Controller for controlling a floor cleaning device, floor cleaning device and nozzle thereof

1 . A controller for controlling a floor cleaning device that comprises a nozzle configured to contact a floor, a rotatable brush arranged at the nozzle, a brush motor configured to drive the brush to rotation, and a nozzle detector configured to detect whether the nozzle is lifted from the floor,

the controller being configured to:

provide control signals to the brush motor to control the rotation of the brush;

receive sensor data from the nozzle detector that indicates whether the nozzle is lifted from the floor;

control the control signals to decrease an upper threshold of a parameter related to a torque of the brush motor, based on the sensor data indicating that the nozzle is lifted from the floor, to decrease a maximum current or voltage drawn by the brush motor.

2 . The controller of claim 1 , wherein the controller is configured to, via the control signals:

limit the parameter related to the torque of the brush motor to a first upper threshold, based on the sensor data indicating that the nozzle contacts the floor; and

limit the parameter related to the torque of the brush motor to a second upper threshold, based on the sensor data indicating that the nozzle is lifted from the floor, the second upper threshold being smaller than the first upper threshold.

3 . The controller of claim 2 , wherein the controller is configured to:

receive parameter data indicating a value of the parameter related to the torque of the brush motor; and

via the sensor signals, turn off the brush motor or to reduce a brush speed of the rotatable brush, based on the sensor data indicating that the nozzle is lifted from the floor and the parameter data indicates that the parameter related to the torque of the brush motor reaches the second upper threshold and/or is kept at the second upper threshold for a predetermined amount of time.

4 . The controller of claim 1 , wherein the controller is configured to:

receive parameter data indicating a value of the parameter related to the torque of the brush motor;

detect an obstruction of the nozzle based on the parameter related to the torque of the brush motor; and

turn off the brush motor or reduce a brush speed of the rotatable brush responsive to detecting an obstruction of the nozzle.

5 . The controller of claim 1 ,

wherein the parameter related to the torque of the brush motor is a brush motor current drawn by the brush motor and/or a brush motor voltage of the brush motor.

6 . A nozzle for a floor cleaning device, the nozzle comprising:

a rotatable brush,

a brush motor configured to drive the brush to rotation,

a nozzle detector configured to detect whether the nozzle contacts a floor or is lifted from the floor; and

the controller of claim 1 .

7 . The nozzle of claim 6 ,

wherein the nozzle detector comprises a pressure sensor configured to detect a pressure signal indicative of a pressure within the floor cleaning device, wherein the nozzle detector is configured to determine based on the pressure signal that the nozzle is lifted from the floor.

8 . The nozzle of claim 6 ,

wherein the nozzle detector comprises a current detector configured to detect a current signal indicative of a current drawn by an underpressure generation unit, wherein the nozzle detector is configured to determine based on the current signal that the nozzle is lifted from the floor.

9 . The nozzle of claim 6 ,

wherein the nozzle detector comprises an optical sensor configured to detect an optical signal, wherein the nozzle detector is configured to determine based on the optical signal that the nozzle is lifted from the floor.

10 . The nozzle of claim 6 ,

wherein the nozzle detector comprises a switch arranged at the nozzle, wherein the nozzle detector is configured to determine that the nozzle is lifted from the floor if the switch is actuated.

11 . The nozzle of claim 6 ,

wherein the nozzle detector comprises an orientation sensor configured to detect an orientation signal indicative of a spatial orientation of the nozzle, wherein the nozzle detector is configured to determine based on the orientation signal that the nozzle is lifted from the floor.

12 . The nozzle of claim 6 ,

further comprising a brush speed sensor configured to detect a brush speed of the rotatable brush, wherein the controller is configured to control the rotation of the brush based on the detected brush speed.

13 . A floor cleaning device, comprising:

a nozzle configured to contact a floor;

a rotatable brush arranged at the nozzle;

a brush motor configured to drive the brush to rotation;

a nozzle detector configured to detect whether the nozzle contacts the floor or is lifted from the floor; and

the controller of claim 1 .