Wire attitude prediction method based on inertial measurement technology

Abstract

The present invention provides a method for predicting the posture of a conductor based on inertial measurement technology, which relates to the technical field of conductor dancing prediction, including obtaining the function a(t) of the acceleration and time of the conductor in the vertical direction at the middle position, and obtaining the frequency f of the function a(t) by Fourier transform method; predicting the conductor sweep length l; predicting the diameter d of the conductor sweep range; and establishing a human-computer interactive conductor posture prediction model image, wherein the conductor posture prediction model image is shuttle-shaped as a whole. The present invention predicts the frequency of the overhead conductor displacement by calculating the frequency of the acceleration and time function obtained by the inertial sensor, and predicts the sweep length of the overhead conductor based on the difference between the maximum and minimum values ​​of the acceleration and time function and the predicted frequency of the overhead conductor displacement, so that the establishment of the model does not rely on visual image acquisition, does not require synchronization time, and can be established solely by relying on inertial measurement technology.

Description

Technical Field

[0001] The present invention relates to the technical field of wire dancing prediction, and in particular to a wire posture prediction method based on inertial measurement technology. Background Art

[0002] During high-voltage power transmission, when the overhead wires are affected by weather conditions, uneven ice coverage occurs on the wire body. At the same time, a low-frequency, large-amplitude self-excited vibration is formed under the continuous influence of lateral wind force and the line's own parameters. This phenomenon is called wire galloping.

[0003] There are currently three main explanations for the formation mechanism of conductor dancing, namely: Den Hartog's vertical dancing theory, O. Nigol's torsional dancing theory and P. Yu's eccentric inertial coupling mechanism. They all explain that the self-excitation process of the dancing of transmission lines is not completed instantly, but the conductor first experiences high-frequency, small-amplitude breeze vibration under the action of external force, and then develops into conductor dancing. Therefore, online monitoring technology can be used to detect the development trend of conductor dancing in advance, and emergency measures can be taken to avoid accidents as much as possible.

[0004] At present, the prediction of the wire posture is based on the wire state captured by image, and is predicted in conjunction with inertial measurement technology (inertial measurement is used as an auxiliary). Since the accuracy of image acquisition is difficult to ensure, the time synchronization of inertial measurement parameters and image acquisition is difficult to ensure, and the coordinate system conversion error is large, the technology has been slowly advanced. Therefore, the present invention provides a wire posture prediction method that relies solely on inertial measurement technology. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a wire attitude prediction method based on inertial measurement technology, which solves the problem that the wire attitude prediction currently used with inertial measurement as an aid is difficult to implement.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The method for predicting the attitude of a wire based on inertial measurement technology is characterized by comprising the following steps:

[0008] S1. Obtain the function a(t) of the acceleration of the conductor in the vertical direction at the middle position and time, and calculate the frequency f of the function a(t) by Fourier transform method;

[0009] S2, predict the conductor wave length l according to formula ① and ②;

[0010] F(t)max-F(t)min=k(Ll)lM f(Ll)l-gl ①;

[0011] F(t)=a(t)*gl②;

[0012] In formulas ① and ②, L represents the length of the conductor between adjacent towers, g represents the deadweight of the conductor per unit length, k is a short-time constant, f is the frequency of function a(t), and M represents the unit mass, M=1kg;

[0013] S3, according to formula ③ predict the diameter d of the wire range;

[0014] ③;

[0015] In formula ③, t1 represents the moment when a(t)=0, and t2 represents the next moment when a(t)=0 after t1;

[0016] S4. Establish a human-computer interactive wire posture prediction model image, the wire posture prediction model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d.

[0017] Preferably, it also includes:

[0018] Obtaining a function a0(t) of the acceleration of the conductor in the vertical direction at a measurement position other than the middle position and time;

[0019] According to formula ④, the diameter d0 of the wave range of the wire at the measurement position is predicted;

[0020] ④;

[0021] In formula ④, t5 represents the moment when a0(t)=0, and t6 represents the next moment when a0(t)=0 after t5;

[0022] The wire posture prediction model image of human-computer interaction is corrected according to the predicted diameter d0 of the sweep range of the wire at the measurement position; specifically:

[0023] Taking the distance l0 between the acceleration sensor measuring the acceleration and time function a0(t) and the middle position of the wire as a reference, the diameter of the cross-sectional circle at the distance l0 from the middle position of the shuttle in the wire posture prediction model image is adjusted to d0.

