Devices for particle detection and evaluation
The device converts analog signals to digital for flexible particle detection in vacuum cleaners, addressing interference and cost issues, enabling adaptable and accurate particle evaluation across different models.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KURZ ELEKTRONIK GMBH
- Filing Date
- 2024-03-21
- Publication Date
- 2026-05-29
Smart Images
Figure 2026517342000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a device for detecting and evaluating particles in the suction flow of an electric vacuum cleaner, comprising a light source designed to emit a light beam passing through a measurement space along an optical path, in particular an infrared LED, and a light sensor designed to receive the light beam after it has passed through the measurement space, the light sensor emitting an analog measurement signal. Furthermore, the present invention relates to a method for detecting and evaluating particles. Finally, the present invention relates to an electric vacuum cleaner comprising such a device.
Background Art
[0002] In the past, the applicant has used various dust sensors in electric vacuum cleaners to detect the amount of particles in the suction flow and display it to the user. In so doing, in principle, an analog evaluation circuit that directly controls an LED has been used. Optically acting dust sensors are known, for example, from Patent Document 1.
[0003] In addition to optically functioning dust sensors, sensors that use piezoelectric components for dust detection are also commercially available. Patent Document 2 discloses such a dust sensor and an evaluation circuit for evaluating the measurement signal. One of the drawbacks of these dust sensors is that being placed in the suction flow is considered to interfere with the suction flow. Also, for example, the sucked-in particles may be trapped by the dust sensor, further obstructing the suction flow. Finally, the measurement results of these dust sensors are not independent of the suction force, and tend to deteriorate when the suction force is small. This is inconvenient, for example, in the case of use in so-called robotic vacuum cleaners. This is because they operate with a small battery and thus have to operate with a small suction force.
[0004] Although conventional solutions actually perform well in some application areas, they lack flexibility with respect to a more extensive and comprehensive use area. Also, they are expensive and difficult to integrate into the latest digital systems.
Prior Art Documents
[0005] [Patent Document 1] German Patent No. 3803824 [Patent Document 2] German Patent Application Publication No. 102009005598 Specification [Overview of the project] [Problems that the invention aims to solve]
[0006] Against this backdrop, the objective of the present invention is to further develop such devices so that they are economical to manufacture and can be flexibly adapted to various application areas.
[0007] This objective is achieved by the device specified in claim 1, particularly for the detection and evaluation of particles in the suction stream of a vacuum cleaner. [Means for solving the problem]
[0008] The present invention provides a frequency evaluation device comprising: an analog-to-digital converter designed to convert an analog measurement signal into a time-discrete digital measurement; a buffer memory designed to buffer a predetermined number of measurement values; a frequency evaluation device connected to the buffer memory, which is a frequency converter designed to decompose a time-discrete measurement from the buffer memory into a predetermined number of n1 frequency spectrum values in a frequency range; a first weighted summing device designed to multiply each of the n1 frequency spectrum values by a first weighting value and add the n1 weighted frequency spectrum values together to obtain a first weighted sum; and a transmitting device designed to provide the digital output value of the frequency evaluation device to a digital output for transmission.
[0009] The device according to the present invention has the advantage of being economical due to its digital design and can be flexibly implemented in various vacuum cleaners. Since the signal is evaluated entirely digitally, the evaluation process can be adapted very easily using freely programmable parameters. The evaluation results are provided in digital format by the transmitting device, so, for example, another control device of the vacuum cleaner can acquire the results and use them for other control purposes.
[0010] Furthermore, by evaluating various frequency ranges, particle size can be assessed, and weighting allows for adaptation to the application area.
[0011] The goal is thus fully achieved.
[0012] In another preferred development, the frequency converter has a unit for executing the Gerzel algorithm.
[0013] One advantage of this algorithm is that it requires less computational power than, for example, the FFT (Fast Fourier Transform) method.
[0014] In a preferred evolutionary form, the n1 first weighting values are adjustable.
[0015] This has the advantage of improving flexibility and adaptability.
[0016] In one preferred evolutionary form, a first low-pass filter is provided to which a first weighted sum is supplied.
[0017] This approach has the advantage of enabling a certain degree of smoothing and, consequently, improvement of evaluation results.
