JPH04315589A - Articulated manipulator having seven degrees of freedom - Google Patents

Abstract

PURPOSE:To simplify control calculation of an action mechanism setting a crossing point as a reference point by crossing at least the action axes of joints of a shoulder part among respective three joints of a shoulder part and a wrist part. CONSTITUTION:An upper arm part 16, a elbow part 18, a front arm part 20, and a wrist part 22 are connected to a shoulder part 14 supported with a base part 12, and hence an articulated manipulator having seven degrees of freedom is constituted. Three shoulder joints R1, R2, P3 are provided in the shoulder part 14, and three wrist joints R5, P6, R7 are provided in the wrist part 22. In this case, the shoulder part is at least formed out of three shoulder link elements containing at least one crank shaped link element. Further, the wrist part is also formed out of three link elements, at least the action axes of the joints of the shoulder part 14 are crossed at one point, and it is favorable that the action axes of the joints of the wrist part 22 are also crossed at one point.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an articulated manipulator, and in particular, to an articulated manipulator that is capable of improving the operability of the operating point of an end effector attached to the tip of the manipulator.
This invention relates to a degree-of-freedom articulated manipulator.

0002

[Prior Art] By positioning the operating point of an end effector installed at the most advanced point in the operating mechanism of an industrial manipulator or robot at an arbitrary position and in an arbitrary direction in a three-dimensional space, a manipulator or robot can be operated. In order to perform processing, assembly, and various other predetermined tasks according to programs, it is accepted as a necessary and sufficient condition that the manipulator or robot has six degrees of freedom of movement, and it is accepted that the degree of freedom of movement of manipulators and robots is six degrees of freedom. Although manipulators and robots with this structure have been put into practical use for specialized purposes, structures having six degrees of freedom have recently become mainstream in many industrial manipulators and robots.

However, in a manipulator or robot with 6 degrees of freedom, the posture of the operating mechanism, that is, the posture of the arm mechanism when positioning the end effector provided at the tip at a certain position and posture in space, is limited to a finite number of postures. In general, multi-jointed industrial robots and manipulators have only about 8 different types. Therefore, in a six-degree-of-freedom manipulator or robot, when positioning the end effector at a certain position and in a certain posture, the posture of the arm mechanism must be selected from among this finite number of possible postures. Therefore, when the arm mechanism assumes a limited posture, in an environment where there is interference with surrounding obstacles, the end effector may not be able to be positioned at the desired position and in the desired posture. On the other hand, if interference with the surroundings is completely eliminated in advance, the work area of the manipulator or robot will become large-scale, making it difficult to introduce the robot or manipulator by effectively utilizing the work area.

Considering that manipulators and robots with 6 degrees of freedom of motion still have the above-mentioned drawbacks, we compared the arm mechanisms of these manipulators and robots with the human arm, and found that the latter is superior to industrial manipulators and robots. The manipulator has the ability and dexterity to perform complex movements after discovering that the arm, which is connected to the human torso through the shoulder and including the wrist, has seven degrees of freedom. Devices have already been proposed (for example, Japanese Patent Publication No. 55-4895).
Publication No. 6). In other words, the arm mechanism of a manipulator or robot having seven degrees of freedom allows the end effector installed at the most advanced point to have a function to avoid obstacles, and also increases the degree of freedom of movement of the manipulator or robot itself. The seventh degree of freedom can be used to avoid the occurrence of postural conditions that reduce posture, compensate for the limited range of motion of rotary joints, and expand the range of motion that the end effector can reach. Therefore, it has a configuration that allows more complex and advanced robot work to be performed.

[0005]

[Problem to be solved by the invention] However, the conventional 7
The manipulator with a degree of freedom was developed by the above-mentioned Special Publication Publication No.
Many manipulators, including the manipulator disclosed in Japanese Patent No. 8956, have two degrees of freedom of movement in the shoulder supported by a support, one degree of freedom in the upper arm, and one degree of freedom in the elbow, as shown in FIG. It has a configuration in which the forearm has one degree of freedom of movement and the wrist has two degrees of freedom of movement, and each degree of freedom of movement is formed by a joint, and the joint is formed by a rotational joint or a swivel joint. ing. Now, considering rotary joints and swivel joints,

In the former case, in a manipulator or robot, when the arm mechanism is in a horizontal posture as the basic posture, the second link element is connected to the tip of the joint provided at the tip of the first link element. by rotating the second link element about its central or longitudinal axis, the effect of the rotation is to create a "torsion" in the second link element.
Alternatively, a joint for performing a rotational movement similar to a "twisting" action can be defined as a rotational joint, and generally, it is a symbol between the first link element, the joint R, and the second link element.

