JPS5935755B2 - robot wrist device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wrist device for a robot used for industrial purposes, etc., and in particular, it is capable of always controlling the final posture of a working tool by controlling one axis, and can handle all work surfaces. Shiru 3
This invention relates to a degree-of-freedom robot wrist device.

Conventionally, robot wrists imitate the functions of the ideal human wrist, with degrees of freedom such as bending, rotating, and rotating only the fingers in addition to grasping, as shown in Figure 1a. -c is a typical example.

That is, in this case, the hand part 1 centered on the β axis as shown in FIG.
It has a bending function, a rotation function of the entire wrist around the α-axis as shown in b in the same figure, and a function of rotating only the hand 1 around the axis of the hand 1 itself and the γ-axis as shown in c of the same figure. The skeleton of this hand is shown in Figure 2 as a mechanical diagram.
By the way, when a grinder is attached to the wrist of a conventional robot as described above, the state is as shown in FIG. 3.

Here, the grinder applies the cutting point 4 on the grindstone 3, which is located directly opposite to the grindstone cover 2, to the cutting point of the workpiece, and also maintains an appropriate angle between the workpiece 5 and the grindstone 3, as shown in FIG. Must work in a posture that maintains θ. Therefore, for example, when removing cast flash 1 in the α-axis direction on the lower surface 6 as shown in FIG. 4, the attitude of the grinding wheel (controlling the angle θ) must be adjusted by turning around the β-axis. At the same time, the grinder 8 may be moved forward. Similarly, the attitude of the grinder can be controlled only by turning the β-axis regarding the cast burr 10 on the front face 9 in the vertical direction and the cast burr 2 on the upper surface 11 in the α-axis direction. However, regarding the grinding wheel 3 or 14 on the bottom surface 6 or the soil surface 11, which is perpendicular to the plane of the paper, and the casting wheel 5, which is vertically on the right side, the grinding wheel rotates around the β axis. Attitude control is not possible, and we must rely exclusively on attitude control by turning around the α-axis. In this way, if the axis that controls the final posture of a work tool such as a grindstone differs depending on the direction of work or work location, it is dangerous because the worker may operate the wrong axis. At the same time, calculations for calculating the positioning and posture of the work tool become complicated, increasing the risk of operational errors.
Such a risk increases to the extent that it becomes almost difficult to follow when the position of the object to be worked on, such as casting flash, changes in three dimensions. The cause of such inconvenience will be explained with reference to the mechanism diagram in Fig. 2.

When the α-axis is rotated in the state shown in a of the same figure, since the axis of the work implement A and the α-axis coincide with each other, the work implement A rotates around the α-axis. On the other hand, when the β-axis is operated to rotate the α-axis in a state where the axis of the work tool A and the α-axis are perpendicular to each other as shown in FIG. 2B, the work and the tool A revolve around the α-axis. In this way, in the illustrated mechanism, the α-axis can be said to have two abilities: the ability to rotate on its axis and the ability to revolve around the working tool.

However, the β-axis in the figure can only cause the working tool to revolve around the same axis, and the γ-axis only has the ability to cause the working tool to rotate about the γ-axis. As described above, since the β-axis and the γ-axis only have the function of revolution or rotation, the freedom of controlling the posture of the work tool is impaired as a result. The present invention has been made in view of the above points, and is an improvement on the conventional robot wrist device having three rotational degrees of freedom, in which each rotational axis intersects at one point, and Two of the axes can cause the work tool to rotate and revolve, and the remaining one rotation axis can only cause the work tool to revolve, and the axis to which the work tool is attached can only perform the above-mentioned revolution. It is characterized by a configuration in which it is paralyzed with a rotational axis, and the lever allows the posture of the tool to be controlled during movement by always operating one axis that can only revolve as described above. The purpose is to

Next, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings starting from FIG.

Here, FIG. 5 is a mechanical diagram showing only the schematic framework of a robot wrist device that is an embodiment of the present invention, and FIG. 6 is a mechanical diagram showing the same device as a cast burring robot equipped with a grinder for cast burring. Q is a side sectional view of the entire device when applied to the wrist, Figure T is a side sectional view showing details of the wrist drive unit that can be used in the device, and Figure 8 is a wrist section that can be used in the device. FIG. 9 is a side sectional view showing the details of the casting deburring robot, and FIG. 9 is a side view showing the operating state of the casting deburring robot. First, the basic outline of the present invention will be explained using FIGS. 5A and 5B.

