A high-precision ultrasonic ranging method and device independent of temperature compensation mechanism

Abstract

A high-precision ultrasonic ranging method independent of temperature compensation mechanism, where the ultrasonic probe is arranged on a control handle with at least two segments that can automatically extend and retract. Ultrasonic ranging is performed at the positions of different segments on the control handle, the time intervals of signal transmission and reception at each position are measured, and the distance is calculated using the least squares method. And a high-precision ultrasonic ranging device independent of temperature compensation mechanism is provided, which includes an ultrasonic probe, a control handle and a control unit. The control handle is a control handle with at least two segments that can automatically extend and retract. The ultrasonic probe is installed at the end of the control end. The signal transmission and reception terminals of the ultrasonic probe are connected to the control unit. The control unit includes an action control module for controlling the extension and retraction of the control handle according to different segments, and a distance calculation module for calculating the distance using the least squares method according to the transmission and reception time intervals of different segments. The present invention is independent of temperature compensation and has relatively high precision.

Description

Technical Field

[0001] The present invention relates to an ultrasonic ranging method and device. Background Art

[0002] By utilizing the characteristic of good directivity of ultrasonic propagation, a ranging and positioning device can be designed. Its main working principle is as Figure 1 . Such as Figure 1 The direction of the ultrasonic probe ensures that the emission line perpendicularly reaches the surface of the ranging object, and the reflected line also perpendicularly returns along the original path. Thus, the time interval between emission and reception is the ultrasonic propagation time for the double journey of the measured distance. Using the formula

[0003]

[0004] s can be obtained.

[0005] In the above formula, v 0 is the air sound speed of 340 meters per second, and t is determined by the timer of the rangefinder. Thus, the measured distance This method has a problem that it is necessary to ensure the perpendicularity between the surface of the ranging object and the ultrasonic probe. Secondly, generally, an ultrasonic transceiver integrated probe is used, which can repeatedly switch between emission and reception. If the surface of the ranging object is not perpendicular to the probe direction, or if a separate emission and reception probe is used, then it involves multiple probes or a probe array and triangular distance calculation. These situations are as Figure 2 and Figure 3 shown.

[0006] Regardless of which of the above situations, there is a unique problem in ultrasonic ranging, that is, the sound speed changes with the medium temperature. For example, in air, it is not always 340 meters per second. Therefore, there is a so-called temperature compensation algorithm for high-precision ultrasonic ranging, that is, calculated by the formulas v = 331.4 + 0.61T and s = vt / 2, where v is the sound speed varying with the air temperature T, and t is the emission and reception time interval measured by the timer. Naturally, such a system must carry an environmental temperature measurement module, generally a temperature measurement circuit. Summary of the Invention

[0007] In order to overcome the deficiencies of the existing ultrasonic ranging technology, which depends on temperature compensation and has low precision, the present invention provides a high-precision ultrasonic ranging method and device that does not rely on a temperature compensation mechanism.

[0008] The technical solution adopted by the present invention to solve its technical problems is:

[0009] A high-precision ultrasonic ranging method that does not rely on a temperature compensation mechanism, where the ultrasonic probe is arranged on a control handle with at least two telescopic segments. Ultrasonic ranging is respectively performed at the positions of different segments on the control handle, the emission and reception time intervals at each position are measured, and the least squares method is used to calculate the distance.

[0010] Furthermore, the control handle is provided with 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments. Of course, it can also be other quantities, such as 2 segments, 4 segments, or 5 segments, etc.

[0011] Furthermore, it is set that the length of each segment is equal, all being h. Assume that the ranging object has no displacement in the ultrasonic propagation line, but can have displacement in the direction perpendicular to the propagation line, and the surface of the ranging object remains flat. Assume that the measured time intervals of transmission and reception at each position of the probe are t 1 , t 2 , t 3 , t 4 , and the equations are listed as follows

[0012]

[0013]

[0014]

[0015]

[0016] where s and v are unknown, and t 1 , t 2 , t 3 , t 4 and h are known;

[0017] Calculated using the least squares method:

[0018]

[0019] Calculate the above matrix multiplication formula to obtain the distance s.

[0020] Preferably, the process of the least squares method is as follows:

[0021] Arrange Equation (1) into matrix form as follows:

[0022]

[0023] Since t 1 , t 2 , t 3 , t 4 are not equal to each other, the rank of the matrix is 2, so it is column full rank. Multiply both sides of the above matrix equation by the transpose matrix Then there is

[0024]

[0025] Obtain

[0026]

[0027] Finally, the formula (2) is obtained.

