Method for operating a floor cleaning machine

Abstract

A method for operating a floor cleaning machine, wherein the floor cleaning machine has a cleaning liquid container, a dirty liquid container and a running gear for moving the floor cleaning machine over a floor surface to be cleaned, wherein the floor cleaning machine has a cleaning device with cleaning elements designed to engage with the floor surface to be cleaned, wherein the method comprises the following steps: moving the floor cleaning machine over the floor surface to be cleaned, detecting the amount of cleaning liquid supplied from the cleaning liquid tank to the cleaning device within a first time interval during the movement, detecting the amount of dirty liquid discharged from the dirty liquid collecting device to the dirty liquid container within a second time interval during the movement, comparing the detected amount of cleaning liquid with a first threshold value, comparing the detected amount of dirty liquid with a second threshold value, outputting a first error signal if the detected amount of cleaning liquid is greater than the first threshold value and the detected amount of dirty liquid is less than the second threshold value.

Description

Technical Field

[0001] This invention relates to a method for operating a floor cleaning machine, wherein the floor cleaning machine includes a cleaning fluid container, a waste fluid container, and a walking mechanism for moving the floor cleaning machine on a surface to be cleaned. Furthermore, the floor cleaning machine has a cleaning device with cleaning elements and a waste fluid collection device. The cleaning device is designed to engage with the surface to be cleaned, and the waste fluid collection device is connected to the waste fluid container to discharge waste fluid from the collection device to the container. The waste fluid collection device is also designed to collect waste fluid from the surface to be cleaned. The invention further relates to a floor cleaning machine designed to carry out this method. Background Technology

[0002] Such floor cleaning machines are known from the prior art. During operation, cleaning fluid (e.g., clean water) from a cleaning fluid container is applied to the surface to be cleaned via a cleaning device, wherein the cleaning element engages with the surface to remove dirt in conjunction with the cleaning fluid. Using a waste collection device (which may be designed, for example, a suction nozzle), the previously applied cleaning fluid, after engaging with the surface, carries away dirt and becomes waste liquid, which is then collected again and sent to a waste liquid container.

[0003] These so-called washer-dryers can be implemented as handheld or ride-on machines. They can also be implemented as so-called autonomous cleaning robots, eliminating the need for direct operator monitoring.

[0004] However, the following problems may arise when operating such a machine.

[0005] When cleaning fluid is applied to a surface to be cleaned, but the waste collection device malfunctions, cleaning fluid carrying dirt (i.e., waste liquid) will remain on the surface. This poses a safety hazard, as it increases the risk of slipping on the surface. Furthermore, it fails to achieve the desired cleaning effect.

[0006] Furthermore, such floor cleaners typically include a suction unit (such as a suction turbine) driven by an electric motor. This creates an airflow from a waste collection device (which may be designed as a suction nozzle) toward a waste container, whereby the airflow carries away and transports the waste from the collection device into the waste container. If the motor current of the electric motor decreases while the voltage remains constant, there are usually two possible reasons. First, it is possible that the connection between the waste collection device and the waste container is blocked, preventing more airflow from the waste collection device into the waste container. This results in less air being delivered by the suction unit, thus reducing the motor current. This leads to a malfunction.

[0007] However, another scenario is that the wastewater collection device may contain such a large amount of liquid that it prevents ambient air from entering the device, thus hindering airflow. This is not a malfunction, but rather a situation that ends when the liquid in the collection device is drawn into the wastewater container due to negative pressure. However, these two scenarios cannot be distinguished solely from motor current measurements. In particular, it is impossible to determine the presence of a malfunction based on this alone. Summary of the Invention

[0008] Therefore, based on the prior art, the purpose of this invention is to provide a method for operating a floor cleaning machine and a machine that can reliably identify faults during operation.

[0009] According to a first aspect of the invention, this object is achieved by a method for operating a floor cleaning machine, wherein the floor cleaning machine has a cleaning liquid container, a waste liquid container, and a walking mechanism for moving the floor cleaning machine on a surface to be cleaned, wherein the floor cleaning machine has a cleaning device with cleaning elements designed to engage with the surface to be cleaned, wherein the cleaning device is connected to the cleaning liquid container for supplying cleaning liquid to the cleaning device, and the cleaning device is designed to apply the cleaning liquid to the surface to be cleaned, wherein the floor cleaning machine has a waste liquid collection device connected to the waste liquid container for discharging waste liquid from the waste liquid collection device to the waste liquid container, and the waste liquid collection device is designed to collect waste liquid from the surface to be cleaned, wherein the method comprises the following steps:

[0010] - To move the floor cleaning machine on the surface to be cleaned.

