Excavator pose and vibration detection system and method based on passive tag

Abstract

The invention discloses an excavator pose and vibration detection system and method based on passive tags. The excavator pose and vibration detection system comprises a passive tag array, an antenna array, a reader array and an upper computer. The passive tag array is installed on a moving part of the excavator, and after the antenna array transmits a signal to the passive tag array, the reader array can receive the signal reflected by the passive tag array; and the upper computer processes the signals received by the reader array so as to obtain the motion information of the moving part of the excavator. The moving part comprises a movable arm, a bucket rod and a bucket; the passive tag array comprises a plurality of pose tags and a plurality of vibration tags; a pose label is mounted on the movable arm; a position and posture label and a vibration label are mounted on the bucket rod; and a pose label is mounted on the twisted rope to detect the displacement of the twisted rope, and the angle of the bucket is calculated based on the displacement of the twisted rope so as to detect the pose information of the bucket. According to the invention, the space pose parameters of the moving part of the excavator can be monitored in the operation process of the excavator.

Description

Technical Field

[0001] The present invention relates to the technical field of excavator motion monitoring, and in particular to a system and method for detecting the posture and vibration of an excavator based on a passive tag. Background Art

[0002] As core equipment in the construction machinery sector, the operational safety and efficiency of electric shovel excavators are directly linked to project quality control and progress assurance. Position monitoring technology, a key enabler for ensuring safe equipment operation and improving operational precision, effectively enhances equipment operational smoothness and precision by capturing the real-time spatial position parameters of core components such as the boom, arm, and bucket. Therefore, further research into position monitoring technology has significant application value in preventing engineering accidents and optimizing construction efficiency. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an excavator posture and vibration detection system and method based on passive tags, which monitors the spatial posture parameters of the excavator's moving parts during the operation of the excavator.

[0004] Technical solution: To achieve the above-mentioned purpose, the present invention provides an excavator posture and vibration detection system based on passive tags, which includes a passive tag array, an antenna array, a reader array and a host computer; the passive tag array is installed on the moving parts of the excavator, and after the antenna array transmits a signal to the passive tag array, the reader array can receive the signal reflected by the passive tag array; the host computer processes the signal received by the reader array to obtain the posture and vibration information of the moving parts of the excavator.

[0005] Furthermore, the excavator is an electric shovel excavator, and the moving parts on the electric shovel excavator include a boom and a bucket arm; the boom is installed at the front end of the electric shovel excavator, and the middle part of the boom is rotatably connected to the bucket arm; the boom and the bucket arm can swing up and down; the passive tag array includes several posture tags; a posture tag is installed on the boom to detect the posture information of the boom; a posture tag is installed on the bucket arm to detect the posture information of the bucket arm.

[0006] Furthermore, the moving parts on the electric shovel excavator also include a bucket; the bucket is movably installed at the lower end of the bucket arm, and the bucket can swing up and down relative to the bucket arm; the electric shovel excavator is also provided with a winch, and a pulley is installed at the top of the boom, and the rope led out from the winch passes around the pulley and is connected to the bucket; a posture tag is installed on the rope to detect the displacement of the rope, and the angle of the bucket is calculated based on the displacement of the rope, so as to detect the posture information of the bucket.

[0007] Furthermore, on the electric shovel excavator, the portion of the stranded rope between the pulley and the winch is called the pull rope segment, and the portion of the stranded rope between the pulley and the bucket is called the suspension rope segment. The posture tag installed on the stranded rope is correspondingly located on the pull rope segment.

[0008] Furthermore, the passive tag array includes a plurality of vibration tags, which are mounted on the dipper arm to detect vibration shocks suffered by the electric shovel excavator.

[0009] Furthermore, a plurality of the vibration tags form a circular array on the boom.

[0010] Furthermore, a boom posture detection method for an excavator posture and vibration detection system based on passive tags includes the following steps: Step Q1: the antenna array transmits energy to the posture tags on the boom, the reader array receives and analyzes the reflected signals of the posture tags, and obtains the timestamps, RSSI values, and phase values of each posture tag on the boom; Step Q2: the RSSI value changes of adjacent timestamps are calculated, and the rotation direction of the boom is determined based on the increase and decrease trend of the RSSI values; Step Q3: the initial distance between the antenna array and each posture tag is recorded, and then the distance change between the antenna array and each posture tag is calculated, and the calculated distance change is superimposed on the initial distance to obtain the real-time distance between the antenna array and each posture tag at different times; Step Q4: based on the real-time distance between the antenna array and each posture tag, the angle θ of the boom rotation relative to the vertical direction is calculated; Step Q5: the obtained angle θ is subtracted item by item to obtain the angle of rotation of the boom at a later moment relative to the previous moment; based on the rotation direction and rotation angle of the boom, the posture information of the boom at each moment is obtained.

