Sensor system simulating variable differential transformer

Abstract

Embodiments of the present disclosure relate to a system including a controller, a position sensor, and an emulator circuit. The controller is configured to output an AC excitation signal and receive a first AC response signal and a second AC response signal. The controller is configured to determine a location of the effector based on the first alternating response signal and the second alternating response signal. The position sensor is configured to be connected to the effector, and the position sensor is configured to output a position signal based on a position of the effector. The emulator circuit is configured to modulate an amplitude and a frequency of the position signal based on the AC excitation signal to generate a first AC response signal and a second AC response signal.

Description

Technical Field

[0001] The present invention relates generally to sensor systems and, more particularly, to position sensing systems. Background Art

[0002] Applicants expect that replacing a linear variable differential transformer (LVDT) or a rotary variable differential transformer (RVDT) with other types of sensors may provide certain advantages. For example, Applicants have discovered that LVDTs and RVDTs are relatively large sensors that dictate the final size of the device to which they are attached for position sensing. In addition, Applicants have discovered that for a given sensor package size, other sensors (such as ultrasonic position sensors) may be more accurate than LVDTs and RVDTs. Therefore, by replacing an LVDT or RVDT with other types of position sensors, Applicants expect that the size and weight of the device may be reduced while also improving the accuracy of position sensing.

[0003] However, in some cases, the position sensed by a traditional LVDT or RVDT may be used by a full authority digital engine controller (FADEC) or electronic engine control unit (EECU). By design, the FADEC or EECU controls all aspects of engine performance. Therefore, the FADEC or EECU is configured to receive specific types of inputs associated with the LVDT or RVDT, specifically AC signals of a certain amplitude range and a certain frequency. Therefore, it is not possible to replace the traditionally used LVDT or RVDT with another type of sensor without modifying the FADEC or EECU. Due to the large number of operations managed by the FADEC or EECU, modifications to the FADEC or EECU must undergo a thorough performance and safety review before being adopted. Therefore, FADECs and EECUs are not usually modified, which means that the LVDT or RVDT must continue to be used, which also means that the advantages associated with other position sensor types cannot be realized. Summary of the invention

[0004] Embodiments of the present disclosure solve the above-mentioned problem of replacing an LVDT or RVDT with another position sensor type. Specifically, embodiments of the present disclosure relate to a system in which the position sensor type is made to emulate an LVDT or RVDT signal so that different position sensor types can be utilized without any modification to the FADEC or EECU. These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

[0005] Aspect 1 relates to a simulator circuit, the simulator circuit being configured to receive an AC excitation signal from a controller and a position signal from a position sensor connected to an effector. The position signal indicates the position of the effector. The simulator circuit includes a modulation device for modulating the amplitude and frequency of the position signal based on the AC excitation signal to generate a first AC response signal and a second AC response signal. The first AC response signal and the second AC response signal are configured to be used by the controller to determine the position of the effector.

[0006] Aspect 2 relates to the simulator circuit of aspect 1, wherein the modulation device includes a first analog amplitude modulator and a second analog amplitude modulator. The position signal includes a first position signal and a second position signal. The first position signal is an input to the first analog amplitude modulator, and the second position signal is an input to the second analog amplitude modulator. The AC excitation signal is an input to each of the first analog amplitude modulator and the second analog amplitude modulator, respectively. The first analog amplitude modulator multiplies the first position signal with the AC excitation signal to generate a first AC response signal, and the second analog amplitude modulator multiplies the second position signal with the AC excitation signal to generate a second AC response signal.

[0007] Aspect 3 relates to the emulator circuit of aspect 2, wherein the second position signal is inverted with respect to the first position signal.

[0008] Aspect 4 relates to the emulator circuit of aspect 2 or aspect 3, wherein the first analog amplitude modulator is included on a single integrated circuit and the second analog amplitude modulator is included on a single integrated circuit.

[0009] Aspect 5 relates to the emulator circuit of any one of aspects 2 to 4, wherein the first analog amplitude modulator and the second analog amplitude modulator are formed of high temperature transistors.

[0010] Aspect 6 relates to the emulator circuit described in any one of Aspects 2 to 5, wherein the first position signal is amplified or attenuated before being input to the first analog amplitude modulator, and the second position signal is amplified or attenuated before being input to the second analog amplitude modulator.

[0011] Aspect 7 relates to the emulator circuit according to any one of Aspects 2 to 5, wherein the modulation device includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), and a second digital-to-analog converter. The position signal is input to the digital signal processor, and the digital signal processor generates a first position signal and a second position signal based on the position signal, outputs the first position signal to the first digital-to-analog converter, and outputs the second position signal to the second digital-to-analog converter. The first digital-to-analog converter converts the first position signal into a first analog position signal and outputs the first analog position signal to the first analog amplitude modulator, and the second digital-to-analog converter converts the second position signal into a second analog position signal and outputs the second analog position signal to the second analog amplitude modulator.