[0018] In one preferred evolutionary form, the device is an amplitude evaluation device connected to a buffer memory on the input side, comprising: a difference unit that determines the maximum and minimum values of the values stored in the buffer memory and generates a difference value therefrom; a first filter array including n2 low-pass filters arranged in parallel with different time constants and each supplied with a difference value; and a second weighted summation device designed to receive individual values from the n2 low-pass filters, multiply each filtered value by a second weighting value, and sum the weighting values to form a total difference value.
[0019] The amplitude evaluation device leads to further improvements in evaluation results. By evaluating the amplitude value, changes in particle size can be detected and represented dynamically. Furthermore, processing through multiple parallel low-pass filters makes it possible to temporally classify these changes, that is, to identify the period during which the changes occur.
[0020] In one preferred evolutionary form, the time constant of the low-pass filter in the first filter array can be changed by a power of 2.
[0021] This strategy has proven to be particularly advantageous.
[0022] In a preferred alternative development, the n2 second weighting values can be adjusted.
[0023] This approach improves the flexibility of the device, i.e., its adaptability to various application areas.
[0024] In a preferred development form, it is an integration evaluation device connected to a buffer memory on the input side, including a total unit that generates an integrated value as the sum of the absolute values of the differences between the values in the buffer memory and the average value of all the values in the buffer memory, a second filter array including n3 low-pass filters arranged in parallel with different time constants and each supplied with an integrated value, and a third weighting total device designed to receive individual values from the n3 low-pass filters of the second filter array, multiply each received value by a third weighting value, and sum the weighting values to form a total integrated value. An integration evaluation device is provided.
[0025] This approach has the advantage of providing more options for evaluation. The integration evaluation device enables the temporal detection of changes in the amount of particles. This makes it possible to determine whether the degree of cleaning of the surface being vacuumed is improving or stagnating.
[0026] These approaches have been found to be particularly advantageous.
[0027] In a preferred development form, the time constants of the low-pass filters in the second filter array change as powers of 2. Furthermore, the n3 third weighting values are preferably adjustable.
[0028] In a preferred development form, a fourth weighting total device is provided, which is designed to receive values from a frequency evaluation device, an amplitude evaluation device, and an integration evaluation device, multiply each supplied value by a fourth weighting value, and sum the weighting values to form a total output value.
[0029] This approach allows for further adaptability of the evaluation. At the output, different weightings can be applied to different evaluations.
[0030] In one preferred evolutionary configuration, a first operational amplifier and a second operational amplifier are provided, the first operational amplifier controlling the light source, and the second operational amplifier connected to a light sensor on its input side and outputting an analog measurement signal on its output side. The signal from the light sensor is supplied to the first operational amplifier, which preferably controls the light source with a control signal based on this signal so that the signal from the light sensor has a predetermined value when the path is not contaminated.
[0031] This approach has the advantage that, by controlling and adjusting the operating point, the measurement results become independent of contamination.
[0032] In one preferred evolutionary configuration, a monitoring unit is provided, designed to monitor the control signal and to indicate when the control signal exceeds a predetermined, particularly pre-defined, value. Preferably, a reporting signal is sent to the transmitting device.
[0033] This approach has the advantage of being able to issue a warning, for example, if the device is unable to properly set its operating point due to excessive contamination.
[0034] The fundamental objective of the present invention can also be achieved by the method specified in claim 19.
[0035] Its advantages correspond to the advantages of the aforementioned devices.
[0036] Finally, the above objective can also be achieved by a cleaning device as defined in claim 22, in particular a vacuum cleaner.
[0037] The device according to the present invention is particularly convenient for use in a robotic vacuum cleaner. The digital output values provided by the device according to the present invention as a result of evaluation can be used by the control system of the suction motor and / or drive unit. For example, it is possible to target a particular surface multiple times based on the degree of cleaning of the vacuumed surface, or to exclude other cleaned surfaces from the area to be moved.
[0038] It is understood that the features described above and those described below can be used not only in the combinations specified in each case, but also in other combinations, or individually, without departing from the scope of the present invention.
