JPS63114853A - Automatic processing device with sensor - Google Patents

Abstract

PURPOSE:To improve copying accuracy and enable the inform execution of route control at all times by specifying the shift route of a processing tool between two sensing points via an operation and making positional control for the tool in a shorter frequency than detected through a plurality of shift target points provided in the route. CONSTITUTION:When a welding torch 3 has reached a sensing point P1, a robot control device 9 reads the positional data P2 of the next sensing point from FIFO device 8, and specifies the shift route L12 of the welding torch 3 between sensing points P1 and P4 on the basis of a predetermined linear interpolation formula, as shift route interpolation information is LNR. Then, the shift route L12 is divided into N shift target points and when the target points have been set up, an operation is made about a divided route for the motion of the welding torch 3 at every control frequency T0. And a position vector resulting from a shift vector added to the present position P=P1 is outputted to an arm joint angle conversion device 10 as the next shift target point. When the welding torch 3 has reached the sensing point P2 as aforementioned, the next welding line position data P3 are read from a device 8 and a similar operation is executed, thereby repeating the aforementioned process.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to automatic processing 'AX' represented by welding robots,
In particular, the present invention relates to an automatic machining device that automatically traces machining lines using a sensor.

[Conventional technology]

Conventionally, this type of automatic processing device has been described in the document “Visu
ally Guided Arc-Welding R
robot With Self-Training
Features J (TECNICAL P
APER, 1983, 5ociety of Man
There is one described in Ufactoring Engineers). FIG. 5+al is a block diagram showing a control device for a welding robot disclosed in the document,
1 is a robot, 2 is a torch holder attached to the arm of the robot 1, 3 is a welding torch which is a processing tool, 4 is a wire, 5 is a visual sensor (such as a CCD camera) for detecting the welding line position, and the torch holder 2 It is rotatably supported by the welding torch 3 and always precedes the welding torch 3. In addition to the visual sensor 5, the welding line position detector includes, as shown in FIG. 6(a),
A laser projector 5A is provided, and the laser projector 5A projects a slit light onto a welding line WL which is a processing line of the workpiece W, and the visual sensor 5 images the light cutting line created by the slit light O5. FIG. 6 (bl shows the imaging screen of the visual sensor 5. 6 is an image processing device, and the visual sensor 5
A video signal sent out by the controller is taken in at a certain sampling period and image-processed to detect a point ps <xs, Ys) (bending point position in FIG. 6(b)) on the welding vAWL on the imaging plane (two-dimensional). 7 is a coordinate conversion device that converts position data Ps (Xs, Ys) of the welding %'iWL output point (the above-mentioned curved black sintering W) sent by the image processing value W6 on the robot coordinate system (three-dimensional). Position data p”s<xs, Y
s, Zs). 8 is a first-in, first-out storage device (
The robot control device 9 sequentially accumulates the detection point position data P1 sent by the coordinate conversion device 7 at each detection cycle, and sequentially reproduces the first stored detection point position data. Send to. The robot control device 9 sequentially reads out the detection point position data P9 from the FIFO device 8 in accordance with the stored control algorithm and calculates the next target point. Reference numeral 10 denotes a joint angle conversion device that converts the target point calculated by the robot control device 9 into a joint angle vector θ of the welding robot 1 and sends joint angle commands θ, to θ6 to the welding robot 1. 11 is a model memory. The welding robot 1 is a six-axis robot, and the sixth axis is used to rotate the visual sensor 5 about the torch axis.

In this device, first, without welding, the visual sensor 5 traces the welding start point to the welding end point, and the detected points in between are sequentially stored in the model memory 11, and the welding line WL is automatically taught. (Training mode). The position data stored in the model memory 11 is the welding start point P during welding.
In order to calculate 1°, the visual sensor 5 also detects the welding line WL.
is used to control the rotation angle (sixth axis) of the visual sensor 5 so as to capture the image within its field of view.

The visual sensor 5 moves ahead of the welding torch 3 while being controlled to capture the welding line WL within its field of view as described above, and the point on the welding line WL sent out by the visual sensor 5 is detected at a certain detection period. Welding line position data P′″ on the robot coordinate system
are detected and sequentially stored in the FIFO device 8. When point L on welding line WL is detected as described above, F
Detection point position data P9n stored in IFO device 8
The detection point position data stored first among the above, for example,
p+ is read into the robot control device 9, the next target point is determined, and joint angle commands (θ1 to θb) are supplied to the welding robot 1.

