JPH0612319B2 - Drive control method of hammer for impact inspection - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for driving a hammer for hitting inspection, in which an impact force is applied to a measured object to inspect the condition of the measured object.

[Conventional technology]

It is known that when the surface of an object is struck, the timbre changes due to changes in the internal structure of the object, such as the thickness of the object changing and the columns inside. This is because the hit object vibrates under the impact force to generate sound, but when the internal structure of the hit object changes, the frequency and waveform of the sound change according to changes in rigidity and density. . This phenomenon also occurs when peeling or cracks exist inside the object. For this reason, it is often practiced to utilize this phenomenon to apply a striking force to the object to be measured and inspect the internal defect of the object to be measured from the sound generated by the object to be measured.

In such a batting test, an expert hits an object to be measured with a hammer for hammering, which is generally called a test hammer or a coin tap hammer, and a person's ear detects a change in tone color. It is widely used for peeling inspection of tiles, peeling inspection of tiles, crack occurrence inspection in material, and inspection of joist and core material in wallboard.

However, in the conventional hitting inspection method described above, only a person skilled in the art can determine the presence / absence of a defect, and in the case of inspecting a large surface that easily causes individual differences, the nerves of a person who takes an inspection become tired. If the object to be measured is in a dangerous place, it may be impossible to judge if the object to be measured is in a dangerous place because it cannot be distinguished, or if the normal part and the abnormal part are separated from each other. There is a drawback that it is difficult to discriminate in a place where there is noise that cannot be performed and automation cannot be performed.

For this reason, it is conceivable to mechanize manual inspections, driving the hammer mechanically, converting the sound produced by the DUT into an electrical signal with a microphone for frequency analysis, and determining the timbre with a voice recognition method. However, there is a hitting inspection device that inspects the object to be measured for abnormality. However, since the conventional impact inspection device discriminates between the normal part and the abnormal part by the tone color by the method of frequency analysis or voice recognition, the discrimination method is complicated, and the criterion of the discrimination method is changed every time the measured object changes. Need to change.

Therefore, the inventors have studied a hitting inspection method capable of easily detecting an abnormal part occurring in the object to be measured, and after various studies, as a result, disclosed in Japanese Patent Application Laid-Open No. 61-2000
As disclosed in No. 55, it has been clarified that it is possible to easily determine whether or not there is an abnormal portion on the measured object by examining the length of the contact time between the hammer and the measured object.

Further, according to the subsequent research conducted by the inventors, by analyzing a waveform signal corresponding to the reaction force received by the hammer from the object to be measured when the hammer is hit on the measurement target, that is, based on the reaction force received by the hammer. By examining the symmetry before and after the peak of the waveform, it was clarified that the presence or absence of abnormality of the measured object can be determined.

[Problems to be solved by the invention]

As described above, in order to check the length of the contact time between the hammer and the measured object and the waveform based on the reaction force acting on the hammer, only the inertial force of the hammer when hitting the measured object with the hammer is used. It is necessary to apply a striking force to the object to be measured so that the object to be measured can naturally separate from the object to be measured. However, in the conventional manual impact and conventional impact inspection devices,
Since the hammer continues to be urged toward the DUT even after the hammer starts contacting the DUT, analyze the waveform signal of the contact time between the hammer and the DUT and the reaction force received by the hammer. There was a drawback that I could not.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a drive control method for a hammer for striking inspection, which can give a striking force to an object to be measured only by the inertial force of the hammer. And

[Means for solving problems]

In order to achieve the above object, the drive control method of a hammer for hammering inspection according to the present invention is a drive control method of a hammer for hammering hammer driving that gives a hammering force to an object to be measured, and is separated from the object to be measured. The hammer is driven toward the object to be measured, and when the hammer starts contact with the object to be measured, the driving of the hammer is stopped.

Further, the above hammer drive control method can detect that the hammer is separated from the object to be measured, and can cause the hammer to return.

