Power control method for motor of air mobile equipment

Abstract

A method of controlling an input power of a motor of an air mobile device includes performing a measurement process to determine a first value of an operating parameter of the motor. The operating parameter is an operating pressure of the motor or an airflow velocity through the motor. The method includes performing a determination process to determine an inlet limit value of the air mobile device based on a first value of an operating parameter of the motor and a first predetermined relationship between the operating parameter value of the motor and the inlet limit value of the air mobile device. The method includes controlling an input power of the motor based on the determined value of the entry limit.

Description

Technical Field

[0001] The present invention relates to a method of controlling input power to a motor of an air moving device, a set of machine-readable instructions for performing the method, and an air moving device having a memory including such instructions and a processor configured to perform the method by executing the instructions. Background Art

[0002] It is generally desirable to improve air moving devices, such as vacuum cleaners, in a variety of ways. For example, improvements may be needed in terms of efficiency, manufacturing costs, flexibility of use, and reliability. Summary of the invention

[0003] According to a first aspect of the present invention, a method for controlling the input power of a motor of an air moving device is provided, the method comprising: performing a measurement process to determine a first value of an operating parameter of the motor, wherein the operating parameter is an operating pressure of the motor or an air flow velocity through the motor; performing a determination process to determine an inlet restriction value of the air moving device based on the first value of the operating parameter of the motor and a first predetermined relationship between the operating parameter value of the motor and the inlet restriction value of the air moving device; and controlling the input power of the motor based on the determined inlet restriction value.

[0004] Controlling the input power of the motor based on a determined value of the inlet limit can allow the input power of the air moving device to adapt to an appropriate level of the inlet limit value. For example, the appropriate level can be a level that allows the task of the air moving device to be performed effectively and efficiently. For example, in the case of a low inlet limit value, a lower motor input power may be required to perform a given task, while in the case of a high inlet limit value, a higher input power may be required to perform a given task. The method can allow dynamic control of the motor input power, for example, increasing the motor input power when the inlet limit value is high and reducing the motor input power when the inlet limit value is low. Determining the value of the inlet limit based on an operating parameter of the motor (e.g., operating pressure) can allow the inlet limit to be reliably determined based on an observable physical parameter without directly measuring the inlet limit. The method can allow the inlet limit to be used when a passive tool that does not have any sensing device that allows the inlet limit to be inferred is attached to the device. The method can avoid the need for additional sensors or processing to directly measure the inlet limit.

[0005] The operating parameter may be an operating pressure, and the measuring process may include determining a first value of the motor operating parameter based on: an ambient pressure measurement; and a motor inlet pressure measurement during operation of the motor.

[0006] Determining a first value of an operating parameter based on an ambient pressure measurement and a motor inlet pressure measurement during motor operation can provide that the first operating parameter value is an operating pressure differential that is related to the inlet restriction in a reliable and accurate manner. It can also allow measurements made for other purposes related to operation of the air moving device, such as ambient pressure, to be used to obtain the first value of the operating parameter of the motor.

[0007] The ambient pressure measurement and the motor inlet pressure measurement may be measured by a single pressure sensor at different times.

[0008] Measuring the ambient pressure measurement and the motor inlet pressure measurement at different times by a single pressure sensor may allow a first value of an operating parameter to be obtained by using a single pressure sensor, which may provide a cost and space efficient method of determining the operating pressure.

[0009] The measurement process may include determining a first value of an operating parameter of the motor based on: a first pressure measurement of pressure at a first location in a motor assembly in which the motor is located; and a second pressure measurement of pressure at a second location in the motor assembly; wherein the second location is downstream of the first location.

[0010] Using a pressure measurement upstream of the motor and a pressure measurement downstream of the motor may allow obtaining an accurate and reliable measurement of an operating parameter in a simple manner.

[0011] The first predetermined relationship may relate the operating parameter value of the motor and the one or more other parameter values ​​to an inlet restriction value of the air moving device.The determining process may include determining the inlet restriction value based on one or more corresponding further parameter values ​​of the one or more further parameters.

[0012] This may allow the inlet restriction value to be determined to compensate for other parameters, such as other measurable or determinable parameters associated with the air moving device.

[0013] The one or more additional parameters may include one or more of: ambient pressure; ambient temperature; motor input power; and manufacturing tolerances of the air moving device.

[0014] These parameters may be readily determined, such as by using sensors, or may be predetermined, such as by a calibration procedure.In determining the inlet restriction, compensation of these parameters may provide a first value of the motor operating parameter to be effectively mapped to the inlet restriction value.

[0015] The determining process can include determining a first normalized value of the operating parameter by normalizing the first value of the operating parameter using one or more corresponding values ​​of one or more other parameters; and determining an inlet restriction value of the air moving device based on the normalized operating parameter.

[0016] Normalizing the operating parameter value by using one or more additional parameters can provide an efficient way to obtain an operating parameter value that maps well to an inlet restriction value of the air moving device. For example, normalizing a first value of an operating parameter can reduce the dimensionality in a lookup performed based on a mapping between a normalized value of the operating parameter and an inlet restriction value.

[0017] The one or more additional parameters may include a filter loading value for the air moving device filter.

[0018] This may allow compensation for the filter loading level of the air moving device filter when determining the inlet restriction level. This may also allow maintaining a reliable mapping of the operating parameter value to the inlet restriction value even if the filter loading level changes during use of the air moving device. The filter loading may be the loading level of a filter that filters particulate matter from the air flow through the motor. For example, the filter loading may be the loading level of a pre-motor filter. The loading level may define a dynamic restriction to the air flow provided by the filter, for example due to dust collected by the filter obstructing the air flow.

[0019] The determining process may include determining a filter loading value.

[0020] This may allow a reliable current value of the filter loading value to be obtained during operation of the air moving device. This may contribute to the accuracy of the mapping of operating parameter values ​​to inlet restriction values.

[0021] Determining the filter load value may include performing a second measurement process, the second measurement process including determining a first value of a second operating parameter of the air moving device, the first value being the value of the second operating parameter when the air moving device is operating with a first inlet restriction; and performing a second determination process to determine the filter load value, the determination process including determining the filter load value based on the first value of the second operating parameter and a second predetermined relationship, the second predetermined relationship associating the second operating parameter value with the filter load value for the air moving device operating with the first inlet restriction.

[0022] This may allow an accurate value of filter loading to be obtained without directly measuring the filter loading level. For example, a value of the filter loading level may be obtained without additional sensors and processing that may be used to determine a filter loading value based on measurements of filter upstream and downstream pressures.

