Wheel suspension for controlling the longitudinal and / or lateral dynamics of a motor vehicle

Abstract

Wheel suspension (100) for controlling the longitudinal and / or lateral dynamics of a motor vehicle (200) comprising: - a steering actuator connection (102), - a cycle connection (104), - a steering device (106), wherein the steering actuator connection (102) is configured to rotate the wheel connection (104) about a steering axis (X), wherein the wheel connection (104) is designed to transmit a drive torque and / or a braking torque to a wheel (108), wherein the steering device is configured to control the drive torque and / or the braking torque of the wheel connection (104) in such a way that a rotation (110) of the wheel connection (104) about the steering axis (X) is controllable, wherein the steering device (106) further comprises: - a steering clutch, wherein the steering clutch is configured to at least partially restrict the rotation (110) of the wheel connection (104) about the steering axis (X), characterized in that wherein the wheel suspension (100) has at least one condition sensor (114), wherein the condition sensor (114) is configured to detect a failure of the steering actuator connection (102), the condition sensor (114) is designed to detect a distortion torque of the wheel connection (104) about the steering axis (X), wherein the rotation (110) of the wheel connection (104) about the steering axis (X) is adjustable as a function of the distortion torque by the steering clutch, and wherein the condition sensor (114) is configured to detect a steering torque deviation of the steering actuator connection (102), wherein the steering clutch is designed to at least partially compensate for the steering torque deviation of the steering actuator connection (102).

Description

Field of the invention

[0001] The invention relates to a wheel suspension for controlling the longitudinal and / or transverse dynamics of a motor vehicle, a motor vehicle and a method for controlling the longitudinal and / or transverse dynamics of a motor vehicle. Background of the invention

[0002] In conventional steering systems, where the steering wheel is mechanically connected to the handlebar, a failure of a steering actuator is generally not critical, as the driver can intervene using the steering wheel as a fallback. In steer-by-wire systems, this is no longer possible, as there is no longer any mechanical connection to the wheel. For this reason, redundancies are required to ensure functional safety in the event of a malfunction or failure of a steering actuator. State-of-the-art systems are complex and expensive to implement due to the precautions required in the event of a fault. In many cases, a mechanical or hydraulic fallback system is provided in addition to at least duplicate actuators. This fallback system, in turn, increases the complexity, weight, space requirements, and costs of the steering system.

[0003] From DE 10 2016 007 445 A1, a wheel suspension for controlling the longitudinal and / or transverse dynamics of a motor vehicle is known. This comprises a steering actuator connection, a wheel connection, and a steering device. The steering actuator connection is configured to rotate the wheel connection about a steering axis, wherein the wheel connection is configured to transmit a drive torque and / or a braking torque to a wheel, wherein the steering device is configured to control the drive torque and / or the braking torque of the wheel connection such that rotation of the wheel connection about the steering axis is controllable. Summary

[0004] With the embodiments described below, an improved wheel suspension can be provided in an advantageous manner.

[0005] One aspect relates to a wheel suspension for controlling the longitudinal and / or lateral dynamics of a motor vehicle, comprising a steering actuator connection, a wheel connection, and a steering device. The steering actuator connection is configured to rotate the wheel connection about a steering axis. Furthermore, the wheel connection is configured to transmit a drive torque and / or a braking torque to a wheel. Furthermore, the steering device is configured to control the drive torque and / or the braking torque of the wheel connection such that rotation of the wheel connection about the steering axis is controllable.

[0006] The advantage of this embodiment can be that, particularly in a steer-by-wire steering system using a steering clutch in conjunction with the wheel connection, rotation around the steering axis can be enabled to stabilize a vehicle, especially in the event of a steering actuator failure. Furthermore, the assembly process of the wheel suspension is significantly simplified, since multiple steering actuators do not need to be installed; instead, all components can be arranged within one wheel suspension.

[0007] In other words, the steering device can be designed to align the wheel connection with targeted interventions in the form of drive and / or braking torques so that the wheel connection is steered in a desired direction of travel. In particular in the event of a steering actuator failure, the control system can adjust the orientation of the wheel connection, in particular along a steering angle of the wheel connection, using the drive and / or braking torque. This can be advantageous because the lateral dynamics of the vehicle can be changed despite a failure of the steer-by-wire steering. For example, in the case of a left front wheel of a four-wheeled vehicle, an increased drive torque can steer the wheel connection into a right-hand bend. Alternatively, a left-hand bend can be set on the left front wheel using a braking torque.

