JP2012183593A - Electromagnetic hand, and robot system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pick workpieces stored in bulk state within a casing one by one without interruption and interference.SOLUTION: The robot system 10 includes a robot 12 picking the plurality of columnar or cylindrical workpieces W stored in bulk state within the casing C. The robot 12 includes an electromagnetic hand 18. The electromagnetic hand 18 includes: a main electromagnetic attraction part 20 electromagnetically attracting a circumferential face Wp or an end face We of the workpiece W by a first electromagnetic attraction face 20a; and an auxiliary electromagnetic attraction part 22 electromagnetically attracting the circumferential face Wp of the workpiece W by both second and third electromagnetic attraction faces 22a, 22b which are arranged at a tip 24 to form an obtuse angle or electromagnetically attracting the end face We of the workpiece W by either one of the second and third electromagnetic attraction faces 22a, 22b. The robot 12 picks each of the plurality of workpieces W in bulk state in the plurality of different electromagnetic attraction forms.

Description

  The present invention relates to an electromagnetic hand that electromagnetically attracts a workpiece and a robot system having a robot that picks the workpiece via the electromagnetic hand.

  2. Description of the Related Art Conventionally, a plurality of workpieces housed in a box in a box are automatically picked one by one by a robot. For example, in the robot system described in Patent Document 1, it is determined whether or not the hand interferes with the box or another workpiece before the hand grips the workpiece to be picked. When interference is determined, the workpiece to be picked is changed or the gripping form is changed.

JP 2010-207989 A

  By the way, when a plurality of columnar workpieces are accommodated in a boxed state in the box, there is a possibility that there is a workpiece that cannot be gripped by the hand in the robot system described in Patent Document 1. For example, the hand cannot grip a workpiece that stands upright at the corner of the box (an upright workpiece whose circumferential surface is in contact with two adjacent side walls of the box).

  As a countermeasure, the robot system described in Patent Document 1 has a configuration in which a plurality of workpieces are stirred by a robot or an operator or a box is vibrated in order to bring the workpiece into a position and posture that can be gripped by the hand. Has been.

  However, when a plurality of works are stirred by the hand, the hand or the work may be damaged. In addition, when a plurality of works are mixed by an operator, it is necessary to ensure the safety of the operator. Further, when the box is vibrated, it is necessary to provide a vibration mechanism for vibrating the box. In any case, it is necessary to interrupt the automatic picking of the work by the robot in order to bring the work in the box into a position and posture that can be gripped by the hand.

  Therefore, the present invention automatically picks up a plurality of cylindrical workpieces housed in a boxed state in a box, one by one, even if they stand upright at the corners of the box without interruption or interference. This is the issue.

In order to solve the above-mentioned problem, according to the first aspect of the present invention,
An electromagnetic hand that electromagnetically attracts a cylindrical or cylindrical workpiece,
A main electromagnetic adsorption part that electromagnetically adsorbs the circumferential surface or end surface of the workpiece with the first electromagnetic adsorption surface;
The circumferential surface of the workpiece is electromagnetically attracted by both the second and third electromagnetic attracting surfaces disposed at the tip of the electromagnet hand and at an obtuse angle with each other, or the workpiece is either attracted by the second or third electromagnetic attracting surface. There is provided an electromagnet hand having a sub electromagnetic attracting portion that electromagnetically attracts an end face.

According to a second aspect of the invention,
The electromagnet hand according to the first aspect, wherein the first to third electromagnetic attraction surfaces are arranged in one direction in order of the second, third, and first electromagnetic attraction surfaces from the tip of the electromagnet hand. The

According to a third aspect of the invention,
An electromagnet hand according to the first or second aspect is provided, wherein the first and second electromagnetic attracting surfaces are parallel.

According to a fourth aspect of the invention,
When the circumferential surface of the work is electromagnetically attracted by the first electromagnetic attracting surface of the main electromagnetic attracting part, the work is oriented so that the end face of the work is substantially directed in the parallel direction of the main electromagnetic attracting part and the sub electromagnetic attracting part. An electromagnet hand according to any one of the first to third aspects, comprising two guide surfaces arranged at an obtuse angle with each other.

According to a fifth aspect of the present invention,
A robot system having a robot for picking a plurality of cylindrical or cylindrical workpieces housed in a box in a bulky state,
The robot
The circumferential surface of the workpiece at both the main electromagnetic adsorption portion that electromagnetically adsorbs the circumferential surface or end surface of the workpiece with the first electromagnetic adsorption surface and the second and third electromagnetic adsorption surfaces that are disposed at the tip and at an obtuse angle with each other. An electromagnetic hand having a sub-electromagnetic adsorption portion that electromagnetically adsorbs or electromagnetically adsorbs the end face of the workpiece on either the second or third electromagnetic adsorption surface,
A robot system is provided in which a robot picks a plurality of workpieces in a stacked state in a plurality of different electromagnetic adsorption forms.

According to a sixth aspect of the present invention,
A workpiece position and posture detection means for detecting the position and posture of the workpiece;
All combinations of the workpiece, the height position of the workpiece, the electromagnetic adsorption form associated with the posture of the workpiece, and the posture of the robot that realizes the electromagnetic adsorption form are calculated, and a predetermined number of points is calculated for each combination. A combination scoring means to attach,
A robot system according to a fifth aspect is provided, comprising: a robot control unit that selects a combination of the highest points and causes the robot to pick a workpiece via an electromagnet hand based on the selected combination.

According to a seventh aspect of the present invention,
The combination scoring means assigns a higher score to the combination as the workpiece height position is higher, the priority set in advance in the electromagnetic attracting mode is higher, and the robot posture is more appropriate. A robot system according to an aspect is provided.