[0012] Aspect 8 relates to the emulator circuit according to any one of Aspects 2 to 7, wherein the AC excitation signal is amplified before being input to the first analog amplitude modulator and the second analog amplitude modulator.

[0013] Aspect 9 relates to the emulator circuit according to any one of Aspects 2 to 8, wherein the AC excitation signal is phase-shifted by 180° before being input to the second analog amplitude modulator.

[0014] Aspect 10 relates to the emulator circuit of Aspect 1, wherein the modulation device includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), a second digital-to-analog converter, and an analog-to-digital converter (ADC). The analog-to-digital converter converts the AC excitation signal into a digital excitation signal and outputs the digital excitation signal to the digital signal processor. The position signal is input to the digital signal processor, and the digital signal processor generates a first digital position signal and a second digital position signal based on the position signal and the digital excitation signal, outputs the first digital position signal to the first digital-to-analog converter, and outputs the second digital position signal to the second digital-to-analog converter. The first digital-to-analog converter converts the first digital position signal into a first analog signal and outputs the first analog signal as a first AC response signal to the controller; and the second digital-to-analog converter converts the second digital position signal into a second analog signal and outputs the second analog signal as a second AC response signal to the controller.

[0015] Aspect 11 relates to the emulator circuit of Aspect 10, wherein the AC excitation signal is amplified before being input to the analog-to-digital converter.

[0016] Aspect 12 relates to the emulator circuit of Aspect 10 or Aspect 11, wherein the second digital position signal is inverted with respect to the first digital position signal.

[0017] Aspect 13 relates to a system. The system includes a controller configured to output an AC excitation signal and receive a first AC response signal and a second AC response signal. The controller is configured to determine the position of an effector based on the first AC response signal and the second AC response signal. The system also includes a position sensor configured to be connected to the effector. The position sensor is configured to output a position signal based on the position of the effector. The system also includes a simulator circuit configured to modulate the amplitude and frequency of the position signal based on the AC excitation signal to generate a first AC response signal and a second AC response signal. The simulator circuit is specifically the simulator circuit described in any one of Aspects 1 to 12.

[0018] Aspect 14 relates to the system according to aspect 13, wherein the controller includes a first terminal and a second terminal configured to generate an AC excitation signal. The simulator circuit includes a first impedance matching circuit configured to simulate a primary coil of a variable differential transformer, and the first impedance matching circuit is disposed between the first terminal and the second terminal.

[0019] Aspect 15 relates to the system according to aspect 13 or aspect 14, wherein the controller includes a third terminal, a fourth terminal and one or more ground terminals. The third terminal is configured to receive a first AC response signal, and the fourth terminal is configured to receive a second AC response signal. The simulator circuit includes a second impedance matching circuit configured to simulate a first secondary coil of a variable differential transformer, and the second impedance matching circuit is arranged between the third terminal and one or more ground terminals. The simulator circuit also includes a third impedance matching circuit configured to simulate a second secondary coil of a variable differential transformer, and the third impedance matching circuit is arranged between the fourth terminal and one or more ground terminals.

[0020] Aspect 16 relates to the system according to any one of aspects 13 to 15, further comprising a plurality of isolation transformers disposed between the emulator circuit and the controller.

[0021] Aspect 17 relates to a system according to any one of aspects 13 to 16, wherein the position sensor is an ultrasonic sensor, a Hall effect sensor, an eddy current sensor, a capacitive displacement sensor, an inductive sensor, a laser Doppler vibrometer, a photodiode array, a piezoelectric transducer, a position encoder, a potentiometer, an optical proximity sensor, or a string potentiometer.

[0022] Aspect 18 relates to a method. In the method, a first slave controller outputs an AC excitation signal to a simulator circuit. In the method, a second slave position sensor outputs a position signal to the simulator circuit. The position sensor is connected to an effector. In the method, the amplitude and frequency of the position signal are modulated to generate a first AC response signal and a second AC response signal. In the method, the first AC response signal and the second AC response signal are input to the controller, and in the method, the controller determines the position of the effector based on the first AC response signal and the second AC response signal.

[0023] Aspect 19 relates to the method of aspect 18, wherein the first output further comprises outputting the AC excitation signal to the first analog amplitude modulator and the second analog amplitude modulator. The second output further comprises outputting a position signal, the position signal comprising a first position signal and a second position signal. The first position signal is an input to the first analog amplitude modulator, and the second position signal is an input to the second analog amplitude modulator. Modulation further comprises multiplying the first position signal with the AC excitation signal at the first analog amplitude modulator to generate a first AC response signal, and multiplying the second position signal with the AC excitation signal at the second analog amplitude modulator to generate a second AC response signal.