[0023] The second operating parameter may be: an operating pressure of a motor of the air moving device; a speed of the motor of the air moving device; or an air flow rate through the motor of the air moving device.

[0024] The second operating pressure of the motor or the motor speed of the air moving device may be correlated to the filter loading value, and this correlation may be used to obtain the filter loading value.

[0025] The second operating parameter may be the same as the operating parameter mentioned above. Using the same operating parameter may allow the value already obtained as part of the method of determining the inlet restriction value to also be used to obtain the filter loading value. The motor speed of the air moving device may also be a parameter obtained for use in a monitoring or control program for the device, so using this parameter to estimate the filter loading may be effective in not requiring additional sensors or additional processing to obtain the measurement.

[0026] Determining the first value of the second operating parameter may include: determining a plurality of values ​​of the second operating parameter; determining a distribution of the plurality of values ​​of the second operating parameter; determining a first property of the distribution; and determining the first value of the second operating parameter based on the first property of the distribution.

[0027] This may provide an efficient way of obtaining a second operating parameter value that maps well to the filter loading value. By determining the first value based on the distribution properties of the second operating parameter value, predetermined information about the probability of an inlet restriction value of the air moving device during operation may be taken into account in order to make the first value correspond to a predetermined value of the inlet restriction.

[0028] A first property of a distribution may be the minimum value in the distribution.

[0029] The minimum value in the distribution can be determined efficiently and can be well correlated with the filter load value.

[0030] The controlling may include regulating the motor input power according to a set curve relating motor input power values ​​to inlet limit values.

[0031] This may allow the input power to be controlled in a predetermined manner based on the determined value of the inlet limit so as to provide a suitable input power for the determined value of the inlet limit.

[0032] The set curve may be a continuous curve.

[0033] This can dynamically adjust the input power at a fine level of granularity based on the determined values ​​of the inlet limits. This can allow the air moving device to operate efficiently with input power precisely matching all inlet limit values.

[0034] The setting curve may include a plurality of discrete power levels, each power level corresponding to a respective range of inlet limit values.

[0035] This can provide input power that is dynamically adjusted at a lower level of granularity. For example, this can allow the input power to remain consistent with small, determined changes in the inlet limit while changing to meet large, determined changes in the inlet limit. This can provide good efficiency levels while presenting a consistent experience to the user of the air moving device during small changes in the inlet limit during operation.

[0036] The method may include performing the measuring process, the determining process, and the controlling a plurality of times during operation of the air moving device.

[0037] For example, this may include continuously performing the method to continuously control the input power.This may allow the device to dynamically adapt to changes in the determined value of the inlet limit.

[0038] According to a second aspect of the invention, there is provided a set of machine readable instructions which, when executed by a processor of an air moving device, cause the air moving device to perform a method according to the first aspect of the invention.

[0039] According to a third aspect of the present invention, there is provided an air moving device, comprising: a processor; and a memory comprising a set of machine-readable instructions, which, when executed by the processor, cause the processor to perform the method according to the first aspect of the present invention.

[0040] The air moving device may be a vacuum cleaner.

[0041] Where appropriate, optional features of one aspect of the invention may be equally applied to other aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will now be described, by way of example only, with reference to the following drawings, in which:

[0043] Figure 1 A schematic diagram showing an example motor assembly of an air moving device;

[0044] Figure 2 An example of an air moving device is shown;

[0045] Figure 3 is a flow chart representing a method of controlling input power to a motor of an air moving device;

[0046] Figure 4 An example of a graph showing operating pressure values ​​and inlet restriction values ​​in an air moving device;

[0047] Figure 5 Other examples of graphs showing operating pressure values ​​and inlet restriction values;

[0048] Figures 6A to 6C An example power control curve for an air moving device is schematically shown;

[0049] Figure 7 is a flow chart representing a method of determining a filter loading value for an air moving device;

[0050] Figure 8 schematically illustrates aspects of an example method of determining a filter loading value;

[0051] Fig. 9 Schematically shows Figure 8 Other aspects of the example methods shown;

[0052] Fig.10 Schematically shows Figure 8 and 9 Other aspects of the example methods shown;

[0053] Fig.11A and 11B Shows Figures 8 to 10 Further aspects of the example methods shown in;

[0054] Fig.12 A schematic diagram showing another example motor assembly of an air moving device;

[0055] Fig.13 A schematic diagram showing another example motor assembly of an air moving device;

[0056] Fig.14 a schematic diagram showing certain components of a motor assembly of an air moving device according to an example; and

[0057] Fig.15 A schematic diagram is shown of certain components of an example motor assembly of an air moving device according to another example. DETAILED DESCRIPTION

[0058] Figure 1 An example schematic diagram of a motor assembly 100 of an air moving device is shown. The motor assembly 100 includes a set of coils 102, a shaft 104 on which magnets (not shown) are mounted, a bearing 106, and an impeller 108. The motor assembly 100 includes a motor air inlet 110 and an air outlet / diffuser 112. The motor assembly includes a circuit board 114 on which sensors, an ambient temperature sensor 116, and a first pressure sensor 118 are mounted. The motor assembly 100 includes a housing 124 in which other components are housed. The motor assembly 100 also includes a pre-motor filter 126 for filtering air that is drawn into the motor during use.

[0059] Figure 2An exemplary air moving device 200 including a motor assembly 100 is shown. The air moving device 200 is a vacuum cleaner. The vacuum cleaner 200 includes an inlet pipe 202, and a tool 204 is attached to the distal end of the inlet pipe 202. The tool 204 is used to engage with a surface to be cleaned by the vacuum cleaner and includes an air inlet (not shown) leading to the vacuum cleaner 200. The tool 204 can be active, including one or more mechanically operated components, such as a rotating brush bar, to assist in the cleaning task. Alternatively, the tool 204 can be passive and does not include any such mechanically operated components. However, a passive tool can include elements such as bristles or the like to help complete the cleaning task. In an example, the inlet pipe 202 or a portion thereof can be removable. When the inlet pipe 202 or a portion thereof is removed, a tool such as a passive tool can be attached to the device 200. The vacuum cleaner 200 also includes a dust separation chamber 206, which can be, for example, a cyclone chamber. The vacuum cleaner 200 also includes a processor 208 and a memory 210 for storing machine-readable instructions executed by the processor 208 to control the operation of components of the vacuum cleaner 200 including the motor 100. The machine-readable instructions, when executed, may cause the processor 208 to perform any of the example methods described herein.

[0060] In use, the motor of the motor assembly 100 draws air into the air moving device 200 through the air inlet, through the air moving device 200, and out of the exhaust port. The air is drawn through the device 200 along the air flow path 128, which passes through the inlet duct 202, the dust separation chamber 206, the motor assembly 100, and leaves the device 200 through the exhaust port.

