A Marine Thrust and Torque Comprehensive Monitoring Device and Method

Abstract

The present invention relates to a marine thrust and torque comprehensive monitoring device and method. The two-dimensional optical measurement arm of the device consists of two measurement arms that can move relative to each other. One measurement arm is equipped with a laser emitter, and the other measurement arm is equipped with a four-quadrant detector. Both measurement arms are installed on a marine bearing through snap rings. The light source emitted by the laser emitter directly irradiates the center position of the four-quadrant detector, and the optical axis direction is orthogonal to the axial direction of the bearing. By converting the off-plane orthogonal components into in-plane orthogonal components of the four-quadrant detector. When thrust and torque are generated, the light spot generates a relative displacement on the four-quadrant detector, enabling simultaneous measurement of thrust and torque. The monitoring method of the marine thrust and torque comprehensive monitoring device of the present invention converts the shafting thrust and torque into the displacement of the optical measurement arm, accurately measures the displacement change through a four-quadrant photosensitive detector, and obtains an accurate measurement result after calibration.

Description

Technical Field

[0001] The present invention relates to a thrust and torque monitoring system for a ship shafting, and particularly to a marine thrust and torque integrated monitoring device and method, belonging to the field of ship testing. Background Art

[0002] The thrust and torque of a ship shafting are key parameters of ship power. The measured data is of great value for the safe use of the main engine, the monitoring and design optimization of the propeller efficiency, and the navigation state management. The actual ship shafting thrust and torque deformation amounts vary greatly and are mutually coupled, and at the same time, the measurement is difficult.

[0003] A thrust and torque measuring device for pod test disclosed in Chinese Patent Publication No. CN104634494A obtains the thrust and torque data generated by the spiral tube by installing a thrust and torque sensor between the motor and the propeller in the pod. This method uses a mature thrust and torque sensor on the market, which needs to be installed during the device design. However, currently, this type of intrusive sensor is basically not installed in the actual ship shafting, and reinstalling it will change the original technical state of the shafting design. Therefore, this type of intrusive thrust and torque integrated monitoring device is not suitable for the monitoring of existing ships.

[0004] Currently, the non-intrusive thrust and torque integrated monitoring method mainly obtains the shafting torsion and compression deformation by pasting strain gauges. The measurement accuracy is affected by the pasting effect of the strain gauges, with low accuracy. The error generally reaches 5% or even worse, and the repeatability is poor. The measurement results are difficult to play the expected role. More importantly, the strain gauge is a one-time measurement device. Once pasted and used, it cannot be disassembled. The monitoring devices that measure thrust and torque by directly pasting strain gauges cannot perform full-system calibration of the measurement element, signal processing device, and display device. The accuracy of the measurement results cannot be guaranteed by the quantity transfer system. Therefore, in engineering, it can only be used for temporary measurement and qualitative analysis and is difficult to play a key role.

[0005] Another strain-type non-invasive method is to arrange two snap rings on the shaft at a certain distance, and an elastomer with a strain gauge pasted thereon is installed between the snap rings. The thrust deformation and torsional deformation of the shafting are converted into the strain of the elastomer through the snap rings, and then the thrust and torque data of the shafting are obtained. This monitoring device is convenient to disassemble and assemble, can be calibrated with a high-precision press and torque machine in the laboratory, and can ensure measurement accuracy. However, there are two problems with this method. First, there is a coupling relationship between thrust and torque on the shaft itself. After being transmitted to the elastomer through the snap ring, this coupling relationship becomes more complex and difficult to eliminate. When the shafting has both thrust and torque, the measured data is difficult to reflect the true state, and the data accuracy in actual use is poor. Second, the range of the strain gauge itself is relatively large, reaching more than 10,000 με. The rated torque strain of the ship shafting is generally 1,000 με, and the rated thrust strain is only about 20 με, and some ships are even lower than 10 με, which is already near the measurement lower limit of the strain gauge. At this time, the linearity and repeatability of the strain gauge measurement results are relatively low, and the accuracy of the measured data in actual application cannot meet the monitoring requirements. Summary of the Invention