[0024] Aspect 20 relates to the method of aspect 19, wherein the simulator circuit includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), and a second digital-to-analog converter. The second output also includes outputting the position signal to the digital signal processor. Modulating also includes generating a first position signal and a second position signal based on the position signal by the digital signal processor; outputting the first position signal to the first digital-to-analog converter and outputting the second position signal to the second digital-to-analog converter; converting the first position signal to a first analog position signal by the first digital-to-analog converter; converting the second position signal to a second analog position signal by the second digital-to-analog converter; and outputting the first analog position signal to a first analog amplitude modulator and outputting the second analog position signal to a second analog amplitude modulator.

[0025] Aspect 21 relates to the method of aspect 18, wherein the simulator circuit includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), a second digital-to-analog converter, and an analog-to-digital converter (ADC). The first output also includes converting the AC excitation signal into a digital excitation signal by the analog-to-digital converter, and outputting the digital excitation signal to the digital signal processor. The second output also includes outputting the position signal to the digital signal processor by the position sensor. Modulation also includes generating a first digital position signal and a second digital position signal based on the position signal and the digital excitation signal by the digital signal processor; outputting the first digital position signal to the first digital-to-analog converter, and outputting the second digital position signal to the second digital-to-analog converter; converting the first digital position signal into a first analog signal by the first digital-to-analog converter; and converting the second digital position signal into a second analog signal by the second digital-to-analog converter. The input also includes outputting the first analog signal as a first AC response signal to the controller by the first digital-to-analog converter and outputting the second analog signal as a second AC response signal to the controller by the second digital-to-analog converter.

[0026] Aspect 22 relates to the method according to any one of aspects 18 to 21, wherein the emulator circuit is isolated from the controller via a plurality of isolation transformers.

[0027] Other aspects, purposes and advantages of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0029] Figure 1 is a schematic diagram of a system including an analog variable differential transformer emulator circuit according to an exemplary embodiment;

[0030] Figure 2 is a schematic diagram of a system including a hybrid analog-digital variable differential transformer emulator circuit according to an exemplary embodiment;

[0031] Figure 3 is a schematic diagram of a system including a fully digital variable differential transformer emulator circuit according to an exemplary embodiment;

[0032] Figure 4 is a schematic diagram of a system including an analog variable differential transformer emulator circuit isolated from a controller using a transformer according to an exemplary embodiment;

[0033] FIG. 5A to FIG. 5Eis a diagram of an AC excitation signal, a position signal, a modulated position signal, an inverted position signal, a modulated inverted position signal, and a demodulated signal involved in determining a position by a controller according to an exemplary embodiment; and

[0034] Figure 6 A schematic diagram of a system configured to determine position based on modulation and demodulation of position sensor signals is shown in accordance with an exemplary embodiment.

[0035] While the present invention will be described in conjunction with certain preferred embodiments, it is not intended to be limited to these embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents included within the spirit and scope of the present invention as defined by the appended claims. DETAILED DESCRIPTION

[0036] LVDT and RVDT operate in essentially the same manner. Specifically, they both use a primary transformer coil that energizes two secondary transformer coils. A ferromagnetic core is connected to the effector, and the movement of the core relative to the two secondary coils (based on the position of the effector) produces a varying voltage between the two secondary coils. Therefore, the voltage difference between the secondary transformer coils can be used to determine the position of the core, and thus the position of the effector. The LVDT has a core connected to an effector that moves linearly, while the RVDT has a core connected to an effector that moves rotationally. Since the position of the core is determined using electrical principles associated with the transformer, the FADEC or EECU outputs an AC excitation signal for the primary transformer coil, and the FADEC or EECU is configured to receive an AC response signal from the two secondary transformer coils. Sensors that do not operate using a transformer do not utilize an AC excitation signal or generate two corresponding AC response signals. In addition, the FADEC or EECU will not be able to parse sensor data received from a non-transformer position sensor.

[0037] According to embodiments of the present disclosure, various circuit configurations are provided to simulate an LVDT or RVDT (hereinafter collectively referred to as a "VDT") response signal using an excitation signal from a FADEC or EECU (hereinafter collectively referred to as a "controller"). As will be discussed in more detail below, the sensor output is amplitude modulated using the excitation signal generated by the controller. The modulation can be accomplished using analog components or digital components (including using software). In addition, the system configuration includes an impedance matching circuit so that a built-in test circuit operated by the controller can sense the VDT connected to the controller. These and other aspects and advantages will be described in more detail below in conjunction with the accompanying drawings. The embodiments presented herein are for illustration only and are not intended to be limiting.

