JP2605643B2 - Robot 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 robot apparatus having a trajectory interpolation device mounted on a robot arm.

[0002]

2. Description of the Related Art In the production of automobile body parts and instrumentation parts, a large number of small holes for tightening screws, bolts and nuts, small holes for inserting various parts, polygonal holes, and long holes are formed. There is a need to. This small hole processing is generally performed by press punching. However, in the case of a three-dimensional molded product such as an automobile body part, it is difficult to set a press die, and in addition, a model change of the automobile or The shape and size of the molded product differed depending on the type of vehicle, and it was difficult to apply press punching.

[0003] For this reason, small holes are conventionally processed using a robot. FIG. 16 shows a side view of an apparatus for performing this small hole processing. A multi-degree-of-freedom robot in which a plurality of arms 1a and 1b are connected is used, and a tool 2 is attached to a tip of an arm 1b on the tip side of the robot. For example, a laser gun, a plasma gun, a water jet gun, or the like is used as the tool 2, and a small hole 4 having a predetermined diameter is formed in the three-dimensionally processed work 3 by performing a circular interpolation operation based on a high-speed operation of a controller that controls a robot. Is formed. Similarly, polygonal holes, elongated holes, and the like are formed by combining linear interpolation and circular interpolation.

[0004]

However, in the trajectory interpolation control of a circle and a different shape by a robot, the following to
For this reason, there is a problem that a predetermined hole cannot be formed. Since drilling is non-contact drilling, laser guns and plasma guns are often used as tools, and the peripheral speed of drilling determined by the characteristics of these tools is much higher than the control speed of the robot. Since the diameter of the hole to be machined is small, for example, 4 to 20 mm, it is difficult to perform circular interpolation. In a structure in which a tool is controlled by interpolation processing of different shapes of two axes (XY table) orthogonal to each other, the unit is large, the cost is high, and it is difficult to process cables for a tool, a motor, and the like.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to use a robot whose control speed is slow as compared with the processing speed of a tool for processing a small-diameter circle and a hole having a different shape. It is an object of the present invention to provide a robot apparatus that is small in size and easy to handle cables for supplying energy to a tool.

[0006]

According to one aspect of the present invention, there is provided a robot apparatus including a robot and a trajectory interpolator attached to an arm of the robot. A cylindrical rotary shaft rotatably supported around the axis with respect to the robot arm, and supported at the tip of the rotary shaft so as to be able to rotate and revolve, and at a predetermined distance from the rotation center of the rotary shaft. An operating axis that has a rotation center at a distance, and holds the tool so that the point of action of the tool is located at a position separated by a predetermined distance from the rotation center; and an axis of the rotation axis inside the rotation axis. A cylindrical drive transmission shaft that is rotatably supported around an axis parallel to the center and transmits driving force to the operating shaft, and a cable that passes through the axis of the drive transmission shaft and transmits energy to the tool When,
And the trajectory interpolation device controls the rotation axis and the operation axis independently of the operation of the robot arm to move the tool along the trajectory of the circle and the irregular shape.

[0007]

The robot apparatus according to the present invention includes a robot indicated by reference numeral 6 in FIG. 1 and a trajectory interpolation apparatus indicated by reference numeral 5. Among them, the robot 6 has been proposed and known, so that detailed description thereof will be omitted, and the operation of the trajectory interpolating device 5 will be described after the outline and the principle have been described.

The trajectory interpolating device 5 includes a large number of arms 7a, 7
arm 7b on the tip side of multi-degree-of-freedom robot 6 having b
In addition, the tool 8 is operated in such a state that the tool 8 is gripped in this mounted state and various operations are given to the tool 8.
This operation is performed independently of the robot 6 after the positioning of the tool by the robot 6, whereby the tool 8 forms a small hole 10 having a predetermined diameter at a predetermined position, for example, in a non-contact state with the work 9. In this case, if the work 9 is a three-dimensional molded product, the mechanism of the multi-degree-of-freedom robot 6 needs to have five degrees of freedom with respect to the three-dimensional curved surface of the work, and the trajectory interpolation device 5 additionally has a circular motion mechanism and a radius. Two degrees of freedom are required for a setting mechanism (a hole diameter changing mechanism at a processing point), and a mechanism having seven degrees of freedom is premised on the entire system.