[Problem that the invention seeks to solve]

In this way, in the conventional method described above, the detection line position data P''
At each detection cycle, the first stored detection point position data is read out, the next target point is determined, and the joint angle command (θ, ~ θ6
) is given to the welding robot 1, so when the welding torch 3 moves between adjacent detection points, that is, between P"I'l-1 and P"0, the movement trajectory is optimal. There is no guarantee that the travel path will be straight or curved, for example. For this reason, when the welding speed becomes high as in the case of thin plate welding, the distance between the detection points increases, so the deviation (error) between the actual welding line WL and the movement trajectory of the welding torch 3 increases. growing. In addition, the detection cycle is irregular because the processing speed of the image processing device changes depending on various conditions, such as the presence or absence of noise, and in the conventional system described above, the robot control cycle depends on the irregular detection cycle. Therefore, joint angle trajectory control is not performed regularly, and in order to keep the detection cycle constant and control joint angles uniformly on all buses, it is necessary to
There was a problem in that the overall hardware and software had to become complicated and expensive.

This invention was made to solve the above problem.
The tracing accuracy of the processing tool can be improved compared to the conventional method without complication and without causing a significant increase in price, and the path control of the processing tool can always be performed uniformly. The purpose is to obtain an automatic processing device with a sensor.

[Means to solve the problem]

In order to achieve the above object, the present invention specifies the processing tool movement path between two adjacent detection points by calculation, sets a plurality of movement target points on the path, and sets a predetermined control period shorter than the detection period. The processing tool is positioned to be controlled at the movement target point.

[Effect]

In this invention, the processing tool moves along a specified movement path and is controlled to move to a movement target point set on the movement path in a control period shorter than the detection period. By simply adding an algorithm, it is possible to significantly improve the tracing accuracy of processing tools compared to conventional methods.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

A case will be described in which the present invention is applied to the welding robot device shown in FIG. 5(a).

FIG. 1(a) shows detection points P1, P2, P3...P,...P7 on the welding line WL captured by the visual sensor 5, and these detection points are Position data on the robot coordinate system (for convenience of explanation, subscript (*)
), P+, Pz, P,...P,...PI
, F as explained in FIG. 5(a).
The information is stored in the IFO device 8 as shown in FIG. 1 (1). At the time of this storage, moving route interpolation information (designated at the time of the above-mentioned teaching), LNR (straight line) or CIR (curve) is added. It is now assumed that the welding torch 3 has just arrived at the detection point P1, and this time is designated as it, and the welding torch 3
Let the moving speed of be v (mm/sec). When the welding torch 3 arrives at the detection point P1, the robot control device 9 reads the position data P2 of the next detection point from the FIFO device 8, and since the moving route interpolation information is LNR, the Movement path LI of welding torch 3
2 is specified as shown in FIG. 1(C) based on a predetermined linear interpolation formula.

■When the above moving route L+z is specified, the moving route L1
□ as shown in Figure 1 (C1)
Divide into N moving target points. The coordinates of each dividing point are pl
, pg, ps, . . . pN. The number of divisions N is determined by the control period of the robot 1 (T0 = constant), the moving speed V of the welding torch 3, and the distance of the moving path L I 2. Note that this control period T0 is a value smaller than the minimum value of the detection period, for example, if this detection period is 200 m
If it is s, set it to about 20m5.

■ Movement target point p+, pg, ps on movement route L1□
... ps (, =P) is completed, the next divided path (hereinafter referred to as movement vector) Δβ (Δx1Δy, Δ2) (=
constant), that is, the movement vector Δ! =P1 °pI to pl
'l) 2%p2 °p3"'5ps-+-pN is calculated. ■When the above movement vector Δ! is calculated, the current position P
= P, to the position vector that is the sum of the movement vector Δβ =
p+Δjl! Joint angle conversion device 1 as the next movement target point
Send to 0. The joint angle conversion device 10 converts the position vector into a joint angle vector θ using a joint angle conversion matrix M(Dz).

(2) In this way, when the welding torch 3 arrives at the detection point P2, the next welding line position data P3 is read from the FIFO device 8, and the calculations (1) to (4) above are executed. After this, this operation is repeated.

FIG. 2 shows the calculation algorithm for the linear interpolation. Between the cores, the current position of the welding torch 3 is indicated by P, and the movement target point is indicated by Pi.

Next, the case of the above-mentioned linear interpolation will be specifically explained with reference to FIG. Now, the distance between 21 and 22: 10m, the setting speed of welding toe 3: 50mm/sec, robot control law'
MTo: Suppose that it is 20 ms ec.

