Method for moistening a cleaning pad

Abstract

A method is specified for moistening a cleaning pad (5) of a mobile, self-propelled device, which comprises a storage tank (9) with cleaning fluid and tank outlets and an air pump or an air blower, in which the air pump or the 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 the air blower is regulated in such a way that changes in the volume flow from the tank outlets are compensated, the current fill level of the cleaning fluid being estimated by the device on the basis of the control of the air pump or the air blower.

Description

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

[0002] Floor cleaning robots are designed to relieve their users of repetitive tasks such as sweeping, vacuuming, or mopping, or make them easier. In addition to regular cleaning, users particularly value a visually clean cleaning result. After the robot has completed its cleaning cycle, there should be no dust or stains visible on the floors. Combination vacuum and mop devices that combine dry cleaning (sweeping and vacuuming) with 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 cleaning robot repeatedly pumps water or cleaning fluid from its storage tank onto the cleaning pads (usually at certain 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 reducing the hygienic aspects of the cleaning, can also lead to an optical impairment of the results.

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

[0004] Another way to control the liquid release in a largely airtight liquid tank is to use an air pump or air blower to control the air pressure of the air bubble above the liquid. Depending on the design, this can be used to build up excess pressure or reduce negative pressure, thereby pumping liquid from the tank to the pad through small openings in the lower area of ​​the tank or hoses originating there. The amount of liquid released generally depends not only on the control of the air pump or air blower, but also, among other things, on the liquid level in the tank.

[0005] Alternatively, robots with automated base or service stations can be equipped with a wet cleaning service function to moisten the cleaning pads. This function, which allows the service station to clean or rinse the cleaning pads on the robot, makes it possible to automatically moisten the cleaning pads "from the outside" via the service station. Robots are known to do this without a built-in fluid tank, but are instead moistened exclusively in the service station. To ensure evenly cleaning larger floor areas, the robot returns to the service station after a predetermined period of time, for example, every 5 to 15 minutes, depending on the settings, to clean and re-moisten the cleaning pads.

[0006] From DE 10 2020 212 050 A1, for example, a cleaning nozzle is known in which air is pumped into the interior of a liquid container using an air pump in order to increase the internal pressure.

[0007] For example, CN 2 17 659 598 U discloses a cleaning robot with wiping pads and a liquid container for cleaning fluid.

[0008] The object of the invention is to provide a method for automatically moistening a cleaning pad, in which the device adapts the control of its air pump or air blower during its cleaning run and as the level of the cleaning fluid in the storage tank decreases in such a way that a constant moistening of the cleaning pads can be achieved over time.

[0009] This object is achieved by a method for moistening a cleaning pad of a mobile, self-propelled device having the features of claim 1. Advantageous embodiments and further developments are the subject of the subclaims.

[0010] According to the invention, in a method for moistening a cleaning pad of a mobile, self-propelled device, which comprises a storage tank with cleaning fluid and tank outlets and an air pump or an air blower for controlling an air pressure in the storage tank, the air pump or the 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 the 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 the air blower.

[0011] This application leverages the knowledge that the fluid level in the storage tank influences the flow rate from the nozzles, even with the same pump control, and that cleaning performance increases with the increasing amount of fluid applied to the cleaning pad. In particular, the air supply is adjusted during the cleaning run depending on the physical effects occurring in order to compensate for the change in volume flow from the tank outlets caused by the decreased level of cleaning fluid in the storage tank. This advantageously allows the cleaning results to be kept constant throughout the entire cleaning run with the cleaning pad.Either the cleaning results at the beginning (alternatively towards the end) of the cleaning run can be specifically improved by avoiding a lower liquid output than average, or the cleaning range can be increased by the lower liquid output towards the end (alternatively at the beginning) of the cleaning run. At the same time, excessive wetting of the floor is prevented.

[0012] The following advantages are achieved: - the floor surfaces to be cleaned are cleaned evenly with a damp cloth, all areas are covered with the evenly moistened cleaning pad; - it prevents the cleaning pad from being too wet, which improves the visual result by avoiding obvious marks, increases the cleaning range and reduces the risk of damaging a wooden floor; - It also avoids insufficient moisture in the cleaning pad, which would lead to a poorer cleaning effect; - the estimation-based and especially sensor-free implementation (i.e. without sensors to determine the fill level in the storage tank) leads to low manufacturing costs, since no additional components have to be installed.

