JPS59226909A - Positioning method of automotive robot - Google Patents

Abstract

PURPOSE:To improve positioning precision by measuring the current position of a robot automatically, calculating the deviation from a target position, and correcting the position of the robot itself automatically on the basis of the deviation. CONSTITUTION:The robot which is stationary is driven, and the distances from a turntable 7 to two points on an object of operation are detected to calculate the angle of inclination of the table 7 to the object of operation and the amount of eccentricity from the table 7 to a normal reference track that the robot runs on from said distance data. Then, an outrigger device 10 is extended to elevate a truck 1 from the ground, the truck 1 is rotated at right angles to the object of operation; and the device 10 is contracted to place the truck 1 on the ground, and then the table is rotated until the table becomes parallel to the object of operation. Further, the truck is moved by the extent of eccentricity to align its center to the reference track. Then, the device 10 is extended to hold the truck 1 above the ground, and rotated to in parallel to the object of operation, and the device 10 is contracted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for positioning an industrial robot that can travel on a trolley, and more particularly to a method for automatically positioning an industrial robot with respect to a work object.

Among robots for spraying heat-resistant materials (e.g. rock wool), cement, etc., robots for painting, etc., industrial robots that can move on their own using a traveling trolley are positioned relative to work targets such as walls and beams. In such cases, a conventional method of positioning by radio guidance is generally used, using a guidance wire laid on the ground or floor (hereinafter referred to as "floor") as a guide.

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 induction wires on the floor, which increases costs.

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 positioning methods are not sufficient.

Therefore, an object of the present invention is to improve the positioning accuracy of an industrial robot that runs with its own blade on a traveling cart, and in particular, to automatically measure the current position of the robot and calculate the deviation from the target position. The purpose of the present invention is to provide a positioning method that can exhibit an automatic position correction function that automatically corrects the position of the robot itself based on this. A method for positioning a self-propelled robot with respect to a work object, in which a rotating table having a vertical outrigger device is attached to the rotating table, and an arm mechanism having multiple degrees of freedom is installed on the rotating table. The process of detecting the distance from the rotating table to two measurement points on the workpiece by using a step of calculating the eccentricity l to the normal reference trajectory; a step of extending the outrigger device to ground the cart, and then rotating the cart in a direction perpendicular to the workpiece; After oriented at right angles to the workpiece, the outrigger device is retracted to ground the cart, and the turning table is rotated until it is parallel to the workpiece. a step in which the outrigger device is extended and the cart is grounded, then the cart is rotated until it is parallel to the object to be worked on, and the outrigger device is further retracted. A method for positioning a self-propelled robot is provided. Next, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

FIG. 1 is a front view of a rock wool spraying robot to which the present invention can be applied, FIGS. 2 and 3 are a plan view and a side view of the industrial robot, and FIG. 4 is a diagram of the industrial robot. The control circuit diagram, Fig. 5 is a flowchart showing the control procedure, Fig. 6 is a plan view showing the movement state of the cart and the turning table, and Fig. 7 shows the state of inclination and displacement of the robot robot 1~ with respect to the work object. FIG.

In FIGS. 1 to 3, a trolley l has four wheels 2 rotatably at its lower part, and one or two driving wheels 2a of these wheels are connected to a traveling motor 4 by a chain 3. The rotation of the travel motor 4 causes the truck 1 to travel in the direction of the axis 5 of the truck 1 shown in FIG.

The truck 1 is connected to a substantially flat turning table 7 via a turning hair ring 6 provided on its upper surface. This rotating table 7 is rotatable.
is driven to rotate in a horizontal plane relative to the trolley 1 by a rotation motor 9 fixed on a rotation table 7.

Pulse encoders PE and PE2 are connected to the travel motor 4 and the swing motor 9, respectively, and the rotation angle of each motor is detected.

The above-mentioned turning table 7 has an outrigger device 1o that can be expanded and contracted in the vertical direction at its four corners. It is detected by the potentiometer PM.

