Surface engagement sensing for a surface cleaning apparatus

Abstract

A surface cleaning apparatus includes an air pathway having a suction inlet. A motor is configured to generate airflow through the air pathway. One or more operating parameters of the motor may vary when the suction inlet is engaged or disengaged with a surface. A power level of the motor may be controlled based, at least on part, on changes in one or more operating parameters of the motor.

What is claimed is: 
     
         1 . A surface cleaning apparatus comprising:
 a debris holding container;   a suction inlet;   an air pathway at least partially defined by the debris holding container and the suction inlet;   a motor configured to drive a fan to generate airflow through the air pathway, the motor defining a first power usage profile corresponding to a cleaning engaged state, and a second power usage profile corresponding to a cleaning disengaged state, wherein the second power usage profile is not identical to the first power usage profile;   an electrical power source configured to provide electrical power to the motor; and   a controller in operable communication with the motor, wherein the controller is configured to:
 detect a shift from the first power usage profile to the second power usage profile based, at least in part, on a change in at least one power metric; and 
 reduce power to the motor when a shift from the first power usage profile to the second power usage profile is detected. 
   
     
     
         2 . The surface cleaning apparatus of  claim 1 , wherein:
 the controller is configured to:
 detect a shift from the second power usage profile to the first power usage profile based, on at least in part, on a change in at least one power metric; and 
 increase power to the motor when a shift from the second power usage profile to the first power profile usage is detected. 
   
     
     
         3 . The surface cleaning apparatus of  claim 1 , wherein:
 the control system is configured to increase power to the motor after a delay period if the controller determines that predefined debounce criteria are satisfied.   
     
     
         4 . The surface cleaning apparatus of  claim 3 , wherein:
 the delay period comprises a first delay period; and   the controller is configured to turn off power to the motor after a second delay period that is greater than the first delay period.   
     
     
         5 . The surface cleaning apparatus of  claim 1 , wherein:
 the power metric comprises at least one operating parameter selected from the group consisting of electric current of the motor, electric power of the motor, a rate of change of electric current of the motor, and a rate of change of electric power of the motor.   
     
     
         6 . The surface cleaning apparatus of  claim 1 , wherein:
 the power metric includes at least a selected one of an RPM of the motor and an electric current of the motor.   
     
     
         7 . The surface cleaning apparatus of  claim 1 , wherein:
 the controller is configured to:
 utilize a change of the power metric over a predefined time interval to determine if the suction inlet has moved into engagement with a surface and/or moved out of engagement with a surface. 
   
     
     
         8 . A cleaning apparatus comprising:
 a battery;   a motor that is operably connected to the battery;   an air conduit having a suction inlet;   an impeller in fluid communication with the air conduit and operably connected to the motor whereby the motor can be actuated to cause the impeller to create a suction at the suction inlet;   a controller that is configured to:
 cause the motor to operate in first and second modes, wherein the second mode provides increased suction at the suction inlet relative to the first mode when the inlet is engaging a surface; 
 cause the motor to switch from the first mode to the second mode, based at least in part, on first engagement criteria; 
 cause the motor to switch from the second mode to the first mode, based at least in part, on second engagement criteria; and: 
 wherein the first and second engagement criteria comprise changes in electrical power used by the motor associated with engagement of the suction inlet with a surface, whereby the controller causes the motor to switch from the first mode to the second mode if the suction inlet is brought into engagement with a surface, and causes the motor to switch from the second mode to the first mode if the suction inlet is disengaged from a surface. 
   
     
     
         9 . The cleaning apparatus of  claim 8 , wherein:
 the controller is configured to operate the motor at first and second power levels in the first and second modes, respectively; and   the second power level is greater than the first power level.   
     
     
         10 . The cleaning apparatus of  claim 8 , wherein:
 the first engagement criteria comprises a rate of change in electrical power used by the motor that is greater than a predefined first threshold rate of change in electrical power of the motor.   
     
     
         11 . The cleaning apparatus of  claim 8 , wherein:
 the controller is configured to repeatedly determine electrical power used by the motor when in the first and/or second modes based, at least in part, on the voltage and electrical current of the motor.   
     
