JP3194332B2 - Simple body measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple vehicle body measuring apparatus capable of monitoring and analyzing a vehicle body accuracy defect in its own process.

[0002]

2. Description of the Related Art In assembling a vehicle body, it is extremely important to guarantee the quality of the body (dimensional accuracy, appearance quality, welding quality). Conventionally, there is a process dedicated to quality inspection according to the process of the body. , Guaranteeing the quality to the next process.

For example, taking a welding process as an example, conventionally, a dedicated measuring robot having high positioning accuracy is arranged in a dedicated measuring process subsequent to the welding process, and various sensors are attached to the measuring robot. The data processing is performed using an engineering workstation (EWS), and these are comprehensively controlled by a control system dedicated to the measuring device. FIG. 8 shows a specific configuration example of such a system. In the figure, "1" is an assembly body, "2" is a transport device, "3" is an NC locator positioning device, "4" is a measuring robot, "5" is a laser scanning distance measuring device, and "6" is Image sensor, “7” is NC locator control panel, “8” is body measurement control panel, “9”
Is a teaching board, "10" is EWS, "11" is a monitor PC
It is.

[0004]

However, in such a conventional vehicle body measuring system, a dedicated process for measurement must be provided separately from the welding process, which increases the cost. In particular, it is not realistic in terms of cost and space to provide a dedicated measurement step after every step. Further, the use of the EWS 10 having a high cost per unit as a data processing device is also a major factor in increasing the cost.

[0005] In addition, since the body after welding is measured in the process dedicated to measurement, measurement data before and after welding cannot be compared, and it is not possible to track a change in accuracy of the body before and after welding. Therefore, it is difficult to grasp the effect of welding on the body accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and it is an object of the present invention to provide a simple vehicle measuring apparatus capable of monitoring and analyzing a vehicle body accuracy defect in its own process.

[0007]

In order to achieve the above object, in a simplified vehicle measuring apparatus according to the present invention, a measuring sensor attached to a welding robot equipped with a welding gun and output data of the measuring sensor are provided. Data processing means for processing, a fixed origin member for assuring the accuracy of body measurement by the measurement sensor, and first correction means for calculating position correction data by comparing data obtained by measuring the origin member with initial data. A second correction unit that corrects a body measurement position by the measurement sensor based on the position correction data, and a control unit that controls the welding robot so that the measurement sensor comes to a predetermined body measurement position.
It has.

[0008] The measurement sensor is connected to data processing means via an interface board to which a plurality of sensors of the same type can be connected.

In order to protect the measurement sensor, it is preferable to provide an openable and closable shutter for protecting the lens surface of the measurement sensor, and a motor or a fluid pressure cylinder for driving the shutter to open and close. As a drive mechanism of the shutter, instead of a motor or a fluid pressure cylinder, a coil for converting a change in a magnetic field generated during welding into a current, an electromagnet connected to the coil, and a spring connected to the shutter and attached to the electromagnet. A movable piece may be provided facing the member via a member, or a nozzle may be provided for injecting air at the time of pressurization supplied to the pressurizing cylinder of the welding gun toward the shutter.

[0010]

In the simple body measuring apparatus constructed as described above, since the measuring sensor is attached to the welding robot together with the welding gun, the body measurement before and after welding can be performed in the welding process. In actual body measurement, first measure the origin member with a measurement sensor,
After the position correction data is calculated by comparing the data obtained by measuring the origin member by the first correction means with the initial data, the body measurement position by the measurement sensor is corrected by the second correction means based on the position correction data. The control means controls the welding robot so that the measurement sensor comes to the corrected body measurement position. Then, the measurement sensor moved to the predetermined body measurement position measures the body, and the data processing means processes output data of the measurement sensor.

When the measurement sensors are connected to the data processing means via the interface board, all the measurement sensors to be used are associated with the parameters, so that the number and types of the measurement sensors can be easily changed. .