[0011] Furthermore, a boom posture detection method of an excavator posture and vibration detection system based on passive tags is provided, wherein at least two posture tags are installed on the boom, and the posture information of the boom is calculated based on the coordinates of the at least two posture tags; specifically comprising the following steps: Step R1: the antenna array transmits energy to the posture tag on the boom, and the reader array receives and parses the reflected signal of the posture tag to obtain the timestamp and phase value of each posture tag on the boom; Step R2: calculating the time delay difference when two antennas in the antenna array receive the reflected signal of the same posture tag; Step R3: calculating the phase difference when two readers in the reader array receive the same posture tag; Step R4: based on the calculated time delay difference and phase difference, the coordinates of the posture tag are calculated in combination with the geometric relationship; Step R5: repeating the above steps, and based on the coordinates of the posture tag, the coordinates of the boom are calculated in real time to obtain the posture information of the boom at each moment.

[0012] Furthermore, a bucket posture detection method of an excavator posture and vibration detection system based on a passive tag is provided. In the electric shovel excavator, a boom, a bucket rod, a bucket and a suspension rope segment form a closed posture judgment figure; in the posture judgment figure, after determining the angle between the boom and the bucket rod, the angle between the bucket rod and the bucket is calculated based on the length of the suspension rope segment to obtain the posture information of the bucket; specifically, the following steps are included: Step S1: The antenna array transmits energy to the posture tag on the pull rope segment, and the reader array receives and analyzes the reflected signal of the posture tag to obtain the coordinates of the posture tag on the pull rope segment; Step S2: Obtain the coordinates of the boom and the bucket rod. and determine the angle between the boom and the arm according to the posture information of the boom and the arm; step S3: combining the coordinates of the posture label on the rope segment and the posture information of the boom, obtain the length of the rope segment, and then obtain the length of the suspension rope segment; step S4: in the posture judgment graph, since the lengths of the boom, the arm, the bucket and the suspension rope segment are known, and the angle between the boom and the arm is also known, the angle between the bucket and the arm can be calculated according to the geometric relationship; step S5: repeat the above steps, and determine the angle between the bucket and the arm in real time through the coordinate changes of the posture label, so as to obtain the posture information of the bucket at each moment.

[0013] Furthermore, a vibration detection method for an excavator posture and vibration detection system based on passive tags includes the following steps: Step T1: the antenna array transmits energy to each vibration tag, and the reader receives and analyzes the reflected signal of the vibration tag to obtain the timestamp and phase value of each vibration tag; Step T2: unwrapping the phase sequence of the received signal to establish a continuous phase change curve; Step T3: performing fast Fourier transform on the corrected phase sequence, and extracting the resonance peak through local maximum detection and parabolic interpolation; Step T4: when a sharp resonance peak is detected, it is determined to be a mechanical impact event.

[0014] Beneficial effects: The excavator posture and vibration detection system and method based on passive tags of the present invention have the following beneficial effects:

[0015] 1) The motion information of the electric shovel is detected through a passive tag array. Passive tags are small in size and low in power consumption. They can be distributed on the key moving parts of the electric shovel and have little impact on the performance of the power plant excavator, significantly reducing system complexity and subsequent maintenance costs.

[0016] 2) When detecting the bucket's posture, the posture label is not directly affixed to the bucket. Instead, it is affixed to the rope. By detecting the displacement of the rope to infer the bucket's posture information, the problem of the posture label being easily damaged when affixed to the bucket can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attachment Figure 1This is a structural diagram of an electric shovel excavator;

[0018] Attachment Figure 2 Schematic diagram of the circular deployment of vibration tags on the cross section of the boom;

[0019] Attachment Figure 3 This is a schematic diagram of a method for detecting the posture of an electric shovel excavator boom;

[0020] Attachment Figure 4 This is a schematic diagram of a method for detecting the posture of an electric shovel excavator arm;

[0021] Attachment Figure 5 Schematic diagram of the posture detection method for the bucket of an electric shovel excavator. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] As attached Figures 1 to 5 The passive tag-based excavator posture and vibration detection system comprises a passive tag array, an antenna array 2, a reader array 1, and a host computer 3. The passive tag array is mounted on the moving parts of the excavator. After the antenna array 2 transmits a signal to the passive tag array, the reader array 1 can receive the signal reflected by the passive tag array. The host computer 3 processes the signal received by the reader array 1 to obtain vibration and posture information of the moving parts of the excavator.