In the figure, three rotational axes, α-axis, β-axis, and γ-axis, intersect at the center point O, and the α-axis is orthogonal to the α-axis via a cantilever arm 16 integrally connected thereto. It is connected to the γ axis, and the γ axis and β axis are . They are always connected orthogonally.
Therefore, the rotation of the α axis causes the β and γ axes to rotate around the center point O, so that the work tool A rotates at α as shown in a in the same figure.
If it is on the γ-axis, the rotation of the α-axis causes the tool to rotate, and if the tool A is on the γ-axis as shown in Figure b, then the rotation of the α-axis causes the revolution of the tool. Three axes are connected to invite you. Further, as mentioned above, the γ-axis is perpendicular to the β-axis, and is fixed to the double-held arm IT which is swingable with respect to the cantilever arm 16 and rotatable with respect to the β-axis, and the rotation of the γ-axis is The β-axis is rotated around the center point o, and the rotation of the γ-axis in the state shown in figure a causes the work implement A to revolve around the γ-axis, and the rotation of the γ-axis in the state shown in figure b causes the work tool to rotate. It is configured to cause rotation of A.

On the other hand, the β-axis is rotatably supported by the above-mentioned both-holding arm IT, and a working tool is integrated with the both-holding arm 18 fixed to this β-axis and attached to a shaft 1δ perpendicular to the β-axis. A, and the relationship with other axes is determined so that rotation 0 of the γ-axis only causes the work tool to revolve around the γ-axis. Next, regarding an embodiment in which the present invention is applied to the wrist of a cast deburring robot, with reference to the attached drawings starting from Fig. 6,
It will be explained in more detail.

In these figures, the axis passing through the center point O and perpendicular to the plane of the paper is the β axis, the horizontal axis along the plane of the paper is the γ axis, and the vertical axis is the α axis. The α-axis drive motor 19 is located on the α-axis, and the drive frame 22 is supported by a bearing 21 via a reduction gear 20.
is connected to. The grinder G, which is a working tool, is β
It is held by a tool holder 23 mounted on the shaft, and this tool holder 23 swings as the β axis rotates. A motor 24 for driving the β-axis and a motor 25 for driving the γ-axis are fixed to the drive frame 22. The β-axis motor 24 is driven by a bevel gear 28 by a drive shaft 2T via a reducer 26.
The bevel gear 28 meshes with a bevel gear 31 provided on a shaft 30 coaxially fixed to the spur gear 29.

A shaft 33 of the body coaxial with the spur gear 32 meshing with the spur gear 29 is
A hollow shaft 35 supported by a bearing 34 is supported by a bearing 36, and a bevel gear 3T is coaxially fixed to the tip of the hollow shaft 35. It meshes with a bevel gear 39 provided coaxially with a holder drive shaft 38 to which the holder 23 is attached. The γ-axis motor 25 is connected to a bevel gear 42 by a drive shaft 41 via a reducer 40.
A bevel gear 43 is connected to the bevel gear and meshes with this bevel gear.
A hollow shaft 44 coaxially mounted is supported by a bearing 45, and the aforementioned shaft 30 passes through the hollow portion thereof.

A spur gear 46 coaxially fixed to the end of the hollow shaft 44 meshes with a spur gear 4T coaxially provided to the end of the hollow shaft 35. A wrist case 48 is attached to the other end of the hollow shaft 35.
The holder drive shaft 38 is rotatably attached to the wrist case 48. 49 and 5
0 is a detector for the rotational position of the β-axis and the γ-axis, and although not shown, the α-axis motor 19 is also provided with a detector for the rotational position of the α-axis.

One or two such detectors are required for each motor! Located around the area. Next, the operation will be explained.

