Method for humidifying a cleaning pad

Abstract

A method for moistening a cleaning pad (5) of a mobile, self-propelled device is described, comprising a storage tank (9) with cleaning fluid and tank outlets and an air pump or air blower, wherein the air pump or air blower is operated during a cleaning run of the device in such a way that, depending on the current fill level of the cleaning fluid, an air delivery rate of the air pump or air blower is regulated in such a way that volume flow changes from the tank outlets are compensated, wherein the current fill level of the cleaning fluid is estimated by the device on the basis of the control of the air pump or air blower.

Description

[0001] The invention relates to a method for moistening a cleaning pad of a mobile, self-driving device, in particular a floor cleaning device such as a mopping robot, a mobile, self-driving device, a computer program product and a computer-readable data carrier.

[0002] Floor cleaning robots are designed to relieve users of recurring tasks such as sweeping, vacuuming, and mopping, or at least make them easier. Besides regular cleaning, users particularly value a visibly clean result. No dust or stains should be visible on the floors after the robot has finished cleaning. Combination vacuum and mop devices, which have a dry cleaning unit (sweeping and vacuuming) and a wet cleaning unit, are advantageous for this type of cleaning. For wet cleaning, the robots use textile cleaning pads or rollers that are moistened with water (or a cleaning fluid). During a cleaning cycle, the robot pumps water or cleaning fluid from its reservoir onto the cleaning pads (usually at regular intervals).If this moistening process is carried out unevenly over the duration of a cleaning job, the moisture level of the cleaning pad can fluctuate, which can lead to a reduction in the quality of the wiping results and, in addition to a reduction in the hygienic aspects of the cleaning, can also lead to an optical impairment of the results.

[0003] Cleaning robots often automatically moisten their cleaning pads at the beginning and / or during a wet cleaning process. Various approaches have been developed for the automatic moistening of the cleaning pads, with the water or cleaning fluid being supplied by the robot or its service station. In most wet-cleaning robots, the cleaning pads are moistened by dispensing water from a reservoir on the robot (e.g., via a pump), with water dripping onto the top of the cleaning pad. One option is the use of peristaltic or diaphragm pumps, which draw cleaning fluid directly from the reservoir and deliver it to the cleaning pads.

[0004] Another way to control the liquid dispensing is to use an air pump or blower to control the air pressure of the air bubble above the liquid in a largely airtight liquid tank. Depending on the design, creating overpressure or reducing underpressure can force liquid out of the tank and onto the pad through small openings in the lower part of the tank or through hoses originating there. The amount of liquid dispensed is generally dependent not only on the control of the air pump or blower, but also, among other things, on the liquid level in the tank.

[0005] Alternatively, it is known that robots with automated base or service stations can moisten their cleaning pads using a wet cleaning service function. The function that allows the cleaning pads to be cleaned or washed by the service station while still on the robot enables automated moistening of the pads "from the outside." Some robots no longer have an internal liquid tank; instead, they are moistened exclusively in the service station. To ensure even cleaning of larger floor areas, the robot returns to the service station after a predetermined interval, for example, every 5 to 15 minutes, depending on the settings, to have the cleaning pads cleaned and re-moistened.

[0006] The object of the invention is to provide a method for the automatic moistening of a cleaning pad, in which the device, during its cleaning cycle and with decreasing fill level of the cleaning fluid in the reservoir, adjusts the control of its air pump or air blower in such a way that a constant moistening of the cleaning pads over time can be achieved.

[0007] This problem is solved by a method for moistening a cleaning pad of a mobile, self-propelled device with the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

[0008] According to the invention, in a method for moistening a cleaning pad of a mobile, self-propelled device, which comprises a reservoir tank with cleaning fluid and tank outlets and an air pump or air blower for controlling an air pressure in the reservoir tank, the air pump or air blower is operated during a cleaning run of the device in such a way that, depending on a current fill level of the cleaning fluid, an air delivery rate of the air pump or air blower is regulated in such a way that volume flow changes from the tank outlets are compensated, wherein the current fill level of the cleaning fluid is estimated by the device on the basis of the previous control of the air pump or air blower.