[0028] A high-precision ultrasonic ranging device that does not rely on a temperature compensation mechanism, including an ultrasonic probe, a control handle, and a control unit. The control handle is a control handle with at least two segments that can automatically expand and contract. The ultrasonic probe is installed at the end of the control end. The signal transmitting and receiving ends of the ultrasonic probe are connected to the control unit. The control unit includes an action control module for controlling the expansion and contraction of the control handle in different segments, and a distance calculation module for calculating the distance using the least squares method according to the transmission and reception time intervals of different segments.

[0029] Furthermore, the control handle has an embedded motor for controlling the expansion and contraction.

[0030] Still further, the control handle is provided with 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments.

[0031] Even further, the device includes a display module, and the control unit is connected to the display module.

[0032] The beneficial effects of the present invention are mainly manifested in: not relying on temperature compensation and having relatively high precision. Description of the Drawings

[0033] Figure 1 It is the schematic diagram of ultrasonic ranging principle.

[0034] Figure 2 It is the schematic diagram of the separation of the transmitting and receiving probes.

[0035] Figure 3 It is the schematic diagram of multiple probes.

[0036] Figure 4 It is the schematic diagram of the ultrasonic ranging principle that does not rely on the temperature compensation mechanism. 1 represents the probe handle, 2 represents the probe, 3 represents the surface of the ranging target object. The solid line represents ultrasonic emission, and the dashed line represents ultrasonic reception.

[0037] Figure 5 It is the schematic diagram of the principle of the high-precision ultrasonic ranging device that does not rely on the temperature compensation mechanism. Detailed Embodiments

[0038] The present invention will be further described below with reference to the accompanying drawings.

[0039] Refer to Figure 4, A high-precision ultrasonic ranging method that does not rely on a temperature compensation mechanism. The ultrasonic probe is arranged on a control handle with at least two telescopic segments. Ultrasonic ranging is performed at different positions on the control handle to measure the time intervals between transmission and reception at each position, and the least squares method is used to calculate the distance.

[0040] Furthermore, the control handle has 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments. Of course, it can also be other numbers, such as 2 segments, 4 segments, or 5 segments, etc.

[0041] Furthermore, it is set that the length of each segment is equal, all being h. Assuming that the ranging object has no displacement in the ultrasonic propagation line, but can have displacement in the direction perpendicular to the propagation line, and the surface of the ranging object remains flat. Assuming that the time intervals between transmission and reception measured at each position of the probe are t 1 , t 2 , t 3 , t 4 , the following equations are listed

[0042]

[0043]

[0044]

[0045]

[0046] Among them, s and v are unknown, and t 1 , t 2 , t 3 , t 4 and h are known;

[0047] Using the least squares method, it is calculated that:

[0048]

[0049] Calculating the above matrix multiplication formula to obtain the distance s.

[0050] Preferably, the process of the least squares method is as follows:

[0051] Rearranging Equation (1) into matrix form as follows:

[0052]

[0053] Since t 1 , t 2 , t 3 , t 4 are not equal to each other, the matrix has a rank of 2 and is thus column full rank. Multiply both sides of the above matrix equation by the transpose matrix Then we have

[0054]

[0055] We obtain

[0056]

[0057] Finally, we obtain Equation (2).

[0058] Referring to Figure 5 , a high-precision ultrasonic ranging device that does not rely on a temperature compensation mechanism, includes an ultrasonic probe, a control handle, and a control unit. The control handle is an at least two-segment control handle that can automatically expand and contract. The ultrasonic probe is installed at the end of the control end. The signal transmitting and receiving ends of the ultrasonic probe are connected to the control unit. The control unit includes an action control module for controlling the expansion and contraction of the control handle in different segments, and a distance calculation module for calculating the distance using the least squares method according to the transmission and reception time intervals of different segments.

[0059] Furthermore, the control handle has an embedded motor for controlling the expansion and contraction.

[0060] Still further, the control handle is provided with 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments.

[0061] Even further, the device includes a display module, and the control unit is connected to the display module. The control handle is connected to the power supply.

[0062] As Figure 3 , a transceiver integrated probe is arranged on a multi-segment control handle that can automatically expand and contract. The multi-segment means that it can perform operations such as extending and retracting in whole segments according to multiple segments, and this operation is automatically controlled by program instructions. For convenience or good appearance, the lengths of these segments can be designed to be the same, such as Figure 3 A total of 3 segments are set. Our method ensures that at least 1 segment is required to complete the ranging, that is, two states: in-situ and retracted by one segment. The upper limit of the segments is generally set to 5 segments. Too many segments will increase the calculation amount and is not conducive to the low-power requirements of embedded devices. Figure 3 Setting 3 segments makes the probe have four position states, namely in-situ, retracted by one segment, retracted by two segments, and retracted by three segments.

