CN111380486A - High-resolution angular displacement measuring device and method for micro-thrust measurement - Google Patents

Abstract

The invention discloses a high-resolution angular displacement measuring device and a method for measuring micro thrust. The measuring device includes a laser displacement sensor, a bracket, an Archimedes measuring block, and a data acquisition instrument. The Archimedes measuring block rotates coaxially with the measured target, and its outer diameter increases linearly with the azimuth angle. Calculate the angular displacement of the measured target by changing the distance between the side surfaces of the Kimede measurement block; the measurement step includes (1) the laser displacement sensor emits measurement light to measure the distance between it and the side surface of the Archimedes measurement block, ( 2) The data acquisition instrument collects and records the analog signal voltage output by the laser text displacement sensor, and (3) calculates the angular displacement of the measured target through the change of the output voltage. The invention has the advantages of simple principle, fast response speed during measurement and high measurement resolution, and solves the shortcomings of the existing angular displacement measurement method, such as complex principle, high manufacturing cost, and difficulty in debugging.

Description

A high-resolution angular displacement measuring device and method for measuring tiny thrust

technical field

The invention relates to the technical field of measurement, in particular to a high-resolution angular displacement measurement device and a method for measuring tiny thrust.

Background technique

The ground thrust measurement of the micro-thrust is an indispensable key link in its development process. The precise measurement of the micro-thrust can provide necessary reference data for its design improvement, parameter selection and performance evaluation. The thrust of the micro thruster is usually mN or even μN, which is difficult to measure directly by force sensors. Most of the existing micro thrust measurement devices calculate the thrust by measuring the displacement or deformation of the bench under the action of thrust. Among them, MIT and Beihang respectively proposed a micro-thrust measurement method based on magnetic suspension bearings, which calculates the micro-thrust by measuring the angular displacement of the suspended rotor under the action of the thruster. However, the thrust-to-weight ratio of microthrusters is very small, typically below <10 ^-5 , placing high demands on the resolution of angular displacement measurements.

The invention proposes a high-resolution angular displacement measuring device and a method for measuring tiny thrust, which have the remarkable advantages of fast response speed, high measurement resolution, low manufacturing cost and the like.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a high-resolution angular displacement measuring device and a method for measuring micro-thrust in view of the above problems. The technical scheme of the present invention is as follows:

A high-resolution angular displacement measurement device for micro thrust measurement, comprising: a laser displacement sensor, the sensor can output the displacement change of the measured target as an analog signal voltage, the response time is not more than 5ms, and the measurement resolution can be up to 2 μm; bracket, which is used to fix the laser displacement sensor, and can adjust the vertical height and horizontal position of the laser sensor; data acquisition instrument, which can receive and record the analog signal output by the laser displacement sensor; A Kimed measuring block, the measuring block is coaxially and fixedly connected with the tested target and rotates synchronously with it, the outer diameter R (unit: mm) of the measuring block is linear with the increase of the azimuth angle θ (unit: °) increase, to satisfy the following mathematical relationship:

R=72+(1/5)×θ(0≤θ≤360°)

Correspondingly, the angle change Δθ (unit: °) of the Archimedes measurement block satisfies the following mathematical relationship:

Δθ=5×ΔR

Among them, ΔR (unit: mm) is the change in the outer diameter of the Archimedes measuring block. The measurement resolution of the laser displacement sensor is 0.002mm, and the corresponding angular displacement measurement resolution is 0.01°.

A high-resolution angular displacement measurement method for micro thrust measurement, comprising the following steps:

(1) The laser displacement sensor emits measuring light to measure the distance L (unit: mm) between it and the side surface of the Archimedes measuring block;

(2) The data acquisition instrument collects and records the analog signal voltage U (unit: V) output by the laser displacement sensor;

(3) Calculate the angular displacement variation Δθ (unit: °) of the Archimedes measurement block according to the variation ΔU (unit: V) of the analog signal voltage.

Further, in the step (3), the variation ΔU of the analog signal U recorded by the data acquisition instrument satisfies the following mathematical relationship:

ΔU=ΔL=ΔR

Among them, ΔL (unit: mm) is the variation of the distance between the laser displacement sensor and the Archimedes measurement block.

At any time, the angular displacement of the mechanism to be tested is:

Δθ=5×ΔU

The advantages of the present invention are:

1) The principle is simple, the angular displacement Δθ of the measured target can be calculated only by measuring a physical quantity U;

2) The response speed is fast, and the response time of the laser displacement sensor does not exceed 5ms;

3) The measurement resolution is high, the measurement resolution of the laser displacement sensor can reach 2μm, and the corresponding angular displacement measurement resolution can reach 0.01°;

4) Non-contact measurement will not cause any interference to the motion state of the measured target.

