Monitoring system for movable components connected to stationary components

Abstract

A monitoring system (12) for a movable component (3), for example a rotating component, supported by a fixed component (2). The monitoring system (12) comprises an acoustic sensor (10) located in the movable component (3) and comprising two terminals (17), a first amplifier (18) located within the movable component (3) and having two inputs and two outputs, a contactless communication unit (14) having a first transceiver device (15) located in the movable component (3) and a second transceiver device (16) facing the first transceiver device (15) and located in the fixed component (2), a first connection line (19) connecting the sensor (10) to the first amplifier (18) and having two electrical leads each connecting a terminal (17) of the acoustic sensor (10) to a respective input terminal of the first amplifier (18), and a second connection line (20) connecting the first amplifier (18) to the first transceiver device (15) and having two electrical leads each connecting an output of the first amplifier (18) to the first transceiver device (15).

Description

Technical Field

[0001] This invention relates to a monitoring system for a movable component (e.g., a rotating component) connected to a fixed component.

[0002] The present invention can be advantageously applied to monitoring systems that use acoustic signals to support the rotating spindle of (at least) a grinding wheel in a machine tool, the following discussion of which will be explicitly referenced without loss of generality. Background Technology

[0003] For example, as described in patent applications No. EP0690979A1, EP1870198A1, and EP3134980A1, it is known that the rotary spindle (hub) of a machine tool (especially a grinding machine) supports (at least) a grinding wheel and has a balancing head housed in an axial cavity. The balancing head includes at least one balancing block eccentric relative to the rotary axis, the position of which is adjustable and controlled by an electric motor.

[0004] Typically, the balancing head also includes a vibration sensor (i.e., a microphone) to detect ultrasonic emissions caused by contact between the grinding wheel and the workpiece or between the grinding wheel and the dressing tool (dresser). The electrical signal generated by the vibration sensor is used (in a known manner) to control the machining cycle.

[0005] The microphone is part of the monitoring system, where the electrical signals it provides are processed to provide information about the correctness of the machining process. The machine tool's control unit can then act on the process based on this information. Summary of the Invention

[0006] The object of the present invention is to provide a monitoring system for a movable part connected to a fixed part, which allows for accurate and stable detection of the effects of an ongoing action, such as workpiece machining or grinding wheel dressing, and is preferably easy to install even in confined spaces.

[0007] The present invention provides a monitoring system for connecting a movable component to a fixed component, as defined in the appended claims.

[0008] The claims describe embodiments of the invention and form part of this specification. Attached Figure Description

[0009] The invention is described with reference to the accompanying drawings, which illustrate non-limiting examples of embodiments, wherein:

[0010] Figure 1 A machine tool with a rotating spindle supporting a grinding wheel and having a balancing head is schematically shown.

[0011] Figure 2 A monitoring system according to the present invention is illustrated schematically; and

[0012] Figure 3-7 yes Figure 2 A series of schematic diagrams illustrating alternative embodiments of the monitoring system. Detailed Implementation

[0013] exist Figure 1 In the accompanying drawings, reference numeral 1 represents a machine tool (particularly a grinding machine) as a whole, showing only some of its components.

[0014] Typically, a machine tool consists of a fixed part or fixed component connected to each other, and a movable part or movable component. In a grinding machine, the movable component usually rotates relative to the fixed part.

[0015] Figure 1 The machine tool 1 shown includes a frame 2 (i.e., a fixed part) that rotatably supports a spindle 3 that rotates about a rotation axis 4 (by means of bearings arranged therebetween).

[0016] The spindle 3 supports the grinding wheel 5 via a corresponding grinding wheel hub, which is detachably fixed to the spindle 3 by a known (but not shown) device including, for example, a tapered coupling. The spindle 3 and the grinding wheel hub define the rotating part of the machine tool 1, also referred to as the rotor. The spindle 3 has an axial opening 6 at its center for accommodating a balancing head 7. The balancing head 7 of a known type includes two balancing blocks 8 eccentric relative to the axis of rotation 4 and corresponding motors 9 for adjusting the angular position of the balancing blocks 8. The rotating part also includes (at least) a sound sensor 10 or a vibration sensor. Figure 1 In this configuration, the acoustic sensor 10 is integrated into the balancing head 7, but it can also be disposed in different areas of the rotating component, for example... Figure 2 As shown.