According to an eighth aspect of the present invention,
Interference determining means for determining whether or not interference with the electromagnetic hand and the robot occurs when the workpieces included in the combination are electromagnetically attracted to the workpiece in the electromagnetic adsorption form included in the combination and in the posture of the robot. ,
In the sixth or seventh aspect, the robot control means selects the combination of the highest points from the remaining combinations other than the combination determined by the interference determination means, and causes the robot to pick the workpiece based on the selected combination. The described robotic system is provided.

  According to the present invention, the electromagnet hand can electromagnetically attract each of a plurality of columnar or cylindrical workpieces housed in a box in a bulky state in any one of a plurality of different electromagnetic adsorption forms. For this reason, a robot having an electromagnetic hand automatically picks each workpiece that can take any position or posture in the box, one at a time, without interruption, without interference, and upright at the corner of the box. be able to.

The figure which shows schematically the structure of the robot system of one Embodiment which concerns on this invention. 1 is a schematic perspective view of an electromagnet hand according to an embodiment of the present invention. The figure which shows the several electromagnetic attraction | suction form from which the electromagnet hand shown in FIG. 2 differs The figure which shows the several different electromagnetic adsorption form of the electromagnetic hand shown in FIG. Diagram showing the flow for determining the picking order Diagram for explaining the combinations calculated to determine the picking order Diagram showing an example of interference The perspective view of the electromagnet hand of other embodiments concerning the present invention.

  FIG. 1 schematically shows the configuration of a robot system according to an embodiment of the present invention.

  The robot system 10 shown in FIG. 1 is configured to pick a plurality of cylindrical workpieces W stacked in a box C (overlapping in different postures) one by one and transport the picked workpieces W. Yes.

  For this purpose, the robot system 10 includes a robot 12 for picking the workpiece W, a three-dimensional vision sensor 14 for detecting the position and posture of the workpiece W in a stacked state, and a controller 16 for causing the robot 12 to pick the workpiece. Have.

  The robot 12 is an articulated robot having six joints 12a to 12f, for example, and has an electromagnet hand 18 at the tip thereof. The electromagnet hand 18 is configured to electromagnetically attract the workpiece W by generating a magnetic force after contacting the workpiece W, and to release the workpiece W that is electromagnetically attracted by stopping the generation of the magnetic force. The joints 12a, 12d, and 12f are torsional joints, and the joints 12b, 12c, and 12e are bending joints.

  As schematically shown in FIG. 2, the electromagnet hand 18 includes a main electromagnetic adsorption unit 20 and a sub electromagnetic adsorption unit 22 that electromagnetically adsorb the workpiece W.

  The main electromagnetic attracting portion 20 of the electromagnet hand 18 includes one electromagnetic attracting surface 20a (corresponding to “first electromagnetic attracting surface” in the claims).

  The sub-electromagnetic attracting part 22 of the electromagnet hand 18 has electromagnetic attraction surfaces 22a and 22b (patents) disposed at an obtuse angle with respect to the tip 24 of the electromagnet hand 18 (the end far from the electromagnet hand 18 attached to the robot 12). (Corresponding to “second and third electromagnetic attracting surfaces”). The angle between the two electromagnetic attracting surfaces 22a and 22b is in the range of 90 to 180 degrees, preferably about 120 degrees. The electromagnetic attracting surface 22a is parallel to the electromagnetic attracting surface 20a.

  As shown in FIG. 2, the electromagnet hand 18 has a tool coordinate system ΣT defined in advance. The origin Ot of the tool coordinate system ΣT is located at the center of the electromagnetic attracting surface 20a, and the Zt axis is orthogonal to the electromagnetic attracting surface 20a. The two electromagnetic attracting surfaces 22a and 22b are parallel to the Yt axis. Furthermore, the extending direction of the Xt axis is a direction in which the three electromagnetic attracting surfaces 20a, 22a, and 22b are arranged.

  In addition, the length of the electromagnetic adsorption surface 22a of the sub electromagnetic adsorption portion 22 in the Xt-axis direction is such that the workpiece W in a state where the circumferential surface is in contact with the side wall Cs of the box C is at least one of the two electromagnetic adsorption surfaces 22a and 22b. Is set to be smaller than the diameter of the end face of the workpiece W so that electromagnetic adsorption can be performed. Strictly speaking, when the circumferential surface of the workpiece W is electromagnetically attracted by both of the two electromagnetic attracting surfaces 22a and 22b, the outer end of the electromagnetic attracting surface 22a (the end opposite to the electromagnetic attracting surface 22b). And the workpiece W may be present between the outer end of the electromagnetic attracting surface 22b (the end opposite to the electromagnetic attracting surface 22a).

  In addition, “main” and “sub” in the main electromagnetic adsorption unit 20 and the sub-electrostatic adsorption unit 22 basically use the main electromagnetic adsorption unit 20, and the work that the main electromagnetic adsorption unit 20 cannot electromagnetically adsorb exceptionally. It is used in the sense that the sub-electromagnetic adsorption unit 22 is used for W.

  As shown in FIG. 3, such an electromagnet hand 18 can electromagnetically attract the work W in a plurality of electromagnetic attracting modes in which at least one of the part of the work W or the part of the electromagnet hand 18 that is electromagnetically attracted is different.

  As shown in FIG. 3 (A), the electromagnet hand 18 has an electromagnetic attracting surface 20a of the main electromagnetic attracting part 20 and a circumferential surface Wp of the cylindrical workpiece W. The end surface We of the workpiece W is Xt of the tool coordinate system ΣT. Electromagnetic adsorption can be performed while facing the axial direction.

  As shown in FIG. 3B, the electromagnet hand 18 can electromagnetically attract the end surface We of the cylindrical workpiece W with the electromagnetic adsorption surface 20 a of the main electromagnetic adsorption unit 20.

