JPH0621674Y2 - Parallel link type vertical articulated robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a parallel link type vertical articulated robot.

[Conventional technology]

A vertical articulated robot according to the related art has a second arm rotation motor and its deceleration mechanism installed at the pivot point of the second arm at the tip end portion of the first arm. The weight of the deceleration mechanism is added to the weight of the robot member beyond the second arm, and the load on the first arm becomes very large. Therefore, the dimensions of the first arm rotation motor and the speed reducer also become large. To avoid this, gravity compensation is performed with a balance wayro or balance spring.

In addition, in the parallel link type vertical articulated robot,
The arm rotation motor and its speed reduction mechanism are installed coaxially with the first arm rotation motor at the first arm base.

[Problems to be solved by the device]

The load compensation for the first arm in the vertical articulated robot according to the conventional technique as described above requires the balance weight and the balance spring, and the load compensation is insufficient and the weight is added. There is a disadvantage. In addition, a separate means is required for compensating the load on the second arm, and without it, the second arm rotating motor would be large and would be even more disadvantageous.

In the case of the parallel link type vertical articulated robot, the first arm using the second arm rotating motor and the speed reducing mechanism thereof is different from the above case.
Although the load on the arm is reduced, the problem of load due to the weight moment of the second arm and its tip member and the problem of load on the second arm remain.

[Means for Solving the Problems]

A parallel link type vertical articulated robot according to the present invention has a second link parallel to a first arm whose base is pivotally mounted so as to be rotated by a driving device and a second arm pivotally mounted to a tip of the arm. A parallel first link is provided, and an extension is formed at the base of the first arm beyond the pivot point, and the base of the second arm extends beyond the pivot point with the first arm end. Part is formed,
The other end of the first link whose one end is pivotally attached to the first arm extension and the other end of the second link whose one end is pivotally attached to the second arm extension are pivotally attached to each other. A two-arm rotating drive device is mounted.

[Action]

In the parallel link type vertical multi-joint robot, when the driving device for rotating the second arm is driven to rotate, the second link rotates in the direction of narrowing or widening the angle with the first link. The second link rotates about the pivot point of the first arm with respect to the first arm by the shaped link mechanism. That is, when the second arm rotates about the pivot point of the base of the second arm as a fulcrum, the second arm rotation drive device, together with the extension of the second arm, the first link, and the second link, It also works as a balance weight on the opposite side of the arm extension.

Further, even when the first arm rotates about the pivot point of the base portion of the first arm as a fulcrum, the second arm rotation drive device includes the extension of the first arm, the first link, and the second link (partial). ), And operates as a balance weight on the side opposite to the extension of the first arm.

〔Example〕

An embodiment of this invention will be described with reference to the drawings. Fixed base 1
A swivel base 2 is rotatably mounted on the upper surface of the swivel base 10 around an upright axis l0, and an upright support portion 3 is formed at an outer peripheral position of an upper surface of the swivel base 2.

The base of the first arm 4 is pivotally attached to the upright supporting portion 3 so as to be rotatable about the first horizontal axis l1, and the base of the second arm 5 is attached to the upper end of the first arm 4 by the first horizontal axis l1. It is pivotally attached about a second horizontal axis l2 parallel to. The base portions of the first arm 4 and the second arm 5 are respectively formed with extension portions 6 and 7 which are short in the longitudinal direction, and at the tip of the extension portion 6 of the first arm 4, the third extension parallel to the first horizontal axis l1 is formed. One end of the first link 8 is pivotally attached so as to be rotatable about the horizontal axis l3, and the end of the extension portion 7 of the second arm 5 is rotated about the fourth horizontal axis l4 parallel to the first horizontal axis acid 1. The upper end of the second link 9 is rotatably attached, and the other end of the first link 8 and the lower end of the second link 9 are rotatable about a fifth horizontal axis l5 parallel to the first horizontal axis l1. It is pivotally attached. Then, the opposing horizontal axis intervals are equal to each other, and the first arm 4, the second link 9, the extension 7 of the second arm 5 and the first link 8 constitute a parallelogram link mechanism.

