JP4195945B2 - Robot path creation method and apparatus - Google Patents

Description

  The present invention relates to a route creation method and apparatus for a robot that performs a predetermined work in a two-dimensional or three-dimensional work space.

Robots such as manipulators are indispensable for the automation of manufacturing sites, etc., but when setting the movement path of a manipulator, it is necessary to make sure that each arm constituting the manipulator does not interfere with obstacles during the movement process. Don't be.
Conventionally, the operator manually set the movement route before starting the work with the manipulator, but in the environment of high-mix and low-volume production, the arrangement of obstacles changes frequently and automatically There is an increasing demand for technology for determining travel routes.
For this reason, various proposals have been made for techniques for automatically obtaining the movement path of a manipulator (see, for example, Patent Documents 1 to 3).
JP 10-76489 A (see paragraphs [0012] to [0014] of the specification) JP-A-6-348330 JP 2000-20117 A

The technique disclosed in Patent Document 1 is a robot arm teaching method and apparatus in which an operator teaches a robot arm a path along which the robot arm moves. Therefore, in this technique, even if the movement path of the manipulator is automatically obtained, manual operation by an operator is indispensable as a precondition.
The technique disclosed in Patent Document 2 relates to a playback-type work robot. In the same manner as in Patent Document 1, the operator previously teaches the robot arm the path along which the robot arm moves.

  Here, the “playback type” is a type in which an operator operates a robot in advance before work to teach the work, and data is reproduced and executed at the time of work. However, there are disadvantages that work cannot be reproduced unless the environment in which the data is created is the same as that in which the data was created, or work data using sensor information cannot be created. Therefore, in the technique described in this document, manual operation by an operator is indispensable as a precondition.

If an attempt is made to automatically determine the movement path of the manipulator, for example, as described in paragraph [0004] of the specification of Patent Document 3, a large amount of lattice point information has to be processed and the movement is performed at high speed. There is a problem that it is difficult to automatically determine the route. The technique described in Patent Document 3 attempts to solve such a problem, but a backtrack occurs in the route creation process, and it is necessary to recalculate each time. Therefore, there is a limit to shortening the route creation time. There is a problem that there is.

  The present invention has been made in order to solve the above-described problems. In creating a route for a robot that performs a predetermined work in a two-dimensional or three-dimensional work space, particularly for creating a route for a manipulator having two or more arms. An object of the present invention is to provide a robot route creation method and apparatus capable of creating a route in a short time without a backtrack in the route creation process with a small amount of data and a small calculation load. .

In order to achieve the above object, the inventor of the present invention, in a robot such as an articulated arm robot, determines where the arm can move with respect to an arbitrary n-th arm among N arms. We focused on whether or not it can move without interfering with obstacles.
Therefore, the inventor of the present invention has come up with the idea that the object of the present invention can be achieved by using three concepts of “holdable posture, n connectable relationship, and n−1 connectable relationship”.
Also, if the set of postures that can be held by each arm of the robot is not divided into multiple connected components by obstacles at each lattice point in the work space where the robot performs work, the movement paths of the individual arms are sequentially separated. Even if it is calculated that the backtrack does not occur and the arm's holdable posture set is divided into a plurality of connected components by an obstacle or the like, another grid point (for each divided area ( By providing a copy grid point), path calculation without backtracking was realized.

Specifically, the invention according to claim 1 is a set of lattice points including a plurality of spaced points and a region obtained by dividing the work region according to the number of points in a work space in which the robot moves. expressed as, a movement path of the multi-joint robot having n arms (n ≧ 1), a route creation method of the robot to create in the working space of the virtual, among the n arm, the n For the (N ≧ n ≧ 1) arm, the posture is indicated by the position of the reference point at one end that is a fulcrum of movement of the n-th arm and the position of the sub-reference point at the other end. Defines a posture that does not interfere with an obstacle present in the work space as a holdable posture, and for the nth arm belonging to the first to (N-1) th, the obstacle present in the work space N + which is not interfering and is located beyond The posture when the arm has at least one holdable posture is defined as the holdable posture of the nth arm, and the set of holdable postures for each arm with a predetermined lattice point as a reference point is sequentially set from the Nth arm. A step of obtaining each of the N arms up to the first arm to obtain a holdable posture set table, and a lattice point adjacent to the nth arm without interfering with an obstacle based on the holdable posture set table When the sub-reference point is movable between the two lattice points, the pair of the two lattice points is defined as an n-connectable relationship, and the sub-reference point is located at the same lattice point or the sub-reference point is located. When the lattice point pair is in the n-connectable relationship, when the n-th arm can move between adjacent lattice points without interfering with an obstacle, the lattice point pair of the reference point is connected to n-1 Defined as related Then, a step of creating a connectable relationship table which is a set of connectable relationships for each of the N arms from the Nth arm to the first arm in sequence, the holdable posture set table and the connectable relationship table are And determining a path through which the reference points and sub-reference points of the first arm to the N-th arm in a predetermined initial posture move to a target point of each arm through a grid point in a connectable relationship. Is the method.
Whether the sub-reference point of each arm can be positioned at the target point for each arm is determined according to claim 2, in the method for creating a path of the robot according to claim 1, N reachable sets that are sets of points that can be reached via the lattice points that are n connectable to each other from a predetermined initial position for each of the first to Nth arms. It is determined whether or not the target point of the arm is included in the set of n reachable points for each determined arm, and when it is determined that the target point is included, the robot can reach the target point. Judgment is made to create a movement path from the initial posture to the target posture for each of the first arm to the Nth arm.

According to this method, the posture of any n-th arm (n-th arm) among the N arms can be expressed by the position of the reference point at one end and the position of the sub-reference point at the other end. . To maintain the posture of the nth arm,
It is a condition that the N-th arm does not interfere with an obstacle. However , in the n- th arm belonging to the 1st to (N-1) -th, it is not sufficient that the n-th arm does not interfere with the obstacle. It is necessary to have at least one posture in which the connected (n + 1) th arm can hold. Therefore, from the N arms of n = N to the first arm n = 1, the creating a table (retainable posture set table) of holdable posture set to satisfy the above requirements. This table can be said to be a set of postures that a robot having N arms can take in the work space.