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.
A horizontal arm 13 is attached which is driven to swing in the same swing plane as the horizontal arm 13, and a potentiometer PM for position detection is attached to the tip of the horizontal arm 13 via a wrist portion 14 having multiple degrees of freedom. It is being Incidentally, the swing angles of the vertical arm 12 and horizontal arm 13 are detected by an arm drive motor M that drives each arm, and pulse encoders PEa and PEI attached to M.

An example of the control circuit of the spraying robot configured as described above is as shown in FIG.
output lines A, C, and output lines E, D of PEa, PEI,
Furthermore, the output line B of the potentiometer PMI and the potentiometer PM2 are each connected to an input interface circuit 16 constituting the microcomputer 15.

The microcomputer 15 can be a well-known one, and includes the input interface circuit 16 that inputs signals from various detectors, and a read-only memory ROM, 1 that inputs signals from the input interface circuit 16.
7, and store various data in the temporary storage circuit RAM 18 as necessary.
It is also comprised of a CPU (Central Processing Unit) 20, etc., which sends output signals to an output interface circuit 19 connected to various drive devices, display devices, etc., while the output interface circuit 19 includes the swing motor 9, the travel Motor 4, upper motor 1 for driving outrigger device
0m and motors Ma and Mto for driving each arm are connected 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 from the output interface circuit 19 is as follows.
After being converted into an analog quantity by the D/A converter 21,
The rotation angle of the travel motor 9 is transmitted to the comparator 23 via the amplifier 22 and then to the travel motor 9, and the rotation angle of the travel motor 9 is detected by the pulse encoder PR. The pulse encoder PE rotates the swing motor 9 in a direction in which the difference between the detected amount and the target position signal becomes 0, and the rotational position of the cart 10 relative to the swing table 7 is determined.

In the teaching state, the detected amount of the pulse encoder PE emitted from the J-recorded D/A converter 24 is transmitted to the CPU 20 via the input interface circuit 16 and stored in the RAM 1B as teaching position data.

Next, the procedure for positioning the spraying robot 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, as shown in a and b in FIG.

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 cart 1 is traveling in step a.

The travel distance of the trolley l is detected by the pulse encoder PE, and the pulse encoder PE determines whether the rano output value has reached a value corresponding to the set working position or not in step b.
If it is determined that the work position has not been reached, return to step a and continue traveling, and if it is determined that the working position has been reached, the traveling motor 4 is stopped in step C to stop the trolley 1.

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 represented by 0. Now, the axis 5 in the direction of the wheel 2 of the truck 1 is parallel to the steel beam 25 and is inclined at an angle of 0 with respect to a line 26 passing through the center 0, and also passes through the center 0 of the truck 1. line segment 2
6 is located at a position shifted by a distance β from the reference locus 27 indicating the locus position where the trolley l 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 truck 1 and the turning table 7 are rotated counterclockwise around point 0, so that the axis 5 of the truck is arranged parallel to the steel beam 25, and the center point 0
By moving the trolley 1 and turning table 7 in the direction of the steel beam 25 for 40 minutes, and positioning the trolley 1 and the turning table 7 at a position parallel to the steel beam 25 and a designed distance (L) away from the steel beam 25, 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,
Next, the CPU connects the outrigger drive motor 10m to the input interface circuit 19, D/A converter 28, and amplifier 2.
9. Send out a positive direction signal, ie, a signal in the direction in which the outrigger device 10 extends, via the comparator 30. The extension and opening of the outrigger device 10 is controlled by the potentiometer PM 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 1o is at a distance d from the original floor surface 11.
, so all wheels 2 of trolley 1 are on the floor 11
When the rotating table 7 is lifted from the ground and separated from the floor (step d), and the rotating table 7 is fixed on the floor 11 by the four outrigger devices 1o, the rotating motor for rotating the rotating table 7 is activated. 9, a motor MaMl that drives the vertical arm 12, and the horizontal arm 13;
The wrist part 1 is attached to the tip of the horizontal arm 13 by driving the
4 in the direction of the steel beam 25, and a potentiometer PM, which is a type of position detector, is attached to the wrist portion 14;
The tip of is pressed against the steel beam 25, and the distance from the axis 5 of the trolley 1 to the steel beam 25 is set at two positions P, which are separated by the same distance (W/2) left and right in the direction from the center 0 to the axis 5. and P2
Measure about. The distance W (constant) between the above points p and P2 in the direction of the axis 5, and the axis ○ between each measurement point P and P2.
The measurement distance to ℃1 and! 2 (see Figure 7).