[0038] Figure 1An embodiment of a system including a simulation circuit 100 having a means for simulating a VDT signal from a position sensor 102 is shown. In the system, the simulator circuit 100 communicates with a controller 104, which is configured to generate an AC excitation signal from a first terminal 106 and a second terminal 108. In one or more embodiments, an impedance matching circuit 110 is disposed between the first terminal 106 and the second terminal 108. In this way, the built-in test circuit of the controller 104 senses the impedance associated with the connected VDT. Since the controller 104 still senses the VDT, the controller 104 does not report an error, which may prevent the operation of the system controlled by the controller 104. In one or more embodiments, a first amplifier 112 is used to amplify or attenuate the AC excitation signal.

[0039] exist Figure 1 In the configuration of the analog simulator circuit 100 shown, the AC excitation signal is an input to the first amplitude modulator 114 and the second amplitude modulator 116. In one or more embodiments, the AC excitation signal of the second amplitude modulator 116 is inverted by the 180° phase shift circuit 118. The first amplitude modulator 114 and the second amplitude modulator 116 each also receive an input from the position sensor 102. In one or more embodiments, the position sensor 102 outputs a position signal to the first amplitude modulator 114 and the second amplitude modulator 116. In one or more embodiments, the first amplitude modulator 114 receives the position signal, and the second amplitude modulator 116 receives the inverted position signal. The position signal from the position sensor 102 is multiplied by the excitation signal at the first amplitude modulator 114 and the second amplitude modulator 116, respectively. In many cases, the output signal of the position sensor will be an analog signal that varies in proportion to the position sensed by the position sensor 102, and the signal may not be a sine wave and may be close to a DC signal. By multiplying the output signal of the position sensor 102 with the excitation signal, the first amplitude modulator 114 and the second amplitude modulator 116 generate and output corresponding AC signals, simulating AC response signals related to the response signals from the two secondary coils of the VDT.

[0040] In one or more embodiments, the position signal from the position sensor 102 is amplified or attenuated. In one or more embodiments, including Figure 1In the illustrated embodiment, the first position signal from the position sensor 102 is amplified or attenuated on the second amplifier 120, and the second position signal (which may be an inverted signal as described above) is amplified or attenuated on the third amplifier 122. In more than one embodiment, the third amplifier 122 inverts the position signal from the position sensor 102 (i.e., the third amplifier 122 is an inverting amplifier). In more than one embodiment, the amplified or attenuated first position signal is an input to the first amplitude modulator 114, and the amplified or attenuated second position signal is an input to the second amplitude modulator 116.

[0041] The controller 104 has a third terminal 124 configured to receive the output of the first amplitude modulator 114 and a fourth terminal 126 configured to receive the output of the second amplitude modulator 116. In more than one embodiment, including the illustrated embodiment, the controller 104 further includes a fifth terminal 128 that is grounded (which may correspond to the center tap connection between the secondary coils of the VDT). However, in more than one other embodiment, the controller 104 includes a sixth terminal that is also grounded (e.g., for a six-wire VDT). Thus, the controller 102 receives two AC response signals that simulate the output of the VDT secondary coil.

[0042] Figure 2 An embodiment of a system including a digital circuit 200 is shown, the digital circuit having means for simulating a VDT based on the position sensor 102. The circuit 200 is at least partially digital in that the output of the position sensor 102 is processed in a digital signal processor (DSP) 230. The DSP 230 outputs a first position signal and a second position signal that may be inverted with respect to the first position signal. The first position signal is input to a first digital-to-analog converter (DAC) 232, and the second position signal is input to a second DAC 234. The DACs 232, 234 convert the digital processing signals from the DSP 230 into analog signals. The analog signals from the DACs 232, 234 are input to the amplitude modulators 114, 116, where they are multiplied by the AC excitation signal from the controller 104. Thus, the analog signals from the DACs 232, 234 will be within the appropriate range expected by the controller 102 based on the amplitude and frequency of the AC excitation signal.

[0043] In one or more embodiments, the first amplitude modulator 114 and the second amplitude modulator 116 are commercially available products. For example, the amplitude modulator can be a single integrated circuit, such as the AD630 or AD534 from Analog Devices, Inc. of Norwood, Massachusetts. In one or more other embodiments, the modulator is formed by transistors, such as, among other possibilities, bipolar junction transistors (BJTs), metal oxide semiconductor field effect transistors (MOSFETs), junction field effect transistors (JFETs), or bipolar MOSFETs (BiFETs). For example, gallium nitride BJTs can be used for high temperature applications. For example, high temperature BJTs can be used in Gilbert cell multiplier circuits.

