JPH0379156B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot that can travel on a trolley, and more particularly to an industrial robot that can automatically position itself relative to a work object.

Among robots for spraying heat-resistant materials (e.g. rock wool) and cement, robots for painting, etc.
When positioning an industrial robot that can move on its own using a traveling trolley with respect to a work target such as a wall or beam, it is guided by guide lines that are conventionally laid on the ground or floor (hereinafter referred to as the floor). A positioning method using guided radio is generally used.

However, in this positioning method using guided radio, the positioning accuracy is poor and it is not possible to make detailed position corrections in response to changes in the position of the workpiece, and there is also no means for correcting accumulated errors. In addition to chipping, it is necessary to lay the induction wire on the floor, which increases cost.

In particular, in modern buildings, fireproofing materials such as rock wool are often sprayed onto steel beams to improve fire resistance, and the spraying robots used to perform these tasks must perform highly precise spraying operations. , traditional guided radio type positioning methods are not sufficient.

Therefore, an object of the present invention is to improve the positioning accuracy of an industrial robot that moves by itself on a traveling cart, and in particular, to automatically measure the robot's current position and determine the deviation from the target position. The purpose of the present invention is to provide an industrial robot that can perform an automatic position correction function that calculates the position of the robot and automatically corrects its own position based on the calculation. a revolving table that is rotatably supported on the transporter about a vertical axis; and a revolving table that is attached to the revolving table and capable of supporting the revolving table and the transporter on the floor so as to be movable up and down. an outrigger device, an arm mechanism provided on the rotating table and having a plurality of degrees of freedom, a position detector attached to the arm mechanism to detect the distance between the robot and the workpiece, and the rotating An angle detector that detects the turning angle of the table with respect to the cart, and control that calculates and corrects the direction and position of the cart and the turning table based on information from the position detector and the angle detector. The present invention provides an industrial robot comprising a device.

Next, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

Here, FIG. 1 is a front view of an industrial robot according to an embodiment in which the present invention is applied to a rock wool spraying robot, FIGS. 2 and 3 are a plan view and a side view of the same industrial robot, and FIG. The figure is a control circuit diagram of the industrial robot, Figure 5 is a flowchart showing the control procedure, Figure 6 is a plan view showing the moving state of the cart and rotating table, and Figure 7 is the inclination of the robot with respect to the work object. FIG.

In FIGS. 1 to 3, a truck 1 has four wheels 2 rotatably at its lower part, and one or two drive wheels 2a of these wheels are connected to a travel motor 4 by a chain 3. The carriages 1 are connected to each other, and the carriage 1 travels in the direction of the axis 5 of the carriage 1 shown in FIG. 2 by the rotation of the travel motor 4.

The truck 1 has a swing bearing 6 provided on its upper surface.
The rotary table 7 is connected to a substantially flat plate-shaped rotary table 7 via the rotary table 7, and the rotary table 7 is rotatable about the vertical axis 8 of the truck 1, which is the center of the rotary bearing 6. 7
The cart 1 is driven to turn in a horizontal plane by a turning motor 9 fixed above.

Pulse encoders PE ₁ and PE ₂ are connected to the traveling motor 4 and the swing motor 9, respectively,
The rotation angle of each motor is detected.

The above-mentioned turning table 7 has an outrigger device 10 that is vertically extendable and retractable at its four corners, and is driven to extend and contract by an outrigger device driving motor _10n on the turning table 7 of this outrigger device 10, and the amount of expansion and contraction is Detected by potentiometer PM ₁ .

The state shown in solid lines in FIGS. 1 and 3 is a state in which the outrigger device 10 is retracted, and when the outrigger device 10 is extended, the swing table 7 and the truck 1 attached to it via the swing bearing 6 move upward. The wheel 2 can be separated from the floor surface 11 (ground cutting).

On the rotating table 7, there is a vertical arm 12 that is swing-driven in a vertical plane including the vertical axis 8, and a vertical arm 12 that is attached to the tip of the vertical arm 12 and swings in the same swing plane as the vertical arm 12. A dynamically driven horizontal arm 13 is attached, and a potentiometer PM ₂ for position detection is attached to the tip of the horizontal arm 13 via a wrist portion 14 having multiple degrees of freedom. The swing angles of the vertical arm 12 and horizontal arm 13 are detected by pulse encoders PE _a and PE _b attached to arm drive motors M _a and M _b that drive each arm.