[0013] A mobile, self-propelled device is specifically defined as a floor cleaning device that autonomously cleans floors, particularly in the home. This includes, among other things, combination devices, such as vacuum and floor-mopping robots. These devices preferably operate without, or with as little as possible, user intervention during operation (cleaning mode). For example, the device automatically drives into a room specified by the user to clean the floor according to a predefined and programmed process strategy.

[0014] The device is a cleaning robot that has at least one wet cleaning module and can also include a suction nozzle (possibly with a brush roller), a suction fan, and a side brush. A controller is responsible for evaluating the sensors, planning a cleaning mission, planning the routes to be traveled, and controlling the actuators. A drive enables the device to move in a targeted manner.

[0015] The wet cleaning module includes a storage tank for cleaning fluid, which can be refilled manually by the user or automatically by a service station. An air pump or air blower is used to pump air into the storage tank, allowing cleaning fluid to drip out of the tank and be directed to the cleaning pad. Additionally, the wet cleaning module can incorporate actuators to move (vibrate, oscillate, or rotate) the cleaning pad(s).

[0016] During a cleaning run, the device moistens its cleaning pad at defined intervals to prevent the cleaning pad from drying out: Always after a set period of time, distance traveled, wheel revolutions or cleaned area, the device activates its air pump or air blower for a usually relatively short period of time and in this way transports cleaning fluid to the cleaning pad.

[0017] Depending on the fill level of the storage tank, the control of the air pump or air blower is adjusted to ensure that the cleaning pad is moistened as consistently as possible throughout the entire cleaning cycle.

[0018] The air pump is preferably a diaphragm air pump, which instead of pumping the cleaning fluid from the storage tank onto the cleaning pad, pumps air into the storage tank. The cleaning fluid dripping from the tank outlets located below the storage tank—due to gravity and possibly the overpressure generated by the pump—creates a vacuum in the storage tank after the diaphragm air pump stops, which stops further dripping after a short time. The air pumped into the storage tank by the diaphragm air pump relieves the vacuum, builds up overpressure if necessary, and allows more cleaning fluid to be applied to the cleaning pad.

[0019] It should be noted that air can be compressed and expanded much more significantly than water-based cleaning fluid. This essentially leads to two effects: As the pressure in the storage tank increases, the air flow rate of the diaphragm air pump decreases. As the liquid volume and air volume in the storage tank increase, the air flow rate decreases more quickly because the pressure in the tank increases more quickly. The less cleaning fluid there is in the storage tank, i.e. the more air there is in the storage tank, the more cleaning fluid can drip out of the storage tank after the diaphragm air pump stops, assuming the same initial pressure in the storage tank, before an equilibrium between negative pressure, inertia, and the gravity of the fluid is once again established at the tank outlets.

[0020] In an advantageous embodiment, 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. In particular, depending on the physical effects occurring, the air pump or air blower is operated less frequently (or more frequently), with decreasing (or increasing) power, or for shorter (or longer) periods.

[0021] The reduction (alternatively increase) of the air volume per pump cycle is therefore possible in various ways: The air pump or air blower operates at decreasing (or increasing) power during a cleaning cycle. While the air pump or air blower operates at a higher (or lower) power when the storage tank is full, pumping more (or less) air into the storage tank during a humidification cycle, the air pump or air blower's power is continuously adjusted as the cleaning fluid level decreases, pumping less (or more) air into the tank per humidification cycle.

[0022] The air pump or air blower operates with a decreasing (or increasing) operating time during a cleaning cycle. While the air pump or air blower pumps more (or less) air into the storage tank for a longer (or shorter) time per humidification cycle when the storage tank is full, the duration of the air pump or air blower's activation is continuously adjusted as the cleaning fluid level decreases, pumping less (or more) air into the storage tank per humidification cycle.

[0023] The air pump or air blower is operated at increasingly longer (or shorter) intervals during a cleaning cycle. While the air pump or air blower starts a humidification cycle after a relatively short (or long) time when the storage tank is full, pumping a defined amount of air into the storage tank, the interval time until the air pump or air blower is next activated is continuously adjusted as the cleaning fluid level decreases, so that air is pumped into the storage tank less frequently (or more frequently). The higher (or lower) amount of cleaning fluid directed onto the cleaning pad with a constant pumping time is thus compensated for by the decreasing (or increasing) frequency of humidification.

