Pantograph lower guide rod load sensor, measurement system, measurement method and pantograph

Abstract

A pantograph lower guide rod load sensor, measurement system, measurement method, and pantograph are disclosed. The load sensor includes a sensor body having N load-bearing surfaces, each of which is integrated with a load chip, with the N load chips located on the same cross-sectional circumference. A stud is provided at one end of the sensor body, and a stud hole is provided at the other end of the sensor body, where N is an even number greater than or equal to 2. An embodiment of the present invention provides a pantograph lower guide rod load sensor capable of monitoring the stress and bending moment of the lower guide rod in real time during normal pantograph current collection operation, and determining whether the ball hinges at both ends of the lower guide rod are stuck based on the stress and bending moment.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a pantograph lower guide rod load sensor, a measurement system, a measurement method and a pantograph. Background Art

[0002] Subways are increasingly becoming a primary and efficient means of transportation in cities. Compared to other urban transportation options, subways offer significant benefits, including high capacity, roughly seven to ten times that of cars and buses, providing convenient transportation for residents. Furthermore, subways operate at high speeds, reaching speeds of up to 80 kilometers per hour, while intercity subways can reach speeds of up to 160 kilometers per hour, saving significant time. High-speed trains are powered by high-voltage electricity supplied by the trackside. This power is transmitted through the train's pantographs, which connect to the grid. The power system comprising the pantographs and catenary is called the pantograph-catenary system, which also controls the train's movement and stopping. Urban subway operations, particularly ensuring the proper functioning of the pantograph-catenary system, present significant challenges. This is because, during subway operation, the vibration of the pantograph and catenary causes the contact pressure between the pantograph and the catenary conductor to fluctuate randomly, resulting in an unstable contact pressure. If the center of gravity of the pantograph head is unbalanced or the rotation is not flexible at this time, the lower guide rod that assists the lower arm of the pantograph to lift the upper arm will be subjected to a large load. If the hinge system composed of the bearings at both ends of the lower guide rod of the pantograph is stuck, the four-bar linkage of the pantograph will lose the function of dynamically adjusting the height and balance of the pantograph head, and there is a risk of breakage of the lower guide rod and / or the ball joint.

[0003] In the prior art, there is a proposal to study the stress condition of the lower guide bar by directly adhering an electronic strain gauge to the surface of the lower guide bar. However, since this is a non-live operation and the driving speed is slow, it cannot truly reflect the load state of the lower guide bar during actual driving of the electric passenger car.

[0004] Therefore, there is an urgent need for a sensor product that can monitor the stress and bending moment of the lower guide rod in real time when the pantograph of the pantograph-net system is in normal current-collecting working condition. Summary of the Invention

[0005] An embodiment of the present invention provides a pantograph lower guide rod load sensor, which can monitor the stress and bending moment of the lower guide rod in real time when the pantograph is in normal current collecting working state, and judge whether the spherical hinges at both ends of the lower guide rod are stuck through the stress and bending moment.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a pantograph lower guide rod load sensor, the pantograph includes a four-bar structure, the four-bar structure includes a lower guide rod, and the load sensor includes a sensor body; the sensor body has N force-bearing surfaces, each force-bearing surface is integrated with a load chip, the N load chips are located on the same cross-sectional circumference, one end of the sensor body is provided with a stud, and the other end of the sensor body is provided with a stud hole, and N is an even number greater than or equal to 2.

[0007] Optionally, the sensor body has four force-bearing surfaces, two relative force-bearing surfaces are parallel to the plane of the four-bar linkage structure, and the other two relative force-bearing surfaces are perpendicular to the plane of the four-bar linkage structure.

[0008] Optionally, the sensor body further comprises a fiber guide groove; the fiber guide groove is arranged on a side of each force-bearing surface close to the stud hole, and the optical fiber pigtail of each load chip is led out through the fiber guide groove.

[0009] Optionally, the pantograph lower guide rod load sensor further includes: a sensor cover, the sensor cover is provided with a fiber optic pigtail plug corresponding to the fiber lead slot, and the fiber optic pigtails of each load chip pass through the fiber optic pigtail plug.

[0010] Optionally, the pantograph lower guide rod load sensor according to claim 1 is characterized in that the sensor body also includes a sealing cover plate, the sealing cover plate is arranged on a side close to the stud, and a plurality of first bolt holes are provided on the sealing cover plate; the load sensor also includes a sensor cover, the sensor cover has a cover plate surface, and the cover plate surface is provided with second bolt holes corresponding to the plurality of first bolt holes.

[0011] Optionally, the sensor body further includes a cover plate sealing ring, which is arranged at a connection position between the sealing cover plate and the cover plate surface of the sensor housing.

[0012] Optionally, the sensor body further includes a sealing ring, which is arranged on a side close to the stud hole; the load sensor further includes a sensor cover, which is inserted into the sensor body via the sealing ring.

[0013] Optionally, the integration method of the payload chip is selected from: screw fastening, embedding, welding, gluing and implanting.

[0014] An embodiment of the present invention also discloses a method for measuring the state of the pantograph lower guide rod based on the pantograph lower guide rod load sensor, wherein the load sensor is integrally connected to the lower guide rod through a stud hole and a stud, and the measurement method includes: obtaining the initial measurement value of each load chip when the lower guide rod is unloaded, and the current measurement value of each load chip; determining the tension, bending moment and / or ball joint stuck state of the lower guide rod at the current moment based on at least the change between the current measurement value of each load chip and the initial measurement value.