On the other hand, when the work 9 is a flat surface, the robot 6 functions with three degrees of freedom, so that a mechanism having five degrees of freedom is required in the entire system. Tools supported by the trajectory interpolation device 5 include a YAG laser gun, a carbon dioxide laser gun,
Various tools such as a plasma gun or a water jet gun are selected.

The trajectory interpolation device 5 basically gives numerical information such as the moving speed of the tool, the radius (or diameter) of the circular motion of the tool or the long side of the irregular shape, and is given in a preset range. The tool position is changed according to the numerical value. The function of determining the operation speed and the operation trajectory of the tool is independent of the operation of the main body of the robot 6, and the operation of the tool 8 is controlled by the trajectory interpolation device 5.

Next, the principle of trajectory interpolation of a circle by the trajectory interpolation device will be described with reference to FIGS. 2, 3 and 4. FIG. FIG. 2 shows an operation locus of a circular motion, and FIG. 3 is a characteristic diagram showing a relationship between a rotation angle and a radius of the circular motion. In FIG. 2, reference numeral 11 denotes a rotation shaft (hereinafter, T ₁ ) rotatably supported at the tip of the robot.
Axis). Rotation of the T ₁ shaft center 1
1 from the distance r only separated position operating shaft (hereinafter, T of ₂ axes) has become the center of rotation 12 of the. T ₂ shaft is supported by a T ₁ shaft, if rotation is T ₁ shaft, T ₂ shaft is T ₁ shaft and rotating integrally (revolution), and, T ₂ shaft independent of the T ₁ shaft (Rotation). Furthermore, (in Figure 2 omitted Tool 8) tool in position 13 spaced T is _biaxially from the center of rotation 12 by a predetermined distance gripping the. T ₂
The distance from the rotation center of the shaft to the tool position 13 is also equal to r. Thus, while keeping stationary the T ₁ shaft,
It is rotated the T ₂ shaft only tool moves along the circular path 14. Further, while keeping stationary the T ₂ shaft, it is rotated a T ₁ shaft only tool moves along the circular path 15.

[0012] Now, the line segment connecting the rotational center 12 and T ₁ rotation center 11 of the shaft of the T ₂ shaft, if the angle between a line segment connecting the center of rotation 12 and the tool position 13 of the T ₂ shaft θ , T
The distance between the _one- axis rotation center 11 and the tool position 13 is represented by a function R (θ) of θ, and has a relationship shown in FIG. Distance R
(Θ) is information on the radius of the circular motion of the tool (that is, the radius of the small hole to be machined), and is given to the trajectory interpolation device 5. Then, R (θ) can be uniquely determined by the following equation (1).

[0013]

(Equation 1) Therefore, from the radius R (θ) of the circular motion of the tool in equation (1), T
The rotation angle θ of the _two axes can be obtained by the following equation (2).

[0014]

(Equation 2) On the other hand, another information provided to the trajectory interpolation device 5, that is, the peripheral speed v (mm / sec) of the circular motion of the tool is represented by the following (3)
Formula and (4) the rotational speed omega ₁ of the motor of T ₁ shaft by formula
It can be converted to (number of peripheral teeth i ₁₎ and T ₂ the rotational speed of the shaft of the motor omega ₂ and (peripheral teeth i _2).

