Cleaning device with fluid tank empty detection

Abstract

Various cleaning devices with fluid tank empty detection and methods related thereto are provided. In general, a cleaning device can be configured to determine whether a fluid container is empty using an electromotive force (EMF) at a fluid pump configured to pump fluid from the fluid container. When the fluid container becomes empty, fluid cannot be supplied from the cleaning device to a surface until more fluid is added to the fluid container. Thus, by determining whether the fluid container is empty, a user of the cleaning device may be made aware when the fluid container becomes empty and needs refilling (or replacement).

1 . A method comprising:
 causing, using a controller, a fluid pump of a cleaning device to pump a fluid from a fluid supply tank for delivery to a surface to be cleaned by the cleaning device, the fluid pump including a motor configured to drive the pumping of the fluid and to generate an electromotive force (EMF); and   determining, using the controller and based on the generated EMF, whether the fluid supply tank is substantially empty.   
     
     
         2 . The method of  claim 1 , further comprising, using the controller and in response to determining that the fluid supply tank is substantially empty, causing a user notification to be provided via the cleaning device indicating that the fluid supply tank is substantially empty. 
     
     
         3 . The method of  claim 1 , wherein determining whether the fluid supply tank is substantially empty includes comparing, using the controller, EMF data received by a processor from the fluid pump with a predetermined threshold EMF value. 
     
     
         4 . The method of  claim 3 , wherein the predetermined threshold EMF value is a preset value that does not change. 
     
     
         5 . The method of  claim 3 , further comprising:
 determining, using the controller, whether the EMF data is outside of a predetermined range;   wherein, if the EMF data is outside of the predetermined range, the controller is configured to change the predetermined threshold EMF value to a new predetermined threshold EMF value, and if the EMF data is not outside of the predetermined range, the predetermined threshold EMF value is left unchanged.   
     
     
         6 . The method of  claim 5 , further comprising calculating, using the controller, the new predetermined threshold EMF value based on the EMF data. 
     
     
         7 . The method of  claim 1 , further comprising causing the fluid pump to turn off in response to a user input to the cleaning device. 
     
     
         8 . A method comprising:
 operating a fluid pump of a cleaning device to pump fluid from a fluid supply tank, the fluid pump including a motor that generates an electromotive force (EMF) during operation; stopping the fluid pump;   receiving, at a controller, a signal indicative of the EMF generated by the motor after the fluid pump has been stopped; and   determining, based on the received signal, whether the fluid supply tank is substantially empty.   
     
     
         9 . The method of  claim 8 , further comprising, in response to determining that the fluid supply tank is substantially empty, causing a user notification to be provided via the cleaning device indicating that the fluid supply tank is substantially empty. 
     
     
         10 . The method of  claim 8 , wherein determining whether the fluid supply tank is substantially empty includes comparing EMF data from the received signal with a predetermined threshold EMF value. 
     
     
         11 . The method of  claim 10 , wherein the predetermined threshold EMF value is a preset value that does not change. 
     
     
         12 . The method of  claim 10 , further comprising:
 determining whether the EMF data is outside of a predetermined range;   wherein, if the EMF data is outside of the predetermined range, the controller is configured to change the predetermined threshold EMF value to a new predetermined threshold EMF value, and if the EMF data is not outside of the predetermined range, the predetermined threshold EMF value is left unchanged.   
     
     
         13 . The method of  claim 12 , further comprising calculating the new predetermined threshold EMF value based on the EMF data. 
     
     
         14 . The method of  claim 8 , wherein the motor includes a rotor and a stator, and wherein the EMF is generated by rotation of the rotor after the fluid pump has been stopped. 
     
     
         15 . A method, comprising:
 activating a fluid pump having a motor with a rotor to pump fluid from a fluid supply tank;   deactivating the fluid pump;   monitoring electromotive force (EMF) generated by the motor during a period after deactivation while the rotor continues rotating due to inertia;   comparing the monitored EMF with a predetermined threshold EMF value; and   determining that the fluid supply tank is substantially empty when the monitored EMF exceeds the predetermined threshold EMF value.   
     
     
         16 . The method of  claim 15 , further comprising, in response to determining that the fluid supply tank is substantially empty, causing a user notification to be provided via the cleaning device indicating that the fluid supply tank is substantially empty. 
     
     
         17 . The method of  claim 16 , wherein the user notification includes at least one of a visual indicator and an audible indicator provided via a user interface of the cleaning device. 
     
     
         18 . The method of  claim 15 , wherein monitoring the EMF includes waiting a predetermined period of time delay after deactivating the fluid pump before beginning to monitor the EMF to avoid noise immediately after deactivation. 
     
     
         19 . The method of  claim 18 , wherein monitoring the EMF further includes reading EMF data from the motor on a regular periodic basis after the predetermined period of time delay. 
     
     
         20 . The method of  claim 15 , wherein the predetermined threshold EMF value is about halfway between an EMF value when the fluid supply tank is substantially empty and an EMF value when the fluid supply tank is not substantially empty.