[0006] The present invention aims to provide a comprehensive marine thrust and torque monitoring device and method. Through this monitoring device and method, the shafting deformation can be transmitted to the two-dimensional optical sensor on the measuring arm, and accurate thrust and torque data can be obtained through the decoupling of the sensor signals, solving the problems of poor accuracy and non-traceability of traditional strain-type monitoring devices, and providing effective support for the scientific management and design optimization of ships.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0008] A comprehensive marine thrust and torque monitoring device includes a power supply module, a rotor acquisition module, a snap ring, a two-dimensional optical measuring arm, a stator bracket, a power supply module beside the shaft, an acquisition instrument, and a host computer installed on a rotating shaft. The two-dimensional optical measuring arm is composed of two measuring arms that can move relative to each other. One measuring arm is equipped with a laser emitter, and the other measuring arm is equipped with a four-quadrant detector. Both measuring arms are installed on a marine bearing through snap rings. The light source emitted by the laser emitter directly irradiates the center position of the four-quadrant detector, and the optical axis direction is orthogonal to the axial direction of the bearing. By converting the off-plane orthogonal components into in-plane orthogonal components of the four-quadrant detector; when thrust and torque are generated, the light spot generates a relative displacement on the four-quadrant detector, and the thrust and torque can be measured simultaneously.

[0009] Furthermore, the four-quadrant detector is composed of photoelectric converters symmetrically distributed in the four quadrants of the rectangular coordinate system and having similar performance to form a torque and thrust optical sensor.

[0010] Further, the optoelectronic sensor chip in the torque thrust optical sensor adopts a quadrupole optoelectronic diode array, with a 7-pin connector, having a current-to-voltage amplifier. The provided sum signal is the sum of the signals of all four quadrant diodes, and the provided difference signal is the difference in the light intensities sensed by the paired optoelectronic diode elements in the array.

[0011] Further, the signal processing circuit in the marine thrust torque comprehensive monitoring device includes a rotor part and a stator part. The rotor part uses operational amplifiers to build a conditioning circuit for the electrical signals of 12 channels transmitted by four optical measurement arms, including a voltage conversion circuit and a low-pass filter circuit that convert the voltage signal into a voltage input range suitable for the ADC chip. The ADC converts the input analog signal into a digital signal and transmits it to the lower computer SoC chip through SPI for acquisition. The lower computer inputs the collected signal into a buffer after averaging and sampling filtering a certain number of times to reduce the sampling error. The stator part communicates with the rotor part through a 2.4G WIFI module, and transmits all the signals of all channels filtered by the rotor part to the SoC chip of the stator part. The SoC of the stator part also has a zero adjustment and function self-check module, and displays the signal through an LCD or sends the data to the upper computer through Ethernet for the upper computer to analyze and process the data.

[0012] A marine thrust torque comprehensive monitoring method uses a marine thrust torque comprehensive monitoring device, which specifically includes the following steps:

[0013] Step 1: Two snap rings are installed on the cross-sections of the shaft section spaced by ΔL, and 4 two-dimensional optical measurement arms are evenly arranged circumferentially between the snap rings;

[0014] Step 2: When there are torque and thrust in the shafting, the position of the laser spot emitted by the laser emitter on the four-quadrant photosensitive detector will change (Δx, Δy), and the output voltages V1, V2, V3, and V4 of the optoelectronic converters in the four quadrants will also change accordingly;

[0015] Step 3: The three groups of voltage signals output by the quadrupole optoelectronic diode array are respectively:

[0016] P2 = (V2 + V3) - (V1 + V4)

[0017] P3 = (V1 + V2) - (V3 + V4)

[0018] P4 = V1 + V2 + V3 + V4

[0019] Where: P2 is the electrical signal generated by the bottom quadrants D2 and D3 of the photodiode minus the voltage signal of the top quadrants D1 and D4; P3 is the electrical signal generated by the quadrants D1 and D2 of the photodiode minus the voltage signal generated by the quadrants D3 and D4; P4 is the sum of the voltage signals generated by the four quadrants D1, D2, D3, and D4 of the photodiode;

[0020] Then the calculation formula for the relative displacement (Δx, Δy) of the laser spot on the four-quadrant sensor is:

[0021]

[0022] Δx and Δy respectively correspond to the offsets of the spot center in the x and y directions of the four-quadrant sensor. Sending the three voltage signals P2, P3, and P4 to the signal processing unit with an ADC can perform real-time measurement of the thrust and torsion in the x and y directions;

[0023] Step 4: The shaft torque M and thrust T are calculated from the change in the position of the laser spot (Δx, Δy). The specific formula is:

[0024]

[0025]

[0026] Where, E is the elastic modulus, A is the cross-sectional area of the shaft before deformation, G is the shear modulus, I p is the moment of inertia, and ΔL is the distance between the snap rings, all of which are constants. Then the thrust system k T and the torque coefficient k M are constants and are obtained through laboratory calibration.

[0027] The beneficial effects of the present invention are:

[0028] The present invention proposes a marine thrust and torque comprehensive monitoring device, which converts the shaft thrust and torque into the displacement of the optical measurement arm, accurately measures the displacement change through a four-quadrant photosensitive detector, and obtains accurate measurement results after calibration.

[0029] (1) The present invention proposes a two-dimensional optical measurement method, which adopts the four-quadrant differential measurement principle to simultaneously obtain the shaft thrust and the two-dimensional displacement change of the optical measurement arm caused by the thrust. The measurement accuracy is higher than that of the general strain gauge measurement method;

[0030] (2) The displacements generated by the thrust and torque in the optical sensor of the present invention are orthogonal, effectively reducing the mutual influence between the two and further improving the measurement accuracy;

[0031] (3) The design method of the snap ring type thrust torque monitoring device of the present invention, the device is detachable and reusable, which provides an effective technical means for the calibration of the monitoring device and facilitates the long-term reliable use of the monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the marine thrust torque comprehensive monitoring device of the present invention;

[0033] Figure 2 Schematic diagram of the two-section structure of the two-dimensional optical measurement arm;

[0034] Figure 3 Schematic diagram of the four-quadrant photosensitive detector;

[0035] Figure 4 Signal processing circuit of the four-quadrant photosensitive detector;

[0036] Figure 5 Overall block diagram of the signal processing circuit. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described below in conjunction with the drawings and embodiments.

[0038] As Figure 1 shown, a marine thrust torque comprehensive monitoring device of the present invention includes a power supply module 2, a rotor acquisition module 3, a snap ring 4, a two-dimensional optical measurement arm 5, a stator bracket 6, a power supply module beside the shaft 7, an acquisition instrument 8 and a host computer 9 installed on a rotating shaft 1. The two-dimensional optical measurement arm 5 is composed of two measurement arms that can move relatively. A laser emitter is installed in one measurement arm, and a four-quadrant detector is installed in the other measurement arm; both measurement arms are installed on a marine bearing through a snap ring 4. The light source emitted by the laser emitter directly irradiates the center position of the four-quadrant detector, and the optical axis direction is orthogonal to the axial direction of the bearing. By converting the off-plane orthogonal components into in-plane orthogonal components of the four-quadrant detector; when thrust and torque are generated, the light spot will generate a relative displacement on the four-quadrant detector, and the thrust and torque can be measured simultaneously.

[0039] As Figure 2 shown, the two-dimensional optical measurement arm 5 is of a two-section structure and is respectively fixed on the end face of the snap ring 4. A laser emitter LD and a four-quadrant photosensitive detector QP are respectively installed at the adjacent positions of the two sections. As Figure 3 shown, the four-quadrant detector QP is composed of photoelectric converters symmetrically distributed in four quadrants of a rectangular coordinate system and having similar performance. When there are torque and thrust in the shafting, the position of the laser spot emitted by the laser emitter on the four-quadrant photosensitive detector will change (Δx, Δy), and the voltages (V1, V2, V3, V4) emitted by the photoelectric converters in the four quadrants will also change accordingly.

[0040] According to the working principle of the four-quadrant photoelectric sensor, the specific implementation is as Figure 4 shown in the circuit. When the laser source irradiates the four-quadrant detector, the four-quadrant detector converts light energy into voltage, and then gives the offset of the light spot centroid relative to the center of the four quadrants through four arithmetic operations. This offset is sent to the analog-to-digital converter (ADC) in the form of an analog voltage.

[0041] In the torque thrust optical sensor of the present invention, the photoelectric sensor chip uses a four-pole photodiode array, with a 7-pin connector, having a current-to-voltage amplifier. The provided sum signal is the sum of all four quadrant diode signals, and the provided difference signal is the difference in light intensity sensed by paired photodiode elements in the array. The three groups of voltage signals output by the four-pole photodiode array are respectively:

[0042] P2 = (V2 + V3) - (V1 + V4)

[0043] P3 = (V1 + V2) - (V3 + V4)

[0044] P4 = V1 + V2 + V3 + V4

[0045] Where: P2 is the electrical signal generated by the bottom quadrants D2 and D3 of the photodiode minus the electrical signals of the top quadrants D1 and D4; P3 is the electrical signal generated by the photodiode quadrants D1 and D2 minus the electrical signals generated by the quadrants D3 and D4; P4 is the sum of the electrical signals generated by the four quadrants D1, D2, D3, and D4 of the photodiode.

[0046] Then the calculation formula for the relative displacement (Δx, Δy) of the laser spot on the four-quadrant sensor is:

[0047]

[0048] The signal processing circuit is as Figure 5 shown. The three output signals X, Y, and Z of the measuring arm respectively correspond to Figure 3 the B-T, L-R, and SUM electrical signals in , that is, P2, P3, and P4. There are four measuring arms on the thrust meter, so 12 signals are output simultaneously. The signal processing scheme involved in the present invention includes a rotor part and a stator part. The rotor part uses operational amplifiers to build a conditioning circuit for the 12-channel electrical signals transmitted by the four optical measuring arms, including a voltage conversion circuit and a low-pass filter circuit that convert the voltage signal into a voltage input range suitable for the ADC chip. The ADC converts the input analog signal into a digital signal and transmits it to the lower computer SoC chip for acquisition through SPI. The lower computer inputs the collected signals into the buffer after averaging and sampling filtering a certain number of times to reduce the sampling error.

[0049] The stator part communicates with the rotor part through a 2.4G WIFI module, and all the signals of all channels after filtering in the rotor part are transmitted into the SoC chip of the stator part. The SoC of the stator part also has a zero adjustment and function self-check module, and the signals are displayed through the LCD or the data is sent to the host computer through the Ethernet, and the host computer is used to analyze and process the data.

[0050] The shaft system torque M and thrust T can be calculated from the changes in the laser spot position (Δx, Δy), and the specific formula is:

[0051]

[0052]

[0053] In the formula, E is the elastic modulus, A is the cross-sectional area of the shaft before deformation, G is the shear modulus, I p is the moment of inertia, and ΔL is the snap ring spacing, all of which are constants. Then the thrust system k T and the torque coefficient k M are constants, so they can be obtained through laboratory calibration.

Claims

1. A marine thrust and torque comprehensive monitoring device, characterized in that: It includes a power supply module, a rotor acquisition module, a snap ring, a two-dimensional optical measurement arm, a stator bracket, a power supply module beside the shaft, an acquisition instrument, and a host computer installed on a rotating shaft. The two-dimensional optical measurement arm consists of two measurement arms that can move relative to each other. One measurement arm is equipped with a laser emitter, and the other measurement arm is equipped with a quadrant detector. Both measurement arms are installed on a marine bearing through a snap ring. The light source emitted by the laser emitter directly irradiates the center position of the quadrant detector, and the optical axis direction is orthogonal to the axial direction of the bearing. By converting the out-of-plane orthogonal components into in-plane orthogonal components of the quadrant detector. When thrust and torque are generated, the light spot generates a relative displacement on the quadrant detector, and thrust and torque can be measured simultaneously.

2. The marine thrust torque comprehensive monitoring device according to claim 1, characterized in that: The quadrant detector consists of photoelectric converters symmetrically distributed in four quadrants of a rectangular coordinate system and having similar performance to form a torque-thrust optical sensor.

3. The marine thrust and torque comprehensive monitoring device according to claim 2, wherein: The photoelectric sensor chip in the torque-thrust optical sensor adopts a four-pole photodiode array, with a 7-pin connector, having a current-to-voltage amplifier. The provided sum signal is the sum of the signals of all four quadrant diodes, and the provided difference signal is the difference in the light intensity sensed by pairs of photodiode elements in the array.

4. The marine thrust and torque comprehensive monitoring device according to claim 1, characterized in that: The signal processing circuit in the marine thrust-torque integrated monitoring device includes a rotor part and a stator part. The rotor part uses operational amplifiers to build a conditioning circuit for the electrical signals of 12 channels transmitted by four optical measurement arms, including a voltage conversion circuit and a low-pass filter circuit that convert the voltage signal into a voltage input range suitable for the ADC chip. The ADC converts the input analog signal into a digital signal and transmits it to the lower computer SoC chip for acquisition through SPI. The lower computer inputs the acquired signal into a buffer after averaging and sampling filtering a certain number of times to reduce the sampling error. The stator part communicates with the rotor part through a 2.4G WIFI module and transmits all the filtered signals of all channels from the rotor part into the SoC chip of the stator part. The SoC of the stator part also has a zero adjustment and function self-check module, and transmits the signal to the host computer through LCD display or sends the data to the host computer through Ethernet for the host computer to analyze and process the data.

5. A marine thrust and torque comprehensive monitoring method, which uses a marine thrust and torque comprehensive monitoring device, is characterized in that, Specifically, it includes the following steps: Step 1: Install two snap rings on the cross-sections of the shaft section with an interval of ΔL, and evenly arrange 4 two-dimensional optical measurement arms circumferentially between the snap rings; Step 2: When there is torque and thrust in the shafting, the position of the laser spot emitted by the laser emitter on the quadrant photosensitive detector will change (Δx, Δy), and the output voltages V1, V2, V3, and V4 of the photoelectric converters in the four quadrants will also change accordingly; Step 3: The three groups of voltage signals output by the four-pole photodiode array are respectively: P2 = (V2 + V3) - (V1 + V4) P3 = (V1 + V2) - (V3 + V4) P4 = V1 + V2 + V3 + V4 Where: P2 is the electrical signal generated by the bottom quadrants D2 and D3 of the photodiode minus the voltage signal of the top quadrants D1 and D4; P3 is the voltage signal generated by the quadrants D1 and D2 of the photodiode minus the voltage signal generated by the quadrants D3 and D4; P4 is the sum of the voltage signals generated by the four quadrants D1, D2, D3, and D4 of the photodiode. Then the calculation formula for the relative displacement (Δx, Δy) of the laser spot on the four-quadrant sensor is: Δx and Δy respectively correspond to the offsets of the spot center in the x and y directions of the four-quadrant sensor. Sending the three voltage signals of P2, P3, and P4 to the signal processing unit containing the ADC enables real-time measurement of the thrust and torque in the x and y directions. Step Four: The shaft torque M and thrust T are calculated from the changes in the laser spot position (Δx, Δy), and the specific formula is: where E is the elastic modulus, A is the cross-sectional area of the shaft before deformation, G is the shear modulus, I p is the moment of inertia, and ΔL is the constant snap ring spacing, then the thrust coefficient k T and the torque coefficient k M are constants obtained through laboratory calibration.

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