Distance like 111-,,l! , + and p2 measurements are:
Rotation angle α+ corresponding to each length of the horizontal arm 13 and vertical arm 12 and each measurement point PI and P2 of the rotation table 7
α2 (these are detected by the pulse encoder PE2), the swing angle β of the vertical arm 12, and the swing angle T of the horizontal arm 13 (each shown in FIG. 1 and attached to each joint). PE□ and PEI
, which is detected using , ) is obtained 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, in step e, the turning table 7 and each arm 12.13 are swung, and in step f, the distance j2.
, N2, in the next step g, the extension of the steel beam 25 of the bogie 1 is calculated using the equation θ=jan-' (ΔA/W) 1-(ff, +#,)/2-L. The angle θ and the distance l, that is, the amount of displacement of the current center point O from the reference locus 27 are calculated.

Here, Δρ is the difference between the distances i and C, and is calculated by considering the positive and negative signs. Note that the error in the above formula increases as the value of θ increases, but since θ is usually not a very large value, the above formula may be used.

However, it is 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 e from the reference trajectory 27 in step g, the direction of the potentiometer PM2 is then changed by bending the wrist portion 14, oscillating the arms, and then rotating the direction of the potentiometer PM2. By rotating the table 7, the measurement points P and P are changed in the vertical direction.
Measure the height of the steel beam 25 at a point Po between 2 and
Measure the deviation Δh from the reference height. As a result, the amount of deflection of the steel beam 25 is detected. (Step h) Then the CPU
20 sends a drive signal to the swing motor 9 to rotate the cart 1 counterclockwise by θ+90 degrees with respect to the swing table 7. This rotation causes the axis 5 of the truck 1 to be oriented perpendicularly to the steel beam 25. (Step i) After completing the determination of the direction of the truck in this way, in step j, a drive signal is sent to the outrigger drive motor 10m in the direction in which the outrigger device 10 is retracted, and the car of the truck 1 is moved! Ground fa2. As a result, the outrigger device 10
Since the rotation table 7 is cut off from the ground, a drive signal is sent to the rotation morph 9 again in the following step k, and the rotation table 7 is rotated at an angle θ.
rotate counterclockwise relative to the trolley l by the amount of time.

The above procedure brings the turning table 7 into a state parallel to the steel beam 25.

Subsequently, the CPU 20 sends a drive signal to the travel motor 4,
The truck 1 is moved by 4 along with the rotating table 7 and arms 12 and 13 on top of it.

At this point, all of the wheels 2 are facing in the same direction as the axis 5, that is, in a direction perpendicular to the steel beam 25, so the truck 1 approaches the steel beam 25 by a distance l by the 4-minute movement described above. Otherwise, the center 0 of the truck 1 moves onto the reference trajectory 27. (Step m) Next, the CPU 20 sends a signal in the extension direction to the outrigger driving motor 10m, extends the outrigger device 10, and turns the wheels 2 of the truck 1 off.
Step n), the drive signal is sent to the turning motor 9 again to turn the grounded truck 1 90 degrees clockwise (Step 0), and then the outrigger device 10 is retracted (Step p
), the wheels 2 are grounded on the floor 11, and the outrigger equipment fio
float in the air.

In this way, the cart 1 and the turning table 7 are both parallel to the steel beam 25, and the center 0 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, it becomes possible to carry out teaching operations to teach the robot the exact position of the steel beam 25 with respect to the reference trajectory 27, and regeneration work using the spray gun attached to the tip of the wrist 14 instead of the potentiometer PM2. The procedure shown in FIG. 5 above is just one example of the use of a spray robot according to an application example of the present invention. , for example, concrete spraying robots and painting robots 7
It can be used for a variety of purposes, such as a gutter, an inspection port for long objects, and an IC gutter, and various variations can be considered, such as changing the order of the work procedure as appropriate or adding and inserting another work procedure. , for example, distance 7! in step e!
After calculating the angle θ around 1 by detecting 1 and β2, the cart is rotated by θ plus 90 degrees, and the steel beam 25
, and rotate the turning table 7 by an angle θ. While keeping the turning table 7 perpendicular to the steel beam 25, measure the distance to one measurement point PO on the steel beam 25 again and find e. All changes such as removing the influence of the inclination angle θ on the calculation of β by detecting the angle θ correspond to the embodiments of the present invention.