[0011] - During the operation, the amount of cleaning fluid supplied from the cleaning fluid tank to the cleaning device is detected within the first time interval.

[0012] - During the operation, the amount of wastewater discharged from the wastewater collection device to the wastewater tank is detected during the second time interval.

[0013] - Compare the detected amount of cleaning fluid with a first threshold.

[0014] - Compare the amount of detected contaminant with a second threshold.

[0015] - If the amount of detected cleaning fluid is greater than the first threshold and the amount of detected contaminant is less than the second threshold, then output the first error signal.

[0016] In the method according to the invention, during operation (i.e., while the machine is moving on the surface to be cleaned), it is detected whether cleaning fluid has been applied to the surface using a cleaning device. This is accomplished by detecting the amount of cleaning fluid applied within a first time interval using a suitably designed device and comparing it to a threshold. The threshold can be chosen to be very low or zero. However, by comparing it with a non-zero threshold, it is ensured that a lower measurement by the device does not automatically result in the cleaning fluid actually being applied to the surface by the cleaning device.

[0017] In addition, another device detects the amount of sewage discharged from the sewage collection device and sent into the sewage container during the second time interval.

[0018] Here, the first time interval and the second time interval can overlap, that is, the detection can be carried out simultaneously, or the second time interval is after the first time interval in time, so as to take into account that the cleaning liquid applied to the ground surface to be cleaned can be collected again by the waste liquid collection device after a certain period of time.

[0019] The amount of collected contaminated liquid detected is compared with a second threshold, which can be chosen to be very low or even zero. However, this threshold comparison also ensures that the previously described artifacts do not occur.

[0020] Finally, in the method according to the invention, if, on the one hand, the amount of discharged cleaning fluid detected during a first time interval is higher than a threshold and the amount of discharged waste fluid detected during a second time interval is lower than a threshold, an error signal is output. Therefore, it can be detected that the waste fluid collection device has failed to operate reliably.

[0021] This is either based on displaying an error signal to the user, or using the error signal to shut down any possible drive unit of the floor cleaner that drives the walking mechanism and moves the floor cleaner over the surface to be cleaned.

[0022] The method according to the invention is particularly advantageous when used with autonomous floor cleaning machines, because in this case the user cannot directly detect any residual waste on the surface to be cleaned, and the user can then actively stop the cleaning operation. Compared to the prior art, malfunctions in the waste collection device are reliably and automatically identified during operation.

[0023] In a preferred embodiment, the floor cleaning machine has a pumping device that applies negative pressure to the waste tank and has an electrically driven motor that is supplied with a voltage of a predetermined intensity during operation, thereby causing a power supply current to flow through the motor. The intensity of the power supply current is detected within a third time interval. The detected power supply current intensity is compared with a third threshold. The detected amount of waste is compared with a fourth threshold. If the detected power supply current intensity is less than the third threshold and the detected amount of waste is less than the fourth threshold, a second error signal is output.

[0024] In this preferred embodiment of the method according to the invention, in addition to detecting the motor current of the pumping device, it is also possible to detect whether sewage is being fed into the sewage container. A second error signal is only output if this is not the case, because a malfunction has clearly occurred, caused by a blockage in the pipeline between the sewage collection device and the sewage container.

[0025] However, if the sewage is still being pumped into the sewage container when the motor current is too low, the conditions for the second error signal are not met, because there is obviously no malfunction, but rather the sewage itself is causing the pumping device to pump only a small amount of air or none at all, which also leads to the reduction of the motor current.

[0026] Therefore, in this preferred embodiment, the fault is not only detected by using the motor current of the pumping device, but also by combining it with the detection of the amount of sewage delivered to the sewage container.

[0027] It should be noted that this is a unique concept of the present invention, namely, that the motor current of the pumping device and the amount of sewage fed into the sewage container are detected within a time interval, and then an error signal is output if both the amount of sewage delivered and the motor current are lower than a predetermined threshold.