  As shown in FIG. 3C, the electromagnet hand 18 can electromagnetically attract the circumferential surface Wp of the cylindrical workpiece W with the two electromagnetic adsorption surfaces 22 a and 22 b of the sub electromagnetic adsorption unit 22.

  As shown in FIG. 3D, the electromagnet hand 18 can electromagnetically attract the end surface We of the cylindrical workpiece W with the electromagnetic adsorption surface 22 a of the sub electromagnetic adsorption unit 22.

  As shown in FIG. 3E, the electromagnet hand 18 can electromagnetically attract the end surface We of the cylindrical workpiece W with the electromagnetic adsorption surface 22 b of the sub electromagnetic adsorption unit 22.

  Returning to FIG. 1, the 3D vision sensor 14 scans a plurality of workpieces W in a stacked state, for example, by scanning laser light, and based on the reflected light from each workpiece W, the plurality of stacked workpieces W in a stacked state. About each, it is comprised so that the shape, position, and attitude | position may be detected. The 3D vision sensor 14 is also configured to detect the shape, position, and orientation of the box C.

  The three-dimensional vision sensor 14 is also configured to detect the shape, position, and posture of each of the box C and the workpiece W, for example, based on a base coordinate system ΣB that is predefined in the base of the robot 12. Yes. Furthermore, for example, the position in the base coordinate system ΣB of the center of gravity of the workpiece W that substantially coincides with the shape center of the workpiece W (a point on the central axis Wc equidistant from the two end faces We) is set as the position of the workpiece W. To detect. Furthermore, the direction in which the central axis Wc of the workpiece W extends is detected as the posture of the workpiece W.

  The three-dimensional vision sensor 14 is configured to transmit the detected shape, position, and orientation of the box C and the workpiece W to the controller 16 as data.

  The controller 16 controls the robot 12 to pick up a plurality of workpieces W in a piled state one by one to the robot 12 via the electromagnetic hand 18 and transport the picked workpieces W to different locations (not shown). It is configured to let you. The controller 16 is also configured to determine the picking order of a plurality of stacked workpieces W based on the shape, position, and posture of each of the box C and the workpiece W detected by the three-dimensional vision sensor 14. Yes.

  From here, the determination method of the picking order of the several workpiece | work W of the piled-up state which the controller 16 performs is demonstrated.

  The controller 16 is configured to determine the picking order of the plurality of workpieces W in a stacked state in consideration of the electromagnetic attraction form with respect to the workpiece W of the electromagnet hand 18.

  For this purpose, the postures that can be taken by the plurality of workpieces W in a stacked state are classified in advance, and each of the postures that can be taken by the sorted workpieces W comes into contact with the electromagnetic adsorption form of the electromagnet hand 18, in other words, the workpieces W. The posture of the electromagnet hand 18 with respect to the workpiece W at the time is preset and associated. Note that only one electromagnetic adsorption form is not always associated with the posture that can be taken by the workpieces W in a stacked state, but at least one electromagnetic adsorption form is associated.

  An example of associating the electromagnetic suction mode with the posture of the workpiece W will be described.

  First, as a premise, the electromagnet hand 18 uses the posture when the electromagnetic attracting surface 20a of the main electromagnetic attracting portion 20 is parallel to the horizontal plane and faces downward as a reference posture.

  When the workpiece W is in a posture in which the central axis Wc extends in a substantially horizontal direction (for example, the inclination of the central axis Wc with respect to the horizontal plane is smaller than 10 degrees), the following plurality of electromagnetic attraction forms are set in advance and associated with each other. Yes.

  As a first form of electromagnetic attraction, as shown in FIG. 3A, the Yt axis is centered from the reference posture so that the Xt axis of the tool coordinate system ΣT is substantially parallel to the center axis Wc of the workpiece W. The electromagnet hand 18 electromagnetically moves the circumferential surface Wp of the workpiece W with the electromagnetic adsorption surface 20a of the main electromagnetic adsorption unit 20 so that the workpiece W approaches the workpiece W in the rotated posture and the center of gravity Wg is positioned on the Yt-Zt plane. Adsorb. Many of the plurality of workpieces W housed in the box C in a stacked state have a posture in which the central axis Wc extends in a substantially horizontal direction. The

  Further, as a second electromagnetic adsorption mode, as shown in FIG. 3C, the Xt axis is changed from the reference posture so that the Yt axis of the tool coordinate system ΣT is substantially parallel to the center axis Wc of the workpiece W. The electromagnet hand 18 moves the circumferential surface Wp of the workpiece W on the two electromagnetic adsorptions of the sub electromagnetic adsorption unit 22 so that the workpiece W approaches the workpiece W in a posture rotated around the center and the center of gravity Wg is located on the Xt-Zt plane. Electromagnetic adsorption is performed on the surfaces 22a and 22b. With this electromagnetic adsorption form, the workpiece W in a state where the central axis Wc extends substantially horizontally and the circumferential surface Wp is in contact with the side wall Cs of the box C can be picked via the electromagnet hand 18. It becomes possible.

  Furthermore, as a modified form of the first electromagnetic adsorption form (third electromagnetic adsorption form), the Xt axis of the tool coordinate system ΣT is the center axis Wc of the workpiece W as shown in FIG. Rotate from the reference posture around the Yt axis so as to be substantially parallel to the workpiece W, approach the workpiece W in a posture rotated about the central axis Wc by an angle Δθx with respect to the vertical axis V, and the center of gravity Wg is Yt The electromagnet hand 18 electromagnetically attracts the circumferential surface Wp of the workpiece W with the electromagnetic adsorption surface 20a of the main electromagnetic adsorption unit 20 so as to be positioned on the −Zt plane. Note that a plurality of angles Δθx may be set, and in that case, the number of electromagnetic adsorption forms increases. For example, an electromagnetic adsorption form of Δθx = ± 5 °, an electromagnetic adsorption form of Δθx = ± 10 °, and an electromagnetic adsorption form of Δθx = ± 15 ° may be set. Due to this electromagnetic attraction, the work W whose center axis Wc extends substantially horizontally and whose circumferential surface Wp is partially covered (with respect to the circumferential direction) by another work W is transferred to the electromagnet hand 18. It becomes possible to pick through.