When a shutter is provided to protect the measurement sensor, the shutter is opened and closed by a drive source so as to close during welding and open during measurement. As a drive source, a motor or a fluid pressure cylinder may be directly driven, a magnetic field generated at the time of welding may be used, or pressurized air supplied to a welding gun may be used.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of one embodiment of the present invention, FIG. 2 is a configuration diagram of a data processing system, FIG. 3 is a diagram for explaining a data structure, FIG. Is a flowchart of a measurement position correction process, FIG. 6 is a structural diagram of a sensor with a shutter, FIGS. 7 to 9 are diagrams showing another embodiment of the sensor protection mechanism, and FIG. 10 is a further embodiment of the sensor protection mechanism. FIG. 11 is a diagram for explaining a statistical data processing method. Note that parts common to those in FIG. 8 are denoted by the same reference numerals.

The present system shown in FIG. 1 is capable of performing body measurement in a body welding process, and includes a welding robot 15 (hereinafter simply referred to as a robot),
A measurement sensor 16 attached to the robot 15;
A personal computer 17 for processing data output from the measurement sensor 16 and a robot control panel 18 for controlling the robot 15
A line control panel 19 for comprehensively controlling the system;
It is composed of a fixed origin post 20 for guaranteeing measurement accuracy. The robot 15 is further provided with a welding gun 21. In this embodiment, the welding gun 21 of the robot 15 is provided with various measuring sensors (for example, displacement sensors, image sensors, etc.).
The origin member is constituted by an origin post 20, the data processing means, the first correction means and the second correction means are constituted by a personal computer 17, and the control means is constituted by a robot control panel 18 and a line control panel 19.

The above-described system solves the above-mentioned problems. The necessary conditions for this purpose are that measurement can be performed in the welding process and that the data processing system can be configured at low cost. In order to realize these, the following technical problems must be solved. 1. Since the type and number of parts to be measured vary depending on the process, the number and type of sensors, robots, and the like must be widely applicable. 2. Since various robots and welding devices are installed on the vehicle body assembly line and an actuator for moving the sensor cannot be freely selected, three-dimensional coordinates unique to the device cannot be provided. 3. In order to attach sensors to welding robots and welding equipment, it must be able to cope with changes in accuracy due to environmental temperature and self-heating. 4. Since the measuring sensor is constantly exposed to spatter during welding, the sensor must be protected. 5. Data processing system, not on expensive EWS,
Although there are many restrictions such as memory, it must be built on an inexpensive personal computer. 6. A measurement control system must be developed for each process.

In this embodiment, the following solutions are taken for each of the above technical problems.
Hereinafter, they will be described in order.

First, for technical problem 1, the data processing system is being generalized. In other words, all the items that can be changed can be input using parameters, from the number and types of measurement sensors to communication with the sensor movement actuator.

FIG. 2 shows an example of the configuration of such a data processing system. Various sensors 16 (types A, B,
C) is a dedicated interface board 22
It is connected to the personal computer 17 via (A, B, C). A plurality of sensors 16 of the same type can be connected to each interface board 22. PC 17
A program (software interface) 23 for comprehensively controlling each interface board 22 is stored in a memory unit in the inside. On the other hand, the robot 15, the welding device 30, and the line control panel 19 are connected to the personal computer 17 via a common interface board 24. In another memory unit in the personal computer 17, a program (software interface) 25 for controlling the interface board 24 is stored. Thus,
On the sensor data input side, the various sensors 16 are associated with the parameters of the software interface 23 via the respective interface boards 22. On the actuator communication side, the robot 15 and the like correspond to the parameters of the software interface 25 via the interface 24. It is attached. Therefore, various sensors 1
When the number and type of the robots 6 and the robot 15 are changed, it is possible to easily cope with them by changing the parameters of the software interfaces 23 and 25.

Regarding the technical problem 2, the data structure is simplified. In other words, the data is not stored in three dimensions, but is stored in one or two dimensions, and the comparison value of the difference from the master data is used as measurement data, so that it is not necessary to define the three-dimensional absolute coordinate system of the individual actuator. is there.

