JP4671518B2 - Screw tightening monitoring system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmitter or receiver-equipped tool, a position detection system thereof, and a work monitoring system, and in particular, a tool equipped with a transmitter or a receiver such as drilling, screwing, and polishing having an ultrasonic transmission function, The present invention relates to a position detection system that detects an operating position of the tool, and a monitoring system that monitors work performed using the tool.
[0002]
[Prior art]
Conventionally, operations such as screw tightening have been performed on various objects using a tool such as an electric screwdriver. The screw tightening work is indispensable for manufacturing various devices. For example, from the screw tightening of small devices such as personal computers, printers, VTR casings, etc., for example, vehicle and airplane engine components, etc. Tightening is performed in a wide range of fields, including screw tightening of large equipment.
[0003]
Screw tightening is a seemingly trivial task. However, if you forget to tighten the screws in one place as described above, or if the screw tightening torque is larger or smaller than the specified value, the device has been used for many years. In the meantime, the shape of the housing may be deformed or the operation of the engine may become unstable, which is an important task.
[0004]
For this reason, in the screw tightening operation of various devices, it is checked whether all the predetermined locations have been tightened, whether the screws have been tightened in a predetermined order, or whether the screws have been tightened with a predetermined tightening torque. Has been done.
[0005]
[Problems to be solved by the invention]
However, it can be visually checked by a third party such as the person in charge of the operation whether the screws are tightened at all of the predetermined portions, but the screws are tightened in a predetermined order. There was a problem that it was virtually unchecked whether or not it had been checked by the self-report of the worker. In addition, there is a problem that a mistake may occur because the above check is performed manually, and there is a problem that labor efficiency is high and work cost is high.
[0006]
An object of the present invention is to solve the problems described above, it is to provide a monitoring system of the work and screwing operation can be easily monitored.
[0007]
In order to achieve the above-described object, the present invention provides a screw tightening tool having an ultrasonic transmission unit in a screw tightening monitoring system that automatically checks whether screw tightening has been performed in a predetermined order. A means for detecting the screw tightening position of the screw tightening tool, including three or more ultrasonic receivers arranged around the work space of the screw tightening tool, and the position of the screw tightening tool in time series Means for storing; work procedure data in which positions and sequences to be screwed with the screw tightening tool are registered in advance; comparison means for comparing the movement of the position of the screw tightening tool with the work procedure data; It is characterized in that it comprises means for issuing an alarm when the comparison means detects a mismatch . According to this feature, the operator's work procedure using the tool can be automatically monitored.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1A is a conceptual diagram of one embodiment of the present invention.
[0011]
Now, assuming that there is a work space for screwing the casing 1 of an electrical device or the like, the ultrasonic receivers 2a, 2b, 2c are provided at least at three places (four places in the illustrated example) around the space. , And 2d. When the work space is a wide space that allows a series of work to flow and work, as shown in the drawing, the ultrasonic receiver has poles 3a around at least three places around the work space to be screwed. To 3d, and the ultrasonic receivers 2a to 2d are fixed to the upper portions of the poles. If there is a pillar nearby, this pillar may be used. On the other hand, when the work space is a private room, the ultrasonic receivers 2a to 2d can be fixed to the four corners of the ceiling.
[0012]
The electric driver 4 that is a tool for screwing the casing 1 is driven by power supplied from a power source 5. The electric driver 4 can be of a known structure, except that it has an ultrasonic transmission unit 6 that transmits an ultrasonic wave at the same time when the start switch is pressed. The timing of transmitting the ultrasonic wave may be other timing such as before the electric driver 4 is operated or when it is stopped. In order to transmit the ultrasonic wave before the operation of the electric driver, the configuration of the electric driver 4 is set so that the ultrasonic wave is transmitted when the start switch is pressed, and then the electric driver starts operating after a short delay. That's fine.
[0013]
When an ultrasonic wave is transmitted from the ultrasonic wave transmission unit 6 of the electric driver 4, the ultrasonic wave propagates in all directions and is received by the ultrasonic receivers 2a to 2d. It is obvious that the time received by the ultrasonic receivers 2a to 2d is a function of each distance between the ultrasonic transmission unit 6 of the electric driver 4 and the ultrasonic receivers 2a to 2d.