[0024] Of course, a combination of these variants also achieves the advantage of constant moistening of the cleaning pad throughout the entire cleaning cycle of the device.

[0025] In a further advantageous embodiment, the cleaning fluid output is kept constant throughout the cleaning cycle. The control of the air pump or air blower over time depends on the level of cleaning fluid in the storage tank or the volume of air in the tank. Depending on the fill level of the storage tank, the control of the air pump or air blower is adjusted to ensure the most consistent moistening of the cleaning pad possible throughout the entire cleaning cycle.

[0026] In a further advantageous embodiment, the amount of cleaning fluid consumed is determined through laboratory tests depending on the control of the air pump or air blower, for example, stored in look-up tables and made available to the device. This data makes it possible to reliably estimate the current fill level in the storage tank or the cleaning fluid consumption, 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 based on this.

[0027] 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 storage tank, half-filled tank, etc.) (e.g., electrical contacts). Based on this data, the device can estimate the cleaning fluid consumption based on the pump control: with each activation of the air pump or air blower, the cleaning fluid level decreases.

[0028] In a further advantageous embodiment, the device does not have any sensors in the storage tank, but does have a sensor that detects whether the storage tank or the wet cleaning module is removed from the device and then reattached to it. If it is removed, it is assumed that a user has refilled the storage tank and that the storage tank is completely full again after it is inserted. Preferably, the time for which the wet cleaning module or storage tank is removed is compared with a threshold value. If the threshold value is not exceeded, it is assumed that the wet cleaning module or storage tank was not removed from the device long enough to refill the cleaning fluid. Assuming a refilled storage tank, the device can estimate the consumption of the cleaning fluid and thus the current fill level of the tank based on the pump control.

[0029] 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).

[0030] In a further advantageous embodiment, each time the device is docked at a service station, a conclusion is drawn as to whether the storage tank has been refilled, and the current cleaning fluid level is determined based on this. Even without sensors in the storage tank, it is possible to assume that the storage tank has been refilled if the device's service station has a refill function. Each time the device is docked at its service station, this can direct cleaning fluid from its fresh water tank or from a fresh water connection into the device's storage tank.

[0031] In a further advantageous embodiment, the air flow 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. The device is intended to achieve different levels of moisture on the cleaning pad in different cleaning modes (Eco, Power, etc.) and therefore also needs to apply different amounts of cleaning fluid to the cleaning pad. The method according to the invention is therefore designed for different amounts of cleaning fluid (or different power levels of the air pump or air blower).

[0032] In another 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. The air pump or air blower is controlled depending on the current fill level. If the cleaning pad is dry at the beginning of a cleaning cycle, the cleaning pad is pre-moistened using a boost function. Here, too, the pump is controlled depending on the fluid level in the storage tank. The same applies if the device uses a boost function for intensive cleaning of certain areas.

[0033] The invention further relates to a mobile, self-propelled device configured to perform a method as described. It is understood that, in addition to the method and the device, a computer program product comprising instructions that, when executed, cause a device to execute the method according to the invention is also within the scope of this invention. A computer-readable medium on which such a computer program product is stored is also within the scope of this invention.

[0034] Any features, configurations, embodiments and advantages relating to the method also apply in connection with the device, computer program product and computer-readable medium according to the invention, and vice versa.

[0035] The invention is explained in more detail with reference to the following embodiments, which are merely examples. They show: Fig. 1A, Fig. 1B: each shows a schematic view of an embodiment of a mobile, self-propelled device intended for the method according to the invention, Fig. 2: a schematic view of an embodiment of a mobile, self-propelled device intended for the method according to the invention, Fig. 3A, Fig. 3B: each a schematic view of an embodiment of a wet cleaning module provided for the method according to the invention, Fig. 4A, Fig. 4B, Fig. 4C: diagrams for controlling the air pump or the air blower over time for a constant moistening of the cleaning pad, and Fig. 5: a flowchart of an embodiment of a method according to the invention.

[0036] In Fig. 1A is a mobile, self-propelled device, in particular a robot 10 shown in plan view. Fig. 1B shows the robot 10 of the Fig. 1A in a bottom view. The robot 10 comprises a suction inlet 1 into which a brush roller 2 is integrated. Furthermore, the robot 10 has a side brush 3 with side brush arms at a front lateral position of its housing. The side brush 3 is designed to transport dust and dirt, particularly from walls and corners, to the suction inlet 1 of the vacuum robot.

[0037] The robot 10 also has navigation sensors that can detect the surroundings of the robot 10. For example, the robot has a LIDAR sensor 4 on the housing of the robot 10. A controller of the robot 10 can, among other things, use the sensor data from the LIDAR sensor 4 to interpret which room or type of room the robot 10 is currently in and where within this room it is located. The robot 10 can infer the type of room from the furnishings and furniture.

[0038] In addition to its dry cleaning unit (brush roller 2, possibly a suction fan, side brush 3), the robot 10 has a wet cleaning module (storage tank, pump, cleaning pad 5, possibly actuators for cleaning pad movement).

[0039] In Fig. 2 is the robot 10 of the Fig. 1A in a simplified representation. In the robot 10, a controller 6 is responsible for evaluating the sensors (including the LiDAR sensor 4), planning a cleaning mission, planning the routes to be traveled, and controlling the actuators. A drive 7 enables the robot 10 to move in a targeted manner. The controller 6 also controls a diaphragm air pump 8 in the wet cleaning module. The robot 10 also has a storage tank 9 with cleaning fluid, which is intended to moisten the cleaning pad 5. A diaphragm air pump 8 is used to pump air into the storage tank 9 so that cleaning fluid drips out of the storage tank 9 and is guided to the cleaning pad 5.

[0040] The functionality of the wet cleaning module is described in the Fig. 3A, Fig. 3B. The diaphragm air pump 8 pumps air into the storage tank 9. The cleaning fluid dripping out of the tank outlets located below the storage tank 9—due to gravity and, if applicable, the overpressure generated by the pump 8—creates a negative pressure in the storage tank 9 after the pump 8 stops, which stops further dripping after a short time. The air pumped into the storage tank 9 by the diaphragm air pump 8 relieves the negative pressure, builds up an overpressure if necessary, and allows additional cleaning fluid to be applied to the cleaning pad 5.

[0041] Compared to water-based cleaning fluids, air can be expanded and compressed very significantly. Since the air flow rate of the diaphragm air pump 8 decreases with increasing pressure in the storage tank 9, the air flow rate decreases with increasing fluid volume and thus lower air volume in the storage tank 9 ( Fig. 3A) the air flow rate decreases more quickly because the pressure in the storage tank 9 increases more quickly. The less cleaning fluid in the storage tank 9 ( Fig. 3B), i.e., the more air there is in the storage tank 9, the more cleaning fluid can drip from the storage tank 9 after the pump 8 stops, at the same outlet pressure in the storage tank 9, before an equilibrium of negative pressure, inertia, and gravity of the fluid is again established at the tank outlets. As a result, the outflow rate from the tank outlet nozzles increases with decreasing fluid level in the storage tank 9, assuming the same control of the diaphragm air pump 8.

[0042] In order to ensure consistent moistening of the cleaning pads 5 and thus uniform wet cleaning as the cleaning cycle progresses - when more cleaning fluid has been consumed from the storage tank 9 and therefore more air is present in the storage tank 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 in connection with the Fig. 4A to 4C. An increase in air volume can also be achieved in the reverse time sequence.

[0043] Fig. Figure 4A shows a decrease in pump performance over time. The diaphragm air pump operates at a decreasing performance during a cleaning run.

[0044] While the diaphragm air pump pumps more air into the storage tank at a higher power level during a humidification cycle when the storage tank is full, the performance of the diaphragm air pump is continuously adjusted as the cleaning fluid level decreases in order to pump less air into the storage tank per humidification cycle.

[0045] Fig. Figure 4B shows the reduction in the operating time of the diaphragm air pump over time. The diaphragm air pump operates for a decreasing amount of time during a cleaning cycle. While the diaphragm air pump pumps air into the storage tank for a longer period of time per humidification cycle when the storage tank is full, the duration of the diaphragm air pump's activation is continuously adjusted as the cleaning fluid level decreases, thus pumping less air into the storage tank per humidification cycle.