[Example 1] is displayed. On the other hand, the latter pivot joint is a second link connected to the tip of the joint provided at the tip of the first link element when the manipulator or robot arm is considered to have a horizontal posture as the basic posture. When the element turns at the joint in a circular arc with the central axis or longitudinal axis of the second link element as a radius, the tip of the second link element moves to various positions on the arc locus as an effect of the turning. can be defined as a pivot joint, which is generally a symbol between the first link element, the joint P, and the second link element.

[Outside 2] It will be displayed like this.

However, the configuration of the 7-degree-of-freedom manipulator shown in FIG. This mechanism has been created to imitate human arm function as much as possible with the aim of reducing discomfort. Therefore, the teaching-playback method, which is more widely adopted in industrial applications,
Although improvements have been made in that it is not a degree-of-freedom manipulator and that the 7-degree-of-freedom manipulator using the teaching-playback method has complicated motion control as the number of degrees of freedom increases, However, since the movement mechanism from the shoulder to the upper arm is complicated and the upper arm has a rotary joint, the weight of the arm as a whole is inevitably large.

On the other hand, in a teaching-playback type 7-degree-of-freedom manipulator or robot, each joint of the arm mechanism is operated independently during the teaching process to make the end effector attached at the most advanced position reach the target position and posture. It is essential to be able to perform axis-independently operated teaching. In other words, in order to accurately perform the desired manipulator work by finely controlling the position and posture of the end effector, for example, it is possible to achieve the same position and posture of the end effector even if the elbow position of the arm mechanism is changed. if you can,
This is an essential requirement because it makes it possible to position the tip of the end effector in the same position and posture without causing interference between the arm mechanism and surrounding equipment in three-dimensional space, and therefore the above-mentioned axis independence is required. A configuration that allows for operational teaching is essential.

Accordingly, an object of the present invention is to provide a teaching-playback type manipulator or robot that is widely applicable to industrial applications. Another object of the present invention is to have a structure that is dexterous and complex like a human arm, has a relatively simple structure, and can avoid an increase in the weight of the arm (upper arm + forearm). It is an object of the present invention to provide a manipulator with articulated degrees of freedom. Still another object of the present invention is to have a structure that can avoid complication of the control method and teach a desired working position and posture to the end effector by independently operating each rotational and pivoting joint of the arm mechanism. It is an object of the present invention to provide a manipulator with articulated degrees of freedom.

0010

[Means for Solving the Problems] In view of the above-mentioned object of the invention, the present invention includes a shoulder supported by a base, an upper arm, an elbow, a forearm, and a wrist connected to the shoulder. In the 7-degree-of-freedom articulated manipulator, the shoulder part includes three shoulder link elements between the base part and the upper arm part, and three shoulder joints connected to the tips of each shoulder link element, and The wrist portion includes three wrist link elements connected to the distal ends of the forearm link elements, and an elbow joint that connects the upper arm link element forming the upper arm and the forearm link element forming the forearm, and the wrist portion includes three wrist link elements connected to the distal ends of the forearm link elements. 3 connected to the rear end of the wrist link element
and at least one link element of the three shoulder link elements of the shoulder portion is formed into a crank-shaped link element, so that the three shoulder joints have their joint axes aligned with the upper arm. It is an object of the present invention to provide a 7-degree-of-freedom articulated manipulator that is arranged to intersect at one point on the axis of the shoulder joint connected to the shoulder joint.

The present invention also provides a seven-degree-of-freedom articulated manipulator comprising a shoulder supported by a base, an upper arm, an elbow, a forearm, and a wrist connected to the shoulder, wherein the shoulder is connected to the shoulder. The forearm is provided with three shoulder link elements between the base and the upper arm, and three shoulder joints connected to the tips of the shoulder link elements, the upper arm link element forming the upper arm at the elbow and the forearm. and a forearm link element forming a forearm link element; a joint, and at least one link element of the three shoulder link elements of the shoulder portion is formed into a crank-shaped link element, such that the three shoulder joints connect their joint axes to the base. The present invention provides a seven-degree-of-freedom articulated manipulator that is disposed at the tip of a shoulder link element that intersects at one point on the axis of the shoulder joint.