  In the case of the posture of the workpiece W in which the inclination of the central axis Wc with respect to the horizontal plane H is greater than 10 degrees and smaller than 45 degrees, the following plurality of electromagnetic adsorption forms are set in advance and associated with each other.

  As a fourth form of electromagnetic attraction, as shown in FIG. 4B, the Yt axis is centered from the reference posture so that the Xt axis of the tool coordinate system ΣT is substantially parallel to the center axis Wc of the workpiece W. The electromagnet hand 18 is moved so as to approach the workpiece W in the rotated posture and the Xt-axis direction distance ΔLx between the center of gravity Wg of the workpiece W and the origin Ot of the tool coordinate system ΣT becomes a predetermined value (for example, 10 mm). The circumferential surface Wp of the workpiece W is electromagnetically attracted by the electromagnetic attracting surface 20a of the main electromagnetic attracting portion 20. Note that a plurality of distances ΔLx may be set, and in that case, the number of electromagnetic adsorption forms increases. For example, an electromagnetic adsorption form of ΔLx = 10 mm, an electromagnetic adsorption form of ΔLx = 20 mm, and an electromagnetic adsorption form of ΔLx = 30 mm may be set. With this electromagnetic adsorption mode, the inclination of the central axis Wc with respect to the horizontal plane H is in an attitude larger than 10 degrees and smaller than 45 degrees, and the circumferential surface Wp is partially covered (with respect to the central axis Wc direction) by another workpiece W. It is possible to pick the workpiece W being picked up via the electromagnet hand 18.

  As a modified form of the above-described fourth electromagnetic adsorption form (fifth electromagnetic adsorption form), the Yt from the reference posture is set so that the Xt axis of the tool coordinate system ΣT is substantially parallel to the center axis Wc of the workpiece W. The workpiece W approaches the workpiece W in a posture that rotates about the axis and further rotates by an angle Δθx with respect to the vertical axis V about the center axis Wc, and between the center of gravity Wg of the workpiece W and the origin Ot of the tool coordinate system ΣT. The electromagnet hand 18 electromagnetically attracts the circumferential surface Wp of the workpiece W with the electromagnetic adsorption surface 20a of the main electromagnetic adsorption unit 20 so that the Xt-axis direction distance ΔLx becomes a predetermined value (for example, 10 mm). With this electromagnetic adsorption mode, the inclination of the central axis Wc with respect to the horizontal plane H is in an attitude larger than 10 degrees and smaller than 45 degrees, and the circumferential surface Wp is partially (with respect to the circumferential direction and the central axis Wc direction) by another workpiece W. It is possible to pick the workpiece W covered with () through the electromagnet hand 18.

  In the case of the posture of the workpiece W where the inclination of the central axis Wc with respect to the horizontal plane H is greater than 45 degrees and smaller than 75 degrees, the following electromagnetic attraction forms are set in advance and associated with each other.

  As a sixth electromagnetic adsorption form, as shown in FIG. 3E, the electromagnet hand 18 electromagnetically adsorbs the end surface We of the workpiece W with the electromagnetic adsorption surface 22 b of the sub electromagnetic adsorption unit 22. With this electromagnetic adsorption form, a workpiece W in which the inclination of the central axis Wc with respect to the horizontal plane H is greater than 45 degrees and smaller than 75 degrees, and substantially the entire circumferential surface Wp is covered by another workpiece W, Picking can be performed via the electromagnet hand 18.

  When the posture of the workpiece W is greater than 75 degrees with respect to the horizontal plane H, that is, when the workpiece W is substantially upright, the following plurality of electromagnetic attraction forms are set and associated with each other. Yes.

  As a seventh electromagnetic adsorption form, as shown in FIG. 3B, the electromagnet hand 18 electromagnetically adsorbs the end surface We of the workpiece W with the electromagnetic adsorption surface 20 a of the main electromagnetic adsorption unit 20. Preferably, the electromagnet hand 18 electromagnetically attracts the end surface We of the workpiece W so that the center of gravity Wg of the workpiece W is substantially positioned on the Zt axis of the tool coordinate system ΣT. With this electromagnetic adsorption mode, it is possible to pick the workpiece W that is substantially upright away from the side wall Cs of the box C via the electromagnet hand 18.

  As an eighth electromagnetic adsorption form, as shown in FIG. 3D, the electromagnet hand 18 electromagnetically adsorbs the end surface We of the work W with the electromagnetic adsorption surface 22 a of the sub electromagnetic adsorption unit 22. With this electromagnetic adsorption mode, it becomes possible to pick the workpiece W that is substantially upright with the circumferential surface Wp in contact with the side wall Cs of the box C via the electromagnet hand 18.

  In this way, at least one electromagnetic adsorption mode is set in advance and associated with each of the postures that can be taken by the plurality of workpieces W in the stacked state. The controller 16 holds such association information as electromagnetic adsorption form data.

  In addition, the several electromagnetic adsorption form mentioned above is an example, Comprising: This invention is not limited to these electromagnetic adsorption forms. Further, the association of the electromagnetic adsorption form with the posture that the workpiece W can take is also an example, and the present invention is not limited to this association.