[0039] Other advantages and embodiments of the present invention are evident from this specification and the accompanying drawings. [Brief explanation of the drawing]
[0040] [Figure 1] This is a block diagram of a vacuum cleaner including components related to the present invention. [Figure 2] This is a block diagram of a device according to the present invention for detecting and evaluating particles in the suction stream of a vacuum cleaner. [Figure 3] This is a block diagram of a frequency evaluation device. [Figure 4] This is a block diagram of the amplitude evaluation device. [Figure 5] This is a block diagram of the integral evaluation device. [Figure 6] This is a block diagram of a robotic vacuum cleaner including the device according to the present invention. [Modes for carrying out the invention]
[0041] The device for detecting and evaluating particles in a gaseous flow, described in detail below, essentially functions as a dynamic display unit with flexible adjustment capabilities for the quantity and quality of particles present in the gaseous flow. In particular, it detects and displays changes in the quantity and quality of particles over time. This device is used particularly in vacuum cleaners to detect and appropriately display the quality and quantity of dust particles in the inhaled air.
[0042] Figure 1 is a block diagram showing the components of a vacuum cleaner 10 related to the present invention. The vacuum cleaner 10 can be, for example, a handheld vacuum cleaner, a floor vacuum cleaner, or a robotic vacuum cleaner. The vacuum cleaner 10 has a motor 12 that sucks in air from a nozzle (not shown) through a suction tube 14 and discharges it again through an exhaust tube 16. The sucked-in air 18 is a mixture of particles, in particular dust particles 20 and air, which is commonly referred to as a two-phase flow or two-phase mixture. The motor 12 is controlled, for example, by a higher-level control device 26 to adjust the power of the motor 14. This higher-level control device 26 can also handle other open-loop and closed-loop control tasks in the vacuum cleaner.
[0043] In a two-phase flow, dust particles are typically filtered from the mixture, and then the mixture passes through an exhaust pipe 16 to a collection container (not shown) that discharges substantially particle-free air.
[0044] A device 30 is provided, comprising a measuring device 31 and a circuit 32, to detect particles 20 in the two-phase flow 18. The measuring device 31 is assigned to a portion of the suction tube 14 and comprises a light source 34 on one side and a photosensor 36 on the other side, which are aligned with each other so as to create an optical path 39 through which light rays travel between the light source 34 and the photosensor 36. Since this optical path 39 is located within the suction tube 14, this portion of the suction tube functions as a measuring space 38. Preferably, the light source and photosensor are located in the suction tube 14 behind a translucent but dustproof and / or airtight cutout / window. The two-phase mixture flowing through this measuring space 38 changes the amount of light reaching the photosensor 36, which is measurable and evaluable, allowing conclusions to be drawn about the degree of cleanliness of the vacuumed surface or how the degree of cleanliness is currently changing. Since the photosensor is located outside the measuring space, the flow through the sensor is not affected.
[0045] Circuit 32 controls a light source 34, preferably designed as an infrared LED 35, and a light sensor 36, preferably designed as a photodiode 37, and returns a measurement signal for evaluation to circuit 32.
[0046] Subsequently, for optical representation of the evaluation results of the received measurement signal, the evaluation results are transmitted by circuit 32 to output device 33 having a display device 40, for example, an LED 42. However, it should be noted that, in this regard, acoustic reproduction of the results is also possible as an alternative to or addition to the optical display device 40.
[0047] The optical / acoustic output is intended to provide the vacuum cleaner user with information, in particular, about the degree of dirtiness or cleanliness of the vacuumed surface, and / or how the degree of cleanliness changes over time.
[0048] As an alternative or addition to the above, the evaluation results are transmitted to a higher-level control unit 26 of the vacuum cleaner 10, which can, for example, control the power of the motor 12 according to the evaluation results.
[0049] Figure 2 schematically shows the device 30 in block diagram form. Inside, a measuring device 31 including an infrared LED 35 (IR-LED) and a phototransistor 37, and a circuit 32 having an analog circuit section 50 and a digital circuit section 60 in this embodiment can be seen. The digital circuit section 60 can be provided in the controller 61.