[0012] In each of the above two 7-degree-of-freedom articulated manipulator configurations, it is preferable that the three wrist joints also have a configuration in which the axes of the three wrist joints intersect at one point on the axis of one of the joints. . Hereinafter, the present invention will be described in detail according to embodiments shown in the accompanying drawings.

[0013]

[Example] Fig. 1 is a two-dimensional mechanical diagram showing the basic structure and arrangement of the link elements and joints from the shoulder to the wrist that constitute the 7-degree-of-freedom articulated manipulator according to the present invention, and Fig. 2 is a diagram. FIG. 3 is a three-dimensional mechanical perspective view showing the configuration of the manipulator shown in FIG. 1, and FIG. FIG. 4, a perspective view showing a specific configuration, shows that the manipulator shown in FIG. FIGS. 5(a) to 5(e) are perspective views illustrating that independently operated teaching can be performed; FIGS. FIGS. 6(a) to 6(f) are similar mechanical diagrams to FIG. 1 showing other embodiments and modifications of the present invention.

First, referring to FIGS. 1 and 2, the 7-degree-of-freedom articulated manipulator according to the present invention is formed as an arm mechanism 10 supported by a fixed base 12, and the arm mechanism 10 includes a shoulder 14, an upper arm part 16, elbow part 18, forearm 2
0, a wrist portion 22, and an arm mechanism 10 made up of these parts includes seven joints consisting of a rotating joint R or a pivoting joint P. The shoulder portion 14 is the fixed base 1
2, a first shoulder link element 14a supported directly on the first
Shoulder joint R1, second shoulder link element 14b, second shoulder joint R2, third shoulder link element 14c, third shoulder joint P3
It is equipped with At this time, the second shoulder link element 14b serves as a crank-shaped link element that connects the first and second shoulder joints R1.
, R2, and as a result, the respective operating axes a1, a2, and a3 of the three shoulder joints R1, R2, and P3 of the shoulder portion 14 have a mutually orthogonal relationship and a They intersect at one point Os on the motion axis a3 of the shoulder joint P3 of No. 3. In other words, the three operating axes are at the one point Os
Since orthogonal coordinate axes are formed with the origin as the origin, control calculations for rotation or turning operations about these three operation axes a1 to a3 are simplified. Further, the upper arm portion 16 and the forearm portion 20, which are pivotally connected to the third shoulder joint P3 and can pivot around the motion axis a3, can pivot relative to each other via a joint P4 provided on the elbow portion 18. combined. That is, when a relative rotational movement is performed between the upper arm 16 and the forearm 20 around the motion axis a4 of the elbow joint P4 of the elbow 18, the upper arm 1
6. The angle between the forearm parts 20 is controlled to be wide or narrow.

Furthermore, the wrist portion 22 has a first wrist joint R5, a first wrist joint R5, and a
The third wrist link element 22c includes a wrist link element 22a, a second wrist joint P6, a second wrist link element 22b, a third wrist joint R7, and a third wrist link element 22c. It forms the attachment end of an end effector (not shown). Furthermore, in this wrist portion 22 as well, the motion axes a5 to a7 of the first to third wrist joints R5, P6, and R7 intersect at a point Ow on the motion axis a6 of the second wrist joint P6 in this example. It has a structure. In this way, due to the configuration in which the motion axes a5 to a7 of the three joints R5, P6, and R7 intersect at one point, this one point Ow
Since the rotation and turning motions around the three axes can be defined using the reference point, calculations for controlling the motion of the wrist portion 22 are not complicated. Note that the motion axis a5 and the motion axis a4 of the joint P4 of the elbow portion 18 are configured to intersect on the same motion axis a4.

According to the above-described configuration, the arm mechanism 10 has a degree of freedom in turning or rotating at the seven joints R1 to R7, and moreover, each of the three joints at the shoulder section 14 and the wrist section 22 has a degree of freedom. Since it has a configuration in which the arms intersect at one point Os and Ow, the function of the arm mechanism 10 can exhibit a movement function similar to that of a human arm from the shoulder to the wrist.
Therefore, redundancy in degrees of freedom (redundancy) is increased compared to conventional manipulators and robot arm mechanisms with 5 to 6 degrees of freedom, and the end effector attached to the tip of the wrist portion 22 can be positioned in three-dimensional space. When controlling the posture, it is possible to perform the function of avoiding an obstacle by detouring around it or positioning the robot at a position behind the obstacle. Now, the specific configuration in the case where the shoulder portion 14 of the 7-degree-of-freedom articulated manipulator according to the embodiment of the present invention described above has a drive source for rotating or pivoting at the shoulder joints R1, R2, and P3 is shown in FIG. 3.