[0009] This system utilizes the knowledge that, with the same pump control, the liquid level in the reservoir affects the flow rate from the nozzles, and that cleaning performance increases with the increasing amount of liquid applied to the cleaning pad. Specifically, during the cleaning cycle, the air supply is adjusted according to the physical effects that occur, in order to compensate for the change in volume flow from the tank outlets caused by the decreasing level of cleaning fluid in the reservoir. This allows the cleaning results to be advantageously maintained consistently throughout the entire cleaning cycle with the cleaning pad.Either the cleaning results at the beginning (or alternatively towards the end) of the cleaning cycle can be specifically improved by avoiding a reduced liquid output compared to the average, or the cleaning range increases by the lower liquid output towards the end (or alternatively at the beginning) of the cleaning cycle. At the same time, excessive wetting of the floor is prevented.

[0010] The following advantages are achieved as a result: The floor surfaces to be cleaned are cleaned evenly with a damp cloth; all areas are covered with the consistently moistened cleaning pad. This prevents the cleaning pad from becoming too wet, which improves the visual result by avoiding noticeable marks, increases the cleaning range, and reduces the risk of damaging a wooden floor. Likewise, insufficient moisture of the cleaning pad, which would lead to a poorer cleaning effect, is avoided. The estimation-based and, in particular, sensor-free implementation (i.e., without sensors to determine the fill level in the reservoir) results in low manufacturing costs, as no additional components need to be installed.

[0011] A mobile, self-driving device is understood to be, in particular, a floor cleaning device that autonomously cleans floor surfaces, especially in the home. This includes combination devices, such as vacuuming and mopping robots. These devices operate (during cleaning mode) preferably with little or no user intervention. For example, the device automatically moves to a room specified by the user to clean the floor according to a pre-programmed cleaning strategy.

[0012] The device is a cleaning robot that has at least one wet cleaning module and may additionally include a suction nozzle (possibly with a brush roller), a suction blower, and a side brush. A control unit is responsible for evaluating sensor data, planning cleaning missions, determining the routes to be traveled, and controlling the actuators. A drive system enables the device to move in a controlled manner.

[0013] The wet cleaning module includes a reservoir for cleaning fluid, which can be refilled manually by the user or automatically by a service station. An air pump or blower is used to pump air into the reservoir, allowing cleaning fluid to drip out and be directed to the cleaning pad. The wet cleaning module can also incorporate an actuator for moving (vibrating, oscillating, rotating) the cleaning pad(s).

[0014] During a cleaning cycle, the device moistens its cleaning pad at defined intervals to prevent the cleaning pad from drying out: After a set time, distance traveled, number of wheel revolutions or cleaned area, the device activates its air pump or air blower for a usually relatively short period and thus transports cleaning fluid to the cleaning pad.

[0015] Depending on the fill level of the reservoir tank, the control of the air pump or air blower is adjusted to ensure the cleaning pad remains as consistently moistened as possible throughout the entire cleaning process.

[0016] The air pump is preferably a diaphragm air pump, which, instead of pumping cleaning fluid from the reservoir onto the cleaning pad, pumps air into the reservoir. The cleaning fluid dripping from the reservoir outlets located below the reservoir—due to gravity and, if applicable, the overpressure generated by the pump—creates a vacuum in the reservoir after the diaphragm air pump stops, preventing further dripping after a short time. The air pumped into the reservoir by the diaphragm air pump eliminates the vacuum, and, if necessary, builds up overpressure, allowing more cleaning fluid to be applied to the cleaning pad.

[0017] It is important to note that air, compared to water-based cleaning fluid, can be compressed or expanded much more significantly. This leads to two main effects: As the pressure in the reservoir tank increases, the air delivery rate of the diaphragm air pump decreases. Conversely, with a higher fluid volume and lower air volume in the reservoir tank, the air delivery rate decreases more rapidly because the pressure in the tank increases more quickly. The less cleaning fluid there is in the reservoir tank, i.e., the more air it contains, the more cleaning fluid can drip from the reservoir after the diaphragm air pump stops, assuming the same initial pressure, before an equilibrium is re-established at the tank outlets due to the vacuum, inertia, and gravity of the fluid.

