JPH042399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a joint device whose shaft end moves on a spherical surface, and is used for rotational driving of robot joints, parabolic antennas, and the like.

(Prior art and its problems) Conventionally, in order for the shaft end to move along an arbitrary trajectory on a spherical surface and maintain its posture, as shown in FIG. 14, rotation A of the first shaft 1, Rotation B of the second axis 2,
Generally, the rotation C of the third shaft 3 and the rotation C of the third shaft 3 are realized by combining the rotation C and the rotation C of the third shaft 3 using a drive device such as a motor. That is, the first axis 1 in FIG.
By the rotations A and B of the second shaft 2, the shaft end of the third shaft 3 was made to move in an arbitrary trajectory on the spherical surface.

However, in order to maintain the posture of the shaft end of the third shaft 3, it was necessary to rotate the third shaft 3 as well. In order to show this relationship, the third axis 3 and the second axis 2 are not rotated, only the first axis 1 is rotated, and the movement of the mark F attached to the tip of the third axis 3 is observed from the direction above the first axis 1. The state as seen is shown in Fig. 15. So the dotted line is the first
The state of the mark F and the trajectory F' of the mark F when the shaft 1 rotates is shown. Note that for rotation of only the second axis 2, the direction of the mark F does not change as shown in FIG. 15 for rotation until the second axis 2 is on a straight line with respect to the first axis 1. In order to maintain the posture of the mark F as shown in FIG. 16 with respect to the rotation of the first axis 1, it was necessary to rotate the third axis 3 as well.

Therefore, in such a conventional structure, 3
A rotating shaft with various degrees of freedom is required, and a number of drive devices such as motors are also required according to the degrees of freedom of the rotating shaft.The rotation angle of each shaft is determined based on the disadvantage that the device becomes large and the position and orientation of the shaft end. This has the disadvantage that the coordinate exchange becomes complicated.

(Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks, and to provide a system in which the shaft end moves in an arbitrary trajectory on a spherical surface in two degrees of freedom, and maintains the posture of the shaft end. To provide a joint device that has a simple structure, is small in size, and can easily perform joint coordinate transformation.

(Structure of the Invention) The first invention of the present application provides a first invention that rotates so as to slide on each other on sliding surfaces made of planes that form a certain angle with respect to each other around their intersection points.
and a second shaft, and a third shaft provided on an extension of the first shaft and rotationally driving the first shaft;
A fourth shaft is provided on an extension of the second shaft and rotates the second shaft, and the first shaft is held so as to be rotatable with respect to the third shaft. , the second shaft is held so as to be rotatable relative to the fourth shaft, and the second shaft of the annular connecting means is connected to the annular connecting means installed so that the center of the sliding surface coincides with the center of the fourth shaft. The third shaft is connected to the annular connecting means by a first fixing means mounted for rotation about an axis having a diameter of 1, while the third shaft is orthogonal to the first diameter and is connected to the annular connecting means. a second rotatably mounted about an axis that is the second diameter of the connecting means;
The joint device is characterized in that the fourth shaft is connected to the annular connecting means by the fixing means.

A second invention of the present application provides first and second shafts that rotate so as to slide on each other on a sliding surface formed of a plane that forms a certain angle a with respect to each other around their intersection points; a third axis that is provided on an extension of the axis and rotationally drives the first axis; and a fourth axis that is provided on an extension of the second axis and rotationally drives the second axis. and the first
The shaft is held rotatably relative to the third shaft, the second shaft is held rotatably relative to the fourth shaft, and the center of the sliding surface and the The third shaft is connected to the annular connecting means by means of a first fixing means mounted so as to be rotatable about an axis having a first diameter of the annular connecting means with respect to the annular connecting means arranged so that the centers coincide with each other. said fourth axis by means of second fixing means mounted so as to be rotatable about an axis which is connected to said first diameter and which is orthogonal to said first diameter and which is a second diameter of said annular connecting means; is connected to the annular connecting means, the angle between the extension line of the second axis and the first axis is an intersection angle g, passing through the intersection of the first axis and the second axis, and Said second
When the axis of is set as the z-axis, the angle formed by the projection of the first axis on the x-y plane perpendicular thereto with the x-axis is the azimuth angle b, and the intersection angle g and the azimuth angle b are input, The common angle X for rotationally driving the first and second axes from the intersection angle input ^is calculated by the formula ))) A circuit that obtains the rotational drive output for the first axis by adding the azimuth angle to the obtained common angle, and a circuit that obtains the rotational drive output for the first axis by subtracting the azimuth angle from the obtained common angle. The joint device is characterized by comprising a circuit that obtains a rotational drive output for the second axis.