     
         12 . The cleaning apparatus of  claim 8 , wherein:
 when in the first mode the controller is configured to: 1) determine an average rate of change in electrical power used by the motor utilizing a plurality of individual rates of change in electrical power used by the motor over a period of time, and: 2) compare the average rate of change in electrical power used by the motor to the first threshold rate of change in electrical power used by the motor, and: 3) determine that the first engagement criteria is satisfied if the average rate of change in electrical power used by the motor is greater than or equal to the predefined first threshold rate of change in electrical power used by the motor.   
     
     
         13 . The cleaning apparatus of  claim 8 , wherein:
 when in the first mode the controller is configured to: 1) determine the individual rates of change in electrical power used by the motor utilizing a difference in electrical power used by the motor over an increment of time, and: 2) store the individual rates of change in electrical power used by the motor in a circular buffer whereby a plurality of individual rates of change in electrical power used by the motor are stored in the circular buffer; and   the controller is configured to determine the average rate of change in electrical power used by the motor utilizing the plurality of individual rates of change in electrical power used by the motor stored in the buffer.   
     
     
         14 . The cleaning apparatus of  claim 8 , wherein:
 the first mode comprises a LOW power mode;   the second mode comprises a HIGH power mode in which motor power is increased relative to the LOW power mode;   the controller is configured to implement a first debounce after initially determining that the first engagement criteria is satisfied to: 1) delay, by a first debounce time, switching the motor from the LOW power mode to the HIGH mode, and: 2) switch from the LOW power mode to the HIGH power mode after the first debounce time if the first engagement criteria is satisfied during the first debounce time.   
     
     
         15 . The cleaning apparatus of  claim 8 , wherein:
 the second engagement criteria comprises a rate of change in electrical power used by the motor that is greater than a predefined second threshold rate of change in electrical power used by the motor;   the predefined second threshold rate of change in electrical power used by the motor is greater than the predefined first threshold rate of change in electrical power used by the motor.   
     
     
         16 . The cleaning apparatus of  claim 8 , wherein:
 when in the second mode the controller is configured to: 1) determine an average rate of change in electrical power used by the motor utilizing a plurality of individual rates of change in electrical power used by the motor over a period of time, 2) compare the average rate of change in electrical power used by the motor to the second threshold rate of change in electrical power used by the motor, and: 3) determine that the second engagement criteria is satisfied if the average rate of change in electrical power used by the motor is greater than or equal to the predefined second rate of change in electrical power used by the motor.   
     
     
         17 . The cleaning apparatus of  claim 16 , wherein:
 when in the second mode the controller is configured to: 1) determine the individual rates of change in electrical power used by the motor utilizing a difference in electrical power used by the motor over an increment of time, and: 2) store the individual rates of change in electrical power used by the motor in a circular buffer whereby a plurality of individual rates of change in electrical power used by the motor are stored in the circular buffer; and   the controller is configured to determine the average rate of change in electrical power used by the motor utilizing the plurality of individual rates of change in electrical power used by the motor stored in the buffer.   
     
     
         18 . The cleaning apparatus of  claim 14 , wherein:
 the first mode comprises a LOW power mode;   the second mode comprises a HIGH power mode in which motor power is increased relative to the LOW power mode;   the controller is configured to implement a second debounce after initially determining that the second engagement criteria is satisfied to: 1) delay, by a second debounce time, switching the motor from the HIGH power mode to the LOW power mode; and: 2) switch from the HIGH power mode to the LOW power mode after the second debounce time if the second engagement criteria is satisfied during the second debounce time.   
     
     
         19 . The cleaning apparatus of  claim 18 , wherein:
 the second debounce time is greater than the first debounce time.   
     