According to FIG. 3, the drive source for the first shoulder joint R1 is formed by a drive motor M1 equipped with a speed reduction mechanism whose rotation center is the motion axis a1, and this drive motor M1 itself drives the first shoulder joint R1. The stationary outer housing of the motor M1 forms an element equivalent to the first shoulder link element 14a, and the output shaft (not shown) of the drive motor M1 and an L-shaped structure coupled to the output shaft. A crank-shaped link element 34 having a section forms a second shoulder link element 14b. A drive motor M2 with a reduction gear that forms the second shoulder joint R2 and drives rotation about the axis a2 is provided at the end of the crank-shaped link element 34, and drives the second shoulder joint R2. forming the source. Furthermore, the output shaft 36 of the second drive motor M2 forms a third link element 14c in the shoulder 14, and the output shaft 36 of the second drive motor M2 forms the third link element 14c.
6 is coupled via a bracket 38 to an outer housing of a drive motor M3 with a speed reducer that forms a drive source for turning around the axis a3 at the third shoulder joint P3. A rod-shaped member 42 forming the upper arm 16 is coupled to a cylindrical element 40 directly connected to the output shaft of the drive motor M3 forming the third shoulder joint P3.

In the specific embodiment of the shoulder portion 14 shown in FIG. By providing the bracket 38, a configuration is realized in which the orthogonal points of the motion axes intersect at one point Os on the motion axis of the third shoulder joint P3 (Os: the intersection of the motion axes of the three shoulder joints). -ing Next, FIG. 4 shows that in the arm mechanism 10 of the 7-degree-of-freedom articulated manipulator according to the embodiment of the present invention shown in FIG. P6
, R7, and one joint P4 in the elbow part 18, the movement axes a5 to a7 of the wrist part 22
While maintaining the intersection Ow (Ow: the intersection of the motion axes of the three joints of the wrist part 22) at a constant point, the joint P of the elbow part 18
It is explained that it is possible to displace 4 to different positions. That is, in FIG. 4, first, the elbow portion 18
One point Oe at joint P4 (upper arm 16 and forearm 20
and the intersection point of the central axis a4 of the joint P4 of the elbow part 18 and the central axis a5 of the first joint R5 of the wrist part 22) is at the position shown by the dotted line, and at this time, the wrist part 22 It is assumed that the intersection point Ow is at the position shown. Next, assume that a rotational motion is driven at the second shoulder joint R2 in the shoulder portion 14. As a result, since the mechanism on the distal side from the second shoulder joint R2 in the arm mechanism 10 is rotated around the motion axis a2, the motion axis a3 of the third shoulder joint P3 moves to a3', and the point at the elbow portion 18 is rotated about the motion axis a2. Joint P4 with Oe is displaced to the position shown by the solid line. In other words, point Oe
moves to point Oe'. From this result, the point Ow on the wrist 22 also moves to the point Ow', but then the first point on the shoulder 14 moves to the point Ow'.
, by driving the rotation and turning of the third shoulder joints R1 and P3, it becomes possible to return the point Ow' of the wrist portion 22 to the position of the point Ow again. In other words, the point Ow on the wrist portion 22
It can be seen that the point Oe of the elbow portion 18 can take two different positions while keeping the point Oe immobile.