[0014]
Signal analysis units 11a to 11d are connected to the ultrasonic receivers 2a to 2d, respectively. The signal analysis units 11a to 11d are connected between the ultrasonic receivers 2a to 2d and the ultrasonic transmission unit 6. The distance is calculated. The distance information obtained by the signal analysis units 11 a to 11 d is sent to the overall processing unit 12. The overall processing unit 12 excludes erroneously detected information from the input three or more pieces of distance information, and detects the position of the electric driver 4, that is, the screwing position of the housing 1 from the correct distance information.
[0015]
Since the detection information of the screwing position is sequentially detected as the screw tightening operation of the housing 1 proceeds, the overall processing unit 12 stores the detection information in a memory in time series. Accordingly, as shown in FIGS. 1B and 1C, the A side of the housing 1 is in the order of 1 → 2 → 3 → 4 and the B side is in the order of 5 → 6 → 7 → 8. Whether the screw has been tightened can be known by referring to the detection information stored in the memory. Further, the data of the order of screw tightening such as the A side and B side is stored in advance in the memory as reference data, and the order is compared with the reference data every time the operator performs screw tightening. If the alarm section (alarm) 13 is activated at that time if it happens, the worker's work can be checked in real time.
[0016]
Next, the reason why the signal analyzers 11a to 11d can determine the distance from each of the ultrasonic receivers 2a to 2d to the working electric driver 4 will be described with reference to FIG. FIG. 2 is a plan view of FIG. 1 viewed from above.
[0017]
As shown in the figure, assuming a coordinate system in which the x, y, and z axes are orthogonal to each other, the ultrasonic receivers 2a to 2d are respectively known positions (x1, y1, z1), (x2, y2, z2). ), (X3, y3, z3), and (x4, y4, z4). If the start button of the electric driver 4 is pressed at a certain time t0, an ultrasonic wave is transmitted from the ultrasonic transmission unit 6 at the time t0. Thereafter, when the ultrasonic waves reach the ultrasonic receivers 2a to 2d, the signal analyzers 11a to 11d can detect the time when the ultrasonic waves are received. At this time, the time t0, that is, the start signal m is sent to the reception analysis units 11a to 11d via the start detection unit 5a of the electric driver 4 provided in the power source 5 when the start button of the electric driver 4 is pressed. It shall be notified by wire. The start detection unit 5a starts the electric driver 4 by detecting, for example, a change in current supplied from the power source 5 to the electric driver 4 or by detecting a trigger pulse from a logic circuit linked to the start button. Can be detected.
[0018]
Assuming that the time when the signal analysis units 11a to 11d receive the ultrasonic waves is t1, t2, t3, and t4, t4-t0, t3-t0, t2-t0, t1-t0 are the ultrasonic receivers. Since the ultrasonic propagation time difference Δt between 2a to 2d and the electric driver 4 is obtained, the ultrasonic receiver 2a to 2d and the electric driver can be obtained by multiplying Δt by the propagation velocity v (about 340 m / sec) of the ultrasonic wave in the air. The distance difference between 4 is obtained. Generally, if three or more distance differences are obtained in a three-dimensional space, the position of the electric driver 4 with respect to the ultrasonic receivers 2a to 2d can be specified as one point, and therefore the position of the electric driver 4 is obtained. become.
As another method, a light emitting element (for example, a photodiode) or a radio wave transmitter is disposed at the same position as or near the ultrasonic transmission unit 6 of the electric driver 4, and at least one of the ultrasonic receivers 2a to 2d. One method may be provided with a light or radio receiver. That is, when the start button of the electric driver 4 is pressed and at the same time the ultrasonic transmitter 6 and the light emitting element or radio wave transmitter are operated, the speed of light or radio wave is almost the same as the propagation speed of the ultrasonic wave. Since it is infinite, if the time when the light or radio wave is detected by the light receiving element or the radio wave receiver is compared with the ultrasonic wave reception time of each of the ultrasonic wave receivers 2a to 2d, the super The required propagation time ti of the sound wave to each of the ultrasonic receivers 2a to 2d is obtained. Therefore, by multiplying ti by the propagation velocity v of the ultrasonic wave, the distance between the ultrasonic receivers 2a to 2d and the electric driver 4 is obtained, and the position of the electric driver 4 is uniquely obtained from the distance. It will be.