Here, “n connectable relationship” and “n−1 connectable relationship” indicate whether or not the reference point or sub-reference point of the n-th arm can move between adjacent lattice points. For example, when the reference point is moved to a lattice point in the n-1 connectable relationship, the sub reference point of the nth arm can be moved by following the lattice point in the n connectable relationship. That is, it can be said that the n connectable relationship and the n-1 connectable relationship indicate a relationship in which the nth arm can move continuously.

In the n-1 connectability relationship described above, if there is at least one pair of holdable postures adjacent to the n-th arm, each of the adjacent lattice points (for example, lattice points P and Q) has a reference point. When n-1 connectable and the two holdable posture set tables of the nth arm in P and Q include the same or n connectable lattice points as the sub reference point position of the nth arm Can be configured by determining that P and Q are n-1 connectable.
The target points of the robot are set as a set of target points to be reached by the sub-reference points of the first to Nth arms, and the paths are n connectable in the n connectable relationship table in the order of the first to Nth. This is created by sequentially moving the grid points from the initial position toward the target point.

Depending on the position of the reference point, the holdable posture set of an arbitrary n-th arm may be divided into a plurality of connected components of lattice points that are n connectable to each other due to an obstacle arranged in the work space. When the holdable posture set is divided into one region and another region, even if the points P, Q and Q, R adjacent to each other are all n-1 connectable, the n-th arm sets its reference point to P , Q, and R are not necessarily movable. That is, it can move from P to Q and from Q to R, but the position of the nth arm sub-reference point when moving from P to Q is in one region, and the nth arm when moving from Q to R When the position of the sub reference point is in another area, the sub reference point of the nth arm cannot be moved from one area to another area. Therefore, in the present invention, as described in claim 3 , the concept of a copy grid point is introduced so that the one region and the other region are each a holdable posture set at a different point of the n-th arm. The holdable posture set is prevented from being divided. The grid point and the copy grid point are on the same position coordinates, and the n-th arm having a reference point at each point has its sub-reference point position at an arbitrary position included in the corresponding holdable posture set. Can be moved.
When the holdable posture set of the n-th arm is divided into, for example, three, in addition to the lattice points, two copy lattice points are created on the same position coordinates as the lattice points, and the three regions are Corresponding to each, it is distributed to a lattice point and two copy lattice points.

Whether or not the holdable posture set of the nth arm is divided into a plurality of pieces is determined by, for example, setting a set of positions of sub-reference points of the nth arm with one lattice point as a fulcrum as described in claim 4. And the position of the sub reference point in a posture where the n-th arm interferes with the obstacle is excluded from the set, and the set of sub reference point positions is divided into two or more consecutive sets. It can be determined that the holdable posture set of the n-th arm is divided into a plurality of pieces by the obstacle.

  To move from the grid point of the n-th arm reference point to the copy grid point, first, the n-1 connectable point is connected from the grid point and the n-1 connectable point is connected from the copy grid point. The n-th arm reference point is moved once to a lattice point where the points are the same (copy), and then the reference point is returned to the position of the copy lattice point. As a result, the sub-reference point of the n-th arm can be moved to a point in the holdable posture set corresponding to another copy grid point.

When the sub-reference point of the nth arm is moved from one position to the target position based on the n connectability relation table, there may be a plurality of other positions that can be moved next. In this case, the position to be moved can be uniquely determined by giving a certain condition in advance. For example, as described in claim 5, when the n-th arm sub-reference point at one position is movable to a plurality of other positions, the distance from each point to the target point is calculated and calculated Another posture to be moved next may be determined based on the distance.

Some obstacles move in relation to the movement of the robot arm. For such an obstacle, as described in claim 6 , the movement of the obstacle is added to the holdable posture set table and the n connectable relationship table.
In addition, the movable range of the nth arm may be limited by the (n-1) th arm. For example, the n-th arm and the (n-1) -th arm interfere with each other in a certain area. Further, the rotation angle of the arm may be limited within a range of less than 360 degrees depending on the type of the motor or the rotation cylinder of the joint portion provided at the reference point. In such a case, as described in claim 7 , the holdable posture of the n-th arm from the allowable rotation angle of the n-th arm with respect to the posture of the (n-1) -th arm and the position of other obstacles. Create a set table and a connectable relationship table.

Said method is realizable by the route creation apparatus of Claims 8-11.
The apparatus according to claim 8 represents a work space in which the robot moves as a set of lattice points including a plurality of spaced points and a region obtained by dividing the work region according to the number of points. A robot path creation device for creating a movement path of an articulated robot having a plurality of arms N (N ≧ 1) in the virtual work space, wherein N (N ≧ 1) pieces provided in the robot For each of the arms, a posture calculation unit for determining the posture of each of the arms from the position information of the reference point on one end serving as a fulcrum of movement of the arm and the position information of the sub-reference point on the other end, and this posture For the n-th (N ≧ n ≧ 1) arm among the N arms, the obstacle interference determination unit that determines whether the posture obtained by the calculation unit interferes with the obstacle in the work space, This is the fulcrum for the movement of the nth arm. The posture indicated by the position of the reference point at the end and the position of the sub-reference point on the other end side, and with respect to the Nth arm, the posture that does not interfere with the obstacle existing in the work space is set as a holdable posture. , N belonging to the 1st to (N-1) th are at least one posture that does not interfere with an obstacle existing in the work space and can be held by the n + 1 arm located ahead. Is defined as the holdable posture of the nth arm, and a set of the holdable postures for each arm with a predetermined lattice point as a reference point is created for each of the first to Nth arms. Based on the holdable posture set table creation unit and the holdable posture set table, when the sub-reference point is movable between adjacent lattice points without the arm interfering with an obstacle, the two lattice points are N connectable pairs When the sub reference point is located at the same lattice point or when the lattice point pair where the sub reference point is located is in the n connectable relationship, the arm is adjacent without interfering with an obstacle. The grid point pair of the reference point is defined as having an n-1 connectable relationship, and each of the N arms from the Nth arm to the first arm is possible. A connectable relationship table creating unit that creates a connectable relationship table that is a set of connective relationships, and a reachability determination that determines whether or not the sub-reference point of the Nth arm can reach the target point from the connectable relationship table And the first arm in a predetermined initial posture using the holdable posture set table and the connectable relationship table when it is determined that the sub-reference point of the N-th arm can reach the target point. Standards up to the Nth arm And secondary reference point is configured to have a path generation unit to determine the route to move to the target point of each arm through the lattice points in the variable connection relationship.

According to this configuration, the posture calculation unit obtains the posture of an arbitrary n-th arm from the position of the reference point and the position of the sub reference point. Then, the obstacle interference determination unit determines whether or not the n-th arm in a predetermined posture interferes with the obstacle. This determination is made for all of the first to Nth arms . Then, based on the determination result, the holdable posture set table creating unit, in the order of n = N to 1, when the n-th arm does not interfere with the obstacle and n is smaller than N, is connected to this. An nth arm holdable posture set table having at least one holdable posture of the n + 1 arm is created. In addition, the connectable relationship table creation unit sets N adjacent connectable lattice points that do not interfere with an obstacle for n = N, and two adjacent lattice points P for other n. The n connectable relationship table is created by making P-1 and Q connectable n-1 when the holdable posture set table of the nth arm in Q and Q includes the same grid point or n connectable adjacent grid points. To do.

When each arm reference point or sub-reference point target point is designated, it is set as a position (arm target point) to be reached. The n reachability which is a set of points connectable via a lattice point in a work space that is n connectable from a predetermined initial position by querying the connectable relation table as recited in claim 9 a set, from the first arm determined for each of the n arm, in each arm each of the n reachable point set obtained, whether can reach the target point from whether the target point of the arm is contained You may comprise so that it may have a judgment part which judges these. Then, when the determination unit determines that it is reachable, the movement path creation unit, for example, moves the first arm to the Nth arm in order from the first arm based on the connectable relationship table and the sub-reference. A path is created by moving at least one of the points one by one to adjacent grid points.

The apparatus according to claim 10 determines whether or not the holdable posture set of the n-th arm having one lattice point as a fulcrum is divided into a plurality of parts having n connectable relationships by an obstacle. If it is determined that the divided points are divided, the number of copied lattice points corresponding to the number of divided points is set on the same coordinates as the lattice points, and the meaning of each n connectable state of the holdable posture set And a copy grid point creation unit for assigning the grid points and the copy grid points to the connected areas.
According to this configuration, based on the holdable posture set table of the nth arm, the copy grid point creation unit determines that the holdable posture set of the nth arm is divided into a plurality by the obstacle, and is divided. Copy lattice points are created according to the number of regions to be stored, and the lattice points and the copy lattice points are assigned to the regions of the holdable posture set.

When the n-th arm is moved from one posture to another posture based on the connectable relationship table, there may be a plurality of other postures that can be moved. In this case, as described in claim 11 , the other posture may be determined from the distance between each lattice point and each arm target point.

According to the present invention, when creating a route for a robot that performs a predetermined work in a two-dimensional or three-dimensional work space, it is possible to create a route with a relatively small amount of calculation. can do. That is, in the conventional method of automatically obtaining the movement path, when the number of arms is N and the work area of the manipulator is discretized into M lattice points, calculation and storage of an amount proportional to ^MN is performed. Although capacity was necessary, in the present invention, it is possible to create a movement path by carrying the above-described holdable posture and connectable conditions at M lattice points existing in the work space. A route can be created with a calculation amount of NM ² order and a storage amount of NM order at the maximum, and it is possible to reduce the calculation load and greatly reduce the route creation time. In addition, since the route is created based on the lattice point information that allows the arm to be continuously moved, a backtrack does not occur during the route creation process.
The present invention can be applied to a robot having a single arm, but is particularly effective for creating a route for a manipulator having three or more arms. Further, the present invention is not limited to a fulcrum fixed type robot in which the fulcrum of the first arm is fixed, but can also be applied to a fulcrum movement type robot that can move the fulcrum.
Further, in the present invention, the one end side which is the fulcrum of the movement of the nth arm is used as a reference point, and the other end side of the nth arm is used as a sub reference point. can get.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
In the following description, it is assumed that a space where the robot actually works is represented by a grid coordinate system, and a plurality of arms (arm numbers 1, 2,...) Operating in this work space are assumed. Suppose a manipulator having n-1, n, n + 1.
First, definitions of terms in this specification will be described.

(1) Arm reference point and sub-reference point Of both ends of any nth arm, the fulcrum (point that does not move even if the nth arm is moved) side is called the “reference point” of the nth arm and its coordinates The position is represented by a symbol with “S”. Further, the other end side is referred to as a “sub-reference point” of the n-th arm, and the coordinate position is represented by a symbol with “E”. Note that the “reference point” of the n-th arm is the sub-reference point of the (n−1) -th arm, and the “sub-reference point” of the n-th arm is the reference point of the (n + 1) -th arm.

(2) Position and posture of the arm The position of an arbitrary n-th arm is represented by the position (coordinate position) of the reference point, and the posture of the n-th arm is represented by a set of the position of the reference point and the sub-reference point.
For example, the reference point of the n-th arm is at an arbitrary position S _nk (the subscript “n” indicates an arm number and k indicates the number of a lattice point), and the sub-point of the n-th arm having this position S _nk as a fulcrum. The reference point is at the position E _{(nk) r} (the subscript number (nk) in parentheses designates the reference point position (S _nk ) as a pair, and r outside the parentheses indicates the number of the sub reference position) time, the position of the n arms are represented by position _{S nk} of the reference point, the position, the reference point position _{S nk} and secondary reference point position _{E (nk)} pairs and _r in _{(S nk, E (nk)} r) It shall represent.
Each of the positions S _nk and E _{(nk) r} includes a two-dimensional or three-dimensional coordinate component. For example, in the two-dimensional work space, S _nk is (X (S _nk ), Y (S _nk ). )), E _{(nk) r} = (X (E _{(nk) r} ), Y (E _{(nk) r} )).

(3) Arm _holdable posture The posture of the Nth arm located at the tip of the manipulator is defined as above when the reference point is at an arbitrary position S _Nk and the sub reference point is at the position E _{(Nk) r.} Accordingly, it can be expressed by (S _Nk , E _{(Nk) r} ). Then, this posture _{if (S Nk, E (Nk)} r) does not interfere with the obstacle, the object the position _{(S Nk, E (Nk)} r) is located in the target point in such end of the robot hand of the N arm An object can be held, which is referred to as “the Nth arm holdable posture”.
As for the n-th arm belonging to the N-1 th from the first, it is there posture the n arms in _{(S nk, E (nk)} r) does not interfere with the obstacle, and, to the n arms When the n + 1th arm connected at the sub-reference point has at least one holdable posture as described above, the posture of the nth arm (S _nk , E _{(nk) r} ) is said to be a “ _holdable posture”.

(4) Set of _holdable postures A set of sub-reference point positions E _{(nk) r in} the “ _holdable posture” of the nth arm having a reference point at the position _Snk is set as “ _holdable” of the nth arm at the position _Snk . It is referred to as “attitude set” and is represented by A (S _nk , n). In addition, all the “holdable posture sets {A (S1k, 1), A (S2k, 2),... A (S _Nk , N)” ”from the first arm to the Nth arm are stored in this manipulator. “A set of postures”, represented by A.

(5) two attitude of the n arms are continuous postural possible orientation of the n arms _{(S nk, E (nk)} r), when expressed in _{(S nk + 1, E (} nk + 1) r + 1), the reference The position of the point (S _nk , S _{nk + 1} ) and the position of the sub-reference point (E _{(nk) r} ,
If E _{(nk + 1) r + 1} ) coincide with each other or are adjacent positions on the lattice point, these two postures (S _nk , E _{(nk) r} ), (S _{nk + 1} , E _{(nk + 1) r + 1} ) It ’s continuous. ”

(6) Connectable relationship
Assuming one grid point where the sub-reference point is located and another grid point adjacent to the N-th arm (position (E _Nk , E _{Nk + 1} )), the N-th arm _serves as an obstacle. When the position of the sub-reference point can be moved to the other lattice point without interference, the two lattice point pairs having the above relationship and included in the holdable posture set are expressed as “N It is said that it is in a “connectable relationship”. Further, on the assumption that the sub-reference point of the N-th arm is located at the same lattice point or is in an N-connectable relationship, one lattice point where the reference point is located with respect to the reference point of the N-th arm And another lattice point (position (E _Nk , E _{Nk + 1} )) adjacent thereto , the position of the reference point can be determined without the N-th arm interfering with an obstacle. When the point can be moved to a point, the lattice point pair included in the holdable posture set is said to be in the “N-1 connectable relationship”. The n-th arms belonging to the first to (N-1) th can be defined in the same manner, and are referred to as "n connectable relationship" and "n-1 connectable relationship".
The above-mentioned “N connectable relationship”, “N-1 connectable relationship”, “n connectable relationship” and “n−1 connectable relationship” are shown in FIGS.

(7) Reachable point set It can be seen from the above-described n-1 connectability relationship and n connectability relationship how far the n-th arm in a predetermined initial posture can move. Therefore, a set of lattice points that can be reached from the initial posture via lattice points where the sub-reference point of the n-th arm (1 ≦ n ≦ N) is n connectable is referred to as an n reachable point set, and R (n ).

Next, a procedure for creating grid point information included in the work space will be described with reference to the flowchart of FIG.
It is assumed that the position information of the obstacle in the work space, the number of arms, the length of each arm, and the information regarding the rotation angle are stored in advance in a storage unit such as a memory or a hard disk.

First, an N connectable relationship table C (N) composed of a set of lattice points (position coordinates) in an N connectable relationship is created from the obstacle position information (step S1).
A procedure and an example of creating this N connectable relationship table C (N) will be described with reference to FIG.

FIG. 2A is a diagram illustrating the N connectable relationship.
As described above, “N connectable” means that, on the assumption of any two adjacent lattice points with respect to the sub-reference point of the Nth arm, the two lattice points do not interfere with an obstacle. To do.

  As shown in FIG. 2A, since the lattice points at the positions E1 and E2 are adjacent to each other and do not interfere with the obstacle, these lattice points are in an N-connectable relationship. Similarly, adjacent lattice points at positions E2 and E3, adjacent lattice points at positions E3 and E4, and adjacent lattice points at positions E4 and E5 are also N-connected. Here, when the reference point of the Nth arm is at the lattice point at the position S1, E1 and E2, E2 and E3, E3 and E4, and E4 and E5 are N connectable, so that the Nth arm has its sub reference. The point can be moved to E1, E2, E3, E4, E5.

  Accordingly, the N connectable relationship table C (N) can be expressed as C (N) = {(E1, E2), (E2, E3), (E3, E4), (E4, E5)}. . According to this N connectable relationship table C (N), it can be seen that when the reference point of the Nth arm is at the position S1, the starting position is E1, and the sub reference point can be moved to E5 via E2-> E3-> E4.

Next, the variable n representing the arm number is set to the maximum number N of arms (step S2). First, a reachable point set R (N) is obtained for the Nth arm (step S3).
For the first N-th arm, a position (reachable point) that the sub-reference point of the N-th arm can reach via the N-connectable grid points is obtained from the above-described N-connectable relationship table C (N). be able to. For example, if the initial position is E1, as shown in FIG. 2 (a), E1 can connect N connectable grid points as E2 → E3 → E4 → E5, and R (N) has at least E1. , E2, E3, E4, E5.

Next, for the Nth arm, a holdable posture set table A (N) that is a set of holdable postures is created (step S4).
With respect to the first N-th arm, the “holdable posture” is based on the condition that it does not interfere with an obstacle. Therefore, for each of the lattice points S1, S2, S3. The holdable posture set A (N) can be obtained from the N connectable relationship table C (N).

Next, a procedure for creating the holdable posture set A (n) for any n-th arm other than N will be described with reference to FIG.
FIG. 3A is a diagram illustrating a procedure for creating a holdable posture set table, and FIG. 3B is a diagram illustrating an example of a holdable posture set table.
As shown in FIG. 3A, for any n-th arm, when its reference point is at the position (grid point) S _n1 , its posture is (S _n1 , E _{( n1) 1} ), ( _Sn1 , E _{(n1) 2} ),..., ( _Sn1 , E _{(n1) 5} ).

Note that the sub-reference point of the n-th arm with the position S _n1 as a fulcrum also exists on the opposite side of the illustrated obstacle, but here, for convenience of explanation, the positions E _{(n1) 1 to} E _{(n1 )} indicates to _5, not shown for the remaining ones.
Here, with respect to the nth arm, it is determined for each reference point position S whether the posture of the nth arm does not interfere with the obstacle, and the nth arm does not interfere with the obstacle, and the sub reference point position. A holdable posture set A (S, n), which is a set of postures in which the (n + 1) th arm having a reference point at least has a holdable posture, is created.

Thus, when the reference point is at the position S _n1 for the n-th arm, the postures (S _n1 , E _{(n1) 1} ), (S _n1 , E _{(n1) 2} ), (S _n1 , E) of the n-th arm _{(N1) 3} ), ( _Sn1 , E _{(n1) 4} ), ( _Sn1 , E _{(n1) 5} )... _Are obtained, of which the posture ( _Sn1 , E _{(n1) 5} ) is As shown in FIG. 3 (a), the n-th arm interferes with the obstacle, so this posture is excluded from the obtained postures.

Thereby, the holdable posture set table A (n) that is a set of holdable postures for the n-th arm can be created. For example, when the reference point is at the position S _n1 , A (S _n1 , n), which is one component of the _holdable posture set table A (n), is (E _{(n1) 1} , E _{(n1) 2} , E _{( n1) 3, E (n1)} 4, can be expressed as ...) (see Figure 3 (b)). The holdable posture set table A includes holdable posture set tables A (1) to A (N) for all of the first to Nth arms.

  In the next step S5 (see FIG. 1), it is determined whether or not the holdable posture set table A (N) is divided into a plurality of pieces for the Nth arm. Whether or not the holdable posture set table A (N) having a reference point at a certain position is divided into a plurality of pieces can be determined from the connectable relationship table C (N). For example, if C (N) shown in FIG. 2A includes (E1, E2), (E2, E3), (E4, E5) but does not include (E3, E4), the holdable posture set A (S1, N) is divided between position E3 and position E4, and has two components.

In this case, a copy lattice point is created at the same position as the lattice point where the reference point of the Nth arm is located (the lattice point at the position S1 in the above example) according to the number to be divided by the method described in detail later. (Step S6).
Then, in consideration of this copy grid point, the holdable posture set table A (N) is rewritten as described later (step S7).

  For the above steps S5 to S7, details of the determination as to whether or not an arbitrary nth arm is divided into a plurality of holdable posture sets A (n) of the nth arm by an obstacle or the like will be described with reference to FIGS. This will be described with reference to FIG. Here, it is assumed that the adjacent lattice point pairs not occupied by the obstacles in FIG. 4 are already required to be “n + 1 connectable”.

Movable range of the secondary reference point of the n arms that the position S _n1 and fulcrum, if there is no obstacle in the working space, as shown in FIG. 4 _(a), E _(n1 positions S _n1 as the fulcrum _{) 1 to} E _{(n1) m + 1} .
However, since an obstacle actually exists in the work space, the movable range of the sub-reference point with the position S _n1 as a fulcrum is E _{(n1) as} shown in FIGS. _{1 to} E _{(n1) 4} and E _{(n1) k to} E _{(n1) m + 1} . Thus, for example, can hold the posture set table _{A (S} n1, n), in the sense of n + 1 Allowed _connection, and that continuously until the _{(S n1, E (n1)} 1) (S n1, E (n1) m + 1) should _{not, (S n1, E (n1} ) 1) ~ and components _{(S n1, E (n1)} 4), (S n1, E (n1) k) ~ (S n1, E (n1) m- ₁ ) It will be divided into two components.

Accordingly, the movable region of the n-th arm sub-reference point with the position S _n1 as a fulcrum includes _holdable postures (S _n1 , E _{(n1) 1} ) to (S _n1 , E _{(n1) 4} ). It can be seen that the region I is divided into the region II including the _holdable postures ( _Sn1 , E _{(n1) k} ) to ( _Sn1 , E _{(n1) m-1} ).

By the way, when the holdable posture set is divided into the region I and the region II, even if the reference point of the n-th arm is movable to adjacent points, for example, from _Sn1 to _Sn2 and _Sn2 to _Sn3 The n-th arm cannot always shift from the position of the reference point to the position S _n1 to the position of the position S _n2 and the position S _{n3 because} of the relationship with the obstacle. Causes backtracking in the process of calculating the path of the arm.
Therefore, in the present invention, when the holdable posture set is divided into a plurality of pieces as described above, the same set according to the number of divided areas (two areas I and II in this example). Another grid point is copied on the coordinates, and another grid point is assigned to each region (step S6).

This will be described in accordance with the example of FIG. 4, for the region of the holdable posture set in _{S n1} of the n arms _{I (S n1, E (n1} ) 1) ~ (S n1, E (n1) 4), As shown in FIG. 4B, the position S _n1 is assigned, and the _holdable posture set region II (S _n1 , E _{(n1) k} ) to (S _n1 , E _{(n1) m−1} ) As shown in FIG. 4C, S _n1 ′, which is a copy of S _n1 provided at the same position as the position S _n1 , is assigned. Hereinafter, the copied grid points are referred to as “copy grid points” in distinction from the original grid points, and “′” is added to the reference numerals in the figure.

Here, the holdable posture set table A (S _n1 , n) is rewritten in consideration of the copied position S _n1 ′ (step S7).
This is shown in the holdable posture set table of FIG. For example, the n arms capable of holding attitude _sets, A _(S n1, _n) having a reference point to position _{S n1 = (E (n1)} 1, E (n1) 2, E (n1) 3, E (n1) ₄ ...). Further, the _holdable posture set of the nth arm having the reference point at the position copied to the position S _n1 ′ is A (S _n1 ′, n) = (E _{(n1) k} , E _{(n1) k + 1} ,. ., E _{(n1) m-1} ...

When the holdable posture is not divided into a plurality of positions, the process jumps from step S5 to the next step S9.
In step S9, an n-1 connectable relationship table is created.
When the lattice points adjacent to each other and the holdable posture set of the N-th arm at the two points include a common lattice point or lattice points that are N-connected to each other as the sub-reference point position of the N-th arm, Let these two points be N-1 connectable. Similarly, when n is smaller than N, the n-1 connectable relationship can be obtained from the n connectable relationship.
After completing the above procedure, n = n−1 is set in step S10, and if n = 0 is not satisfied, the process returns to step S3 (step S11).

The reachable set table R (N-1) of the sub-reference point of the N-1th arm can be created from the N-1 reachable relation table C (N-1) (see FIG. 2C).
Next, a holdable posture set table A (N-1) is created for the N-1th arm. Since the position of the sub-reference point at this time should be included in the N connectable relationship table C (N), the Nth N target for creating the holdable posture set table A (N−1) using this is used. The grid points where the reference point of the -1 arm can be located can be narrowed down.

Similarly to the above, it is determined whether or not the holdable posture set table A (N-1) is divided into a plurality of pieces (step S5), and if divided, copy lattice points are set (step S6). The holdable posture set table A (N-1) is rewritten (step S7).
In the N-1th arm, lattice points adjacent to each other and the holdable posture set of the N-1th arm at the two points are used as a common reference point or a mutual reference point position of the N-1th arm. When including lattice points in the N-1 connectable relationship, these two points are set as N-2 connectable.
In this manner, the holdable posture set table A, the reachable point set table R, and the connectable relationship table C are created for all of the Nth to first arms while reducing the variable n one by one.
This completes the creation of grid point information.

Next, a procedure for creating a route using the grid point information created according to the above procedure will be described with reference to the flowchart of FIG. 6 and the route creation diagram of FIG.
For convenience of explanation, only the case of two arms is shown and described.
First, simultaneously with the start, it is determined whether or not the manipulator can reach the target posture (step S21).
This determination is based on the reachable point set R (n) created for the _n- th arm and the holdable posture set A of the n-th arm when the reference point of the n-th arm is positioned at the target point On _-1 ( O _{n-1, n)} is can be done by checking whether including the target point O _n of secondary reference point of the n arms.
If the n-th arm of the reachable point set R (n) or the n-th arm of the holdable posture set A (O _{n-1, n)} does not include the target point O _n is determined that the unreachable target posture To finish the process. (Step S21).

When the manipulator can be moved to the target posture, first, the variable n is set to 1 (step S22). If the reference point of the first arm is fixed, the path of the reference point of the first arm is set to a lattice point sequence L (0) consisting only of the target point O ₀ of the first arm reference point (step S22).

For an arm with n> 1, the path L (n) of the nth arm sub-reference point is obtained based on L (n−1).
The first point of L (n) is the initial position S _{n1 of} the n-th arm sub-reference point, and this position is the current position CP (step S23). Then, as L (n−1), the lattice point after the initial position S ₁ (= O _n−1 ) of the _n- th arm reference point in the already obtained n−1 connectable relationship is represented by a variable m (m = 1). , 2, 3,...) (Step S24).
First, when m = 1, it is determined whether or not the _first point S _{m of} L (n−1) (Sm = 1 in this case) matches On ₋₁ (step 25).
If they do not match, then the m + 1st point of L (n−1) is set to S _{m + 1} (in this case, S _{m = 2} ) (step S26), and the positions of the reference points are S _{m = 1} and S _{m = 2.} The holdable posture set A (S _{m = 1} , n) of the n-th arm and the holdable posture set A (S _{m = 2} , n) are searched (step S27), and they are coincident or n connectable to each other. It is determined whether there is a pair of points (E _cmk , E _{cm + 1k} ). If such a pair (E _cmk , E _{cm + 1k} ) is not found as a result of the search, it is determined that the movement is impossible, and the process is terminated. (However, such a case does not occur if processing is performed correctly.)
As shown in FIG. 7, if such a pair (E _cmk , E _{cm + 1k} ; in the example shown, E _cmk = E _c11 , E _{cm + 1k} = E _c12 , the two match) Since (S _m , n) and A (S _{m + 1} , n) are connected in the meaning of n connectable, each of the n connectable points from the current position CP to E _c11 in A (S _m , n). column _{(CP, E m11, E m12} , ···, E c11) exist, also it is possible to shift _{E c11} and _{E c12} is also n friendly connected together. Therefore, this sequence of points (E _m11 , E _m12 ,..., E _c11 ) and E _c12 are added to L (n), and the current position CP is replaced with E _c12 (step 28), and 1 is set to m. In addition (step S29), the process returns to step 24.
At this time, the posture columns (S _m , CP), (S _m , E _m11 ), (S _m , E _m12 ),..., (S _m , E _C11 ), (S _{m + 1} , E _C12 ) are mutually connected. It is movable, and the reference point of the n-th arm is moved from S _m to S _{m + 1} , and the sub-reference point is moved from CP to E _C12 .

Next, if S _m matches On _{-1 in} step 24, the reference point of the n-th arm has already reached the target point, so the n-th arm sub-reference point is changed from the current position CP to the sub-reference point. moving the target point _{O n} (step S30).
This process can be performed as follows. That is, since the n arms of _{O n-1} = _{S m} can be held in the posture set table _{A (O n-1, n} ) comprises _{O n,} also it is connected by means of n-friendly connection, A _{(O n -1,} n) in the current position CP from _{O n} to reach each other n-friendly connection column point _{(CP, E m11, E m12} , ···, so that _{the O n)} is present. Thus, the sequence of points _{(E m11, E m12, ···} , O n) is added, the L (n) (step S30), the column of orientation _{(O n-1, CP)} , (O n-1, _{E m11), (O n-} 1, E m12), ···, (O n-1, O n) is moveable with respect to each other, of the n arms having a reference point to _{O n-1} sub reference point it is not able to move to the target point O _n from CP.
By performing the above processing for all arms of n = 1 to n = N, a manipulator path can be created.

In the above description, a manipulator having two arms, the first arm 1 and the second arm 2, has been described as an example, but the same applies to a manipulator having three or more arms. In the above description, the reference point of the first arm 1 (the fulcrum of the position S ₀₁ ) is not moved. However, the same applies when the reference point is moved.

FIG. 8 is a block diagram illustrating an example of a device for executing the above-described route creation method and explaining its configuration.
The route creation device 1 specifies a work space, a position of an obstacle, various information about individual arms constituting the robot (arm length, allowable rotation angle range of each arm, number of arms, etc.) Based on an input unit 11 such as a keyboard for inputting final target points, a CPU 13 for processing various input information, a grid point information creating unit 15 for creating grid point information, and the created grid point information. Necessary for creating the route creation unit 16 for creating the route of the robot, and the grid point information such as the holdable posture set table, the n connectability relation table, the reachable point table, the n-1 connectability relation table, and the like. And a database DB for storing various data.

  The lattice point information creation unit 15 obtains the posture calculation unit 151 for obtaining the posture of the n-th arm from the position of the reference point and the position of the sub-reference point for an arbitrary n-th arm, and the posture calculation unit. The obstacle interference determination unit 152 that determines whether the posture of the nth arm interferes with an obstacle in the work space, and the holdable posture of the Nth arm, the Nth arm exists in the work space. The posture in which the n-th arm (1 ≦ n ≦ N−1) can be held is such that the n-th arm does not interfere with the obstacle existing in the work space and the n-th arm A holdable posture set table creation unit 153 that creates a holdable posture set table composed of these postures as a posture in which the (n + 1) th arm having the sub-reference point as a fulcrum has at least one holdable posture; It is determined whether or not the movable area of the n-th arm with the quasi-point as a fulcrum is divided into a plurality by the obstacle. A copy grid point creation unit 154 that sets the number of copy grid points corresponding to the number of divisions and assigns the reference point and the copy grid point for each movable region; The lattice points that are adjacent to each other and are adjacent to each other are in an N connectable relationship, and for n (1 ≦ n ≦ N−1), the n−1 connectable relationship of adjacent lattice points is used as a reference with respect to these lattice points. A connectable relationship table creating unit 155 that creates a connectable relationship table that is a set of connectable relationships for all of 1 to N by defining using the holdable posture set of the n-th arm having a point; , Each other from a predetermined initial position A reachable point table creating unit 156 that creates an n reachable point table that is a set of points connectable via grid points in a connectable work space for each of the first to Nth arms. Have.

  The grid point information creation unit 15 is shown in the flowchart of FIG. 1 for all of the first arm to the Nth arm based on the grid point of the work space, the position of the obstacle, and information on each arm stored in the database DB. In accordance with the procedure, an n connectable relationship table C (N), a reachable point set table R (n), a holdable posture set table A (n), a copy grid point, an n connectable relationship table C (n), etc. are created. And stored as grid point information in the database DB.

  The route creation unit 16 refers to the holdable posture set table and / or the connectable relationship table stored in the database DB, and determines whether or not the robot can reach the final target point. When the determination unit 162 determines that it is reachable, each of the first to Nth arms is sequentially set from the initial posture to the final target point and each arm target point based on the connectable relationship table. And a route creation unit 163 that creates a route by starting toward.

  The route creation unit 163 determines the position of the boundary where the posture of the nth arm moves from one region to another region based on the holdable posture set table and the connectable relationship table. Then, from the position of each arm target point or the final target point of the sub reference point of the n-th arm, it is determined whether or not it is necessary to move the posture of the n-th arm from one region to another region, When it is determined that the posture of the nth arm needs to be moved from one region to another region, the position of the reference point of the nth arm is moved to the boundary position.

Furthermore, when the path creation unit 163 moves the n-th arm from one posture to another posture based on the connectable relationship table, the path creation unit 163, when there are a plurality of other movable postures, the n-th arm The other posture is determined from the distance between each arm target point or the final target point.
The route created by the route creation unit 16 is output to a drive control unit (not shown) that actually drives each arm of the robot, and is also stored in the database DB. The data is output to an output unit 17 such as a printer.

Although a preferred embodiment of the present invention has been described, the present invention is not limited to the above description.
For example, in the above description, it is assumed that the nth arm can rotate 360 ° around the reference point (fulcrum) when no obstacle exists. However, in some manipulators, the rotation range of the n-th arm may be limited around the fulcrum, depending on the posture of the n-1 arm. In this case, in creating the holdable posture set table A (n) for the n-th arm, the allowable rotation angle of the n-th arm with respect to the posture of the (n-1) -th arm may be considered in addition to the obstacle.
In the above description, a two-dimensional plane work space has been described as an example, but it goes without saying that the present invention can also be applied to a three-dimensional work space. In this case, the position components of the reference point and the sub reference point may be three-dimensional.

The present invention relates to a fulcrum fixed type robot having a single arm, a fulcrum movement type robot having a single arm, a fulcrum fixed type robot having a plurality of arms, and the fulcrum of the first arm is fixed, The present invention can be applied to any fulcrum movement type robot having a plurality of arms and capable of moving the fulcrum.
In the above description, a two-dimensional plane work space has been described as an example for convenience of explanation, but the present invention can also be applied to a three-dimensional work space.

It is a flowchart explaining the procedure of the grid point information creation contained in a work space. It is a figure explaining "N connection relation", "n connection relation", and "n-1 connection relation". It is a figure which shows an example of the production | generation procedure of holdable attitude | position set A (n), and the n-th arm holdable attitude | position set table A (n). It is a figure explaining the concept for determining whether the movable area | region is divided | segmented into plurality. FIG. 4 is an example of a holdable posture set table A (n) in which the holdable posture set table A (n) in FIG. 3 is rewritten in consideration of copy grid points. It is a flowchart explaining the procedure of the route creation using lattice point information. It is a figure explaining the procedure of route creation. It is a block diagram concerning the example of the apparatus for performing said path | route preparation method, and demonstrating the structure.

Explanation of symbols

1 path creation device 11 input unit 13 CPU
15 grid point information creation unit 151 posture calculation unit 152 obstacle interference judgment unit 16 route creation unit 161 target determination unit 162 reachability judgment unit 163 route creation unit 17 output unit DB database

Claims (11)