That is, referring to FIG. 7, the figure shows the elbow portion 18 when the point Ow of the wrist portion 22 is fixed at a fixed position.
This figure shows the trajectory of the motion of the elbow 18.
It is shown that e can take any position on the locus circle Ce, if the actual movable angle range of each joint is not considered. If the distance between the point Os on the shoulder 14 and the point Oe on the elbow 18 is L1, and the distance between the point Oe on the elbow 18 and the point Ow on the wrist 22 is L2, then the lengths of L1 and L2 are Since the height is always constant, the distance of point Oe from point Os is L1 and the distance from point Ow is L2. Therefore, the position of point Oe on the elbow 18 is within the radius around the shoulder point Os. It is limited to a circumference Ce that is a ray of light from a sphere L1 and a sphere having a radius L2 centered at a point Ow on the wrist portion 22. Furthermore, as described above, the manipulator according to this embodiment has three independent joints in the shoulder 14, so that the point Oe of the elbow can be positioned at any point on the circumference Ce, and the elbow It is possible to orient the direction of the motion axis a4 of the joint P4 in the tangential direction of this circumference Ce at the point Oe. This makes it possible to move the point Oe of the elbow 18 to any position on the circumference Ce perpendicular to the straight line connecting the points Os and Ow while keeping the point Ow of the wrist 22 at a constant position. In other words, in conventional manipulators or industrial robots with six degrees of freedom, the shoulder has only two joints, so when the elbow is positioned, the direction of the axis of motion of the elbow joint is uniquely determined. This has the disadvantage that the elbow point cannot be moved while the position of the center point of the wrist is fixed.

Here, further, with reference to FIGS. 4 and 8, the operation of keeping the point Ow of the wrist portion 22 at a fixed position and teaching a different posture to the point Oe of the elbow portion 18 will be briefly explained below. First, when moving the elbow portion 18 while fixing the hand portion at a fixed position, even if the position of the elbow portion 18 changes, the point O of the shoulder portion 14
The distance between s and the point Ow of the wrist 22, that is, the distance (Os-
Since Ow) remains unchanged, the joint angle of the joint P4 of the elbow portion 18 does not change during this movement. Furthermore, since the three joints R5, P6, and R7 of the wrist portion 22 do not contribute to the change in the position of the point Ow, the movement of moving the elbow portion 18 while fixing the same point Ow at a fixed position is, after all, the movement of the shoulder portion 14. 3 joints R
This can be realized by changing the joint angles of 1, R2, and P3. 3 of the shoulder part 14 without moving the joint P4 of the elbow part 18.
When only the three joints R1, R2, and P3 are moved, the wrist 22
The point Ow is centered on the point Os on the shoulder 14 and has a radius of Os.
-Moves on the sphere of Ow. This spherical surface is now denoted as S as shown in FIG. After positioning the point Ow of the wrist part 22 at a certain position in space, the position of the point Ow is the same and the position of the elbow part 1 is determined by independent control.
To teach the manipulator or robot a different posture than position 8, move shoulder 1 from this initially positioned posture.
It is sufficient to appropriately move only the three joints R1, R2, and P3 of No. 4 to realize a posture in which the point Ow of the wrist portion 22 is the same as the original position.

Here, each motion axis is moved in the order of R2 → P3 → R1 at the joint of the shoulder 14 based on the initial positioning posture, and the point Ow of the wrist 22 is the same, and the point Oe of the elbow 18 is moved. The procedure for teaching the robot postures with different positions will be explained. Note that the order of moving the three joints R1, R2, and P3 of the shoulder 14 in order to change the elbow position without moving the hand position is not limited to the above order R2 → P3 → R1, but can be It is also possible in any order. However, since the above order seems to be easier to intuitively understand the movements of the robot's tip and arm, the above order is R2→P3→R.
The case where the teaching operation is performed in 1 will be explained.

First, it is assumed that in the initial state, the elbow portion 18 and wrist portion 22 are at the points Ow and Oe indicated by broken lines in FIG. To move the three joints of the shoulder 14 in the order of R2→P3→R1 and teach different postures regarding the point Oe of the elbow 18, first move the second joint R2 of the shoulder 14 appropriately. After tilting the arm made up of the upper arm 16 and the forearm 20 and changing the elbow position, move the first joint R of the remaining shoulder 14.
Move the 1st and 3rd joints P3 appropriately and return the hand position to the original point O.
It is sufficient to match w. Here, the second joint R of the shoulder portion 14
2, the parts beyond the shoulder 14 (upper arm 16, forearm 20, wrist 22) rotate around the motion axis a2, and the point of the wrist moves from Ow to Ow'. At this time, the point Ow of the wrist portion 22 is the arc C2 on the spherical surface S mentioned above.
move above. Further, the motion axis a of the third joint P3 of the shoulder portion 14
3 changes to the direction of axis a3'.

