Object distance measuring device and measuring method

Abstract

The present invention relates to an object distance measurement device, comprising: a distance measurement sensor, an oscillation circuit connected in series with the distance measurement sensor, and a distance calculation module, wherein the distance measurement sensor is used to convert the distance between two objects into a capacitance signal; the oscillation circuit is used to generate an oscillation frequency signal under the excitation of the capacitance signal; and the distance calculation module is used to calculate the distance between the two objects according to the oscillation frequency signal. Accordingly, the present invention also provides a measurement method based on the object distance measurement device. The object distance measurement device provided by the present invention utilizes the relative movement of a fixed-pole capacitance element and a moving-pole capacitance element to cause a capacitance change, converts the capacitance change into an oscillation frequency change through an oscillation circuit, and then calculates the distance between the measured objects according to the oscillation frequency, without the need to use a signal amplification circuit, so that the entire device has a simple and compact structure and high measurement efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile detection equipment, and in particular to an object distance measuring device. Accordingly, a measuring method based on the object distance measuring device is also provided. Background Art

[0002] In the assembly process of automobile manufacturing, the matching gap of the car door directly affects the appearance and NVH (Noise, Vibration, Harshness) performance of the car. If the manufacturing process of the car door is rough and the body precision is poor, the contact surface of the car door seal will be uneven and the rubber strip will accumulate during manual assembly, resulting in wave phenomenon. Improper installation of the sealing strip will directly affect the acoustic quality of the door opening and the NVH quality when driving at high speed. If the gap is large and uneven, an acoustic leakage hole will be formed, and the wind noise and tire noise will be obviously transmitted into the car body, affecting the comfort of the passengers. Therefore, measuring the gap between the door stop edge and the matching surface of the side panel is an important part of controlling NVH performance.

[0003] In order to check the door gap, the traditional measurement method is to use feeler gauges, plasticine, etc. to measure and monitor, but this method has low efficiency, large errors, poor consistency of repeated measurements, complex operation, and is easily affected by the level of the measurement operator. In addition, the operating posture is difficult during measurement, the ergonomics is poor, the measurement speed is slow, and it takes a long time, which is not conducive to quickly discovering problems and calculating the dimensional stability of the manufacturing process. Some companies with strong economic strength also use imported measuring tools, whose core technology is sliding rheostat, which is expensive and has a short service life and is easy to break.

[0004] In order to solve the problems of traditional measurement methods, some people have proposed using capacitive gate sensors to measure the gap. This solution has a weak output signal, high output impedance, and poor load capacity. Therefore, an amplifier circuit is required to process the signal. Since the amplifier circuit requires components such as transformers, the entire measuring device is large in size and complex in structure.

[0005] Others have proposed the use of magnetic probes for measurement. This type of measurement equipment is heavy and must be held manually, which is inconvenient to operate and cannot achieve multi-point simultaneous measurement. In addition, the output end is a mechanical pointer type, which will be affected by the operator. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an object distance measuring device which has a simple structure, is lightweight, easy to operate and has a long service life.

[0007] The technical problem to be solved by the present invention is also to provide a measurement method to improve measurement efficiency, measurement convenience and accuracy of measurement data.

[0008] In order to solve the above technical problems, the present invention provides an object distance measurement device, comprising: a distance measurement sensor, an oscillating circuit connected in series with the distance measurement sensor, and a distance calculation module, wherein:

[0009] The distance measurement sensor is used to convert the distance between two objects into a capacitance signal;

[0010] The oscillation circuit is used to generate an oscillation frequency signal under the excitation of the capacitance signal;

[0011] The distance calculation module is used to calculate the distance between two objects according to the oscillation frequency signal.

[0012] Preferably, the spacing measurement sensor comprises: a base, a sliding measuring head connected to the base, an elastic support member located between the base and the sliding measuring head, a fixed-pole capacitor element fixed on the base, and a moving-pole capacitor element fixed on the sliding measuring head;

[0013] A first gap is formed between the fixed-pole capacitive element and the sliding measuring head;

[0014] A second gap is formed between the moving pole capacitor element and the base;

[0015] The fixed-pole capacitor element and the moving-pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two.

