DAMP CLEANING OF A FLOOR SURFACE

Description

[0001] The present invention relates to a floor cleaning robot. In particular, the invention relates to the control of a robot configured to wet-clean a floor surface.

[0002] A cleaning robot is designed to clean a floor surface. This can be done either dry cleaning, for example, by vacuuming, or wet cleaning, in which a cleaning fluid is distributed over the floor surface to loosen or bind dirt. The fluid can then be largely reabsorbed by the robot.

[0003] From the publications WO 2008 / 007830 A1, WO 2020 / 226-426 A2, CN 114 431 785 A and AU 2018 102 050 A4, methods for controlling cleaning robots are known which offer wet cleaning in addition to dry cleaning.

[0004] The cleaning robot has a drive wheel and is designed to travel a predetermined route across the floor. A cleaning device for wet cleaning the floor is typically located behind the drive wheel, so that no wheel marks are left on the cleaned surface. In practical use, however, it is often unavoidable for the cleaning robot to re-drive over an area it has already cleaned, leaving visible marks from the drive wheel on the cleaned surface.

[0005] DE 10 2018 200 719 A1 proposes optically analyzing the condition of a surface that a cleaning robot is to travel on. The cleaning robot can then be controlled based on the analysis results.

[0006] DE 10 2014 111 217 A1 relates to a control system for a floor-cleaning robot such that a first and then a second cleaning step is performed on the floor surface. The first step may, in particular, comprise dry cleaning and the second, wet cleaning.

[0007] US 2014 / 0 230 179 A1 describes a method for controlling a robot in which a moisture level of a section of the floor surface to be traveled over is determined.

[0008] US 2021 / 0 068 524 A1 describes, among other things, a robot that includes sensors that detect the condition of the floor to be cleaned.

[0009] DE 10 2012 108 008 A1 describes a suction device that has a sensor for detecting properties of the environment of the suction device.

[0010] One object underlying the present invention is to provide an improved technology for high-quality cleaning of a floor surface using a cleaning robot. The invention achieves this object by means of the subject matter of the independent claims. Subordinate claims specify preferred embodiments.

[0011] According to a first aspect of the present invention, a method for controlling a robot for wet cleaning a floor surface comprises steps of traveling over the floor surface and wet cleaning the traveled over floor surface. A moisture level of a section of the floor surface to be traveled over by the robot is determined based on a previous cleaning of the section; and the section is only traveled over if the moisture level is below a predetermined threshold value. A route leading across the floor surface is planned such that a processed section is only traveled over when its moisture level is below the threshold value.

[0012] This ensures that the robot doesn't leave marks on wet or damp sections of the floor, which could be caused by a drive wheel or support wheel, for example. The floor can be left clean and streak-free.

[0013] Preferably, the section to be traveled has previously been cleaned by the robot. The robot may have wet-cleaned the section, so any moisture in the section is caused by the robot itself. By avoiding driving on the wet section, the drive wheel can remain clean and dry and have improved grip on the ground. This allows the robot to navigate more accurately or travel faster.

[0014] The moisture level of the section can be determined using a sensor attached to the robot. The sensor can be optical, capacitive, or resistive, for example. The sensor can also be used to identify a section to be traveled that is moist for reasons other than the robot's previous processing. To check the moisture level, the robot can slow down or stop. In other areas, it can maintain its usual processing speed without measuring.

[0015] According to the invention, the moisture level of a section is determined based on previous cleaning of that section. The robot can record in an internal memory which sections of the floor it has already wet-cleaned. Driving over such a section can then be prevented.

[0016] In a further preferred embodiment, the moisture level of the section is determined based on the duration between the previous cleaning and the planned travel. For example, a section that was wet-cleaned approximately five minutes ago can be determined to be sufficiently dry. However, a section that was wet-cleaned just a few seconds ago can be determined to be too wet for the robot to travel over. If no other option is available, the robot can stop and wait until the section has had sufficient time to dry. The predetermined duration can be set based on an ambient temperature and / or humidity.

[0017] The moisture level of the section can also be determined based on the condition of the floor surface on the section to be traveled. For example, a marble tile may dry faster than parquet or linoleum. Other possible substrates include a wooden floor, which can be untreated, oiled, or sealed; cork, screed, concrete, or glazed or unglazed tiles. The surfaces of the substrates can each be treated or coated differently.