[0063] Because it was previously assumed that the length of each segment is equal (methodologically speaking, this method can be implemented even if the actual length is unequal), let it be set to h. The value of h is naturally known in the calculation. In order to control the length of the device, this value can be designed to be 4 cm. Secondly, let us assume that the distance measuring object does not have any displacement on the ultrasonic propagation line, but can have displacement in the vertical direction of the propagation line, and the surface of the distance measuring object remains flat. Assume that the time interval between sending and receiving measured by the device at each position of the probe is t 1 ,t 2 ,t 3 ,t 4 , list equation (1), use the least squares method to calculate the matrix multiplication formula (4), calculate (4), we can get the distance s, and incidentally we can also measure the speed of sound v.

[0064] The high-precision ultrasonic distance measuring device of this embodiment that does not rely on the temperature compensation mechanism is to place the integrated transceiver probe on a multi-segment automatic control handle. Figure 4 As shown, it contains an ultrasound probe, a control handle (including a drive motor), a control unit, a display module and a power supply.

[0065] The working process of the high-precision ultrasonic distance measuring device of this embodiment that does not rely on the temperature compensation mechanism is as follows:

[0066] Step 1. After the device is powered on, the probe performs a transmission and reception in the original position, and the timing is performed;

[0067] Step 2. After the probe is retracted one section, it sends and receives once and counts the time;

[0068] Step 3. Repeat step 2 until each layer of segments is indented;

[0069] Step 4. Extend one section, send and receive once, and time it;

[0070] Step 5. Repeat step 4 until each layer of segments is extended;

[0071] Step 6. Return to step 2.

[0072] The above is just the automatic operation process of the probe. Regarding the output of distance calculation, the process is as follows:

[0073] 1) If it is the first time to power on, then wait until all segments are indented, that is, perform the first calculation and output the distance after step 3 above. The calculation method is the least squares method;

[0074] 2) If it is during the operation after the first calculation, and the probe position in each of the above steps is different from that in the previous step, take the current position probe's timing together with the three immediately preceding probe timings, combine them into the latest consecutive four timings for least squares calculation, and output the distance.

[0075] It can be seen that the distance output can be achieved in any probe state. From this perspective, in fact, the calculation output has no delay, and the output frequency only has a short pause during the segment expansion and contraction. Assuming that it takes 100 milliseconds to complete the expansion and contraction of one segment, then an output is performed every interval of "100 milliseconds +", where the "+" part is the actual measurement duration, which is related to the distance of the ranging object.

[0076] This embodiment only describes this method for an ultrasonic transceiver integrated probe, and it is a single probe. Obviously, this method can be easily applied to a system with multiple probes (probe array) or transceiving separated probes.

Claims

1. A high-precision ultrasonic ranging method independent of temperature compensation mechanism, characterized in that, the ultrasonic probe is arranged on a control handle with at least two segments that can automatically expand and contract. Ultrasonic ranging is performed at different positions of different segments on the control handle, the time intervals of signal transmission and reception at each position are measured, and the distance is calculated using the least squares method; the control handle has 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments; Set the length of each segment to be equal, all being h. Assume that the ranging object has no displacement along the ultrasonic propagation line, but can have displacement in the direction perpendicular to the propagation line, and the surface of the ranging object remains flat. Assume that the measured time intervals between transmission and reception at various positions of the probe are t 1 , t 2 , t 3 , t 4 , and list the equations as follows where s, v are unknown, and t 1 , t 2 , t 3 , t 4 and h are known; using the least squares method to calculate: calculate the above matrix multiplication formula to obtain the distance s; the process of the least squares method is: Arrange Equation (1) into matrix form as follows: Since t 1 , t 2 , t 3 , t 4 are not equal to each other, the rank of the matrix is 2, so it is column full rank. Multiply both sides of the above matrix equation by the transpose matrix Then we have obtain finally obtain Equation (2).

2. An apparatus for implementing the high-precision ultrasonic ranging method independent of temperature compensation mechanism as claimed in claim 1, characterized in that, the apparatus includes an ultrasonic probe, a control handle and a control unit. The control handle is a control handle with at least two segments that can automatically expand and contract. The ultrasonic probe is installed at the end of the control end. The signal transmission and reception end of the ultrasonic probe is connected to the control unit. The control unit includes an action control module for controlling the expansion and contraction of the control handle according to different segments, and a distance calculation module for calculating the distance using the least squares method according to the transmission and reception time intervals of different segments.

3. The apparatus as claimed in claim 2, characterized in that, the control handle has an embedded motor for controlling the expansion and contraction.

4. The apparatus as claimed in claim 2 or 3, characterized in that, the control handle has 3 segments, and the probe has four position states: in-situ, retracted by one segment, retracted by two segments, and retracted by three segments.

5. The apparatus as claimed in claim 2 or 3, characterized in that, the apparatus includes a display module, and the control unit is connected to the display module.

Images