The data structure of this embodiment will be described by taking a one-dimensional laser displacement sensor (in the case of a distance measuring range of 100 mm) as an example. 3 (A) is a view of the state at the time of measurement as viewed from above, FIG. 3 (B) is a cross-sectional view taken along the line BB of FIG. 3 (A), and “12” in FIG. It is.
In this case, the laser displacement sensor 16 is set so as to approach the panel surface substantially at right angles by robot teaching. Regarding the detection value (displacement amount data) of the laser displacement sensor 16 at a predetermined measurement position, if the displacement amount data with respect to the master body (solid line) as a reference is L0, and the displacement amount data with respect to the actual production body (dotted line) is L1. The distance between the laser displacement sensor 16 and the roof panel 12 is 100 + L0 (mm) in the former case, and 100 + L1 (mm) in the latter case (see FIG. 3B). In this system, measurement data is stored in master data L0
, That is, measurement data = L1−L0.

Regarding the technical problem 3, a system for assuring measurement accuracy is being constructed. That is, by measuring the fixed origin post 20 for each cycle, the amount of deviation from the time of master data measurement is calculated, and the body measurement position is always corrected to correct the change due to the environment (temperature). Hereinafter, this point will be described in detail.

First, an outline of the correction method will be described using the robot 15 as an example. First, the robot 15
Of the robot 1 at each measurement position including the origin measurement (for example, arm length, axis configuration, etc.)
The angle of each axis of No. 5 is registered. Then, as an origin post measurement step, the robot arm length elongation ΔM is obtained from the deviation amount of the measurement data, and correction data is created. then,
In the actual measurement stage, the current position data of the sensor 16 is calculated using the axis angle data for each measurement site, and the difference from the ideal value in the robot coordinate system is obtained.
And outputs the corrected measurement position command.

The method of measuring the origin post is as follows. That is, for example, in a system having a first origin post 20a and a second origin post 20b as shown in FIG. 4, the first origin post measurement is for knowing the extension of the first arm 26 of the robot 15 (at this time, the sensor 16 is at the position of the solid line), the distance M01 and the arm length M1 at room temperature.
Is stored, and the arm length extension ΔM1 is estimated from these data and the distance M01 at the time of measurement. Similarly, the second
The origin post measurement is for knowing the extension of the second arm 27 of the robot 15 (at this time, the sensor 16 is at the position indicated by the dotted line). The distance M02 and the arm length M2 at room temperature are stored, and these data and measurement are performed. From the distance M02 at the time, the arm length extension ΔM2 is estimated. Then, by giving the estimated data ΔM1 and ΔM2 as parameters to the correction matrix, a correction value in the robot coordinate system is calculated.

FIG. 5 is a flowchart of such a correction process. In a state where the basic characteristic value of the robot 15 and the angle (initial data) of each axis of the robot 15 at each measurement position are registered, the above-mentioned origin post measurement is performed (S
1) The microcomputer 17 calculates the measured data (M01: M0
2) and initial data (M01, M1) stored in advance.
: M02, M2), the arm length elongation (ΔM1, ΔM2) as an error is calculated (S2). Then, it is determined whether the error obtained in step 2 is below the standard (S
3) If so, the robot 15 is moved to a predetermined measurement position to perform normal measurement (S4), and then the process returns.

On the other hand, if the result of the determination in step 2 is that the error exceeds the standard, the microcomputer 17 creates a correction matrix based on the error (S5). Then, waiting for the input of the measurement command (S6), the name of the measurement site is acquired (S7), and the correction value of the measurement position in the robot coordinate system based on the correction matrix created in step 5 and the registered axis angle. And sends the correction value to the robot control panel 18 (S8). Robot control panel 1
8 corrects the measurement position command based on the correction value, and issues the corrected measurement position command to the robot 15 (S9). Then, the robot 15 moves to the measurement position and performs a measurement operation (S10), and returns.