[0018] In a similar embodiment, the time interval to be observed between the previous cleaning and the planned travel can be determined depending on the condition of the floor surface. Different predetermined conditions can each be assigned a predetermined duration. This duration can be determined depending on an environmental influence, in particular humidity or ambient temperature.

[0019] In yet another embodiment, the moisture level of the section is determined based on a previously performed wet cleaning in that section. This allows consideration of when and how the robot itself moistened the section. For example, if the robot cleans the section multiple times or particularly intensively, a longer time can be assumed until the moisture level is sufficiently low for driving over it.

[0020] According to the invention, a route across the floor surface is planned in such a way that a cleaned section is only accessed when its moisture level is below the threshold. In other words, the route can be guided in such a way that the predetermined time between cleaning a section and a subsequent access is maintained. Between these two times, the robot can clean another section of the floor surface.

[0021] It should generally be noted that a section of the floor surface cleaned by the robot can only be considered wet if the robot has cleaned the section with a wet mop. If, for example, the robot does not use a mop on the section or only cleans the section with a dry mop, for example, using a vacuum cleaner, the cleaned section can be considered unchanged or dry.

[0022] According to a further aspect of the present invention, a robot for wet cleaning a floor surface comprises a drive device for traveling over the floor surface; a cleaning device for wet cleaning a traveled section of the floor surface; and a processing device. The processing device is configured to determine a moisture level of a section of the floor surface to be traveled over by the robot based on a previous cleaning of the section and to travel over the section only if the moisture level is below a predetermined threshold value. A route leading across the floor surface is planned in such a way that a processed section is, if possible, only traveled over when its moisture level is below the threshold value.

[0023] The processing device can be configured to carry out a method described herein in whole or in part. For this purpose, the processing device can comprise a programmable microcomputer or microcontroller, and the method can be in the form of a computer program product with program code means. The computer program product can also be stored on a computer-readable data carrier. Features or advantages of the method can be transferred to the device, or vice versa.

[0024] The robot can also be configured for dry cleaning of the floor surface. In one embodiment, the robot can first clean the floor surface dry and then wet clean. Dry cleaning of the floor surface is generally largely independent of wet cleaning, so only wet cleaning is described herein.

[0025] The processing device can determine the moisture level of the section to be traveled based on a previous wet cleaning of the section. In a further embodiment, which can be combined with this procedure, the robot comprises a sensor for determining the moisture level of the section to be traveled. The sensor can comprise, for example, an infrared sensor, a camera, a resistive sensor, or a capacitive sensor. Preferably, the sensor is configured to scan a section of the floor surface located directly in front of the robot to determine its moisture level. The scanning can be performed without contact.

[0026] The invention will now be described in more detail with reference to the accompanying figures, in which: Figures 1 and 2 show a robot for cleaning a floor area; Figure 3 shows a flowchart of a method for controlling a robot; and Figure 4 shows an exemplary occupancy map for a cleaning robot.

[0027] Figures 1 and 2 show an exemplary robot 100 for cleaning a floor area 105. In Figure 1 is a bottom side of the robot 100 and in Figure 2 A longitudinal section is shown. A block arrow indicates a forward direction of travel.

[0028] The robot 100 has at least one drive wheel 110, a first cleaning device 115, an optional second cleaning device 120 and a further optional third cleaning device 125.

[0029] The first cleaning device 115 is preferably located behind the drive wheel 110 with respect to the usual direction of travel; the second and / or third cleaning devices 120, 125 can also be located behind or in front of it. Optionally, a support wheel or a skid is provided in front of the first cleaning device 115. The arrangement is preferably selected such that no elements are attached to the robot 100 behind the first cleaning device 115 that could touch the floor surface 105 or impair an already achieved cleaning result of the floor surface 105.