On the upper surface of the swivel base 2, a swivel rotary drive servo motor M1
On the upright axis l0, at the base of the first arm 4, the first arm rotation driving servomotor M2 is on the first horizontal axis l1, and on the first link 8 or the second link 9, Arm rotation drive servomotors M3 are mounted on the fifth horizontal axis l5, respectively.

In addition, a twisting portion 10 is rotatably rotatable about an axis l6 as an extension of the second arm 5 at an end thereof, and a twisting portion 10 is rotatable at an end of the twisting portion 10 about an axis l7 perpendicular to the axis l6. On the wrist
Further, a tool attaching portion 12 is attached to the wrist portion 11 so as to be rotatable around an axis line l8 perpendicular to the axis line l7.

Then, at the end of the extension portion 7 of the second arm 5, the twisting portion 10 rotation driving servomotor M4 is provided, and inside the tip end portion of the second arm 5, the wrist portion 11 rotation driving servomotor M4. A motor M5 is attached to the wrist 11, and a servomotor M6 for rotating the tool attachment portion 12 is attached to the wrist 11.

The output shaft of the servo motor M1 is mounted on the fixed base 1, the output shaft of the servo motor M2 is mounted on the upright bearing 3, and the output shaft of the servo motor M3 is mounted on the second link 9 (when the first link of the servo motor is mounted). ), Or the first link 8 (when the second link of the servo motor is mounted), the output shaft of the servo motor M4 is a twisted portion.
10, the output shaft of the servo motor M5 is connected to the wrist portion 11, the output shaft of the servo motor M6 is connected to the tool mounting portion 12 via an appropriate mechanism such as a reduction mechanism, respectively, according to an input signal. The rotationally driven member is driven to rotate.

A DD motor may be used instead of the servo motors M1 to M6 for each rotation drive, and the reduction mechanism may be omitted.

FIG. 6 shows a skeleton of the parallel link type vertical articulated robot.

As a preferable condition for the equilibrium state, ideally, with respect to the positional relationship between the weight and the center of gravity of each part of the robot, in FIG. 6, the moment ml about the first horizontal axis l1 is zero,
The total center of gravity may be added to the fulcrum on the first horizontal axis l1.

Furthermore, the momentum m2 around the second horizontal axis l2 may be zero.

ml = W1 ・ a + W2 ・ b + W3 ・ c + W4 ・ d- (W5 ・ e + W6 ・ f + W7 ・ g + W8 ・ h) m2 = W1 ・ a '+ W2 ・ b'-(W3 ・ c '+ W6 ・ f' + W7 ・ g '+ W8 ・
h ') W1 is the weight of the hand attached to the tool mounting part 12, W2
Is the total weight of the twisting part 10, the wrist part 11 and the tool mounting part 12, W3
Is the weight of the second arm 5 including the extension 7, and W4 is the first arm 4
, W5 is the weight of the extension 6 of the first arm 4, and W6 is the first
The weight of the link 8, W7 is the weight of the servomotor M3 for rotating and rotating the second arm, W8 is the weight of the second link 9, and
h, a'-h 'are moment arm lengths of the center of gravity of each part.

Regarding the positional relationship between the weight and the center of gravity of each part of the robot, it is ideal if the fifth horizontal axis l5 is located on the extension line of the straight line X connecting the load center of gravity W1 and the first horizontal axis l1 or slightly below the extension line. Close to equilibrium.

The operation of the parallel link type vertical articulated robot will be described.

When the servo motor M1 for rotating the swivel base is rotationally driven, the swivel base 2 rotates about the upright axis l0 with respect to the fixed base 1,
Therefore, the first arm 4 to the tool mounting portion 12 integrally rotate about the upright axis l0, and the first arm rotation driving servomotor M2.
When rotationally driven, the first arm 4 rotates about the first horizontal axis l1 with respect to the upright support portion 3, that is, the swivel base 2. Further second
When the arm rotation driving servomotor M3 is rotationally driven, the second link 9 rotates about the fifth horizontal axis l5 with respect to the first link 8, and thus the parallelogram linkage mechanism (4, 6, 7, 8). , 9) causes the second arm 5 to rotate about the second horizontal axis l2 with respect to the first arm 4.

When the servomotor M4 for driving the rotation of the twisting portion is driven to rotate, the twisting portion 10 rotates the servomotor M5 for driving the rotation of the wrist portion around the axis l6 with respect to the second arm 5 to twist the wrist portion 11. When the servomotor M6 for rotating the tool mounting portion 12 is rotated about the axis l7 with respect to the portion 10, the tool mounting portion 12 rotates about the axis l8 with respect to the wrist portion 11, respectively.

Then, since each rotation drive motor is driven to rotate at a desired rotation angle by a control device (not shown), the rotation of the swivel base 2 to the tool mounting portion 12 is decelerated by the speed reduction mechanism, respectively. The rotation is at the desired angle, and eventually the tool mounting part 12
A suitable work tool, such as a welding torch, mounted on the robot moves in a desired position in a desired angular posture.

In the above operating state, the entire structure has the first horizontal axis l1.
When the fulcrum is used as the fulcrum, the second arm rotation drive motor M3 / deceleration mechanism, together with the extension portion 6 of the first arm 4, the first link 8 and the second link 9 (portion), is the structure portion on the work tool side. In contrast, it operates as a balance weight in the structure portion on the opposite side. Similarly, when the second arm 5 rotates about the second horizontal axis l2 as a fulcrum, the second arm rotation drive motor M3 / deceleration mechanism includes the extension portion 7, the first link 8 and the second arm 8 of the second arm 5. Together with the link 9, it also acts as a balance weight on the extension 7 side with respect to the structure portion on the opposite side of the extension 7 of the second arm 5.

First arm 4, extension 6, second arm extension 7, first link 8
Since the second link 9 and the second link 9 form a parallelogram link mechanism, the balance weight operation described above is effective regardless of the posture of each arm even when the robot is suspended from the ceiling.

[Effect of device]

In the parallel link type vertical articulated robot according to the present invention, the first link is pivotally attached to the extension portion of the first arm, and the second arm rotation drive device is attached to the pivot point of the first link and the second link. Therefore, with respect to the rotation around the pivot point of the first arm base portion and around the pivot point of the second arm base portion, the first link, the second link, and each arm extension portion work reliably as a balance weight. Therefore, the balance weight and the balance spring for compensating the load on the first arm are unnecessary, the weight can be reduced, and the outputs of the drive devices for rotating the first arm and the second arm can be made small without increasing the output. be able to.

[Brief description of drawings]

FIG. 1 is a front view of a parallel link type vertical articulated robot according to an embodiment of the present invention, FIG. 2 is a left side view of the same, FIG. 3 is a plan view of the same, and FIG. 4 is a rear view of the same. FIG. 5 is an enlarged partial view of the right side surface of the same, and FIG. 6 is a skeleton diagram showing a moment relation of each part of the parallel link type vertical articulated robot in the embodiment of the present invention. 1: Fixed base, 2: Revolving base 3: Upright support part, 4: First arm, 5: Second arm, 6,7: Extension part, 8: First link, 9: Second link, 10: Twisted part, 11 : Wrist 12: Tool mounting part l1 to l5: 1st to 5th horizontal axis l6 to l8: Axis M1 to M6: Servo motor for rotation drive

Claims (1)

[Scope of utility model registration request] 1. A second link parallel to a first arm whose base is pivotally mounted so as to be rotated by a drive device and a first link parallel to a second arm pivotally mounted to a tip of the first arm. A parallel link type vertical multi-joint robot having an extension part formed at a base portion of a first arm beyond a pivot point, and a base point of the second arm having a pivot point with a first arm end. An extension is formed over there,
The other end of the first link whose one end is pivotally attached to the first arm extension and the other end of the second link whose one end is pivotally attached to the second arm extension are mutually pivoted, and at this pivot point Parallel link type vertical articulated robot equipped with a drive device for rotating the second arm