[0050] The analog circuit section 50 of circuit 32 includes a first operational amplifier 52 equipped with a low-pass filter for adjusting the infrared LED 35 to a desired operating point. The phototransistor 37 supplies the measurement signal to the first operational amplifier 52 as well as to a second operational amplifier 54 equipped with a high-pass characteristic. The second operational amplifier 54 has a high gain coefficient and provides a useful signal from the phototransistor with high intensity. The measurement signal provided by the second operational amplifier 54 is supplied to an analog-to-digital converter 64, which outputs a digital signal or a second discrete digital value at a sampling rate of, for example, 50,000 samples per second.
[0051] Furthermore, the signal generated by the first operational amplifier 52 is supplied to the infrared LED 35 to determine its brightness, but it is also transmitted to a second analog-to-digital converter 66, which generates a digital signal or a time-discrete digital value at a sampling rate of 5 samples per second.
[0052] The feedback of the measurement signal from the phototransistor 37 to the first operational amplifier 52 helps to adjust the operating point of the infrared LED 35. In other words, the first operational amplifier is designed so that a predetermined light intensity / quantity always reaches the phototransistor 37 (assuming no particles are present in the measurement space when setting the operating point). Since the supplied measurement signal is smoothed through a low-pass filter in the first operational amplifier, short-term fluctuations in the measurement signal do not affect the setting of the operating point.
[0053] This control of the operating point prevents, for example, contamination in the optical path region of a translucent notch in the suction tube from affecting the measurement.
[0054] The digital circuit section 60 includes two analog-to-digital converters 64 and 66, as well as other digital functional elements described below.
[0055] A second analog-to-digital converter 66, to which the control signal for the infrared LED 35 is supplied, supplies a digital signal or digital value to an operating point monitoring device 70, which compares the digital value with a predetermined, in particular, adjustable threshold. If this threshold is reached or exceeded, this indicates, for example, that the area in front of the phototransistor 37 or the infrared LED 35 is dirty. If the predetermined threshold is reached or exceeded, the operating point monitoring device 70 sends a warning signal to a transmitter 72. The transmitter 72 processes the warning signal and supplies it to the control device 26 and / or output device 33 via a digital interface 73. The output device 33 can then visually and / or audibly notify the user of the vacuum cleaner 10, for example, that the measurement space 38 should be cleaned.
[0056] The first analog-to-digital converter 64 supplies a digital measurement signal, i.e., a measurement, to a buffer memory 68, preferably designed as a ring memory. This buffer memory 68 stores time-discrete digital measurement values within a time window of, for example, 0.2 seconds, and contains 10,000 measurement values. That is, a sampling rate of 50,000 samples per second. Because the buffer memory 68 is designed as a ring memory, when a new measurement value supplied by the analog-to-digital converter 64 is stored, the oldest measurement value is dropped from the buffer memory 68. Thus, the time window shifts by one value per sample.
[0057] However, it should be noted that the aforementioned sampling rate and buffer memory size are illustrative values, and different options are possible depending on the application.
[0058] Based on the measurements stored in the buffer memory 68, three different evaluations are performed: frequency evaluation, amplitude evaluation, and integral evaluation. For this purpose, a frequency evaluation device 74, an amplitude evaluation device 76, and an integral evaluation device 78 are provided.
[0059] The results of these evaluations are sent in the form of digital data A1, A2, and A3 to a weighted summer 80, which forms a total value by weighting and summing the corresponding data. The series of total values are sent to a low-pass filter 82, which performs smoothing of the total values with a time constant of, for example, 0.1 seconds, and sends the smoothed value to a transmitter 72. The transmitter processes this value and outputs it to an output device 33 and / or a control device 26 via an interface 73. Naturally, the control device 26 and / or the output device 33 may also read the values independently as needed. The output device 33 may be designed to dynamically visualize the values, for example, and may perform linear interpolation for better representation.
[0060] Figure 3 shows the frequency evaluation device 74 in block diagram form. The frequency evaluation device 74 includes a frequency converter 90 that performs a frequency transformation on a supplied time-discrete digital value to divide it into n frequency ranges. The value n is an integer greater than 0, preferably 16. As a result, n frequency values are provided to the output of the frequency converter 90. The transformation of a series of time-discrete values into frequency ranges is well known from a technical standpoint and will not be discussed in detail separately. In this embodiment, for example, a known fast Fourier transform (FFT) method can be used. Alternatively, the so-called Görzel algorithm can be used, which has the advantage of lower computational load.