[0024] Preferably, the method further comprises: symmetrically installing two sets of weight-reducing anti-dance devices on the conductor at a position L1 away from the middle position of the conductor;

[0025] When the predicted wire sweep length l is greater than the distance L1 between the weight anti-dance device and the middle position of the wire, the L1 distance is used as the overall length of the shuttle of the wire posture prediction model image; and the value of k(Ll)l is calculated. When k(Ll)l is greater than the preset threshold F 升 When the load is too high, the wire is predicted to gallop severely.

[0026] Preferably, the specific method of obtaining the function a(t) of the acceleration of the wire in the vertical direction at the middle position and time in S1 is:

[0027] An inertial acceleration sensor is fixedly installed at the middle position of the wire;

[0028] A wireless gateway is installed on the power tower; the inertial acceleration sensor is connected to the wireless gateway on the power tower based on wireless ad hoc network technology, and the wireless gateway on the power tower collaboratively controls the inertial sensor through the ad hoc network to complete data collection and communication functions.

[0029] Preferably, the specific method of predicting the conductor wave length l according to equations ① and ② in S2 is:

[0030] Obtain at least two segments of function a(t) within a preset time T, substitute function a(t) into equations ① and ② respectively, solve the roots of the equations, and obtain the predicted conductor sweep length l and short-time constant k;

[0031] k is a constant value within a time period less than the preset time T.

[0032] Preferably, the acceleration sequence acquired by the acceleration sensor is: (a n (n=1,2,3,...,N),t n ), and the objective function a(t) is obtained by fitting the trigonometric least squares method.

[0033] Preferably, the method further comprises: obtaining a function a2(t) of the acceleration of the conductor in a non-vertical direction at the middle position and time,

[0034] According to formula ⑤, the diameter d2 of the wire coverage is predicted;

[0035] ⑤;

[0036] In formula ⑤, t3 represents the moment when a2(t)=0, and t4 represents the next moment when a2(t)=0 after t3;

[0037] Establishing a human-computer interactive wire posture prediction auxiliary model image, the wire posture prediction auxiliary model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d2;

[0038] The wire posture prediction model image and the wire posture prediction auxiliary model image are subjected to Boolean union operation to obtain the final wire posture model.

[0039] Preferably, the predicted wire is located at an outer contour position of the final wire posture model.

[0040] The present invention provides a method for predicting the attitude of a wire based on inertial measurement technology, which has the following beneficial effects:

[0041] 1. The present invention calculates the frequency of the acceleration and time function obtained by the inertial sensor to predict the frequency of the overhead wire displacement, and predicts the sweep length of the overhead wire according to the difference between the maximum and minimum values ​​of the acceleration and time function and the predicted frequency of the overhead wire displacement, and integrates the acceleration and time function to obtain the displacement of the middle position of the wire, thereby establishing a human-computer interactive wire posture prediction model image, the wire posture prediction model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length, the diameter of the shuttle middle position is the predicted diameter of the wire sweep range, the establishment of the model does not rely on visual image acquisition, does not require synchronization time, and can be established solely by relying on inertial measurement technology, relying on the model to predict whether the wire posture is dancing in a safe area (whether the wire posture prediction model image exceeds the safe area), and when the wire dancing develops in an uncontrollable direction, the staff is guided to take emergency measures to avoid accidents as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the principle of the wire attitude prediction method based on inertial measurement technology proposed in the present invention;

[0043] Figure 2 A graph of the a(t) function obtained for an inertial sensor. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Embodiment 1:

[0046] Overhead wires dance under the action of ice and wind. This dance is limited by the weight and flexible deformation of the wires themselves, so the dance moves within the range of an ellipse (which is simplified to a circle in this model).

[0047] Among the entire overhead wire, the wire in the middle position is most likely to produce flexible deformation. The dancing of the wire always extends from the middle position of the overhead wire to both sides. In the early stage of the wire dancing, the wire in the middle position may produce high-frequency vibration, which in turn causes the two ends of the overhead wire generating the high-frequency vibration section to extend outward, and finally causes the entire overhead wire (referring to the entire overhead wire between the two towers) to produce destructive dancing, causing serious accidents.

[0048] like Figure 1-Figure 2 As shown, an embodiment of the present invention provides a wire posture prediction method based on inertial measurement technology, which calculates and predicts the wave length l of the wire dancing and the diameter d of the wire wave range (the dancing of the wire is simplified to a circle in this model) based on the inertial measurement technology, and establishes a wire posture prediction model image which is a shuttle shape as a whole according to the predicted wave length l of the wire dancing and the diameter d of the wire wave range. The overall length of the wire posture prediction model image is the predicted wire wave length l, the diameter of the shuttle middle position is the predicted diameter d of the wire wave range, and the dancing posture of the wire is located in the shuttle-shaped wire posture prediction model image.

[0049] The galloping of overhead wires is a self-excited process. When the movement frequency and movement distance of overhead wires increase, it can be considered that the wire galloping is spreading. At this time, the wave length l of the wire galloping will increase, and the diameter d of the wire wave range will also increase.

[0050] The wire attitude prediction method based on inertial measurement technology specifically includes the following steps:

[0051] S1. Obtain the function a(t) of the acceleration of the conductor in the vertical direction at the middle position and time, and calculate the frequency f of the function a(t) by Fourier transform method;

[0052] During the dancing of overhead wires, the frequency f1 of the overhead wire movement and the frequency f of the acceleration change on the overhead wire are consistent. The only difference is the time delay. Here, the frequency f of the function a(t) of acceleration and time is used as the frequency f1 of the predicted wire movement.

[0053] S2, predict the conductor wave length l according to formula ① and ②;

[0054] F(t)max-F(t)min=k(Ll)lM f(Ll)l-gl ①;

[0055] F(t)=a(t)*gl②;

[0056] In formulas ① and ②, L represents the length of the conductor between adjacent towers, g represents the deadweight of the conductor per unit length, k is a short-time constant (in the calculation of the same set of data, k is taken as a constant), f is the frequency of function a(t), and M represents the unit mass, M=1kg.

[0057] Den Hartog's vertical galloping theory believes that the condition for vertical vibration is that there is an upward component in the wind attack angle, which can be understood as a negatively damped free vibration. The wind acts on the ice-covered surface of the conductor to provide the conductor with an action in the same direction as the movement, which increases the vibration amplitude of the conductor and causes the system to be unstable for a long time, inducing galloping.

[0058] ⑥

[0059] In formula ⑥, is the atmospheric density, D is the ice diameter of the conductor perpendicular to the wind direction, U is the wind speed, C H is the aerodynamic coefficient along the direction (H is any direction with a vertical upward component), is the wind attack angle.

[0060] From formula ⑥, the wind acting on the ice-covered surface of the wire to provide a force in the same direction as the moving direction of the wire mainly depends on the environmental factors at the time of action. In a short period of time, the environmental factors can be considered as constants within a cycle of the acceleration and time function a(t). Here, k represents the continuous force (unit N / M) of the external force (wind assist) acting on the wire per unit area. 2 ).

[0061] (1) Take a section of the acceleration-time function a(t) that includes at least two peaks and two troughs, and calculate the frequency f of the predicted value function a(t) based on this section of the function.

[0062] Take the maximum value a(t)max of the function a(t) of acceleration and time in this section,

[0063] The minimum value a(t)min and the frequency f of the function a(t) of the obtained prediction amount are substituted into equations ① and ②.

[0064] (2) Next to the acceleration-time function a(t) taken above, take another acceleration-time function a(t) in the same way and substitute it into equations ① and ② in the same way.

[0065] Taking k as a constant, calculate the predicted conductor wave length l.

[0066] It is predicted that the conductor sweep length l increases as the frequency f of the a(t) function decreases and as the value of F(t)max-F(t)min increases.

[0067] S3, according to formula ③ predict the diameter d of the wire range;

[0068] ③;

[0069] In formula ③, t1 represents the moment when a(t)=0, and t2 represents the next moment when a(t)=0 after t1. Formula ③ calculates the displacement of the middle position of the wire within one cycle (time from t1 to t2).

[0070] S4. Establish a human-computer interactive wire posture prediction model image, the wire posture prediction model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d.

[0071] In one embodiment, the method further includes: obtaining a function a0(t) of acceleration of the conductor in the vertical direction at a measurement position other than the middle position and time;

[0072] According to formula ④, the diameter d0 of the wave range of the wire at the measurement position is predicted;

[0073] ④;

[0074] In formula ④, t5 represents the time when a0(t)=0, and t6 represents the next time when a0(t)=0 after t5.

[0075] Formula ④ calculates the displacement of the conductor at the measurement position that is not the middle position.

[0076] The wire posture prediction model image of human-computer interaction is corrected according to the predicted diameter d0 of the sweep range of the wire at the measurement position; specifically:

[0077] Taking the distance l0 between the acceleration sensor measuring the acceleration and time function a0(t) and the middle position of the wire as a reference, the diameter of the cross-sectional circle at the distance l0 from the middle position of the shuttle in the wire posture prediction model image is adjusted to d0.

[0078] In one embodiment, it further includes: two sets of weight-reducing anti-dancing devices are symmetrically installed on the conductor at a position L1 away from the middle position of the conductor.

[0079] When the overhead wire dances at a length L1 away from the middle position of the wire, it is not easy to produce violent dancing due to the influence of the weight anti-dancing device. The weight anti-dancing device can prevent the overhead wire located between the two sets of weight anti-dancing devices from dancing.

[0080] When the predicted wire sweep length l is greater than the distance L1 between the weight anti-dancing device and the middle position of the wire, that is, when the two sets of weight anti-dancing devices have been swept, the L1 distance is used as the overall length of the shuttle of the wire posture prediction model image, and the value of k(Ll)l is calculated. When k(Ll)l is greater than the preset threshold F 升 When the conductor is predicted to gallop severely, certain anti-galloping measures need to be taken.

[0081] In one embodiment, the specific method of obtaining the function a(t) of the acceleration of the wire in the vertical direction at the middle position and time in S1 is:

[0082] An inertial acceleration sensor is fixedly installed at the middle position of the wire;

[0083] A wireless gateway is installed on the power tower; the inertial acceleration sensor is connected to the wireless gateway on the power tower based on wireless ad hoc network technology, and the wireless gateway on the power tower collaboratively controls the inertial sensor through the ad hoc network to complete data collection and communication functions.

[0084] In one embodiment, the specific method of predicting the conductive line wave length l according to equations ① and ② in S2 is:

[0085] Obtain at least two segments of function a(t) within a preset time T, substitute function a(t) into equations ① and ② respectively, solve the roots of the equations, and obtain the predicted conductor sweep length l and short-time constant k;

[0086] k is a constant value within a time period less than the preset time T.

[0087] In one embodiment, the acceleration sequence acquired by the acceleration sensor is: n (n=1,2,3,...,N),t n ), and the objective function a(t) is obtained by fitting the trigonometric least squares method.

[0088] In one embodiment, the method further includes: obtaining a function a2(t) of the acceleration of the conductor in a non-vertical direction at the middle position and time,

[0089] According to formula ⑤, the diameter d2 of the wire coverage is predicted;

[0090] ⑤;

[0091] In formula ⑤, t3 represents the moment when a2(t)=0, and t4 represents the next moment when a2(t)=0 after t3;

[0092] Establishing a human-computer interactive wire posture prediction auxiliary model image, the wire posture prediction auxiliary model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d2;

[0093] The wire posture prediction model image and the wire posture prediction auxiliary model image are subjected to Boolean union operation to obtain the final wire posture model.

[0094] In one embodiment, the wire is predicted to be located at the outer contour position of the final wire posture model, and the wire randomly moves in the predicted model area. The most destructive mode is that the wire is located at the outer contour position of the final wire posture model.

[0095] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wire attitude prediction method based on inertial measurement technology, characterized in that: The following steps are involved: S1. Obtain the function a(t) of the acceleration of the conductor in the vertical direction at the middle position and time, and calculate the frequency f of the function a(t) by Fourier transform method; S2, predict the conductor wave length l according to formula ① and ②; F(t)max-F(t)min=k(Ll)lM f(Ll)l-gl ①; F(t)=a(t)*gl②; In formulas ① and ②, L represents the length of the conductor between adjacent towers, g represents the deadweight of the conductor per unit length, k is a short-time constant, f is the frequency of function a(t), and M represents the unit mass, M=1kg; S3, according to formula ③ predict the diameter d of the wire range; ③； In formula ③, t1 represents the moment when a(t)=0, and t2 represents the next moment when a(t)=0 after t1; S4. Establish a human-computer interactive wire posture prediction model image, the wire posture prediction model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d.

2. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 1, characterized in that: Also includes: Obtaining a function a0(t) of the acceleration of the conductor in the vertical direction at a measurement position other than the middle position and time; According to formula ④, the diameter d0 of the wave range of the wire at the measurement position is predicted; ④； In formula ④, t5 represents the moment when a0(t)=0, and t6 represents the next moment when a0(t)=0 after t5; The wire posture prediction model image of human-computer interaction is corrected according to the predicted diameter d0 of the sweep range of the wire at the measurement position; specifically: Taking the distance l0 between the acceleration sensor measuring the acceleration and time function a0(t) and the middle position of the wire as a reference, the diameter of the cross-sectional circle at the distance l0 from the middle position of the shuttle in the wire posture prediction model image is adjusted to d0.

3. The method for predicting the wire attitude based on inertial measurement technology according to claim 1 or 2, characterized in that: Also includes: Two sets of weight-weight anti-dancing devices are symmetrically installed on the conductor at a distance of L1 from the middle of the conductor; When the predicted wire sweep length l is greater than the distance L1 between the weight anti-dance device and the middle position of the wire, the L1 distance is used as the overall length of the shuttle of the wire posture prediction model image; and the value of k(Ll)l is calculated. When k(Ll)l is greater than the preset threshold F 升 When the load is too high, the wire is predicted to gallop severely.

4. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 1, characterized in that: The specific method of obtaining the function a(t) of the acceleration of the wire in the vertical direction at the middle position and time in S1 is: An inertial acceleration sensor is fixedly installed at the middle position of the wire; A wireless gateway is installed on the power tower; the inertial acceleration sensor is connected to the wireless gateway on the power tower based on wireless ad hoc network technology, and the wireless gateway on the power tower collaboratively controls the inertial sensor through the ad hoc network to complete data collection and communication functions.

5. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 1, characterized in that: The specific method of predicting the conductor wave length l according to equations ① and ② in S2 is: Obtain at least two segments of function a(t) within a preset time T, bring the function a(t) into equations ① and ② respectively, solve the roots of the equations, and obtain the predicted conductor sweep length l and short-time constant k; k is a constant value within a time period less than the preset time T.

6. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 4, characterized in that: The acceleration sequence acquired by the acceleration sensor is: n (n=1,2,3,...,N),t n ), and the objective function a(t) is obtained by fitting the trigonometric least squares method.

7. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 1, characterized in that: Also includes: Get the function a2(t) of the acceleration of the wire in the non-vertical direction at the middle position and time, According to formula ⑤, the diameter d2 of the wire coverage is predicted; ⑤； In formula ⑤, t3 represents the moment when a2(t)=0, and t4 represents the next moment when a2(t)=0 after t3; Establishing a human-computer interactive wire posture prediction auxiliary model image, the wire posture prediction auxiliary model image is a shuttle shape as a whole, the overall length is the predicted wire sweep length l, and the diameter of the shuttle middle position is the predicted wire sweep range diameter d2; The wire posture prediction model image and the wire posture prediction auxiliary model image are subjected to Boolean union operation to obtain the final wire posture model.

8. The method for predicting the guide wire attitude based on inertial measurement technology according to claim 7, characterized in that: The predicted wire is located at the outer contour position of the final wire posture model.

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