[Action]

According to the present invention configured as described above, when the hammer starts contacting the object to be measured, the driving of the hammer is stopped, so that the hammer continues to be driven against the reaction force received from the object to be measured even after contacting the object to be measured. In other words, the impact force is applied to the measured object only by the inertial force. Therefore, the contact time between the hammer and the object to be measured depends on the repulsive force corresponding to the inner rod structure of the object to be measured, and the accuracy that the hammer receives when the hammer hits the object to be measured with inertial force. It is possible to obtain a waveform signal based on various reaction forces. As a result, it is possible to easily detect the presence or absence of the internal defect of the measured object by examining the contact time between the hammer and the measured object and the waveform signal of the reaction force.

Also, when the hammer starts contacting the object to be measured, the hammer drive is stopped, and when the hammer separates from the object to be measured and the hammer is returned to its original state, re-contact due to the weight of the hammer can be prevented. The contact time with the object to be measured can more accurately correspond to the internal structure of the object to be measured.

〔Example〕

A preferred embodiment of a driving control method for a hammer for hammering according to the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a block diagram of a percussion inspection device to which the drive control method for the percussion inspection hammer according to the embodiment of the present invention is applied.

In FIG. 3, the hammer 22 has a substantially conical warhead-shaped hammer head 42, an impact sensor 44, and a weight 46, which are integrated by bonding or the like. Further, in the hammer 22, the operating rod 47 is connected to the weight 46, and the upper part of the operating rod 47 is the plunger 4.
5 is inserted in the hammer driving section 24.
The hammer driving unit 24 is connected to the hammer 2 via the plunger 45.
A hitting coil 48 that drives 2 toward an object to be measured (not shown) and a returning coil 50 that pulls back the hammer 22 are provided.

The hitting coil 48 and the returning coil 50 are provided in the control unit 26.
Is connected to the hammer drive control circuit 28 and is driven and controlled by the hammer drive control circuit 28. On the other hand, the impact sensor 44
Is a piezoelectric element, for example, and is connected by a hammer drive control circuit 28 of the control unit 26 and an abnormality determination circuit 30. The contact between the DUT and the hammer 22 is detected, and a contact detection signal is sent to the hammer drive control circuit 28. It is sent to the abnormality determination circuit 30. The display unit 18 is connected to the abnormality determination circuit 30. The display unit 18 includes, for example, a plurality of light emitting diodes, and displays the presence / absence of abnormality of the object to be measured, the degree of abnormality, and the like.

The contact detection signal of the impact sensor 44, which detects the contact between the hammer head 42 and the object to be measured, is detected by the amplifier 52 as shown in FIG.
After being input to a comparatively 54 via the, and waveform-shaped, it is input to the abnormality determination circuit 30 and the hammer drive control circuit 28. A variable resistor 56 is connected to the comparator 54 so that the reference voltage V ₀ to be compared with the output signal of the amplifier 52 can be changed.

The hammer drive control circuit 28 includes two flip-flops 5
8 and 60, an oscillator 62, a counter 64, and a comparator 66. The output side of the comparator 54 is connected to the reset terminal R ₁ of the flip-flop 58 and the reset terminal S ₂ of the flip-flop 60 via the NOT circuit 68. Also, the oscillator 62
Is connected to the input side of the counter 64, and the counter 6
The output of No. 4 is input to the comparator 66 together with the reference value output from the reference value setting unit 70. Comparator 6
The output of 6 is input to the counter 64 as a reset signal, and is also input to the set terminal S ₁ of the flip-flop 58 and the reset terminal R ₂ of the flip-flop 60.

The output terminals Q ₁ and Q ₂ of the flip-flops 58 and 60 are
Transistor 76 through resistors 72 and 74,
It is connected to the base of 78. Transistors 76, 78
The emitter of is grounded and the collector of the transistor 76 has a striking coil 48 and a flywheel diode 8
0 and 0 are connected in parallel. The flywheel diode 80 has its anode side connected to the collector of the transistor 76 and its cathode side connected to the cathode of the zener diode 82. The anode of the Zener diode 82 is connected to the power supply 84 whose output is variable together with the striking coil 48.

On the other hand, the collector of the transistor 78 is connected with the return coil 50 and the flywheel diode 86 in parallel. The flywheel diode 86 has an anode connected to the collector of the transistor 78 and a cathode connected to the cathode of the zener diode 88. The anode of the Zener diode 88 is connected to the power supply 84 together with the return coil 50.

FIG. 2 shows an example of the abnormality determination circuit 30, which includes a counter 90, an oscillator 92, a controller 94, and a comparator 9.
6 and a memory 98. The counter 90 receives the output of the comparator 54, the pulse signal of the oscillator 92, and the control signal from the control 94, and inputs the output signal to the comparator 96 and the memory 98. Comparator 96
Receives a setting command from the controller 94, and the memory 9
The value written in 8 is fetched as a reference value, compared with the output signal of the counter 90, and the result is displayed on the display unit 18.
Output to. The memory 98 also includes a controller 94.
The write command from is input. Further, the controller 94 is adapted to input a setting signal from the reference value setting button 32, and at the same time the display unit 1
8 and controls the display contents according to the magnitude of the output signal of the comparator 96.

The operation of the impact inspection device configured as described above is as follows.

When a power switch (not shown) is turned on, the hammer drive control circuit 28 of the control unit 26 outputs a drive control signal to the hammer drive unit 24. That is, the hammer drive control circuit 28
The counter 64 counts the pulse signal generated by the oscillator 62 and outputs the count value to the comparator 66 (see FIG. 1). The comparator 66 uses the count value of the counter 64 as a reference value setter 70.
When the count value of the counter 64 reaches the reference value, the pulse is output as shown in FIG. The output signal of the comparator 66 is the flip-flop 5
8 is input as a set signal to the set terminal S ₁ , the reset signal is input to the reset terminal R ₂ of the flip-flop 60, and the reset signal is given to the counter 64.

The flip-flop 58 has a comparator 66 at the set terminal S _1.
When the output pulse of 1 is input, "1" is output from the output terminal Q ₁ by the rising edge a of this output pulse (see FIG. 4). The “1” output from the flip-flop 58 is given to the base of the transistor 76 via the resistor 72 and activates the transistor 76. Therefore, the power source 84
Current flows from the striking coil 48 to the collector and emitter of the transistor 76, and the striking coil 48 generates a magnetic force to drive the hammer 22 toward an object to be measured (not shown).

When the hammer head 42 collides with the object to be measured and gives an impact force to the object to be measured, the impact sensor 44 composed of a piezoelectric element causes the weight 46, the operating rod 47, the inertia force of the plunger 45, and the reaction force from the object to be measured. Is pressed by. Therefore, the impact sensor 44 presses the hammer head 42 until the hammer head 42 starts contacting the object to be measured and is rebounded by the reaction force of the object to be measured and separated from the object to be measured as shown in the upper part of FIG. The contact detection signal corresponding to (reaction force) is output to the amplifier 52. The amplifier 52 amplifies the touch detection signal and outputs an output signal as shown in the middle part of FIG. 5 to the comparator 54.
The comparator 54 compares the input output of the amplifier 52 with the reference voltage V ₀ and outputs a signal having a pulse width equal to the contact time T between the impact sensor 44 and the object to be measured (lower part of FIG. 5).

The signal output from the comparator 54 is input to the abnormality determination circuit 30 and also to the reset terminal R ₁ of the flip-flop 58 of the hammer drive control circuit 28 and the NOT circuit 68. Therefore, the flip-flop 58 causes the rising edge b of the signal from the comparator 54, that is, the hit sensor 4 to operate.
4 is reset by the start of contact between the DUT 4 and the object to be measured, the output from the output terminal Q ₁ becomes “0”, and the operation of the transistor 76 is stopped. As a result, no current flows through the striking coil 48, and the generated magnetic force disappears in the hammer 2
The driving of No. 2 is stopped, and the hammer 22 gives a striking force to the object to be measured only by the inertial force.