[0061] The frequency converter 90 reads the time-discrete values to be converted from the buffer memory 68, but it is preferable to perform the frequency conversion after reading all the values from the memory. This means that, in the case of a 0.2-second time window, the frequency converter 90 reads from the buffer memory 68 every 0.2 seconds. Of course, it is also conceivable to read data from the buffer memory 68 at different time orders.
[0062] The n frequency values calculated for the frequency range 1 to n are supplied to the weighted summing device 92. The value n, i.e., the number of frequency ranges to consider, is preferably in the range of 8 to 20, and more preferably 16. By considering the frequency range, it becomes possible to evaluate the particle size in the two-phase mixture. Fine dust particles appear in the higher frequency range, while larger particles can be identified in the lower frequency range.
[0063] The weighting summer 92 multiplies each supplied frequency value by a weighting coefficient. The n weighting coefficients may be different, but their sum is preferably 1. The weighting coefficients can be supplied to the weighting summer 92 in the form of an application-specific weighting vector 94. It is particularly convenient to make this weighting vector adjustable for the user. The weighting coefficients allow setting the particle size in the two-phase mixture that should be given a larger weight in the visualization. Also, by setting the weighting coefficients individually, the user can display different types of contamination in response to them, for example. For example, it is conceivable to store a variety of predetermined selectable weighting vectors for prioritizing fine dust or coarser particles.
[0064] Subsequently, the n weighted frequency values are summed to form a single value, which is fed to the low-pass filter 96. The low-pass filter 96 provides, at its output, a signal or digital value A2 representing the smoothed form of the weighted sum of the weighted sum device. The low-pass filter 96, so to speak, enables the specification of the measurement inertia.
[0065] Figure 4 shows the amplitude evaluation device 76 in block diagram form. It includes a difference unit 100 designed to read values from buffer memory 68, identify maximum and minimum values from these values, and form a difference. This difference value is then provided to the output of the difference unit 100. Unlike the frequency converter 90, the difference value is calculated for each new time window (a time window shifted by another unit). In other words, the difference value is recalculated when a new sampling value is written to buffer memory 68. The difference value provides information about the size of particles in the two-phase mixture. The difference value allows for conclusions about the largest particle in the two-phase mixture. The difference value also represents the largest particle in the two-phase mixture, i.e., the suction flow. For example, if a large piece of paper passes through the measurement space, there will be a large fluctuation in the measurement value, i.e., the difference value will be large. If the two-phase mixture contains only small dust particles, the measurement value will be small, and therefore the difference value will also be small compared to the case of large particles.
[0066] The amplitude evaluation device 76 further has n low-pass filters 102.1 to 102.n arranged in parallel with each other, each receiving the difference value of the difference unit 100. The value n is an integer greater than 0, preferably 16. The low-pass filters 102.1 to 102.n have different time constants, and in this embodiment, these time constants t increase to the power of 2. This means, for example, that low-pass filter 102.1 has a time constant t of 2 ms, the second low-pass filter 102.2 has a time constant t of 4 ms, the third low-pass filter 102.3 has a time constant t of 8 ms, and the last low-pass filter 102.n has a time constant t of 2^nms. However, it should be noted that in this regard, these values are purely illustrative, but have been found to be particularly advantageous in one embodiment.
[0067] This series of low-pass filters 102 can be used to analyze the temporal progression of changing difference values. Therefore, a low-pass filter 102.1 with a small time constant can represent short-term changes in difference values better than a low-pass filter 102.n which can represent changes in difference values better over longer time intervals. As mentioned above, a large difference value indicates that a single large particle was detected by the measuring device, i.e., detected as a singular event. On the other hand, a very small difference value indicates that smaller particles are flowing through the measurement space.
[0068] By supplying the values from the low-pass filters 102.1 to 102.n to the weighted summing device 104, each value is multiplied by a weighting coefficient, and these weighted values are summed to form a single value, which is given to the output as value A2.