[0017] The function of the balancing head 7 is to balance the grinding wheel 5. This operation is generally performed when changing the grinding wheel 5, or when it is necessary due to wear of the grinding wheel 5.

[0018] The balancing head 7 includes a control device 11, which controls the operation of the balancing head 7.

[0019] The balancing head 7 described and shown in the attached figures may not exist, and the rotating part may only include acoustic sensor 10 or more acoustic sensors.

[0020] The acoustic sensor 10 and the balancing head 7 (if provided) are part of a monitoring system 12, which is connected to a processing unit 40 configured in a fixed position (i.e., supported by the frame 2 of the machine tool 1). The monitoring system 12 is configured to provide signals to the processing unit 40, mounted on the frame 2 (i.e., in the fixed part of the machine tool 1), relating to the vibrations experienced by the spindle 3 (i.e., the rotating part of the machine tool 1) at the grinding wheel 5, as experienced by the machine tool 1.

[0021] Figure 2-6 The monitoring system 12 is shown, in which the sound sensor 10 and Figure 1 The implementation is different and is not integrated into the balance head 7.

[0022] The dashed box in the figure represents the physical division between the rotating and stationary parts of the machine tool; the configuration of individual components of the monitoring system 12 may differ from that shown in the figure.

[0023] like Figure 2 As shown, the monitoring system 12 includes a non-contact communication unit 14 having a first transceiver device 15 located in the spindle 3 (i.e., the rotating part of the machine tool 1) and a second transceiver device 16 facing the transceiver device 15 and positioned in the frame 2 (i.e., in the fixed part of the machine tool 1). The two transceiver devices 15 and 16 are adapted to communicate with each other in a non-contact and known manner to transmit information from the transceiver device 15 to the transceiver device 16 and vice versa. The fixed part includes an interface unit 13 that distributes power to the components of the monitoring system 12 and transmits signals leaving or entering the processing unit 40.

[0024] The communication unit 14 is used by the interface unit 13 in one direction to send control signals (e.g., start / stop readings of the acoustic sensor 10 or motor 9 controlling the balance block 8 of the balance head 7) from the processing unit 40 and / or from the control unit (not shown) of the machine tool, and in the opposite direction to transmit diagnostic signals (generated in the balance head 7) to the interface unit 13 and / or signals related to vibrations experienced by the spindle.

[0025] like Figure 2 As shown, the acoustic sensor 10 includes two terminals 17, between which a variable voltage (i.e., an analog signal) is generated, which depends on the intensity and frequency of the vibration detected by the vibration sensor 10 itself.

[0026] The monitoring system 12 includes an amplifier 18, which is placed inside the rotor (i.e., in the rotating part of the machine tool 1) and includes two input terminals and two output terminals.

[0027] The monitoring system 12 includes a first connection line 19 that connects the acoustic sensor 10 to the amplifier 18 and includes two separate (i.e. electrically insulated) leads, each of which connects the terminal 17 of the vibration sensor 10 to the corresponding input terminal of the amplifier 18.

[0028] The monitoring system 12 includes a second connection line 20 that connects the amplifier 18 to the transceiver device 15 and includes two separate (i.e. electrically insulated) leads, each of which connects the output terminal of the amplifier 18 to the transceiver device 15.

[0029] Specifically, amplifier 18 is positioned close to acoustic sensor 10.

[0030] exist Figure 1 In the illustrated embodiment, the acoustic sensor 10 is integrated into the balancing head 7, and the amplifier 18 may be located in the control device 11 of the balancing head 7 or integrated into the acoustic sensor 10. The connecting wire 20 is integrated into the multiply cable 21, preferably coiled, which extends along the axial opening 6 and includes one or more power lines (i.e., lines that transmit power for operating the balancing head 7) in addition to the connecting wire 20.

