Operating arrangement for a steer-by-wire steering system of a motor vehicle

Abstract

A control arrangement for a steer-by-wire steering system of a motor vehicle is described, comprising a mechanical control element (1) located in the passenger compartment of the motor vehicle. The control element (1) is rotatably mounted about a predetermined axis of rotation (x) for inputting a steering request from the driver of the motor vehicle and has a support surface for the driver's hand. The control element (1) has a front part (2) that is rotatably mounted about an axis of rotation (y) and serves to accelerate or brake the vehicle. The front part (2) is rotated by pivoting the hand about the radioulnar or dorsopalmar axis.

Description

The invention relates to an operating arrangement for a steer-by-wire steering system of a motor vehicle according to the preamble of claim 1. State of the art To translate a driver's steering input, passenger cars currently use steering wheels. By setting an angle on the steering wheel, the driver can determine the position of the rack and pinion, and thus the direction in which the vehicle steers. In conventional vehicles, the steering wheel and wheels are mechanically connected. The rotational movement is transmitted from the steering wheel via the steering column and intermediate steering shaft to a gearbox, which converts the rotational movement into a translational movement of the rack and pinion. This, in turn, rotates the wheels into the desired position. An example of an alternative control element is a joystick, which originates from the gaming sector. Areas where joysticks are used to steer vehicles include aviation and the commercial vehicle sector. The automotive industry's shift towards highly automated driving is leading to new requirements for steering systems. For example, many automakers want the steering wheel to remain stationary when the autopilot takes over vehicle control. This can be achieved by eliminating the mechanical connection between the steering wheel and wheels and instead communicating steering commands via cable (steer-by-wire). Another consideration is that the steering wheel, in its current position, obstructs the driver when using autopilot. When the driver no longer needs to drive, they might, for instance, work on a laptop or read a newspaper while driving. For this purpose, the steering wheel is more of a hindrance; a storage tray, for example, would be more practical. To meet these requirements for vehicles of the future, a new vehicle interior concept including an alternative operating concept is needed. DE 10 2017 209 745 A1 discloses an operating arrangement for a steer-by-wire steering system of a motor vehicle, comprising a mechanical control element located in a passenger compartment of the motor vehicle for inputting a steering request from the driver of the motor vehicle, wherein the control element is rotatably mounted about a predetermined axis of rotation and has a support surface for the driver's hand. The control element is designed so that, when the driver's hand is placed on the support surface, the driver's forearm rotates about the predetermined axis of rotation of the control element. German patent application DE 10 2021 205 924 A1 discloses an operating device for a steer-by-wire steering system, in which several button-like operating elements are arranged on the spherical base. The operating elements are arranged in such a way that a driver can operate them with different fingers of the same hand. A first operating element is associated with the drive system. An acceleration function can be controlled by operating the first operating element. A second operating element is associated with the braking system. A braking function can be controlled by operating the second operating element. A disadvantage of such concepts is the need for two separate buttons. Each button contains all the necessary sensors, electronics, and mechanics, although only one can be used at a time, since in normal operation only one of the functions—accelerator and brake—may be activated simultaneously. Another problem is that the driver can, in principle, press both buttons at the same time, potentially leading to unclear or unintended states. A further disadvantage of button-based concepts is that each button ties up at least one finger. This finger is then unavailable for other tasks, such as holding the control element or for secondary driving functions like the horn, turn signals, or windshield wipers. Since these functions should ideally also be controlled via the alternative control element, it would be advantageous if the accelerator and brake were controlled not by finger movement via buttons, but rather, for example, by hand movement. The object of the invention is therefore to further develop the described operating device, in which the steering request is entered by a rotation of the forearm, in such a way that the driver can accelerate or brake by hand movements without using the fingers or thumb. This frees up the fingers and thumb for other functions. According to the invention, the handle of an alternative control element, which was previously only equipped with input elements for vehicle lateral control (steering), is divided into two parts by a cutting surface. Both parts are connected by a rotation axis that is perpendicular to the cutting surface. The cutting surface and rotation axis are advantageously selected such that the front part of the control element can be ergonomically rotated by pivoting the wrist. The rear part of the control element remains connected to the stationary part of the control element, e.g., via a rotation axis. The driver can steer ergonomically by rotating the forearm. This corresponds anatomically to the supination and pronation of the hand. The invention involves accelerating or braking by pivoting the hand around the radioulnar or dorsopalmar axis. The radioulnar axis enables planar movements of the hand, i.e., palmar flexion and dorsiflexion. The dorsopalmar axis allows for edge movements of the hand, i.e., radial abduction and ulnar abduction. The surface and edge movements of the hand can be performed separately from the supination and pronation of the hand (rotation of the forearm) and can also be blocked by the person, so that holding onto the alternative control element is possible even in dynamic driving situations. Advantageously, the cutting surface is a circle through whose center the axis of rotation passes. This ensures that, regardless of the rotation angle, the butt surfaces of the front and rear parts meet cleanly. Advantageous embodiments and further developments are described in the dependent claims and in the description with reference to the figures. In a further development of the invention, a steering command is entered by rotating the driver's forearm around a rotational axis of the forearm, whereby the predetermined rotational axis (x) of the control element (10) is rotated. The front part is rotated by pivoting the hand around the radioulnar axis. In a further development of the invention, a steering command is entered by rotating the driver's forearm around a rotational axis of the forearm, whereby the predetermined rotational axis (x) of the control element (1) is rotated. The front part is rotated by pivoting the hand around the dorsopalmar axis. In the embodiments described so far, the vehicle is steered by twisting the forearm around a rotational axis of the forearm. Within the scope of the invention, it is also possible to provide a 1-axis joystick with a classic tilting axis for steering. In a further development of the invention, a steering command is entered by tilting the control element to the left or right. The front part is rotated around the radioulnar axis by pivoting the hand. In a further development of the invention, a steering command is entered by tilting the control element to the left or right. The front part is rotated around the dorsopalmar axis by pivoting the hand. In an advantageous further development of the invention, a motor can be arranged on the inventive axis to generate active feedback. The motor can also serve to return the axis to the zero position or for damping. In a further development of the invention, the front part of the control element has a sensor for detecting the angle of rotation, a limitation of the rotational movement in both directions by a mechanical end stop, means for returning to the center position and a damper for damping the rotational movement. One embodiment is briefly explained with reference to the figures. Figure 1 shows an embodiment of the control element according to the invention. Figure 2 shows the interface of the control element according to the invention. Figure 1 shows the control element 1 according to the invention in a first embodiment. A steering command is entered by rotating the driver's forearm around a rotational axis of the forearm, thereby rotating the predetermined rotational axis x of the control element 1. A front part 2 is arranged on the control element 1, which is rotated by pivoting the hand around the dorsopalmar axis. The dorsopalmar axis corresponds to an edge movement of the hand. Figure 2 shows the interface of the control element 1 according to the invention. The interface between the rear and front parts 2 of the control element 1 comprises a sensor 3 for detecting the angle of rotation, a mechanical end stop 4 to limit the rotational movement in both directions, a means 5 for returning to the center position, and a damper 6 for damping the rotational movement. The shaft 7 is supported by ball bearings 8. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2017 209 745 A1