  In addition, priorities are set in advance for the plurality of electromagnetic adsorption modes as described above. For example, when a workpiece W having a posture in which the central axis Wc extends in the horizontal direction is requested by an apparatus (that is, a post process) that receives the workpiece W from the robot 12 illustrated in FIG. 1, the central axis Wc is approximately in the horizontal direction. The workpiece W is electromagnetically attracted in the extended posture, and the priority of the electromagnetic attracting modes shown in FIGS. 3 (A), 3 (C), 4 (A), and 4 (B) is substantially vertical. The work W is electromagnetically attracted in a posture extending in the direction, and is set higher than the priorities of the electromagnetic attracting modes shown in FIGS. 3 (B) and 3 (D). The reason for this is that when the workpiece W is electromagnetically attracted in the electromagnetic attracting mode shown in FIGS. 3B and 3D, the posture of the electromagnet hand 18 is largely changed or the workpiece W is changed during the transfer of the workpiece W. This is necessary.

  For example, if the length of the workpiece W in the center axis Wc direction is long, as shown in FIG. 4B, the distance in the Xt axis direction between the center of gravity Wg of the workpiece W and the origin Ot of the tool coordinate system ΣT. The lower the ΔLx, the higher the priority is set for the electromagnetic adsorption mode. This is because reliable picking of the work W by the robot 12 and safe transport of the work W after picking are considered.

  The priority order of the plurality of electromagnetic adsorption forms is not limited to these reasons, and can be set in consideration of various reasons, and can be set freely. Further, the priority order of the plurality of electromagnetic adsorption forms is held in the controller 16 as electromagnetic adsorption form priority order data.

  As described above, at least one electromagnetic adsorption form (electromagnetic adsorption form data) associated with each of the postures that can be taken by the plurality of workpieces W in the stacked state, and the priority order of the electromagnetic adsorption forms (electromagnetic adsorption form) Based on the priority order data), the controller 16 determines the picking order of the plurality of workpieces W in the unstacked state through the following steps. The flow of determining the picking order will be described with reference to the flowchart of FIG. The flowchart of FIG. 5 is a flowchart for determining one work to be picked, and is repeatedly executed every time picking of one work W is completed.

  First, in step S100, the controller 16 acquires the shape, position, and orientation (data) of each of the box C and the plurality of workpieces W in a stacked state from the three-dimensional vision sensor 14.

  Next, in step S110, the controller 16 (1) the workpiece W, (2) the height position of the workpiece W, (3) the electromagnetic adsorption form associated with the posture of the workpiece W, and (4) All combinations of postures of the robot 12 that realize the electromagnetic adsorption form are calculated.

  FIG. 6 conceptually shows an example of a combination related to one arbitrary workpiece Wm included in the plurality of workpieces W in the stacked state.

  The height position zm of the workpiece Wm (for example, the Zb coordinate in the base coordinate system ΣB) is calculated based on the position of the workpiece Wm acquired in step S100.

  The electromagnetic adsorption form A associated with the posture of the workpiece Wm is based on the posture of the workpiece Wm acquired in step S100 and the electromagnetic adsorption form (electromagnetic adsorption form data) associated with the posture that the workpiece W can take. Is calculated. As shown in FIG. 6, electromagnetic adsorption forms A1 and A4, at least one electromagnetic adsorption form is calculated.

  For example, when the posture of the workpiece Wm acquired in step S100 is a posture in which the inclination of the central axis Wc with respect to the horizontal plane is greater than 75 degrees, the main electromagnetic attraction unit 20 (electromagnetic adsorption) of the electromagnet hand 18 as shown in FIG. The end surface We of the work Wm is electromagnetically attracted by the electromagnetic attraction mode in which the end surface We of the work Wm is electromagnetically attracted by the surface 20a) and the electromagnetic attraction surface 22a of the sub electromagnetic attraction portion 22 of the electromagnet hand 18 as shown in FIG. The electromagnetic adsorption form to be adsorbed is calculated.

  The posture J of the robot 12 that realizes the electromagnetic suction mode is calculated based on the shape, position, and posture of the workpiece Wm acquired in step S100 and the electromagnetic chucking mode with respect to the workpiece Wm.

  Specifically, first, based on the shape, position, and orientation of the workpiece Wm and the electromagnetic attraction form for the workpiece Wm, the position and orientation of the electromagnet hand 18 (for example, the tool coordinate system ΣT relative to the base coordinate system ΣB). Position and orientation) is calculated. Then, the posture of the robot 12 that can place the electromagnet hand 18 at the calculated position and posture of the electromagnet hand 18, that is, the joint angles of the joints 12a to 12f is calculated. In this case, as in the electromagnetic adsorption form A4 shown in FIG. 6, the postures of the plurality of robots 12 may be calculated for one electromagnetic adsorption form.

  Therefore, as shown in FIG. 6, a plurality of combinations (Wm, zm, A1, J1), (Wm, zm, A4, J2), (Wm, zm, A4, J3) are calculated in relation to the workpiece Wm. The

  Subsequently, in step S120, the controller 16 gives a predetermined score to each of all the combinations calculated in step S110.

  The number of points assigned to all the combinations related to each workpiece W is determined based on the height z of the workpiece W, the electromagnetic adsorption form A, and the posture J of the robot 12 included in the combination.

  Specifically, the controller 16 is configured to give a higher score to the combination as the height z of the workpiece W is higher and as the priority of the electromagnetic adsorption form A is higher.

  Further, the higher the validity of the posture J of the robot 12, the higher the score of the controller 16 is.