[0061] Back to Figure 1 When the motor is used in the air moving device 200, current is passed through the coil 102, so that a changing magnetic field is generated. The changing magnetic field is configured to act on the magnets on the shaft 104 to rotate the shaft 104 about its longitudinal axis. This in turn rotates the impeller 108. Air driven by the impeller 108 is drawn into the air moving device 200 along the air flow path 128. The air flow path 128 enters the motor assembly 100, passes through the pre-motor filter 126 that removes particulate matter from the air, and enters the housing 124 through the air inlet 110. The air flow path 128 continues through the motor to the impeller 108, and after passing through the impeller 108, leaves the motor assembly 100 through the air outlet 112.

[0062] Figure 3 A flow chart representation of an example method 300 of controlling input power to a motor of an air moving device, such as a vacuum cleaner, is shown.

[0063] The method 300 includes, at block 302, performing a measurement process to determine a first value of an operating parameter of a motor. The operating parameter may be an operating pressure or an air flow rate.

[0064] The operating pressure of the motor is the air pressure associated with the motor when the motor is operating, i.e., when the motor is running. The operating pressure can be related to the air pressure at one or more locations along the airflow path 128. The operating pressure can be an air pressure difference. The operating pressure can be, for example, a pressure difference between an upstream and downstream location in the motor assembly along the airflow path 128.

[0065] In another example, the operating pressure is the difference between a first pressure measured when the motor is not running and a second pressure measured when the motor is running. The first pressure and the second pressure can be measured at the same location. The value of the operating pressure can be obtained, for example, by determining the difference between an ambient pressure measurement obtained when the motor is not running (for example, before starting the air moving device 200) and a pressure measurement obtained during motor operation. In some examples described herein, such an operating pressure is referred to as δ-P. The pressure measurement performed during motor operation can be performed, for example, at the air inlet 110. Alternatively, it can be measured at the air outlet of the motor. In some examples, the pressure measurement for obtaining the operating pressure value can be performed by the same pressure sensor. This allows the use of a single pressure sensor to obtain the operating pressure value, which can save cost and space.

[0066] Airflow rate is the speed at which air drawn in by the operation of the motor flows through the motor in use.

[0067] Examples of methods of obtaining operating pressure measurements and air flow velocity measurements are described in more detail below.

[0068] At block 304 , method 300 includes performing a determination process to determine an inlet restriction value for air moving device 200 based on a first value of an operating parameter of the motor and a first predetermined relationship between the operating parameter value of the motor and the inlet restriction value for air moving device 200 .

[0069] The inlet restriction value of the air moving device 200 defines the restriction level acting on the air inlet through which air flows into the device 200. The level of inlet restriction can vary based on various factors, such as obstacles that hinder the flow of air into the device 200. For example, the inlet restriction can vary depending on the type of surface that the vacuum cleaner 200 is used to clean. For example, a carpeted surface or similar surface may have a greater restriction on the airflow entering the vacuum cleaner 200 than a smooth surface such as a wood or tile surface. The inlet restriction value can also vary depending on the type of tool attached to the vacuum cleaner 200. For example, different tools can have different geometries, thereby restricting the airflow entering the vacuum cleaner 200 by different amounts. For example, different tools can have different air inlet diameters. In addition, some tools may include elements that hinder the airflow into the device 200, such as bristles for cleaning carpets, while other tools may not include such elements.

[0070] In some examples, it may be impossible or impractical to directly measure the inlet restriction of air moving device 200. Therefore, according to the examples described herein, the operating parameter value of the motor is measured and used to determine the inlet restriction value of device 200. The first predetermined relationship can be defined according to a curve that relates the operating parameter value of the motor to the inlet restriction value of air moving device 200.

[0071] The predetermined relationship between the operating parameter value and the inlet restriction value can be obtained, for example, through a calibration process. The calibration process can include, for example, operating the device 200 under known operating conditions, including known values ​​of the inlet restriction, and measured values ​​of the operating parameter. This can be achieved by operating the device 200 with an orifice plate having orifices of different diameters that restrict airflow into the device 200. The inlet restriction value of the device in operation can be defined based on the diameter of the orifice that will provide the same level of restriction to the airflow into the device 200. For example, when used to clean carpet surfaces, the vacuum cleaner 200 can be operated at a high level of inlet restriction, which can be equivalent to operating under known conditions where the orifice plate has a small diameter orifice that restricts airflow into the vacuum cleaner 200. Conversely, when cleaning wood surfaces, the vacuum cleaner 200 can be operated at a lower level of inlet restriction, equivalent to the inlet restriction presented by the larger diameter orifice.

[0072] The first predetermined relationship may associate the operating parameter value of the motor and one or more other parameter values ​​with the inlet restriction value of the air moving device. The inlet restriction value may then be determined based on the first value of the operating parameter and the corresponding values ​​of the one or more other parameters. The other parameters may be parameters of the air moving device 200 that affect the operating pressure value that is measured for a given inlet restriction value. For example, different values ​​of parameters such as ambient pressure, ambient temperature, motor input power, filter loading of the motor filter, and manufacturing tolerances of the air moving device may result in different operating parameter values ​​for the same inlet restriction value.

[0073] Ambient pressure and ambient temperature form part of the external conditions under which the device 200 operates. In some examples, ambient pressure may be measured by first pressure sensor 118 before the motor is started. Ambient temperature may be measured by temperature sensor 116. Motor input power is the power used to drive the motor.

[0074] The motor input power may be controlled by processor 208 and supply DC or AC power, for example, from a battery (not shown) of device 200 or from a mains supply. The motor input power may control the suction power of the air moving device.

[0075] The filter load may be the load level of the filter that filters particulate matter from the airflow through the motor. For example, the filter load may be the load level of the pre-motor filter 126. Alternatively, the filter load may be the level of loading the post-motor filter, or the load levels of multiple filters (e.g., pre-motor filter and post-motor filter) may be considered. The load level of the filter may determine how much dust the filter has collected. In an example, this may be represented by the amount of dust that the filter may collect before it is considered to need replacement or cleaning. For example, a filter load of 100% may indicate that the filter has collected a certain amount of dust and is therefore considered to need replacement or cleaning. A filter load level of 0% may indicate that the filter has not collected dust, for example, because it has been completely cleaned or newly replaced. Typically, during use of the device 200, the filter load level may steadily increase as air flows through the device and dirt is filtered out of the air.