[0008] According to one embodiment, the steering device may further comprise a steering clutch. The steering clutch is configured to at least partially restrict rotation of the wheel connection about the steering axis.

[0009] This embodiment can have the advantage that the wheel connection can also contribute to the propulsion of the motor vehicle, since in a drive the steering clutch prevents rotation of the wheel connection around the steering axis and thus a drive torque can be generated.

[0010] In other words, the steering clutch enables the wheel suspension to control both the longitudinal and lateral dynamics of a motor vehicle, particularly when the steering actuator connection has failed. If the drive or braking torque on the wheel to be steered is selected such that it generates a torque about the steering axis that can overcome the existing resistance and restoring torques and, if applicable, drag torques of the defective steering actuator about the steering axis, this causes this wheel to steer about a steering axis. If the wheel is to additionally contribute a drive and / or braking torque of any magnitude to the longitudinal guidance of the vehicle during the steering maneuver or after the steering maneuver has been completed (constant steering angle), a steering clutch is required to prevent any unintentional steering movement of the wheel.The steering clutch can enable targeted intervention in the degree of freedom of movement of the wheel and the steering axle. This can, for example, be a mechanism that blocks (locks) movement around the steering axis in a certain position or that, through targeted control of a desired compensation torque, also generates torques acting on the steering axle. The steering clutch can be designed as a friction brake, a magnetic counterforce brake, or any other suitable brake. In addition, the wheel suspension can have a steering actuator connection to which, in particular, a steering actuator can be attached. The steering actuator connection can, in particular, connect the steering clutch to the steering actuator. In addition, the wheel suspension can have a wheel connection that can be driven, in particular, by a wheel hub motor and / or by a shaft.In addition, the wheel connection can have a brake unit designed to transmit a braking torque to a wheel. The brake unit can be designed using a regenerative brake, wherein a wheel hub motor can be attached to the wheel connection, which can assume both the functions of drive torque and braking torque. In addition, the wheel connection is arranged such that it can rotate about a steering axis. In addition, the steering clutch is arranged on the wheel connection and the steering actuator connection in such a way that the steering clutch can at least partially restrict rotation about the steering axis of the wheel connection. At least partially restricting can mean influencing the rotation and / or the angular velocity of the wheel connection about the steering axis by means of the steering clutch.

[0011] According to one embodiment, the steering clutch can be configured to selectively lock or release the rotation of the wheel connection about the steering axis. This can be advantageous because the steering clutch can influence both the longitudinal and lateral dynamics of a motor vehicle. Thus, particularly in front-wheel drive motor vehicles, both the longitudinal and lateral dynamics can be adjusted even in the event of a steering actuator failure. In other words, the steering clutch can have a mechanism designed to lock or release the rotation of the wheel connection about the steering axis. The selective locking or releasing can, in particular, involve locking, blocking, or the like, which can be achieved in particular by an actuator that can comprise the steering clutch.

[0012] According to one embodiment, the steering clutch can be configured to generate a locking torque so that the wheel connection can rotate about the steering axis at a desired angular velocity and / or a desired steering angle. This can have the particular advantage that a combination of longitudinal and lateral dynamic changes of the motor vehicle can be adjusted at the wheel suspension, since the braking torque enables the steering clutch to both change the steering direction and drive the wheel of the wheel connections using a drive torque. In other words, the steering clutch comprises an actuator configured to generate a locking torque or a braking torque so that the wheel connection can rotate about the steering axis at a predefined steering angle and / or steering angular velocity.The braking torque can be generated using a mechanism, in particular a friction brake or a magnetic counterforce. The desired angular velocity can, in particular, be a change in the steering angle relative to the motor vehicle over time. The desired steering angle can be selected, in particular, relative to the motor vehicle on which the wheel suspension is mounted.

[0013] According to one embodiment, the wheel connection can have a decoupling unit that can be arranged between the steering actuator connection and the steering axle. Furthermore, the decoupling unit can be designed to decouple the steering actuator connection from the wheel connection in the event of a failure of the steering actuator connection. This can have the particular advantage that, in the event of a failure of the steering actuator connection or the steering actuator, a drag torque or the like at the wheel connection is prevented, since the decoupling unit decouples the steering actuator connection from the wheel connection. The decoupling unit can, in particular, be an activatable or deactivatable freewheel, which can, in particular, interrupt a torque transmission between the steering actuator and the wheel connection.In particular, the failure of the steering actuator connection can also be due to a disturbance in the torque of the steering actuator, for example the steering actuator only generates too little or too much torque.

