JPS6161776A - Industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention enables precise transfer of work objects on a flat surface.

This invention relates to a horizontal articulated link type industrial pot for assembly work.

Configuration of conventional example and its problems As shown in Figure 1, the concrete configuration of a conventional industrial robot for flat surface work is a horizontal articulated robot with serial arms, called a scalar robot7). The majority.

This includes a first arm 3 that is rotatably coupled to a support column 2 that is integrated with the pace 1, and a first motor 4 that drives this arm.
Generally, it has a first reduction gear +5 (not shown) represented by a harmonic reduction gear, and a second arm 6 rotatably coupled to the other end of the first arm, and a second arm 6 for driving this. It has a second motor 7 and a second speed reducer 8 (not shown), and further has a second motor 7 and a second speed reducer 8 (not shown).
The other end of the arm is interlocked with a vertical movement actuator 9 (generally a small motor equipped with a fluid cylinder or a speed reduction means such as a ball screw) and a motor actuator 1o attached to the column 2, and is transmitted by a timing belt 11 or the like. It is equipped with a rotation means that can be rotated.

However, the above configuration has the following problems.

(1) Since a reducer is used, there is play in the reducer.

Errors accumulate at the tip due to panocranon, etc., resulting in poor positioning accuracy.

(2) A large load acts on the end of the reducer, and the natural frequency of the entire arm is low due to the lack of rigidity of the reducer itself.
Vibrations are large and speed limits are low.

(3) Since multiple arms are connected in series as open-loop links, the motor loads of each joint and the resulting inertia torque act on the tips, reducing the capacity of the motor and reducer that drive the arms. It becomes large, which is disadvantageous in terms of shape and economy.

(4) During motion, interference torque occurs between the arms, so a reduction gear with a larger capacity is required to absorb this.

(5) Although the structure has high conformability around the horizontal axis,
It is extremely difficult to feedback the force at the tip due to the backlash caused by the joint mouth, the crackle, etc., and it is unsuitable for general-purpose assembly work that involves force sensation.

(6) Poor compliance in vertical motion.

('7) Because of the reduction gear, it takes a lot of effort and time to teach the robot.

Therefore, it has many of the above-mentioned drawbacks, and there are limits to continuous speed, high precision, and miniaturization, which are highly demanded in the industrial world.

In addition, since there are many component devices (such as reduction gears) used and many rotating and sliding parts, lubrication is required, making it almost difficult to use in a clean environment or in a vacuum.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention is aimed at plane work that requires precision and high speed, eliminates the need for a reducer, enables direct teaching with a simple configuration, and is suitable for general-purpose assembly work (fine fine work) involving force sensation. adjustment,
The purpose of the present invention is to provide an industrial robot that can carry out inspection work, etc.), as well as transfer and assembly work in a clean environment or in a vacuum.

Structure of the Invention The present invention provides a first motor installed on a pace, a first arm directly attached to the output shaft, and a second arm connected at the other end of the first arm.
an arm; a third arm coupled at the other end of the second arm;
a closed-loop polygonal link arm consisting of a fourth arm coupled at the middle of the third arm; and a second prime mover directly coupled at the other end of the fourth arm; A pillar for connecting the second prime mover, a linear motor section consisting of a magnet, a magnet yoke, a coil bobbin, etc. at the other end of the third arm, a chuck at the tip, and a position detector for the first arm and the second arm; a bracket for connecting the second prime mover and the support; a means for adjusting and fixing the vertical position and the center of the second prime mover; and a means for rotatably fixing the relative position of the center of the second prime mover and the support; In addition, the closed loop polygonal link arm is composed of a weight that adjusts the center of mass of each arm and a shaft engagement part that changes the arm length, allowing high-speed operation for flat surface work.

High-precision position/force control possible, direct teaching possible,
It has many unique advantages such as high compliance, ease of changing the work area, and applicability to clean environments and work in vacuum.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a perspective view of the industrial robot in the first embodiment, and the third embodiment shows a perspective view of the industrial robot in the first embodiment. 4th. Figure 5 shows the front, side,
It shows a plane.

In Figures 2 to 5, 12 is a base that supports the whole;
13 is a first prime mover (hereinafter referred to as the first motor), 14 is an output shaft of the first motor, and 15 is a first motor attached directly to the output shaft.
The arm 016 is the other end of the first arm and is connected to the shaft 17. shown in FIG. Bearing 18a.

18b and a nut 19, the second arm is rotatably coupled, 20 is the other end of the second arm, as shown in FIG.
21. The third arm and 24 are rotatably connected by bearings 22a and 22b and a nut 23, and are a fourth arm. The fourth arm is located between the third arm and the shaft 2 shown in FIG.
6. Bearing 26a.

26b and a nut 27 for rotation. A second prime mover (hereinafter referred to as a second motor) 28 has an output shaft 29 and is directly connected to the other end of the fourth arm. 30 pillars integrally engaged with the base 1; 31 a placket for holding the first motor and the pillar; 32 a bladder 7l-133a, 33b for rotatably fixing the second motor and the pillar as a rotation axis of the pillar center metal. , 33c is the bracket 32
This is a set bolt that fixes the to the support. 34a, 34b
.

34c', 34d are adjustment screws for adjusting the vertical position of the second motor; 35a, 35b, 36G, 35d (not shown) are adjustment screws for adjusting the 1IQh center of the second motor; 36a;
, 36b, 36C, and 3ea are fixing bolts of the second motor. The above first to fourth arms constitute a quadrilateral link arm. 8th. Figure 9 shows the tip hand part, 3rd is a magnet yoke attached to the other end of the extension connecting the two rotation axes of the third arm, 38a and 38b are magnets, 39 is a coil bobbin, and 40 is a coil (see Figure 9). (not shown),
41. 42 is Nutonover, 43 is vertical position detector, 44
Reference numeral denotes a code plate constituting a vertical position detector, 45 a vertical guide bearing, and 46 a chuck incorporating a coil bobbin 39 and a solenoid (not shown) for detecting the vertical position. 4
8.49 is the first one attached to the plackets 31 and 32.
and a detector for detecting the absolute position of the output shaft of the second motor, and the relative position is detected by calculation.

Reference numerals 50 and 51 shown in FIG. 4 are weights detachably attached to the left and right sides of the intermediate shaft inside the third arm 20 to adjust the center of gravity position of the entire third arm.

The operation of the industrial robot y) configured as described above will be explained below. Generally, in the case of an industrial robot intended for flat work, arbitrary positioning, vertical movement of the tip, and opening/closing operation of a chuck that grips the target part are essential. In the industrial robot of this embodiment, the first and fourth arms are directly driven by the motors without a reduction gear by energizing the first motor, the second motor, and the tip near motor section and transmitting appropriate signals. An arbitrary tip position is determined by an articulated link arm connected to the second and third arms. Also, the linear motor section at the tip allows direct control of the vertical position and speed without using a reduction gear. The chuck is opened and closed by appropriately energizing a solenoid built into the chuck. In the case of this robot, a closed-loop link arm is used to determine the position and transmit force, but since it is a closed loop, in order to connect it to each bearing part without difficulty, it is necessary to connect the final connecting part, that is, the fourth link and the second motor. It is necessary to match the output shafts of the two. Adjustment screws 33, 34, 36 provided on the bracket 32 to achieve this
Adjust the arcing direction, vertical direction, and motor shaft center using the screwdrivers, and fix with the fixing bolt 36. Furthermore, it is generally known that in a horizontal articulated robot as shown in FIG. 1 which is connected in series, interference torque occurs between the arms.

Even in the arm configuration of a closed loop link system, there is generally an interference torque on the fourth arm due to the drive of the first arm, or conversely an interference torque on the first arm due to the drive of the fourth arm. This causes disturbances, resulting in deterioration of controllability and unnecessary increase in drive torque, but in the case of closed-loop links, it is known that this interference force can be reduced by appropriately selecting the center of mass of each arm and the arm length. . In this robot, in order to select these conditions, the center of mass can be moved using a weight on each arm, and the arm length can be easily changed by removing nano) 19, 23, 27 from each arm axis and replacing the arm. have the means to do so. Furthermore, in general robots, when the arm length is fixed,
Although it is quite difficult to change the working area, in the case of this robot, the first motor is fixed and the second motor can be rotated by adjusting the bolt 33 with the axis of the second motor as the rotation center. By adjusting the distance between the first motor and the second motor using this method, it is possible to easily change the work area of the robot without changing the pace attachment or the like. This rotationally fixed state is shown in FIG.

In addition, in the first embodiment, a closed loop link arm was constructed using the first to fourth arms, but additional arms were added,
A multi-joint link arm may also be configured.

Effects of the Invention As described above, the industrial robot of the present invention uses a prime mover that directly drives the arm without using a reduction gear, and transmits force through a closed-loop link arm mechanism, so that the motor load is reduced to the weight of the arm. is not added to the @ of the entire arm system.
In addition, there is no spring system normally included in reduction gears, which increases the inherent value of the arm system, and the acceleration/deceleration characteristics can be easily controlled, resulting in faster speeds. There is no backlash in the transmission system, and there is little play or loss, allowing for highly accurate positioning.The load situation at the end of the arm can be fed back directly to the motor, making it easy to control the force sense.A horizontal link is used and deceleration is achieved. Since it does not use a machine and is equipped with a position measuring device for the output arm, it is possible to teach robot work directly with almost no load on the robot tip, and it can directly drive the left and right and up and down directions. Therefore, compliance adjustment in both directions can be easily achieved by adjusting the control system servo rigidity of the drive motor. By appropriately varying the horizontal distance between the axes of the first and second motors, the work Because the area can be easily changed and the transmission mechanism is simple, there is less dirt and dust caused by lubrication and mass, which is a problem when using a reducer.
Being able to work in a clean environment or in a vacuum, etc.
It has many excellent features, and its practical effects are unparalleled.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional horizontal articulated robot, and FIG. 2 is a perspective view of an industrial robot according to a first embodiment of the present invention.
FIG. 3 is a front view of the same partial cross section, FIG. 4 is a side view of the same partial cross section, FIG. 6 is a plan view of the same, FIG. 6 is a cross sectional view of the shaft engaging portion of the second arm and the third arm, 7 is a sectional view of the shaft engaging portion of the third arm and the fourth arm, FIG. 8 is a partially sectional side view of the hand portion at the end of the third arm, FIG. FIG. 10 is a plan view of the robot when the work area is changed. 12... Pace, 13... First prime mover, 15°°. ...-first arm, 16...second arm, 20
...Third arm, 24...Fourth arm, 28...Second prime mover, 30...Strut, 3
1.32...Bracket, 37...Magnet, 38...Magnet yoke, 39.
... Coil bobbin, 40 ... Coil, 43
... Vertical position detector, 45 ... Vertical guide bearing, 4 ends ... Chuck, 48.49 ...
...Position detector, 50°51... Weight. Name of agent: Patent attorney Toshio Nakao and 1 other person
3 Figure 4 Figure 6 Figure 7 Figure 8

Claims (5)

[Claims] (1) A first prime mover installed on a base, a first arm attached directly to the output shaft of the first prime mover, a second arm rotatably attached to the other end of the first arm, and a first arm attached directly to the output shaft of the first prime mover. A closed loop consisting of a third arm rotatably coupled to the other end of the two arms, a rotation axis between the third arm, and a fourth arm having a rotation axis common to this rotation axis. A polygonal link arm, a second prime mover that is directly coupled to the other end of the fourth arm, and a support that connects the first prime mover and the second prime mover, and the first prime mover and the second prime mover are arranged above and below via the support. and an industrial robot in which the polygonal link arm is installed horizontally. (2) At the other end of the extension connecting the two rotation axes of the third arm, there is a linear motor section consisting of a magnet, a magnet yoke, a coil, a coil bobbin, and a bearing for vertically guiding the coil bobbin, a vertical position detector, and a coil bobbin. An industrial robot according to claim 1, comprising an integrally engaged chuck. (3) A detector is provided between the output shafts of the first prime mover and the second prime mover and the support that connects the first prime mover and the second prime mover to detect the relative position and absolute position of each. The industrial robot according to item 1. (4) A bracket that engages and holds the second prime mover and the support, a means for adjusting and fixing the top and bottom of the second prime mover and the center of the prime mover to the bracket, and a means for adjusting and fixing the second prime mover and the center of the prime mover to the bracket, and a means for adjusting and fixing the second prime mover and the center of the prime mover to the bracket, and a means for adjusting and fixing the second prime mover and the center of the prime mover to the bracket, and a means for adjusting and fixing the second prime mover and the center of the prime mover to the bracket. The industrial robot according to claim 1, further comprising means for rotatably fixing relative positions. (5) The industrial robot according to claim 1, which has a weight for adjusting the position of the center of mass of the first to fourth arms and a shaft engaging portion for detachably changing the arm length.