[0076] The manufacturing tolerances of the air moving device 200 can account for the variability of operation between different devices. For example, during the calibration process after the device is assembled, various operating parameters of the device can be measured. The manufacturing tolerance of a particular device can be expressed as a percentage of the total allowable tolerance. In one example, at the end of a device production line, an orifice plate with an orifice of a given diameter is connected to the inlet of the device, where it is known that the device has a clean filter, i.e., a filter load value of 0%. Ambient temperature and pressure are measured. The device is operated at a given power level, and operating parameters, such as δ-P, are measured. Where the input power, ambient temperature, ambient pressure, filter load value are measured or otherwise known, the measured δ-P represents a manufacturing tolerance factor. This process can be repeated at multiple power levels and different orifice diameters.

[0077] In some examples, the first predetermined relationship may define a multi-dimensional lookup table that maps an operating parameter value and one or more other parameter values ​​to an inlet limit value. In one example, the first predetermined relationship defines a six-dimensional lookup table that maps manufacturing tolerances, ambient pressure, ambient temperature, motor input power, filter load, and corresponding values ​​of an operating parameter, such as operating pressure, to an inlet limit value.

[0078] In another example, a lower dimensional lookup table can be used, in which the normalized value of the operating parameter is mapped to the inlet limit value. The normalized value of the operating parameter can be obtained by normalizing the operating parameter value relative to one or more other parameters, such as those mentioned above. For example, a five-dimensional lookup table can be defined, which maps the corresponding values ​​of manufacturing tolerances, ambient pressure, ambient temperature, motor input power, and operating pressure values ​​to the normalized value of the operating pressure. Then, another two-dimensional lookup table can be used to obtain the inlet limit value from the normalized value of the operating pressure and the filter load value. In this example, the lower dimensionality of the lookup table means that the calculation is simpler. However, the accuracy of the determined inlet limit value is highly dependent on the accuracy of the normalization process. On the contrary, using a higher dimensional lookup table without performing a normalization process means that the calculation may be more expensive in calculation, but the accuracy of the output does not depend on the accuracy of any normalization process.

[0079] In another example, the first predetermined relationship can be represented using multidimensional curve fitting or an artificial neural network. In some examples, such a representation can be more efficient than a lookup table in terms of the amount of memory required.

[0080] Figure 4 An example of a first predetermined relationship relating a normalized value of operating pressure to an inlet restriction value is shown. This example is a motor of a vacuum cleaner.

[0081] exist Figure 4In the example of , the operating pressure shown on the y-axis is a δ-P value, which defines the difference between the motor ambient pressure before start-up and the pressure at the motor inlet during operation. The unit of δ-P is kilopascals. The inlet restriction value refers to the orifice plate diameter in millimeters. A first curve 402 maps normalized δ-P values ​​to inlet restriction values, the curve being obtained by a suitable calibration process, which involves operating the vacuum cleaner under known conditions, wherein the inlet restriction is provided by orifices of different diameters. The orifice diameter and the corresponding values ​​of δ-P have been measured. The first curve 402 is obtained by normalizing the values ​​of δ-P relative to the values ​​of manufacturing tolerances, ambient pressure, ambient temperature and motor input power. The first curve 402 uniquely maps normalized values ​​of operating pressure to inlet restriction values. However, as will be seen in reference Figure 5 As described, the normalized value of the operating pressure does not take into account the filter load value of the motor. Therefore, different values ​​of the filter load will result in different mappings between the normalized operating pressure value and the inlet restriction value.

[0082] Figure 5 A set of curves 402, 504, 506 are shown which relate normalized values ​​of operating pressure to inlet restriction values. Each curve corresponds to a different filter loading value. Figure 4 The first curve 402 is also Figure 5 , and corresponds to a filter load value of 0%. A second curve 504 corresponds to a filter load value of 50%. A third curve 506 corresponds to a filter load value of 100%. To determine an inlet restriction value, a set of curves 402, 504, 506 is used, and one of the curves 402, 504, 506 can be selected based on a given value of filter load. Then, for a known filter load value, a normalized value of the operating pressure uniquely determines the inlet restriction value. In some examples, method 300 includes determining a filter load value. An example of a method for determining a filter load value is described in detail below.

[0083] Back to Figure 3 At block 306, method 300 includes controlling the input power of the motor based on the determined value of the inlet restriction. Controlling may include adjusting the motor input power according to a set curve that relates motor input power values ​​to inlet restriction values. For example, a set curve may be defined that maps the determined value of the inlet restriction to input power values. The set curve may be used to determine a desired input power from the determined value of the inlet restriction. The input power of the motor may then be adjusted to the determined desired input power.

[0084] In some examples, the set curve includes a plurality of discrete power levels, each power level corresponding to a range of inlet limit values. The number of discrete power levels can be, for example, two, three, or more. In other examples, the set curve can be a continuous curve. For example, the power curve can include a curve that associates a range of inlet limit values ​​with input power values.

[0085] An example of such a curve is Fig. 6A -C. Fig. 6A -C, the motor input power value is shown on the y-axis. The inlet limit value is on the x-axis and is plotted against Figure 4 and Figure 5 is defined in the same way according to the orifice diameter.

[0086] Fig. 6A A first example power curve is shown in Fig. 6A , the set curve includes two discrete power levels: a first power level 602 and a second power level 604. The first power level 602 corresponds to a higher first power P1, and the second power level 604 corresponds to a lower second power level P2. A low value range of the orifice diameter is mapped to the first power level 602, while a higher value of the orifice diameter is mapped to the second power level 604. Therefore, when the inlet restriction of the air moving device is highly restricted, that is, when the value of the orifice diameter is low, the method determines that the first higher input power P1 should be used. This allows the suction of the device to be increased when the airflow entering the device is highly restricted. When the inlet restriction level is low, that is, when the orifice diameter value is high, the method determines that the second lower input power P2 should be used. When feasible, using a lower power at a lower restriction level can allow the device to operate with lower power consumption while still providing sufficient suction power. This can allow the device 200 to use less energy and, for example, allow a battery-powered device to operate for a longer time before the battery is exhausted.

[0087] The power curve may also define transition points between different power levels. The transition points may be different depending on whether the transition is from a lower to a higher power level or from a higher to a lower power level. For example, an "upward" transition from a lower level to a higher level may occur at a smaller aperture diameter than a "downward" transition from a higher level to a lower level. This may help prevent power level transitions between power levels from being more frequent than desired, such as when the determined aperture diameter values ​​have small changes near the boundaries between power levels.