[0028] The floor cleaning machine may in particular have a device designed to detect the amount of cleaning fluid supplied from the cleaning fluid tank to the cleaning device during a first time interval, and a device designed to detect the amount of wastewater discharged from the wastewater collection device to the wastewater tank during a second time interval. Furthermore, it is preferable to also include a device designed to detect the intensity of the supply current during a third time interval.

[0029] In a further preferred embodiment, the cleaning fluid container and the cleaning device are connected via a cleaning fluid pipeline for supplying the cleaning fluid, wherein a flow sensor is installed in the cleaning fluid pipeline as a device for detecting the amount of cleaning fluid supplied within a first time interval. Using a flow sensor in the pipeline is a reliable method for detecting the amount of problematic cleaning fluid.

[0030] As a replacement for or supplement to the flow sensor, a cleaning fluid pump can be installed in the cleaning fluid line. This pump is designed to detect the amount of cleaning fluid supplied to the cleaning device within a first time interval, thus functioning as a device for detecting the amount of cleaning fluid supplied from the cleaning fluid tank to the cleaning device within the first time interval. In this case, no other sensors are needed besides the pump. Adding another sensor provides system redundancy, ensuring the system continues to operate even if one of the two devices used for flow detection fails.

[0031] In a further preferred embodiment, a first device is provided for detecting the liquid level in the cleaning fluid container. This first device detects changes in the liquid level within the cleaning fluid container over a first time interval, thereby detecting the amount of cleaning fluid supplied during the first time interval. In this case, the amount of cleaning fluid supplied to the cleaning device is determined by the change in the liquid level in the cleaning fluid container. This is readily achievable in terms of equipment technology. Specifically, this can be achieved by having the first device for detecting the liquid level in the cleaning fluid container have a float, wherein changes in the position of the float are detected over the first time interval, thereby detecting the amount of cleaning fluid supplied during the first time interval.

[0032] Furthermore, it is preferable to include a second device for detecting the liquid level in the wastewater container, wherein the second device detects changes in the liquid level in the wastewater container during a second time interval, thereby detecting the amount of cleaning fluid supplied during the first time interval. Therefore, in this preferred embodiment, the amount of wastewater discharged into the wastewater container is also determined based on changes in its liquid level. In this case, it is particularly preferable that the second device for detecting the liquid level in the wastewater container is designed as a pressure sensor.

[0033] Finally, in another aspect of the invention, the above-mentioned objective is achieved by a floor cleaning machine designed to perform the method according to the invention. Attached Figure Description

[0034] In the following description, the invention will be illustrated with reference to figures showing only preferred embodiments, wherein...

[0035] Figure 1 A schematic cross-sectional view of an embodiment of the floor cleaning machine according to the present invention is shown. Detailed Implementation

[0036] Figure 1 An embodiment of a floor cleaning machine 1 according to the present invention is shown, which is designed to perform an embodiment of the method for operating such a machine according to the present invention.

[0037] from Figure 1As can be seen, the floor cleaning machine 1 has a walking mechanism 5 including multiple wheels 3, which allows the floor cleaning machine 1 to move on the surface 7 to be cleaned. Therefore, in the embodiment shown here, the floor cleaning machine 1 has a drive unit 8 (not shown in detail) that drives the rear wheels 3 of the walking mechanism 5, thereby enabling the floor cleaning machine 1 to move automatically on the surface 7 to be cleaned. Furthermore, the floor cleaning machine 1 shown here is designed as a so-called robot, meaning it can move autonomously on the surface 7 to be cleaned without user guidance and automatically identify obstacles and determine its route accordingly.

[0038] However, the present invention is not limited to this type of robot, but can be applied to any type of floor cleaning machine 1, that is, it can also be applied to so-called riding machines or machines in which the user walks behind the machine.

[0039] For example, it can also be from Figure 1 As can be seen, the floor cleaning machine 1 has a cleaning device 9, which includes a cleaning element 11 designed herein as a rotating drive brush, which engages with the floor surface 7 to be cleaned during operation. The cleaning device 9 is also designed to lift the cleaning element 11 relative to the floor surface 7 to be cleaned, thereby preventing the cleaning element 11 from engaging with the floor surface 7 to be cleaned.