[0015] Optionally, the current measurement value includes a current wavelength value and a current temperature value, and the initial measurement value includes an initial wavelength value and an initial temperature value. The determining of the tension of the lower guide rod at the current moment based at least on the change between the current measurement value of each load chip and the initial measurement value includes: calculating the wavelength difference between the current wavelength value of each load chip and the initial wavelength value, and the temperature difference between the current temperature value and the initial temperature value of each load chip; calculating the tension change value using the wavelength difference, and calculating the temperature compensation value using the temperature difference; calculating the sum of the tension change value of each load chip and the temperature compensation value as the tension of the lower guide rod at the current moment.

[0016] Optionally, the tension is calculated using the following formula: Among them, F pf (t) is used to represent the tension value of the lower guide rod at time t, N is used to represent the total number of the load chips, K pf,n It is used to represent the tension coefficient of the nth load chip, λn(t) is used to represent the wavelength value of the nth load chip at time t, λ0,n is used to represent the wavelength value of the nth load chip when it is unloaded, kT,n is used to represent the temperature drift coefficient of the nth load chip, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial moment.

[0017] Optionally, the following formula is used to calculate the bending moment of the lower guide rod at the current moment: M i,i-opp (t) = K M,i {λ i (t)-λ 0,i +k T,i [T(t)-T0]}-K M-opp,i-opp {λ opp,i-opp (t)-λ 0-opp,i-opp +k T-opp,i-opp [T(t)-T0]}, where i=1,2,3,…,I, Where Mi,i-opp(t) is used to represent the bending moment value of the lower guide rod in the i,i-opp bending direction at time t, N is used to represent the total number of load chips, I is used to represent the number of pairs of two load chips facing each other on the same cross section of the lower guide rod, and K M,i It is used to represent the bending moment coefficient of the i-th load sensor of the lower guide rod, λi(t) is used to represent the wavelength value of the i-th load chip at time t, λ0,i is used to represent the wavelength value of the i-th load chip when there is no load, kT,i is used to represent the temperature drift coefficient of the i-th load chip, K M-opp,i-opp It is used to express the bending moment coefficient of the load chip that the i-th load chip of the lower guide rod is facing, λ opp,i-opp (t) is used to represent the wavelength value of the i-opp load chip facing the i-th load chip at time t, λ 0-opp,i-opp It is used to indicate the wavelength value of the i-opp load chip facing the i-th load chip when there is no load, k T-opp,i-opp It is used to represent the temperature drift coefficient of the i-opp load chip directly opposite to the i-th load chip, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial time.

[0018] Optionally, the method of determining the ball joint stuck state of the lower guide rod at the current moment based on at least the change between the current measurement value of each load chip and the initial measurement value includes: calculating the stuck tension value and the stuck bending moment value of the pantograph bow head at different heights according to the maximum driving torque value of the pantograph lower arm, and the spherical hinge shafts at both ends of the lower guide rod are completely stuck at the stuck tension value and the stuck bending moment value; comparing the tension at the current moment with the stuck tension value, and comparing the bending moment at the current moment with the stuck bending moment value; when the tension at the current moment is greater than the stuck tension value, and the bending moment at the current moment is greater than the stuck bending moment value, it is determined that the spherical hinge shafts at both ends of the lower guide rod are in a stuck state.

[0019] Optionally, the method further includes: after determining that the spherical hinge shafts at both ends of the lower guide rod are in a stuck state, determining the bending direction of the lower guide rod according to the positive or negative value of the bending moment at the current moment.

[0020] Optionally, determining the bending direction of the lower guide rod based on the positive or negative value of the bending moment at the current moment includes: when the bending moment at the current moment is positive, determining that the middle portion of the lower guide rod protrudes into the four-bar linkage frame; when the bending moment at the current moment is negative, determining that the middle portion of the lower guide rod protrudes out of the four-bar linkage frame.

[0021] An embodiment of the present invention further discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the pantograph lower guide rod state measurement method are executed.

[0022] An embodiment of the present invention also discloses a pantograph lower guide rod state measurement system, which includes: the pantograph lower guide rod load sensor, used to receive optical signals; and a processor, coupled to the load sensor, used to process the signal collected by the load sensor.

[0023] An embodiment of the present invention also discloses a pantograph, which includes a pantograph lower guide rod load sensor and a four-bar structure; the four-bar structure includes a lower guide rod, one end of the lower guide rod is provided with a stud hole, and the other end of the lower guide rod is provided with a spherical hinge, the stud of the sensor body is screwed to the bolt hole of the lower guide rod, and the stud hole of the sensor body is screwed to the spherical hinge of the lower guide rod.

[0024] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0025] In the technical solution of the present invention, the load sensor includes a sensor body; the sensor body has N load-bearing surfaces, each of which is integrated with a load chip, and the N load chips are located on the same cross-sectional circumference. A stud is provided at one end of the sensor body, and a stud hole is provided at the other end of the sensor body, where N is an even number greater than or equal to 2. In the technical solution of the present invention, the load chip is integrated with the load-bearing surface, so that the load chip and the load-bearing surface become one, and the sensor body can be connected to the lower guide rod through the studs and bolt holes on both sides, so that the load sensor as a whole becomes one with the lower guide rod of the pantograph, thereby enabling the sensor to monitor the load state of the lower guide rod in real time during the normal current collection working state of the pantograph, thereby realizing monitoring and maintenance of the working state of the lower guide rod. In addition, the load sensor of the technical solution of the present invention can be installed and separated from the lower guide rod, and can be applied to the lower guide rods of pantographs of various structures and types without affecting the production, installation, and maintenance of the pantograph, thus realizing convenient sensor application.