[0088] Fig. 6A An example of such a transition point is shown represented by dashed arrows 606a, 606b. Fig. 6AIt can be seen that the first transition 606a from the lower power level 604 to the higher power level 602 occurs at a lower value of the aperture diameter than the second transition 606b from the higher power level 602 to the lower power level 604 .

[0089] Figure 6B A second example power curve is shown. Fig. 6A Compared to the two discrete power levels of the first example power curve, the second example power curve includes three discrete power levels 608, 610, 612. Fig. 6A , different transition points represented by dashed arrows are defined between power levels 608, 610, 612, depending on whether the transition is an "up" transition or a "down" transition.

[0090] Figure 6C A third example power curve is shown. Figure 6C The power curve of is continuous. That is, there are no transition points between discrete power levels where the power level is discontinuous for varying orifice diameters. Figure 6C The power curve of includes a first portion 614 corresponding to a small orifice diameter and a second portion 616 corresponding to a large orifice diameter. The first portion 614 in this example is flat and maps a range of orifice diameter values ​​to a single high power value. The second portion 616 defines a curve that maps increasing orifice diameter values ​​to decreasing power values.

[0091] It will be appreciated that various other types of mappings of inlet limits to input powers may be used. For example, the power curve may include one or more continuous portions in which the power level varies smoothly for varying orifice diameters and / or one or more discontinuous portions in which a change in orifice diameter corresponds to a transition between one discrete power level and another discrete power level.

[0092] Method 300 can be performed multiple times during operation of the air moving device. For example, the input power to the motor can be continuously controlled based on a determined level of inlet restriction. For example, the inlet restriction value can be determined at regular intervals according to the above steps, and the value of the input power can be controlled accordingly. In this way, the input power can, for example, be continuously adjusted to be suitable for the inlet restriction level at which the device is operating. The input power can accordingly be constantly adjusted to a level suitable for the task performed by the air moving device.

[0093] As described above, determining an inlet restriction value based on operating parameters of the motor can allow for reliable and accurate determination of the inlet restriction based on observable physical parameters without directly measuring the inlet restriction. The method can also allow for determination of the inlet restriction for controlling input power without requiring additional sensors or processing to directly measure the inlet restriction.

[0094] Figure 7 A flowchart representation of an example method 700 for determining a filter load value for an air moving device 200 is shown. In some examples, the method 700 is performed to determine a filter load value for use in a method for determining motor input power. For example, the example method 700 may be performed as Figure 3 3. The example method 300 is performed as a portion of the example method 300.

[0095] The method 700 includes performing a measurement process at block 702, the measurement process including determining a first value of a second operating parameter of an air moving device, the first value being a value of the second operating parameter when the air moving device is operating with a first inlet restriction.

[0096] The second operating parameter can be an operating pressure of a motor of the air moving device 200. For example, the operating pressure can be a delta-P or any other type of operating pressure described above. For example, the operating pressure can be a normalized value of the operating pressure, such as a normalized delta-P value. In some examples, the operating pressure can be the same operating pressure used in the method 300 of determining the motor input power value. This can be effective because only one type of operating parameter is needed to determine the filter load and the input power. In other examples, a different type of operating pressure can be used to determine the filter load value compared to the type of operating pressure used in the method of determining the motor input power.

[0097] In some examples, the operating parameter may be the speed of a motor of the air moving device 200. The speed may be measured, for example, by a suitable sensor (not shown). In other examples, the operating parameter may be the airflow velocity. In some examples, the airflow velocity may be determined based on a pressure operating pressure measurement, as will be described below according to examples.

[0098] The first inlet restriction condition may indicate a minimum level of inlet restriction of the air moving device 200. For example, the first value of the second operating parameter may be a second operating parameter value measured when the air moving device 200 is operated at a minimum level of inlet restriction, or equivalently, at a maximum equivalent orifice diameter. The minimum level of inlet restriction may correspond to the device 200 operating in free air. That is, the minimum level of inlet restriction may be a level of inlet restriction acting on the device 200 when the tool of the vacuum cleaner is not engaged with a surface, such that there is no external obstruction to the flow of air into the device 200.

[0099] In other examples, the first inlet limit condition may be a known property of the inlet limit value distribution of the device 200. For example, an average or mode inlet limit value may be determined for the device 200 over a period of operation. The first value of the second operating parameter may be a value measured when the device 200 is operating at the average or mode inlet limit value.

[0100] The method 700 also includes, at block 704, performing a determination process to determine a filter loading value for a filter of the air moving device 200. The determination process includes determining a relationship between the second operating parameter value and the filter loading value when the air moving device 200 is operating at the first inlet restriction condition based on the first value of the second operating parameter and the first predetermined relationship.

[0101] Now refer to Figure 8 An example of a determination process for determining a filter load value is described. Figure 8 The above reference Figure 5 A set of normalized delta-P curves 402, 504, 506 are depicted. Figure 8 A first probability distribution 802 of applicable inlet restriction values ​​for a vacuum cleaner is shown. The first probability distribution 802 represents the probability of the vacuum cleaner having a given level of inlet restriction when operating with a first tool attached, based on the equivalent orifice diameter. The first probability distribution 802 corresponds to a passive tool including a relatively wide nozzle and a selectively engageable brush. Figure 8 It can be seen that in this example, the inlet restriction values ​​of the first probability distribution 802 range from about 13 mm to about 47 mm. The minimum level of inlet restriction in the first probability distribution 802 corresponds to an orifice diameter of about 47 mm.

[0102] Figure 8 Also shown are respective projections of the first probability distribution 802 onto the two normalized delta-P curves 402, 506. The first projection 804 is the projection of the first probability distribution 802 onto the first curve 402, which, as described above, corresponds to a filter loading of 0%. The second projection 804 is the projection of the first probability distribution 802 onto the third curve 506, which, as described above, corresponds to a filter loading of 100%.

[0103] Projections 804, 806 define corresponding probability distributions of measured normalized values ​​of δ-P for filter load values ​​of 0% and 100%, respectively. In other words, the first projection 804 defines the probability of measuring a given normalized value of δ-P when the device is operated at a filter load of 0%. Similarly, the second projection 806 defines the probability of measuring a given normalized value of δ-P when the device is operated at a filter load of 100%. Figure 8Other projections not shown in can be defined, defining the probability distribution of normalized δ-P at different filter load values ​​(eg, 25%, 50%, 75%, etc.).

[0104] In general, the values ​​of normalized delta-P defined by curves 402, 504, 506 decrease rapidly for small values ​​of orifice diameter, but begin to level off for large values ​​of orifice diameter. This leveling off means that a given normalized delta-P value can be uniquely mapped to a given one of the curves 402, 504, 506 at high values ​​of orifice diameter. In an example, this property can be used to determine the level of filter loading from a measurement of normalized delta-P.