[0040] For example, it can also be from Figure 1 As can be seen, the cleaning device 9 has an outlet 13, which is connected to a cleaning fluid container 17 via a cleaning fluid line 15. The cleaning fluid container is housed in the housing 19 of the floor cleaning machine 1. A flow sensor 21 is provided in the cleaning fluid line 15, which forms a device that can detect the amount of cleaning fluid flowing through the cleaning fluid line 15 and supplied to the cleaning device 9 within a time interval.

[0041] In addition, a pump 23 is provided in the cleaning fluid line, which is designed to deliver the cleaning fluid from the cleaning fluid container 17 toward the outlet 13 and thus to the cleaning device 9. Here, the pump 23 can be preferably designed such that it also detects the amount of cleaning fluid delivered from the cleaning fluid container 17 toward the outlet 13 within a time interval. This can be a supplement to or replacement for the flow sensor 21 in this case. If both the pump 23 and the flow sensor 21 can detect the amount delivered in each time interval, then a redundant system is provided.

[0042] In addition to or supplementing the flow sensor 21 and pump 23, a first device may be provided in the liquid container 17, which is designed to detect the height of the cleaning fluid level 25 in the cleaning fluid container 17. This device has a guide element 27 that extends generally vertically within the cleaning fluid container 17 when the ground cleaning machine 1 is positioned on the horizontally extending ground surface 7 to be cleaned. A float 29 is guided on the guide element 27, and its position can be detected. Thus, based on the positional change of the float 29 in this float device 27, 29 over a time interval, the amount of cleaning fluid supplied to the cleaning device 9 during that time interval can also be determined.

[0043] Finally, as an alternative or supplement to the flow sensor 21, pump 23, or float devices 27, 29, a first pressure sensor 31 may also be provided in the bottom region of the cleaning fluid tank 17. The signal of the first pressure sensor is a measure of the gravitational pressure of the cleaning fluid in the cleaning fluid container 17. Thus, the first pressure sensor 31 can also be used to determine or detect the amount of cleaning fluid supplied to the cleaning device 9 within a certain time interval.

[0044] For example, it can also be from Figure 1 As can be seen, the floor cleaning machine 1 also has a waste container 33 within the housing 19. The top area of ​​this waste container is connected to the inlet of a suction device 35, which is driven by an electric motor 37. In a preferred embodiment, this suction device is a so-called suction turbine, in which the electric motor 37 drives a fan impeller to rotate. Therefore, the suction device is designed to apply negative pressure to the waste container 33 relative to the environment of the floor cleaning machine 1. Finally, the electric motor 37 is designed or equipped with a corresponding device to generate a signal that measures the current consumed by the electric motor 37. This generates a signal reflecting the level of motor current consumed by the electric motor 37 over a time interval.

[0045] In addition, from Figure 1 As can be seen, a second pressure sensor 39 and a third pressure sensor 41 are provided in the wastewater container 33. The second pressure sensor 39 is designed to detect the gravitational pressure of the wastewater in the bottom region of the wastewater container 33 and generate a corresponding signal. The third pressure sensor detects the pressure above the liquid level 43 in the wastewater container 33, where the pressure is reduced relative to the ambient pressure due to the pumping device 35. The liquid level 43 in the wastewater container 33 can then be determined in a known manner based on the signals from the second pressure sensor 39 and the third pressure sensor 41. Furthermore, the change in the liquid level 43 can be derived from this, and thus the amount of wastewater supplied to the wastewater container 33 within a certain time interval can be determined.

[0046] In this regard, it should be noted that the present invention is not limited to determining the liquid level 43 in the wastewater container 33 and thus the amount of wastewater supplied within a time interval by means of a pressure sensor. Alternative solutions, such as the use of a float, are also conceivable.

[0047] If from Figure 1 As can be seen, the top area of ​​the waste container 33 is connected to the waste collection device 47 via a waste pipe 45, which, in the preferred embodiment shown here, is designed as a so-called suction nozzle. The suction nozzle has a front sealing lip 49 and a rear sealing lip 51. The front sealing lip has a slit extending away from the area it contacts the surface 7 to be cleaned, while the rear sealing lip has no slit. The sealing lips 49, 51 and the suction nozzle extend generally across the width of the floor cleaner 1, and the area between the sealing lips 49, 51 is connected to the waste container 33 via the waste pipe 45, thus applying negative pressure to this area when the suction device 35 is in operation. This negative pressure ensures that any waste present on the surface 7 to be cleaned is sucked into the waste container 33.