[0015]

(Equation 3) From the above relationship, the circular motion of the tool can be controlled according to the flowchart shown in FIG. In this control, first, information on the radius R (θ) of the circular motion of the tool and the peripheral velocity v are given (steps 20 and 21).
Information about the radius R (theta) is converted to the amount of movement of the T ₂ shaft for supporting the tool on the basis of the above equation (2), T ₂ shaft are determined rotation angle theta is T ₂ shaft is positioned on the angle theta (Step 22). On the other hand, information on the peripheral velocity
(3) (step 23) while being converted into the rotational speed omega ₁ of the motor of T ₁ shaft based, it is converted from the rotational speed omega ₁ of the T ₁ shaft motor rotation speed omega ₂ of the T ₂ shaft motor (Step 24). This basis T ₁ shaft motor and T ₂ shaft motor and each rotation speed omega _1, operate simultaneously omega _2, the tool rotates 360 ° or more, the small hole in the workpiece is established (step 25). After the opening of the small hole, the robot moves to position the tool at a predetermined position for opening the next small hole (step 26), and information about the small hole is given (steps 20 and 2).
1). Therefore, the circular operation of the tool is performed quickly and smoothly by the above operation, so that the small hole machining can be accurately performed regardless of the type of the tool and the size of the hole diameter.

Next, trajectory interpolation of a different shape will be described. Rectangular (including square), in the case of long holes, because of the directionality to the shape, not only the coordinate origin of the circular locus of the center of rotation of the T ₁ shaft as a circle trajectory interpolation, 5
(A), and starting point of the trajectory operated (S) to operate the T ₂ shaft, T ₁ shaft (b), the taught and stored. The origin is the locus center of irregular shape (C) is in the center of rotation of the T ₁ shaft is similar to the circular path. The numerical information gives the side A (mm) and the peripheral speed v (mm / sec).

Hereinafter, the trajectory formation control will be specifically described.

As shown in FIG. 6, the center of rotation of the T ₁ shaft and the coordinate origin (C), a line of Y axis connecting the coordinate origin and a start point (S), the street Y axis line perpendicular to the coordinate origin Let it be the X axis. The trajectory formation direction passes through the start point and is perpendicular to the Y axis. When the rotation angle of the T ₁ shaft theta _1, the rotation angle of the T ₂ shaft and theta _2, the tip of the coordinates of the tool 8 (5) below, can be uniquely determined as (6).

[0019] _{X = r cosθ 1 + r cosθ} 2 ... (5) Y = r sinθ 1 + r sinθ 2 ... (6) Since the start point (S) is taught, sides from moving angle theta ₀₂ of T ₂ shaft at the time B can be calculated.

[0020]

(Equation 4) From the numerical information A and the calculated value B, a locus of a rectangle or a long hole can be formed.

Here, the calculation of coordinate values at intervals of the control clock T (sec) is omitted because the information of the peripheral speed v (mm / sec) is too publicly known, and the coordinate values are calculated as shown in FIG. X ₁ , Y ₁ ) X ₁ = r cos θ ₁ + r cos θ ₂ (8) Y ₁ = r sin θ ₁ + r sin θ ₂ (9) From the equations (8) and (9), X ₁ −r cos θ ₁ = r cos θ ₂ … (10) From Y ₁ −r sin θ ₁ = r sin θ ₂ … (11) (10) ² + (11) ²

[0022]

(Equation 5) _{tanω = N / J, tanθ 0} = Y 1 / X 1 Thus _{tanθ 1 = tan (θ 0 =} ω) = (tanθ 0 - tanω) / (1+ tanθ 0 · tanω) = (Y 1 J-X 1 N) / (X ₁ J + Y ₁ N) θ ₁ = tan-1 {(Y ₁ J−X ₁ N) / (X ₁ J + Y ₁ N)} (14) Equation (14) is replaced with equations (10) and (11). Cos θ ₂ = (X ₁ −r cos θ ₁ ) / r sin θ ₂ = (Y ₁ −r sin θ ₁ ) / r tan θ ₂ = (Y ₁ −r sin θ ₁ ) / (X ₁ −r cos θ ₁ ) θ _{2 = tan-1 {Y 1} -r sinθ 1) / (X 1 -r cosθ 1) ... (15) where by T ₁ shaft for the tool to move from the starting point to the _{(X 1, Y 1),} T The rotation angles of the _two axes can be represented as θ ₁₁ and θ ₂₂ as shown in FIG. 8, and θ ₁₁ = θ ₁ −θ ₀₁ (16) θ ₂₂ = θ ₂₂ + 180 ° −θ ₁ (17 ) (although it is possible to obtain a theta ₀₁ = a 180 ° -θ _02/2).