The robot joint angles are controlled according to the joint angle vector θ every control cycle. Since the set speed V is 50 mm/Sec, the distance the robot should move in one control period is 1 mm. Now, the distance between 21 and 22 is 10 m, and the number of times of control (how many times control is performed using the joint angle vector θ) in this section, that is, N is N=10.

Once the division number N is determined, the movement vector Δ°C to be moved in one control period is calculated based on the following formula.

Pz P+ Δβ−□ ・・・・・・(11 (Equation 11 is calculated only when starting from detection point P1. Next,
P i =P, +Δβ−・・・・・・・・・・(2)
is calculated, Pi is converted to joint angle vector T by joint angle matrix M, and θ=M(Pi) ・ ・ ・ ・ ・ ・ ・ ・
・ ・ ・(3) The welding robot 1 is controlled by this θ. Thereafter, in every control cycle, P=P i, that is, until the welding torch 3 reaches the target value WPi from the current position P,
The following process is repeated.

Pi=P+Δl, θ≠M(Pi) (4) In this embodiment, the control period T is 200 ms for the detection period.
Since 0 is 20ms e c, the detection period is 10 times finer than the conventional case where the detection period is the robot control period. 11 can be performed, and that's all, the movement path of the welding torch 3 and the welding 45! Reduce the deviation from WL (
can do.

Next, a case will be described in which curve interpolation is performed between detection points using a curve as shown in FIG. 3 (al), for example, an arcuate curve C. FIG.
Further, FIG. 4 shows the calculation algorithm.

When performing this curve interpolation, unlike linear interpolation,
The movement vector Δβ described above is not constant but variable. When the welding torch 3 arrives at the detection point P, the number of position data that can specify the curve C, in this example, the position data P
2 and P3 are read from the FIFO device 8, and the movement vector Δ to be moved every control cycle between the movement path curves P and P is calculated.
Calculate Ai (i=l, 2.3,...) = 1 Δ to 1° After that, the moving target point Pi is calculated as in the case of linear interpolation, and Pt is the joint angle vector by the joint angle matrix M. This is converted into θ, and the welding robot 1 is controlled by this θ.

In the above embodiments, a welding robot device has been described, but the present invention can be applied to other automatic processing devices such as an automatic sealing device to obtain similar effects.

〔Effect of the invention〕

As explained above, this invention makes it possible to control the path of the processing tool at fine pitches by making the control period smaller than the detection period of the cutting line, thereby improving the tracing accuracy of the processing tool compared to conventional methods. In addition, the control period can be made independent of the detection period, so the path control can be always performed uniformly, and the hardware and software of the detection section can be constructed easily. Since there is no need to take the control period into consideration in some cases, there is an advantage that the device can be simplified and costs can be reduced.

[Brief explanation of the drawing]

Figure 1 (al is a diagram of the relationship between the welding torch, visual sensor, and detection points for explaining the operation of the embodiment of this invention, and Figure 1 (bl is for explaining the contents of the FIF○ device in the above embodiment) Figure 1 (fc) is a diagram showing the interpolation straight line and moving target point in the above embodiment, Figure 2 is a diagram showing the calculation algorithm in the above embodiment, and Figure 3 (a) is a diagram showing another embodiment of the present invention. A diagram showing an interpolation curve and a movement vector for explaining the operation of the example, FIG. 3(b) is a diagram for explaining the contents of the FIFO device in the other embodiment, and FIG. 4 is a diagram for explaining the other embodiment described above. A diagram showing the calculation algorithm in an example, Fig. 5 (al is a block diagram showing a conventional device, Fig. 5)
is a diagram for explaining the operation of the above conventional example, and FIG. 6 (al.
is a diagram for explaining welding line position detection using the optical cutting line method; FIG. 6 (bl is a diagram showing an image of a visual sensor); Sensor, 6--Image processing device, 7--Coordinate conversion device,
8--First-in-first-out storage device, 9-muscle robot control device, 10--Joint angle conversion device.

Claims (1)

[Claims] A sensor that is located in a position preceding the processing tool and detects the processing line, a device that captures the output of the sensor at a certain period to create detection point position data, and a pre-input device that accumulates the detection point position data from the device. In an automatic processing device with a sensor, the sensor-equipped automatic processing device is equipped with a storage device of a first-output method, and a control device that sequentially reads out the detection point position data from the storage device and controls the processing tool to a target point given by the detection point position data. The device specifies the processing tool movement path between the two adjacent detection points by calculation, sets a plurality of movement target points on the path, and moves to the movement target point in a predetermined control cycle shorter than the above period. An automatic processing device with a sensor that controls the position of processing tools.