[0105] For example, according to the first probability distribution 802, the minimum normalized delta-P value in the known probability distributions 804, 806 corresponds to a device operating at a known maximum orifice diameter, which in this example is approximately 47 mm. To determine the filter loading value, the minimum value of the normalized delta-P during operation of the vacuum cleaner can be measured and mapped to a given one of the curves 402, 504, 506 at the known maximum orifice diameter. By determining which of the curves 402, 504, 506 the measured normalized delta-P value maps to, the filter loading value can be determined.

[0106] For example, in Figure 8 , the third curve 506 and probability distribution 806 show that for a filter loading value of 100%, the minimum value of the normalized delta-P corresponding to a maximum orifice diameter value of approximately 47 mm is approximately 15.3 kPa. Therefore, if the minimum normalized value of delta-P for the vacuum cleaner is measured to be approximately 15.3 kPa, this indicates that the filter loading is 100%. Similarly, the first curve 402 and probability distribution 804 show that for a filter loading value of 0%, the minimum normalized delta-P value also corresponding to a maximum orifice diameter value of approximately 47 mm is approximately 11.2 kPa. Therefore, the measurement of a minimum normalized delta-P value of approximately 11.2 kPa indicates a filter loading value of 0%.

[0107] Fig. 9 Another example of a method of determining a filter loading value is shown. Fig. 9 Similar to Figure 8 , but relates to a vacuum cleaner operated with a second tool attached. Fig. 9 A second probability distribution 902 of inlet restriction values ​​applicable when the vacuum cleaner is used with a second tool is shown. Figure 8 As described, Fig. 9 The projections 904, 906 of the second probability distribution 902 on the first curve 402 and the third curve 506 are shown. Figure 8As described, the filter loading value can be determined by measuring the minimum normalized delta-P value of the vacuum cleaner in use. It can then be determined which of a plurality of curves, such as curves 402, 504, 506, the minimum value is mapped to. The curve to which the minimum normalized delta-P value is mapped represents the filter loading value.

[0108] As can be seen from a comparison of the second probability distribution 902 and the first probability distribution 802, the second tool generally provides a higher level of inlet restriction than the first tool. For example, the second tool can be a passive slit tool. In this example, the minimum level of inlet restriction provided by the second tool corresponds to an orifice diameter of approximately 23 mm, compared to a value of approximately 47 mm for the first tool. Therefore, for a given filter loading value, the minimum normalized delta-P value when using the second tool is greater than the minimum normalized delta-P value when using the first tool. For example, when using the second tool, the minimum normalized delta-P value at a filter loading of 100% is approximately 16.5 kPa, while the minimum normalized delta-P value at a filter loading of 0% is approximately 13.2 kPa. Fig. 9 The difference in the minimum normalized delta-P value at 0% filter load when the first tool is used and when the second tool is used is shown by arrows 908. In some examples, this difference in the minimum normalized delta-P value at the same filter load value can be used to determine when a tool attached to the device is replaced.

[0109] Fig.10 The filter loading value on the y-axis and the minimum normalized delta-P value on the x-axis are shown. Fig.10 A first filter loading curve 1002 corresponding to a first tool and a second filter loading curve 1004 corresponding to a second tool are shown. Fig.10 It is shown how the minimum normalized value of delta-P maps to a given filter loading value for the first tool and the second tool. Fig.10The difference 908 between the minimum normalized delta-P values ​​of the first tool and the second tool at a filter load value of 0% is shown. As described above, during use of the device, the typical filter load value changes gradually as the filter collects more dirt. Therefore, unless the operating conditions of the device change, a sudden, relatively large change in the determined value of the filter load is generally not expected. If such a sudden change is detected, then in some examples, such a change can be used to indicate a change in the operating conditions of the device. For example, a sudden change in the determined value of the minimum normalized delta-P detected can be considered an indication of a change in the tool attached to the vacuum cleaner. For example, if the measured minimum normalized delta-P value changes by a difference 908 within a relatively short period of time of use of the device, this can be considered to indicate that the vacuum cleaner has transitioned from an operating state in which the first tool is attached to an operating state in which the second tool is attached. In addition, the correct filter load curve for associating the minimum normalized delta-P value with the filter load value can be determined based on the type of tool attached to the device, for example, if it is known which type of tool is attached to the device. For example, upon detecting a change 908 in the determined minimum normalized delta-P value, the device may move from using the first filter load curve 1002 to determine the filter load value to using the second filter load curve 1004 to determine the filter load value.

[0110] Fig.11A and 11B Examples of probability distributions 1102 , 1104 of normalized delta-P values ​​when the apparatus 200 is used with a given tool (eg, a first tool) are shown. Fig.11A Corresponds to a vacuum cleaner with a filter loading value of 0%. Fig. 11BCorresponding to a vacuum cleaner operating at a filter load value of 100%. In an example, in order to determine such a probability distribution, a fixed number of counters are defined, for example, 100 counters may be defined. Two one-dimensional arrays are defined, a pressure bin array and a FIFO first-in first-out array. The length of the FIFO array is equal to the fixed number of counters. The delta-P values ​​are measured and normalized. Corresponding to the measured and normalized values, counters are added to the pressure bins. Once all counters are assigned to bins, at the next measurement of normalized delta-P, the earliest assigned counter, which may be the counter in the final position of the FIFO array, is moved to the bin corresponding to the most recently measured normalized delta-P value. In this way, a permanent rolling distribution may be maintained. The rolling distribution may be queried at any time and at any frequency. In an example where the minimum value of the normalized delta-P is the value determined and used to indicate the filter load value, the lowest filled bin is determined in order to determine the minimum value of the normalized delta-P. In some examples, a minimum counter threshold may be set below which the counters in the bin are not counted, so that the lowest filled bin is the lowest bin with at least a threshold number of counters. This may act as a noise filter. In some examples, the distribution may be filtered, for example by determining an exponential moving average, to further remove noise. In other examples, no FIFO array may be defined, and, for example, once all counters have been allocated, the counters may be removed from the pressure bin and allocation of counters may begin again.

[0111] As an example, Fig.11A and 11B The minimum normalized delta-P value 1106 of the distributions 1102, 1104 is shown, representing filter loading values ​​of 0% and 100%, respectively. Fig.11A and 11B Also shown by way of example is a threshold counter value 1108 below which the counter is not counted for purposes of determining the lowest filled bin.