[0030] The first cleaning device 115 is configured to wet-clean the floor surface 105. For this purpose, a liquid container can be carried on board the robot 100, which contains liquid that is distributed on the floor surface 105 in the area of ​​the first cleaning device 115. An element of the first cleaning device 115, which is configured to be guided along the floor surface 105, for example, a fleece or a fabric, can additionally be moved, for example, in a circular, linear, or cycloidal manner. In one embodiment, the first cleaning device 115 can be activated or deactivated. To deactivate, it can be lifted from the floor surface 105, and to activate, it can be lowered onto it.

[0031] The optional second cleaning device 120 is preferably configured for dry cleaning of the floor surface 105. In the illustrated embodiment, the second cleaning device 120 comprises a brush roller, which can optionally be assisted by a suction device similar to a vacuum cleaner. The optional third cleaning device 125 comprises a brush or broom rotatable about a vertical axis, which can be used, particularly in conjunction with the second cleaning device 120, to dry clean the floor surface 105 as far as an obstacle, leaving as few gaps as possible.

[0032] A processing device 130 is configured to control the robot 100 on the floor surface 105 and to appropriately deploy the cleaning devices 115 to 125. In one embodiment, the floor surface 105 is first cleaned dry using the second and / or third cleaning device 120, 125 and only then wet using the first cleaning device 115.

[0033] A first sensor 135 can be provided to scan an environment, which can comprise, for example, a camera or a LIDAR sensor. Other possible sensors 135 include a radar sensor, an inertial platform, a gyroscope, or a rotary encoder on a drive wheel. Multiple first sensors 135 can also be provided. The processing device 130 can determine a position of the robot 100 and that of an obstacle on the floor surface 105 based on scans from the first sensor 135. Optionally, the processing device 130 can also determine a route for traveling over the floor surface 105 based on the scans.

[0034] Preferably, a second sensor 140 is provided, which is configured to determine the moisture level of a section of the floor surface 105 that lies in front of the robot 100 in the direction of travel. For this purpose, the second sensor 140 is preferably arranged in front of the drive wheel 110. The second sensor 140 can, for example, comprise an infrared sensor, a camera, a resistive sensor, a capacitive sensor, a humidity sensor, a gloss sensor, or an optical sensor that scans the floor surface, similar to what is known from a computer mouse.

[0035] Depending on the measuring principle, the second sensor 140 can, for example, be attached to a front boundary of the robot 100, with a scanning area typically directed obliquely forward toward the floor surface 105. In another embodiment, the second sensor 140 can be arranged in a lower region of the robot 100, for example, in front of or behind the second cleaning device 120. In general, the sensor 140 should preferably be attached to the robot 100 in such a way that it can determine a still wet section of the floor surface 105 even before an element of the robot 100 has left traces on the wet section. The second sensor 140 is therefore preferably used in front of the drive wheel 110 and all possible support wheels, skids, or processing devices 120, 125 that could leave a trace on a wet section of the floor surface 105.

[0036] Figure 3shows a flowchart of a method 300 for controlling a robot 100. The method 300 can be carried out in particular by means of a processing device 130 on board the robot 100.

[0037] In a step 305, a route for the robot 100 can be determined. The route preferably leads over a floor surface 105 in such a way that free areas can be cleaned seamlessly when the robot 100 travels over it, wherein the length of a distance traveled on the floor surface is preferably minimized. The route can also be optimized with respect to other parameters. In one embodiment, the route is determined such that it crosses as infrequently as possible. For this purpose, a section of the floor surface 105 that has already been worked on can be avoided or subjected to an increased cost function. More preferably, the route runs in a meandering manner. In one embodiment, the aim is for the route to comprise a series of parallel paths so that the floor surface 105 can be cleaned as completely and streak-free as possible.

[0038] In a step 310, cleaning of the floor surface 105 can be performed. For this purpose, the robot 100 can move along the specified route on the floor surface 105 and use the first cleaning device 115 to perform a wet cleaning. A dry cleaning can occur simultaneously or in the same work step, or it can have already been performed at an earlier time.

[0039] In a step 315, a cleaned section of the floor area 105 can be entered into an occupancy map. An exemplary occupancy map is shown with reference to Figure 4 described in more detail.

[0040] In step 320, it can be determined whether the predetermined route crosses a section of the route that has already been cleaned. In particular, it can be checked whether a section of the floor area 105 located directly in front of the robot 100 in the direction of travel has already been cleaned. This determination can be made based on the occupancy map.