[0026] Furthermore, by integrating the load sensor on the lower guide rod of the pantograph to measure and calculate the tension and bending moment of the lower guide rod in real time, and identifying the jamming condition of the spherical hinges at both ends of the lower guide rod, more detailed monitoring and maintenance of the lower guide rod status can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a pantograph lower guide rod load sensor according to an embodiment of the present invention;

[0028] Figure 2This is a schematic structural diagram of a pantograph lower guide rod load sensor according to an embodiment of the present invention;

[0029] Figure 3 This is a cross-sectional schematic diagram of an embodiment of the present invention after the force-bearing surface and the load chip are integrated;

[0030] Figure 4 This is a schematic structural diagram of a sensor cover according to an embodiment of the present invention;

[0031] Figure 5 1 is a schematic structural diagram of a four-bar linkage structure according to an embodiment of the present invention;

[0032] Figure 6 1 is a cross-sectional schematic diagram of a load sensor connected to a lower guide rod according to an embodiment of the present invention;

[0033] Figure 7 Schematic diagram of the position of a load chip on the same circumferential cross section of a lower guide rod in an embodiment of the present invention;

[0034] Figure 8 Schematic diagram of a measurement method in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] As described in the background technology, there is an urgent need for a sensor product that can monitor the stress and bending moment of the lower guide rod in real time when the pantograph of the pantograph-catenary system is in normal current-collecting working state.

[0036] In the technical solution of the present invention, the load chip is integrated with the load-bearing surface, forming a single unit. The sensor body can be connected to the lower guide rod via studs and bolt holes on both sides, integrating the load sensor with the pantograph's lower guide rod. This allows the sensor to monitor the stress state of the lower guide rod in real time during the pantograph's normal current-collecting operation, enabling monitoring and maintenance of the lower guide rod's operating status. Furthermore, the load sensor of the technical solution of the present invention can be installed and detached from the lower guide rod without affecting the production, installation, and maintenance of the pantograph, thus facilitating convenient sensor application.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] Figure 1 and Figure 2 It is a structural schematic diagram of a pantograph lower guide rod load sensor according to an embodiment of the present invention.

[0039] Figure 1 and Figure 2 A specific structure of the load sensor is shown from different angles. Figure 1As shown, the load sensor includes a sensor body, which has four load-bearing surfaces: load-bearing surface 1.1, load-bearing surface 1.2, load-bearing surface 1.3, and load-bearing surface 1.4. Each load-bearing surface is integrated with a load-sensitive chip (not shown), also known as a load chip. The four load chips are located on the same cross-sectional circumference.

[0040] It should be noted that a plurality of load chips may be installed in pairs at relative positions on any circumferential cross section of the lower guide rod, and the embodiment of the present invention does not impose any limitation on this.

[0041] In a specific implementation, the load chip and the load-bearing surface are integrated in a manner selected from: screw fastening, embedding, welding, gluing and implanting.

[0042] A stud 3 is provided at one end of the sensor body, and a stud hole 2 is provided at the other end of the sensor body.

[0043] Correspondingly, in the pantograph's lower guide rod structure, one end of the lower guide rod is provided with a stud hole, and the other end of the lower guide rod is provided with a spherical hinge. The stud 3 of the sensor body is screwed into the bolt hole of the lower guide rod, and the stud hole 2 of the sensor body is screwed into the spherical hinge of the lower guide rod. As a result, the load sensor and the lower guide rod form an integrated structure. As the lower guide rod moves, the load sensor also moves with it, enabling the load sensor to more accurately measure the stress and bending moment of the lower guide rod.

[0044] Combined with reference Figure 5 , Figure 5 The figure shows a schematic diagram of a four-bar linkage structure according to an embodiment of the present invention, wherein the four-bar linkage structure may include a lower guide rod 322, a lower arm 324, and an upper arm 323, and may also include a first connecting shaft 331, a second connecting shaft 332, a third connecting shaft 333, and a fourth connecting shaft 334.

[0045] The connecting axis may be a hinge axis, such as a spherical hinge axis.

[0046] The first connecting shaft 331 can be used to connect the lower arm 324 and the base frame 321, the second connecting shaft 332 can be used to connect the lower guide rod 322 and the base frame 321, the third connecting shaft 333 can be used to connect the lower guide rod 322 and the upper arm 323, and the fourth connecting shaft 334 can be used to connect the lower arm 324 and the upper arm 323.

[0047] In the four-bar linkage of the pantograph, the distance between each axis is constant, and the internal angle and shape of the four-bar linkage depend on the pantograph's lifting working height.

[0048] The load sensor of the embodiment of the present invention can be integrated with the lower guide rod 322. The stud 3 of the sensor body is screwed to the bolt hole of the lower guide rod 322, and the stud hole 2 of the sensor body is screwed to the spherical hinge of the lower guide rod 322. The cross-sectional diagram after the load sensor and the lower guide rod 322 are integrated can be referred to. Figure 6 .