[0024] Since the passive tag array is a passive non-contact sensor, and the passive tags are small in size and low in power consumption, they can be distributed at the key nodes of the excavator equipment, with little impact on the performance of the excavator equipment, greatly reducing the system complexity and subsequent maintenance costs, and providing an innovative technical path for building an excavator motion monitoring system.

[0025] Specifically, refer to the attached Figure 1 As shown in the figure, the excavator is an electric shovel excavator, and the moving parts on the electric shovel excavator include a boom 7, a bucket arm 9 and a bucket 8; the boom 7 is installed at the front end of the electric shovel excavator, the middle part of the boom 7 is rotatably connected to the bucket arm 9, and the lower end of the bucket arm 9 is movably installed with the bucket 8, and the boom 7, the bucket arm 9 and the bucket 8 can swing up and down; the electric shovel excavator is also provided with a winch 12, and a pulley 15 is installed at the top of the boom 7. The rope 6 led out from the winch 12 passes around the pulley 15 and is connected to the bucket 8.

[0026] The tags in the passive tag array are anti-metal RFID tags. The tag base is made of flexible material and is arranged in an adhesive manner. In order to further prevent the passive tags from falling off during device operation, a layer of transparent tape can be pasted on their surface or a rope can be wrapped around the device surface.

[0027] The host computer 3 is arranged in the operating room 4 of the electric shovel excavator, and is used to start the reader, transmit signals and process backscattered information, and then calculate the position and vibration information of the electric shovel excavator based on the RSSI value, phase value and timestamp of the tag array.

[0028] The antenna array 2 includes multiple UHF antennas, which are arranged vertically on a platform next to the operator's cab 4 via brackets. These brackets are used for signal communication with the passive tag array. The brackets are made of lightweight aluminum alloy and can be bolted to the platform of the electric shovel to ensure they are not affected by the environment or equipment operation. Preferably, four UHF antennas are arranged vertically on the electric shovel, with two antenna arrays 2 forming a group, two below and two above. The two antennas in a group of antenna arrays 2 are spaced a certain distance apart, and the distance between the two groups of antenna arrays 2 is slightly greater than the distance between the two antennas in a group of antenna arrays 2.

[0029] The reader is connected to the UHF antenna and the host computer 3 to control the UHF antenna to send signals to the passive tag array. Preferably, the host computer 3 is a high-performance computer connected to the reader via a serial data port, and the reader is connected to the UHF antenna via a feeder.

[0030] The passive tag array includes several posture tags 5, which are used to detect the posture information of the core moving components of the electric shovel excavator. Specifically, a posture tag 5 is installed on the boom 7 to detect the posture information of the boom 7. A posture tag 5 is installed on the dipper arm 9 to detect the posture information of the dipper arm 9.

[0031] When using passive tags to detect the position and posture information of the bucket arm 9 and boom 7, the tags are directly attached to the bucket arm 9 and boom 7. However, when an electric shovel is operating, the bucket 8 will rub and squeeze against the material. If the passive tags are directly attached to the bucket 8, the friction and squeezing of the material will easily damage them. Therefore, when using passive tags to detect the position and posture information of the bucket 8, directly attaching the tags to the bucket 8 is not appropriate.

[0032] Therefore, in the present invention, the posture tag 5 is attached to the rope 6 to detect the displacement of the rope 6. Based on the displacement of the rope 6, the angle of the bucket 8 is calculated to detect the posture information of the bucket 8. This solves the problem that passive tags directly attached to the bucket 8 are easily damaged by wear and tear.

[0033] As attached Figure 1As shown in , on the electric shovel excavator, the portion of the stranded rope 6 between the pulley 15 and the winch 12 is called the pull rope segment 13, and the portion of the stranded rope 6 between the pulley 15 and the bucket 8 is called the suspension rope segment 14. The posture tag 5 installed on the stranded rope 6 is correspondingly located on the pull rope segment 13. If the posture tag 5 is installed on the pull rope segment 13, then when the stranded rope 6 pulls the bucket 8 to rise, the posture tag 5 on the pull rope segment 13 may slip to the pulley 15, causing damage to the posture tag 5. Therefore, the posture tag 5 is installed on the pull rope segment 13, and it is necessary to ensure that when the bucket 8 drops to the lowest point, the posture tag 5 can still be located on the pull rope segment 13.

[0034] As attached Figure 1 As shown in , a spatial rectangular coordinate system is established with the vertically arranged UHF antenna as the z-axis and the plane where the UHF antenna and the posture tag 5 on the stick 9 are located as the xoz plane, so as to calculate the coordinates of each component on the electric shovel excavator.