Regarding the technical problem 4, protection of the measurement sensor and safety measures are taken. FIG. 6 shows an embodiment of the present invention.
A shutter 36 is attached to the shutter 5, and the shutter 36 is opened during measurement, and the shutter 36 is closed during standby to protect the sensor 16. In addition, the laser displacement sensor 1
In the case of 6, it is dangerous if the laser beam enters the eyes directly,
The provision of the shutter 36 also serves as a shield,
Safety is ensured. FIG. 2A is a conceptual diagram showing two laser displacement sensors attached to a robot, and FIG.
And (C) are a front view and a side view conceptually showing the structure of the laser displacement sensor, respectively. 6B and 6C,
"37" is a shutter take-up motor, "38" is a take-up car,
“39” is a guide roller, and “40” is an amplifier. As a method of directly driving the shutter 36, a fluid pressure cylinder (for example, a pneumatic cylinder) is used instead of the motor 37.
May be used.

When the shutter 36 is driven by the motor 37 or the pneumatic cylinder in this way, the mechanism or mechanism is simple, but wiring or piping is required to supply power to the shutter 36. Wiring or piping must be performed each time the device is mounted on the device, which tends to increase the number of installation steps.

Therefore, in the embodiments shown in FIGS. 7 to 9, the shutter is opened and closed using a magnetic field generated at the time of welding. The outline of this mechanism is as shown in FIG. A coil device 5 is mounted on the arm 21a of the spot welding gun 21.
0 is attached. This coil device 50 is shown in FIG.
As shown in FIG.
, And a coil 52 wound around a predetermined position of the coil mounting member 51. The coil mounting member 51 functions as a magnetic core. The coil 52 is a rectifier circuit 53
Is connected to the electromagnet 54 via the. Rectifier circuit 53
Is composed of, for example, a single-phase bridge rectifier circuit. A capacitor 55 is connected in parallel between the rectifier circuit 53 and the electromagnet 54 to smooth the current rectified by the rectifier circuit 53. Also, at the position facing the electromagnet 54,
A movable piece 57 urged by a spring 56 is disposed. The movable piece 57 moves against the spring force by the attraction force of the electromagnet 54. A shutter 58 is connected to the movable piece 57.
The shutter 58 opens and closes the 6A lens surface. A specific example of the portion C in FIG. 7 is as shown in FIG. Here, utilizing the attractive force of the electromagnet 54,
The shutter 58 is configured to open and close around a fulcrum 59. In FIG. 9, “56A” is a leaf spring, and “6A” is
"0" is a shutter opening stopper.

Next, the operation of this mechanism will be described. When the work (workpiece) is pressurized and energized by the spot welding gun 21, a magnetic field is generated in the magnetic core 51, an induced electromotive force is generated in the coil 52, and an induced current flows. This induced current is rectified by the rectifier circuit 53 and then supplied to the electromagnet 54 to excite the electromagnet 54. Then, since the movable piece 57 is attracted by the electromagnet 54 against the spring 56 (or the leaf spring 56A), the shutter 58 operates to close the lens surface of the measurement sensor 16A (the state of the solid line in FIG. 9). Thereby, the measurement sensor 16A is protected from spatter during welding. When the energization ends, the magnetic field generated in the magnetic core 51 disappears, so that no induced current flows through the coil 52, and the electromagnet 54
Degauss. Then, the spring 56 (or the leaf spring 56A)
The movable piece 57 returns to the original position due to the restoring force of (1), so that the shutter 58 operates to open the lens surface of the measurement sensor 16A (the state shown by the dashed line in FIG. 9). As a result, the measurement sensor 16A is ready for measurement.

According to this mechanism, wiring and piping for opening and closing the shutter 58 are not required. In addition, since a change in the magnetic field generated during welding is used as a power source, energy can be saved.