Next, when the second joint R2 of the shoulder part 14 is moved, the parts beyond the shoulder part 14 (upper arm 16, forearm 20, wrist part 22) rotate around the motion axis a2, and the wrist part 2
Move from point 2 Ow to Ow'. At this time, the wrist point moves on the arc C2 on the spherical surface S described above. Also, shoulder part 1
The direction of the motion axis a3 of the third joint P3 of No. 4 changes to a3'. Next, when the third joint P3 of the shoulder section 14 is moved from this state, the point of the wrist section 22 is displaced along the arc C3 on the spherical surface S. Here, the circular arc C3 is perpendicular to a spherical surface S with a radius Os-Ow centered on the point Os and a point Os
is the line of intersection with the plane passing through. Move the third joint P3 of the shoulder part 14 by an appropriate angle to change the point of the wrist part 22 to the point Ow in FIG.
However, the point Ow is a point on the arc C3 whose height measured from the fixed base 12 along the direction of the motion axis a1 is the same as the original point Ow. .

Finally, move only the first joint R1 of the shoulder 14, and move the point of the wrist 22 to the original point Ow along the arc C1 on the plane perpendicular to the motion axis a1. Move the joint R1 until they match. Note that FIG. 8 is a diagram showing the movement of the intersection of the wrist joints when the three joints R1, R2, and P3 of the shoulder portion 14 are moved in the above order. As can be understood through the explanation of the above embodiments, from the structure of the articulated manipulator having 7 degrees of freedom according to the present invention,
When the end effector attached to the wrist 22 is positioned at a predetermined position and posture by driving the three shoulder joints R1, R2, and P3 of the shoulder 14, the elbow 18 can take two different positions. Therefore, even when some kind of obstacle exists at one elbow position, it is possible to reach the desired position and posture of the wrist tip position via another elbow position, and the operability of the arm mechanism 10 is improved. can be achieved.

FIG. 5 shows a modified embodiment of the mechanism of the embodiment shown in FIG. 1 of the 7-degree-of-freedom articulated manipulator according to the present invention. That is, in the modified embodiments shown in FIGS. 5(a) to 5(e), the configuration of the shoulder portion 14 with respect to the fixed base 12 is completely the same as that in FIG. 1. However, in the embodiment shown in (a), the first wrist joint of the wrist portion 22 is formed as a rotation joint P5, and the second and third wrist joints are formed as rotation joints R6 and R7. In this embodiment, the second wrist link element 22b of the wrist portion 14 is formed as a crank-shaped link element. In this case, the motion axes a5 to a7 of the wrist portion 22 intersect at one point on the motion axis a5 of the first wrist joint P5.

The modification shown in FIG. 5(b) also has the following:
The configuration of the wrist portion 22 is different, with the first and second wrist joints being formed as rotary joints R5 and R6, and the third wrist joint being formed as a swivel joint P7. The first wrist link element 22a then forms a crank-shaped link element. In FIG. 5(c), the elbow part 18 is formed by a rotary joint R4, and the joint configuration of the wrist part 14 is such that the first and third wrist joints are formed by rotary joints R5 and R7, and the second wrist joint is formed by a rotary joint R5 and R7. It is formed by a pivot joint P6. In this example, the upper arm 16 and the forearm 20 form a crank-shaped link element. Of course, the motion axes a5 to a7 of the joints of the wrist portion 22 are configured to intersect at one point (on the motion axis of the second joint P6). In the modified examples of FIGS. 5(d) and 5(e), the joint of the elbow portion 18 is the same as that of the embodiment shown in FIG. , the latter is an example of a configuration similar to that of (b). It goes without saying that each of these modified embodiments has the same functions and effects as the 7-degree-of-freedom articulated manipulator according to the embodiment shown in FIG.

FIG. 6 shows another embodiment of the arm mechanism 10 of the 7-degree-of-freedom articulated manipulator according to the present invention. That is, in the embodiment shown in FIG. 6, in the shoulder portion 14, the third shoulder link element 14c is formed as a crank-shaped link element, and the first shoulder joint is the swivel joint P1 when viewed from the fixed base 12 side. The second and third shoulder joints are formed by rotary joints R2 and R3, and the motion axes a1 to a3 of these three shoulder joints are aligned with the first shoulder joint P.
This is an embodiment in which the two operating axes intersect at one point. The structure of the upper arm, elbow, forearm, wrist, etc. on the distal side from the third shoulder joint R3 is the same as that of the manipulator in FIG. 1. . Furthermore, the structure from the upper arm part in each of the modified embodiments shown in FIGS. 6(b) to 6(f) is the same as that shown in FIGS.
Each corresponds to each configuration shown in . The manipulator according to the embodiment of FIG. 6 also has seven degrees of freedom of movement in that the shoulder portion 14 has three joints, the elbow portion 18 has one joint, and the wrist portion 22 has three joints. It goes without saying that basically the same functions and effects as those of the embodiments shown in FIGS. 1 and 5 can be achieved.