[0112] The above examples have been described with reference to two particular tools. However, it should be understood that a variety of different types of tools may be used with the device 200, and each of these different tools may have an associated probability distribution of inlet limit values ​​that may be used in the method of determining filter load values ​​for the device 200. Furthermore, the inlet limit probability distribution for a given tool may vary depending on the application. However, assuming that a given property of the probability distribution, such as the minimum level of the inlet limit, does not change, the given property may be used to determine the filter load regardless of other changes in the overall probability distribution.

[0113] Although in some of the above examples, the minimum value of the second operating parameter is the value used to indicate the filter load level value, in other examples, other values ​​of the second operating parameter can be used to indicate the filter load value. For example, a different property other than the minimum value of the probability distribution of the second operating parameter, such as an arithmetic mean, a mode, or other properties, can be determined and used as the second operating parameter value indicating the filter load value.

[0114] The examples of the above methods may allow the filter load value to be determined based on the correspondence between the filter load value and the operating parameters of the motor. In some examples, this may allow the filter load value to be determined without using additional additional sensors (e.g., pressure sensors upstream and downstream of the filter).

[0115] The filter load value can be used for various purposes. For example, as described above, in some examples, determining the inlet limit value may require revising the filter load value. In another example, the filter load value can be used to provide an alarm. For example, when the filter load value reaches a given threshold, an alarm can be issued indicating that the filter should be cleaned or replaced.

[0116] Method 700 may also be performed multiple times during operation of the air moving device, for example, at regular intervals. For example, the filter load value may be determined at regular intervals that are the same operating parameter used to control the motor input power. As described above, in some examples, this may be the same operating parameter as the second operating parameter, for example, both may be delta-P.

[0117] Fig.12 Another exemplary schematic diagram of a motor assembly 1200 is shown. The motor assembly 1200 includes the same Figure 1 For features corresponding to those of the motor assembly 100 described above, such features are labeled with the same reference numerals where labeled. For clarity, Fig.12 The pre-motor filter is not shown.

[0118] The motor assembly 1200 also includes a second pressure sensor 1220 and wires 1222 that electrically connect the second pressure sensor 1220 to the circuit board 1214. The motor assembly 1200 also includes an inlet tube 1226 that provides a fluid connection from the second pressure sensor 1220 through the housing 1224 to the inlet 1230 of the impeller 1208. This allows the second pressure sensor 1220 to measure the pressure at the impeller inlet 1230. Fig.12 As can be seen from the schematic diagram, the cross-sectional area of ​​the motor is narrower at the impeller inlet 1230 than at the motor inlet 1210.

[0119] Fig.13 Another example motor assembly 1300 is shown. Fig.13 In the motor assembly 1300, the second pressure sensor 1320 is located outside the circuit board 1314, and the motor assembly 1300 is Fig.12 The motor assembly 1200 of FIG. 1300 is the same as that of FIG. 1300. A passage or conduit 1322 provides a fluid connection between the second pressure sensor 1320 and the impeller inlet 1330. The passage 1322 allows the second pressure sensor 1320 to measure the pressure at the impeller inlet 1330 without requiring the second pressure sensor to be located at the impeller inlet 1330.

[0120] Such a passage can be provided in a variety of ways. In one example, the passage 1326 can be formed by a tube. The tube can, for example, extend along the outer surface of the housing 1324 and extend through a hole 1326 in the housing to provide a fluid connection from the second pressure sensor 1320 to the impeller inlet 1330. At one end of the passage 1326 where the second pressure sensor 1320 is located, an airtight seal can be formed around the second pressure sensor 1320. The seal can, for example, include a circular, for example, EPDM foam seal that seals the tube to the location on the circuit board 1314 where the second pressure sensor 1320 is located. Fig.12 A similar seal is formed around the second pressure sensor 1220 of the motor assembly 1200.

[0121] In another example, the passageway may be integral to the housing of the motor assembly. Fig.14 An exemplary schematic diagram of such a housing 1424 is shown, wherein the channel 1422 extends through the housing 1424. In such an example, the housing 1424 can be formed by an injection molding process, and the channel through the housing 1424 is formed during the injection molding, for example, by using removable pins 1430a, 1430b during the injection molding. In use, with reference to Fig.13 In the manner described, a hole 1426 through the housing 1424 leads to the impeller inlet of the motor. In use, the second pressure sensor is located at the upstream end 1428 of the passage 1422. This provides a fluid connection to the second pressure sensor via the passage 1422 and allows the second pressure to be configured to measure the pressure at the impeller inlet. This can allow the second pressure sensor to be conveniently positioned. The second pressure sensor can be located, for example, on a circuit board of the device. In addition, forming the passage 1422 integrally with the housing 1424 can be cost-effective and convenient.

[0122] In another example, the channel may be formed between an outer surface of the housing and a base positioned against the outer surface of the housing. Fig.15 Such an example is schematically illustrated. Fig.15In the embodiment, a base 1532, for example made of rubber, has a groove 1534 therein. The base 1532 seals in an airtight manner against the outer surface of a housing 1524, which has a hole 1526 which, in use, leads to the impeller inlet. The passage 1522 is created by the gap provided by the groove 1534 in the base 1532 between the base 1532 and the outer surface of the housing 1524. Fig.14 and Fig.15 In both examples, in use, the second pressure sensor is hermetically sealed to the channels 1422, 1522 at the upstream ends 1428, 1528 of the channels 1422, 1522. For example, in Fig.15 In the example of FIG. 1 , base 1532 may be a rubber base that forms a seal around the second pressure sensor.

[0123] In each example motor assembly 1200, 1300, a first pressure sensor 1218, 1318 is positioned to take pressure measurements at the air inlet 1210, 1310. The pressure measurements taken by the first pressure sensor 1218, 1318 include the ambient pressure p measured before the motor is started. a In addition, the pressure measurements performed by the first pressure sensors 1218, 1318 include measurements of the first pressure p1 performed during motor operation. The temperature sensors 1216, 1316 are configured to measure the ambient temperature T a The second pressure sensor 1220, 1320 is configured to measure the second pressure p2 at the impeller inlet 1230, 1330 during motor operation. The ambient pressure p a , the first pressure p1 and the second pressure p2 are each an absolute pressure.

[0124] In an example, measurements taken by the first pressure sensor 1218, 1318, the second pressure sensor 1220, 1320, and the temperature sensor 1216, 1316 are used to determine a dynamic pressure value. In one example, the dynamic pressure measurement is determined as follows.

[0125] By subtracting the ambient pressure p from the first pressure p1 a To determine the static pressure p in the motor static The first pressure p1 is usually lower than the ambient pressure p a , because the operation of the motor causes a partial vacuum to be created within the motor housing 1324.