[0035] A boom posture detection method of an excavator posture and vibration detection system based on a passive tag, wherein the posture monitoring of the boom 7 includes the following steps:

[0036] Step Q1: Multiple UHF antennas in the antenna array 2 simultaneously transmit energy to the posture tag 5 on the boom 7 of the electric shovel excavator. After receiving the signal, the tag reflects the signal to the UHF antenna and transmits it to the reader array 1. The reader array 1 receives and analyzes the signal to obtain the timestamp, RSSI value and phase value of each posture tag 5;

[0037] Step Q2: Calculate the change in RSSI values between adjacent timestamps: If the RSSI value of the latter timestamp is smaller than that of the previous timestamp, it indicates that the boom 7 is rotating around the rotation center in a direction away from the operating room 4; conversely, if the RSSI value increases, the boom 7 is rotating around the rotation center in a direction closer to the operating room 4. By calculating the RSSI difference between adjacent timestamps one by one, the rotation direction of the boom 7 during movement can be determined in real time;

[0038] Step Q3: Record the initial distance between the antenna and each posture tag 5, then calculate the distance change between the antenna and each posture tag 5, and superimpose the calculated distance change on the initial distance to obtain the real-time distance between the antenna and each posture tag 5 at different times;

[0039] Specifically, refer to the attached Figure 3 As shown in , in the initial state, first record the initial distance between the multi-antenna and each posture tag 5 and the distance between the center of the posture tag 5 on the boom 7 and the center of the antenna in the y-axis direction. When the electric shovel excavator starts running, calculate the phase change value of the adjacent timestamps according to the formula:

[0040]

[0041] Solve the distance change from multiple antennas to each tag, and superimpose the calculated distance change on the initial distance to obtain the real-time distance between the antenna and the tag at different times during the movement of the electric shovel. Then, the projection distance of this distance on the xoz plane can be obtained. In the formula, φ t-1 is the phase value of the previous timestamp, φ t is the phase value of the next timestamp;

[0042] Step Q4: Based on the real-time distance between the antenna and each posture tag 5, the angle θ of the arm 7 relative to the vertical direction is calculated; Figure 3 As shown in , A0 is the actual position of the antenna, A1 is the projection of the antenna on the xoz plane where the center of the pose tag 5 array on the boom 7 is located, O is the boom rotation center 11, B and C are the pose tag 5 arrays, α is the angle between the line connecting the UHF antenna and the boom rotation center 11 and the vertical line from the antenna to the boom rotation center 11, β is the angle between the line connecting the UHF antenna and the boom rotation center 11 and the boom 7, and θ is the angle of rotation of the boom 7 relative to the vertical direction. It can be seen from the angular relationship that:

[0043]

[0044] Combined with the law of cosines:

[0045] |A1B| 2 =|A1O| 2 +|BO| 2 -2|A1O||BO|cosβ,

[0046] |A1C| 2 =|A1O| 2 +|CO| 2 -2|A1O||CO|cosβ,

[0047] Obtain the rotation angles of the boom 7 measured by multiple antennas, and average the multiple measured angle values to obtain the angle θ of the boom 7 rotation; where α is the angle between the line connecting the UHF antenna and the boom rotation center 11 and the perpendicular line from the antenna to the boom rotation center 11 in the vertical direction, β is the angle between the line connecting the UHF antenna and the boom rotation center 11 and the boom 7, and θ is the angle of rotation of the boom 7 relative to the vertical direction;

[0048] Step Q5: Calculate the difference of the obtained angle θ item by item to obtain the angle Δθ=θ of the boom 7 rotation at the next moment relative to the previous moment t -θ t-1 Repeat the above steps to calculate the rotation direction and rotation angle of the boom 7 in real time, and obtain the motion state of the boom 7 at each moment of the electric shovel excavator; where, θt-1 is the angle value calculated at the previous moment, θ t The angle value calculated at the next moment.

[0049] The passive tag collects data randomly, and the data includes the collected timestamp, RSSI value, and phase value. Considering that the movement mode of the boom 7 is fixed-axis rotation, the posture state of the boom 7 can be represented by the rotation angle. The antennas are arranged in a vertical array, and the distance between each antenna and the boom's rotation center 11 remains fixed. The distance between the posture tag 5 and the antenna changes in real time. The relationship between the RSSI value and the distance is inversely proportional to the distance, which is used to determine the coarse-grained rotation direction. The phase change value of the previous and next timestamps can be used to calculate the distance change between the posture tag 5 and the antenna, thereby obtaining the distance between the posture tag 5 and the antenna at each moment. This is then mapped to the xoz plane. In the xoz plane, the rotation angle of the boom 7 is solved by combining the antenna projection and the geometric configuration of the posture tag 5 with the angle relationship, and the posture state of the boom 7 is determined. Through the complementarity of RSSI and phase data, high-precision real-time measurement of the rotation direction and angle of the boom 7 is achieved. The use of multi-antenna collaborative measurement effectively suppresses errors caused by single-antenna signal shielding or environmental noise, improving the robustness of the system.