[0049] like Figure 6 As shown, load chips U1, U2, U3, and U4 (not shown) are located on the same cross-sectional circumference. The sensing directions of the four load chips are integrated along the length of the lower guide rod 322 and are located on the outer wall of the lower guide rod near the second connecting axis 332. The second connecting axis 332 represents the hinge axis at one end of the lower guide rod.

[0050] It should be noted that, in a specific implementation, the sensor body may also be provided with any other feasible number of force-bearing surfaces, such as 6 force-bearing surfaces, 8 force-bearing surfaces, etc., and the embodiment of the present invention does not limit this.

[0051] In a non-limiting embodiment of the present invention, when the sensor body includes four load-bearing surfaces, two relative load-bearing surfaces are parallel to the plane of the four-bar linkage structure, and the other two relative load-bearing surfaces are perpendicular to the plane of the four-bar linkage structure. For example, load-bearing surfaces 1.1 and 1.3 are perpendicular to the plane of the four-bar linkage structure, while load-bearing surfaces 1.2 and 1.4 are parallel to the plane of the four-bar linkage structure, and the areas of load-bearing surfaces 1.1 and 1.3 are smaller than the areas of load-bearing surfaces 1.2 and 1.4, so as to better identify the stuck state of the spherical hinge shaft at both ends of the lower guide rod in subsequent steps. Then, the tension of the lower guide rod can be calculated using the load chip on each load-bearing surface, the longitudinal bending moment of the lower guide rod can be calculated using the load chip on the load surfaces 1.1 and 1.3, and the lateral bending moment of the lower guide rod can be calculated using the load chip on the load surfaces 1.2 and 1.4.

[0052] Please refer to the Figure 3 The load chip U1 is integrated on the force surface 1.1, the load chip U2 is integrated on the force surface 1.2, the load chip U3 is integrated on the force surface 1.3, and the load chip U4 is integrated on the force surface 1.4. The areas of the force surfaces 1.1 and 1.3 are smaller than the areas of the force surfaces 1.2 and 1.4. Among them, the load chip U1 and the load chip U3 are opposite chips, and the load chip U2 and the load chip U4 are opposite chips.

[0053] In a specific implementation, the load chip can be a fiber optic sensor chip, for example, a fiber optic stress chip with temperature compensation function. Furthermore, the fiber optic sensor chip can be selected from: micro-electro-mechanical system (MEMS) fiber optic sensor, micro-opto-electro-mechanical system (MOEMS) fiber optic sensor, and micro-opto-mechanical system (MOMS) fiber optic sensor.

[0054] Take MEMS fiber optic sensors, for example. MEMS fiber optic sensing technology is a 21st-century cutting-edge technology based on micron / nanomechanics and optics. This technology integrates the mass, elastic support, optical reflective micromirrors, and light input and output waveguide systems directly on a tiny chip, enabling all-optical detection and transmission of signals such as vibration, pressure, current, and temperature. The resulting MEMS chip boasts a compact structure, integrated packaging, and excellent parameter consistency, high sensitivity, a wide dynamic range, excellent linearity, and stable and reliable performance.

[0055] The silicon-based sensitive structure of a MEMS chip is manufactured using micro-electromechanical (MEMS) technology, and signals are detected and read using fiber optic detection technology. Thus, it combines the advantages of both MEMS and fiber optic sensing technologies. Furthermore, MEMS fiber optic sensing technology overcomes the constraints of existing sensing technologies, which often require wide bandwidth and high precision. It is passive, has a wide temperature range, is miniaturized, resists electromagnetic interference, is lightweight, easily networked, and requires no maintenance. Therefore, it enables long-term, accurate measurement and reduces the complexity and cost of smart operations and maintenance systems. Therefore, MEMS fiber optic sensing technology is ideally suited for real-time monitoring of vehicle pantographs, contact wires, and their relationships.

[0056] It should be noted that the MOEMS optical fiber sensor and the MOMS optical fiber sensor in the embodiments of the present invention can have the advantages of the above-mentioned MEMS optical fiber sensor.

[0057] It should be noted that the MEMS fiber optic load sensor can be replaced by other single-point or / and integrated optical sensors (such as fiber grating FBG) or / and electronic sensors (such as resistance strain gauges) that use optical fiber as perception or transmission, and the embodiments of the present invention do not limit this.

[0058] Continue to refer to Figure 1 and Figure 2The sensor body also includes a fiber guide groove, which is provided on one side of each force-bearing surface close to the stud hole 2. The optical fiber pigtail of each load chip is led out through the fiber guide groove. The function of the fiber guide groove is to better collect the optical fiber pigtails. Specifically, the force-bearing surface 1.1 is provided with a fiber guide groove 5.1, and the optical fiber pigtail of the load chip U1 on the force-bearing surface 1.1 is led out through the fiber guide groove 5.1. Each force-bearing surface is provided with a fiber guide groove (not shown in the figure).

[0059] Further, please refer to Figure 4 The load sensor also includes a sensor housing, which is equipped with a fiber pigtail plug 7 corresponding to the fiber lead slot. The fiber pigtails of each load chip are passed through the fiber pigtail plug. Specifically, the fiber pigtails are led out through the fiber lead slot, bundled, and then passed through the fiber pigtail plug 7 on the sensor housing. The sensor housing is used to cover the outside of the sensor body to achieve dust and water protection.

[0060] Continue to refer to Figure 1 、 Figure 2 and Figure 4 The sensor body also includes a sealing cover plate 4, positioned near the studs. The sealing cover plate is provided with a plurality of first bolt holes. Accordingly, the sensor cover has a cover plate surface 8, which is provided with second bolt holes corresponding to the plurality of first bolt holes. Screws are passed through the first and second bolt holes, tightening them to secure the sensor body and the sensor cover together, completing the packaging of the load sensor. Specifically, the sealing cover plate 4 is disc-shaped and has four first bolt holes for docking with the sensor cover.

[0061] Furthermore, the sensor body includes a cover plate sealing ring 4.1, which is disposed at the connection between the sealing cover plate 4 and the cover plate surface 8 of the sensor housing. By connecting the sealing cover plate 4 of the sensor body and the cover plate surface 8 of the sensor housing with the cover plate sealing ring 4.1, the sensor can be better protected from dust and water.

[0062] Continue to refer to Figure 1 and Figure 2 The sensor body also includes a sealing ring 6.1 and a sealing ring 6.2, which are positioned near the stud hole 2. The load sensor also includes a sensor cover, which is inserted into the sensor body via the sealing rings. The sealing rings 6.1 and 6.2 provide better dust and water protection for the sensor cover after it is inserted into the sensor body.

[0063] In a specific application scenario of the present invention, eight load chips may be provided in the load sensor, and accordingly, the sensor body of the load sensor includes eight load-bearing surfaces. Figure 7 As shown, the eight load chips are installed in pairs at relative positions on any circumferential cross-section of the lower guide rod. For example, load chip numbered n=1 is located at end 1, opposite load chip numbered n=5, located at end 1-opp. Similarly, load chip numbered n=2 is located at end 2, opposite load chip numbered n=6, located at end 2-opp. Load chip numbered n=3 is located at end 3, opposite load chip numbered n=7, located at end 3-opp. Load chip numbered n=4 is located at end 4, opposite load chip numbered n=8, located at end 4-opp. End 1, end 1-opp, end 2, end 2-opp, end 3, end 3-opp, end 4, and end 4-opp are located on the eight force-bearing surfaces of the sensor body, respectively.

[0064] Please refer to Figure 8 The embodiment of the present invention further discloses a method for measuring the state of the pantograph lower guide rod, and the measuring method may include the following steps:

[0065] Step S801: acquiring an initial measurement value of each load chip when the lower guide rod is unloaded, and a current measurement value of each load chip;

[0066] Step S802: determining the tension, bending moment and / or ball joint stuck state of the lower guide rod at the current moment based on at least the variation between the current measurement value of each load chip and the initial measurement value.

[0067] It should be noted that the serial numbers of the steps in this embodiment do not limit the execution order of the steps.

[0068] In this embodiment, the signal of the load chip can be used to indicate the tension of the lower guide rod. Based on the comparison results of the tension when there is a load on the lower guide rod and the tension when there is no load, it can be determined whether the current tension of the lower guide rod is within the normal tolerance range. The measurement of the tension of the lower guide rod can be the sum of the changes in the forces of the four optical fiber stress chips when there is a load compared to when there is no load. It should be noted that, taking a non-restrictive pantograph as an example, the maximum tension value at both ends of the lower guide rod can be 10,000N, and the tension value of the lower guide rod under normal operation can be 7,000N to 8,000N.

[0069] In a non-limiting embodiment of the present invention, Figure 8The shown step S802 may include the following steps: calculating the wavelength difference between the current wavelength value of each load chip and the initial wavelength value, and the temperature difference between the current temperature value of each load chip and the initial temperature value; using the wavelength difference to calculate the tension change value, and using the temperature difference to calculate the temperature compensation value; calculating the sum of the tension change value and the temperature compensation value of each load chip as the tension of the lower guide rod at the current moment.

[0070] Furthermore, the tension can be calculated using the following formula: Among them, F pf (t) is used to represent the tension value of the lower guide rod at time t, N is used to represent the total number of the load chips, K pf,n Used to express the tension coefficient of the nth load chip, λ n (t) is used to represent the wavelength value of the nth load chip at time t, λ 0,n Used to indicate the wavelength value of the nth load chip when it is unloaded, k T,n It is used to represent the temperature drift coefficient of the nth optical fiber load sensor, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial time.

[0071] In a specific embodiment, combining Figure 3 For the sensor structure shown, when the total number of load chips is 4, the tension can be calculated using the following formula: Alternatively, the above formula can be transformed into

[0072] It should be noted that the tension coefficient K pf,n And the temperature drift coefficient k T,n It can be pre-calibrated, the wavelength value λ of the load chip when it is unloaded 0,n The temperature value T0 at the initial moment may be obtained by pre-measurement. The embodiment of the present invention does not limit the specific calibration method and the specific measurement method.

[0073] In a non-limiting embodiment of the present invention, for the bending moment monitoring of the lower guide rod, a load sensor structure for monitoring the tension of the lower guide rod can also be set, and then it can be determined whether the current bending moment of the lower guide rod is within the normal bearing range based on the comparison results of the bending moments when there is load and when there is no load on the lower guide rod.

[0074] Specifically, the load sensors can be installed in pairs on the same cross-sectional circumference of any cross-section of the lower guide rod, and the paired load sensors can be centrally symmetrical. The load signal of the load chip is used to indicate the bending moment of the lower guide rod.

[0075] Specifically, the following formula is used to calculate the bending moment of the lower guide rod at the current moment: Mi,i-opp (t) = K M,i {λ i (t)-λ 0,i +k T,i [T(t)-T0]}-K M-opp,i-opp {λ opp,i-opp (t)-λ 0-opp,i-opp +k T-opp,i-opp [T(t)-T0]}, where i=1,2,3,…,I, Among them, M i,i-opp (t) is used to represent the bending moment value of the lower guide rod in the i-th, i-opp bending direction at time t, N is used to represent the total number of the load chips, I is used to represent the number of pairs of two load chips facing each other on the same cross section of the lower guide rod, K M,i Used to represent the bending moment coefficient of the i-th load sensor of the lower guide rod, λ i (t) is used to represent the wavelength value of the i-th optical fiber load sensor at time t, λ 0,i Used to represent the wavelength value of the i-th load chip when there is no load, k T,i Used to represent the temperature drift coefficient of the i-th load chip, K M-opp,i-opp It is used to express the bending moment coefficient of the load chip that the i-th load chip of the lower guide rod is facing, λ opp,i-opp (t) is used to represent the wavelength value of the i-opp load chip facing the i-th load chip at time t, λ 0-opp,i-opp It is used to indicate the wavelength value of the i-opp load chip facing the i-th load chip when there is no load, k T-opp,i-opp It is used to represent the temperature drift coefficient of the i-opp load chip directly opposite to the i-th load chip, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial time.

[0076] It should be noted that the bending moment coefficient K M,i And the bending moment coefficient K M-opp,i-opp It can be pre-calibrated. The embodiment of the present invention does not limit the specific calibration method.

[0077] In a non-limiting embodiment of the present invention, in conjunction with reference to Figure 5 Because the first, second, third, and fourth connecting shafts 331, 332, 333, and 334 all rotate, the internal angle and shape of the four-bar linkage change with the height of the pantograph head. When force is applied to the upper arm 323, lower arm 324, and lower guide rod 322, they may become stuck, for example, making it difficult to restore the structure after bending.

[0078] In an embodiment of the present invention, the stuck tension value and stuck bending moment value of the pantograph bow head at different heights can be calculated respectively according to the maximum driving torque value of the pantograph lower arm, and the spherical hinge shafts at both ends of the lower guide rod are completely stuck at the stuck tension value and the stuck bending moment value; the tension at the current moment is compared with the stuck tension value, and the bending moment at the current moment is compared with the stuck bending moment value; when the tension at the current moment is greater than the stuck tension value, and the bending moment at the current moment is greater than the stuck bending moment value, it is determined that the spherical hinge shafts at both ends of the lower guide rod are in a stuck state.

[0079] Specifically, when the bending moment at the current moment is positive, it is determined that the middle portion of the lower guide rod protrudes into the four-bar linkage frame; when the bending moment at the current moment is negative, it is determined that the middle portion of the lower guide rod protrudes out of the four-bar linkage frame.

[0080] In practice, the pantograph height can operate within a certain range, for example, between 350 mm and 2500 mm. First, the lengths of the base frame 321, lower guide rod 322, lower arm 324, and upper arm 323 (i.e., L1, L2, L3, and L4) can be measured, as well as the distance L5 from the torque center of the lower guide rod load sensor to axis 332. L6 is the line connecting axis 332 and axis 334. Next, the internal angles α1, α2, β, θ1, and θ2 of the four-bar linkage are measured at different heights (e.g., 50 mm increments) in a naturally raised state without pressure from the contact line on the pantograph head. α1 is defined as the angle between L4 and L6, α2 as the angle between L2 and L6, β as the angle between L1 and L4, θ1 as the angle between L3 and L4, and θ2 as the angle between L2 and L3.

[0081] Based on the maximum driving torque of the pantograph lower arm—the maximum torque for rotation about axis 331, for example, 1500 N×m or 2000 N×m, depending on the pantograph type—the established model and algorithm calculate the corresponding stuck tension and stuck bending moment values at the lower guide rod load sensor when the spherical hinge axis 332 or axis 333 at each end of the lower guide rod is completely stuck and unable to rotate, at different pantograph head heights. Finally, by combining the real-time tension and bending moment values measured by the lower guide rod load sensor and comparing them with its own stuck tension and stuck bending moment values, it is possible to identify in real time whether the spherical hinge axes at each end of the lower guide rod, namely the second connecting axis 332 and the third connecting axis 333, are stuck, providing an immediate warning. In addition, the positive and negative values of the bending moment values at the lower guide rod load sensor can be used to determine the bending direction of the middle portion of the lower guide rod, and to distinguish whether the second connecting shaft 332 or the third connecting shaft 333 is stuck. That is, when the middle portion of the lower guide rod protrudes into the four-bar mechanism frame, the bending moment at the lower guide rod load sensor is positive, and the second connecting shaft 332 is stuck at this time; conversely, when the middle portion of the lower guide rod protrudes out of the four-bar mechanism frame, the bending moment at the lower guide rod load sensor is negative, and the third connecting shaft 333 is stuck at this time.

[0082] In a specific application scenario, the specific values of the internal angle, stuck tension value and stuck bending moment value of the four-bar linkage at different heights of the pantograph head can be referred to Table 1.

[0083] Table 1

[0084]

[0085]

[0086] In a specific implementation, for example, when the bow height is 2400 mm, the real-time tensile force measured by the lower guide rod load sensor is compared with the sticking tensile force value of shaft 332, and the real-time bending moment value is compared with the sticking bending moment value of shaft 332 to determine whether shaft 332 is stuck. Accordingly, at other bow heights, the real-time data measured by the load sensor is compared with the sticking tensile force and sticking bending moment values corresponding to the bow height, which will not be further described here.

[0087] The measurement method referred to in the embodiment of the present invention can be executed by a processor, which can also be a central processing unit (CPU), other general-purpose processors, DSPs, application-specific integrated circuits (ASICs), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0088] The embodiment of the present invention further discloses a pantograph lower guide rod state measurement system, the measurement system comprising:

[0089] The pantograph lower guide rod load sensor is used to receive optical signals;

[0090] The processor is coupled to the load sensor and is used to process the signal collected by the load sensor.

[0091] The measurement system of the embodiment of the present invention can monitor the tension, bending moment and stuck state of the pantograph lower guide rod, assist the user in maintaining the state of the lower guide rod, and ensure the normal operation of the pantograph.

[0092] An embodiment of the present invention also discloses a pantograph, which includes a pantograph lower guide rod load sensor and a four-bar structure; the four-bar structure includes a lower guide rod, one end of the lower guide rod is provided with a stud hole, and the other end of the lower guide rod is provided with a spherical hinge, the stud of the sensor body is screwed to the bolt hole of the lower guide rod, and the stud hole of the sensor body is screwed to the spherical hinge of the lower guide rod.

[0093] The lower guide rod load sensor in the embodiments of the present invention is interconnected with the lower guide rod as an independent, easily installed, and removable device. The lower guide rod load sensor is integrated with the pantograph's lower guide rod, and a load chip can be integrated at the center of the sensor's load-bearing surface, integrating the load chip with the sensor's load-bearing surface and enabling the load chip to directly sense changes in tension and bending moment on the lower guide rod. Furthermore, the lower guide rod load sensor can be integrated and installed on any lower guide rod without affecting the production, installation, and maintenance of the pantograph.

[0094] For more information on the working principle and working mode of the measurement method, please refer to Figures 1 to 7 The relevant description in will not be repeated here.

[0095] The embodiment of the present invention further discloses a storage medium, which is a computer-readable storage medium having a computer program stored thereon. When the computer program is run, the computer program can execute Figure 3The steps of the access control method shown in . The memory in the embodiment of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0096] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A pantograph lower guide rod load sensor, characterized in that: The load sensor includes a sensor body; The sensor body has N force-bearing surfaces, each of which is integrated with a load chip, and the N load chips are located on the same cross-sectional circumference. A stud is provided at one end of the sensor body, and a stud hole is provided at the other end of the sensor body. N is an even number greater than or equal to 2. The pantograph includes a four-link structure, and the four-link structure includes the pantograph lower guide rod, One end of the pantograph lower guide rod is provided with a stud hole, and the other end of the pantograph lower guide rod is provided with a spherical hinge, the stud of the sensor body is screwed to the bolt hole of the pantograph lower guide rod, and the stud hole of the sensor body is screwed to the spherical hinge of the pantograph lower guide rod; The sensor body has four force-bearing surfaces, two of which are parallel to the plane of the four-bar linkage structure, and the other two are perpendicular to the plane of the four-bar linkage structure; The areas of the two relative force-bearing surfaces perpendicular to the plane of the four-bar linkage structure are smaller than the areas of the two relative force-bearing surfaces parallel to the plane of the four-bar linkage structure.

2. The pantograph lower guide rod load sensor according to claim 1, characterized in that: The sensor body further includes a fiber guide groove; The fiber guide groove is arranged on one side of each force-bearing surface close to the stud hole, and the optical fiber pigtail of each load chip is led out through the fiber guide groove.

3. The pantograph lower guide rod load sensor according to claim 2, characterized in that: Also includes: The sensor cover is provided with an optical fiber pigtail plug corresponding to the fiber lead slot, and the optical fiber pigtail of each load chip passes through the optical fiber pigtail plug.

4. The pantograph lower guide rod load sensor according to claim 1, characterized in that: The sensor body further includes a sealing cover plate, which is arranged on a side close to the stud and has a plurality of first bolt holes formed thereon; The load sensor further includes a sensor cover having a cover plate surface, wherein the cover plate surface is provided with second bolt holes corresponding to the plurality of first bolt holes.

5. The pantograph lower guide rod load sensor according to claim 4, characterized in that: The sensor body further comprises a cover plate sealing ring, which is arranged at a connection position between the sealing cover plate and the cover plate surface of the sensor housing.

6. The pantograph lower guide rod load sensor according to claim 1, characterized in that: The sensor body further includes a sealing ring, which is arranged on a side close to the stud hole; the load sensor further includes a sensor cover, which is inserted into the sensor body via the sealing ring.

7. The pantograph lower guide rod load sensor according to any one of claims 1 to 6, characterized in that: The integration method of the payload chip is selected from the group consisting of: screw fastening, embedding, welding, pasting and implanting.