[0126] Determine the total pressure p at the impeller inlet by subtracting the second pressure p2 from the first pressure p1 total The total pressure at the impeller inlet is p total From the static pressure p static and dynamic pressure p dynDue to the lower cross-sectional area and the associated higher air velocity at the impeller inlet 1230 , 1330 compared to the motor inlet 1210 , 1310 , the second pressure p2 is generally lower than the first pressure p1 .

[0127] Dynamic pressure p at the impeller inlet 1230, 1330 dyn The total pressure p at the impeller inlet 1230, 1330 total Subtract the static pressure p in the motor from static The dynamic pressure p dyn May also be called air velocity pressure.

[0128] The dynamic pressure p dyn , first pressure p1 and temperature T a Input into the density ratio formula to determine the STP p dyn@STP The dynamic pressure value at p dyn@STP The value of is the dynamic pressure value corrected for standard temperature and pressure. The dynamic pressure value is therefore normalized for the ambient conditions in which the motor is operating. This allows, for example, the definition of a single lookup curve that relates the dynamic pressure value to the airflow velocity or other parameter. The applicable density ratio for a given motor depends on the type of motor. For example, the following density ratio formulas (1) to (3) apply to constant power motors, AC series motors, and constant speed motors, respectively:

[0129]

[0130] Among them, p dyn@STP , p1 and p dyn In kPa, T a In degrees Celsius, 101.325 is the standard pressure in kPa, 293 is the standard temperature in Kelvin, and 273.15 is 0 degrees Celsius in Kelvin.

[0131] The determined dynamic pressure value can be mapped to various parameters. For example, in the example of the above method, the dynamic pressure value can be used as an operating pressure. For example, the dynamic pressure value can be mapped to an inlet restriction and / or a filter load value, for example in a manner similar to that described above for the δ-P value. Additionally or alternatively, the dynamic pressure value can be mapped to an airflow velocity value through the motor. The airflow velocity can be used as an operating parameter in the above example method. The mapping of the dynamic pressure value to the airflow velocity can be determined, for example, by a calibration process. In such a calibration process, an air moving device can be operated with an airflow velocity measuring device, which can include a bell mouth, a venturi tube, or an orifice plate for measuring the airflow velocity through the device, while performing a measurement that allows the determination of a dynamic pressure value corresponding to the airflow measurement. Therefore, when the device is operated after calibration, a dynamic pressure value can be determined and mapped to an airflow velocity value in order to determine the airflow velocity through the device in use.

[0132] The above embodiments should be understood as illustrative examples of the present invention. Other embodiments are contemplated. It should be understood that any feature described with respect to any one embodiment may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiment. In addition, equivalents and modifications not described above may also be employed without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method for controlling input power of a motor of an air moving device, the method comprising: performing a measurement process to determine a first value of an operating parameter of the motor, wherein the operating parameter is an operating pressure of the motor or an air flow rate through the motor; performing a determination process to determine an inlet restriction value of the air moving device based on a first value of an operating parameter of the motor and a first predetermined relationship between the value of the operating parameter of the motor and an inlet restriction value of the air moving device; and Input power to the motor is controlled based on the determined inlet limit value.

2. The method of claim 1 , wherein the operating parameter is an operating pressure, and the measuring process comprises determining a first value of the operating parameter of the motor based on: Ambient pressure measurements; and Motor inlet pressure measurement during operation of the motor. 3 . The method of claim 2 , wherein the ambient pressure measurement and the motor inlet pressure measurement are measured by a single pressure sensor at different times.

4. The method of claim 1 , wherein the measuring process comprises determining a first value of an operating parameter of the motor based on: a first pressure measurement of a pressure at a first location in a motor assembly in which the motor is located; and a second pressure measurement of the pressure at a second location in the motor assembly; The second position is downstream of the first position.

5. The method of any one of the preceding claims, wherein the first predetermined relationship relates an operating parameter value of the motor and one or more other parameter values ​​to an inlet restriction value of the air moving device, and wherein the determining process comprises: The inlet limit value is determined based on one or more corresponding other parameter values ​​of the one or more parameters.

6. The method of claim 5, wherein the one or more other parameters include one or more of the following: Environmental pressures; Ambient temperature; Motor input power; and Manufacturing tolerances of the air moving device.

7. The method according to claim 5 or 6, wherein the determining process comprises: determining a first normalized value of the operating parameter by normalizing the first value of the operating parameter using one or more corresponding values ​​of one or more other parameters; and An inlet restriction value for the air moving device is determined based on the normalized operating parameter.

8. The method of any one of claims 5 to 7, wherein the one or more other parameters include a filter loading value of a filter of the air moving device.

9. The method of claim 8, wherein the determining process includes determining the filter loading value.

10. The method of claim 9, wherein determining the filter load value comprises: performing a second measurement process including determining a first value of a second operating parameter of the air moving device, the first value being a value of the second operating parameter when the air moving device is operating at a first inlet restriction; and A second determination process is performed to determine the filter loading value, the determination process including determining the filter loading value based on a first value of the second operating parameter and a second predetermined relationship, wherein the second predetermined relationship relates the second operating parameter value to the filter loading value for the air moving device when operating under the first inlet restriction condition.

11. The method of claim 10, wherein the second operating parameter is: an operating pressure of a motor of the air moving device; The speed of the motor of the air moving device; or The air flow rate through the motor of the air moving device.

12. The method of claim 10 or 11, wherein determining the first value of the second operating parameter comprises: determining a plurality of values ​​for the second operating parameter; determining a distribution of a plurality of values ​​of the second operating parameter; determining a first property of the distribution; and Based on a first property of the distribution, a first value of the second operating parameter is determined. The method of claim 12 , wherein the first property of the distribution is a minimum value in the distribution.

14. A method according to any one of the preceding claims, wherein the controlling comprises regulating the motor input power according to a set curve relating motor input power values ​​to inlet limit values. The method according to claim 14 , wherein the set curve is a continuous curve.

16. The method of claim 14, wherein the set profile includes a plurality of discrete power levels, each power level corresponding to a respective range of inlet limit values.

17. The method according to any of the preceding claims, comprising performing the measuring process, the determining process and the controlling a plurality of times during operation of the air moving device.

18. A set of machine readable instructions which, when executed by a processor of an air moving device, cause the air moving device to perform the method of any one of claims 1 to 17.

19. An air moving device, comprising: processor; and A memory comprising a set of machine-readable instructions, which, when executed by a processor, cause the processor to perform a method according to any one of claims 1 to 17.

20. The air moving device of claim 19, wherein the air moving device is a vacuum cleaner.

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