Further, the deflection amount 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 for adjusting the height direction position of the spray gun, etc.

As described above, the present invention is a self-propelled robot in which a rotating table having a vertical outrigger device is attached to a cart that travels on the floor with wheels, and an arm mechanism having multiple degrees of freedom is installed on the rotating table. In this positioning method for a workpiece, the robot stopped at the work position is driven to detect the distance from the rotation table to two measurement points on the workpiece, and the rotation table is detected from the two distance data. The inclination angle θ with respect to the workpiece is
and the process of calculating the eccentricity β from the turning table to the regular reference trajectory that the robot should travel, and after extending the outrigger device and cutting the trolley off the ground, the trolley is rotated in a direction perpendicular to the workpiece. and a step of orienting the cart perpendicularly to the workpiece, retracting the outrigger device to ground the cart, and then rotating the turning table until it is parallel to the workpiece. , the process of moving the trolley by an eccentric amount of 4 minutes and aligning its center with the regular reference trajectory, and the step of extending the outrigger device to cut the trolley off the ground, and then rotating the trolley until it is parallel to the object to be worked on. This positioning method for a self-propelled robot is characterized by the steps of: , and further retracting the outrigger device, so the positioning accuracy is significantly improved compared to the conventional positioning method for a traveling robot using guided radio. In addition, there is no need to lay guide rails, etc., or the trouble of changing the position of the guide rails, etc. every time the position of the work object changes, and the work object can be positioned quickly in response to changes in the position of the work object. The present invention provides an industrial robot, and is extremely suitable for use in industrial robots that require precision, such as in rock wool spraying operations.

[Brief explanation of the drawing]

Fig. 1 is a front view of a rock wool spraying robot to which the present invention can be applied, Figs. 2 and 3 are a plan view and a side view of the industrial robot, and Fig. 4 is a control circuit of the industrial robot. Figure 5 is a flowchart showing the same control procedure, and Figure 6 is a flowchart showing the same control procedure.
The figure is a plan view showing the state of movement of the cart and the turning table, and FIG. 7 is a plan view showing the state of inclination and displacement of the robot I with respect to the work object. (Explanation of symbols) ■...Dolly 2...Wheels 4...Travel motor 5...Axis 6...Swivel bearing 7.
...Swivel table 9...Swivel motor 10...Outrigger device 12...Vertical arm 13...Horizontal arm 14...Wrist portion 15...Microcomputer 20...CPU θ...Inclination Angle P...
P2...Measurement point. PM... Potentiometer PE... Pulse encoder. Applicant Kobe Steel Co., Ltd. Representative Patent Attorney Takeo Honjo Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] Operation of a self-propelled robot in which a rotating table having a vertical outrigger device is attached to a cart that travels on the floor with wheels, and an arm mechanism having multiple degrees of freedom is installed on the rotating table. A method for positioning a workpiece includes: (i) driving a robot stopped at a work position to detect the distance from a rotating table to two measurement points on the workpiece; and (ii) measuring the two distances. A process of calculating from the data the inclination angle θ of the turning table with respect to the workpiece and the eccentricity β from the turning table to the normal reference trajectory on which the robot should travel; (iii) extending the outrigger device to ground the cart; After that, the cart is rotated in a direction perpendicular to the workpiece, and after the steps (iv) and (iii), the outrigger device is retracted to ground the cart, and the rotating table is rotated against the workpiece. (v)
The process of moving the trolley by an eccentric amount of 4 minutes and aligning its center with the regular reference trajectory; (vi) After extending the outrigger device and cutting the trolley off the ground, until the trolley is parallel to the workpiece. A method for positioning a self-propelled robot, comprising the steps of rotating and further retracting an outrigger device.