[0069] The weighting coefficients are supplied to the weighting summing device 104 in the form of application-specific weighting vectors 106, although each weighting coefficient may be different. Preferably, the sum of the weighting coefficients is 1. As mentioned above, it is convenient to provide the user with adjustable weighting vectors or a set of predetermined weighting vectors. Alternatively, naturally, the weighting vectors may be set at the factory, for example, after a calibration process.
[0070] Finally, Figure 5 shows the integral evaluation unit 78 as a block diagram. It comprises a summing unit 110 that receives values from the buffer memory 78, calculates the difference between the individual buffer values and the average value of the values in the buffer memory 78, and thereby sums the absolute values to form a single value. This calculation is performed for each new value written to the buffer memory 68.
[0071] The integral evaluation device 78 further comprises n low-pass filters 112.1 to 112.n, each arranged in parallel and supplied with the sum of the sum of the sum units 110. The value n is an integer greater than 0, preferably 16. In this regard, it should be noted that the number n of the low-pass filters 112 does not necessarily correspond to the number n of the low-pass filters 102 in the amplitude evaluation device 76, nor to the number n of the frequency range generated by the frequency converter 90. The number n can be the same or different.
[0072] The n low-pass filters 112.1 to 112.n have different time constants t, but these time constants preferably increase in powers of 2. In other words, for example, low-pass filter 112.1 has a time constant t of 2 ms, the second low-pass filter 112.2 has a time constant t of 4 ms, and the last low-pass filter 112.n has a time constant of 2^nms. Of course, these are exemplary values, but in practice it has been found to be particularly advantageous. These various low-pass filters allow for the analysis of the temporal change in the total value at the output of the total unit 110. Short-term changes can be identified by the first low-pass filter 112.1, while differences over longer time intervals can be detected by the last low-pass filter 112.n. For example, a smaller value A3 indicates a higher degree of cleaning. In other words, the cleaning results improve because fewer and fewer particles are flowing through the measurement space. A larger value indicates increased contamination, i.e., an increase in the amount of particles.
[0073] The number of n low-pass filters 112 is supplied to a weighted summer 114. Here, each value is multiplied by a weighting coefficient and then supplied to an adder, which calculates the sum. This value is given as the output value A3.
[0074] The weighting coefficients are supplied to the weighting summing device 114 in the form of a weighting vector 116, where the weighting vector is preferably adjustable by the user. The sum of the weighting coefficients is preferably 1, but may be different. It is also conceivable to store multiple different weighting vectors, and the user has the option to select a weighting vector. This means that the evaluation can be adapted to various cleaning or soiling conditions by adjusting the weighting.
[0075] In this regard, it should be noted that the weighting vectors 94, 106, and 116 mentioned above may be different. The optimal values of the weighting vectors are typically determined in the factory through a calibration process.
[0076] A series of digital values A1, A2, and A3 are supplied in time to a weighting summing device 80, where a value is formed by weighting and summing these values. The weighting coefficients used are preferably different, but their sum is 1. The three weighting coefficients are preferably adjustable to the user.
[0077] The sum or a series of sums is supplied to a low-pass filter 82 operating with a time constant of, for example, 0.1 seconds. The low-pass filter 82 smooths the values and supplies them to the transmitter 72. These values are supplied to the output device 33 via a digital interface 73 for representation, preferably optical representation. Optical representation can be performed using a display device 40 having a plurality of LEDs 42 of different colors. Thus, the display can indicate to the user a high level of dirt with red LEDs and a high level of cleanliness with green LEDs. At the same time, these values can be supplied to the control device 26 via the interface 73 so that, for example, the motor 14 can be controlled according to the level of dirt.
[0078] The evaluation device 30 described above can draw conclusions about the quality and quantity of particles in the two-phase mixture, as well as their changes over time, by analyzing the two-phase mixture in various ways. This evaluation can then be presented to the vacuum cleaner user in various ways, in which case an optical display is particularly convenient.
[0079] The evaluation itself can be performed digitally and can be parameterized with great flexibility. This makes it possible to provide an economical circuit that can be used very easily in various types of vacuum cleaners for a wide range of applications.
[0080] For example, the weighting vector can be adjusted in software using the digital interface 73. Device 30 can also communicate with a computer through this interface. Therefore, it is also possible to adjust parameters of, for example, an operating point monitoring device through this interface 73.
[0081] Finally, Figure 6 shows an example of how the device according to the present invention can be used. A robotic vacuum cleaner 120 having a suction motor 14 and a device 30 is shown. After the evaluation results are supplied to a higher-level control unit 26 via a digital interface 73, the control unit controls the drive motor 118. Thus, for example, the robotic vacuum cleaner can be moved more frequently to areas of the room with a high level of dirt. Alternatively or in addition, areas of the room that have already achieved a desired level of cleaning can be excluded from the area to be moved. This type of robotic vacuum cleaner control, which depends on the degree of cleaning, can save energy because it only approaches and vacuums areas that still have an undesirable high level of dirt. Also, due to the high accuracy of the evaluation, a good level of cleaning can be achieved without change.
Claims
1. In particular, a device for detecting and evaluating particles in the suction stream of a vacuum cleaner, A light source (34), in particular an infrared LED (35), is designed to emit light rays that pass through the measurement space (38) along the optical path (39), The optical sensor (36) is designed to receive the light rays after they have passed through the measurement space, and emits an analog measurement signal. Equipped with, An analog-to-digital converter (64) designed to convert the aforementioned analog measurement signal into a time-discrete digital measurement value, A buffer memory (68) designed to buffer a predetermined number of measurements, A frequency evaluation device (74) connected to the buffer memory, A frequency converter (90) designed to decompose the time-discrete measurement values from the buffer memory into frequency spectral values in a predetermined number n1 frequency range, A first weighted summing device (92) is designed to obtain a first weighted sum by multiplying each of the n1 frequency spectrum values by a first weighting value and adding the n1 weighted frequency spectrum values together, A transmitting device (72) is designed to provide the digital output signal from the frequency evaluation device to the digital output (73) as a digital output value for transmission, A device characterized by having a frequency evaluation device (74).
2. The device according to claim 1, characterized in that the frequency converter (90) comprises a fast Fourier transform (FFT) unit or a unit for executing the Gerzel algorithm.
3. The device according to claim 1 or 2, characterized in that the n1 first weighting values are adjustable.
4. The device according to any one of claims 1 to 3, characterized in that a first low-pass filter (96) to which the first weighted sum is supplied is provided.
5. The amplitude evaluation device (76) is connected to the buffer memory (68) on the input side, A difference unit (100) determines the maximum and minimum values of the aforementioned values stored in the buffer memory and generates a difference value based on these values, A first filter array including n2 low-pass filters (102.1 to 102.n) arranged in parallel with different time constants, each supplied with the difference value, A second weighted summing device (104) is designed to receive the individual values from the n2 low-pass filters (102), multiply each of the filtered values by a second weighting value (106), and sum the weighting values to form a total difference value. The device according to any one of claims 1 to 4, characterized by having an amplitude evaluation device (76).
6. The device according to claim 5, characterized in that the time constant of the low-pass filter (102) in the first filter array changes in a power of 2.
7. The device according to claim 5 or 6, characterized in that the n2 second weighting values are adjustable.
8. The integral evaluation device (78) is connected to the buffer memory (68) on the input side, A summing unit (110) generates an integral value which is the sum of the absolute values of the differences between the value in the buffer memory and the average value of all the values in the buffer memory, A second filter array comprising n3 parallel low-pass filters (112.1 to 112.n) having different time constants, each to which the integral value is supplied, A third weighted summing device (114) is designed to receive the individual values from the n3 low-pass filters of the second filter array, multiply each of the received values by a third weighting value, and sum the weighting values to form a total integral value. The device according to any one of claims 1 to 7, characterized by having an integral evaluation device (78).
9. The device according to claim 8, characterized in that the time constant of the low-pass filter in the second filter array changes in a power of 2.
10. The device according to claim 8 or 9, characterized in that the n3 third weighting values are adjustable.
11. The device according to any one of claims 1 to 10, comprising a fourth weighted summing device (80) designed to receive the values from the frequency evaluation device, the amplitude evaluation device, and the integral evaluation device, multiply each of the supplied values by a fourth weighting value, and sum the weighting values to form a total output value.