[0048] If the wastewater pipe 45 is blocked or the gap between the sealing lips 49 and 51 of the wastewater extraction device 47 is completely filled with wastewater, preventing ambient air from entering the gap, then the extraction device 35 only needs to supply a small amount of air to maintain the negative pressure in the wastewater container 33. Consequently, in this situation, the motor current of the electric motor 37 driving the extraction device 35 will be reduced compared to normal operation.

[0049] Finally, it can be seen that the floor cleaning machine 1 has a controller 53, which is connected to the electric motor 37, float devices 27 and 29, pump 23, flow sensor 21, drive device 7 and pressure sensors 31, 39 and 41 via wiring so that the above devices can transmit their signals to the controller 53.

[0050] This signal connection allows the flow sensor 21, pump 23, float devices 27 and 29, and first pressure sensor 31 to transmit signals to the controller 53, which are measurements of the amount of cleaning fluid supplied from the cleaning fluid container 17 to the outlet 13 and thus to the cleaning device 9 during a first time interval. Similarly, the second pressure sensor 39 and the third pressure sensor 41 can also transmit signals to the controller 53, which are measurements of the amount of wastewater collected by the wastewater collection device 47 and discharged into the wastewater container 33 during a second time interval.

[0051] The floor cleaning machine 1 of the above embodiment can be operated in accordance with the methods described below.

[0052] The floor cleaning machine 1 moves across the surface 7 to be cleaned using a walking mechanism 5 and a drive unit 8, which is currently automated. The controller 53 also determines the route via (not shown) sensors, along which the floor cleaning machine 1 cleans the surface 7. Here, cleaning fluid is continuously supplied from the cleaning fluid container 17 to the area of ​​the cleaning unit 9 via the cleaning fluid line 15 using a pump 23. Dirt is removed from the surface to be cleaned by means of the driven cleaning element 11, while... Figure 1 The visible floor cleaning machine 1 moves further to the right, causing the cleaning fluid (and therefore the waste fluid) carrying dirt to reach the area of ​​the waste collection device 47. In parallel with the supply of cleaning fluid, the suction device 35, via its connected electric motor 37, also operates, creating a negative pressure in the waste container 33. Due to this negative pressure, the waste fluid reaching the area of ​​the waste collection device 47 and thus between the sealing lips 49, 51 is sucked away through the waste line 45 and discharged into the waste container 33, provided that the waste line 45 is not blocked or that the waste collection device 47 does not malfunction.

[0053] The following steps are always repeated during the movement of the ground cleaning machine 1 on the ground surface 7 and during the application of cleaning fluid and the removal of waste.

[0054] During the first time interval, the amount of cleaning fluid applied to the surface 7 to be cleaned is detected by means of flow sensor 21. Alternatively, this can be performed by means of pump 23, float devices 27, 29, or first pressure sensor 31 in the manner already described. The detection of this amount during the first time interval is based on signals transmitted to controller 53 in their respective cases. Here, the signals from flow sensor 21, pump 23, float devices 27, 29, and / or first pressure sensor 31 can be integrated into controller 53 during the first time interval, so that the integrated signal becomes a measure of the cleaning fluid applied to the surface 7 to be cleaned during the first time interval.

[0055] Similarly, the amount of wastewater discharged into the wastewater container 33 during the second time interval is detected using the second pressure sensor 39, the third pressure sensor 41, and the signals they generate during the second time interval. In this case, this amount can also be determined by integrating the individual signals. Here, in particular, the signal of the third pressure sensor 41 is subtracted from the signal of the second pressure sensor 39 to take into account the effect of the negative pressure present above the liquid surface 43 in the wastewater container 33.

[0056] The first and second time intervals are preferably offset from each other in time, so that the second time interval begins later than the first time interval. However, it is also possible that these time intervals are parallel in time. However, if the first alternative is used, it should be considered that, due to the movement of the floor cleaning machine 1, there will always be a certain time span between applying a certain amount of cleaning fluid and discharging the same amount.