Based on the above principle, a locus of a rectangle or a long hole is formed in accordance with the flowchart of FIG. That is, in step 91, the side A (mm), the peripheral speed v of the tool 8
(Mm / sec) is input, and in step 92, the side B (mm) is calculated by equation (7). And step 93
Then, coordinate values for forming a rectangle and a long hole are calculated from equations (8) and (9), and T ₁ and T ₂ are calculated in step 94 according to equations (14) to (17).
The rotation angles θ ₁₁ and θ ₂₂ of the shaft are calculated. Thus T ₁ ,
T ₂ axes of rotation angle theta _11, by rotating so as to theta _22, the locus of the desired different shape at step 95 is formed by the tool 8, step 93 to 95 are repeated until the end of the trajectory formed Upon completion, the robot moves at step 96 to correspond to another perforated portion.

In the present invention, information on the peripheral speed, radius, and long side of the tool is given to the trajectory interpolation device 5, and the tool is moved from a set start point. The tool can be directly controlled independently of the movement, and can be made to perform a circular operation, a rectangular operation, and a long hole operation.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIGS. 10, 11 and 12 are a longitudinal sectional view, a front view and a rear view of a first embodiment of a trajectory interpolating device constituting the present invention. The case 30 has a cylindrical front end portion and a rear end portion whose inner and outer dimensions are slightly larger than the above, and whose end is covered with a cover 31. A flange 32 is integrally formed on one side wall (each lower side in the drawing) of the rear end, and the flange 32 is attached to the wrist at the tip of the arm 7 b of the robot 6. Further, the corner of the other side wall (each upper part of the drawing) at the rear end has a shape similar to a rectangular cylindrical wall protruding outward, and T ₁ is provided on the outside of the cover 31 corresponding to this corner. and T ₂ shaft motor 34 for rotating the T ₁ shaft motor 33 and the T ₂ shaft for rotating the shaft is mounted side by side.

The inside of the front end portion of the case 30, via two bearings 35 disposed in the axial direction, the tubular T ₁ shaft (rotary shaft) 36 is rotatably mounted. T ₁ shaft 36 and a rear end portion which is inserted inside the bearing 35, Case 3
It has a tip that protrudes in the axial direction from zero. The rear end of the T ₁ shaft 36 has an inner surface substantially concentric with the center of rotation. In contrast, the distal end portion of the T ₁ shaft 36 has a larger outer diameter than the rear end portion, and has an inner surface which is eccentric with respect to the center of rotation. The amount of eccentricity is equal to the distance r shown in FIG. Then, the inside of the eccentric tip, via two bearings 37 disposed in the axial direction, a cylindrical T ₂ axis (motion axis) 38 is rotatably mounted.

The T ₂ shaft 38 also has an inner surface eccentric to the center of rotation. The amount of eccentricity is also equal to the distance r shown in FIG. Then, the tool 8 is attached to the eccentric position as the point of action and the inner or center of rotation of the T ₂ shaft 38. In this case, for example, a laser gun is used as the tool 8, and the tool is rotatably supported on the tool mounting member 40 via two bearings 39 arranged in the axial direction. There is coupled to the distal end surface of the T ₂ shaft.