FIG. 10 is a schematic view showing still another embodiment. In this embodiment, the opening and closing operation of the shutter is performed using the air at the time of pressurization. That is, the spot welding gun 21 is provided with a pressurizing cylinder 70 (for example, an air pressurizing type), and the pressurizing cylinder 70 is supplied with air from a pneumatic pressure source 71 via a pipe 72. . Air for pressurization is supplied via a pipe 72a, and when pressurization is completed, air is supplied via a pipe 72b to return the cylinder 70 to a non-pressurized state. Switching of air is performed by a switching valve 73. A bypass pipe 74 is connected to the pressurized air pipe 72a, and a nozzle 75 is attached to a tip of the bypass pipe 74. A shutter 76 that opens and closes the lens surface of the measurement sensor 16B is disposed downstream of the nozzle 75, and is configured so that the shutter 76 closes by the force of air (for example, 5 kg / cm ² ) injected from the nozzle 75. I have. Shutter 7
Numeral 6 is made of, for example, a spring rope.
It is in an open state at the border. Therefore, at the time of pressurization during spot welding, a part of the pressurizing air is guided to the nozzle 75 via the bypass pipe 74 and is jetted from here to the shutter 76, and the shutter 76 is pressed by the force. It becomes a closed state (the state shown by the dashed line in FIG. 10). When the pressurization is completed, the injection of air from the nozzle 75 stops, and the shutter 76 returns to its original open state due to its own stress (the state indicated by the solid line in FIG. 10).

According to this mechanism, wiring can be reduced. In addition, since a part of the air jetted from the nozzle 75 is blown to the lens surface of the measurement sensor 16B, an effect of cleaning the lens surface can be expected.

Regarding technical problem 5, the statistical processing method is improved. For example, as shown in FIG. 7, the microcomputer automatically performs statistical processing of measured data at the end of each production shift to create a statistical file. The statistics file contains shifts,
The number of measurements, the average value, and the 3σ value for each vehicle type and each part are stored. If the statistical file is used in performing statistical processing for a long section offline (for example, statistical processing for one month), no memory is consumed, and the processing speed is significantly improved. This will be specifically described by comparing the data amounts of the two. For example, if the number of measured vehicles is 400 / shift, the number of vehicle types is 4 and the number of parts is 12, then data for one month (20 days) is processed. In the case of measurement data, 400 vehicles × 12 Parts × 20 days = 96,000 records In the case of statistical data, 4 car models × 12 parts × 20 days = 960 records, and the data processing number is 1/100. Since the processing time is proportional to the number of records processed, the processing time is also 1 /
It is reduced to about 10. Further, in this embodiment, the processing contents are also limited in function, and have a compact configuration including only the time-series transition graph and the histogram.

Regarding the technical problem 6, standardization of the measurement control system on all lines is being attempted. That is, when planning a new vehicle, measurement and control systems will be equipped as standard on the controllers of all major lines in advance. Thus, when measurement is desired, the entire system can be constructed only by introducing the sensor 16 and the personal computer 17 into the process and changing the teaching of the robot 15 and the welding device 30.

As described above, according to the present embodiment, the measurement sensor 16
Can be measured in the welding process by attaching it to the welding robot 15, eliminating the need for a conventional dedicated measurement process, greatly reducing costs and space, and ensuring quality assurance for each process. Self-process assurance becomes possible. In addition, since the body can be measured for each process, information on the change in accuracy between processes becomes clear, and quality analysis becomes easy. Further, since it becomes possible to measure the shape of the work before and after welding in one process, it is possible to grasp the influence of the spot hitting point on the body accuracy. In addition, since the origin post 20 is provided and the origin is measured to calculate the correction value of the measurement position, it is possible to always cope with the accuracy change due to the temperature and the measurement accuracy is guaranteed. Further, since the data processing system can be constructed on an inexpensive personal computer, the cost can be reduced from this point as well.

[0036]

As described above, according to the present invention, the measurement sensor is attached to the welding robot so that the measurement can be performed in the welding process, so that the cost can be reduced.
Self-process guarantee for each process becomes possible, quality analysis based on change in accuracy between processes becomes easy, and the influence on welding accuracy can be grasped from measurement data before and after welding. In addition, since the origin member is provided and the origin value is measured to calculate the correction value of the measurement position, the measurement accuracy is guaranteed even if the measurement is performed in the welding process.