[0050] A method for detecting the arm posture of an excavator posture and vibration detection system based on passive tags, wherein at least two posture tags 5 are installed on the arm 9, and the posture information of the arm 9 is calculated based on the coordinates of the at least two posture tags 5; monitoring the posture of the arm 9 includes the following steps:

[0051] Step R1: Multiple UHF antennas simultaneously transmit energy to the posture tag 5 on the dipper arm 9 of the electric shovel excavator. The tag reflects the signal to the UHF antenna and transmits it to the reader to obtain the timestamp and phase value of each posture tag 5;

[0052] Step R2: Calculate the time delay difference Δt=t between the two antennas in the antenna array 2 receiving the same pose tag 5 i+1 -t i , where t i , t i+1 are the time when two antennas receive the reflected signal of tag 5 with the same posture;

[0053] Then by the formula The phase difference between two adjacent readers receiving the same pose tag 5 is calculated as follows: where f is the frequency transmitted by the UHF antenna, which is generally 915 MHz.

[0054] Step R3: Refer to the attached Figure 4 As shown in , using the angle of arrival formula:

[0055]

[0056] Calculate the angles δ1 and δ2 between the pose tag 5 and the center of the antenna array 2; where Δx is the spacing between two antennas in a set of antenna array 2, λ is the wavelength, which can be calculated using the formula λ = c / f, and c is the speed of light;

[0057] Taking the bottom antenna in antenna array 2 as the coordinate origin (0, 0), combined with the geometric relationship:

[0058]

[0059] Calculate the coordinates of the pose label 5 in the two-dimensional plane, where (a i , b i ) is the coordinate of pose label 5, (x i , z i ) are the coordinates of the antenna;

[0060] Step R4: Repeat the above steps to calculate the coordinates of the boom 9 in real time to obtain the posture information of the boom 9 at each moment.

[0061] As attached Figure 4 As shown in , A is the posture tag 5, B1-B4 are two groups of antenna arrays 2, and δ1 and δ2 are the arrival angles from the posture tag 5 to the two groups of antenna arrays 2. In actual application, two posture tags 5 are attached to the arm 9 and the boom 7 respectively.

[0062] Considering that the boom 9 always moves in the xoz plane, the posture state of the boom 9 can be calculated using the coordinate information of the two posture tags 5. The UHF antenna is arranged in a vertical array, and the center of the UHF antenna and the center of the posture tag 5 on the boom 9 are located in the same plane. The two antennas form a group of antenna arrays 2. Due to the different distances between the antenna arrays 2 and the posture tags 5, there is a time delay difference when different antennas receive the signals transmitted by the same posture tag 5. Therefore, the phase difference between the antennas can be calculated, and then the arrival angle of the different posture tags 5 relative to the two groups of antenna arrays 2 can be calculated. The coordinates of the posture tag 5 on the boom 9 can be calculated from the arrival angle and the coordinates of the antenna arrays 2, and the posture state of the boom 9 can be determined. By arranging the posture tag 5 and the antenna in the same plane, the coordinate positioning of the posture tag 5 in the two-dimensional plane is achieved. Using geometric modeling and phase solution, the spatial posture parameters of the boom 9 are obtained in real time, providing dynamic data support for the motion control, posture adjustment, and automated operation of the electric shovel excavator.

[0063] A method for detecting the bucket posture of an excavator posture and vibration detection system based on a passive tag, wherein in the electric shovel excavator, a boom 7, a bucket arm 9, a bucket 8, and a suspension rope segment 14 form a closed posture judgment figure 16; in the posture judgment figure 16, after determining the angle between the boom 7 and the bucket arm 9, the angle between the bucket arm 9 and the bucket 8 is calculated based on the length of the suspension rope segment 14 to obtain the posture information of the bucket 8; the method specifically comprises the following steps:

[0064] Step S1: The antenna array 2 transmits energy to the posture tag 5 on the rope segment 13, and the reader array 1 receives and analyzes the reflected signal of the posture tag 5 to obtain the coordinates of the posture tag 5 on the rope segment 13;

[0065] Step S2: obtaining the posture information of the boom 7 and the arm 9, and determining the angle between the boom 7 and the arm 9 according to the posture information of the boom 7 and the arm 9;

[0066] Step S3: combining the coordinates of the posture tag 5 on the pull rope segment 13 and the posture information of the boom 7 to obtain the length of the pull rope segment 13 and then the length of the suspension rope segment 14;

[0067] Step S4: In the posture judgment graph 16, since the lengths of the boom 7, arm 9, bucket 8, and rope segment 14 are known, and the angle between the boom 7 and arm 9 is also known, the angle between the bucket 8 and arm 9 can be calculated based on the geometric relationship;

[0068] Step S5: Repeat the above steps to determine the angle between the bucket 8 and the dipper arm 9 in real time through the coordinate changes of the posture label 5, thereby obtaining the posture information of the bucket 8 at each moment.