[0006] DE 10 2021 205 924 A1

[0007]

Claims

Operating arrangement for a steer-by-wire steering system of a motor vehicle, comprising a mechanical control element (1) arranged in a passenger compartment of the motor vehicle, wherein the control element (1) is rotatably mounted about a predetermined axis of rotation (x) for inputting a steering request by a driver of the motor vehicle and has a support surface for the driver's hand, characterized in that the control element (1) has a front part (2) which is rotatably mounted about an axis of rotation (y) and serves to accelerate or brake the vehicle, wherein the front part (2) is rotated by pivoting the hand about the radioulnar axis or the dorsopalmar axis. Operating arrangement according to claim 1, characterized in that the input of a steering request is effected by rotating the driver's forearm about a rotation axis of the forearm, wherein the predetermined rotation axis (x) of the control element (10) is rotated; and that the front part (2) is rotated by pivoting the hand about the radioulnar axis. Operating arrangement according to claim 1, characterized in that the input of a steering request is effected by rotating the driver's forearm about a rotation axis of the forearm, wherein the predetermined rotation axis (x) of the control element (1) is rotated; and that the front part (2) is rotated by pivoting the hand about the dorsopalmar axis. Operating arrangement according to claim 1, characterized in that the input of a steering request is made by tilting the control element (1) to the left or right; and that the front part (2) is rotated by pivoting the hand about the radioulnar axis. Operating arrangement according to claim 1, characterized in that the input of a steering request is made by tilting the control element (1) to the left or right; and that the front part (2) is rotated by pivoting the hand about the dorsopalmar axis. Operating arrangement according to one of claims 1 to 5, characterized in that a motor is arranged on the front part (2) of the operating element (1) which generates a return, a damping or a feedback for the driver. Operating arrangement according to one of claims 1 to 6, characterized in that the front part (2) of the operating element (1) has a sensor (3) for detecting the angle of rotation, a limitation of the rotational movement in both directions by a mechanical end stop (4), means (5) for returning to the center position and a damper (6) for damping the rotational movement.

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