[0019]
As described above, according to the present embodiment, the position and the order of screw tightening with the electric screwdriver can be detected, so that the screw tightening is not performed or the screw tightening is not performed at the position to be screwed. This can be easily discovered if the order is different. In addition, when the worker does not perform the predetermined screw tightening during the work, an alarm can be issued and the work can be restarted.
[0020]
Next, a second embodiment of the present invention will be described. In this embodiment, in the first embodiment, if another similar tool that generates ultrasonic waves is used in the work space or in the vicinity thereof, a malfunction may occur in detecting the position of the tool. This is an improvement on this fear.
[0021]
In this embodiment, an ultrasonic transmitter 30 that outputs a spread spectrum-modulated ultrasonic signal is used as the ultrasonic transmitter 6 of the electric driver 4. On the other hand, as the ultrasonic receivers 2a to 2d, an ultrasonic receiver 40 that despreads and demodulates received signals is used.
[0022]
FIG. 3 is a block diagram illustrating a configuration of a specific example of the ultrasonic wave transmitting unit 30. For example, the binary code generator 31 multiplies the data including the identification number given to the electric driver 4 by a pseudo noise code (PN code) having a value of +1 or -1. The PSK modulator 32 uses the carrier wave supplied from the carrier wave generator 33 to spread-modulate the output signal from the binary code generator 31 simultaneously with narrow band modulation. The modulation signal from the PSK modulator 32 is sent to the ultrasonic transmitter 34 and transmitted by ultrasonic waves.
[0023]
Next, the configuration of a specific example of the receiver ultrasonic wave 40 will be described with reference to the block diagram of FIG. The ultrasonic signal transmitted from the ultrasonic transmitter 30 is received by the ultrasonic receiver 41 and sent to the mixer processor 42. The mixer processing unit 42 performs frequency conversion using the carrier wave from the carrier wave generator 43 and sends the frequency-converted signal to the correlation processing unit 44. The correlation processing unit 44 obtains the same pseudo noise signal as that used in the binary code generator 31 of the ultrasonic transmission unit 30 from the binary code generator 45, despreads it, and demodulates it.
[0024]
According to this embodiment, even if a plurality of electric drivers are operating in parallel in the work space or in the vicinity thereof, if the pseudo-noise code of each electric driver is different, the ultrasonic receiver There is an advantage that the position of the electric driver can be detected individually. Even if ultrasonic noise is emitted from other peripheral devices, the position of the electric driver is not erroneously detected.
[0025]
Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, the ultrasonic transmitters 51, 52, 53, and 54 are arranged at least at three places (four places in the illustrated example) around the work space in which a casing of an electrical device or the like is screwed. On the other hand, an ultrasonic receiving unit 60 is provided in a part of the electric driver 4, and the receiving unit 60 receives signals sequentially transmitted from the ultrasonic transmitters 51 to 54 in time series, and analyzes the signals. Thus, the position of the electric driver 4 is detected. In FIG. 5, the same reference numerals as those in FIG. 1 denote the same or equivalent components. In addition, when the ultrasonic transmitters 51, 52, 53, and 54 are triggered, they operate for the time t1 and transmit ultrasonic signals 51a, 52a, 53a, and 54a, respectively.
[0026]
When the electric driver 4 is activated, the start signal m output from the start detector 5a of the electric driver 4 is input to the ultrasonic transmitter 51, and the ultrasonic transmitter 51 is triggered. Thereby, the ultrasonic signal 51a is transmitted from the ultrasonic transmitter 51 for t1 time. Next, the start signal m is delayed by t0, and is input to the ultrasonic transmitter 52 to trigger the ultrasonic transmitter 52. At this time, since t1 <t0, the ultrasonic transmitter 52 starts transmitting the signal 52a after the ultrasonic transmitter 51 finishes transmitting the ultrasonic signal 51a, and both ultrasonic signals 51a. , 52a are avoided. Similarly, the ultrasonic transmitters 53 and 54 transmit the ultrasonic signals 53a and 54a with a delay of t0 time, respectively.