(Detailed Description of Configuration) In the joint device of the present invention, the fourth axis is determined depending on the length of the first and third two axes and the angle of the sliding plate with respect to the first axis and the second axis. Within a spherical motion range determined by An arbitrary trajectory on a spherical surface with a radius of .times..times..times..times..times..times..times..times..times..times..times..times..times..degree. That is, the position of the shaft end on the spherical surface, in other words, the angle and direction at which the first and third axes intersect with the second and fourth axes is the rotation angle of the first and second axes. It can be decided depending on.

(Example) The present invention will be described below based on an example with reference to the drawings.

FIG. 2 is a diagram for explaining the principle of the present invention. Swing plates 40 and 50 are attached to one shaft end of each of the two rotating shafts 4 and 5 at a fixed angle. FIG. 3 is a side view with a part of FIG. 2 in cross section, and is a diagram for explaining the operation. The sliding plates 40 and 50 are connected by a bearing 6 centered at the intersection P of the center lines 4C and 5C of the two rotating shafts 4 and 5. Further, in the figure, the state of the rotating shaft 4' and the center line 4'C when the rotating shaft 4 rotates is shown by a two-dot chain line. As is clear from FIG. 3, since the shear plates 40, 50 have an angle a with respect to the rotating shafts 4, 5, the center of the rotating shafts is determined by the rotation angle of each rotating shaft 4, 5. The intersection angle where the lines 4C and 5C intersect and the azimuth angle, which is the direction in which the rotation axis 4 is tilted, change.

FIG. 4 is a side view of a mechanism section showing an embodiment of the present invention. Referring to FIG. 4, this mechanism section includes sliding plates 40 that constitute sliding surfaces made of planes that form a constant angle with respect to each other with their intersection points as centers.
and 50, a rotary shaft 4 constituting a first shaft and a rotary shaft 5 constituting a second shaft, which rotate so as to slide on each other by the sliding plate, and a rotary shaft 5 constituting a second shaft, which is on an extension of the first shaft. A motor 7 constituting a third shaft that is provided and rotationally drives the rotary shaft 4 that constitutes the first shaft, and a rotary shaft that is provided on an extension of the second shaft and constitutes the second shaft. The motor 8 constitutes a fourth shaft that rotates the motor 5. Said first
The shaft is held so as to be rotatable with respect to the motor 7 constituting the third shaft using an output shaft 70, and similarly, the second shaft is held so as to be rotatable with respect to the motor 7 constituting the third shaft using an output shaft 80. It is held so as to be rotatable with respect to the constituent motor 8.

Further, an annular connecting means 9A is prepared so that the center of the sliding surface coincides with the center thereof, and a shaft 9 having a first diameter of the annular means 9A is prepared.
a first fixing means 9B mounted so as to be rotatable around the annular means 9A; A second fixing means 9C is provided. In the mechanism according to the present invention, the motor 7 constituting the third shaft is attached to the first fixing means 9B and rotates around the shaft 91 having the first diameter with respect to the annular connecting means 9A. Fixed to make it possible. Similarly, by attaching the motor 8 constituting the fourth shaft to the second fixing means 9C, the motor 8 is connected to the annular connecting means 9A.
It is fixed so as to be rotatable around an axis 92 having a diameter of .

The annular connecting means 9A and the first and second fixing means 9B, 9C have a structure similar to a universal joint conventionally used in various fields, and will hereinafter be referred to as the universal joint 9. do.