[0031] exist Figure 2 In the illustrated embodiment, communication unit 14 transmits analog signals non-contactly via inductive coupling. According to different embodiments (not shown), communication unit 14 transmits analog signals non-contactly via optical coupling (e.g., one of the alternatives described in patent number US5688160A). Transceiver device 15 receives voltage and current varying according to vibrations detected by acoustic sensor 10 and transmits (induces) the corresponding voltage and current via inductive coupling to transceiver device 16. Thus, an electronic analog signal exits transceiver device 16. Preferably, monitoring system 12 includes amplifier 22 located in rack 2 (i.e., in the fixed portion of machine tool 1) and includes two input terminals connected to transceiver device 16 and two output terminals connected to interface unit 13, which, as previously described, is configured to process signals generated by acoustic sensor 10.

[0032] The monitoring system 12 includes a power supply circuit 23 with a first power supply unit 24 located in the rotor (i.e., in the rotating part of the machine tool 1) and supplying power to the amplifier 18, and a second power supply unit 25 located in the frame 2 (i.e., in the fixed part of the machine tool 1), supplying power to the amplifier 22 and the power supply unit 24, and receiving power from the interface unit 13. Due to the presence of amplifiers 18 and 22 (which require power), signal conditioning is improved and more robust than in the case of a direct connection between the acoustic sensor 10 and the transceiver device 15. Furthermore, the power supply circuit 23 includes an air-coupled transformer 26 with a first coil 27 located in the rotor (i.e., in the rotating part of the machine tool 1) and supplying power to the power supply unit 24, and a second coil 28 located in the frame 2 (i.e., in the fixed part of the machine tool 1) and receiving power from the power supply unit 25. Figure 2 In the illustrated embodiment, the power supply device 24 is directly connected to the coil 27 of the air coupling transformer 26; that is, the power supply device 24 receives power directly from the coil 27 of the air coupling transformer 26 without a medium.

[0033] Figure 2A separate power supply circuit 29 is also shown, which is completely separate and independent from the power supply circuit 23 of the monitoring system 12 and supplies power to the balancing head 7. This power supply circuit 29 is present when the balancing head 7 is present. The power supply circuit 29 includes, for example, a power supply device 30 located in the rotor (i.e., in the rotating part of the machine tool 1) and supplying power to the balancing head 7, and a power supply device 31 located in the frame 2 (i.e., the fixed part of the machine tool 1) supplying power to the power supply device 30 via an air coupling transformer 32 and receiving power from the interface unit 13.

[0034] exist Figure 2-5 In the illustrated embodiment, the balancing head 7 is powered by a power supply circuit 29, which supplies power only to the balancing head 7 and is independent of the power supply circuit 23 of the monitoring system 12. Figure 6 In the illustrated embodiment, only the power supply circuit 23 is provided, and it is shared by the entire monitoring system 12, including the balancing head 7. In other words, the power supply circuit 23 also supplies power to the balancing head 7.

[0035] exist Figure 3 In the alternative embodiment shown, the monitoring system 12 includes another amplifier 33 located in the rotor (i.e., in the rotating part of the machine tool 1), connected in series with the amplifier 18 along the connecting line 20, and including two input terminals connected to the two output terminals of the amplifier 18 and two output terminals connected to the transceiver device 15. Specifically, the amplifier 18 is configured near the vibration sensor 10 (i.e., at the beginning of the connecting line 20, referring to the layout shown in the figures), while the amplifier 33 is configured near the transceiver device 15 (i.e., to the end of the connecting line 20, referring to the layout shown in the figures).

[0036] exist Figure 3 In the embodiment shown, amplifier 33 is also powered by power supply device 24, which powers amplifier 18.

[0037] exist Figure 4 In the alternative embodiment shown, the monitoring system 12 includes a third power supply 34 directly connected to the coil 27 of the air-coupled transformer 26; in other words, the power supply 4 receives power directly from the coil 27 of the air-coupled transformer 26 without a medium. Furthermore, the monitoring system 12 includes a coupling device 35 that receives power from the power supply 34 and feeds it to the connection line 20 at a frequency band different from the analog signal generated by the acoustic sensor 10, and a decoupling device 36 that draws power from the connection line 20 and supplies power to the power supply 24 (which thus indirectly receives power from the coil 27 of the air-coupled transformer 26). For example, the coupling device 35 and the decoupling device 36 use reactive components to achieve band separation and transmit continuous or alternating power with frequencies higher or lower than the analog signal generated by the acoustic sensor 10, typically between 1 kHz and 1 MHz.

