JPH0369671B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is a direct teaching method in which a robot is manually operated to teach work contents to create a program, and the program is reproduced to execute the work. The present invention relates to an articulated robot.

(Prior Art) Recently, in order to make teaching easier, direct teaching type robots such as hydraulic painting robots are being reconsidered as well as articulated robots using electric motors and large reduction gears. For example, if a so-called electric linear actuator with a speed reducer that combines a screw and a nut is used as a drive source and is installed between a fixed side and a movable side of a robot, an operator can grasp the movable side. Even if you try to manually operate this, the speed reducer acts as a resistance and it is impossible. Therefore, in order to enable manual operation, the electric motor type linear actuator can be removed from the robot and reattached when regenerating, but this work is difficult and time consuming.

(Problems to be Solved) This invention has been made in view of the above-mentioned circumstances, and even in a robot that uses the electric motor linear actuator as a drive source, the electric motor linear actuator is not activated during teaching and playback. It is an object of the present invention to provide an actuator that can be easily switched without having to remove or reinstall the actuator.

(Means for Solving the Problems) The present invention provides an electric motor linear actuator as a drive source that is interposed between a fixed side and a movable side of a robot and that connects fluid pressure linear actuators in series. and piping is connected to the hydraulic linear actuator, and during teaching, both cylinder chambers of the hydraulic linear actuator are opened to set the hydraulic linear actuator in a free state, and during regeneration, In some cases, it is equipped with a switching valve that applies fluid pressure to either one of the two cylinder chambers to lock the fluid pressure linear actuator in the most contracted state or the most extended state. .

(Function) During teaching, if both cylinder chambers of the hydraulic linear actuator are opened to allow free expansion and contraction, the robot can be moved by the operator's manual operation without removing the motorized linear actuator. You can easily move the sides. Further, during regeneration, if fluid pressure is applied to either one of the two cylinder chambers to lock the fluid pressure type linear actuator, the driving force from the electric motor type linear actuator can reliably move the robot. transmitted to the side.

(Example) Examples will be described in detail below. Although this embodiment will be described as a six-axis multi-joint arc welding robot in which the drive sources for the three axes on the proximal end are motorized linear actuators, the present invention is not limited to this embodiment.

Reference numeral 1 denotes a base of the robot, on which a pillar 1a is erected.

2 is the first pivot 2a (horizontal pivot) on the top of the column 1a.
This is the first rotating arm that can be rotated in the _α1 direction. Further, at the upper part of the column 1a, the middle part of a triangular link 3 is rotatably horizontally supported 3a, and between one end of the link 3 and the arm 2 is a first hydraulic linear actuator FA ₁ ( In the embodiment, the pneumatic type) is the shaft mounting 4a,
4b. Further, between the base 1 and the other end of the link 3, first electric linear actuators MA ₁ for the α ₁ axis of the arm 2 are pivotally mounted 5 a and 5 b. Note that an encoder _E1 is connected to the shaft 2a.

6 is a first universal joint 7 at the tip of the arm 2 (in the embodiment, a second shaft 7a in a direction perpendicular to the shaft 2a and this shaft 7
This is a second rotating arm that is supported so as to be swingable in the α ₂ direction and the α ₃ direction via a third axis 7b (including a third axis 7b orthogonal to a). A handle 6a is provided at the tip of the arm 6. In addition, at both ends of the shaft 2a, intermediate portions of triangular links 8 and 9 are rotatably provided with horizontal shaft supports 8.
a, 9a (however, 9a is not shown).
Between one end of the link 8 and the arm 6, a second
A second hydraulic linear actuator FA ₂ (pneumatic in the embodiment) is supported by the third universal joints 10 and 11, and between one end of the link 9 and the arm 6, fourth and fifth universal joints 12 are supported. , 13 support a third hydraulic linear actuator FA ₃ (pneumatic in the embodiment). Furthermore, base 1 and links 8 and 9
The second and third electric linear actuators MA ₂ and MA ₃ are connected to the other ends of the shafts 14a and 14a, respectively.
14b, 15a, and 15b (however, 15b is not shown). E ₂ is an encoder connected to the shaft 7a, and E ₃ is an encoder connected to the shaft 7b.

By the way, the third and fifth universal joints 11 and 13 are modified joints, and are constructed as shown in FIG. 2. That is, first levers 11b and 13 are connected to both sides of the arm 6 by shafts 11a and 13a parallel to the shaft 7b.
b is rotatably supported, and each lever 11
A second shaft is connected to the tips of b and 13b by shafts 11c and 13c.
The levers 11d and 13d are rotatably supported, and the tips of the levers 11d and 13d are connected to shafts 11e and 13e coaxial with the actuators FA ₂ and FA ₃ , respectively.
These actuators can be rotated freely by FA ₂ ,
It is supported by the FA ₃ piston rod. Moreover, each axis 11a, 11c, 11e, 13a, 13c,
13e are set to intersect at one point _O1 .

T is a welding torch supported on the arm 6 so as to be swingable in three dimensions.

The configuration of the three-dimensional swing device for the torch T, that is, the wrist device C will be described below with reference to FIGS. 3 to 5.

21 to 23 are a fourth shaft support 21 coaxially on the arm 6;
a, a fifth pivot 22a, and a sixth pivot 23a, which are the first arm, second arm, and third arm, respectively. and arm 21
A first link 24 is provided at the tip, a second link 25 is provided at the tip of the arm 22, and a third link 26 is provided at the tip of the arm 23.
5a, 26a. Furthermore, each link 24
A rocking body 27 is supported by shafts 27a to 27c at the tip of ~26.
This oscillating body 27 is configured as a holding member for the torch T. The axes 21a to 26a and the axes 27a to 27c are set such that their axial center lines intersect at one turn _O2 . Further, each of the shafts 21a to 23a has a point on its axial center line.
O ₁ is set to exist. Further, gears 28 to 30 having the same diameter are integrally provided on each of the shafts 21a to 23a. Furthermore, encoders E ₄ to _{E 6} are attached to the arm 6, and each encoder E ₄ to
Gears 31 to 33 are integrally provided on the shaft of E ₆ ,
It is meshed with gears 28-30.

34 to 36 are attached to the arm 6 and to the shafts 21a to 23a.
A first working arm, a second working arm, and a third working arm are pivotably supported at 120 degree intervals on the circumference with respect to the axial center line of be. Rotary electric motors M ₁ to _{M 3} with reduction gears are attached to the tips of each of the arms 34 to 36, and gears 37 to 39 of the same diameter that mesh with the gears 28 to 30 are integrally provided on their output shafts. It is being Further, one end of a fourth fluid pressure type linear actuator FA ₄ (pneumatic type in the embodiment) is supported by a sixth universal joint 40 on the arm 6 substantially coaxially with the shafts 21a to 23a. A rod 43 is connected between the other end of the actuator FA ₄ and the arm 34 via seventh and eighth universal joints 41 and 42, and a ninth and tenth rod is connected between the other end and the arm 35. Universal joint 4
4 and 45, and between the other end and the arm 36 there are eleventh and twelfth universal joints 47,
Rods 49 are connected via 48, respectively. Further, the shaft 21a for each arm 34 to 36
At the position opposite to the axial center line of ~23a,
Stoppers 50 to 52 integral with the arm 6 are provided in a protruding manner.

When the actuator FA ₄ is retracted, the arms 34 to 36 are rotated in a direction in which their tips approach each other, so that the gear 37 is connected to the gear 28, the gear 38 is connected to the gear 29, and the gear 39 is connected to the gear 30, respectively. Conversely, when the actuator FA ₄ is extended, the tips of the arms 34 to 36 are rotated in a direction in which they are separated from each other so that the gear 37 is connected to the gear 28, the gear 38 is connected to the gear 29, and the gear 38 is connected to the gear 29. 39 is gear 3
0, and each arm 34-36 is configured to abut each stopper 50-52.

In addition, each actuator FA ₁ to _{FA 4} is connected to a pressure source 5.
3 (air pressure source) and a switching valve 54 as shown in FIG.

_B1 is a control device for this robot using the PTP method. B ₂ is its operation panel, which controls the welding voltage,
Switches are provided for current, welding speed, various interpolation functions, etc. Furthermore, a storage command switch S is provided on the handle 6a.

Next, the operation of this embodiment will be described.

It is assumed that the switching valve 54 is now in the left position as shown in FIG. At this time, compressed air from the pressure source 53 flows only into the piston side of the actuator FA ₄ , the actuator FA ₄ is in an extended state, and the other actuators FA ₁ to _{FA 3} are in a free state. That is, both cylinder chambers of each of the actuators FA ₁ to _{FA 3} are opened and are in a state where they can freely expand and contract.

Therefore, by extension of actuator FA ₄ , each arm 34-36 is rotated in a direction in which their respective tips are remote from each other. Then, each gear 37-39 separates from each gear 28-30, and finally each arm 34-3
6 comes into contact with each of the stoppers 50 to 52 as shown in FIG. 5, and eventually each shaft 21a to 23a is disconnected from the electric motors _M1 to _M3 and becomes a freely rotating shaft.
The rocking body 27 can now be manually rocked into any position. Furthermore, due to the free state of the actuators FA ₁ to _{FA 3} , each arm 2, 6 can also be manually rotated arbitrarily in the α ₁ to _{α 3} directions.

Therefore, the operator handles the handle 6a as shown in Fig. 7.
Holding the oscillating body 27, place the torch T against the workpiece.
The position and orientation of the controller are sequentially determined, the switch S is operated while these positions and orientations are held, and each piece of information at that time is sequentially recorded in the control device _B1 via the encoders _E1 to _E6 . In this way, the operator
The position and posture of the torch T can be taught directly.

Furthermore, play the recorded program,
When actually operating the robot, first switch the switching valve 54 to the right position. Then, compressed air from the pressure source 53 flows into the piston rod side of each actuator FA ₁ to FA ₄ , _and
All FA ₄ are in a contracted state. Therefore, depending on the contracted state (locked state) of actuators FA ₁ to FA ₃ ,
In the case of actuator FA ₁ , it becomes a mere connecting rod between arm 2 and link 3, and in the case of actuators FA ₂ and FA ₃ , it becomes a mere connecting rod between arm 6 and links 8 and 9. become. That is, each arm 2, 6 is an actuator MA ₁ to _{MA 3}
It is now in a state where it can be driven by. Further, due to the contraction of the actuator FA ₄ , each of the arms 34 to 36 rotates in a direction in which their tips approach each other, and each gear 3
7-39 are meshed with each gear 28-30. At this time, the peaks of gears 37 to 39 and gears 28 to 30 may come into contact with each other and may not mesh temporarily.
In that case, one end of actuator FA ₄ is connected to joint 4.
Since the actuator FA 4 is supported on the arm 6 via the arm 6, the actuator FA ₄ swings and finally becomes securely engaged. Therefore, each of the shafts 21a to 23a is connected to the electric motors M ₁ to M ₃ as shown in FIG. 4, and is ready to drive the oscillator 27.

Based on the recorded program, commands are output from the control device _B1 , the position and posture of the torch T are controlled, and the workpieces are automatically welded.

Note that the joints 11 and 13 are designed so that the axial center lines of the shafts 11e and 13e always coincide with _{the O1} point.
It is easy to calculate the position of the arm 6 relative to the arm.

The above description is an example, and for example, the actuators FA ₁ to _{FA 3} may be set in a locked state when they are in an extended state. It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

(Effects) As described above, this invention connects a fluid pressure linear actuator in series with an electric motor linear actuator interposed between the fixed side and the movable side of the robot, and A switching valve connected to the hydraulic linear actuator via piping opens both cylinder chambers of the hydraulic linear actuator during teaching so that it can freely expand and contract, and during playback, fluid is supplied to either of the two cylinder chambers. Since the fluid pressure type linear actuator is locked in the most contracted state or the most expanded state by applying pressure, it is not possible to remove or reinstall the electric motor type linear actuator during teaching and playback as in the past. There is no need to In other words, switching between teaching and playback is easy.

[Brief explanation of drawings]

Each of the figures shows an embodiment of the present invention.
The figure is an overall perspective view of the articulated robot, and the second figure is the first one.
3 is a perspective view of the vicinity of the welding torch of the three-dimensional swing device (wrist device), FIG. 4 is a perspective view of the vicinity of the drive source of the three-dimensional swing device, and FIG. FIG. 6 is a piping diagram, and FIG. 7 is an explanatory diagram of the direct teaching state. In the figure, 1... base, 2... first rotating arm,
2a...first axis, 6...second rotating arm, 7...first
Universal joint, 7a...second axis, 7b...third axis,
MA ₁ ...First electric motor linear actuator,
MA ₂ ...Second electric motor linear actuator,
MA ₃ ...Third electric motor linear actuator,
FA ₁ ...First fluid pressure linear actuator, FA ₂
...Second fluid pressure linear actuator, FA ₃ ...
A third fluid pressure linear actuator, 54...a switching valve.

Claims (1)

[Claims] 1. In a direct teaching type multi-jointed robot in which a program is created by manually operating the robot and teaching the work contents, and the program is played back to execute the work, there is a gap between the fixed side and the movable side of the robot. an electric motor linear actuator as a drive source which is connected in series with a hydraulic linear actuator; and a piping connection to the hydraulic linear actuator; Both cylinder chambers of the motor are opened to set the hydraulic linear actuator in a free state, and during regeneration, fluid pressure is applied to either one of the two cylinder chambers to free the hydraulic linear actuator. The multi-jointed robot is provided with a switching valve that locks the eta in the most contracted state or the most expanded state.