Now, when the output shafts 70, 80 of the motors 7, 8 are rotated, as shown in FIG.
50, on a spherical surface within the spherical motion range 10 centered on the intersection point P of the center lines of the rotating shafts 4 and 5 and with the radius equal to the sum of the length of the rotating shaft 4 and the length of the motor 7. can move at a speed determined by the rotational speed of the two rotating shafts 4 and 5, drawing a trajectory determined by the rotation angle.

Next, paying attention only to the tip of the motor 7, the rotating shaft 5 in FIG. 3 is erected vertically, and the x, y, z 3 axis is centered at the intersection point P shown in FIG. 6, and the Z axis is vertical. Assume that there is a rotation axis 4 in a dimensional coordinate system. Then, the direction of the sliding plate 50 is determined so that it will be in the state shown in FIG. 3 when viewed from the direction of the coordinate axis x.
When the motors 7 and 8 are rotated by the same number of rotations so that the rotation shafts 4 and 5 are rotated in the opposite direction when the rotation shaft 4 is vertical, the tip of the motor 7 always follows the trajectory 4 on the x-axis.
Draw 1. Furthermore, assuming that the tip of the motor 7 is tilted at a certain angle, when the rotating shafts 4, 5 are rotated in the same direction, a trajectory 42 centered on the z-axis is always drawn. This is a trajectory 51 of the tip of the motor 7 when only the rotating shaft 5 is rotated as shown in FIG. 7, and a trajectory 52 of the tip of the motor 7 when only the rotating shaft 4 is rotated as shown in FIG. (This locus 52 is symmetrical with the locus 51 in FIG. 7 in the xz plane.) This can be realized by a combination of the following.

Therefore, Fig. 9 shows a state in which the tip of the rotating shaft 4 (hereinafter, the same meaning as the tip of the motor 7) is tilted on the x-z plane by g degrees (the azimuth b of the rotating shaft 4 in this state is 0).
shall be. ) is shown. At this time, the tip of the rotating shaft 4 is z
Move from point P ₀ to point P ₂ on the axis. This operation consists of the rotation of only the rotating shaft 5 and the rotating shaft 4 shown in FIG.
5 can be broken down into the motion of rotating the same amount in the same direction. FIG. 10 shows the state of the locus of the tip of the rotary shaft 4 when it is divided into two movements in this way. As shown in Figure 7, the tip of the rotating shaft 4 moves from point P ₀ to point P ₁ by rotating only the rotating shaft 5, and rotates the rotating shafts 4 and 5 in opposite directions by a common rotation angle x degrees, z. When rotated around the axis, it moves to the same point P ₂ as in Figure 9. This allows the tip of the rotating shaft 4 to be
It can be seen that the rotation angle of the rotation shaft 4 for moving from P ₁ to point P ₂ is the rotation angle of the rotation shafts 4 and 5 for moving the tip of the rotation shaft 4 from point P ₀ to point P ₂ .

This means that the tip of the rotating shaft 4 is located at point P ₀ , point P ₁ , and point P ₂
This can be seen because the rotating shaft 4 rotates only when moving from point _P1 to point _P2 .

Therefore, in Fig. 11, point P ₃ is located from point P ₂ to z
The intersection of the perpendicular lines drawn to the axis, point P ₄ , is the intersection of the line drawn parallel to the y-axis from point P ₃ and the locus 42, point P ₅
is the point where _the line P ₃ -P ₄ intersects with a perpendicular drawn from point P ₂ to the center line 51C of the locus 51 shown in FIG. -P ₂ (corresponding to the rotation axis 4) and the z-axis intersect angle is g.

FIG. 12 shows the inside of the locus 42 when FIG. 11 is viewed from the z-axis direction. At this time, the line P ₂ − P ₃ and the line P ₁
-P ₅ are parallel, and lines P ₂ -P ₃ and P ₃ -P ₄ are at right angles. Therefore, the angle formed by point P ₁ , point P ₃ , and point P ₂ x
is the same as the angle formed by point P ₃ , point P ₁ , and point P ₅ . line
Let P ₂ - P ₃ be a line segment rg and line P ₃ - _{P 5} be a line segment rx.
Therefore, the angle x is x = sin ^-1 (rx/rg) The line segment rg is the radius of the locus 42, and the line segment P-P ₀ is R
Then, rg=Rsin(g) Next, as shown in Figure 13, two types of triangles (P-
P ₀ - P ₆ and P - P ₃ - P ₄ ), the line segment rx is rx = (R - Rcos(g)) / tan (90° - a) The angle 90° - a is the point P ₀ , point P, and point P ₆ form the third angle.
An angle of 90° between the rotating shaft 4 and the sliding plate 40 shown in the figure.
-corresponds to a. Therefore, x=sin ^-1 ((1-cos(g))/(sin(g)tan(90°-
a))) When the rotating shaft 4 is rotated x degrees and the rotating shaft 5 is rotated -x degrees, the tip of the rotating shaft 4 moves from point P ₀ to point P ₂ .

Furthermore, the rotating shafts 4 and 5 are rotated in the same direction by the same arbitrary azimuth b, and the tip of the rotating shaft 4 is
If it is rotated by the azimuth b around the z-axis from the position shown in the figure, the rotation angle M1 of the rotation axis 5 and the rotation axis 4
The rotation angle M2 is M1 = -X+b M2 = Can perform the following actions.

FIG. 1 is a block diagram of an electric circuit according to an embodiment of the present invention, in which rotation angles M1 and M2 are determined from intersection angle g and azimuth angle b based on the above-mentioned formula. In the figure, a circuit 200 is a circuit that calculates a common angle x from an intersection angle g, and a circuit 300 is a circuit that calculates rotation angles M1 and M2 by adding and subtracting a common angle x and an azimuth b. be. The circuit 100 is a sin(g) calculation circuit that calculates the sine of the intersection angle g, 110 is a tan(a) calculation circuit that calculates the tangent of the angle a, 120 is a 1-cos(g) calculation circuit, and 130 is the circuit 100. 140 is a multiplication circuit that calculates the product of the data from the circuit 110 and 140 is a division circuit that divides the data from the circuit 120 by the data from the circuit 130; 150
160 is a calculation circuit for calculating the arcsin of data from the circuit 140, and 160 is a circuit 15.
An addition circuit adds the data from 0 to the azimuth b, and 170 is a subtraction circuit that subtracts the data from the circuit 150 from the azimuth b. Said circuits 100 to 170
can be easily realized using a commercially available logic integrated circuit or software on a microprocessor, and if high speed is required, a table exchange method can also be used.

(Effect of the invention) As explained above, the joint device of the present invention has a second
The first and third axes can be tilted at any intersection angle and azimuth with respect to the fourth axis, and the attitude of the end of the third axis can always be kept constant; There is also an effect that joint coordinate transformation for determining rotation angles of the first and second axes with respect to the third or fourth axis corresponding to the azimuth angle can be easily obtained.

The joint device described in detail above can take full advantage of its features when applied to a robot joint, a rotary drive device for a parabolic antenna, and the like. When applied to a robot joint, the drive motor can be built into the link part constituting the robot body, making it possible to construct a robot arm that has no protrusions and is suitable for movement in narrow areas. When applied to the rotational drive of a parabolic antenna, the azimuth angle indicating the direction in the horizontal plane and the elevation angle indicating the direction in the vertical plane are the azimuth angle b and the intersection angle used in the above explanation as a coordinate system that determines the direction of wave transmission and reception of the antenna. g, and the antenna can be driven in a desired direction with a simple control device configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electric circuit according to an embodiment of the present invention, and FIG. 2 is a perspective view of rotating shafts 4, 5 and sliding plates 40, 50 for explaining the principle of the present invention.
FIG. 3 is a side view of FIG. 2, and FIG. 4 is a side view of a mechanical section of an embodiment of the present invention. 5 is a diagram showing the operation of the mechanism shown in FIG. 4, and FIG. 6 is a diagram showing the operation of the motor 7 shown in FIG. 4.
Figure 7 is a diagram showing the trajectory of the tip of the motor 7 when only the motor 8 in Figure 4 is rotated, and Figure 8 is a diagram showing the basic operation of the tip of the motor 7 in Figure 4. A diagram showing the trajectory of the tip of the motor 7 when rotated, FIG. 9 is an explanatory diagram for operating the tip of the motor 7 on the x-z plane, and FIGS. 10 to 13 are FIG. 9. This is a diagram for explaining the operation in detail, and the operation shown in FIG. Figure 14 shows the relationship between the two operations and the z-axis, the plan view of Figure 11, the triangles P-P ₀ - P ₆ and triangles P-P ₃ - P ₄ in Figure 11, and Figure 14 FIG. 15 is a perspective view of an example of the joint device, FIG. 15 is a plan view showing the state of the mark F attached to FIG. 3 shown in FIG. be. 1...first axis, 2...second axis, 3...third axis,
4, 4', 5... Rotating shaft, 6... Bearing, 7,
8...Motor, 9A...Annular connection means, 9B, 9
C... Fixing means, 10... Spherical operating range, 4C,
4C', 5C... Center line, 40, 50... Moving plate, 70, 80... Motor output shaft, A, B... Rotation direction of the first and second axes, P... Rotating shafts 4, 5 The intersection of the centers of a...rotating shafts 4 and 5 and the moving plate 40,
Angle formed by 50, F... Mark, x, y, z... Coordinate axes, 41, 42, 51, 52... Locus, 51C...
...Center line of the locus 51, g...Inclination of the tip of the motor 7, x...Rotation angle, M1, M2...Rotation angle of the rotation axes 5, 4, R...From the intersection P to the tip of the motor 7 Length, 100, 110, 120, 13
0, 140, 150, 160, 170...each calculation block, 200...circuit block for calculating the common angle x, 300...circuit block for calculating the rotation angles M1, M2.

Claims (1)

[Scope of Claims] 1. First and second shafts that rotate so as to slide on each other on sliding surfaces that are made of planes that form a certain angle with respect to each other around their intersection points; a third shaft that is provided on an extension of the shaft and rotationally drives the first shaft; and a fourth shaft that is provided on an extension of the second shaft and rotationally drives the second shaft.
the first shaft is rotatably held relative to the third shaft, and the second shaft is rotatably held relative to the third shaft.
The shaft is held so as to be rotatable relative to the fourth shaft, and the first diameter of the annular connecting means and the annular connecting means are arranged such that the center of the sliding surface coincides with the center of the sliding surface. The third shaft is connected to the annular connecting means by a first fixing means mounted for rotation about an axis which is perpendicular to the first diameter and which Articulating device, characterized in that said fourth axis is connected to said annular connecting means by a second fixing means mounted so as to be rotatable about an axis having a diameter of 2. 2. First and second shafts that rotate so as to slide on each other on sliding surfaces that are made of planes that form a certain angle a with respect to each other with the intersection point as the center, and a third shaft that is provided and rotationally drives the first shaft; and a fourth shaft that is provided on an extension of the second shaft and rotationally drives the second shaft; The shaft is held rotatably relative to the third shaft, the second shaft is held rotatably relative to the fourth shaft, and the center of the sliding surface and the The third shaft is connected to the annular connecting means by means of a first fixing means mounted so as to be rotatable about an axis having a first diameter of the annular connecting means with respect to the annular connecting means arranged so that the centers coincide with each other. said fourth axis by means of second fixing means mounted so as to be rotatable about an axis which is connected to said first diameter and which is orthogonal to said first diameter and which is a second diameter of said annular connecting means; is connected to the annular connecting means, the angle between the extension line of the second axis and the first axis is an intersection angle g, passing through the intersection of the first axis and the second axis, and When the second axis is the z-axis, the angle formed by the projection of the first axis on the x-y plane perpendicular thereto with the x-axis is the azimuth angle b, and the intersection angle g and the azimuth b are As an input ^, the common angle X for rotationally driving the first and second axes from the intersection angle input is expressed by the formula °-a))); a circuit that obtains a rotational drive output for the first axis by adding the azimuth angle to the obtained common angle; and a circuit for obtaining a rotational drive output for the second shaft.