[0044] Figure 3 An embodiment of a system including an emulator circuit 300 is shown, wherein the response signal is synthesized entirely in digital form. In one or more embodiments, the AC excitation signal from the controller 104 is converted to a digital signal using an analog-to-digital converter (ADC) 336. The digital signal output from the ADC 336 is input to the DSP 230. The DSP 230 also receives an output from the position sensor 102. In the DSP 230, software or digital logic uses the digital excitation signal and the output signal from the position sensor 102 to generate a first position signal and a second position signal that may be inverted with the first position signal at a desired amplitude and frequency. The first position signal is converted to an analog signal by a first DAC 232, and the second position signal is converted to an analog signal by a second DAC 234. In one or more embodiments, the position signals from the DACs 232, 234 are directly input to the third terminal 124 and the fourth terminal 126 of the controller 104, and in particular, no modulator circuits (such as amplitude modulators 114, 116) are required.

[0045] Figure 4 Another embodiment of a system including an emulator circuit 400 having means for emulating a VDT that physically and electrically isolates the emulator circuit 400 from the controller 104 is shown. Figure 4 Shown with Figure 1 The embodiment of the simulator circuit 100 shown is substantially similar to the simulator circuit 400. That is, the simulator circuit includes an AC excitation signal fed as a first input to first and second amplitude modulators 114, 116, and first and second position signals from the position sensor 102 fed as second inputs to respective first and second amplitude modulators 114, 116. The first and second amplitude modulators 114, 116 output respective AC response signals for the controller 104.

[0046] However, in Figure 4In the illustrated embodiment, the first terminal 106 and the second terminal 108 are connected to the first coil 438 of the first isolation transformer 440. The second coil 442 of the first isolation transformer 440 is connected to the impedance matching circuit 110 and the inputs of the first and second amplitude modulators 114, 116. The second isolation transformer 444 includes a first coil 446 located between the third terminal 124 of the controller 104 and the fifth terminal 128 of the controller 104. The second coil 448 of the second isolation transformer 444 is connected between ground and the output of the first amplitude modulator 114. In this way, the second isolation transformer 444 transmits the first AC response signal to the controller 104 while being physically and electrically isolated from the controller 104. The third isolation transformer 450 includes a first coil 452 between the fourth terminal 126 and the fifth terminal 128 (or the sixth terminal, if provided) of the controller 104. The second coil 454 of the third isolation transformer 450 is connected between ground and the output of the second amplitude modulator 116. In this way, the third isolation transformer 450 transmits the second AC response signal to the controller 104 while being physically and electrically isolated from the controller 104 .

[0047] although Figure 4 The outputs of the amplitude modulators 114, 116 are shown connected to the second coils 448, 454 of the second and third isolation transformers 444, 450, but the second coils 448, 454 of the second and third isolation transformers 444, 450 may also be connected to the DACs 232, 234, as shown. Figure 2 and Figure 3 In addition, although Figure 4 The second coil 442 of the first isolation transformer 440 is shown connected as the input of the amplitude modulator 114, 116, but the second coil 442 of the first isolation transformer 440 can also be connected to the ADC 336, such as Figure 3 shown.

[0048] Figure 4 Also shown is a second impedance matching circuit 456 connected between the output of the first amplitude modulator 114 and ground and a third impedance matching circuit 458 connected between the output of the second amplitude modulator 116 and ground. The second and third impedance matching circuits 456, 458 reflect and emulate the impedance of the secondary transformer coil of a conventional VDT so that the built-in test circuit of the controller 104 detects an appropriate response from the emulator circuit. In one or more embodiments, such impedance matching circuits 456, 458 are also included in Figures 1 to 3 The simulator circuit is shown.

[0049] Figures 1 to 4Also shown is each emulator circuit 100, 200, 300, 400, which includes an EMI / TVS circuit 460 to protect the controller 104 from electromagnetic interference and transient voltage spikes. Figure 4 As shown, the controller 104 can also provide power to the position sensor 102 , for example, using a 28V DC power supply.

[0050] As described above, the emulator circuit disclosed herein is designed to mimic the output of a VDT (linear or rotary) so that the controller 104 operates normally (i.e., without redesigning the controller 104). This allows a variety of position sensors to be controlled by a standard controller 104. In particular, the emulator circuit can be configured to work with all forms of standard position sensing devices that provide analog voltage or frequency outputs. In one or more embodiments, the position sensor is (among other possibilities) an ultrasonic sensor (such as, among other possibilities, an ultrasonic position sensor disclosed in U.S. Application No. 16 / 987,828, filed on August 7, 2020, the entire contents of which are incorporated herein by reference in their entirety), a Hall effect sensor, an eddy current sensor, a capacitive displacement sensor, an inductive sensor, a laser Doppler vibrometer, a photodiode array, a piezoelectric transducer, a position encoder, a potentiometer, an optical proximity sensor, or a string potentiometer, among others.

[0051] Ultrasonic sensors of the type disclosed in the '828 application are particularly suitable for use in systems having the disclosed simulator circuits 100, 200, 300, and 400. Such ultrasonic sensors include transceivers located on either side of a movable body within a fluid chamber, and the ultrasonic transceivers bounce ultrasonic signals off the movable body as the movable body translates within the fluid chamber. Based on the time taken for the ultrasonic signals to reach the movable body and bounce back to the respective ultrasonic transceivers, the position of the movable body can be determined. Specifically, the position is related to (t 1 -t 2 ) / (t 1 +t 2 ) is proportional to, where t 1 is the time required from the first ultrasonic transceiver transmitting the ultrasonic signal to the ultrasonic signal bouncing off the movable body and returning to the first ultrasonic transceiver, and t 2 is the time required from the second ultrasonic transceiver transmitting the ultrasonic signal to the ultrasonic signal bouncing off the movable body and returning to the second ultrasonic transceiver. Advantageously, (t 1 -t 2 ) / (t 1 +t 2 ) is related to the (VI-V2) / (V1+V2) ratio reading obtained from the VDT, with the same advantages of being unaffected by DC offset and common-mode amplitude variations.

[0052] FIG. 5A to FIG. 5E Signals involved in determining a position based on a position signal of a position sensor are shown. Figure 5A A diagram showing an AC excitation signal generated by a controller. Figure 5B The position sensor signal is shown as a dashed line. This signal is Figure 5A The AC excitation signal shown is modulated to generate Figure 5B The modulated signal is shown as the solid line in the figure. As mentioned above, the position signal can be modulated using analog or digital components. In either case, the output is a voltage signal, shown as V a .like Figure 5C As shown, the position signal is also inverted. Specifically, Figure 5C The dotted line in the figure represents the inverted position signal. The inverted position signal is modulated based on the AC excitation signal to generate Figure 5C The modulation signal V shown by the solid line b Like other signals, the inverted position signal can be modulated using analog or digital components, and the output is also a voltage signal, shown as V b . Figure 5D shows a modulation signal (V a 、V b These signals are provided to the controller, which demodulates the signals using internal logic or programming to provide a demodulated signal (V a -V b ) / (V a +V b ),like Figure 5E This is the same calculation that the controller performs when it receives a voltage signal from a VDT, so a controller configured to determine position based on a VDT input can be used to determine position based on a non-VDT input.

[0053] As described above, various embodiments of emulator circuits are provided that utilize an AC excitation signal and generate a response signal in a manner that mimics a VDT. In this way, the controller can operate with virtually any position sensor without reconfiguration or modification that would require extensive testing and qualification before it is approved for use in an actual application. Thus, the emulator circuits disclosed herein allow for replacement of VDT sensors, thereby improving accuracy and reducing sensor size without requiring costly and time-consuming changes to the controller.

[0054] Figure 6An embodiment of a sensor system 500 for improving the accuracy of a sensor 102 in a noisy environment is shown. In various cases, a controller 104 receives sensor inputs (e.g., fuel temperature, fuel level, fuel pressure, etc.) to control an engine. The sensor 102 may be, for example, a thermocouple, a pressure sensor, a potentiometer, or a Hall effect sensor, etc. These sensors typically provide an analog signal that the controller 104 uses to control the engine. However, the accuracy of the signal can be improved, particularly by filtering out noise, by modulating the signal and then demodulating the signal in the controller.

[0055] like Figure 6 As shown, the sensor system 500 includes a DSP 230 that receives a sensor signal from the sensor 102. In the DSP 230, software or logic modulates the sensor signal using an AC signal generated by the DSP 230. That is, the sensor signal is not modulated using an AC excitation signal generated by the controller 104 (because an AC excitation signal is not required in the absence of a VDT). The DSP 230 outputs the modulated sensor signal to a first DAC 232, which converts the modulated digital sensor signal into a first analog signal for input to the controller 104. The DSP 230 also inverts the sensor signal and modulates the inverted sensor signal using the generated AC signal. The DSP outputs the modulated inverted sensor signal to a second DAC 234, which converts the modulated digital inverted sensor signal into a second analog signal for input to the controller 104. In the controller 104, the analog signal is demodulated and the sensor output is determined.