An example of the _control circuit of _the spraying robot configured as described _above is shown in FIG _.
Output lines E, D, and potentiometer
The output line B of PM ₁ and the potentiometer PM ₂ are each connected to an input interface circuit 16 constituting the microcomputer 15.

The microcomputer 15 can be a well-known one, and the input interface circuit 16 inputs signals from various detectors.
Then, the signals from the input interface circuit 16 are processed in accordance with the program stored in the read-only memory ROM 17, and various data are stored in or retrieved from the temporary storage circuit RAM 18 as needed, and various drive devices and It is composed of a CPU (central processing unit) 20 and the like that sends output signals to an output interface circuit 19 connected to a display device, etc., and the output interface circuit 19
The swing motor 9, the travel motor 4, the outrigger drive motor _10n , and the arm drive motors M _a and M _b are connected to each other via their respective automatic control systems.

Since the automatic control systems for each motor and outrigger device have substantially the same structure, the swing motor 9 will be representatively explained, and the others will be omitted. That is, the target position signal of the turning table 7 sent out from the output interface circuit 19 is converted into an analog quantity by the D/A converter 21, and then transmitted to the comparator 23 via the amplifier 22, and is further transmitted to the turning motor. At the same time, the rotation angle of the swing motor 9 is detected by the pulse encoder PE ₂ , and this detected amount is transmitted to the comparator 23 via the D/A converter 24, and the detected amount by the pulse encoder PE ₂ and the target are The rotation motor 9 is driven to rotate in a direction in which the difference from the position signal becomes 0, and the rotational position of the cart 1 with respect to the rotation table 7 is determined.

In addition, in the teaching state, the detection amount of the pulse encoder PE ₂ emitted from the D/A converter 24 is:
CPU 20 via input interface circuit 16
and stored in the RAM 18 as taught position data.

Next, the positioning procedure of the spraying robot according to the operation program will be explained with reference to the attached drawings starting from FIG.

The following is the procedure for positioning the spraying robot along the steel beam 25.
c... indicates a step number corresponding to each function of the robot. First, a description will be given of the state in which the wheels 2 are driven by the travel motor 4 and the truck 1 is traveling in step a.

The travel distance of the trolley 1 is detected by the pulse encoder PE ₁ , and the output value from the pulse encoder PE ₁ corresponds to a predetermined distance from a preset origin position (start position or previous work position) to the work position. It is determined in step b whether the value has been reached, and if the value has not been reached, the process returns to step a to continue traveling, and if it is determined that the work position has been reached, the travel motor 4 is activated in step c. , and the trolley 1 is stopped.

The trolley 1 in this state is shown by a solid line in FIG. 6, and the turning table 7 placed on top thereof is shown by a chain double-dashed line. Further, the center of the slewing bearing 6, that is, the position of the vertical axis 8 is indicated by O. Now, the axis 5 of the wheel 2 of the truck 1 in the direction (running direction) is at an angle θ with respect to a line 26 that is parallel to the steel beam 25 and passes through the center O.
A line segment 26 that is inclined by an amount of
Let us consider a case where the trolley 1 is located at a position deviated by a distance l from a reference trajectory 27 that indicates a trajectory position where the trolley 1 should originally move parallel to the steel beam 25. In the figure, the direction of the inclination angle θ is clockwise.

In the following work, first the trolley 1 and the turning table 7
By rotating counterclockwise around point O, the axis 5 of the truck is placed parallel to the steel beam 25, and the center point O is moved by l in the direction of the steel beam 25. and a position where the turning table 7 is parallel to the steel beam 25 and a certain design distance L away from the steel beam 25 (on the reference trajectory 27)
This is intended to improve the accuracy of measurement and spraying positions in subsequent teaching and reproducing operations.

When the trolley 1 stops at step c as described above, the CPU then connects the outrigger drive motor _10n to the output interface circuit 19, D/A
A signal in the positive direction, that is, a signal in the direction in which the outrigger device 10 extends, is sent out via the converter 28, amplifier 29, and comparator 30. The amount of extension of the outrigger device 10 is measured by the potentiometer PM ₁ as described above, and the extension work of the outrigger device 10 is stopped at the position where the detected value reaches a predetermined value.
At this time, the outrigger device 10 extends longer than the original distance d from the floor 11, so all the wheels 2 of the truck 1 are lifted up from the floor 11 and separated from the floor (step d), and the truck 1 rotates in this way. The table 7 is connected to the floor 1 by four outrigger devices 10.
a swivel motor 9 and a vertical arm 12 for swiveling the swivel table 7 once fixed on the 1;
Wrist part 1 attached to the tip of horizontal arm 13 by driving motors M _a and M _b that drive horizontal arm 13
4 in the direction of the steel beam 25, and the wrist portion 14
The tip of a potentiometer PM ₂ , which is a type of position detector attached to the Same distance (W/2)
Measurements are taken at two positions P ₁ and P ₂ (measurement points) separated by . Let the distance between the above points P ₁ and P ₂ in the direction of the axis 5 be WW (constant), and let the measurement distances from each measurement point P ₁ and P ₂ to the axis 5 be l ₁ and l ₂ (Fig. 7 reference).

The distances l ₁ and l ₂ as described above are measured using the respective lengths of the horizontal arm 13 and vertical arm 12 and the turning angle α ₁ corresponding to each measuring point P ₁ and P ₂ of the turning table 7.
and α ₂ (these are detected by the pulse encoder PE ₂ ), the swing angle β of the vertical arm 12, and the swing angle γ of the horizontal arm 13 (respectively the pulses shown in FIG. 1 and attached to each joint). encoder
detected using PE _a and PE _b ) by performing a well-known coordinate transformation operation. Since these coordinate transformation procedures are well known, their explanation will be omitted here.

In this way, the turning table 7 and the arms 12, 13 are oscillated in step e, and the distances l ₁ and l ₂ are calculated in step f. Then, in the next step g, θ=tan ^-1 (Δl/W) l= The inclination angle θ and distance l of the truck 1 with respect to the steel beam 25, that is, the amount of displacement of the current center point O from the reference trajectory 27 are calculated using the calculation formula (l ₁ +l ₂ )/2−L.

Here, Δl is the difference between the distances l ₁ and l ₂ and is calculated taking into account the positive and negative signs. Note that the error in the above equation increases as the value of θ increases, but since θ is usually not a very large value, the above equation may be used.

However, although it is also possible to consider the influence of the inclination angle θ, the explanation thereof will be omitted here.

After calculating the inclination angle θ of the trolley 1 and the amount of deviation l from the reference trajectory 27 in step g, the direction of the potentiometer PM ₂ is then changed by bending the wrist portion 14 and oscillating the arms. Furthermore, by turning the turning table 7, the measurement point P 0 is changed vertically, and the point P ₀ between the measurement points P ₁ and P ₂ is changed.
The height of the steel beam 25 at is measured, and the deviation Δh from the reference height is measured. As a result, the steel beam 25
The amount of deflection is detected. (Step h) Next, the CPU 20 sends a drive signal to the swing motor 9, and moves the cart 1 to the swing table 7 by θ+90.
Rotate counterclockwise by degrees. Due to this rotation, the axis 5 of the truck 1 is oriented in a direction perpendicular to the steel beam 25. (Step i) After completing the determination of the direction of the truck, in Step j, the outrigger drive motor 1
_0n , a drive signal is sent in the direction in which the outrigger device 10 contracts, and the wheels 2 of the truck 1 are brought into contact with the ground. As a result, the outrigger device 10 is grounded, so in the subsequent step k, a drive signal is sent to the swing motor 9 again, and the swing table 7 is rotated counterclockwise with respect to the truck 1 by an angle θ.

By the above procedure, the turning table 7 can be moved to the steel beam 2.
It becomes parallel to 5.

Subsequently, the CPU 20 sends a drive signal to the travel motor 4, and moves the cart 1 along with the rotating table 7 and the arms 12, 13, etc., by an amount l. At this point, all the wheels 2 are in the same direction as the axis 5,
In other words, since it faces perpendicular to the steel beam 25,
By the movement of l minutes, the truck 1 approaches or moves away from the steel beam 25 by a distance of l, and the center O of the truck 1 moves onto the reference trajectory 27. (Step m) Next, the CPU 20 controls the outrigger drive motor 1.
0 _n to extend the outrigger device 10 and ground the wheels 2 of the bogie 1 (step n), and then send a drive signal to the swing motor 9 again to move the bogie 1 to the ground. After turning 90 degrees clockwise (step o), the outrigger device 10 is retracted (step p), the wheels 2 are grounded on the floor 11, and the outrigger device 10 is suspended in the air.