[0028]

As is clear from the above description, according to the present invention, a 7-degree-of-freedom articulated manipulator has a shoulder portion that is directly connected and supported by a fixed base, an upper arm and an elbow that are sequentially connected to this shoulder portion. It is formed as an arm mechanism having a forearm, a forearm, and a wrist, and has three joints at the shoulder, one joint at the elbow, and three joints at the wrist. The axes of motion of at least the former shoulder of each of the three joints of the wrist are configured to intersect at one point, and preferably the axes of motion of both the shoulder and wrist are configured to intersect at one point. It is possible to simplify the control calculations for the operating mechanism using the reference point as the reference point, and because of the configuration with 7 degrees of freedom, it is possible to move the end effector attached to the wrist to a predetermined position and posture while avoiding obstacles on the way. It is possible to teach the movement of positioning to the object, and it is also possible to realize the movement of positioning on the back side of the obstacle. As a result, even when the manipulator is used in a teaching-and-playback manner at a work site, it is possible to avoid obstacles in the surrounding environment and perform the desired manipulator work or robot work as dexterously as if using a human arm. It can be accomplished. In other words, the reachable range of the manipulator can be expanded compared to conventional 6-degree-of-freedom manipulators, robots, and the like.

Furthermore, since the 7-degree-of-freedom manipulator of the present invention has three joints in the shoulder, only one joint is required in the upper arm, elbow, and forearm, which simplifies the mechanism and reduces the arm mechanism. Since it is possible to achieve a weight reduction of
It is also possible to improve the controllability of the arm mechanism.

Furthermore, since it is possible to change the position of the elbow to two or more positions while maintaining one point of the wrist at a fixed position, if an obstacle is found on the way during the teaching process, the position of the elbow can be changed. An end effector worn on the wrist by displacing only one part has the advantage of being able to perform the same manipulator work. This means that the position of the end effector at the tip of the wrist can be determined using the four joints provided at the shoulder and elbow, and the posture of the end effector can be determined using the three joints provided at the wrist.
It is also possible to change only the posture at the same position using two joints. Therefore, the position control and posture control of the end effector can be performed separately, and each joint can be controlled independently to change the end effector. Since the end effector can be controlled to a desired position and posture, the operator can easily grasp the operation of the end effector and achieve appropriate control.

[Brief explanation of the drawing]

FIG. 1 is a two-dimensional mechanical diagram showing the basic configuration and arrangement of link elements and joints from a shoulder to a wrist that constitute a 7-degree-of-freedom articulated manipulator according to the present invention.

FIG. 2 is a three-dimensional mechanical perspective view showing the configuration of the manipulator shown in FIG. 1;

FIG. 3 is a perspective view showing a specific configuration of the shoulder portion of the 7-degree-of-freedom manipulator according to the present invention shown in FIGS. 1 and 2, having drive means at each joint.

[Fig. 4] In the manipulator shown in Fig. 1, by operating the manipulator in the axis-independent operation method, the position of the elbow can be changed while keeping one point of the wrist immobile, so the axis-independent operation type teaching is performed. FIG.

5(a) is a mechanical diagram similar to FIG. 1, showing a modification of the mechanism of the 7-degree-of-freedom manipulator shown in FIG. 1; FIG. (b) is a mechanical diagram similar to FIG. 1 showing another modified example of the mechanism of the 7-degree-of-freedom manipulator shown in FIG. 1. (c) is a mechanical diagram similar to FIG. 1 showing yet another modified example of the mechanism of the 7-degree-of-freedom manipulator shown in FIG. 1. (d) is a mechanical diagram similar to FIG. 1 showing another modified example of the mechanism of the 7-degree-of-freedom manipulator shown in FIG. 1. (e) is a mechanical diagram similar to FIG. 1 showing yet another modified example of the mechanism of the 7-degree-of-freedom manipulator shown in FIG. 1.