The working space in which the robot moves, expressed as a set of lattice points formed of an area obtained by dividing the working area in accordance with the number of points and the point spaced, N number of arms (N ≧ 1) A robot path creation method for creating a movement path of an articulated robot in the work space,
Of the N arms, the n-th (N ≧ n ≧ 1) arm is indicated by the position of the reference point at one end serving as a fulcrum for the movement of the n-th arm and the position of the sub-reference point at the other end. For the Nth arm, the posture that does not interfere with the obstacle present in the work space is defined as a holdable posture, and the nth arm belonging to the 1st to (N-1) th is The position at which the n + 1 arm located at the front of the n + 1 arm does not interfere with an obstacle existing in the work space and has at least one holdable posture is defined as the holdable posture of the nth arm. Creating a set of holdable postures for each arm with a predetermined lattice point as a reference point for each of the N arms from the Nth arm to the first arm in order to obtain a holdable posture set table; ,
Based on the holdable posture set table, when the sub-reference point is movable between adjacent lattice points without the n-th arm interfering with an obstacle, the pair of these two lattice points is defined as n connectable relationship. And when the sub-reference point is located at the same lattice point or when the lattice point pair where the sub-reference point is located is in the n-connectable relationship, the n-th arm is adjacent without interfering with an obstacle. The grid point pair of the reference point is defined as having an n-1 connectable relationship, and each of the N arms from the Nth arm to the first arm is possible. Creating a connectable relationship table that is a set of connection relationships;
Using the holdable posture set table and the connectable relationship table, each arm passes through a lattice point in which the reference points and sub-reference points of the first to Nth arms in a predetermined initial posture are in a connectable relationship. Determining a route to travel to the target point of
A method for creating a route of a robot, comprising: 2. The robot path creation method according to claim 1, wherein the connectable relation table is referred to, and a set of points reachable from the predetermined initial position via the lattice points that are n connectable to each other. An n reachable set is obtained for each of the first arm to the Nth arm, and it is determined whether or not the target point of the arm is included in the n reachable point set for each obtained arm. When it is determined that the robot is included, it is determined that the robot can reach the target point, and each of the first arm to the Nth arm is moved from the initial posture toward the target posture, and a movement path is created. Robot path creation method. When the holdable posture set of the n-th arm (1 ≦ n ≦ N) having a reference point at one lattice point is divided by the obstacle into a plurality of components having n connectability, the one lattice 3. The robot path creation method according to claim 1, wherein a copy grid point is set on the same coordinates as the point. A set of sub-reference point positions of the n-th arm having a reference point at one lattice point is obtained, and the position of the sub-reference point in a posture where the n-th arm interferes with the obstacle is excluded from the set, and n When the set of positions of the sub-reference points in connection relation is divided into two or more components, it is determined that the holdable posture set of the n-th arm is divided by the obstacle, and the lattice points 4. The robot path creation method according to claim 3, wherein a copy grid point is set at the same position. When the n-th arm in one posture can move the sub-reference point or reference point to a plurality of other positions, the distance from each lattice point to the sub-reference point of the n-th arm or the target point of the reference point is calculated The robot path creation method according to claim 1, wherein a position to be moved next is determined based on the calculated distance. When the obstacle existing in the work space moves in association with the movement of at least one of the reference point and the sub reference point of the nth arm when moving from one posture to another posture, the nth 6. The robot path creation method according to claim 1, wherein movement of the obstacle is added to the holdable posture set table and the connectable relation table of the arm. When the obstacle moving in association with the movement of at least one of the reference point and the sub-reference point of the n-th arm is the (n-1) -th arm connected to the n-th arm at the reference point, the n-1 7. The holdable posture set table and the connectable relationship table of the n-th arm are created from the allowable rotation angle of the n-th arm with respect to the posture of the arm and the position of other obstacles. The robot path creation method described in 1. The work space in which the robot moves is represented by a set of grid points each composed of a plurality of spaced points and a region obtained by dividing the work region according to the number of points, and N arms N (N ≧ 1) the movement path of the multi-joint robot having, a route generation device of the robot to create in the working space,
For each of the N (N ≧ 1) arms provided in the robot, the position of the reference point on one end and the position information on the sub-reference point on the other end, which are fulcrums for movement of the arm, A posture calculation unit for obtaining each posture of
An obstacle interference determination unit that determines whether the posture obtained by the posture calculation unit interferes with an obstacle in the work space;
Of the N arms, the n-th (N ≧ n ≧ 1) arm is indicated by the position of the reference point at one end serving as a fulcrum for the movement of the n-th arm and the position of the sub-reference point at the other end. The N-th arm is a posture that can hold the posture that does not interfere with an obstacle existing in the work space, and the nth member from the first to the (N-1) -th is in the work space. Is defined as a holdable posture of the n-th arm, and does not interfere with an obstacle existing in the vehicle and has at least one holdable posture of the n + 1-th arm positioned ahead of it. A holdable posture set table creating unit for creating a set of holdable postures for each arm from the first arm to the N-th arm with a grid point as a reference point;
Based on the holdable posture set table, when the sub-reference point is movable between adjacent lattice points without the n-th arm interfering with an obstacle, the pair of these two lattice points is defined as an n connectable relationship. When the sub-reference point is located at the same lattice point or when the lattice point pair where the sub-reference point is located is in the n-connectable relationship, the n-th arm is adjacent without interfering with an obstacle. When it is possible to move between lattice points, the lattice point pair of the reference point is defined as having an n-1 connectable relationship, and each of the N arms is connectable from the Nth arm to the first arm in order. A connectable relationship table creating unit for creating a connectable relationship table that is a set of relationships;
Using the holdable posture set table and the connectable relationship table, each reference point and sub-reference points from the first arm to the Nth arm in a predetermined initial posture are passed through lattice points in a connectable relationship. A route creation unit for determining a route to move to the target point of the arm;
A robot path creation device characterized by comprising: 9. The robot path creation device according to claim 8, wherein the set of points reachable by inquiring the connectable relationship table and passing through the lattice points that are n connectable to each other from a predetermined initial position. N reachable sets are obtained for each of the first arm to the Nth arm, and the target is determined based on whether or not the target point of the arm is included in the n reachable point set for each obtained arm. An apparatus for creating a route of a robot, comprising: a determination unit that determines whether or not a point can be reached; and when the determination unit determines that the point can be reached, the route generation unit generates a route. When determining whether or not the holdable posture set of the n-th arm with one lattice point as a fulcrum is divided into a plurality of parts having an n-connectable relationship by an obstacle, The number of copy grid points corresponding to the number of divided points is set on the same coordinates as the grid points, and the grid points and the copy are connected to regions connected in the meaning of the individual n connectability of the holdable posture set. The robot path creation apparatus according to claim 9, further comprising a duplicate grid point creation unit for assigning grid points. The path creation unit, when moving the n-th arm from one posture to another posture based on the connectable relationship table, when there are a plurality of other movable postures, The robot path creation apparatus according to claim 8, wherein the other posture is determined from a distance to a target point of the n arm.

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