In this way, both the cart 1 and the turning table 7 become parallel to the steel beam 25, and the center O is on the reference line 27, completing the complete positioning of the turning table 7 with respect to the steel beam 25. Therefore, in the following step q. As shown, a teaching operation is performed to teach the robot the correct position of the steel beam 25 relative to the reference trajectory 27, and a regeneration operation is performed using a spray gun attached to the tip of the wrist 14 in place of the potentiometer PM ₂ . The procedure shown in FIG. For example, it can be used for various purposes such as concrete spraying robots, painting robots, long object inspection robots, etc., and it can also be used in various variations such as changing the order of the work procedures as appropriate or adding and inserting other work procedures. For example, at step f, the distance l ₁ and
After calculating the inclination angle θ by detecting l ₂ , the cart is rotated by θ plus 90 degrees, and the steel beam 25
The rotation table 7 is held perpendicular to the steel beam 25, the rotation table 7 is rotated by an angle θ, and one measurement point on the steel beam 25 is again held while the rotation table 7 is maintained perpendicular to the steel beam 25.
By measuring the distance to P ₀ and detecting l, the influence of the inclination angle θ on the calculation of l may be removed.

Further, the amount of deflection Δh of the steel beam 25 obtained in step h is stored as is in the RAM 18, and is called out during the subsequent regeneration operation and used to adjust the position of the spray gun, etc. in the height direction.

As described above, the present invention includes a truck having wheels for running on a floor surface, a turning table rotatably supported on the truck about a vertical axis,
an outrigger device attached to the revolving table and capable of supporting the revolving table and the trolley on the floor surface in a freely raised and lowered manner; an arm mechanism provided on the revolving table having a plurality of degrees of freedom; a position detector that is attached to the robot and detects the distance between the robot and the work object; an angle detector that detects the turning angle of the turning table with respect to the cart; and information from the position detector and the angle detector. The industrial robot is characterized by having a control device that calculates and corrects the direction and position of the cart and the revolving table based on The positioning accuracy is significantly improved compared to the positioning method of The present invention provides an industrial robot that can perform positioning in response to changes in the position of the robot, and is extremely suitable for use in industrial robots that require precision in rock wool spraying operations and the like.

[Brief explanation of drawings]

Fig. 1 is a front view of an industrial robot according to an embodiment of the present invention applied to a rock wool spraying robot, Figs. 2 and 3 are a plan view and a side view of the same industrial robot, and Fig. 4 is a The control circuit diagram of the industrial robot; Figure 5 is a flow chart showing the control procedure; Figure 6 is a plan view showing the moving state of the cart and rotating table; Figure 7 is the tilt and displacement of the robot relative to the work object. FIG. (Explanation of symbols), 1...Dolly, 2...Wheel, 4
...Traveling motor, 5... Axis, 6... Swivel bearing, 7... Swivel table, 9... Swivel motor,
PE...Pulse encoder, 10... Outrigger device, PM... Potentiometer, 12... Vertical arm, 13... Horizontal arm, 14... Wrist part,
15...Microcomputer, 20...CPU,
θ...Inclination angle, _P1 , _P2 ...Measurement point.

Claims (1)

[Scope of Claims] 1. (1) A truck having wheels for running on a floor surface; (2) A revolving table rotatably supported on the truck about a vertical axis; and (3) the revolving table. an outrigger device that is attached to a table and capable of supporting the rotating table and the trolley on the floor so as to be able to move up and down; (4) an arm mechanism that is provided on the rotating table and has multiple degrees of freedom; (5) a position detector that is attached to the arm mechanism and detects the distance between the robot and the work target; (6) an angle detector that detects the rotation angle of the rotation table with respect to the cart; (7) the position detection an industrial robot, comprising: a control device that calculates and corrects and controls the direction and position of the truck and the turning table based on information from the robot and the angle detector.