[0014] According to the invention, the wheel suspension has at least one condition sensor, wherein the condition sensor can be configured to detect a failure of the steering actuator connection. This can have the particular advantage that the condition sensor can independently detect a disturbance in the longitudinal and / or lateral dynamics of the wheel suspension, thus enabling a safe and rapid switchover to the control of the longitudinal and / or lateral dynamics using the steering clutch and the wheel connection. The condition sensor can in particular be a torque sensor, an electronic monitoring unit, or any other type of sensor suitable for monitoring the condition of a steering actuator and / or a torque transmission. The failure of the steering actuator connection can in particular describe a defect in the steering actuator, as well as excessively high or too low torque delivered by the steering actuator.The condition sensor may be capable of comparing an actual torque to a desired torque so that the condition sensor can detect whether the steering actuator is transmitting too high or too low a torque to the wheel connection.

[0015] According to the invention, the condition sensor is connected to a central logic unit of the motor vehicle, in particular an ECU or ECM, wherein the logic unit of the motor vehicle can be configured to control the steering brake such that the wheel connection can be aligned with a direction of travel of the motor vehicle, in particular via the steering clutch. In other words, the central logic unit of the motor vehicle, particularly in combination with an electronic stability program (ESP), is capable of bringing the motor vehicle into a stable driving situation with the aid of the steering clutch and the wheel connection and of enabling a change in the longitudinal and lateral dynamics of the motor vehicle even in the event of a steering actuator failure.

[0016] According to the invention, the condition sensor is designed to detect a distortion moment of the wheel connection about the steering axis, wherein the rotation of the wheel connection about the steering axis is adjustable by the steering clutch as a function of the distortion moment. In other words, the condition sensor can detect a distortion moment at the wheel connection, for example a stiffness of the wheel connection about the steering axis or another fault in the bearing of the wheel connection. This distortion moment can be incorporated into the control of the steering clutch so that the control of the steering clutch can be improved such that other external factors, such as a distortion moment at the wheel connection, can be incorporated into the determination of the longitudinal and / or lateral dynamics. Adjustable means in particular that an actuator, which can be designed to control the steering clutch, can adjust the braking torque of the steering clutch as a function of the distortion moment.

[0017] According to one embodiment, the condition sensor can be configured to detect a steering torque deviation of the steering actuator connection. The steering clutch can be configured to at least partially compensate for the steering torque deviation of the steering actuator connection. This can have the particular advantage that the steering clutch can be used even in the event of a partial failure of the steering actuator, thus ensuring stability in the longitudinal and / or lateral dynamics of the motor vehicle. The steering actuator can, in particular, apply a torque to the steering actuator connection, wherein the condition sensor is capable of evaluating the torque of the steering actuator on the steering actuator connection based on a target and an actual state. A steering torque deviation describes the deviation between the actual and target state.The steering torque deviation can have a threshold value that acts as a buffer until the steering clutch intervenes in the longitudinal and lateral dynamics of the vehicle. In particular, the steering clutch can partially compensate for the steering torque deviation of the steering actuator connection, so that the negative effect on the longitudinal and lateral dynamics of the vehicle can be minimized.

[0018] According to one embodiment, the wheel suspension can further comprise a wheel, wherein a steering roll radius and / or a disturbance force lever arm of the wheel cannot have a zero pass. This can have the particular advantage that the steering axis of the wheel is selected such that the longitudinal and lateral dynamics can be controlled by the steering clutch in any wheel position. The steering roll radius can describe the horizontal distance between the wheel center plane and the point where the spread axis penetrates the roadway at the steering axle of the motor vehicle. The disturbance force lever arm can describe the smallest distance between the spread axis and the wheel center point. In particular, neither the steering roll radius nor the disturbance force lever arm have a zero pass or are equal to 0.

[0019] A further aspect of the invention relates to a motor vehicle having at least one logic unit configured to control the motor vehicle in longitudinal and / or transverse dynamics. Furthermore, the motor vehicle may have an acceleration unit configured to drive and brake the motor vehicle. Furthermore, the motor vehicle may have a steering unit configured to change a direction of travel of the motor vehicle. Furthermore, the motor vehicle may have at least one wheel suspension, as described above and below, wherein the wheel suspension includes a steering device, in particular a steering clutch. Furthermore, the logic unit may be configured, particularly in the event of an at least partial failure of the steering unit, to control the steering device, in particular the steering clutch, in conjunction with the acceleration unit in such a way that a direction of travel of the motor vehicle is changed.