The flip-flop 60 has a comparator 54 at the set terminal S _2.
Since the signal from is input through the NOT circuit 68,
Fall c of the signal from the comparator 54 becomes a set signal, a falling c, i.e. hammer 22 outputs "1" from the output terminal Q ₂ by away from the object to be measured. As a result, the transistor 78 operates, a current flows through the return coil 50, and the return coil 50 generates a magnetic force to return the hammer 22.

On the other hand, the counter 64 is reset when the output signal of the comparator 66 is input, and starts counting from 1 again. Then, when the count value of the counter 64 reaches the reference value, the comparator 66 outputs a pulse signal as described above, and the counter 6
4 as a reset signal, the flip-flop 58 as a set signal, and the flip-flop 60 as a reset signal. Therefore, the flip-flop 60 is reset by the rising edge d of the output signal of the comparator 66, the output of the output terminal Q ₂ becomes "0" (Fig. 4e), and the operation of the transistor 78 is stopped to restore it. The magnetic force generated by the coil 50 disappears. At the same time, the set terminal S of the flip-flop 58 is
Inputs an output signal from the comparator 66 to _1, the transistor flip-flop 58 is "1" in the same manner as described above 7
6 is output and the transistor 76 is operated. As a result, a current flows through the striking coil 48, and the hammer 22 is driven toward the object to be measured.

When the hammer 22 collides with the object to be measured, the impact sensor 44 outputs a contact detection signal, and the output of the flip-flop 58 becomes "0" at the rising edge f of the signal from the comparator 54,
The operation of the transistor 76 is stopped and the magnetic force of the striking coil 48 disappears. When the hammer head 42 separates from the object to be measured, the output of the comparator 54 falls as shown in FIG. 4g, the output of the flip-flop 60 becomes "1", and the transistor 78 operates. Therefore, a current flows through the return coil 50 and the hammer 22 is returned. Hereinafter, the same operation is repeated.

Thus, according to the hammer drive control method of this embodiment,
Since the hammer 22 starts contact with the object to be measured and stops driving the hammer 2 at the same time, the hammer 22 gives a striking force to the object to be measured only by the inertial force and is repelled by the repulsive force of the object to be measured, The contact time between the hammer 22 and the object to be measured may correspond to the internal structure of the object to be measured. In addition, the contact detection signal of the impact sensor 44 is
The hammer 22 becomes a signal having a waveform corresponding to the reaction force received from the object to be measured, and it becomes possible to obtain a good signal for waveform analysis. In addition, the hammer 22 separates from the object to be measured, and at the same time, the hammer 22 is returned to the original state.
It is possible to prevent 2 from colliding with the object to be measured again by its own weight, and it is possible to make the contact time between the hammer 22 and the object to be measured completely correspond to the internal structure of the object to be measured.

By changing the set value of the reference value setting device 70,
The number of times of driving the hammer 22 per unit time can be changed, and the number of times of driving per unit time suitable for the speed at which the hammer 22 scans the object to be measured can be selected. When the output of the power supply 84 is changed, the hitting coil 4 is
8. The magnetic flux generated by the return coil 50 changes, and the driving speed of the hammer 22 can be changed.

The presence / absence of abnormality of the object to be measured by the abnormality determination circuit 30 is started by the operation of storing a reference value for determining the presence / absence of an abnormal portion in the memory 98, which is performed as follows.

First, the hammer 22 is driven as described above, and the hammer 22 strikes a reference position, for example, a normal portion of the object to be measured. As a result, the impact sensor 44 is moved to the hammer head 42.
And a normal part of the object to be measured are detected, and a detection signal is sent to the comparator 54 via the amplifier 52. The comparator 54 is
A signal having a pulse width equal to the contact time between the hammer head 42 and the object to be measured is sent to the counter 90 of the abnormality determination circuit 30 (see FIG. 2). The counter 90 starts counting pulses output from the oscillator 92 in response to a rising edge of the signal output from the comparator 54, and ends counting pulses upon a falling edge of the signal output from the comparator 54 to clear the counted value. Output. The controller 94 receives the setting signal when the reference value setting button 32 is pressed, writes the count value output by the counter 90 at that time into the memory 98 as the reference value T _0, and supplies the reference value T ₀ to the comparator 96. , Setting the reference value is completed.