[0069] Specifically, in conjunction with Figure 5 An example is given to illustrate how to calculate the angle of bucket 8 based on the coordinate changes of posture label 5 in step S4. The posture label 5 on the strand 6 is point P, the pulley 15 is approximately regarded as point Q, the connection point between strand 6 and bucket 8 is point R, the connection point between arm 9 and bucket 8 is point S, and the connection point between arm 9 and boom 7 is point T. The lengths of QT, TS, and RS are all known quantities. Then, the following steps are performed:

[0070] Step S4.1: Based on the attachment position of the posture label 5 on the rope 6, the length of the rope 6 between the posture label 5 and the bucket 8 is obtained, that is, the sum of the lengths PQ and QR;

[0071] Step S4.2: Measure the coordinates of the pose tag 5, i.e., the coordinates of point P. The same measurement method can be used to measure the coordinates of the pose tags 5 on the boom 9 and the rope 6. Then, based on the length and rotation angle of the boom 7, the coordinates of the pulley 15, i.e., the coordinates of point Q, are obtained.

[0072] Step S4.3: Combine the coordinates of points P and Q to obtain the length of PQ. Since the sum of the lengths of PQ and QR is known, the length of QR can also be obtained.

[0073] Step S4.4: Combining the posture information of the arm 9 and the boom 7, the angle between the arm 9 and the boom 7, i.e., the angle ∠QTS, is obtained;

[0074] Step S4.5: In △QTS, since the lengths of QT and TS are known, and the angle ∠QTS is known, the length of QS can be calculated using the law of cosines.

[0075] Step S4.6: In △QRS, since the lengths of QR, RS and QS are known, the angle of ∠QSR can be calculated according to the law of cosines; correspondingly, in △QTS, since the lengths of QT, TS and QS are known, the angle of ∠QST can also be calculated according to the law of cosines; add the angles of ∠QSR and ∠QST to obtain the angle of ∠RST, which is the angle between the bucket 8 and the boom 9. From this, the angle of the bucket 8 can be determined and the posture information of the bucket 8 can be obtained.

[0076] Because pulley 15 is actually circular, the position information of bucket 8 calculated using the method described in the above embodiment will have some error. However, since the diameter of pulley 15 can also be determined based on the parameters of the electric shovel excavator, the shape of position determination graph 16 is fixed if the lengths of boom 7, arm 9, bucket 8, and rope segment 14 are known, as well as the angle between boom 7 and arm 9. Therefore, the exact value of the angle between bucket 8 and arm 9 can be calculated using geometric relationships, thereby more accurately detecting the position of bucket 8.

[0077] The passive tag array also includes several vibration tags 10, which are mounted on the dipper arm 9 to detect vibration impacts on the electric shovel. Preferably, the vibration tags 10 and the posture tags 5 are placed at different locations on the same part of the electric shovel, and the distance between the two tags is much greater than the distance between the tags in the multi-tag array to reduce signal interference between different types of tags.

[0078] The vibration tags 10 form a circular array on the boom 9. Specifically, the vibration tags 10 are arranged in a circular manner on the four sides of the boom 9 to detect vibration conditions in all directions of the electric shovel excavator.

[0079] The present invention also provides a vibration detection method for an excavator posture and vibration detection system based on a passive tag, wherein the vibration monitoring of an electric shovel excavator comprises the following steps:

[0080] Step T1: The antenna array 2 transmits energy to the vibration tags 10 on the dipper arm 9 of the electric shovel. After receiving the energy, the tags reflect the signal to the antenna array 2 and transmit it to the reader array 1. The reader array 1 receives and analyzes the signal to obtain the timestamp and phase value of each vibration tag 10.

[0081] Step T2: Unwrapping the phase sequence of the received signal: Using an adaptive unwrapping algorithm based on a sliding window, the window length is dynamically adjusted according to the sampling rate. The phase difference between adjacent points is detected frame by frame. When the jump value exceeds the π / 2 threshold, ±π compensation is used to eliminate cross-cycle ambiguity. Recursive compensation is used to correct continuous jump points. Kalman filtering is combined to smooth residual noise. After unwrapping, the continuity of the second-order derivative of the phase curve is verified. Abnormal jump points trigger resampling or are marked as invalid data, ultimately generating a continuous phase change curve.