  For example, the closer the posture J of the robot 12 included in the combination is to the posture (excluding the torsional joint 12a) when the workpiece W picked up by the robot 12 is transferred to the apparatus (post-process), the controller 16 becomes closer to the combination. Give a high score. This is based on the idea that it is preferable that the posture change from when the workpiece W is electromagnetically attracted by the electromagnet hand 18 to when it is delivered to the apparatus (post process) is small. As a specific example related to this, the work W in a post-process in which the electromagnet hand 18 is in the reference posture (the posture when the electromagnetic attracting surface 20a of the main electromagnetic attracting unit 20 is parallel to the horizontal plane and faces downward). When the joint angle of the torsional joint 12d shown in FIG. 1 is closer to the origin (the state where the joint axes of the two bending joints 12c and 12e sandwiching the torsional joint 12d are parallel to each other), A high score is assigned to the posture J of the robot 12.

  Further, for example, the controller 16 gives a higher score as the posture J of the robot 12 included in the combination is a posture in which the load on the joint is smaller (that is, a posture that is not unreasonable). For example, the load (torque) applied to the bending joint 12e is different between the posture in which the link between the bending joint 12e and the torsional joint 12f as shown in FIG. 1 extends in the vertical direction and the posture in which the link extends in the horizontal direction. The former has a smaller load on the bending joint 12e.

  Further, for example, the controller 16 gives a higher score as the posture J of the robot 12 included in the combination is closer to a preset posture (picking start posture) immediately before the workpiece W picking is started. For example, as shown in FIG. 1, the robot 12 is in a state in which the electromagnet hand 18 is positioned above the center of the box C in the above-described reference posture, and the angles of the joints 12a to 12f are standard angles. The picking of the workpiece W is always started from a certain picking start posture. Therefore, as the posture J of the robot 12 when the electromagnetic hand 18 electromagnetically attracts the workpiece W is closer to the picking start posture, the time required for changing the posture becomes shorter, that is, necessary for picking one workpiece W. Cycle time is shortened.

  The validity of the posture J of the robot 12 is not limited to these reasons, and can be set in consideration of various reasons, and can be set freely.

The number of points assigned to the combination is calculated using, for example, the formula shown in Formula 1.

  P ((W, z, A, J)) indicates the score of the combination (W, z, A, J) related to the workpiece W. P (A) is a score based on the priority order of the electromagnetic adsorption mode set in advance, and is set so that the higher the priority is, the higher the score is. P (z) is a score based on the height position z of the workpiece W, and is set so that the higher the height position z (as compared to other workpieces), the higher the score. P (J) is a score based on the posture of the robot 12, and is set so that the higher the validity of the posture of the robot 12, the higher the score. The score P ((W, z, A, J)) of the combination (W, z, A, J) is calculated by the sum of these three scores P (A), P (z), P (J). .

  The formula for obtaining the combination score shown in Formula 1 is an example. For example, any of the three scores P (A), P (z), and P (J) may be weighted (for example, multiplied by a coefficient greater than 1) to calculate the combination score.

  Subsequently, in step S130, the controller 16 determines whether or not interference occurs when the workpiece W included in the combination is electromagnetically attracted in the electromagnetic adsorption form A included in the combination and in the posture J of the robot 12 ( To check.

  For example, in the combination (Wm, zm, A1, J1) shown in FIG. 6, when the electromagnetic hand 18 electromagnetically attracts the work Wm positioned at the height position zm in the posture J1 of the robot 12 by the electromagnetic attracting form A1. In addition, it is determined whether or not the workpiece W or the box C other than the workpiece Wm interferes with the electromagnet hand 18 or the robot 12.

  The determination of interference is performed on the computer based on the shape, position, and orientation data of the box C and the workpiece W detected by the three-dimensional vision sensor 14.

  Specifically, the controller 16 creates these three-dimensional models (point cloud data) based on the shapes, positions, and postures of the box C and the workpiece W acquired from the three-dimensional vision sensor 14 in step S100. To do. Subsequently, the controller 16 performs an interference check using the box C, the three-dimensional model of the plurality of workpieces W, and the three-dimensional model of the robot 12 including the electromagnet hand 18 prepared in advance. That is, when the target work W is electromagnetically attracted on the computer, for example, the electromagnet hand 18 crosses the box C as shown in FIG. 7A, or the electromagnet as shown in FIG. 7B. It is determined whether or not interference occurs such that the hand 18 intersects with another workpiece W.

  In addition, the interference determination about a combination is performed in an order from the combination with the high score | score attached by step S120. The reason is that if interference does not occur in the combination given the highest score in step S120, the workpiece W included in the combination of the highest points as it is in the electromagnetic adsorption form A included in the combination in the subsequent step and This is because picking is performed with the posture J of the robot 12 (that is, it is not necessary to perform an interference check for a combination of scores lower than the highest score).

  In step S140, the controller 16 selects a combination in which no interference occurs and the highest score is assigned, and controls the robot 12 based on the selected combination. That is, the workpiece W included in the selected combination is picked by the robot 12 via the electromagnet hand 18 in the electromagnetic adsorption form A included in the combination and the posture J of the robot 12.

  According to the present embodiment, the electromagnet hand 18 electromagnetically attracts each of the plurality of columnar workpieces W housed in the box C in a stacked state in any one of a plurality of different electromagnetic adsorption forms. be able to. Therefore, the robot 12 having the electromagnet hand 18 stands upright at the corner of the box C without interrupting and interfering with a plurality of stacked workpieces W that can take any position and posture in the box C. Even a workpiece W (a workpiece W in a state where the circumferential surface Wp is in contact with two adjacent side walls Cs of the box C) can be automatically picked one by one.

  For example, the workpiece W in an upright state in which the circumferential surface Wp is in contact with two adjacent side walls Cs of the box C, or a posture in which the central axis Wc extends in a substantially vertical direction as shown in FIG. As shown in FIG. 3D, the work W whose circumferential surface Wp is in close contact with one side wall Cs of the box C has the electromagnet hand 18 at its sub electromagnetic attracting portion 22 (electromagnetic attracting surface 22a). Picking can be performed by electromagnetically attracting the end face We of W. In addition, as shown in FIG. 3C, the work W with the central axis Wc extending in a substantially horizontal direction and the circumferential surface Wp in close contact with the box C is also provided with the electromagnet hand 18 as a sub electromagnetic attracting portion. Picking can be performed by electromagnetically attracting the circumferential surface Wp of the workpiece W with 22 (electromagnetic attracting surfaces 22a, 22b).

  Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to this.

  For example, the electromagnet hand is not limited to the shape shown in FIG.

  FIG. 8 shows an electromagnet hand according to another embodiment of the present invention. Generally speaking, the electromagnet hand 118 shown in FIG. 8 has a structure in which two electromagnet hands 18 shown in FIG. 2 are juxtaposed in the Yt-axis direction of the tool coordinate system ΣT.

  The electromagnet hand 118 includes a main electromagnetic adsorption unit 120 and a sub electromagnetic adsorption unit 122 that electromagnetically adsorb the workpiece W. The main electromagnetic adsorption unit 120 includes two electromagnetic adsorption surfaces 120a and two electromagnetic adsorption surfaces 120b. The two electromagnetic attracting surfaces 120a are on the same plane and correspond to the electromagnetic attracting surface 20a shown in FIG. The origin Ot of the tool coordinate system ΣT includes two electromagnetic attracting surfaces 120a and is located at the center of the virtual plane Pv having the minimum area, and the Zt axis is orthogonal to the virtual plane Pv.

  The two electromagnetic adsorption surfaces 120b of the main electromagnetic adsorption unit 120 intersect at an acute angle with respect to the virtual plane Pv, are parallel to the Xt axis of the tool coordinate system ΣT, and are symmetrical with respect to the Xt-Zt plane of the tool coordinate system ΣT. It is a plane. The angle of the electromagnetic attraction surface 120b with respect to the virtual plane Pv is preferably 30 degrees (that is, the angle between the two electromagnetic attraction surfaces 120b is preferably 120 degrees).

  The sub electromagnetic attracting portion 122 of the electromagnet hand 118 includes two electromagnetic attracting surfaces 122a and two electromagnetic attracting surfaces 122b. The two electromagnetic attraction surfaces 122a are on the same plane and correspond to the electromagnetic attraction surface 22a of the electromagnet hand 18 shown in FIG. The two electromagnetic attraction surfaces 122b are on the same plane and correspond to the electromagnetic attraction surface 22b of the electromagnet hand 18. The electromagnetic attracting surfaces 122a and 122b are arranged at an obtuse angle, preferably 120 degrees. The electromagnetic attracting surface 122a is parallel to the electromagnetic attracting surface 120a.

  The length of the two electromagnetic attracting surfaces 122a in the Xt-axis direction is such that the end surface We of the workpiece W can be electromagnetically attracted to the workpiece W in a state where the circumferential surface Wp is in contact with the side wall Cs of the box C. It is set smaller than the diameter.

  Furthermore, the two electromagnetic adsorption surfaces 122a and the two electromagnetic adsorption surfaces 122b of the sub electromagnetic adsorption unit 122 are parallel to the Yt axis of the tool coordinate system ΣT.

  Such an electromagnet hand 118 can electromagnetically attract the cylindrical workpiece W in various forms as follows.

  The electromagnet hand 118 can electromagnetically adsorb the end surface We of the cylindrical workpiece W with the two electromagnetic adsorption surfaces 120 a of the main electromagnetic adsorption unit 120.

  The electromagnet hand 118 has two electromagnetic attracting surfaces 120b of the main electromagnetic attracting part 120, and the electromagnetic surface with the circumferential surface Wp of the cylindrical workpiece W facing the Xt axis direction of the tool coordinate system ΣT. Can be adsorbed.

  The electromagnet hand 118 can electromagnetically attract the circumferential surface Wp of the cylindrical workpiece W by the two electromagnetic adsorption surfaces 122a and the two electromagnetic adsorption surfaces 122b of the sub electromagnetic adsorption unit 122.

  The electromagnet hand 118 can electromagnetically attract the end surface We of the cylindrical workpiece W with the two electromagnetic adsorption surfaces 122 a of the sub electromagnetic adsorption unit 122.

  The electromagnet hand 118 can electromagnetically adsorb the end surface we of the cylindrical workpiece W with the two electromagnetic adsorption surfaces 122b of the sub electromagnetic adsorption unit 122.

  As an advantage, the electromagnet hand 118 is lighter (when it has the same outer size) when compared with the electromagnet hand 18 shown in FIG.

  The electromagnet hand 118 further functions as a guide surface by two electromagnetic attracting surfaces 120b parallel to the Xt axis of the tool coordinate system ΣT. Therefore, compared to the electromagnet hand 18 shown in FIG. Electromagnetic adsorption can be performed in a state of being accurately oriented in the axial direction. Thereby, when the workpiece | work W of the attitude | position in which the end surface We turned to the Xt-axis direction correctly is requested | required by a post process, the request | requirement can be met.

  In the case of the electromagnet hand 18 shown in FIG. 2, for example, if the two surfaces are parallel to the Xt axis and an obtuse V-shaped surface is formed on the electromagnetic attraction surface 20a, the electromagnet hand 118 functionally shown in FIG. Become equivalent. In this case, the electromagnet hand 18 can be interpreted as having two V-shaped surfaces arranged in different postures when the electromagnetic attracting surfaces 22a and 22b of the sub electromagnetic attracting portion 22 are interpreted as V-shaped surfaces. .

