JPS60119485A - Microwave distance measuring equipment - Google Patents

Abstract

PURPOSE:To measure at high accuracy by shifting and setting an antenna section to a distance between an object and antenna having small noise. CONSTITUTION:A microwave circuit 2 in the antenna section 16 mixes sending waves and receiving waves and detects beat waves. The beat waves are inputted to a period counting circuit 8 through an amplifier circuit 7, and beat period is counted. The distance between the antenna and a measured face is calculated by a distance calculating circuit 9 basing on the result of counting. A drive commanding section 10 determines optimum position of the antenna from the result of calculation and feeds drive command of the antenna section 16. On receiving this drive command, a driving device 11 drives the antenna section 16. The distance signal outputted from a distance correcting circuit 13 is led to outside from an output circuit 14.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention continuously frequency-modulates microwaves and transmits them to a surface to be measured, and the beat signal period of the transmitted wave and the reflected wave from the surface to be measured is This invention relates to a device that measures the distance to a surface to be measured.

[Prior art and its problems]

In a conventional microwave distance measuring device, as shown in Fig. 1, (21) is an antenna, (22) is a waveguide, and (2) is a waveguide.
3) is a microwave circuit, (24) is a signal processing device), and the device including the antenna section consisting of the antenna (21) to the microwave circuit (23) has been used in a fixed manner. In this case, multiple reflection noise occurs between the antenna and the target object at the position of the target object like ■ in the figure, and conversely, in the situation like ■ there is noise from outside the target object, such as a non-target object (25). Reflection noise occurs. Measurement errors increase due to the generation of these noises. Figure 2 shows the relationship between the distance between the antenna and the object and the error.As mentioned above, the error increases at close range due to multiple reflections and at long distances due to reflected noise from outside the target. . Furthermore, if accuracy is to be maintained, the measurement range will be limited as shown in area (3) in the figure.

[Purpose of the invention]

According to the present invention, based on the measurement results of distances measured by a microwave distance measuring device, if the antenna is located in a position where there is a lot of noise (areas I and III in Figure 2), the antenna position is changed to an area with less noise (areas shown in Figure 2). The object of the present invention is to provide a microwave distance measuring device that is highly accurate and has a wide measurement range by moving and setting the antenna in the H area of 1) and re-measuring.

[Structure of the invention]

The micro distance measuring device of the present invention determines the optimum position of the antenna from the distance calculated from the beat signal period generated by mixing the reflected wave and the transmitted wave from the surface to be measured, and issues a drive command for the antenna. A drive command circuit to send out,
A drive device that moves the antenna to the optimum position in response to the drive command, a position detection circuit that detects the amount of movement of the antenna, and a distance between the antenna and the surface to be measured when the antenna is at the optimum position. and a distance correction circuit that calculates the sum or difference between the antenna movement amount and the antenna movement amount.

〔Example〕

Hereinafter, the present invention will be explained based on examples. Fig. 3 is a block diagram showing an embodiment of the present invention, in which (1) shows a modulation circuit for frequency modulating microwaves, and (2) shows a built-in microwave oscillator for mixing transmitted waves and received waves. A microwave circuit (4) is a microwave circuit (1, 1) that radiates frequency-modulated microwaves to the surface to be measured (15) via a waveguide (3). The antenna (5) is a receiving antenna that receives waves reflected from the surface to be measured (15), and (6) is the receiving antenna (5).
a waveguide that guides the received waves to the microwave circuit (2);
(7) is the signal amplification circuit after detecting the beat signal, (8
) is a period counting circuit that counts the beat period, (9) is a distance calculation circuit that calculates the distance between the antenna and the surface to be measured from the counting results, and 00) is the driving of the antenna part (16) that determines the optimum antenna position from the calculation results. Drive command circuit that issues commands (11
) is a drive device that drives the antenna section (16) in response to this command signal, (12) is a position detection circuit that detects the amount of movement of the antenna section, and (13) is a circuit that calculates the amount of movement and distance (
9) A distance correction circuit that calculates the distance from a reference point such as the most retracted position of the antenna to the surface to be measured based on the distance output from (
14) is an output circuit that receives the distance signal from the distance correction circuit (13) and outputs it to the outside; (15) is the object; (17)
is a signal processing section.

Next, the operation will be explained with reference to the operation diagram shown in FIG.

It is now assumed that the antenna position is at the most retracted position, the distance between the antenna and the surface to be measured is long, the antenna is in the area marked ■ in FIG. 2, and the object is stationary.

Measurements are taken in area A in the figure and compared with the previously stored boundary values between the area 2 and the area 2 in FIG. 2, and as a result, it is detected that the antenna position is too fast. In this state, measurement accuracy is poor due to noise generated outside the object. A command to move the antenna section is issued in section B in the figure, and the antenna section is moved to a position in the middle of the area marked ■ in FIG. 2 and stopped so as not to be affected by error fluctuations. With the movement, the influence from noise sources is reduced, so errors are reduced, and the distance between the surfaces to be measured can be measured with high precision.

In the distance correction circuit, the final output from the reference point can be obtained by adding the output Rx of the position detection circuit and the output RM of the distance calculation circuit. The object moves and the area ■
Even if the antenna is off, the antenna is moved to the optimal position and measurement is performed using the sequence described above.

FIG. 5 shows another embodiment of the present invention, which has a configuration (1
) to (9) are the same as in the previous embodiment.

The command circuit (00) calculates the difference between the output of the distance calculation circuit (9) and the reference level, and issues commands to move the antenna section forward or backward so that this difference becomes zero. This reference level is a level (distance) within area 3 in FIG. 2, and is previously set and stored for a certain object. The distance correction circuit (13) adds the reference level signal and the output of the position detection circuit (12), and the output circuit (14) outputs the distance from the reference point.

(Effects of the Invention) As described above, according to the present invention, highly accurate measurement is possible by moving and setting the antenna part at a distance between the object and the antenna with less noise, and it is also possible to detect the amount of movement.・By adding the values, it is possible to achieve high accuracy and significantly expand the measurement range.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an overview of the conventional device configuration, and FIG. 2 is a graph showing the relationship between the distance between the antenna and the object and the error.
FIG. 3 is a block diagram showing the configuration of the embodiment device of the present invention;
FIG. 4 is an explanatory diagram showing its operation, and FIG. 5 is a block diagram showing another embodiment of the present invention. (1) - Modulation circuit (2) Two microwave circuits (3): Waveguide (4): Transmitting antenna (5): Receiving antenna (6): Waveguide (7): Signal amplification circuit (8): Period counting circuit (9): distance l1Ill/! 4 calculation circuit 00): Drive command circuit (11): Drive device (12): Position detection circuit (13): Distance correction circuit (14): Output circuit (15): Target object (16): Antenna section (17) :Signal processing section patent applicant Yaskawa Electric Co., Ltd. Agent Kofuri
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Claims (1)

[Claims] 1. Microwaves are continuously frequency-modulated and transmitted to the surface to be measured, and the reflected wave from the surface to be measured and the transmitted wave are mixed to generate a beat signal period. A device for measuring a distance to a surface to be measured, comprising: a drive command circuit that determines the optimum position of the antenna from the distance calculated from the beat signal period and sends a drive command for the antenna; a driving device that moves the antenna to the optimum position; a position detection circuit that detects the amount of movement of the antenna; and a position detection circuit that detects the distance between the antenna and the surface to be measured and the amount of antenna movement when the antenna is at the optimum position. A microwave distance measuring device characterized by comprising a distance correction circuit that calculates a sum or a difference.