[0016] Preferably, the base and the sliding measuring head are parallel to each other, and the elastic support member includes a telescopic support column and a spring sleeved on the telescopic support column.

[0017] Preferably, the elastic support members are evenly distributed around the fixed-pole capacitor element in a ring shape.

[0018] Preferably, the heights of the moving pole capacitor element and the fixed pole capacitor element are both smaller than the length of the elastic support member in an uncompressed state;

[0019] The fixed-pole capacitor element is provided on the outer periphery of the moving-pole capacitor element, and a capacitor is formed between an inner surface of the fixed-pole capacitor element and an outer surface of the moving-pole capacitor element.

[0020] Preferably, a first insulating ring is provided at the end of the fixed-pole capacitor element, and a second insulating ring is provided at the end of the moving-pole capacitor element.

[0021] A method for measuring distance between objects comprises the following steps:

[0022] Place the distance measurement sensor in the gap between two objects and obtain the capacitance signal C of the distance measurement sensor at this time. x ;

[0023] The capacitance signal C x as an excitation signal for the oscillation circuit, and obtains the capacitance signal C of the oscillation circuit x The oscillation frequency signal f1 generated under the excitation;

[0024] The distance d0 between two objects is calculated based on the oscillation frequency signal f1.

[0025] Preferably, the spacing measurement sensor comprises: a base, a sliding measuring head connected to the base, an elastic support member located between the base and the sliding measuring head, a fixed-pole capacitor element fixed on the base, and a moving-pole capacitor element fixed on the sliding measuring head, wherein the fixed-pole capacitor element and the moving-pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two.

[0026] Place the distance measurement sensor in the gap between two objects and obtain the capacitance signal C of the distance measurement sensor at this time. x Specifically:

[0027] The capacitance signal Cx is obtained according to the following formula:

[0028]

[0029] Where ε is the dielectric constant of the medium, dx is the length of the overlapping area of ​​the electrode cylinder, D1 is the inner diameter of the fixed pole cylinder, and D2 is the outer diameter of the moving pole cylinder;

[0030] The oscillation circuit is used to obtain the capacitance signal C x The oscillation frequency signal f1 generated under the excitation is specifically:

[0031] The oscillation frequency f1 is obtained according to the following formula:

[0032]

[0033] Among them, C0 is the sum of coupling and parasitic capacitance, and L is the inductance of the oscillation circuit;

[0034] The calculation of the distance d0 between the two objects according to the oscillation frequency signal f1 is specifically as follows:

[0035] The distance d0 between the two objects is obtained according to the following formula:

[0036]

[0037] Among them, d1 is the length of the fixed pole cylinder, and d2 is the length of the moving pole cylinder.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The object distance measuring device provided by the present invention utilizes the relative movement of a fixed-pole capacitor element and a moving-pole capacitor element to cause a capacitance change, converts the capacitance change into an oscillation frequency change through an oscillation circuit, and then calculates the distance between the measured objects based on the oscillation frequency. There is no need to use a signal amplification circuit, so that the entire device has a simple and compact structure and high measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the object distance measuring device of the present invention;

[0041] Figure 2 It is a schematic diagram of the cross-sectional structure of the spacing measurement sensor of the present invention;

[0042] Figure 3 A schematic diagram of the cross-sectional structure of the spacing measurement sensor of the present invention from another viewing angle;

[0043] Figure 4 is a flow chart of the measurement method of the present invention;

[0044] Figure 5 It is a schematic diagram of the length relationship structure of various components of the spacing measurement sensor of the present invention. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0046] like Figure 1 As shown, an object distance measurement device includes: a distance measurement sensor 10, an oscillating circuit 20 connected in series with the distance measurement sensor 10, and a distance calculation module 30, wherein:

[0047] The distance measurement sensor 10 is used to convert the distance between two objects into a capacitance signal;

[0048] The oscillation circuit 20 is used to generate an oscillation frequency signal under the excitation of the capacitance signal;

[0049] The distance calculation module 30 is used to calculate the distance between two objects according to the oscillation frequency signal.

[0050] like Figure 2-3 As shown, the distance measurement sensor 10 is used to convert the distance between two objects into a capacitance signal, and comprises a base 1, a sliding measuring head 2 connected to the base 1, an elastic support member 3 located between the base 1 and the sliding measuring head 2, a fixed-pole capacitance element 4 fixed on the base 1, and a moving-pole capacitance element 5 fixed on the sliding measuring head 2;

[0051] A first gap is formed between the fixed-pole capacitive element 4 and the sliding measuring head 2;

[0052] A second gap is formed between the moving pole capacitor element 5 and the base 1;

[0053] The fixed-pole capacitor element and the moving-pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two.

[0054] The base 1 is used to fix the spacing measurement sensor 10, which is installed in the gap between objects for measurement. In order to facilitate the fixation of the base 1, a magnetic adsorption block 11 is provided inside the base 1 to adsorb the base on the object for measurement. The disassembly and assembly is convenient and quick, and multiple spacing measurement sensors 10 can be installed at the same time to improve the measurement efficiency.

[0055] The sliding measuring head 2 and the base 1 are arranged parallel to each other and are connected to the base 1 via an elastic support member 3. Therefore, under the action of external force, a relative displacement can be generated between the sliding measuring head 2 and the base 1, thereby achieving the purpose of measurement.

[0056] One end of the elastic support member 3 is connected to the base 1, and the other end is connected to the sliding measuring head 2. Specifically, the number of the elastic support members 3 is at least three, and they are evenly distributed around the fixed-pole capacitor element 4. In this embodiment, the elastic support members 3 are evenly distributed around the fixed-pole capacitor element 4 in a ring shape, so that the fixed-pole capacitor element 4 and the moving-pole capacitor element 5 move concentrically, ensuring the accuracy of the measurement result.

[0057] The elastic support member 3 includes a retractable support column 31 and a spring 32 sleeved on the retractable support column 31. The retractable support column 31 is a structure such as a cylinder, which is convenient for realizing the retraction and expansion of the elastic support member 3 through external force.

[0058] The fixed-pole capacitor element 4 is made of metal material and is fixed on the base 1. It has a cylindrical shell structure. In order to facilitate measurement, the height of the fixed-pole capacitor element 4 is smaller than the length of the elastic support member 3 in an uncompressed state, that is, a first gap is formed between the fixed-pole capacitor element 4 and the sliding measuring head 2.

[0059] The moving pole capacitor element 5 is made of metal material and fixed on the sliding measuring head 2. It has a cylindrical shell structure, and the moving pole capacitor element and the fixed pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two. In order to facilitate measurement, the height of the moving pole capacitor element 5 is less than the length of the elastic support member 3 in the uncompressed state, that is, a second gap is formed between the moving pole capacitor element 5 and the base 1, and the fixed pole capacitor element 4 is arranged on the periphery of the moving pole capacitor element 5, that is, a capacitor is formed between the inner surface of the fixed pole capacitor element 4 and the outer surface of the moving pole capacitor element 5. When the fixed pole capacitor element 4 and the moving pole capacitor element 5 have a relative displacement, the area of ​​the overlapping part between the fixed pole capacitor element 4 and the moving pole capacitor element 5 changes, thereby causing the capacitance to change.

[0060] It should be noted that, due to the edge effect of the capacitive electric field, that is, the charge distribution is uneven, there are sharp tips at the ends of the fixed-pole capacitor element 4 and / or the moving-pole capacitor element 5, which leads to the formation of an electric field deformity near the power supply, making the spacing measurement device using the sensor unstable and increasing the nonlinear error. In order to solve this problem, the end of the fixed-pole capacitor element 4 is also provided with a first guard ring 6 and a first insulating ring 7, and the first insulating ring 7 is located between the first guard ring 5 and the fixed-pole capacitor element 4. The end of the moving-pole capacitor element 5 is also provided with a second guard ring 8 and a second insulating ring 9, and the second insulating ring 9 is located between the second guard ring 8 and the moving-pole capacitor element 5, so as to evenly distribute the charge on the surface of the fixed-pole capacitor element 4 and the moving-pole capacitor element 5, eliminate the electric field deformity, and improve the measurement accuracy.

[0061] The object distance measuring sensor provided by the present invention has a coaxial cylindrical shell structure in which the fixed-pole capacitor element and the moving-pole capacitor element adopt a cylindrical capacitor structure, and when in use, accurate positioning can be achieved according to the center point of the cylindrical capacitor, and the object gap at the target position point can be measured, with high measurement efficiency.

[0062] The oscillation circuit is used to generate an oscillation frequency signal under the excitation of the capacitance signal, so as to ensure that the distance calculation module can calculate the distance between two objects according to the oscillation frequency signal, thereby realizing the distance measurement between the objects.

[0063] The spacing calculation module is an existing unit capable of realizing a calculation function, such as a computer, a single chip microcomputer, etc. The spacing calculation module is selected according to actual needs.

[0064] The present invention causes capacitance change and generates capacitance signal through the area change between the fixed-pole capacitance element 4 and the moving-pole capacitance element 5 in the spacing measurement sensor. The capacitance signal generates an oscillation frequency signal in the oscillation circuit. The spacing calculation module calculates the distance between the two objects according to the oscillation frequency signal. During measurement, multiple spacing measurement sensors 10 can be installed at the same time, with high measurement efficiency, convenience and speed, and reduced labor intensity of operators.

[0065] Correspondingly, such as Figure 4 As shown, the present invention also provides a method for measuring a gap based on the above-mentioned object distance measuring device, comprising the following steps:

[0066] Place the distance measurement sensor in the gap between two objects and obtain the capacitance signal C of the distance measurement sensor at this time. x ;

[0067] The capacitance signal C x as an excitation signal for the oscillation circuit, and obtains the capacitance signal C of the oscillation circuit x The oscillation frequency signal f1 generated under the excitation;

[0068] The distance d0 between two objects is calculated based on the oscillation frequency signal f1.

[0069] The distance d0 between two objects is calculated by the distance calculation module

[0070] Specifically, the calculation process of the spacing calculation module is:

[0071] like Figure 5 As shown, the specific calculation principle of the spacing calculation module is:

[0072] Place the distance measurement sensor in the gap between two objects and obtain the capacitance signal C of the distance measurement sensor at this time. x Specifically:

[0073] The capacitance signal Cx is obtained according to the following formula:

[0074]

[0075] Where ε is the dielectric constant of the medium, dx is the length of the overlapping area of ​​the electrode cylinder, D1 is the inner diameter of the fixed pole cylinder, and D2 is the outer diameter of the moving pole cylinder;

[0076] The oscillation circuit is used to obtain the capacitance signal C x The oscillation frequency signal f1 generated under the excitation is specifically:

[0077] The oscillation frequency f1 is obtained according to the following formula:

[0078]

[0079] Among them, C0 is the sum of coupling and parasitic capacitance, and L is the inductance of the oscillation circuit;

[0080] The calculation of the distance d0 between the two objects according to the oscillation frequency signal f1 is specifically as follows:

[0081] The distance d0 between the two objects is obtained according to the following formula:

[0082]

[0083] Among them, d1 is the length of the fixed pole cylinder, and d2 is the length of the moving pole cylinder.

[0084] The measuring method based on the spacing measuring device provided by the present invention can directly calculate the gap distance between the two objects through the spacing calculation module after directly placing the spacing measurement sensor 10 on the object, and can perform multiple measurements at the same time. The measurement is convenient and fast, with high efficiency and accurate measurement data. Moreover, multiple spacing measurement sensors can be installed at the same time for measurement, with high measurement efficiency.