[0027]
FIG. 6 shows a timing chart of the received signal of the receiver 60. The receiver 60 starts receiving the signals 51a, 52a, 53a, and 54a after times T0, T1, T2, and T3 from the start of the electric driver 4, respectively. The reception signals 51a to 54a received by the receiver 60 are sent to the signal analysis unit 61, and times T0, T1, T2, and T3 from the start of the electric driver 4 to the reception by the receiver 60 are obtained. . The signal analysis unit 61 obtains the distances r1, r2, r3, and r4 between the ultrasonic transmitters 51 to 54 and the electric driver based on the times T0, T1, T2, and T3. These distances r1, r2, r3, and r4 are vT0, v (T1-t0), v (T2-2t0), and v (T3-3t0), where v is the propagation velocity of the ultrasonic signal space. Is required.
[0028]
The distances r1, r2, r3, and r4 obtained by the signal analysis unit 61 are sent to the overall processing unit 62. The overall processing unit 61 performs the same or equivalent processing as the overall processing unit 12 in FIG. That is, among the input three or more pieces of distance information, erroneously detected information is excluded, and the position of the electric driver 4, that is, the screwing position of the housing is detected from the distance information considered to be correct.
[0029]
The timing at which the electric driver 4 receives the ultrasonic wave may be any time before the electric driver 4 is operating, during operation, or at the time of stopping.
[0030]
Next, as a modification of the third embodiment, a spectrum-spread ultrasonic signal may be transmitted from the ultrasonic transmitters 51 to 54. The ultrasonic transmitters 51 to 54 generate different binary codes in the binary code generator 31 of FIG. On the other hand, on the receiving side, the number of the correlation processing units 44 having the same binary encoder 45 as that used in the ultrasonic transmitters 51 to 54 is provided in parallel by the number of the ultrasonic transmitters 51 to 54 to perform pseudo spread code analysis. By performing the above, the transmission signals of the ultrasonic transmitters 51 to 54 can be identified. In this case, since the ultrasonic transmitters 51 to 54 can simultaneously transmit signals, the delay t0 in FIG. 5 is unnecessary. In the third embodiment, the timing when the start button of the electric driver is pressed is notified by wire, but may be notified wirelessly by light or radio waves. Next, a fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the ultrasonic transmission unit 6 of the electric driver 4 continuously transmits a signal that is continuously modulated with a pseudo spread code according to an internal reference clock. At this time, the reference clocks in the receivers 2a to 2d or the reception correlation calculation units 71a to 71d are synchronized with the internal clock of the ultrasonic transmission unit 6 by radio (q) such as wired or light / radio wave. For example, the ultrasonic transmission unit 6 of the electric driver 4 outputs the repetitive spread spectrum code S (t) 72 shown in FIG. On the other hand, the receivers 2 a to 2 d or the correlation calculation units 71 a to 71 d generate the same signal 72 ′ as the signal 72 in synchronization with the ultrasonic wave transmission unit 6. At this time, the signal 72 ′ is S (t−Δt), and the value of Δt is sequentially changed to perform correlation calculation with the received signal S (t−T) 73. When Δt matches T, the correlation calculation units 71a to 71d give a large correlation value, and therefore determine the value of T at that time.
[0031]
Since the phase difference T corresponds to the propagation time of the ultrasonic signal from the ultrasonic wave transmission unit 6 of the electric driver 4 to the receivers 2a to 2d, the phase difference T is multiplied by the propagation velocity v of the ultrasonic wave in the air. Thereby, each distance between the electric driver 4 and the receivers 2a to 2d can be obtained. If the distance is obtained, the position of the electric driver 4 can be obtained as in the above-described embodiments.
[0032]
In this embodiment, since the clock of the transmitter 6 and the receivers 2a to 2d are synchronized, the start signal m is not particularly required, but a constant signal q for synchronization may be transmitted periodically. I need it.
[0033]
As a modification of this embodiment, as in the third embodiment, the ultrasonic transmitter 6 may be an ultrasonic receiver and the receivers 2a to 2d may be ultrasonic transmitters.
[0034]
In each of the above-described embodiments, the electric driver has been described as an example. However, the present invention is not limited to the electric driver, and is not limited to the electric driver. It can also be applied to other tools such as drilling machines. Also, a pneumatic tool or a manual tool may be used. Further, a tool such as binding, caulking, or rivet may be used. Furthermore, it can be applied to automatic machines and robots.