8. A method for measuring the state of a pantograph lower guide rod based on the pantograph lower guide rod load sensor according to any one of claims 1 to 7, characterized in that: The load sensor is integrally connected to the lower guide rod through a stud hole and a stud, and the measuring method includes: Obtaining an initial measurement value of each load chip when the lower guide rod is unloaded, and a current measurement value of each load chip; Determining the tension, bending moment and / or ball joint stuck state of the lower guide rod at a current moment based on at least a change between a current measurement value of each load chip and the initial measurement value; The determining of the ball joint stuck state of the lower guide rod at the current moment based on at least the amount of change between the current measurement value of each load chip and the initial measurement value includes: According to the maximum driving torque value of the pantograph lower arm, the stuck tension value and the stuck bending moment value of the pantograph head at different heights are calculated respectively, and the spherical hinge shafts at both ends of the lower guide rod are completely stuck under the stuck tension value and the stuck bending moment value; Comparing the tension at the current moment with the stuck tension value, and comparing the bending moment at the current moment with the stuck bending moment value; When the pulling force at the current moment is greater than the stuck pulling force value, and the bending moment at the current moment is greater than the stuck bending moment value, it is determined that the spherical hinge shafts at both ends of the lower guide rod are in a stuck state.

9. The method for measuring the state of the pantograph lower guide rod according to claim 8, characterized in that: The current measurement value includes a current wavelength value and a current temperature value, the initial measurement value includes an initial wavelength value and an initial temperature value, and determining the tension of the lower guide rod at the current moment based on at least a change between the current measurement value of each load chip and the initial measurement value includes: Calculating a wavelength difference between a current wavelength value of each payload chip and the initial wavelength value, and a temperature difference between a current temperature value of each payload chip and the initial temperature value; Calculating a tension change value using the wavelength difference, and calculating a temperature compensation value using the temperature difference; The sum of the tension change value of each load chip and the temperature compensation value is calculated as the tension of the lower guide rod at the current moment.

10. The method for measuring the state of the pantograph lower guide rod according to claim 8, characterized in that: The pulling force is calculated using the following formula: , where F pf (t) is used to represent the tension value of the lower guide rod at time t, N is used to represent the total number of the load chips, K pf,n It is used to represent the tension coefficient of the nth load chip, λn(t) is used to represent the wavelength value of the nth load chip at time t, λ0,n is used to represent the wavelength value of the nth load chip when there is no load, and k T,n It is used to represent the temperature drift coefficient of the nth load chip, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial time.

11. The method for measuring the state of the pantograph lower guide rod according to claim 8, characterized in that: The following formula is used to calculate the bending moment of the lower guide rod at the current moment: , where i = 1, 2, 3, ..., I, where , It is used to indicate the bending moment value of the lower guide rod in the i-th, i-opp bending direction at time t, N is used to indicate the total number of load chips, I is used to indicate the number of pairs of two load chips facing each other on the same cross section of the lower guide rod, and K M,i It is used to represent the bending moment coefficient of the i-th load sensor of the lower guide rod, λi(t) is used to represent the wavelength value of the i-th load chip at time t, λ0,i is used to represent the wavelength value of the i-th load chip when there is no load, and k T,i Used to represent the temperature drift coefficient of the i-th load chip, K M-opp,i-opp It is used to express the bending moment coefficient of the load chip that the i-th load chip of the lower guide rod is facing. λopp,i-opp(t) is used to express the wavelength value of the i-oppth load chip that the i-th load chip is facing at time t. λ0-opp,i-opp is used to express the wavelength value of the i-oppth load chip that the i-th load chip is facing when there is no load. T-opp,i-opp It is used to represent the temperature drift coefficient of the i-opp load chip directly opposite to the i-th load chip, T(t) is used to represent the temperature value at time t, and T0 is used to represent the temperature value at the initial time.

12. The method for measuring the state of the pantograph lower guide rod according to claim 8, characterized in that: Also includes: After determining that the spherical hinge shafts at both ends of the lower guide rod are in a stuck state, the bending direction of the lower guide rod is determined according to the positive or negative value of the bending moment at the current moment.

13. The method for measuring the state of the pantograph lower guide rod according to claim 12, characterized in that: Determining the bending direction of the lower guide rod according to the positive or negative value of the bending moment at the current moment includes: When the bending moment at the current moment is positive, determining that the middle portion of the lower guide rod protrudes into the four-bar linkage frame; When the bending moment at the current moment is negative, it is determined that the middle portion of the lower guide rod protrudes out of the four-bar linkage frame.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for measuring the state of the pantograph lower guide rod according to any one of claims 8 to 13 are executed.

15. A pantograph lower guide rod state measurement system, characterized in that: include: The pantograph lower guide rod load sensor according to any one of claims 1 to 7, configured to receive an optical signal; The processor is coupled to the load sensor and is used to process the signal collected by the load sensor.

16. A pantograph, characterized in that: The pantograph comprises the pantograph lower guide rod load sensor according to any one of claims 1 to 7 and a four-bar linkage structure; The four-bar linkage structure includes a lower guide rod, one end of which is provided with a stud hole, the other end of which is provided with a spherical hinge, the stud of the sensor body is screwed to the bolt hole of the lower guide rod, and the stud hole of the sensor body is screwed to the spherical hinge of the lower guide rod.

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