[0041] If the section has not yet been cleaned, you can continue with step 310.

[0042] Otherwise, if a previously cleaned section lies ahead of robot 100, a check can be made in step 325 to determine whether an alternative route is possible that does not cross a previously cleaned section. If this is the case, the route can be determined or adjusted accordingly, and method 300 can continue with step 310.

[0043] Otherwise, if no alternative route can be determined, a step 330 can determine whether the section to be traveled has already been cleaned by the robot 100 for more than a predetermined period. If this is the case, the section can be traveled without the risk of leaving traces on the section. In this case, the method 300 can continue with step 310.

[0044] Otherwise, if the last cleaning was performed recently, a check can be carried out in step 335 to determine whether the section to be traveled over is damp. For this purpose, the section can be checked for its dampness using the second sensor 140. If the dampness is below a predetermined threshold, the section can be traveled over, and the method can continue with step 310. If it is determined that the measured dampness of the section does not match the dampness determined based on the drying time, the predetermined duration can be adjusted. In doing so, the condition of the floor surface 105 on the section can be taken into account.

[0045] Otherwise, if the section to be traveled is still too wet, it is possible to wait in a step 340 until the humidity level of the section has fallen below the predetermined threshold value or the predetermined time has elapsed.

[0046] It should be noted that the steps of the method illustrated are not necessarily carried out in the described order, and that not all of the steps mentioned need to be implemented in method 300. Determining the moisture level of a section of the floor surface 105 with respect to the time elapsed since the last wet cleaning can follow in addition to or alternatively to a metrological determination of the moisture level using the second sensor 140. Determining an alternative route can also only occur when one or more tests indicate that the moisture level of the section to be traveled is too high. It is preferred that waiting in step 340 is the least frequently chosen alternative when a section of the floor surface 105 to be treated has an excessive moisture level.

[0047] Figure 4shows an exemplary occupancy map 400 that can be used for navigation or route determination for the robot 100. By way of example, three levels 405, 410, and 415 are provided, each covering the same physical area but representing different information. The occupancy map 400 is divided into a predetermined grid of fields in all levels 405 to 415, each corresponding to a section of the floor area 105. For better understanding of the illustration, a vertical, dashed line is drawn that vertically connects three exemplary, corresponding fields of the levels 405-415. The occupancy map 400 can, for example, depict a household or a room of a household in which the robot 100 is to be used.

[0048] A route 420 is shown in the first level 405. The route 420 typically runs in a meandering fashion from a predetermined starting point across the floor surface 105, so that each section can be traversed and cleaned by the robot 100 at least once, and preferably no more than once. If different cleaning runs are to be performed, for example, a dry and a wet cleaning run, a route 420 for the dry cleaning run can be determined using any known method. The illustrated route 420 for the wet cleaning run is preferably determined such that it includes as few intersection points with itself as possible. Other optimization objectives can also be applied.

[0049] The second level 410 contains obstacles 425, which may include, for example, a wall, a piece of furniture, or a deep-pile carpet. Optionally, a distinction can be made between an obstacle 425 that can be driven over but is not to be cleaned and an obstacle that is not to be driven over. While driving over an obstacle 425 that is not to be cleaned, the first cleaning device 115 can be deactivated.

[0050] The third level 415 can contain binary values ​​indicating whether the robot 100 has already visited the corresponding section of the floor area 105 in the current cleaning run. If this is the case, it is referred to as a crossing route. Before the cleaning run, all fields can be set to a predetermined value.

[0051] In the illustrated, more refined embodiment, the third level 415 contains an entry in each of the individual fields indicating a time at which the corresponding section of the floor surface 105 was last wet-cleaned by the robot 100. Unoccupied fields can also be initialized with a predetermined value indicating that the section has not yet been cleaned in the current cleaning run. When traveling over the floor surface 105, a field of the third level 415 corresponding to a cleaned section of the floor surface 105 can be provided with an entry indicating a current time. The entry can, in particular, include a timestamp, which optionally also contains a date.

[0052] To generate the timestamp, a timer 430 can be carried on board the robot 100. The current timestamp can be entered into the corresponding field of the third level 415 upon entering the section, during processing, or upon leaving the section. In the illustrated embodiment, timestamps in the range from 1 to 6 are entered purely by way of example. Time increments between consecutive timestamps can, for example, be one second each or another predetermined value.