[0038] exist Figure 2-4 In the illustrated embodiment, communication unit 14 transmits analog signals (which will be digitized in processing unit 40) between two transceiver devices 15 and 16. Figure 5-7 In the illustrated embodiment, communication unit 14 transmits digital signals between two transceiver devices 15 and 16. Monitoring system 12 actually includes an analog-to-digital converter 37 located in the rotor (i.e., in the rotating part of machine tool 1) and configured to receive analog signals from amplifier 18 (if provided, together with amplifier 33) and convert the analog signals into digital signals.

[0039] Furthermore, the monitoring system 12 preferably includes a processing device 38 located in the rotor (i.e., in the rotating part of the machine tool 1) and configured to receive digital signals from the analog-to-digital converter 37, process the digital signals and obtain the processed digital signals, and provide the processed digital signals to the transceiver device 15.

[0040] More specifically, the processing device 38 performs time-domain and frequency-domain processing on the digital signal exiting the analog-to-digital converter 37. Preferably, this processing is based on Fourier transform calculations.

[0041] More specifically, this process is performed using the Fast Fourier Transform (FFT).

[0042] For example, signal processing may include the following steps:

[0043] - Select the signal's frequency band and set the gain;

[0044] - Sample the signal at a frequency higher than 2MHz;

[0045] - Calculate the FFT function;

[0046] - Returns to zero in the frequency domain;

[0047] - Demodulate the signal spectrum to perform checks related to clearance (i.e., the distance between the grinding wheel and the workpiece or dressing tool) and checks related to collision (i.e., the contact between the grinding wheel and the workpiece or dressing tool or other components of the machine tool), and demodulate the two types of checks independently;

[0048] - Perform time-domain processing on the signal for each of the two independent types of checks;

[0049] - Automatic execution of parameterization of the trigger frequency band and signal gain, and triggering the zeroing of background noise.

[0050] Alternatively, the background noise can be zeroed out based on its average or maximum value.

[0051] Processing the coarse signal, i.e. the signal generated by the acoustic sensor 10, inside the rotor allows the full signal processing (e.g., including the steps described above) to be performed as close as possible to the signal source (i.e., the acoustic sensor 10) and significantly shortens the propagation path of the coarse signal.

[0052] In known solutions, the analog signal generated by the sensor is transmitted to an external processor, which converts the analog signal into a digital signal for processing. The processor is typically located in a control room or laboratory, and processing can be performed without strict limitations. However, due to the potentially long propagation path of the analog signal, the signal-to-noise ratio often deteriorates, and the signal quality reaching the processor is significantly worsened.

[0053] According to known solutions, the signal generated by the sensor is digitized near the sensor and then transmitted to an external processor for complete processing. However, the bandwidth required to transmit the digital signal is too large for contactless communication systems in industrial applications. This problem has been overcome in known solutions by obtaining the digital signal through differential quantization (e.g., 8-bit) and performing only minimal digital processing before transmission. In this way, the bandwidth of the signal to be transmitted is limited, but the poor digital processing performed before signal transmission inevitably leads to low-performance signal processing in the external processor.

[0054] The monitoring system 12 according to the invention allows for the conversion, and especially complete processing, of signals generated by the acoustic sensor 10 adjacent to such a sensor by simultaneously meeting the requirements of such applications, namely, highly miniaturized, very low power consumption, and low bandwidth transmission of detailed information related to process monitoring.

[0055] This is achieved by combining a processing unit with lower computational power with highly optimized software algorithms. In fact, the hardware of the processing unit is designed to have lower computational power than that typically used in such applications in order to reduce overall size and power consumption, while the software is designed to perform all the operations required for monitoring, but with fewer resources.