[0035]
【The invention's effect】
As is clear from the above description, according to the present invention, since the ultrasonic wave can be transmitted from the tool, the operation procedure of the tool can be reduced by receiving this with at least three ultrasonic receivers. Can be detected.
[0037]
In addition, since an ultrasonic signal can be received by the tool, the tool receives signals transmitted from ultrasonic transmitters disposed at least at three or more places around the working position of the tool. The work position can be detected.
[0038]
In addition, by storing the work position of the tool in time series, a work history can be recorded. Further, the work can be monitored by comparing predetermined work procedure data with the work history. In addition, when there is an error in the work procedure, an alarm can be issued to allow the worker to follow the correct procedure.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a schematic configuration of a first embodiment of the present invention.
FIG. 2 is a plan view of FIG. 1 viewed from above.
FIG. 3 is a block diagram illustrating a configuration of an example of an ultrasonic wave transmission unit.
FIG. 4 is a block diagram showing a configuration of an embodiment of an ultrasonic receiver.
FIG. 5 is a system diagram showing a schematic configuration of a third embodiment of the present invention.
FIG. 6 is a timing chart of reception signals of the ultrasonic receiver.
FIG. 7 is a system diagram showing a schematic configuration of a fourth embodiment of the present invention.
FIG. 8 is an explanatory diagram of a phase difference between transmission and reception signals.
[Explanation of symbols]
2a-2d ... ultrasonic receiver, 6 ... ultrasonic transmitter, 11a-11d, 61 ... signal analyzer, 12, 62 ... general processing unit, 13, 63 ... alarm unit 51-54 ... Ultrasonic transmitter, 60 ... Receiver, 71a-71d ... Correlation calculator.

Claims (5)

In a screw tightening monitoring system that automatically checks whether screw tightening has been performed in a predetermined order,
  A screw tightening tool having an ultrasonic transmitter;
  Means for detecting a screw tightening position of the screw tightening tool, including three or more ultrasonic receivers arranged around a work space of the screw tightening tool;
  Means for storing the position of the screw tightening tool in time series;
  Work procedure data in which positions and orders to be screwed with the screw tightening tool are registered in advance;
  Comparison means for comparing the movement of the screw tightening tool and the work procedure data;
  A screw tightening work monitoring system comprising: means for issuing an alarm when the comparison means detects a mismatch. The screw tightening monitoring system according to claim 1,
The ultrasonic wave transmitted from the screw tightening tool is received by the three or more ultrasonic receivers, and the screw tightening tool and the three are based on the transmission, the reception timing, or the phase difference between the transmitted and received signals. A screw tightening work monitoring system characterized in that the distances between the ultrasonic receivers described above are obtained, and the position of the screw tightening tool is detected from the distances. The screw tightening monitoring system according to claim 1,
The ultrasonic signal transmitted from the screw tightening tool is received by the three or more ultrasonic receivers, and the received signal is subjected to inverse spectrum conversion and demodulated, based on the transmission and reception timing of each received signal. A system for monitoring a screw tightening operation , wherein each distance between a screw tightening tool and the three or more ultrasonic receivers is obtained, and a position of the screw tightening tool is detected from the distance. The screw tightening monitoring system according to claim 2 or 3,
The transmission timing monitoring system according to claim 1, wherein the transmission timing is notified to the ultrasonic receiver by a wire that transmits a state signal of the screw tightening tool. The screw tightening monitoring system according to claim 1,
The screw tightening tool further comprises a light emitting part or a radio wave transmitting part,
At least one of the ultrasonic receivers is provided with a light receiving unit or a radio wave receiving unit, and ultrasonic waves and light transmitted from the screw tightening tool by the three or more ultrasonic receivers and the light receiving unit or the radio wave receiving unit. Alternatively, a radio wave is received, and each distance between the screw tightening tool and the three or more ultrasonic receivers is determined based on the reception timing of the ultrasonic wave and the reception or reception timing of the light or the radio wave, A screw tightening work monitoring system, wherein the position of the screw tightening tool is detected from a distance.

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