[0053] If the robot 100 is about to travel over a section of the floor area 105 that corresponds to an already occupied field of the third level 415, the time elapsed between the previous processing of the section and the current time can be determined by subtracting the time recorded in the field from the current time of the timer 430. In the present example, the section of the floor area 105 to be traveled over was wet-cleaned 8 - 1 = 7 time steps ago.

[0054] In one embodiment, a time period is predetermined that is typically sufficient to allow a wet-cleaned section of the floor surface 105 to dry again. If this time period is seven or less in the present example, the robot can continue to follow route 420. However, if the predetermined time period is eight or more, the robot 100 must wait until the predetermined drying time has been reached. In the example shown, it cannot set up an alternative route 420 because there are obstacles 425 to its right and left, and a field behind it has also already been wet-cleaned.

[0055] Once the robot 100 has completed its cleaning run of the floor area 105, each field in the occupancy map 400 can contain either an obstacle 425 in the second level 410 or a timestamp in the third level 415. The values ​​of the third level 415 can be deleted after the cleaning run, set to a predetermined value, or retained for a subsequent cleaning run. The timer 430 preferably runs continuously, even between cleaning runs. Reference symbol

[0056] 100Robot 105Floor surface 110Drive wheel 115First cleaning device, wet 120Second cleaning device, dry 125Third cleaning device, dry 130Processing device 135First sensor, scanning an environment 140Second sensor, determining a humidity level 300 Procedure 305 Determine route 310 Carry out cleaning 315 Enter cleaned section on occupancy map 320 Route crosses cleaned section? 325 Alternative route possible? 330 Has it been long enough since cleaning? 335 Is the floor damp? 340 Wait 400 Occupancy map 405 First level: Route 410 Second level: Occupancy 415 Third level: Cleaning times 420 Route 425 Obstacle 430 Timer

Claims

1. Method (300) for controlling a robot (100) for the damp cleaning of a floor surface (105), wherein the method (300) comprises the following: - travelling (310) over the floor surface (105) and damp cleaning (310) of a section of the floor surface (105) that has been travelled over; - wherein a degree of dampness of a section of the floor surface (310) to be travelled over by the robot (100) is determined (330, 335); and - the section is only travelled over (310) if the degree of dampness lies below a predetermined threshold value, characterised in that - a degree of dampness of the section is determined (330) on the basis of a past cleaning of the section, and - a route (420) leading over the floor surface (105) is planned in such a manner that a treated section, where possible, is only travelled over if its degree of dampness lies below the threshold value.

2. Method (300) according to claim 1, wherein the section to be travelled over has been previously treated (310) by the robot (100).

3. Method (300) according to claim 1 or 2, wherein a degree of dampness of the section is determined (335) by means of a sensor (140) attached to the robot (100).

4. Method (300) according to one of the preceding claims, wherein the degree of dampness of the section is determined (330) on the basis of a duration between the past cleaning and the planned travelling-over.

5. Method (300) according to one of the preceding claims, wherein the degree of dampness of the section is determined on the basis of a nature of the floor surface (105) in this section.

6. Method (300) according to one of the preceding claims, wherein the degree of dampness of the section is determined on the basis of a damp cleaning previously performed in this section.

7. Robot (100) for the damp cleaning of a floor surface (105), wherein the robot (100) comprises the following: - a drive facility (110) for travelling over the floor surface (105); - a cleaning facility (115) for the damp cleaning of a section of the floor surface (105) that has been travelled over; and - a processing facility (130), which is configured to determine a degree of dampness of a section of the floor surface (105) to be travelled over by the robot (100); and - to only travel over the section if the degree of dampness lies below a predetermined threshold value, characterised in that - a degree of dampness of the section is determined (330) on the basis of a past cleaning of the section, and - a route (420) leading over the floor surface (105) is planned in such a manner that a treated section, where possible, is only travelled over if its degree of dampness lies below the threshold value.

8. Robot (100) according to claim 7, further comprising a sensor (140) for determining the degree of dampness of the section to be travelled over.