  Further, the three electromagnetic attraction surfaces 20a, 22a, and 22b of the electromagnet hand 18 shown in FIG. 2 and the electromagnetic attraction surfaces 120a, 122a, and 122b of the electromagnet hand 118 shown in FIG. 8 are continuous. Not limited to this. For example, those skilled in the art will be able to perform electromagnetic adsorption on the circumferential surface Wp of the cylindrical workpiece W if the electromagnetic adsorption surfaces 22a and 22b shown in FIG. Is obvious.

  Further, the electromagnetic attracting surfaces 20a and 22a of the electromagnet hand 18 shown in FIG. 2 are parallel and the electromagnet hands 120a and 122a shown in FIG. 8 are parallel, but the present invention is not limited to this.

  Furthermore, in the case of the above-described embodiment, the three electromagnetic attraction surfaces 20a, 22a, and 22b of the electromagnet hand 18 shown in FIG. 2, and the electromagnetic attraction surfaces 120a, 120b, 122a of the electromagnet hand 118 shown in FIG. Although 122b is a plane, the present invention is not limited to this. In the broad sense, the electromagnetic chucking surface may be an uneven surface, for example, as long as the cylindrical workpiece can be electromagnetically chucked in the same posture (posture with respect to the electromagnet hand) as when the electromagnetic chucking surface is flat. Good.

  In addition, the present invention is applicable not only to a columnar workpiece but also to a cylindrical workpiece. The cylindrical workpiece may be hollow, and the center of gravity may be at a position different from the shape center. When the center of gravity of the cylindrical workpiece is different from the center of the shape, it is necessary to set the electromagnetic adsorption mode for the posture that the workpiece can take based on the position of the center of gravity. The present invention can also be applied to a part of a columnar or cylindrical workpiece.

  The electromagnet hand and the robot system using the electromagnet hand according to the present invention can be used for various applications because a cylindrical workpiece can be picked and conveyed in a plurality of electromagnetic adsorption forms. For example, the present invention can also be applied to a robot system that distributes cylindrical workpieces in different postures to a plurality of transfer destinations.

DESCRIPTION OF SYMBOLS 10 Robot system 12 Robot 18 Electromagnet hand 20 Main electromagnetic adsorption part 20a 1st electromagnetic adsorption surface (electromagnetic adsorption surface)
22 Sub electromagnetic adsorption part 22a 2nd electromagnetic adsorption surface (electromagnetic adsorption surface)
22b Third electromagnetic adsorption surface (electromagnetic adsorption surface)
24 Tip C Box W Work Wp Circumferential surface We End surface

Claims (8)

An electromagnetic hand that electromagnetically attracts a cylindrical or cylindrical workpiece,
A main electromagnetic adsorption part that electromagnetically adsorbs the circumferential surface or end surface of the workpiece with the first electromagnetic adsorption surface;
The circumferential surface of the workpiece is electromagnetically attracted by both the second and third electromagnetic attracting surfaces disposed at the tip of the electromagnet hand and at an obtuse angle with each other, or the workpiece is either attracted by the second or third electromagnetic attracting surface. An electromagnet hand having a sub-electromagnetic attracting part for electromagnetically attracting an end face.   The electromagnet hand according to claim 1, wherein the first to third electromagnetic attraction surfaces are arranged in one direction in order of the second, third, and first electromagnetic attraction surfaces from the tip of the electromagnet hand.   The electromagnet hand according to claim 1, wherein the first and second electromagnetic attracting surfaces are parallel.   When the circumferential surface of the work is electromagnetically attracted by the first electromagnetic attracting surface of the main electromagnetic attracting part, the work is oriented so that the end face of the work is substantially directed in the parallel direction of the main electromagnetic attracting part and the sub electromagnetic attracting part. The electromagnet hand according to any one of claims 1 to 3, comprising two guide surfaces arranged at an obtuse angle with each other. A robot system having a robot for picking a plurality of cylindrical or cylindrical workpieces housed in a box in a bulky state,
The robot
The circumferential surface of the workpiece at both the main electromagnetic adsorption portion that electromagnetically adsorbs the circumferential surface or end surface of the workpiece with the first electromagnetic adsorption surface and the second and third electromagnetic adsorption surfaces that are disposed at the tip and at an obtuse angle with each other. An electromagnetic hand having a sub-electromagnetic adsorption portion that electromagnetically adsorbs or electromagnetically adsorbs the end face of the workpiece on either the second or third electromagnetic adsorption surface,
A robot system in which a robot picks a plurality of workpieces in a stacked state in a plurality of different electromagnetic adsorption forms. A workpiece position and posture detection means for detecting the position and posture of the workpiece;
All combinations of the workpiece, the height position of the workpiece, the electromagnetic adsorption form associated with the posture of the workpiece, and the posture of the robot that realizes the electromagnetic adsorption form are calculated, and a predetermined number of points is calculated for each combination. A combination scoring means to attach,
The robot system according to claim 5, further comprising: a robot control unit that selects a combination of the highest points and causes the robot to pick a workpiece via an electromagnet hand based on the selected combination.   The combination scoring means assigns a higher score to the combination as the workpiece height position is higher, the priority set in advance in the electromagnetic adsorption form is higher, and the robot posture is more appropriate. 7. The robot system according to 6. Interference determining means for determining whether or not interference with the electromagnetic hand and the robot occurs when the workpieces included in the combination are electromagnetically attracted to the workpiece in the electromagnetic adsorption form included in the combination and in the posture of the robot. ,
8. The robot control unit according to claim 6 or 7, wherein the robot control unit selects a combination of the highest points from the remaining combinations other than the combination for which the interference determination unit has determined the interference, and causes the robot to pick a workpiece based on the selected combination. Robot system.

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