[0056] According to a preferred embodiment of the present invention, in order to obtain the processed digital signal inside the rotor and to transmit the processed digital signal via a contactless communication unit 14, a monitoring system 12, and more specifically, an analog-to-digital converter 37 and a processing device 38, a method comprising the following steps is implemented:

[0057] - Increase the dynamics of analog-to-digital acquisition by using a SAR (Successive Approximation Buffer) converter with higher resolution compared to known solutions.

[0058] - Perform high-frequency acquisition of the rough fundamental frequency signal generated by the acoustic sensor 10, the frequency of which is higher than 2MHz.

[0059] - Randomization is applied to individual measurements. This randomization process is highly parameterizable to maintain efficiency as the monitored process changes. More specifically, the digital randomization technique used guarantees stability and convergence.

[0060] - An automatic parameter setting mode is implemented, allowing for the automatic parameterization of the process based on observations of the monitored process. The process parameters produce acoustic emissions detected and monitored by acoustic sensors, which are not prior to the observed parameters because they depend on numerous operational and environmental conditions. The implemented automatic parameter setting mode is defined based on one or more learning phases and subsequent processing of the acquired results.

[0061] The processing result, i.e., the processed digital signal, is encapsulated to enable real-time transmission of high-priority and low-priority information over the same communication channel. As mentioned earlier, digital processing technology generates large amounts of data, thus requiring significant bandwidth for signal transmission. The encapsulation of the processed digital signal is performed according to an optimized communication protocol that allows defining the hierarchical structure of information based on the latency of information usage. This enables the transmission of the processed digital signal via a contactless communication channel, as provided in the monitoring system according to the invention.

[0062] Preferably, the method further includes a specific process of performing multiple simultaneous measurements based on the same coarse signal without requiring the addition of dedicated hardware. Machine tool applications using acoustic sensors typically perform at least two types of measurements: machine operation-related measurements with high sensitivity and narrow bandwidth to track the machine process with maximum accuracy, and monitoring measurements with lower sensitivity and wider bandwidth to identify anomalies promptly, even outside the typical process bandwidth.

[0063] The combination of hardware and software designed as described above allows for complete processing of the signal generated by the acoustic sensor 10 inside the rotor. This means that the signal processing not only has good quality and a good signal-to-noise ratio, but also carries the risk of information loss because it has not undergone partial processing beforehand.

[0064] exist Figure 5 In one embodiment, transceiver device 15, analog-to-digital converter 37, and processing device 38 receive power from power supply device 34, while transceiver device 16 receives power from power supply device 25.

[0065] Figure 5 The illustrated embodiments and Figure 6 The only difference in the illustrated embodiment is that, Figure 5 In the illustrated embodiment, the power supply circuit 29 supplying power to the balancing head 7 is separate and independent from the power supply circuit 23, while... Figure 6In the embodiment shown, only the power supply circuit 23 is provided and is shared by the entire monitoring system 12, including the balance head 7 (in other words, the power supply circuit 23 also provides power to the balance head 7).

[0066] According to different embodiments not shown in the figures, the analog-to-digital converter 37 and the processing unit 38 are configured in the frame 2 (i.e., in the fixed part of the machine tool 1). The conversion of analog signals to digital signals and their processing are not performed in the rotating parts of the machine tool, but in the fixed part of the machine tool. This solution can be applied to... Figure 5 , 6 Alternative embodiments of the monitoring system 12 shown in Figure 7.

[0067] exist Figure 7 In the illustrated embodiment, the monitoring system 12 includes two acoustic sensors 10, two separate and independent amplifiers 18, and two connecting lines 19, each connecting line connecting one of the acoustic sensors 10 to the amplifier 18 and including two independent electrical leads. Furthermore, the monitoring system 12 includes a single communication unit 14 (shared between the two acoustic sensors 10) and a multiplexer 39 having two inputs connected to the two amplifiers 18 and a single output of a transceiver device 15 connected to the single communication unit 14. The multiplexer 39 is an input selector that receives several analog input signals and alternately sends them to the single output. The multiplexer 39 allows for multiple sensors located in different areas of the rotor and selects the signal from the most effective sensor for monitoring purposes based on the operations performed through the machine tool.

[0068] Obviously, when a single communication unit 14 transmits digital signals (such as...) Figure 7 As shown) and when a single communication unit 14 transmits analog signals, i.e., when the monitoring system 12 does not include an analog-to-digital converter 37, two (or more) acoustic sensors 10 may exist, and thus a multiplexer 39 may be present. Furthermore, when a power supply 34 is provided to each power supply unit 24 using coupling devices 35 and decoupling devices 36, and when each power supply unit 24 is directly connected to the winding 27 of the air-coupled transformer 26, two (or more) vibration sensors 10 may exist, and thus a multiplexer 39 may be present (e.g., as shown). Figure 7 (As shown).

[0069] According to one possible embodiment, the processing device 38 controls the multiplexer 39 to control which acoustic sensor 10 must provide a signal to the transceiver device 15 of the individual communication unit 14, i.e., which acoustic sensor 10 must be read. The multiplexer 39 can be statically assigned, or alternatively, dynamically configured, i.e., connecting each input to the output in a cyclical and alternating manner at a defined switching frequency. When the processing device 38 is configured in a rotor (e.g.... Figure 7When the multiplexer 39 is configured in the fixed part of the machine tool (as shown), it can be controlled by the processing device 38.

[0070] exist Figure 7 In the illustrated embodiment, two acoustic sensors 10 are provided and connected to the multiplexer 39 (via a corresponding amplifier 18). According to other embodiments not shown in the figures, three or more acoustic sensors 10 are provided and connected to the multiplexer 39 (via a corresponding amplifier 18); all of these sensors, or some of them, cannot be acoustic sensors.

[0071] So far, the presence of multiple acoustic sensors and multiplexers has been shown and described with reference to monitoring system 12, wherein signal processing occurs in either the stationary or rotating parts of the machine tool. As mentioned above, multiple sensors and multiplexers may also be present. Figure 2-4 In an alternative embodiment of the monitoring system 12 shown, signal processing occurs in the processing unit 40. In these cases, the processing unit 40 controls the multiplexer.

[0072] Traditionally, the processing unit 40 uses the readings of the acoustic sensor 10 only during workpiece machining or during grinding wheel maintenance or dressing to detect ultrasonic emissions caused by contact between the grinding wheel and the workpiece or between the grinding wheel and the dressing tool (dresser). Therefore, the readings of the vibration sensor 10 are traditionally (in a known manner) used only to check machining or maintenance cycles.

[0073] Due to accidental collisions between spindle 3 and the workpiece and / or between spindle 3 and other components of machine tool 1 (and due to control errors), processing unit 40 may also use readings from acoustic sensor 10 to detect any vibration peaks (i.e., peaks of acoustic emission) during the movement of spindle 3 back and forth to the workpiece and / or during the assembly and disassembly of the workpiece. In other words, acoustic sensor 10 (i.e., the monitoring system 12 includes acoustic sensor 10) is used by processing unit 40 as a “sentinel” for any unwanted collisions with spindle 3 when spindle 3 shifts or the workpiece approaches spindle 3. Obviously, when a signal provided by acoustic sensor 10 indicates a (possible) collision, processing unit 40 immediately sends it to the machine tool’s control unit, stopping the ongoing motion if necessary. This type of event may also be recorded by processing unit 40 and / or the machine tool’s control unit to allow for the reconstruction of all negative events experienced by spindle 3 in the future.

[0074] In the above embodiment, a vibration sensor 10 is used, while in other embodiments (not shown), different types of sensors (e.g., temperature sensors, pressure sensors, acceleration sensors, etc.) are used.

[0075] In the above embodiment, the movable part is the spindle 3 of the machine tool 1, while in other embodiments (not shown), the movable part is a component with different functions in the machine tool 1 or other types of machines.

[0076] The embodiments described herein can be combined with each other without departing from the scope of protection of this invention.

[0077] The aforementioned monitoring system 12 offers several advantages.

[0078] First, the aforementioned monitoring system 12 allows for an improved signal-to-noise ratio by enhancing the accuracy, sensitivity, and stability of the readings from the acoustic sensor 10. This result is particularly due to the presence of a transmission line suitable for providing differential signals. A transmission line defines a signal path. Throughout the transmission line, the signal path is fully differential, meaning that the inputs and outputs of each component forming part of the transmission line are differential, and the operations performed by each component are differential.

[0079] The transmission line starts from the acoustic sensor 10, includes a first connecting line 19, an amplifier 18, and a second connecting line 20, and ends at the transceiver device 15 of the communication unit 14. Throughout its path, the signal is always fully differential and has high quality and strong disturbance rejection capability.

[0080] According to a preferred embodiment, the transmission line for the differential signal runs from the acoustic sensor 10 through the communication unit 14 (also configured to maintain a fully differential signal path), amplifier 22, interface unit 13, and corresponding electrical leads to the processing unit 40. In other words, according to the preferred embodiment, there is also a contactless communication unit 14, and the amplifier 22 includes two input terminals connected to the second transmission device 16 and two output terminals connected to the interface unit 13, the interface unit (13) itself and any electrical leads connecting the latter to the processing unit 40 forming part of the transmission line providing the differential signal.

[0081] exist Figure 4-7 In the illustrated embodiment, a single connection line 20 allows the electrical power and signal from the vibration sensor 10 to the acoustic sensor 10. This allows for a significant reduction in the number of electrical leads required for the system, offering a clear advantage in miniaturization.

[0082] exist Figure 7 In the embodiments shown, the more inputs the multiplexer has, the greater the aforementioned advantages become.

[0083] Figure 5-7 In the embodiment shown, the analog signal generated by the acoustic sensor 10 is digitized in the rotor, so the communication unit 14 transmits the digital signal in a non-contact manner. This digital signal is different from the analog signal and is not affected by noise or attenuation.

[0084] exist Figure 5-7In the illustrated embodiment, the signal generated by the acoustic sensor 10 is already processed in the movable part (or, according to an alternative embodiment not shown, in the fixed part) due to the presence of the processing device 38, which can significantly improve the signal-to-noise ratio.

[0085] In addition to the advantages mentioned above, performing complete or most of the signal processing inside the rotor offers even more significant advantages.

[0086] First, because the monitoring system, more specifically the rotor, is more powerful and autonomous—meaning it autonomously performs more complex operations—the workload of the control unit is significantly reduced. Therefore, the system can be improved by increasing, for example, the number and / or types of processes being monitored, such as adding more sensors and / or performing more types of checks.

[0087] Furthermore, performing complete or most of the signal processing inside the rotor allows for the possibility of self-configuring the monitoring system based on the processed signals, as well as the possibility of implementing self-diagnostic functions within the monitoring system, such as measuring temperature, voltage, or other system parameters, and checking the reliability of communication channels.

[0088] The processing of the signal generated by the acoustic sensor 10 can occur in a movable part (or, according to an alternative embodiment not shown, in a fixed part), even in a monitoring system that does not include a transmission line suitable for providing differential signals.

[0089] Similarly, multiplexers can be used in monitoring systems that include multiple sensors (and a balance head, if present) but do not include transmission lines suitable for providing differential signals.

Claims

1. A monitoring system (12) for connecting a movable part (3) to a fixed part (2), the monitoring system being connected to a processing unit (40), and comprising: An acoustic sensor (10) is located in the movable part (3) and includes two electrical terminals (17); a variable voltage, i.e. an analog signal, is generated between the two electrical terminals as the intensity and frequency of the vibration detected by the acoustic sensor (10) change. The first amplifier (18) is located in the movable part (3) and includes two electrical input terminals and two electrical output terminals; The contactless communication unit (14) has a first transceiver device (15) disposed in the movable component (3) and a second transceiver device (16) facing the first transceiver device (15) and disposed in the fixed component (2); A first connecting line (19) connects the acoustic sensor (10) to the first amplifier (18); and The second connecting line (20) connects the first amplifier (18) to the first transceiver device (15); The monitoring system (12) is characterized in that it includes a transmission line suitable for providing differential signals, the transmission line comprising: The first amplifier (18) includes two electrical input terminals and two electrical output terminals; The first connecting line (19) includes two electrical leads, each of which connects an electrical terminal (17) of the acoustic sensor (10) to a corresponding electrical input terminal of the first amplifier (18); and The second connecting line (20) includes two electrical leads, each of which connects the electrical output terminal of the first amplifier (18) to the first transceiver device (15); The transmission line defines a signal path, which is fully differential in the transmission line, such that the input and output of each component constituting a part of the transmission line are differential, and the operation performed by each component is a differential operation. The first connecting line (19) includes two independent and electrically insulated electrical leads, each of which connects the corresponding electrical terminal (17) of the acoustic sensor (10) to the corresponding electrical input terminal of the first amplifier (18). The second connecting line (20) includes two independent and electrically insulated electrical leads, each of which connects the corresponding electrical output terminal of the first amplifier (18) to the first transceiver device (15).

2. The monitoring system (12) according to claim 1 includes a second amplifier (33) placed in the movable part (3), connected in series with the first amplifier (18) along the second connecting line (20), and includes two electrical input terminals connected to the two electrical output terminals and two electrical output terminals of the first amplifier (18), and connected to the first transceiver device (15).

3. The monitoring system (12) according to claim 1, comprising a third amplifier (22) placed in the fixed component (2) and including two electrical input terminals connected to the second transceiver device (16) and two electrical output terminals connectable to an interface unit (13), the interface unit (13) being configured to distribute power supply and transmit signals leaving or entering the processing unit (40).

4. The monitoring system (12) according to claim 1, comprising an analog-to-digital converter (37) disposed in the movable component (3) or the fixed component (2) and configured to receive analog signals and convert the analog signals into digital signals.

5. The monitoring system (12) according to claim 4, comprising a processing device (38) placed in the movable part (3) or the fixed part (2) and configured to receive the digital signal from the analog-to-digital converter (37), process the digital signal, and obtain and output the processed digital signal.

6. The monitoring system (12) according to claim 1, wherein, The transmission line is adapted to provide a differential signal, starting from the acoustic sensor (10) and ending at the processing unit (40) connected to the monitoring system (12).

7. The monitoring system (12) according to any one of claims 1 to 6, and comprising a power supply circuit (23), having: A first power supply device (24) is placed in the movable component (3) and provides power to the first amplifier (18); and An air-coupled transformer (26) includes a first coil (27) placed in the movable part (3) and supplying power to the first power supply device (24), and a second coil (28) placed in the fixed part (2) and receiving power.

8. The monitoring system (12) according to claim 7, and comprising a second power supply device (25) disposed in the fixed component (2) to provide power to the second coil (28) and to provide power to a third amplifier (22) disposed in the fixed component (2) or to the second transceiver device (16).

9. The monitoring system (12) according to claim 7, further comprising: The third power supply device (34) is directly coupled to the first coil (27); The coupling device (35) receives power from the third power supply device (34) and feeds the power to the second connection line (20), the power being in a frequency band different from the frequency band of the analog signal generated by the acoustic sensor (10); and A decoupling device (36) that draws power from the second connection line (20) and supplies power to the first power supply device (24).

10. The monitoring system (12) according to claim 8, further comprising: The third power supply device (34) is directly coupled to the first coil (27); The coupling device (35) receives power from the third power supply device (34) and feeds the power to the second connection line (20), the power being in a frequency band different from the frequency band of the analog signal generated by the acoustic sensor (10); and A decoupling device (36) that draws power from the second connection line (20) and supplies power to the first power supply device (24).

11. The monitoring system (12) according to any one of claims 1 to 6, comprising a balancing head.

12. The monitoring system (12) according to claim 9, comprising a balancing head, wherein, The third power supply device (34) is also connected to the balance head (7) to provide power to the balance head (7).

13. The monitoring system (12) according to any one of claims 1 to 6, and comprising: Two separate and independent acoustic sensors (10); Two first amplifiers (18); Two first connecting lines (19), each of which connects the acoustic sensor (10) to the first amplifier (18) and includes two electrical leads; Single communication unit (14); and The multiplexer (39) has two electrical input terminals connected to the two first amplifiers (18) and a single electrical output terminal connected to the first transceiver device (15) of the single communication unit (14).

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