[0020] This can offer the particular advantage that the vehicle remains stable, and in particular remains steerable, even if the steering actuator of the steering unit fails. The logic of the motor vehicle can be an ECU or ECM. The acceleration unit can be, in particular, a wheel hub motor with a braking unit so that it can drive and brake at least one wheel. The steering unit can, in particular, be a steer-by-wire concept, with a steering input provided inside the vehicle and the steering unit being attachable to the vehicle frame.

[0021] A further aspect of the invention relates to a method for controlling longitudinal and lateral dynamics of a motor vehicle, which comprises at least the steps: - Determining the functionality of a steering actuator connection, - Receiving a longitudinal and / or lateral dynamic signal, - Controlling a steering actuator connection and / or a steering device, in particular a steering clutch, depending on the functionality of the steering actuator connection and the received longitudinal and / or lateral dynamics signal.

[0022] The method can, in particular, offer the advantage that, with the aid of a simple control system, the longitudinal and / or lateral dynamics of a motor vehicle can be maintained, particularly in the event of a steering actuator failure. In other words, the method determines the functionality of the steering actuator, in particular whether or not a rotary steering torque is acting on the steering actuator connection. Subsequently, a longitudinal and / or lateral dynamics signal can be received based on steering inputs or a control signal from an ESP system or similar. Depending on the functionality of the steering actuator connection and the received longitudinal and / or lateral dynamics signal, the steering clutch can be controlled such that the longitudinal and / or lateral dynamics of the vehicle can be maintained, particularly if the steering actuator fails.

[0023] Features and elements of the wheel suspension, as described above and below, may be features, elements and steps of the method, as described above and below, and vice versa.

[0024] A further aspect of the invention relates to a program element which, when executed on a logic of a motor vehicle, instructs the motor vehicle to carry out steps of the method as described above and below.

[0025] A further aspect of the invention relates to a computer-readable medium on which a program element as described above and below is stored.

[0026] In the following, embodiments of the invention are described with reference to the figures. Short description of the characters Fig. 1 shows a wheel suspension according to an embodiment of the invention. Fig. 2 shows a motor vehicle according to an embodiment of the invention. Fig. 3 shows a flowchart illustrating steps of a method for controlling longitudinal and / or lateral dynamics of a motor vehicle according to an embodiment of the invention. Fig. 4 shows a schematic structure of a wheel suspension according to an embodiment of the invention.

[0027] The figures are merely schematic and not to scale. In the figures, identical, equivalent, or similar elements may be provided with the same reference numerals. Detailed description of implementation examples

[0028] Fig. 1 shows a wheel suspension 100 having at least one steering actuator connection 102. The steering actuator connection 102 can be arranged, in particular, between the steering axis X and the steering actuator 103. A decoupling unit 112 can be arranged between the steering actuator connection 102 and the steering actuator 103. In addition, the wheel suspension 100 can have a wheel connection 104 that can rotate about the steering axis X. A wheel 108 can be attached to the wheel connection 104. The wheel 108 can have a wheel center 116. In addition, the disturbance force lever arm 150 can be arranged between the steering axis X and the wheel center 116. Since the wheel center 116 is not the same as the steering axis X, the disturbance force lever arm 150 is not zero. In addition, the wheel suspension 100 can have the steering device 106. In addition, the steering device 106 can include the steering coupling. The steering coupling can, in particular, limit a rotation 110 of the wheel connection 104 about the steering axis X.A logic unit 120 of the motor vehicle 200 can be arranged in signal communication with the steering clutch. Furthermore, the steering axis X can be defined on or by a cross member 118. The wheel connection 104 can also be secured to the cross member 118. Furthermore, the wheel suspension 100 can have a status sensor 114, which can be configured, in particular, to monitor the functionality of the steering actuator 103 and the steering actuator connection 102.

[0029] Fig. 2 shows a motor vehicle 200 having at least one acceleration unit 202 configured to accelerate and brake the vehicle 200, in particular along the longitudinal axis Y. Furthermore, the motor vehicle 200 may have a steering unit 204 configured to change a direction of travel of the motor vehicle 200, in particular along the transverse axis Z. The longitudinal axis Y and the transverse axis Z may form a plane.

[0030] The steering axis X can be arranged orthogonally to this plane. Furthermore, the motor vehicle can have a steering input 206, which enables a driver of the motor vehicle 200 to change the direction of travel. The steering input 206 can have a signal connection 208 with the steering unit 204. Furthermore, the motor vehicle 200 can have a wheel suspension 100. The steering unit 204 and / or the wheel suspension 100 can have the logic 120 of the motor vehicle and / or be in signal connection with the logic 120.