When the motor 19 is driven, the drive frame 22 rotates, and the motors 24 and 25 attached to the drive frame 22, the wrist case 48 connected thereto, and the tool holder 23 rotate integrally around the α axis. Therefore, in the state shown in FIG. 6, the grinder G also rotates around the α axis, but if the motor 19 is driven with the β axis rotated 90 degrees, the grinder G rotates around the α axis.
revolve around an axis. On the other hand, when the other motors are stopped and the motor 25 is driven, the rotation of the bevel gear 42 is transmitted to the bevel gear 43, spur gears 46, 4T, and the wrist case 48 integrated with the hollow shaft 35 rotates around the γ axis. do. Therefore, the grinder G revolves around the γ-axis in the state shown in FIG. 6, and rotates around the γ-axis when the grinder G is rotated 90 degrees around the β-axis. When the motor 24 is further driven, the rotation of the bevel gear 28 is transmitted to the bevel gear 31 and the spur gears 29 and 32, and further to the bevel gear 3 via the shaft 33.
Since T, 39 rotates, the holder drive shaft 38 rotates,
The tool holder 23 and the grinder G attached thereto swing (revolution) around the holder drive shaft 38, that is, the β axis. Since the grinder G is installed on the shaft δ′ attached at right angles to the holder drive shaft 38, the holder drive shaft 38
The rotation of 8 only causes the grinder G to revolve and cannot rotate. The manner in which cast burrs are removed using the wrist device of such a cast burr removal robot will be explained with reference to FIG. 9.

In the figure, reference numeral 51 indicates a drive section housing the motors 19, 24, 25, drive frame 22, etc., and G indicates a grinder, with α-axis, β-axis, γ-axis
The axes are orthogonal at the center point O. First, the horizontal cast burrs 53 on the lower surface 52 facing the grinder G, and the vertical cast burrs 56 and 5T on the right side 54 and left side 55 are removed by rotating only the β axis in the state shown in the figure. This allows you to maintain the correct posture of the grinder. Also, the lower surface 52
Regarding the casting burrs 58 perpendicular to the plane of the paper above and the casting burrs 59 in the vertical direction on the front and rear surfaces of the plane of the paper, by rotating the α-axis by 90 degrees, the posture of the grinder can be adjusted by operating only the β-axis. Control is possible. Furthermore, regarding cast burrs in the left and right direction on the front and rear surfaces, the posture of the grinder can be easily maintained by turning the grinder by 90 degrees around the γ axis and then turning around the β axis. Finally, regarding the cast burrs 60 and 61 perpendicular to the plane of the paper on the left and right side walls 54 and 55, the α axis is rotated 90 degrees, and the γ
If the shaft is rotated by 90 degrees, the proper attitude of the grinder G can be obtained by only turning around the β axis. In addition to the above-mentioned grinder, devices that require posture control include chippers, hammers, and spray guns for painting, and as described above, the present invention is designed to It is ideal as a wrist device for robots that operate tools, and since the posture of tools, etc. can be adjusted with one axis during work, no matter which surface the robot wrist faces, there is no risk of misplacing the operating axis. Since the calculation of the position of the tool is extremely simple, it is possible to easily follow a work object that changes continuously in three dimensions, and the operability and accuracy are significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the motion of a conventional robot wrist, FIG. 2 is a mechanical diagram showing only the skeleton of the wrist, and FIG. 3 is a perspective view showing a state in which a grinder is attached to the wrist. Fig. 4 is a side view showing the cast deburring operation using the same wrist, Fig. 5 is a mechanical diagram showing the framework of the wrist device which is an embodiment of the present invention, and Fig. 6 is a side view showing the cast deburring work using the same wrist. A detailed side sectional view of the drive section and wrist section of the device shown in FIG. 6, and FIG.
The figure is a side view showing the operating state of the casting deburring robot. Explanation of symbols, α axis, β axis, γ axis...rotation axis, O
... Center point, A ... Working tool, G ...
... Grinder, δ ... Axis, 19, 24, 2
5... Motor, 22... Drive frame, 35
, 44...Hollow shaft, 28, 31, 3T, 39,
42, 43... Bevel gear, 29, 32, 46,
4T...Spur gear, 38...Holder drive shaft, 23...Tool holder, 48...Wrist case.

Claims (1)

[Claims] 1. In a robot wrist device with three rotational degrees of freedom, two rotation axes that cause the work tool to rotate and revolve;
and one rotation axis that allows the working tool to only revolve, the three rotating axes intersect with each other at one point, and the working tool is mounted on an axis that is orthogonal to the rotating axis that allows only the revolution. A robot wrist device characterized by: