The invention relates to a rotary control device for a vehicle comprising a user interface surface that is embodied to rotate with respect to a housing of the device around a rotational axis of the device, further comprising a sensor unit for monitoring the orientation and/or rotational movement of the user interface surface with respect to the housing, a processing unit, and a communications interface for transmitting control signals according to an output from the processing unit, said output being generated by the processing unit on the basis of sensor data from the sensor unit, wherein the rotary control device further comprises a magnetorheological actuator, wherein the magnetorheological actuator comprises a rotational element that is mechanically connected to the user interface surface and serves to interact with a magnetorheological fluid of the magnetorheological actuator, and wherein the magnetorheological actuator comprises an assembly for generating and/or manipulating properties of a magnetic field acting on the magnetorheological fluid such that the magnetorheological actuator serves to modulate torque transmission between the user interface surface and the housing.

Haptic interfaces for control are known for example from the European patent publication EP2065614A1 , wherein an assembly for manipulating properties of a magnetic field is disclosed for the purpose of modulating the torque transfer between a rotational element and a housing of the haptic interface.

The object of the invention is to introduce an improved rotary control device.

The object of the invention is achieved by a rotary control device defined by the subject matter of the independent claim. The dependent claims and the description define advantageous embodiments of the system.

The object is therefore achieved by a rotary control device for a vehicle comprising a user interface surface that is embodied to rotate with respect to a housing of the device around a rotational axis of the device, further comprising a sensor unit for monitoring the orientation and/or rotational movement of the user interface surface with respect to the housing, a processing unit, and a communications interface for transmitting control signals according to an output from the processing unit, said output being generated by the processing unit on the basis of sensor data from the sensor unit, wherein the rotary control device further comprises a magnetorheological actuator, wherein the magnetorheological actuator comprises a rotational element that is mechanically connected to the user interface surface and serves to interact with a magnetorheological fluid of the magnetorheological actuator, and wherein the magnetorheological actuator comprises an assembly for generating and/or manipulating properties of a magnetic field acting on the magnetorheological fluid such that the magnetorheological actuator serves to modulate torque transmission between the user interface surface and the housing, wherein the assembly is embodied to generate and/or manipulate the properties of the magnetic field according to 10 governing signals output from the processing unit when the user interface surface is in an orientation for selecting a drive operation mode and in accordance with a status signal received by the device indicating that a drive unit of the vehicle is in an active or inactive state, respectively.

A position of the user interface surface in the sense of the invention refers to the placement of the user interface surface within a plane spatially displaced from the housing of the device by a specified distance. An orientation of the user interface surface in the sense of the invention refers to a rotational displacement of the user interface surface around the rotational axis of the device by a specific degree of rotation with respect to an initial setting of the user interface surface with reference to the housing.

The magneto-rheological fluid defines the behavior of the rotary control device. To this end, a voltage supplied to the assembly is varied to induce a surrounding magnetic field that changes the viscosity of the fluid. Depending on the magnetic field, in particular depending on properties of the magnetic field such as intensity and/or direction, the MRF can vary between liquid and solid state, which can be controlled very accurately. In a fluid state, MRF transfers little to no torque between the rotational element and the housing. However, as the viscosity increases and the fluid approaches a solid state, the sheer forces within the fluid and between the fluid and the rotational element as well as between the fluid and the housing, or a component attached fixedly to the housing, increases. This leads to an increasing torque transfer between the user interface surface and the housing.

The device can be used to select an operation mode of the vehicle, which is for example a forwards drive operation mode wherein torque is transferred from a drive unit of the vehicle in order to propel the vehicle in a forwards direction, a reverse drive operation mode wherein torque is transferred from a drive unit of the vehicle in order to propel the vehicle in a reverse direction, a neutral operation mode wherein no torque is transferred from a drive unit of the vehicle, a park operation mode where a torque transmission unit attached to the drive unit of the vehicle is mechanically blocked, or another operation mode.

When a position and/or orientation of the user interface surface remains constant in the absence of a force applied the device from an external source, then this position and/or orientation of the user interface surface can be referred to as a stable position. On the other hand, when the user interface surface does not remain in a certain position or orientation, because for example a mechanism of the device applies a force internally, then this position and/or orientation can be referred to as being non-stable.

A safety relevant function of the vehicle in the sense of the invention can be for example the selection of an operation mode of the vehicle, steering, accelerating or braking the vehicle. A non-safety function of the vehicle can be for example navigation or control of a multimedia interface.

A communications pathway in the sense of the invention can be for example a hardline for transferring data such as a databus and/or a wireless data transmission channel. In many modern street vehicles, a CAN-databus is a preferred type of communications pathway.

The user interface surface, or knob, in the sense of the invention can comprise the outer surface of a ring shaped and/or half shell shaped structure, which is accessible to an operator, i.e. user, of the vehicle. The user interface surface can further comprise a construction underlying the outer surface of the user interface surface.

In an embodiment of the control device the device is embodied to transmit control signals for deactivating or activating the drive unit in the case where the user interface surface is rotated a predetermined amount around the rotational axis to reach an 10 orientation while the 10 governing signals are being output to modulate the torque transfer.

In an embodiment of the control device the processing unit is embodied to output the 10 governing signals that serve to cause the assembly to manipulate the properties of the magnetic field such that a braking force progression is formed along the rotational pathway from the orientation of the user interface surface for selecting a drive operation mode to an 10 orientation, and in that the braking force progression from the orientation for selecting the drive operation mode to the 10 orientation varies from the braking force progression formed along a rotational pathway of the user interface surface between the orientation for selecting a drive operation mode and a different orientation for selecting a different operation mode of the vehicle.

In an embodiment of the control device the 10 orientation can only be reached by a rotational movement of the user interface surface in a rotational direction opposite to a rotational direction in which the user interface surface must be rotated to a reach an orientation for selecting a different operation mode when the user interface surface is in an orientation for selecting a drive operation mode of the vehicle.

In an embodiment of the control device the processing unit is embodied to output governing signals such that the braking force progression formed along the rotational pathway from the orientation for selecting the drive operation mode of the vehicle to the 10 orientation corresponds to a braking force progression defined by a mechanical system requiring a rotational movement for igniting or turning off an engine in a motor vehicle. In an embodiment of the control device the processing unit is embodied to output 10 governing signals such that the braking force progression formed along the rotational pathway from the orientation for selecting a drive operation mode to the 10 orientation comprises a first partial pathway wherein braking force continually increases, a second partial pathway wherein the braking force continually decreases and a third partial pathway wherein the braking force continually increases to a value greater than the value of the braking force reached within the first partial pathway.

In an embodiment of the control device the device comprises a torque sensor, and in that the device is embodied to only transmit the control signals for deactivating or activating the drive unit of the vehicle when an operator applies a predetermined amount of torque to the user interface surface while in the 10 orientation.

In an embodiment of the control device when the user interface surface is in the ignition orientation and a predetermined amount of torque is applied to the user interface surface, that the processing unit is embodied to output governing signals such that an ignition braking force progression is formed along an restart rotational pathway extending beyond the rotational pathway from the orientation for selecting the drive operation mode to the 10 orientation in the same rotational direction, and the processing unit is embodied to output 10 governing signals for governing the assembly such that the assembly manipulates the magnetic field acting on the fluid to fluctuate, thereby simulating a vibrational haptic feedback along the restart rotational pathway to the user applying torque to the user interface surface at the moment of fluctuation.

In an embodiment of the control device the rotational element comprises a chamber containing the magnetorheological fluid, and in that a static element is provided, which is fixedly arranged with respect to the housing and arranged at least partially within the chamber, such that the torque transmission between inner surface of the chamber of the rotational element and the static element is dependent on the properties of a magnetic field.

In an embodiment of the control device the rotational element is embodied to rotate within a chamber of the actuator containing the magnetorheological fluid, said cham- ber being fixedly arranged with respect to the housing, such that the torque transmission between the rotational element and an inner surface of the chamber is dependent on the properties of a magnetic field.

Certain embodiments of the invention will next be explained in detail with reference to the following figures. They show:

Fig. 1 a schematic diagram of an embodiment of the inventive rotary control device; and

Fig. 2 a schematic diagram of an operation mode selection sequence of an embodiment of the inventive rotary control device.