Next, when the hammer 22 starts scanning the object to be measured, the comparator 96 takes in the count value (contact time T) output from the counter 90, and, for example, (T / T ₀ ) / T _0. 1) is calculated and the calculation result is output to the display unit 18. And
When the calculation result of the comparator 96 is smaller than a predetermined value, the controller 94 displays on the display unit 18 that the part of the DUT is normal. In addition, control 94
When the calculation result of the comparator 96 is larger than a predetermined value, the fact that an abnormality such as peeling or crack exists in that portion of the object to be measured is displayed by, for example, turning on a red lamp of the display unit 18 and , Activate a buzzer (not shown) to call the operator's attention.

As described above, the abnormality determining method of the present embodiment can determine whether or not there is an abnormal portion in the measured object by the contact time between the hammer 22 and the measured object, which is extremely easy compared with the conventional method. In addition, it is possible to accurately inspect for abnormalities. In addition, since the spring constant of the object to be measured is large where the core material is present, the contact time between the hammer 22 and the object to be measured is shortened, and the presence or absence of the core material can be inspected by utilizing this.

The presence or absence of abnormality of the object to be measured is determined by analyzing the waveform, for example, by examining the symmetry before and after the peak of the waveform of the contact detection signal of the impact sensor 44 shown in FIG. 5 (A). Can also be done.

The level of abnormality detection, that is, the magnitude of the allowable deviation of the contact time T with respect to the reference value T ₀ can be arbitrarily changed by changing the set value given to the control 94, and the controller 94 is given the set value. Based on the value
The display unit 18 is controlled so that a display corresponding to this is made.

In the above-described embodiment, the case where the hammer 22 is separated from the object to be measured and the return coil 50 is driven to return the hammer 22 at the same time has been described. However, in the case of a single-shot impact rather than continuous impact, the return coil is used. Instead of using 50, you may leave it to natural repulsion. The hammer 22 may be driven by using an electromagnet or compressed air. further,
In the above embodiment, the case where the piezoelectric element is used as the impact sensor 44 has been described, but a piezoresistive element, a strain gauge, or an acceleration sensor may be used.

〔The invention's effect〕

As described above, according to the present invention, by stopping the driving of the hammer at the same time when the contact between the hammer and the object to be measured is started, the hammer gives the hammering force to the object to be measured only by the inertial force. A waveform signal that allows the contact time with the DUT to correspond to the internal structure of the DUT, and that corresponds to the reaction force from the DUT received corresponding to the striking force applied to the DUT by the hammer. Therefore, it is possible to easily determine whether or not there is an abnormality in the measured object.

[Brief description of drawings]

FIG. 1 is a circuit diagram of drive control for implementing a drive control method of a hammer for hammering inspection according to an embodiment of the present invention, and FIG. 2 is a circuit showing an example of an abnormality determination circuit of a hammering inspection apparatus to which the embodiment is applied. 3 and FIG. 3 are configuration explanatory views of a percussion inspection device to which the embodiment is applied, FIG. 4 is a timing chart illustrating a drive control method according to the embodiment, and FIG. 5 is a waveform of a contact detection signal of a percussion sensor. It is explanatory drawing of a shaping procedure. 22 ... Hammer, 24 ... Hammer drive unit, 26 ... Control unit, 28 ... Hammer drive unit control circuit, 30 ... Abnormality determination circuit, 42 ... Hammer head, 44 ... Impact sensor, 4
8 ... Hitting coil, 50 ... Return coil, 54, 6
6, 96 ... Comparator, 58, 60 ... Flip-flop, 62, 92 ... Oscillator, 64, 90 ... Counter,
94 ... Controller.

Claims (1)

[Claims] 1. A driving control method for a hammer for striking an inspection, which drives a hammer for applying a striking force to an object to be measured, wherein the hammer separated from the object to be measured is driven toward the object to be measured, and the hammer is A driving control method for a hammer for hitting inspection, wherein the driving of the hammer is stopped by detecting that the contact with the object to be measured is started.