Description of drawings

1 is a schematic diagram of a measuring device of the present invention;

Fig. 2 is the schematic diagram of Archimedes measuring block of the present invention;

Fig. 3 is the measurement principle schematic diagram of the present invention;

FIG. 4 is a flow chart of the measurement method of the present invention.

1-Laser displacement sensor; 2-Archimedes measuring block; 3-Bracket; 4-Data acquisition instrument.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

The present invention is a non-contact high-resolution angular displacement measuring device based on a laser displacement sensor. As shown in FIG. 1, the measuring device includes a laser displacement sensor 1, an Archimedes measuring block 2, a bracket 3, and a data acquisition instrument. 4;

The laser displacement sensor 1 can convert the detected distance change ΔL into an analog signal ΔU output, and for every 1mm change in the distance, the output voltage correspondingly changes by 1V, that is:

ΔU=ΔL

The measurement repeatability error of the laser displacement sensor 1 does not exceed 2μm, and the response time does not exceed 5ms;

The laser displacement sensor 1 is fixed on the bracket 3 by screws, and remains stationary during measurement;

The bracket 3 includes two vertical and horizontal linear guide rails. Before the measurement, the laser displacement sensor 1 and the Archimedes measurement block 2 are adjusted to maintain the same height, and the emitting end of the laser displacement sensor 1 is adjusted to align with the Archimedes measurement block. 2 the center of the circle;

The Archimedes measuring block 2 is processed by high-precision wire cutting, and has a threaded hole in the center, which is coaxially and fixedly connected to the measured target through screws. During measurement, it rotates synchronously with the measured target, and its outer diameter R varies with the azimuth angle. increases linearly with the increase of , satisfying the following mathematical relationship:

R=72+(1/5)×θ(0≤θ≤360°)

The data acquisition instrument 4 is connected with the computer, and can collect and record the analog signal voltage output by the laser displacement sensor 1 .

A high-resolution angular displacement measurement method for micro thrust measurement of the present invention, the measurement steps are shown in Figure 4, including:

Step 1, the laser displacement sensor 1 emits measurement light to measure the distance L between it and the side surface of the Archimedes measurement block 2;

Further, the distance variation ΔL between the laser displacement sensor 1 and the side surface of the Archimedes measurement block 2 satisfies the following mathematical relationship:

ΔL=ΔR=(1/5)×Δθ

Step 2, the data acquisition instrument 4 collects and records the analog signal voltage U output by the laser displacement sensor;

Step 3: Calculate the angular displacement variation Δθ of the Archimedes measurement block according to the variation ΔU of the analog signal voltage.

Further, the variation ΔU of the analog signal U recorded by the data acquisition instrument 4 satisfies the following mathematical relationship:

ΔU=ΔL=ΔR=(1/5)×Δθ

Therefore, at any time, the angular displacement of the measured target is Δθ=5×ΔU

The present invention proposes a high-resolution angular displacement measuring device for micro thrust measurement, and discloses a corresponding measuring method, which converts the angular displacement change into the difference between the measuring block and the laser displacement sensor through the Archimedes measuring block. The distance changes, the principle is simple, the measurement resolution is high, the response speed is fast, and it has strong practicability.

Claims (4)

1. a high-resolution angular displacement measuring device for tiny thrust measurement, characterized in that it comprises a laser displacement sensor, a bracket for installing and adjusting the height and horizontal position of the laser sensor, an Archimedes measurement block, a collection and A data collector that records the output signal of the laser sensor. The laser displacement sensor is fixed on the bracket by screws, and the bracket is adjusted to maintain the same height as the Archimedes measuring block, and its laser emitting end is aligned with the center of the Archimedes measuring block; the Archimedes measuring block is cut by high-precision wire It is machined and has a threaded hole in the center, which is coaxially and fixedly connected to the measured target through screws, and rotates synchronously with the measured target during measurement; the data acquisition instrument is connected to the computer, which can collect and record the analog signal voltage output by the laser displacement sensor. 2. A high-resolution angular displacement measuring device for measuring tiny thrust as claimed in claim 1, wherein the outer diameter of the Archimedes measuring block increases linearly with the azimuth angle, and its outer diameter R and The angle θ satisfies the following mathematical relationship: R=72+(1/5)×θ (0≤θ≤360°) 3. a high-resolution angular displacement measuring method for tiny thrust measurement, is characterized in that, comprises the steps: (1) The laser displacement sensor emits measuring light to measure the distance between it and the side surface of the Archimedes measuring block; (2) The data acquisition instrument collects and records the analog signal voltage output by the laser displacement sensor; (3) Calculate the angular displacement variation of the Archimedes measuring block according to the variation of the analog signal voltage. 4. a kind of high-resolution angular displacement measuring device method for tiny thrust measurement as claimed in claim 3, is characterized in that, utilizes the Archimedes measuring block of special design, the angular displacement change of the measured target is converted into For the distance change between the laser displacement sensor and the side surface of the Archimedes measurement block, the measurement resolution can reach 0.01°.

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