Fig. 1 shows a schematic diagram of an embodiment of the inventive rotary control device 1 having a user interface surface 3, which can be moved and rotated by a user or operator of a vehicle. The user interface surface can be rotated around a rotational axis 7 of the device 1 to various orientations, for example for selecting operation modes of a vehicle. The user interface surface 3 can furthermore be moved by a user or operator of the vehicle between a first, second and third position P1 , P2, P3.

The device 1 comprises a housing 5, which at least partially encloses a processing unit 11 mounted on a substrate 15, which is a printed circuit board. The processing unit 11 is connected to a communications interface 13. Via the communications interface 13 signals such as control signals Ts can be transmitted and received. The processing unit 11 is further connected to a sensor unit 9 which serves to monitor the rotational movement and/or orientation of the user interface surface with respect to the housing 5. The sensor unit 9 transmits sensor data Ds to the processing unit 11 and on the basis of this sensor data Ds, the processing unit 11 can generate control signals to transmit via the communications interface 13.

The device further comprises an assembly 17 for generating and manipulating a magnetic field in a chamber 19 of the housing 5. The chamber contains a magne- torheological fluid 21 also known as MRF. Positioned partially within the chamber is a rotational element 23. The rotational element 23 is mechanically connected to the user interface surface 3 and rotates with the rotation of the interface3.

Corresponding to changes in properties of the magnetic field caused by the assembly 17, such as field strength and direction, the magnetorheological fluid 12 varies in viscosity so to speak. Therefore, in a corresponding way, the fluid transfers more or less torque between the user interface surface 3 and the housing 5 of the device 1 . This is due to the changing sheer forces within the fluid and between the fluid and the chamber wall. Since the housing 5 of the device is generally fixedly mounted within the vehicle, the assembly can be considered to modulate a sort of braking force acting on the user interface surface 3. Such systems comprising MRF 21 in a chamber 19, rotational elements 23, and assemblies 17 for manipulating the magnetic field within the chamber 19 are often referred to as MRF-Actuators. The processing unit 1 1 is embodied to output governing signals for controlling the assembly 17. The assembly 17 can, for example, be driven by a circuit on the substrate 15 feeding the assembly 17 with a pulsed width modulated (PWM) current or voltage in accordance with the governing signals from the processing unit 1 1 .

The device further comprises a servo actuator 25 which engages with the rotational element 23 and can therefore apply torque to the user interface surface 3.

Fig. 2 shows a schematic diagram of an operation mode selection sequence of an embodiment of the inventive rotary control device. The user interface surface 3 can be rotated around the axis of rotation 7 in order to reach orientations for selecting various operation modes of the vehicle. When a forwards operation mode D is selected, or relatedly, when the orientation of the user interface surface is such that a control signal is transmitted from the device for selecting this operation mode, then an operator of the vehicle is provided with additional optional orientations, for example in order to deactivate the drive unit of the vehicle. Many modern street vehicles have drive units comprising motors that run on fossil fuels. It can therefore be advantageous to deactivate such a motor when the vehicle is at rest, at a stop light for example. Depending on whether the drive unit is activated or deactivated, the operator can rotate the user interface to the 10 orientation in order to deactivate or activate the drive unit, respectively. At the same time, the processing unit 11 of the device 1 can output IO governing signals such that the MRF actuator of the device provides a braking force along the rotational pathway of the user interface surface 3. The MRF actuator can for example manipulate the magnetic field such that the braking force is removed at intervals and again increased to a predetermined value at intervals. This manipulation of the magnetic field causes the user interface surface to move incrementally at intervals, which can be interpreted by the operator as a vibration.

Further operational modes such a sport, comfort and Eco can also be selected by rotating the user interface surface to the corresponding orientation.

Reference Characters

1 Rotary control device

3 user interface surface

5 housing

7 rotational axis

9 sensor unit

11 processing unit

13 communications interface

15 substrate/PCB

17 assembly for generating/manipulating magnetic field

19 chamber

21 magnetorheological fluid

23 rotational element

25 servo actuator

X1 first direction

X2 second direction

P1 first position

P2 second position

P3 third position