally larger latency between a triggered one rescheduling and the impact on driver momentum.
  • the trajectory would have to be replanned in each scanning step (e.g. every 10 ms). of the currently impressed vehicle movement by the driver. This is associated with a high computational effort and yet cannot eliminate angle controller components with a damping character.
  • the first or second adjustment information A1, A2 with the value “0” is selected, an inhibiting contribution of zero can be achieved at the torque interface to the electromechanical steering system 2 by the angle control.
  • the inhibition by the angle controller can be greatly reduced in practice with adaptation factors A1, A2 from zero down to low residual torques.
  • a coordinated overall behavior can only be achieved from the interaction of driver torque limitation and a new trajectory planning.
  • the second adjustment information A2 (oversteering stiffness) can also be implicitly influenced in that the first adjustment information A1 (driver torque threshold value) is controlled as a function of the steering wheel deflection.
  • the effort to ensure stability is also higher here.
  • the method described can also be used if, instead of a steering angle specification for the steering system 2, a yaw rate or curvature specification takes place. Instead of a steering angle bias, the control unit 4 then generates correction variables for the target yaw rate or target curvature.
  • the actual steering wheel angle can also be used within the first control unit 4 in order to limit the driver torque more dynamically when oversteering.
  • the target steering angle is mixed proportionally with the actual steering angle at a driver torque above the first adjustment information A1, until the target steering angle ultimately corresponds to the actual steering angle as the driver torque information M continues to rise.
  • the control difference of the steering angle controller of the electromechanical steering system 2 becomes zero and the torque requirement for the servomotor of the steering system 2 cannot initially continue to rise.
  • a negative feedback of the torque request using the second controller unit is still required.
  • the setpoint torque information of the steering angle controller minus a defined proportion can be taken into account within the control unit 4 instead of feeding back the entire setpoint torque information of the steering angle controller in the fixed value control.
  • This proportion is then to be defined on the basis of the first and second adjustment information A1, A2. If the second adjustment information (oversteering stiffness) is high or if the driver torque information M is still low, this proportion is selected to be high. If the driver moment information M increases or if less second adjustment information A2 (oversteering stiffness) is required, this proportion is selected to be small with the end value of 0. This procedure can be
  • Steering angle controller implementations on the steering system 2 with high dynamics may be required, since otherwise the steering angle setpoint torque working against the driver is completely reduced too early and the second adjustment information A2 (oversteering stiffness) is perceived as too low.
  • the subtraction of a portion of the steering angle setpoint torque can also be converted into a corresponding setpoint value of the second controller unit.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Control Of Driving Devices And Active Controlling Of Vehicle (AREA)

Abstract

L'invention se rapporte à un système permettant d'actionner un système de direction électromécanique (2) d'un véhicule, comprenant un système d'aide à la conduite (3), qui est conçu pour générer un premier élément d'informations de commande de direction (L1), et une unité de commande (4) ayant au moins une première unité de dispositif de commande (5), l'unité de commande (4) présentant une première interface (S1), qui est conçue pour recevoir des informations de couple d'entraînement (M), et au moins une seconde interface (S2), qui est conçue pour recevoir au moins un élément d'information de réglage (A1, A2) qui dépend de l'état de conduite et/ou de la situation de conduite, l'unité de commande (4) étant conçue pour fournir un second élément d'information de commande de direction (L2) qui dépend des informations de couple d'entraînement (M) et du ou des éléments d'information de réglage (A1, A2), et le système (1) étant conçu pour fournir un élément modifié d'information de commande de direction (L3) au système de direction (2) du véhicule sur la base des premier et second éléments d'information de commande de direction (L1, L2), un mouvement de direction étant exécuté sur le système de direction électromécanique (2) sur la base dudit élément modifié d'information de commande de direction.
EP22716328.4A 2021-03-22 2022-03-09 Système et procédé permettant d'actionner un système de direction électromécanique d'un véhicule Pending EP4313729A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102021202740.7A DE102021202740A1 (de) 2021-03-22 2021-03-22 System und Verfahren zur Ansteuerung eines elektromechanischen Lenksystems eines Fahrzeugs
PCT/DE2022/200037 WO2022199761A1 (fr) 2021-03-22 2022-03-09 Système et procédé permettant d'actionner un système de direction électromécanique d'un véhicule

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EP4313729A1 true EP4313729A1 (fr) 2024-02-07

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US (1) US20240174292A1 (fr)
EP (1) EP4313729A1 (fr)
JP (1) JP2024508501A (fr)
CN (1) CN117083217A (fr)
DE (1) DE102021202740A1 (fr)
WO (1) WO2022199761A1 (fr)

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DE102019133025A1 (de) * 2019-12-04 2021-06-10 Zf Automotive Germany Gmbh Verfahren zur Positionsregelung für ein Lenksystem
US11975777B2 (en) 2021-04-02 2024-05-07 Steering Solutions Ip Holding Corporation Systems and methods for over learning protection for torque steer mitigation

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DE102007011275B4 (de) 2007-03-08 2012-03-15 Volkswagen Ag Verfahren und Vorrichtung zur Umsetzung einer Lenkmomentenempfehlung für ein Spurhalteassistenzsystem mit einer elektromechanischen Lenkung
DE102014208786B4 (de) * 2014-05-09 2017-08-10 Bayerische Motoren Werke Aktiengesellschaft Querführungsregelungsstruktur zur Erzeugung einer Lenkvorgabe für eine Hilfskraftlenkung eines Kraftfahrzeugs mit einem Bahnführungsregler und einem über eine Krümmungsvorgabe angesteuerten, nachgelagerten Fahrzeugführungsregler
DE102016215724A1 (de) 2016-08-22 2018-02-22 Volkswagen Aktiengesellschaft Verfahren und Vorrichtung zum Betreiben eines Lenksystems mit elektromechanischer Lenkunterstützung
DE102016218845B4 (de) * 2016-09-29 2023-04-27 Volkswagen Aktiengesellschaft Verfahren und Vorrichtung zum Betreiben eines Lenksystems mit elektromechanischer Lenkunterstützung
US11358630B2 (en) * 2019-07-10 2022-06-14 Hyundai Mobis Co., Ltd. Electric steering apparatus for vehicle and method for controlling the same

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CN117083217A (zh) 2023-11-17
WO2022199761A1 (fr) 2022-09-29
JP2024508501A (ja) 2024-02-27
US20240174292A1 (en) 2024-05-30
DE102021202740A1 (de) 2022-09-22

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