[0046] Fig. Figure 4C shows the extension of the diaphragm air pump's interval times. The diaphragm air pump is operated at increasingly longer intervals during a cleaning run. While the diaphragm air pump starts a humidification cycle after a relatively short time when the storage tank is full, pumping a defined amount of air into the storage tank. As the cleaning fluid level decreases, the interval time until the diaphragm air pump is next activated is continuously adjusted, thus pumping air into the storage tank less frequently. The increased amount of cleaning fluid delivered to the cleaning pad, given a constant pumping time, is thus offset by the decreasing frequency of humidification.

[0047] The control of the diaphragm air pump over time depends on the level of the cleaning fluid in the storage tank or the volume of air in the storage tank. This is estimated by the device based on recorded events, knowledge of the controlled consumption of the cleaning fluid, and the initial state. The basic procedure with different initial situations depending on the robot's equipment is described in Fig. 5 shown.

[0048] If the robot has sensors for measuring the fill level in the storage tank (not part of the invention), this is detected by sensors (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).

[0049] If the robot does not have a fill level sensor, but only one or more sensors for detecting specific fill levels (e.g., full storage tank, half-filled storage tank, etc.), the robot detects the specific fill level in the storage tank using sensors (step 101b). Based on this data, the robot estimates the cleaning fluid consumption based on the pump control: with each activation of the diaphragm air pump, the cleaning fluid level 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).

[0050] If the robot does not have any sensors in the storage tank, but does have a sensor that detects whether the wet cleaning module or storage tank is removed from the robot and then reattached to it (step 101c), the robot checks whether the withdrawal time exceeds a predetermined threshold. If the threshold is not exceeded, it is assumed that the wet cleaning module or storage tank was not removed from the robot long enough to refill the cleaning fluid. The storage tank fill level is assumed to be unchanged (step 102c). If the withdrawal time exceeds the threshold, it is assumed that the storage tank is refilled (step 102b). In both cases, the robot estimates the cleaning fluid consumption based on the pump control (step 103a). 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).

[0051] If the robot has no sensors but a service station with refill functionality, it is assumed that the storage tank has been refilled when the robot docks at this service station (step 101d). If the storage tank is refilled at the service station, the robot assumes a full level upon undocking (step 102d). If, however, the service station does not refill the storage tank, the fill level in the storage tank 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 fill level estimate, 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, which comprises a storage tank (9) with cleaning fluid and tank outlets and an air pump or an air blower, in which the air pump or the 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 flow rate of the air pump or the air blower is regulated in such a way that changes in the volume flow 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 the air blower. [2] Method according to claim 1, wherein the volume flow changes from the tank outlets are compensated by - a power of the air pump or air blower, - an operating time of the air pump or air blower, and / or - Interval times of the air pump or air blower can be adjusted. [3] Method according to one of the preceding claims, wherein a cleaning fluid discharge is kept constant during the cleaning run with an unchanged cleaning mode. [4] Method according to one of the preceding claims, wherein an amount of consumption of the cleaning fluid is determined by laboratory tests as a function of the control of the air pump or the air blower and is made available to the device. [5] Method according to one of the preceding claims, wherein at least one sensor detects a predetermined fill level, 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 a removal and / or attachment of the storage tank (9), and, starting from a removed storage tank (9) over a predetermined period of time, a conclusion is drawn as to a refilling of the storage tank (9) and, based thereon, on the current fill level of the cleaning fluid. [7] Method according to one of the preceding claims, wherein each time the device is docked at a service station, a refilling of the storage tank (9) is determined 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 flow rate of the air pump or the air blower and / or the estimation of the current fill level are dependent on a set cleaning mode of the device. [9] Method according to one of the preceding claims, wherein at the beginning of the cleaning run 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 the air blower takes place depending on the current fill level. [10] Mobile, self-propelled device adapted to carry out a method according to any one of the preceding claims. [11] A computer program product comprising instructions which, when the program is executed by the device, cause the device to carry out the method according to any one of the preceding claims 1 to 9. [12] A computer-readable data carrier on which the computer program product according to claim 11 is stored.

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