     
         20 . The cleaning apparatus of  claim 18 , wherein:
 the controller is configured to determine electrical current used by the motor and/or power used by the motor while the motor is in the LOW power mode and the suction inlet is disengaged from a surface to determine a baseline LOW disengaged power criteria comprising electrical current and/or power;   the controller is configured to determine electrical current used by the motor and/or electrical power used by the motor while the motor is in the HIGH power mode and the suction inlet is disengaged from a surface to determine a baseline HIGH disengaged power criteria comprising electrical current and/or power;   the controller is configured to switch from the LOW power mode to the HIGH power mode if: 1) the first engagement criteria is satisfied, and: 2) the baseline LOW disengaged power criteria is satisfied; and   the controller is configured to switch from the HIGH power mode to the LOW power mode if: 1) the second engagement criteria is satisfied, and: 2) the baseline HIGH disengaged power criteria is satisfied.   
     
     
         21 . The cleaning apparatus of  claim 20 , wherein:
 the controller is configured to determine the baseline LOW disengaged power criteria and/or baseline HIGH disengaged power criteria during initial calibration, whereby the controller is configured to: 1) initially operate the motor in HIGH power mode after the motor is turned ON, and: 2) determine the baseline HIGH disengaged power criteria while the motor is operating in HIGH power mode; and   the controller is configured to: 1) initially operate the motor in LOW power mode after the motor is turned ON, and: 2) determine the baseline LOW disengaged power criteria while the motor is operating in LOW power mode.   
     
     
         22 . The cleaning apparatus of  claim 21 , wherein:
 the controller is configured to update the baseline LOW disengaged power criteria during use by measuring electrical current used by the motor and/or electrical power used by the motor while the motor is in the LOW power mode after changing from the HIGH power mode to the LOW power mode after the suction inlet is disengaged from a surface to determine an updated baseline LOW disengaged power criteria.   
     
     
         23 . The cleaning apparatus of  claim 22 , wherein:
 the baseline LOW disengaged power criteria comprises a range of electrical current about an electrical current measured while the motor is in LOW power mode and the suction inlet is disengaged from a surface;   the baseline HIGH disengaged power criteria comprises a range of electrical current about an electrical current measured while the motor is in HIGH power mode and the suction inlet is disengaged from a surface;   the controller is configured to continue operating in the HIGH power mode unless measured current is within the HIGH disengaged range of electrical current, even if the second engagement criteria is satisfied; and   the controller is configured to continue operating in the LOW power mode unless measured current is outside of the LOW disengaged range of electrical current, even if the first engagement criteria is satisfied.   
     
     
         24 . The cleaning apparatus of  claim 8 , including:
 a user input feature that allows a user to input an override; and wherein:   the controller is configured to continue operating the motor in HIGH power mode when the suction inlet is disengaged from a surface if an override has been input.   
     
     
         25 . An apparatus for cleaning surfaces comprising:
 an air passageway having a suction inlet that is configured to engage a surface to clean the surface;   an impeller in fluid communication with the air passageway;   a motor operably connected to the impeller, whereby the motor causes air to flow in the air passageway to create suction at the suction inlet;   a controller that is configured to cause the apparatus to selectively operate in a first mode or a second mode, wherein suction at the suction inlet is increased in the second mode relative to suction at the suction inlet in the first mode;   and wherein the controller is configured to change from the first mode to the second mode and/or from the second mode to the first mode based, at least in part, on power change criteria, wherein the power change criteria comprises a rate of change of electrical power of the motor.   
     
     
         26 . The apparatus of  claim 25 , wherein:
 the controller is configured to switch from the second mode to the first mode if the rate of change of electrical power used by the motor is below a predefined threshold.   
     
     
         27 . The apparatus of  claim 26 , wherein:
 the controller is configured to continue operating in the second mode if electrical current and/or power used by the motor is consistent with an electrical current and/or power that is expected, according to predefined criteria, when the suction inlet is engaging a surface in the second mode, even if the power change criteria is satisfied.   
     
     
         28 . The apparatus of  claim 27 , wherein:
 the power change criteria comprises first and second power change criteria, wherein the first power change criteria comprises a first threshold rate of change of electrical power used by the motor, and the second power change criteria comprises a second threshold rate of change of electrical power used by the motor, wherein the first threshold rate of change of electrical power used by the motor is less than the second threshold rate of change of electrical power used by the motor;   and wherein the controller is configured to switch from the first mode to the second mode based, at least in part, on a comparison of a measured rate of change of electrical power used by the motor to the first threshold rate of change of electrical power used by the motor.