[0018] In an advantageous embodiment, changes in the volume flow from the tank outlets are compensated by adjusting the power output, operating time, and / or interval times of the air pump or blower. In particular, depending on the physical effects that occur, the air pump or blower is operated less frequently (or more frequently), with decreasing (or increasing) power, or for shorter (or longer) periods.

[0019] The reduction (or alternatively, increase) of the air volume per pump cycle is achieved in various ways: The air pump or air blower is operated at decreasing (or alternatively, increasing) power during a cleaning cycle. While the air pump or air blower pumps more (or alternatively, less) air into the reservoir during a humidification cycle when the reservoir is full, it operates at a higher (or alternatively, lower) power. As the cleaning fluid level decreases, the power of the air pump or air blower is continuously adjusted to pump less (or alternatively, more) air into the reservoir per humidification cycle.

[0020] The air pump or air blower operates during a cleaning cycle with decreasing (or alternatively increasing) operating time. When the reservoir is full, the air pump or air blower pumps more (or less) air into the reservoir for a longer (or alternatively shorter) time per humidification cycle. As the cleaning fluid level decreases, the activation time of the air pump or air blower is continuously adjusted to pump less (or more) air into the reservoir per humidification cycle.

[0021] The air pump or blower operates at increasingly longer (or shorter) intervals during a cleaning cycle. While the air pump or blower initiates a humidification cycle relatively quickly (or after a longer period) when the reservoir is full, pumping a defined amount of air into the reservoir, the interval between activations is progressively adjusted as the cleaning fluid level decreases. This results in less (or more) frequent air pumping into the reservoir. The higher (or lower) amount of cleaning fluid delivered to the cleaning pad, given a constant pumping time, is thus compensated for by the decreasing (or increasing) frequency of humidification.

[0022] Naturally, a combination of these variants also achieves the advantage of constant moistening of the cleaning pad throughout the entire cleaning cycle of the device.

[0023] In a further advantageous embodiment, the cleaning fluid output is kept constant during the cleaning cycle. The control of the air pump or air blower over time depends on the level of cleaning fluid in the reservoir or the volume of air in the tank. Depending on the reservoir level, the control of the air pump or air blower is adjusted to ensure the most consistent possible moistening of the cleaning pad throughout the entire cleaning cycle.

[0024] In a further advantageous embodiment, the consumption of the cleaning fluid as a function of the air pump or air blower control is determined by laboratory tests, for example, stored in lookup tables and made available to the device. With this data, it is possible to reliably estimate the current fill level in the reservoir or the consumption of the cleaning fluid, even without an additional sensor for detecting the fill level (i.e., sensor-free), and to adjust the control of the air pump or air blower accordingly.

[0025] In a further advantageous embodiment, at least one sensor detects a predetermined fill level, from which the current fill level of the cleaning fluid is estimated. The device therefore does not have a fill level sensor, but only one or more sensors for detecting specific fill levels (e.g., full reservoir, half-full tank, etc.) (e.g., electrical contacts). Based on this data, the device can estimate the consumption of the cleaning fluid based on the pump control: with each activation of the air pump or air blower, the level of the cleaning fluid decreases.

[0026] In another advantageous embodiment, the device has no sensors in the reservoir tank, but a sensor that detects whether the reservoir tank or the wet cleaning module is removed from the device and then reattached. When the reservoir tank is removed, it is assumed that a user has refilled it, and that it is completely full again after being reinserted. Preferably, the duration for which the wet cleaning module or reservoir tank was removed is compared to a threshold value. If the threshold value is not exceeded, it is assumed that the wet cleaning module or reservoir tank was not removed from the device long enough to refill with cleaning fluid. Based on the assumption that the reservoir tank is refilled, the device can estimate the consumption of the cleaning fluid and thus the current fill level of the tank based on the pump control.

[0027] Depending on the type of pump installed, the detection of an empty storage tank and, if necessary, the estimation of the fill level can also be achieved based on the electrical power consumption of the pump (and its curve).

[0028] In another advantageous embodiment, each time the device docks at a service station, the system infers that the reservoir tank is being refilled and, based on this, determines the current fill level of the cleaning fluid. Even without sensors in the reservoir tank, it is possible to assume that the reservoir tank is being refilled if the device's service station has a refilling function. Each time the device docks at its service station, the service station can transfer cleaning fluid from its fresh water tank or a fresh water connection into the device's reservoir tank.

[0029] In a further advantageous embodiment, the air delivery rate of the air pump or air blower and / or the estimation of the current fill level depend on a selected cleaning mode of the device. It is intended that the device should achieve different moisture levels of the cleaning pad in different cleaning modes (Eco, Power, etc.) and therefore must also apply different amounts of cleaning fluid to the cleaning pad. The method according to the invention is therefore designed for different quantities of cleaning fluid (or different power levels of the air pump or air blower).

[0030] In a further advantageous embodiment, a boost function is used at the beginning of the cleaning cycle and / or during intensive cleaning to pre-moisten the cleaning pad, with the air pump or air blower being controlled depending on the current fill level. If the cleaning pad is dry at the start of a cleaning cycle, it is pre-moistened using the boost function. Here, too, the pump is controlled depending on the liquid level in the reservoir. The same applies when the device uses a boost function for intensive cleaning of specific areas.

[0031] The invention further relates to a mobile, self-propelled device equipped to carry out a method as described. It is understood that, in addition to the method and the device, a computer program product comprising commands that, upon execution of the program, cause a device to perform the method according to the invention is also included in the scope of this invention. Likewise, a computer-readable medium on which such a computer program product is stored is included in the scope of this invention.

[0032] Any features, designs, embodiments and advantages relating to the method also apply in connection with the device according to the invention, computer program product and computer-readable medium, and vice versa.

[0033] The invention is explained in more detail with reference to the following examples. These examples show: Figures 1A, 1B: each a schematic view of an embodiment of a mobile, self-propelled device provided for the method according to the invention; Figure 2: a schematic view of an embodiment of a mobile, self-propelled device provided for the method according to the invention; Figures 3A, 3B: each a schematic view of an embodiment of a wet cleaning module provided for the method according to the invention; Figures 4A, 4B, 4C: each diagrams for controlling the air pump or air blower over time for a constant moistening of the cleaning pad; and Figure 5: a flowchart of an embodiment of a method according to the invention.

[0034] In Figure 1A is a mobile, self-driving device, in particular a robot 10 shown in overhead view. Figure 1B shows robot 10 of the Figure 1Ain a bottom view. The robot 10 includes a suction opening 1 in which a brush roller 2 is integrated. The robot 10 also has a side brush 3 with side brush arms at a front lateral position on its housing. The side brush 3 is designed to transport dust and dirt, especially along walls and in corners, to the suction opening 1 of the robot vacuum.

[0035] Robot 10 is also equipped with navigation sensors that can perceive its surroundings. For example, the robot has a LIDAR sensor 4 on its housing. A control system for Robot 10 can interpret the sensor data from the LIDAR sensor 4 to determine, among other things, which room, or what type of room, and its current location within that room. Robot 10 can infer the type of room from its furnishings and decor.

[0036] In addition to its dry cleaning unit (brush roller 2, possibly a suction blower, side brush 3), the robot 10 has a wet cleaning module (reservoir, pump, cleaning pad 5, possibly actuator for cleaning pad movement).

[0037] In Figure 2 Is the robot 10 of the Figure 1AThe simplified representation shows the robot 10. A controller 6 in the robot is responsible for evaluating the sensor data (including the LiDAR sensor 4), planning cleaning missions, planning the routes to be traveled, and controlling the actuators. A drive 7 enables the robot 10 to move in a controlled manner. The controller 6 also controls a diaphragm air pump 8 in the wet cleaning module. Furthermore, the robot 10 has a reservoir 9 containing cleaning fluid, which is used to moisten the cleaning pad 5. A diaphragm air pump 8 is used to pump air into the reservoir 9, causing cleaning fluid to drip out and onto the cleaning pad 5.

[0038] The functionality of the wet cleaning module is described in the Figure 3A , 3BAs shown, air is pumped into the reservoir 9 by the diaphragm air pump 8. The cleaning fluid dripping from the tank outlets located below the reservoir 9 – due to gravity and, if applicable, the overpressure generated by the pump 8 – creates a vacuum in the reservoir 9 after the pump 8 stops, which prevents further dripping after a short time. The air pumped into the reservoir 9 by the diaphragm air pump 8 eliminates the vacuum, builds up overpressure if necessary, and allows more cleaning fluid to be applied to the cleaning pad 5.

[0039] Compared to water-based cleaning fluids, air can expand and compress much more significantly. Since the air delivery rate of the diaphragm air pump 8 decreases with increasing pressure in the reservoir 9, a higher liquid volume, and thus a lower air volume, in the reservoir 9 ( Figure 3A) the air delivery rate decreases more quickly because the pressure in reservoir 9 increases more rapidly. The less cleaning fluid in reservoir 9 ( Figure 3B The more air there is in the reservoir 9, the more cleaning fluid can drip out of the reservoir 9 after the pump 8 stops, at the same outlet pressure, before an equilibrium of vacuum, inertia, and gravity of the fluid is re-established at the tank outlets. Therefore, with the same control of the diaphragm air pump 8, the flow rate from the tank outlet nozzles increases as the fluid level in the reservoir 9 decreases.

[0040] To ensure consistent moistening of the cleaning pads 5 and thus uniform wet cleaning over time as the cleaning cycle progresses – when more cleaning fluid has been consumed from the reservoir 9 and therefore more air is present in the reservoir 9 – the control of the diaphragm air pump 8 is varied. A reduction in the amount of air per pump cycle can be achieved in various ways. This is related to the Figures 4A to 4C As shown. An increase in air volume can also be achieved in reverse temporal sequence.

[0041] Figure 4A This shows a decrease in pump performance over time. The diaphragm air pump operates with decreasing performance during a cleaning cycle.

[0042] While the diaphragm air pump pumps more air into the reservoir at a higher power output during a humidification cycle when the reservoir is full, the power output of the diaphragm air pump is continuously adjusted as the cleaning fluid level decreases in order to pump less air into the reservoir per humidification cycle.

[0043] Figure 4B This shows the reduction in the operating time of the diaphragm air pump over time. The diaphragm air pump operates with decreasing duration during a cleaning cycle. While the diaphragm air pump pumps air into the reservoir for a longer period per humidification cycle when the reservoir is full, the activation duration of the diaphragm air pump is continuously adjusted as the cleaning fluid level decreases, thus pumping less air into the reservoir per humidification cycle.

[0044] Figure 4CThis illustrates the increasing interval times of the diaphragm air pump. During a cleaning cycle, the diaphragm air pump operates at increasingly longer intervals. While the diaphragm air pump initiates a humidification cycle relatively quickly when the reservoir is full, pumping a defined amount of air into the reservoir, the interval until the next activation of the diaphragm air pump is progressively adjusted as the cleaning fluid level decreases, thus reducing the frequency of air pumping into the reservoir. The increased amount of cleaning fluid delivered to the cleaning pad for a constant pumping duration is therefore compensated for by the decreasing frequency of humidification.

[0045] The control of the diaphragm air pump over time depends on the level of cleaning fluid in the reservoir or the volume of air in the reservoir. This is estimated by the device based on registered events, knowledge of the controlled consumption of cleaning fluid, and the initial state. The basic sequence of the process with different initial conditions depending on the robot's configuration is described in Figure 5 depicted.

[0046] If the robot has sensors for measuring the fill level in the reservoir (not part of the invention), this level is detected (step 101a). Based on the current fill level, the robot activates its diaphragm air pump (step 104). The robot's cleaning pad is moistened with cleaning fluid (step 105).

[0047] If the robot does not have a level sensor, but only one or more sensors for detecting specific fill levels (e.g., full reservoir, half-full reservoir, etc.), then the robot detects the specific fill level in the reservoir using sensors (step 101b). Based on this data, the robot estimates the consumption of the cleaning fluid by controlling the pump: with each activation of the diaphragm air pump, the level of the cleaning fluid decreases (step 102a). Based on the current fill level estimate, the robot activates its diaphragm air pump (step 104). The robot's cleaning pad is moistened with cleaning fluid (step 105).

[0048] If the robot has no sensors in the reservoir, but does have a sensor that detects whether the wet cleaning module or reservoir is removed from and reattached to the robot (step 101c), the robot checks whether the removal time exceeds a predetermined threshold. If the threshold is not exceeded, it is assumed that the wet cleaning module or reservoir was not removed from the robot long enough to refill the cleaning fluid. The reservoir level is then assumed to remain unchanged (step 102c). If the removal time exceeds the threshold, the reservoir is assumed to be refilled (step 102b). In both cases, the robot estimates the cleaning fluid consumption based on the pump control (step 103a). Based on the current estimated fill level, the robot activates its diaphragm air pump (step 104).The robot's cleaning pad is moistened with cleaning fluid (step 105).

[0049] If the robot has no sensors but a service station with refill functionality, it is assumed that the reservoir will be refilled when the robot docks at this service station (step 101d). If the reservoir is refilled at the service station, the robot assumes it is full when it undocks (step 102d). If, however, the service station does not refill the reservoir, the reservoir level remains unchanged (step 102e). In both cases, the robot estimates the cleaning fluid consumption based on the pump control (step 103b). Based on the current estimated level, the robot activates its diaphragm air pump (step 104). The robot's cleaning pad is moistened with cleaning fluid (step 105).

Claims

1. Method for moistening a cleaning pad (5) of a mobile, self-propelled device comprising a storage tank (9) containing cleaning fluid and tank outlets and an air pump or air blower, wherein the air pump or air blower is operated during a cleaning run of the device in such a way that, depending on the current fill level of the cleaning fluid, an air delivery rate of the air pump or air blower is regulated in such a way as to compensate for volume flow changes from the tank outlets, wherein the current fill level of the cleaning fluid is estimated by the device on the basis of the control of the air pump or air blower.

2. Method according to claim 1, wherein the volume flow changes from the tank outlets are compensated by adjusting - the power of the air pump or air blower, - the operating time of the air pump or air blower, and / or - the interval times of the air pump or air blower.

3. Method according to one of the preceding claims, wherein the cleaning fluid output is kept constant during the cleaning cycle with an unchanged cleaning mode.

4. Method according to one of the preceding claims, wherein a quantity of cleaning fluid consumption is determined by laboratory tests as a function of the control of the air pump or air blower and is made available to the device.

5. Method according to one of the preceding claims, wherein a predetermined fill level is detected with at least one sensor, from which the current fill level of the cleaning fluid is estimated.

6. Method according to one of the preceding claims, wherein at least one sensor detects the removal and / or attachment of the storage tank (9), and, starting from a removed storage tank (9), infers over a predetermined period of time whether the storage tank (9) has been refilled and, based thereon, the current fill level of the cleaning fluid.

7. Method according to one of the preceding claims, wherein, each time the device docks at a service station, a refill of the storage tank (9) is inferred and, based thereon, the current fill level of the cleaning fluid is determined.

8. Method according to one of the preceding claims, wherein the air delivery rate of the air pump or air blower and / or the estimation of the current fill level depend on a set cleaning mode of the device.

9. Method according to one of the preceding claims, wherein at the beginning of the cleaning cycle and / or during intensive cleaning a boost function is used to pre-moisten the cleaning pad (5), in which the control of the air pump or air blower is carried out depending on the current fill level.

10. Mobile, self-driving device configured to perform a method according to any of the preceding claims.

11. Computer program product comprising instructions which, when the program is executed by the device, cause it to execute the method according to any one of the preceding claims 1 to 9.

12. Computer-readable data carrier on which the computer program product according to claim 11 is stored.

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