[0085] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for measuring distance between objects, characterized in that: The following steps are involved: Place the distance measurement sensor in the gap between two objects and obtain the capacitance signal C of the distance measurement sensor at this time. x ; The capacitance signal C x as an excitation signal for the oscillation circuit, and obtains the capacitance signal C of the oscillation circuit x The oscillation frequency signal f1 generated under the excitation; Calculate the distance d0 between two objects according to the oscillation frequency signal f1; The spacing measurement sensor comprises: a base, a sliding measuring head connected to the base, an elastic support member located between the base and the sliding measuring head, a fixed-pole capacitor element fixed on the base, and a moving-pole capacitor element fixed on the sliding measuring head; A first gap is formed between the fixed-pole capacitive element and the sliding measuring head; A second gap is formed between the moving pole capacitor element and the base; The fixed-pole capacitor element and the moving-pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two; The distance d0 between the two objects is obtained according to the following formula: Among them, d1 is the length of the fixed-pole capacitor element, d2 is the length of the moving-pole capacitor element, D1 is the inner diameter of the fixed-pole capacitor element, D2 is the outer diameter of the moving-pole capacitor element, ε is the dielectric constant of the medium, L is the inductance of the oscillation circuit, and f1 is the oscillation frequency signal.

2. The object distance measurement method according to claim 1, characterized in that: The capacitance signal is obtained according to the following formula : Among them, ε is the dielectric constant of the medium, dx is the length of the overlapping area between the fixed-pole capacitor element and the moving-pole capacitor element, D1 is the inner diameter of the fixed-pole capacitor element, and D2 is the outer diameter of the moving-pole capacitor element.

3. The object distance measurement method according to claim 1, characterized in that: The oscillation frequency f1 is obtained according to the following formula: Among them, C0 is the sum of coupling and parasitic capacitance, L is the inductance of the oscillation circuit, is a capacitance signal.

4. An object distance measuring device based on the object distance measuring method according to any one of claims 1 to 3, characterized in that: include: A distance measurement sensor, an oscillating circuit connected in series with the distance measurement sensor, and a distance calculation module, wherein: The distance measurement sensor is used to convert the distance between two objects into a capacitance signal; The oscillation circuit is used to generate an oscillation frequency signal under the excitation of the capacitance signal; The distance calculation module is used to calculate the distance between two objects according to the oscillation frequency signal; The spacing measurement sensor comprises: a base, a sliding measuring head connected to the base, an elastic support member located between the base and the sliding measuring head, a fixed-pole capacitor element fixed on the base, and a moving-pole capacitor element fixed on the sliding measuring head; A first gap is formed between the fixed-pole capacitive element and the sliding measuring head; A second gap is formed between the moving pole capacitor element and the base; The fixed-pole capacitor element and the moving-pole capacitor element are coaxial cylindrical shell structures, and a capacitor is formed between the two.

5. The object distance measuring device according to claim 4, characterized in that: The base and the sliding measuring head are parallel to each other, and the elastic support member comprises a telescopic support column and a spring sleeved on the telescopic support column.

6. The object distance measuring device according to claim 5, characterized in that: The elastic supporting member is evenly distributed around the fixed-pole capacitor element in a ring shape.

7. The object distance measuring device according to claim 4, characterized in that: The heights of the moving pole capacitor element and the fixed pole capacitor element are both smaller than the length of the elastic support member in an uncompressed state; The fixed-pole capacitor element is provided on the outer periphery of the moving-pole capacitor element, and a capacitor is formed between an inner surface of the fixed-pole capacitor element and an outer surface of the moving-pole capacitor element.

8. The object distance measuring device according to claim 4, characterized in that: A first insulating ring is disposed at the end of the fixed-pole capacitor element, and a second insulating ring is disposed at the end of the moving-pole capacitor element.

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