[0031] Fig. 3 shows a flowchart illustrating steps of a method for controlling the longitudinal and / or lateral dynamics of a motor vehicle according to an exemplary embodiment of the invention. In a step S1, the functionality of a steering actuator connection is determined. Furthermore, the method may include the step S2 of receiving a longitudinal and / or lateral dynamics signal. Furthermore, the method may include the step S3 of controlling a steering actuator and / or a steering clutch depending on the functionality of the steering actuator connection and the received longitudinal and / or lateral dynamics signal. All steps of the method can occur simultaneously or trigger one another.

[0032] Fig.4 shows a wheel suspension 100 according to one exemplary embodiment. The cross member 118 can be fixed to the motor vehicle 200. The cross member 118 forms the steering axis X, on which the wheel connection 104 can be arranged. The wheel 108 can be fixed to the wheel connection 104. The wheel 108 rests on the base surface 140. The steering roll radius 130 is negative and thus not zero, since the steering axis X does not intersect the axis of the wheel 108 and / or the wheel center 116 at the level of the support surface of the wheel 108 or the base surface 140. The steering roll radius 130 would be positive if the steering axis X intersected the axis of the wheel 108 and / or the axis of the wheel center 116 below the base surface 140. This can in particular have the advantage that the wheel 108 can be rotated about the steering axis X by means of the steering coupling. List of reference symbols 100 Wheel suspension 102 Steering actuator connection 103 Steering actuator 104 Bicycle connection 106 Steering device 108 wheels 110 rotations 112 Decoupling unit 114 Condition sensor 116 Wheel center 118 cross members 120 Logic 130 steering radius 140 floor space 150 disturbance force lever arm 200 motor vehicles 202 acceleration unit 204 Steering unit 206 Steering input 208 Signal connection S1 Determine S2 Receive S3 control

Claims

[1] Wheel suspension (100) for controlling the longitudinal and / or transverse dynamics of a motor vehicle (200), comprising: - a steering actuator connection (102), - a bicycle connection (104), - a steering device (106), wherein the steering actuator connection (102) is adapted to rotate the wheel connection (104) about a steering axis (X), wherein the wheel connection (104) is designed to transmit a drive torque and / or a braking torque to a wheel (108), wherein the steering device is configured to control the drive torque and / or the braking torque of the wheel connection (104) such that a rotation (110) of the wheel connection (104) about the steering axis (X) is controllable.wherein the steering device (106) further comprises: - a steering clutch, wherein the steering coupling is designed to at least partially restrict the rotation (110) of the wheel connection (104) about the steering axis (X), characterized bythat the wheel suspension (100) has at least one condition sensor (114), wherein the condition sensor (114) is configured to detect a failure of the steering actuator connection (102), the condition sensor (114) is designed to detect a distortion moment of the wheel connection (104) about the steering axis (X), wherein the rotation (110) of the wheel connection (104) about the steering axis (X) is adjustable as a function of the distortion moment by the steering coupling, and wherein the condition sensor (114) is configured to detect a steering torque deviation of the steering actuator connection (102), wherein the steering clutch is configured to at least partially compensate for the steering torque deviation of the steering actuator connection (102). [2] Wheel suspension according to claim 1, wherein the steering coupling is arranged to selectively lock or release the rotation (110) of the wheel connection (104) about the steering axis (X). [3] Wheel suspension according to one of claims 1-2, wherein the steering coupling is arranged to form a locking torque so that the rotation (110) of the wheel connection (104) about the steering axis (X) takes place at a desired angular velocity and / or a desired steering angle. [4] Wheel suspension according to one of the preceding claims, further comprising a wheel (108), wherein a steering roll radius (130) and / or a disturbance force lever arm (150) of the wheel (108) does not have a zero-crossing. [5] Wheel suspension according to one of the preceding claims, wherein the wheel connection (104) has a decoupling unit (112) which is arranged between the steering actuator connection and the steering axle and which is designed to decouple the steering actuator connection (102) from the wheel connection (104) in the event of a failure of the steering actuator connection (102). [6] Motor vehicle (200), comprising: - a logic (120) which is designed to control the motor vehicle in a longitudinal and / or transverse dynamic, - an acceleration unit (202) which is designed to drive and brake the motor vehicle (200), - a steering unit (204) which is designed to change a direction of travel of the motor vehicle (200), - at least one wheel suspension (100) according to one of claims 1 to 5, wherein the logic is configured to control the steering device (106) in conjunction with the acceleration unit (202) in the event of an at least partial failure of the steering unit (204) such that a direction of travel of the motor vehicle is changed.

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