[0056] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0057] In the context of describing the present invention (especially in the context of the following claims), the use of the terms "a", "an" and "said" and similar referents should be interpreted as covering the singular and plural, unless otherwise specified herein or clearly contradicted by the context. Unless otherwise specified, the terms "include", "have", "include" and "contain" should be interpreted as open terms (i.e., "including but not limited to"). Unless otherwise specified herein, the numerical ranges listed herein are merely intended to be a convenient method of individually referring to each individual value falling within the range, and each individual value is incorporated into the specification as if it were recorded separately herein. Unless otherwise specified herein or clearly contradicted by the context, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the present invention and does not limit the scope of the present invention, unless otherwise stated. Any language in the specification should not be interpreted as indicating that any unclaimed element is essential to the practice of the present invention.

[0058] Preferred embodiments of the present invention are described herein, including the best mode of implementing the present invention known to the inventor. For those of ordinary skill in the art, after reading the above description, variations of these preferred embodiments will become apparent. The inventor expects that those skilled in the art will be able to adopt such variations as appropriate, and the inventor intends to implement the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter described in the appended claims as permitted by applicable law. In addition, unless otherwise stated herein or clearly contradictory to the context, the present invention covers any combination of the above elements in all possible variations thereof.

Claims

1. A simulator circuit configured to receive an AC excitation signal from a controller and a position signal from a position sensor connected to an effector, wherein the position signal indicates a position of the effector, wherein the simulator circuit include: A modulation device, for modulating the amplitude and frequency of the position signal based on the AC excitation signal to generate a first AC response signal and a second AC response signal; Wherein, the position of the effector can be determined by the controller based on the first AC response signal and the second AC response signal.

2. The emulator circuit according to claim 1, in, The modulation device includes a first analog amplitude modulator and a second analog amplitude modulator, wherein the position signal includes a first position signal and a second position signal, wherein the first position signal is an input to the first analog amplitude modulator and the second position signal is an input to the second analog amplitude modulator, wherein the AC excitation signal is an input to each of the first analog amplitude modulator and the second analog amplitude modulator, and wherein the first analog amplitude modulator multiplies the first position signal with the AC excitation signal to generate the first AC response signal, and the second analog amplitude modulator multiplies the second position signal with the AC excitation signal to generate the second AC response signal.

3. The emulator circuit according to claim 2, in, The second position signal is in antiphase with respect to the first position signal.

4. The emulator circuit according to claim 2 or claim 3, in, The first analog amplitude modulator is contained on a single integrated circuit and the second analog amplitude modulator is contained on a single integrated circuit.

5. The emulator circuit according to any one of claims 2 to 4, in, The first analog amplitude modulator and the second analog amplitude modulator are formed of high temperature transistors.

6. The emulator circuit according to any one of claims 2 to 5, in, The first position signal is amplified or attenuated before being input to the first analog amplitude modulator, and the second position signal is amplified or attenuated before being input to the second analog amplitude modulator.

7. The emulator circuit according to any one of claims 2 to 5, in, The modulation device includes a digital signal processor (DSP), a first digital-to-analog converter (DAC) and a second digital-to-analog converter, wherein the position signal is input to the digital signal processor, wherein the digital signal processor generates the first position signal and the second position signal based on the position signal, and outputs the first position signal to the first digital-to-analog converter, and outputs the second position signal to the second digital-to-analog converter, wherein the first digital-to-analog converter converts the first position signal into a first analog position signal and outputs the first analog position signal to the first analog amplitude modulator, and wherein the second digital-to-analog converter converts the second position signal into a second analog position signal and outputs the second analog position signal to the second analog amplitude modulator.

8. The emulator circuit according to any one of claims 2 to 7, in, The AC excitation signal is amplified before being input to the first analog amplitude modulator and the second analog amplitude modulator.

9. The emulator circuit according to any one of claims 2 to 8, in, The AC excitation signal is phase-shifted by 180° before being input to the second analog amplitude modulator.

10. The emulator circuit according to claim 1, in, The modulation device includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), a second digital-to-analog converter and an analog-to-digital converter (ADC), wherein the analog-to-digital converter converts the AC excitation signal into a digital excitation signal and outputs the digital excitation signal to the digital signal processor, wherein the position signal is input to the digital signal processor, wherein the digital signal processor generates a first digital position signal and a second digital position signal based on the position signal and the digital excitation signal, and outputs the first digital position signal to the first digital-to-analog converter, and outputs the second digital position signal to the second digital-to-analog converter, wherein the first digital-to-analog converter converts the first digital position signal into a first analog signal and outputs the first analog signal as the first AC response signal to the controller, and wherein the second digital-to-analog converter converts the second digital position signal into a second analog signal and outputs the second analog signal as the second AC response signal to the controller.

11. The emulator circuit according to claim 10, in, The AC excitation signal is amplified before being input to the analog-to-digital converter.

12. The emulator circuit according to claim 10 or claim 11, in, The second digital position signal is inverted with respect to the first digital position signal.