Further, by adopting a configuration in which the measurement sensors are connected to the data processing means via the interface board, it is possible to easily cope with a change in the number and types of the measurement sensors, and to generalize the data processing system. It is planned.

Further, by providing a shutter for protecting the measurement sensor and driving the shutter to open and close by a motor or a fluid pressure cylinder, the measurement sensor can be protected from spatter during welding.

When a configuration utilizing a magnetic field generated at the time of welding as a power source of the shutter is adopted, in addition to protection of the measurement sensor, wiring and piping can be reduced, and further energy saving can be achieved.

In the case where a structure using pressurized air as a power source of the shutter is employed, in addition to protection of the measurement sensor, wiring saving and cleaning effect of the lens surface of the measurement sensor by blowing air can be obtained. It is planned.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a simplified vehicle measuring device of the present invention.

FIG. 2 is a configuration diagram of a data processing system.

FIG. 3 is a diagram for explaining a data structure;

FIG. 4 is a diagram for explaining an origin post measuring method.

FIG. 5 is a flowchart of a measurement position correction process.

FIG. 6 is a structural diagram of a sensor with a shutter.

FIG. 7 is a schematic configuration diagram showing another embodiment of the sensor protection function.

8 is a detailed view of a portion A in FIG. 7;

FIG. 9 is a detailed view of a portion C in FIG. 7;

FIG. 10 is a schematic configuration diagram showing still another embodiment of the sensor protection function.

FIG. 11 is a diagram for explaining a statistical data processing method;

FIG. 12 is a configuration diagram of a conventional vehicle body measurement system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Assembly body 15 ... Welding robot 16, 16A, 16B ... Measurement sensor 17 ... Personal computer (data processing means, 1st correction means, 2nd
Correction unit) 18 Robot control panel (control unit) 19 Line control panel (control unit) 20 Origin post (origin member) 21 Welding gun 36, 58, 76 Shutter 37 Motor 52 Coil 54 Electromagnet 57 ... Movable piece 56 ... Spring (spring member) 56A ... leaf spring (spring member) 70 ... Pressure cylinder 75 ... Nozzle

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-11815 (JP, A) JP-A-63-299884 (JP, A) JP-A-62-259107 (JP, A) JP-A-61-259107 140807 (JP, A) JP-A-1-207610 (JP, A) JP-A-2-38913 (JP, A) JP-A 62-35340 (JP, U) JP-B 54-3647 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 9/12 B25J 9/10 G05D 3/12

Claims (6)

(57) [Claims] 1. A a measurement sensor attached to the welding robot welding gun is attached, and data processing means for processing the output data of the measuring sensor, in order to assure the body measurement accuracy of the measuring sensor
A fixed origin member, first correction means for calculating position correction data by comparing data obtained by measuring the origin member with initial data, and correcting a body measurement position by the measurement sensor based on the position correction data. And a control means for controlling the welding robot so that the measurement sensor comes to a predetermined body measurement position. 2. The simplified vehicle body measuring device according to claim 1, wherein the measurement sensor is connected to the data processing means via an interface board to which a plurality of sensors of the same type can be connected. 3. The simplified vehicle body measuring device according to claim 1, further comprising: a shutter that can be opened and closed to protect the lens surface of the measurement sensor; and a motor that drives the shutter to open and close. 4. The simplified vehicle body measuring device according to claim 1, further comprising: a shutter that can be opened and closed to protect a lens surface of the measurement sensor; and a fluid pressure cylinder that drives the shutter to open and close. 5. An openable and closable shutter for protecting a lens surface of a measurement sensor, a coil for converting a change in a magnetic field generated at the time of welding into an electric current, an electromagnet connected to the coil, The movable body measuring device according to claim 1, further comprising: a movable piece facing the electromagnet via a spring member. 6. An openable and closable shutter for protecting a lens surface of a measurement sensor, and a nozzle for injecting pressurized air supplied to a pressurizing cylinder of a welding gun toward the shutter. The simple vehicle measuring device according to claim 1, wherein