12. The device according to claim 11, characterized by a low-pass filter (82) whose output flows to the transmitting device (72) and whose input is connected to the fourth weighting summing device (80).
13. The device according to any one of claims 1 to 12, characterized in that the buffer memory surface (68) is designed as a ring memory.
14. The device according to any one of claims 1 to 13, wherein a first operational amplifier (52) and a second operational amplifier (54) are provided, the first operational amplifier controls the light source (34), and the second operational amplifier is connected to the light sensor (36) on the input side and outputs the analog measurement signal on the output side.
15. The device according to claim 14, characterized in that the signal from the light sensor is supplied to the first operational amplifier (52), and the first operational amplifier controls the light source with a control signal based on this signal so that the signal from the light sensor has a predetermined value.
16. The device according to claim 15, further characterized by being provided with a monitoring unit (70) designed to monitor the control signal and to notify when the control signal exceeds a predetermined, in particular, pre-defined value.
17. The device according to claim 16, characterized in that the control signal is supplied to another analog-to-digital converter (66), and its digital output value is monitored by the monitoring unit (70).
18. The device according to any one of claims 1 to 17, characterized in that n1, n2, and n3 are each integers, preferably integers greater than 1.
19. Emitting light rays that pass through the measurement space along the optical path, The process involves receiving the light rays after they have passed through the measurement space with a light sensor, and the light sensor emitting an analog measurement signal. Converting the aforementioned analog measurement signal into a digital measurement value, The process involves buffering a predetermined number of digital measurement values into a buffer memory, and decomposing the time-discrete measurement values from the buffer memory into frequency spectral values in a predetermined number n1 frequency range. The process involves multiplying each of the n1 frequency spectrum values by a first weighting value, adding the n1 weighted frequency spectrum values together, and obtaining a first weighted total value. The process includes providing the results of the frequency evaluation as a digital output value. This involves performing a frequency evaluation of the value in the buffer memory, Methods that include...
20. The maximum and minimum values of the aforementioned values stored in the buffer memory are determined, and the difference value is generated based on these values. Filtering the difference value through a first filter array including n2 low-pass filters arranged in parallel with different time constants, Each of the filtering values is multiplied by a second weighting value, and the weighting values are summed to form a total difference value. The method according to claim 19, characterized in that it performs amplitude evaluation of the measured values stored in the buffer memory.
21. The absolute values of the differences between the value in the buffer memory and the average value of all the values in the buffer memory are summed and output as an integral value. Filtering the integral value through a second filter array including n3 parallel low-pass filters, each having a different time constant and to which an integral value is supplied; The filtering integral values from each of the n3 low-pass filters are multiplied by a third weighting value, and the weighting values are summed to form a total integral value. The method according to claim 20, characterized in that an integral evaluation of the measured values stored in the buffer memory is performed by this method.
22. A device according to any one of claims 1 to 18, Suction nozzle and Suction motor (12) and A tube (14) between the suction nozzle and the suction motor (12), through which the inhaled air flows, and a portion of the tube (14) surrounds the measurement space (38), The first translucent region in the tube portion to which the light source (34) is assigned, A second translucent region in the tube portion located opposite the first region, to which the light sensor (36) is assigned, and the optical path (39) extends from the first region to the second region, A control device (26) connected to the transmitting device, which receives the digital output value and uses it for control purposes, and / or An output device (33) connected to the transmitting device, which receives the digital output value and uses it for optical and / or acoustic representation, A cleaning system comprising, in particular, an electric vacuum cleaner (10, 120).
23. The cleaning system according to claim 22, characterized in that the control device (26) is designed to adjust the power of the suction motor based on the output value.
24. The cleaning system according to claim 22 or 23, characterized in that it is provided with output devices (33, 40) that visually and / or acoustically represent the output value.
25. The cleaning system according to any one of claims 22 to 24, wherein the cleaning system is a robotic vacuum cleaner (120) including a controllable drive unit (118) for moving and cleaning on a surface, and the output value is included in the control of the drive unit.