13. A system, include: a controller configured to output an AC excitation signal and receive a first AC response signal and a second AC response signal, the controller configured to determine a position of the effector based on the first AC response signal and the second AC response signal; a position sensor configured to be coupled to the effector, the position sensor configured to output a position signal based on the position of the effector; as well as A simulator circuit configured to modulate the amplitude and frequency of the position signal based on the AC excitation signal to generate the first AC response signal and the second AC response signal, in particular the simulator circuit according to any one of claims 1 to 12.

14. The system according to claim 13, in, The controller includes a first terminal and a second terminal configured to generate the AC excitation signal, and wherein the emulator circuit includes a first impedance matching circuit configured to emulate a primary coil of a variable differential transformer, wherein the first impedance matching circuit is disposed between the first terminal and the second terminal.

15. A system according to claim 13 or claim 14, in, The controller includes a third terminal, a fourth terminal and one or more ground terminals, wherein the third terminal is configured to receive the first AC response signal, wherein the fourth terminal is configured to receive the second AC response signal, wherein the emulator circuit includes a second impedance matching circuit configured to emulate a first secondary coil of a variable differential transformer, wherein the second impedance matching circuit is arranged between the third terminal and the one or more ground terminals, and wherein the emulator circuit includes a third impedance matching circuit configured to emulate a second secondary coil of the variable differential transformer, and wherein the third impedance matching circuit is arranged between the fourth terminal and the one or more ground terminals.

16. The system of any one of claims 13 to 15, comprising a plurality of isolation transformers disposed between the emulator circuit and the controller.

17. A system according to any one of claims 13 to 16, in, The position sensor is an ultrasonic sensor, a Hall effect sensor, an eddy current sensor, a capacitive displacement sensor, an inductive sensor, a laser Doppler vibrometer, a photodiode array, a piezoelectric transducer, a position encoder, a potentiometer, an optical proximity sensor or a string potentiometer.

18. A method, include: First output: outputting the AC excitation signal from the controller to the simulator circuit; A second output: outputting a position signal from a position sensor to the simulator circuit, the position sensor being connected to the effector; modulating the amplitude and frequency of the position signal to generate a first AC response signal and a second AC response signal; inputting the first AC response signal and the second AC response signal into the controller; The position of the effector is determined by the controller based on the first AC response signal and the second AC response signal.

19. The method according to claim 18, in, The first output also includes outputting the AC excitation signal to a first analog amplitude modulator and a second analog amplitude modulator; Wherein, the second output also includes outputting the position signal, and the position signal includes a first position signal and a second position signal; wherein the first position signal is an input to the first analog amplitude modulator and the second position signal is an input to the second analog amplitude modulator; and The modulation further comprises multiplying the first position signal with the AC excitation signal at the first analog amplitude modulator to generate the first AC response signal, and multiplying the second position signal with the AC excitation signal at the second analog amplitude modulator to generate the second AC response signal.

20. The method according to claim 19, in, The emulator circuit includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), and a second digital-to-analog converter; Wherein, the second output also includes outputting the position signal to the digital signal processor; Among them, modulation also includes: generating, by the digital signal processor, the first position signal and the second position signal based on the position signal; Outputting the first position signal to the first digital-to-analog converter, and outputting the second position signal to the second digital-to-analog converter; Converting the first position signal into a first analog position signal by the first digital-to-analog converter; converting the second position signal into a second analog position signal by the second digital-to-analog converter; and The first analog position signal is output to the first analog amplitude modulator, and the second analog position signal is output to the second analog amplitude modulator.

21. The method according to claim 18, in, The simulator circuit includes a digital signal processor (DSP), a first digital-to-analog converter (DAC), a second digital-to-analog converter, and an analog-to-digital converter (ADC); Wherein, the first output also includes converting the AC excitation signal into a digital excitation signal by the analog-to-digital converter and outputting the digital excitation signal to the digital signal processor; Wherein, the second output also includes the position sensor outputting the position signal to the digital signal processor; Among them, modulation also includes: generating, by the digital signal processor, a first digital position signal and a second digital position signal based on the position signal and the digital excitation signal; outputting the first digital position signal to the first digital-to-analog converter and outputting the second digital position signal to the second digital-to-analog converter; converting the first digital position signal into a first analog signal by the first digital-to-analog converter; and converting the second digital position signal into a second analog signal by the second digital-to-analog converter; The input also includes: The first analog signal is outputted by the first digital-to-analog converter to the controller as the first AC response signal; and The second analog signal is outputted by the second digital-to-analog converter to the controller as the second AC response signal.

22. The method of any one of claims 18 to 21, further comprising isolating the emulator circuit from the controller via a plurality of isolation transformers.

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