[0057] Finally, during the second time interval, the motor current signal of the electric motor 37 of the pumping device 35 is also detected, which can also be generated by integrating the current signal in the controller 53.

[0058] If the signal reflecting the amount of cleaning fluid applied is greater than a first threshold, this indicates that the cleaning fluid was actually applied to the surface 7 to be cleaned. If the amount of waste fluid subsequently discharged during a second time interval is less than the second threshold, then although cleaning fluid was applied, not enough waste fluid was discharged. Therefore, if the amount of cleaning fluid applied during the first time interval is less than the first threshold and the amount of waste fluid discharged during the second time interval at the time of inspection is less than the second threshold, a fault exists, and the controller outputs a first error signal. Such a fault may be, for example, due to wear of the sealing lips 49, 51 of the waste fluid collection device 47, which is designed as a suction nozzle, thus failing to generate sufficient negative pressure in the suction nozzle, or a rupture or leak in the waste fluid conduit 45 between the waste fluid collection device 47 and the waste fluid container 33. This error signal can be used, for example, to stop the drive unit 8, thereby stopping the floor cleaning machine 1. This prevents a large area of ​​the surface to be cleaned from being treated with cleaning fluid but not being discharged. In addition, the first error signal can be used to shut down the pump 23.

[0059] In addition, check whether the amount of waste liquid discharged during the second time interval, or the signal generated based thereon, is below the third threshold. If simultaneously the motor current of electric motor 37, or the signal generated based thereon, is also below the fourth threshold, this indicates that the waste liquid line 45 or the waste liquid collection device 47 is blocked, and therefore no waste liquid can reach the waste liquid container 33. This is also a fault, in which case the controller 53 generates a second error signal, which can then be used to stop the drive device 8 and / or pump 23.

[0060] However, if the motor current signal is below the fourth threshold, but the signal of the amount of sewage discharged during the second time interval is above the third threshold, this indicates that the sewage collection device 47 is completely filled with sewage, and therefore airflow through the sewage pipe 45 cannot be formed. Therefore, in this case, the low motor current is not associated with a fault, and the controller 53 does not generate an error signal.

[0061] Therefore, embodiments of the operating method for the floor cleaning machine 1 according to the present invention can reliably detect faults such as residual waste liquid on the surface 7 to be cleaned. Furthermore, the parallel detection of motor current and the amount of waste liquid discharged allows the signal of the motor current of the electric motor 37 to also be used for fault determination.

[0062] List of reference numerals in the attached diagram:

[0063] 1. Floor cleaning machine

[0064] 3 wheels

[0065] 5. Walking mechanism

[0066] 7. Floor surface to be cleaned

[0067] 8. Drive unit

[0068] 9. Cleaning equipment

[0069] 11 Cleaning components

[0070] 13 Exports

[0071] 15 Cleaning fluid piping

[0072] 17. Cleaning solution container

[0073] 19. Shell

[0074] 21 Flow Sensor

[0075] 23 pumps

[0076] 25 Cleaning fluid level

[0077] 27. Guide elements

[0078] 29 Floats

[0079] 31 First pressure sensor

[0080] 33 Dirty liquid container

[0081] 35. Exhaust / discharge device

[0082] 37 Electric motor

[0083] 39 Second pressure sensor

[0084] 41 Third pressure sensor

[0085] 43. Sewage liquid level

[0086] 45. Sewage pipe

[0087] 47. Wastewater collection device

[0088] 49 Front sealing lip

[0089] 51 Rear sealing lip

[0090] 53 Controller

Claims

1. A method for operating a floor cleaning machine (1), wherein, The floor cleaning machine (1) has a cleaning liquid container (17), a waste liquid container (33), and a walking mechanism (5) for moving the floor cleaning machine (1) on the ground surface (7) to be cleaned. The floor cleaning machine (1) has a cleaning device (9) with cleaning elements (11) designed to engage with the floor surface (7) to be cleaned. The cleaning device (9) is connected to the cleaning liquid container (17) for supplying cleaning liquid to the cleaning device (9), and the cleaning device is designed to apply the cleaning liquid to the surface (7) to be cleaned. The floor cleaning machine (1) has a wastewater collection device (47) connected to a wastewater container (33) to discharge wastewater from the wastewater collection device (47) to the wastewater container, and the wastewater collection device is designed to collect wastewater from the surface (7) to be cleaned. The method comprises the following steps: - Move the floor cleaning machine (1) on the surface (7) to be cleaned. The method is characterized by further comprising the following steps: - During this movement, the amount of cleaning fluid supplied from the cleaning fluid container (17) to the cleaning device (9) within a first time interval is detected. - During this movement, the amount of sewage discharged from the sewage collection device (47) to the sewage container (33) within a second time interval is detected. - Compare the detected amount of cleaning fluid with a first threshold. - Compare the amount of detected contaminant with a second threshold. - If the detected amount of cleaning fluid is greater than the first threshold and the detected amount of contaminant is less than the second threshold, then a first error signal is output. The floor cleaning machine (1) has a pumping device (35) that applies negative pressure to the waste container (33) and has an electric drive motor (37) that is supplied with a voltage of a predetermined intensity during operation, so that the power supply current flows through the drive motor (37). Specifically, the intensity of the supply current is detected during the third time interval. The detected power supply current intensity is compared with a third threshold. The amount of detected contaminant is compared with a fourth threshold, and Specifically, when the intensity of the detected power supply current is less than the third threshold and the amount of detected contaminant is less than the fourth threshold, a second error signal is output.

2. The method according to claim 1, wherein, The floor cleaning machine (1) has a device designed to detect the amount of cleaning fluid supplied from the cleaning fluid container (17) to the cleaning device (9) within a first time interval, and The floor cleaning machine (1) has a device designed to detect the amount of sewage discharged from the sewage collection device (47) to the sewage container (33) during a second time interval.

3. The method according to claim 1 or 2, wherein, The floor cleaning machine (1) has a device designed to detect the intensity of the power supply current during a third time interval.

4. The method according to claim 1 or 2, wherein, The walking mechanism (5) of the floor cleaning machine (1) has a drive unit (8) designed to drive the walking mechanism, thereby causing the floor cleaning machine (1) to move on the surface (7) to be cleaned, and The drive unit (8) is shut down when the first error signal or the second error signal occurs.

5. The method according to claim 1 or 2, wherein, The floor cleaning machine (1) is designed to be an autonomous floor cleaning machine (1).

6. The method according to claim 1 or 2, wherein, The cleaning fluid container (17) is connected to the cleaning device (9) via a cleaning fluid pipeline (15) for supplying the cleaning fluid, and A flow sensor (21) is installed in the cleaning fluid pipeline (15) as a device for detecting the amount of cleaning fluid supplied during the first time interval.

7. The method according to claim 1 or 2, wherein, The cleaning fluid container (17) is connected to the cleaning device (9) via a cleaning fluid pipeline (15) for supplying the cleaning fluid, and A cleaning fluid pump (23) is provided in the cleaning fluid pipeline (15). The cleaning fluid pump is designed to detect the amount of cleaning fluid supplied to the cleaning device (9) during the first time interval, so that the pump (23) functions as a device for detecting the amount of cleaning fluid supplied from the cleaning fluid container (17) to the cleaning device (9) during the first time interval.

8. The method according to claim 1 or 2, wherein, A first device (27, 29) is provided for detecting the liquid level (25) in the cleaning fluid container, and The first device detects the change in the liquid level (25) in the cleaning fluid container (17) during the first time interval, thereby detecting the amount of cleaning fluid supplied during the first time interval.

9. The method according to claim 8, wherein, The first device (27, 29) for detecting the liquid level (25) in the cleaning fluid container (17) has a float (29), wherein the change in the position of the float is detected within the first time interval, thereby detecting the amount of cleaning fluid supplied within the first time interval.

10. The method according to any one of claims 1, 2, and 9, wherein, A second device is provided for detecting the liquid level (43) inside the wastewater container (33), and The second device detects the change in the liquid level (43) in the wastewater container (33) during the second time interval, thereby detecting the amount of wastewater discharged into the wastewater container (33) during the second time interval.

11. The method according to claim 10, wherein, The second device used to detect the liquid level (43) in the waste container is designed as a pressure sensor (39, 41).

12. A floor cleaning machine designed to perform the method according to any one of claims 1 to 11.

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