On the other hand, on the inside of the rear end portion of the T ₁ shaft 36, T
Cylindrical drive transmission shaft 41 for transmitting rotational movement to _two shafts 38
Are rotatably mounted via two bearings 42 arranged in the axial direction. And the distal end surface of the drive transmission shaft 41, the rear end surface and is eccentrically movably mutually facing T ₂ shaft 38, the constant velocity coupling 43 is provided therebetween. That is, the rotation of the drive transmission shaft 41, via the constant velocity coupling 43, and transmitted to the T ₂ shaft 38. Incidentally, the hole is bored in the axial center of the constant velocity coupling 43, T ₂ shaft 38, the constant velocity coupling 43, and the cable 44 is passed through the axial center of the drive transmission shaft 41 and the aforementioned cover 31 Thus, the machining energy can be supplied to the tool 8 without any hindrance to the eccentric movement of the tool 8.

A gear 45 is mounted on the rear end surface of the drive transmission shaft 41 concentrically with the center of rotation. The gear 45 has a hole through which the cable 44 is inserted. Furthermore, gear 46 is mounted in concentric with its center of rotation to the rear end surface of the T ₁ shaft 36. Holes that pass T ₂ shaft 41 is formed in the gear 46. The small gear 4 attached to the output shaft of the T ₁ shaft motor 33
7 meshes with the gear 46, further pinion (not shown) attached to the output shaft of the T ₂ shaft motor 32 is in mesh with the gear 45.

FIG. 13 is an exploded perspective view of an Oldham coupling used as the constant velocity coupling 43. This is a joint used when two axes to be connected are not in a straight line even if they are parallel, and flanges 43A and 43B attached to ends of the two axes are connected via an intermediate piece 43C. At this time, the flanges 43A and 43B at the shaft ends and the intermediate piece 43C fit into grooves and projections provided in the diametrical direction, and the two sets of fittings are provided at right angles to each other. It is. The intermediate piece 43C performs an elliptical motion and transmits the motion between two eccentric axes. Holes 48 are provided in the respective flanges at the shaft end and at the respective shaft cores of the intermediate pieces so that the cables can pass therethrough. Incidentally, the relationship between the motion trajectories in FIG. 2 can be similarly expressed in FIG. 11, thereby enabling control based on the above principle.

FIGS. 14 and 15 are a vertical sectional view and a front view, respectively, of a second embodiment of the trajectory interpolating device according to the present invention. Elements that are the same as in the first embodiment are given the same reference numerals. The description is omitted.

[0032] Here, T ₁ shaft 36 is provided with a first hole and a second hole for supporting the shaft within each. The first hole supports the drive transmission shaft 41 inside, and the second hole
The holes and supports the T ₂ shaft 38 therein. The axes of the first and second holes are parallel to each other and are separated from each other by a distance r. In the first hole, a drive transmission shaft 41 is rotatably supported via a bearing 42, and in the second hole, a T ₂ shaft 38 is provided via a bearing 37.
Are rotatably supported. In this case, the drive transmission shaft 4
A gear 51 is formed on the outer peripheral surface of the tip end of the T ₂ shaft 38.
A gear 52 is also formed on the outer peripheral surface of the tip of the gear, and these gears mesh with each other. Further, the front end surface of the T ₂ shaft end of the arm 53 is fixed by bolts. The tool 8 is rotatably supported at the other end of the arm 53 via a bearing 39. The rotational center or rotational center of the action point and the T ₂ shaft of the tool 8 are separated by a distance r, as previously described.

The rear end of the tool 8 has a drive transmission shaft 41
Of being adapted to be moved inside, rotates the T ₁ shaft by T ₁ shaft motor 33, a drive transmission shaft 41 T ₂
By rotating the shaft motor 34, the T ₂ shaft 38 can rotate and revolve, and the relationship between the operation trajectories in FIG. 2 can be similarly expressed in FIG. Based control becomes possible.

In the above embodiment, a laser gun is used as a tool. However, the present invention is not limited to this, and a plasma gun or a water jet gun may be used.

[0035]

As is apparent from the above description, according to the present invention, even when a three-dimensional molded product is drilled such as a body part of an automobile, the size of the three-dimensional molded product and the type of tool used are not affected. It is possible to quickly and smoothly form a circular hole, a rectangular hole, and a long hole having an accurate diameter at an accurate position.

Further, according to the present invention, the drive transmission shaft is supported inside the rotary shaft having a cylindrical shape, and a cable for transmitting energy to the tool is passed through the axis of the drive transmission shaft. Therefore, the effect that the cable processing which is a problem in the xy table or the like is facilitated is also obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a basic structure of the present invention.

FIG. 2 is a conceptual diagram showing a trajectory for determining a circular motion.

FIG. 3 is a characteristic diagram showing a relationship between a rotation angle and a radius of a circular motion.

FIG. 4 is a flowchart illustrating an example of control of a circular operation.

FIG. 5 is an explanatory diagram of information provided for forming a trajectory in a rectangular hole or a long hole (irregular shape).

[6] T ₁ shaft at the start operation of the different shapes, T ₂ shaft rotation center position relationship diagram

FIG. 7 is an explanatory view of coordinate values at arbitrary points on the long side of the irregular shape and rotation angles of the T ₁ and T ₂ axes.

FIG. 8 is an explanatory view of coordinate values at arbitrary points on the long side of the irregular shape and rotation angles of the T ₁ and T ₂ axes.

FIG. 9 is a flowchart illustrating an example of control of a different shape operation.

FIG. 10 is a longitudinal sectional view of a main part of the first embodiment of the present invention.

FIG. 11 is a front view of a main part of the first embodiment of the present invention.

FIG. 12 is a rear view of a main part of the first embodiment of the present invention.

FIG. 13 is an exploded perspective view of a constant velocity coupling included in the first embodiment.

FIG. 14 is a longitudinal sectional view of a main part of a second embodiment of the present invention.

FIG. 15 is a front view of a main part of a second embodiment of the present invention.

FIG. 16 is a side view of a conventional apparatus that performs small hole processing.

[Explanation of symbols]

5 the locus interpolation device 6 robot 7a, 7b list 8 tools 36 rotating shaft (T ₁ shaft) 38 operating shaft (T ₂ shaft) 41 drive transmission shaft 43 constant velocity coupling 44 cable

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B25J 17/02 B25J 17/02 A G05B 19/18 G05B 19/18 C (56) References JP JP-A-63-62694 (JP, A) JP-A-59-174278 (JP, A) JP-A-60-11702 (JP, U) JP-A-61-31580 (JP, U) Journal of "Robot" (No. 20) ) September 10, 1978 (Japan) Robot Industry Association of Japan P, 45-48

Claims (3)

(57) [Claims] 1. A robot apparatus comprising a robot (6) and a trajectory interpolation device (5) attached to an arm of the robot, wherein the trajectory interpolation device (5) A cylindrical rotating shaft (36) rotatably supported around the axis; and a rotatable and revolvable support at the tip of the rotating shaft, and separated by a predetermined distance from the rotation center of the rotating shaft. An operating axis (38) for holding the tool (8) such that the point of action of the tool (8) is located at a position separated by a predetermined distance from the center of rotation, A cylindrical drive transmission shaft (41) that is rotatably supported on the inside of the rotation shaft about an axis parallel to the axis of the rotation shaft, and that transmits a driving force to the operation shaft; A cable (44) passed through the shaft center of the shaft and transmitting energy to the tool. The locus interpolation device (5) is a robot device for moving along the trajectory of a circle and different shapes of the tool by controlling the rotary shaft and the operation shaft independently of the operation of the robot arm. 2. The method according to claim 1, wherein the trajectory interpolating device (5) uses a rotation center of the rotation axis as a coordinate center, and obtains a tip of the tool according to numerical information of a radius, a long side, a short side, etc. of a circle and an irregular shape. 2. The robot apparatus according to claim 1, wherein the rotation axis and the movement axis are controlled so as to form a trajectory. 3. The trajectory interpolation device (5) comprises: a constant-speed coupling (43) between the drive transmission shaft and the operation shaft.
The robot device according to claim 1, wherein the robot device is connected by: