JPH025558B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot suitable for use in narrow spaces.

If robots are made smaller, they can be used in smaller spaces, but on the other hand, the robot's operating range becomes narrower, reducing the benefits of using the robot. For this reason,
Despite its small size, it is desired to have a wide operating range.

Generally, industrial robots are made by connecting several swivel arms or telescoping arms, but with the conventional robot structure, the operating area is substantially restricted due to the narrow working area. It is often not suitable for working in confined spaces.

The present invention proposes a small industrial robot that is installed inside a box-shaped workpiece and is suitable for applications such as performing work on the inner surface of the workpiece.

Another object of the present invention is to propose an industrial robot having a structure without singularities.

The robot of the present invention includes a linearly movable actuation mechanism in which a movable member moves linearly and telescopically relative to a holding member that holds the movable member, and a first swing arm whose base is pivotally supported at the upper end of the movable member. The base is pivotally supported at the tip of the first pivot arm, and the tip is provided with a second pivot arm equipped with a tool, and the movable direction of the movable member and the center line of the pivot axis of the first pivot arm are connected to the second pivot arm. In cases where the center lines of the pivot axes of the pivot arms are parallel to each other, the dimension from the pivot point of the second pivot arm relative to the first pivot arm to the tip of the pivot arm is defined as the dimension from the pivot point of the first pivot arm relative to the movable member to the second pivot arm. It is characterized by being longer than the dimension up to the shaft fulcrum.

The embodiment of the present invention shown in FIG. 1 will be described below. A telescopic operating mechanism 10 is disposed on a mounting seat 100 of the robot. This operating mechanism 10 includes a holding member 11 fixed to a mounting seat 100, and a movable member 13 that is held by this holding member and moves linearly. This movable member 13 is connected to the holding member 11
It is configured to move from almost one end to the other. 12 is a screw shaft for moving the movable member 13 up and down, and 19 is its rotational drive source.

The base of the first swing arm 21 is pivotally supported by the movable member 13, and this is configured to be rotationally driven by a rotational drive source 22 about the pivot support. The base of the second swing arm 31 is pivotally supported at the tip of the first swing arm 21, and is configured to be rotationally driven around the pivot support by a rotational drive source 32.

The movable direction of the movable member 13 and the first swing arm 2
The center line of the pivot axis in 1 and the second pivot arm 3
The center lines of the pivot axes in No. 1 are parallel to each other.

The dimension from the pivot point of the second pivot arm 31 with respect to the first pivot arm 21 to the tip is configured to be longer than the dimension from the pivot point of the first pivot arm 21 with respect to the movable member 13 to the pivot point of the second pivot arm 31. There is.

The relationship between the rotation plane of the first rotation arm 21 and the rotation plane of the second rotation arm 31 is configured such that they are shifted in the direction of their rotation axes, and there is no movement in the rotation plane of the second rotation arm 31. The mechanism 10 is configured so that it cannot be inserted.

A tool 50 such as a welding torch is attached to the tip of the second swing arm 31 via the wrist 40. The wrist 40 has two rotation axes 4 perpendicular to each other.
1,42. Reference numeral 43 is a drive source for the rotating shaft 41, and its power is transmitted through a chain in the second swing arm 31, which is not shown in the drawings. 44 is a driving source for rotation 42.

In the structure configured as above, the tool 50
When controlling the height direction position of the rotary drive source 1
9 to rotate the screw shaft and move the movable member 13
move up and down.

In addition, when controlling the position of the tool 50 on the horizontal plane, either one or both of the rotational drive source 22 and 32 is controlled, and either the first swing arm 21 or the second swing arm 31 is controlled. drive one or both.

Now, in the present invention, the second swing arm 31 is configured to be longer than the first swing arm 21, and the effects thereof will be explained.

Consider the case where A is the work surface of work B, and welding or painting is performed on it.

The robot installation position substantially coincides with the rotation center position C of the first rotation arm 21, but since this is a narrow place blocked by an obstacle D, the robot is installed close to the work surface A. Since a space is required around the installation position for erecting the operating mechanism 10, the turning center position C cannot be brought close to the obstacle D.

In any case, the first and second swing arms 21,
31, work surfaces A1, A2, A3, A
The work progresses while tracing the tools 50 in order as in 4 and A5. The solid lines indicate the movements of the first and second swing arms 21 and 31 at this time. If you simply want to position each point from A1 to A5, the lengths of the first and second swing arms should be in the opposite relationship to the present invention, and the first swing arm should be longer than the second swing arm. It seems to be equally effective. The wavy lines indicate the first swing arm and the second
This figure shows the situation when the length is longer than that of the swing arm, and in this case, the first and second swing arms 2
The lengths 10 and 310 correspond to the lengths of the second and first swing arms 31 and 21, respectively. In the case of the solid line, the second swing arm is longer as described above, but in the case of the broken line, the relationship is reversed, and the first swing arm 210 is longer. Even if the first and second swing arms 210 and 310 shown by the dotted lines are employed, it is possible to position at point A1. However, when attempting to position at other points A2 to A5, the tip of the first swing arm 210 hits the work surface A, making it impossible to work on that part. If the first swing arm 210 is moved to the right in the drawing at point C, it is possible to work at points A2 to A5, but it is not possible to move the first swing arm 210 to the right because the obstacle D is in the way. In other words, with the configuration shown by the wavy lines, it is not possible to perform work over the entire range of A1 to A5. In contrast, according to the solid line, that is, according to the present invention, work can be performed over the entire range A1 to A5 with the tip of the first swing arm 21 located on the right side of point C.

The length of the first swing arm 21 is the length of the second swing arm 3.
If the length is different from 1, an unreachable region is created in a portion surrounded by a circle centered on the pivot point C of the first pivot arm, with the difference in length as the radius. On the other hand, if the lengths of both arms 21, 31 are made equal, no such unreachable region occurs. However, in the present invention, having this unreachable area is very advantageous in controlling the robot. This will be explained below using FIG. 4.

When moving the tip of the tool 50 held by the robot (control target point) from P1 to P2 according to a pre-stored command, in addition to the coordinate position data of P1 and P2, the The wrist posture data at point P2 and the wrist posture data at point P2 are stored as teaching data.

During playback control, read those data, first find the number of interpolations required to move from point P1 to P2 (four times in the case of Figure 4), and change evenly with this number of interpolations to get the coordinate P1. A wrist control command for transitioning from the wrist posture at point P2 to the wrist posture at point P2 is determined.

Next, from this wrist posture data, the second rotating arm 3
Find the position coordinates pa, pb, pc, pd, pe to which the tip of 1 must move during each interpolation, and then set the driving source to satisfy these position coordinates pa, pb, pc, pd, pe. The commands given to 19, 22, and 32 are obtained by coordinate transformation. There are many documents regarding these calculation steps. As an example, JP-A-55
-118107 and Japanese Patent Publication No. 61-2964.

The first swing arm 21 and the second swing arm 31 can be positioned at position coordinates pa, pb, pc, pd, and pe in two different postures, for example, as shown with pa as a representative. Therefore, one posture is adopted and the other posture is discarded, but the one to be adopted selects the one whose posture data has a smaller difference from the previous interpolation. In this way, it is possible to position the general position, but any one of the position coordinates pa, pb, pc, pd, and pe coincides with the rotation center C of the first rotation arm 21 (in the figure, one point coincides with the rotation center C of the first rotation arm 21). However, there are an infinite number of postures in which the object can be positioned at that position, and as a result, positioning becomes impossible in terms of control. Such a position is called a singularity.

In this way, when the lengths of the first swing arm 21 and the second swing arm 31 are the same, a singularity occurs, but
In the present invention, since the singular point falls within the unreachable region, there is no need to consider the problem of the singular point.

Furthermore, since this unreachable area is originally inside the mounting seat 100 of the robot, there is no need to perform work inside such an area. Therefore, even if there is an unreachable area surrounding the pivot center of the first pivot arm, this does not pose any problem.

Therefore, the first swing arm 21 and the second swing arm 3
Rather than making the lengths the same, it is more desirable to have different lengths as in the present invention. Furthermore, by making the second swing arm 31 longer than the first swing arm 21 and setting the length appropriately, there is less fear that the tool 50 will collide with the first swing arm 21 during the swing.

As is clear from the above description, according to the present invention, the length of the second swing arm is longer than the length of the first swing arm. It can be installed close to the turning trajectory of the tip, and has the advantage that there is no need to consider the problem of singular points during control.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the industrial robot according to the present invention, Fig. 2 is a perspective view showing the state when it is reduced, Fig. 3 is an explanatory diagram of its operation, and Fig. 4 is an explanation of the operation of the robot. It is a diagram. 10 is an operating mechanism, 11 is a holding member, 13 is a movable member, 21 is a first swing arm, 31 is a second swing arm, and 50 is a tool.

Claims (1)

[Claims] 1. A linearly movable operating mechanism in which a movable member moves linearly and telescopically relative to a holding member that holds it; a first swing arm whose base is pivotally supported at the upper end of the movable member; The base portion is pivotally supported at the tip of the pivot arm, and the tip is provided with a second pivot arm having a tool, and the movable direction of the movable member, the center line of the pivot axis of the first pivot arm, and the second pivot arm are provided. In the case where the center lines of the pivot axes of the pivot arms are parallel to each other, the dimension from the pivot point of the second pivot arm to the tip of the pivot arm relative to the movable member is determined from the pivot point of the first pivot arm relative to the movable member. An industrial robot characterized in that the length of the second swing arm is longer than the pivot point of the second swing arm.