[0082] Step T3: Perform a fast Fourier transform (FFT) on the corrected phase sequence, using a Hanning window weighting to improve frequency domain resolution. Record the spectrum energy baseline under shock-free conditions, and extract the resonance peak through local maximum detection and parabolic interpolation. The peak amplitude exceeding the baseline by 3dB, the half-width less than 5Hz, and the energy accumulation at the same frequency point within three consecutive vibration cycles are set as valid criteria to effectively distinguish between broadband noise and transient mechanical shock.

[0083] Step T4: When a sharp resonance peak is detected, it is determined to be a mechanical shock event; Figure 2 As shown in the figure, the vibration tags on the boom 9 are numbered 101, 102, 103 and 104 according to their positions, among which the vibration tags 101 and 103 are installed symmetrically along the j axis of the cross section of the boom 9 and are sensitive to vibration in the i direction; the vibration tags 102 and 104 are installed symmetrically along the i axis of the cross section of the boom 9 and mainly measure impact vibration in the j direction. If the frequency spectrum of the vibration tags 101 and 103 detects an impact resonance peak, it means that the bucket 8 has been subjected to a vibration impact in the j direction. If the frequency spectrum of the vibration tags 102 and 104 detects an impact resonance peak, it means that the bucket 8 has been subjected to a vibration impact in the i direction. If all four tags detect an ultra-threshold peak, it means that the bucket 8 has been subjected to a combined impact from the i and j directions.

[0084] Taking into account the situation that during the vibration of the tag, the distance between the vibration tag 10 and the antenna array 2 may exceed the wavelength of the antenna array 2, resulting in a phase jump between 0 and 2π. By setting the threshold of the phase jump, the adjacent sampling points are detected frame by frame for phase compensation to balance the periodic phase changes caused by the phase jump. The vibration of the electric shovel excavator mainly comes from the vibration impact on the bucket 8, and the impact vibration will be transmitted to the bucket arm 9 through the end of the bucket 8. The impact direction is mainly in the plane where the cross section of the bucket arm 9 is located. The vibration tags 10 are arranged in a ring around the bucket arm 9. The vibration direction and vibration frequency of the electric shovel excavator after the impact can be determined by detecting the impact resonance peak on the spectrum.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A passive tag-based excavator posture and vibration detection system, characterized by: The invention comprises a passive tag array, an antenna array (2), a reader array (1) and a host computer (3); the passive tag array is installed on the moving parts of the excavator, and after the antenna array (2) transmits a signal to the passive tag array, the reader array (1) can receive the signal reflected by the passive tag array; the host computer (3) processes the signal received by the reader array (1) to obtain the position and vibration information of the moving parts of the excavator.

2. The excavator posture and vibration detection system based on passive tags according to claim 1 is characterized in that: The excavator is an electric shovel excavator, and the moving parts of the electric shovel excavator include a movable arm (7) and a bucket rod (9); the movable arm (7) is installed at the front end of the electric shovel excavator, and the middle part of the movable arm (7) is rotatably connected to the bucket rod (9); the movable arm (7) and the bucket rod (9) can swing up and down; The passive tag array includes a plurality of posture tags (5); a posture tag (5) is installed on the boom (7) to detect the posture information of the boom (7); and a posture tag (5) is installed on the boom (9) to detect the posture information of the boom (9).

3. The excavator posture and vibration detection system based on passive tags according to claim 2 is characterized in that: The moving parts on the electric shovel excavator also include a bucket (8); the bucket (8) is movably installed at the lower end of the bucket arm (9), and the bucket (8) can swing up and down relative to the bucket arm (9); the electric shovel excavator is also provided with a winch (12), and a pulley (15) is installed at the top of the boom (7); the rope (6) drawn from the winch (12) passes around the pulley (15) and is connected to the bucket (8); a posture tag (5) is installed on the rope (6) to detect the displacement of the rope (6), and the angle of the bucket (8) is calculated based on the displacement of the rope (6), so as to detect the posture information of the bucket (8).

4. The excavator posture and vibration detection system based on passive tags according to claim 3 is characterized in that: On the electric shovel excavator, the portion of the stranded rope (6) between the pulley (15) and the winch (12) is called the pull rope segment (13), and the portion of the stranded rope (6) between the pulley (15) and the bucket (8) is called the suspension rope segment (14). The posture tag (5) installed on the stranded rope (6) is correspondingly located on the pull rope segment (13).

5. The passive tag-based excavator posture and vibration detection system according to claim 2, characterized in that: The passive tag array comprises a plurality of vibration tags (10), which are mounted on a dipper arm (9) to detect vibration shocks suffered by an electric shovel excavator.

6. The passive tag-based excavator posture and vibration detection system according to claim 5, characterized in that: A plurality of vibration tags (10) form a circular array on the boom (9).

7. The boom posture detection method of the excavator posture and vibration detection system based on passive tags according to claim 2 is characterized in that: The following steps are involved: Step Q1: The antenna array (2) transmits energy to the posture tags (5) on the movable arm (7), and the reader array (1) receives and analyzes the reflected signals of the posture tags (5), and obtains the timestamp, RSSI value and phase value of each posture tag (5) on the movable arm (7); Step Q2: Calculate the change of RSSI values of adjacent time stamps, and determine the rotation direction of the boom (7) based on the increase and decrease trend of the RSSI values; Step Q3: Record the initial distance between the antenna array (2) and each posture tag (5), then calculate the distance change between the antenna array (2) and each posture tag (5), and superimpose the calculated distance change on the initial distance to obtain the real-time distance between the antenna array (2) and each posture tag (5) at different times; Step Q4: Based on the real-time distance between the antenna array (2) and each pose tag (5), the angle θ of the boom (7) relative to the vertical direction is calculated; Step Q5: performing difference calculation on the obtained angle θ item by item to obtain the rotation angle of the boom (7) at the next moment relative to the previous moment; based on the rotation direction and rotation angle of the boom (7), obtaining the posture information of the boom (7) at each moment.

8. The method for detecting arm posture of an excavator posture and vibration detection system based on a passive tag according to claim 2, characterized in that: At least two posture tags (5) are installed on the boom (9), and the posture information of the boom (9) is calculated based on the coordinates of the at least two posture tags (5); The specific steps include: Step R1: The antenna array (2) transmits energy to the posture tags (5) on the boom (9), and the reader array (1) receives and analyzes the reflected signals of the posture tags (5), and obtains the timestamp and phase value of each posture tag (5) on the boom (9); Step R2: Calculate the time delay difference between the two antennas in the antenna array (2) receiving the reflected signal of the tag (5) with the same posture; Step R3: Calculate the phase difference between two readers in the reader array (1) receiving the same pose tag (5); Step R4: Based on the calculated delay difference and phase difference, the coordinates of the pose tag (5) are calculated in combination with the geometric relationship; Step R5: Repeat the above steps, calculate the coordinates of the boom (9) in real time based on the coordinates of the posture label (5), and obtain the posture information of the boom (9) at each moment.

9. The bucket posture detection method of the excavator posture and vibration detection system based on passive tags according to claim 4, characterized in that: In the electric shovel excavator, a boom (7), a bucket (9), a bucket (8) and a suspension rope section (14) form a closed posture judgment figure (16); in the posture judgment figure (16), after determining the angle between the boom (7) and the boom (9), the angle between the boom (9) and the bucket (8) is calculated based on the length of the suspension rope section (14) to obtain the posture information of the bucket (8); specifically, the following steps are included: Step S1: The antenna array (2) transmits energy to the posture tag (5) on the pull rope segment (13), and the reader array (1) receives and analyzes the reflected signal of the posture tag (5) to obtain the coordinates of the posture tag (5) on the pull rope segment (13); Step S2: obtaining the position information of the boom (7) and the bucket arm (9), and determining the angle between the boom (7) and the bucket arm (9) according to the position information of the boom (7) and the bucket arm (9); Step S3: combining the coordinates of the posture label (5) on the pull rope segment (13) and the posture information of the boom (7), obtaining the length of the pull rope segment (13), and then obtaining the length of the suspension rope segment (14); Step S4: In the posture judgment graph (16), since the lengths of the boom (7), the arm (9), the bucket (8) and the suspension rope section (14) are known, and the angle between the boom (7) and the arm (9) is also known, the angle between the bucket (8) and the arm (9) can be calculated based on the geometric relationship; Step S5: Repeat the above steps to determine the angle between the bucket (8) and the dipper arm (9) in real time through the coordinate changes of the posture label (5), thereby obtaining the posture information of the bucket (8) at each moment.

10. The vibration detection method of the excavator posture and vibration detection system based on passive tags according to claim 6, characterized in that: The following steps are involved: Step T1: The antenna array (2) transmits energy to each vibration tag (10), and the reader receives and analyzes the reflected signal of the vibration tag (10), and obtains the time stamp and phase value of each vibration tag (10); Step T2: Unwrap the phase sequence of the received signal to establish a continuous phase change curve; Step T3: Perform fast Fourier transform on the corrected phase sequence and extract the resonance peak through local maximum detection and parabolic interpolation; Step T4: When a sharp resonance peak is detected, it is determined to be a mechanical shock event.

Images