FIG. 6(a) is a mechanical diagram similar to FIG. 1 showing another embodiment of the present invention. (b) is a mechanical diagram of a modification of (a). (c) is a mechanical diagram of another modification of (a). (d) is a mechanical diagram of still another modification of (a). (e) is a mechanical diagram of yet another modification of (a). (f) is a mechanical diagram of still another modification of (a).

FIG. 7 is a perspective view to help explain that the axis-independently operated teaching according to FIG. 4 can be carried out, showing the locus of movement of the elbow when the intersection of the wrist joints is fixed in a fixed position; It is a diagram.

FIG. 8 is also a perspective view to help explain that the axis-independent operating type teaching according to FIG. 4 can be carried out, and teaches different postures of the position of the elbow without moving the intersection point of the wrist joint; FIG. 3 is an explanatory diagram showing the trajectory of the hand in case

FIG. 9 is a mechanical diagram showing the configuration of a conventional 7-degree-of-freedom articulated manipulator.

[Explanation of sign]

12...Fixed base, 14...Shoulder part, 16...upper arm, 18...Elbow part, 20...Forearm, 22...Wrist part, R1...first shoulder joint, R2...second shoulder joint, P3...Third shoulder joint, P4...Elbow joint, R5...first wrist joint, P6...2nd wrist joint, R7...Third wrist joint.

Claims (6)

[Claims] 1. A seven-degree-of-freedom articulated manipulator comprising a shoulder supported on a base, an upper arm, an elbow, a forearm, and a wrist connected to the shoulder, wherein the shoulder is connected to the base and the upper arm. and a forearm, comprising three shoulder link elements and three shoulder joints connected to the tips of the respective shoulder link elements, and a humeral link element forming the upper arm and a forearm forming the forearm at the elbow part. and an elbow joint that connects the forearm link elements, and the wrist portion includes three wrist link elements that are connected to the distal ends of the forearm link elements, and three wrist joints that are connected to the rear ends of each wrist link element. and at least one link element of the three shoulder link elements of the shoulder portion is formed into a crank-shaped link element, whereby the three shoulder joints connect their joint axes to the upper arm of the shoulder joint. A 7-degree-of-freedom articulated manipulator characterized in that the manipulators are arranged so as to intersect at one point on the axis. 2. Of the three shoulder link elements in the shoulder portion, the second and third shoulder link elements viewed from the base side are formed as the crank-shaped link elements, and the three shoulder joints are formed as crank-shaped link elements. 7 according to claim 1, wherein the rotary joint, rotary joint, and pivot joint are arranged in this order from the base side.
Articulated manipulator with degrees of freedom. 3. The three wrist joints of the wrist portion are arranged such that their joint axes intersect at one point on the axis of any one of the three wrist joints. The 7-degree-of-freedom articulated manipulator according to claim 1. 4. A seven-degree-of-freedom articulated manipulator comprising a shoulder supported on a base, an upper arm, an elbow, a forearm, and a wrist connected to the shoulder, wherein the shoulder is connected to the base and the upper arm. and a forearm, comprising three shoulder link elements and three shoulder joints connected to the tips of the respective shoulder link elements, and a humeral link element forming the upper arm and a forearm forming the forearm at the elbow part. and an elbow joint that connects the forearm link elements, and the wrist portion includes three wrist link elements that are connected to the distal ends of the forearm link elements, and three wrist joints that are connected to the rear ends of each wrist link element. and at least one link element of the three shoulder link elements of the shoulder portion is formed into a crank-shaped link element, such that the three shoulder joints connect their joint axes to the base. A 7-degree-of-freedom articulated manipulator, characterized in that the manipulator is arranged so as to intersect at one point on the axis of the shoulder joint provided at the tip of the shoulder joint. 5. The second and third shoulder link elements of the three shoulder link elements in the shoulder portion viewed from the base side are formed as the crank-shaped link elements,
The three shoulder joints are, from the base side, a swivel joint, a rotation joint,
4. The 7-degree-of-freedom articulated manipulator according to claim 3, wherein the manipulator is arranged in the order of revolute joints. 6. The three wrist joints of the wrist portion are arranged such that their joint axes intersect at one point on the axis of any one of the three wrist joints. The 7-degree-of-freedom articulated manipulator according to claim 3.