JP5927604B2 - Attitude control device for work equipment - Google Patents

Description

  The present invention relates to a posture control device for a work work device, and more particularly to a posture control device for a work work device to be mounted on a robot arm.

In a production line that processes and assembles a plurality of parts to complete a product having various variations, a technique for efficiently gripping and transporting workpieces having various shapes is adopted (for example, Patent Documents 1 and 2).
In Patent Document 1, in order to grip a workpiece stacked in a storage container, the three-dimensional shape of the workpiece is identified, and the workpiece holding means attached to the tip of the robot arm is controlled to the center of gravity coordinate position of the workpiece. Thus, the workpieces are taken out one by one and conveyed.
In Patent Document 2, a tool coordinate system is set for a robot hand, and a deviation from the initial setting of the robot hand is corrected by a three-dimensional visual sensor to correct the relative position and posture of the robot hand.

JP-A-10-315167 (Claim 1) JP-A-10-97311 (Claim 1)

  However, Patent Document 1 has a problem that it is difficult to deal with a work that cannot be stacked. Further, in Patent Document 2, there is a problem that control and operation are complicated, and it is not possible to correct a deviation in position and angle between the work gripping portion of the work gripping device attached to the robot arm and the gripped portion of the work. It was.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a posture control device for a work work device that suitably controls the posture of the work work device mounted on a robot arm with respect to the work. .

In order to solve the above-mentioned problem, the invention according to claim 1 is a work that is attached to a robot arm, engages with a work supported by a work support means, presses the work, and grips a predetermined part of the work. a posture control device of the gripping device, and a fixing plate for fixing to the robot arm, and a support plate in which the workpiece gripping device is provided, mounted between the supporting plate and said fixed plate, said support plate the has an elastic mechanism for elastically supporting and urged away with respect to the fixed plate, a posture detecting device for detecting an attitude of the workpiece gripping device relative to the workpiece, wherein the posture detecting device, said workpiece and support shaft to abut on the workpiece holding in a state where the support shaft is moved by a predetermined moving amount from the contact with the workpiece Includes a contact detection mechanism location detects the proper position near Rukoto, wherein the resilient mechanism comprises a displacement detecting means for detecting a displacement with respect to the fixed plate of the support plate, the displacement detecting means, A first detector that detects the original position of the support plate, and the support plate is moved by a predetermined amount of movement from the original position detected by the first detector, so that the workpiece gripping device is in an appropriate gripping position. And a third detector for detecting excessive displacement of the support plate, and the workpiece gripping device for the workpiece by the elastic mechanism while pressing the workpiece by the workpiece gripping device. the inclined posture by controlling the person the workpiece and the workpiece holding device so as to directly face, and the workpiece based on a detection result of the abutment detection means and the displacement detecting means It characterized that you detect that and said work gripping device is directly opposite.

The invention according to claim 1 is provided with an elastic mechanism, so that, for example, even if the workpiece placed on the pallet is deviated or inclined from a predetermined position, according to the deviation amount due to this deviation or the like. The posture of the work work device with respect to the work can be controlled.
In other words, when there is a deviation or inclination of the workpiece, the workpiece working device is placed at a predetermined position with respect to the workpiece by the robot arm, and when the workpiece working device works on the workpiece, Depending on the amount of deviation, a load is applied from the workpiece to the workpiece working device in a reactive manner.

The load applied to the workpiece working device acts on the elastic mechanism via the support plate, so that the elastic mechanism flexibly shifts the position and angle of the workpiece working device relative to the workpiece by the elastically supported support plate. By absorbing, the position and inclination angle of the support plate can be corrected according to the amount of deviation.
Thus, the posture control device according to the present invention can suitably control and correct the posture of the work work device with respect to the work.

  Here, the “robot” in the present invention is, for example, an automatic machine or an articulated robot such as a conveyance, painting, and welding robot, and the “work work device” is a gripping device, a painting device, a welding device, or the like.

In the invention according to claim 1, the posture detecting device detects that the support shaft is in contact with the workpiece, so that the workpiece gripping device is in a predetermined posture with respect to the workpiece, that is, a predetermined amount. It is possible to detect that the robot has been positioned at a predetermined grip angle at the grip position.
That is, in a state of being disposed at a predetermined position of the workpiece gripping device relative to the workpiece by the robot arm, said support shaft is in contact with the workpiece by detecting by said contact detection mechanism, wherein the workpiece holding It can be detected that the apparatus is positioned in a predetermined posture with respect to the workpiece.
Further, the present invention is provided with a displacement detection means for detecting the displacement of the support plate with respect to the fixed plate, so that when the workpiece is displaced or inclined and an excessive load acts on the workpiece gripping device. Since an excessive load acts on the elastic mechanism via the support plate, it is possible to detect an excessive displacement of the support plate with respect to the fixed plate due to the excessive load.
In addition, since the workpiece gripping device is easily affected by the positional deviation of the workpiece, it may be difficult to reliably grip the workpiece. However, when the posture control device of the present invention is applied to the workpiece gripping device, deviation or the like occurs. This is particularly preferable because the posture of the gripping device can be appropriately controlled with respect to the workpiece.
Thus, the posture control device according to the present invention detects that the posture of the workpiece gripping device with respect to the workpiece is abnormal by detecting the displacement of the support plate with respect to the fixed plate by the displacement detection means, An excessive load generated when the workpiece gripping device grips the workpiece can be detected and avoided in advance.

The invention according to claim 2 is the posture control device for the workpiece gripping device according to claim 1 , wherein the elastic mechanism is configured by a spring member or a gas spring.

According to this configuration, since the elastic mechanism is configured by a spring member or a gas spring, a sufficient stroke necessary for posture control of the workpiece gripping device can be ensured. Here, since the load of the spring member is proportional to the amount of deflection, it is suitable for applications in which the posture control force is gradually increased, and the gas spring can generate a constant load even if the amount of deflection changes. Therefore, it is suitable for applications that ensure a stable and constant attitude control force from the beginning.
Thus, the posture control device according to the present invention can realize suitable posture control of the workpiece gripping device by adopting an elastic mechanism suitable for posture control of the workpiece gripping device as appropriate.

The invention according to claim 3 is the attitude control device of a work gripping device according to claim 1 or claim 2, wherein the contact sensing means comprises a pressure sensitive means provided at the distal end of said support shaft It is characterized by that.

  According to such a configuration, it is possible to reliably detect that the support shaft is in contact with the workpiece by providing a pressure-sensitive means such as a piazo element at the tip of the support shaft.

The invention according to claim 4 is the posture control device for the workpiece gripping device according to any one of claims 1 to 3 , wherein the support shaft includes an outer cylinder in which the support shaft is retractable, and the support shaft. the characterized by comprising further a biasing means for biasing in a direction of pressing the workpiece.

According to such a configuration, by providing the biasing means for biasing the support shaft in the direction of pressing the work, the support shaft can be pressed against the work by applying an appropriate load. The support shaft can be brought into contact with the workpiece without damaging the workpiece.
In addition, by providing contact detection means for detecting that the support shaft has moved a predetermined amount of movement after contacting the workpiece, the support shaft is in contact with the workpiece and the workpiece is in contact with the workpiece. It is possible to more reliably detect that the gripping device is positioned in a predetermined posture.

The invention according to claim 5 is the posture control device for the workpiece gripping device according to claim 4 , wherein an elastic coefficient of the elastic mechanism is larger than an elastic coefficient of the urging means.

According to this configuration, by making the elastic coefficient of the elastic mechanism larger than the elastic coefficient of the urging means, for example, when the initial load is not applied or equal, the support shaft is urged by the urging means. The stroke that moves against the urging force can be made larger than the stroke that the support plate moves against the elastic force of the elastic mechanism.
For this reason, after detecting that it has moved by the predetermined amount of movement by the contact detection means, it is possible to exert the necessary elastic support force by the elastic mechanism.

The invention according to claim 6 is the posture control device for the workpiece gripping device according to any one of claims 1 to 5 , wherein the support shaft has a flexibility that comes into contact with the workpiece at a tip end thereof. A member is provided.

  According to such a configuration, for example, by providing a flexible member such as rubber, polystyrene foam, or sponge, the impact force when the support shaft is brought into contact with the workpiece is mitigated to prevent the workpiece from being damaged. be able to.

The invention according to claim 7 is the posture control device for the workpiece gripping device according to any one of claims 1 to 6 , wherein the workpiece support means is a pallet on which the workpiece is placed. It is characterized by.

The posture control device for a workpiece gripping device according to the present invention can suitably control the posture of the workpiece gripping device mounted on the robot arm with respect to the workpiece.

It is a top view which shows the workpiece carrying-out process for demonstrating the usage example at the time of applying the attitude | position control apparatus which concerns on embodiment of this invention to a workpiece holding apparatus. It is sectional drawing which shows the structure of the principal part of the attitude | position control apparatus of the workpiece | work holding apparatus which concerns on embodiment of this invention. It is a figure which shows operation | movement of the holding | grip mechanism in the workpiece | work holding apparatus which concerns on embodiment of this invention, (a) is sectional drawing, (b) is a side view of a front-end | tip part. It is a figure which shows the holding mechanism in the workpiece | work holding device which concerns on embodiment of this invention, (a) is a perspective view, (b) is the state before holding, (c) is an exploded view of a driven member, (d ) Indicates the gripped state. It is a fragmentary sectional front view which shows the structure of the positioning jig of the holding | grip mechanism in the attitude | position control apparatus which concerns on embodiment of this invention. It is a typical front view which shows operation | movement (when the rigidity of the pallet which mounts a workpiece | work is high) in the attitude | position control apparatus which concerns on embodiment of this invention (a) inserts a workpiece holding part in a to-be-held part (B) shows a state after the workpiece gripping portion is inserted into the gripped portion. It is a typical front view which shows operation | movement (when the rigidity of the pallet which mounts a workpiece | work is low) in the attitude | position control apparatus which concerns on embodiment of this invention, (a) inserts a workpiece holding part in a to-be-held part (B) shows a state after the workpiece gripping portion is inserted into the gripped portion. It is a fragmentary front sectional view for demonstrating operation | movement of the workpiece | work holding | grip apparatus which concerns on embodiment of this invention, and shows the state before holding | grip with a holding | grip apparatus. It is a partial front sectional view for explaining operation of the work grasping device concerning the embodiment of the present invention, and shows the state where the support shaft contacted the work. It is a partial front sectional view for explaining operation of the work grasping device concerning the embodiment of the present invention, and shows the state where the outer cylinder of the support shaft contacted the work. It is a fragmentary front sectional view for demonstrating operation | movement of the workpiece holding apparatus which concerns on embodiment of this invention, and shows the state which clamp was completed. It is a fragmentary front sectional view for demonstrating operation | movement of the workpiece | work holding | gripping apparatus when the workpiece | work concerning the embodiment of this invention has produced the position shift excessively.

A case where the posture control device 2 according to the embodiment of the present invention is applied to a workpiece gripping device 1 which is a workpiece working device will be described in detail mainly with reference to FIGS.
As shown in FIG. 1, the workpiece gripping device 1 is used by being attached to the distal end portion 102 of the robot arm 101 of the articulated robot 100 while being attached to the posture control device 2. The articulated robot 100 includes a workpiece gripping device 1 in which a workpiece W placed on a pallet 201 that has been transported to a take-out position by a transport device 200 is mounted on a distal end portion 102 of a robot arm 101 (see also FIG. 2). Thus, the gripping portion Wa (FIG. 2) of the workpiece W is gripped at three positions, and the robot arm 101 is turned to release the gripping state and transport the workpiece to the unloading device 300 (see the workpiece W1).

  In the present embodiment, the case where the work work apparatus is the work gripping apparatus 1 will be described. However, the present invention is not limited to this. For example, a coating apparatus that presses a sponge roller against the work and paints the work. The present invention can also be appropriately applied to a welding apparatus that performs welding while sandwiching between electrodes.

<Work gripping device>
As shown in FIG. 2, the workpiece gripping device 1 includes a gripping mechanism 11 that grips a gripped portion Wa of a workpiece W, a triaxial moving mechanism 12 that supports the gripping mechanism 11 so as to be freely movable, and a gripping mechanism 11. A movement restriction device 13 for restricting movement.
As shown in FIG. 1, the workpiece gripping device 1 includes a positioning mechanism 400 for the gripping mechanism 11 for adapting the gripping mechanism 11 to various workpieces in the vicinity of the articulated robot 100.

  In the present embodiment, the workpiece gripping device 1 is provided with three similar workpiece gripping devices 1 and grips the gripped portion Wa of the workpiece W at three locations (see FIG. 1). It is not limited to the location, and may be appropriately 1 location or 2 or more locations depending on the shape of the workpiece W. The gripping mechanisms 11 arranged at three locations have the same configuration.

  As shown in FIG. 3, the gripping mechanism 11 houses the driving member 111 in which the wedge-shaped portion 111 a is formed, the driven member 112 that moves in the diameter-expanding direction by the driving member 111, and the driving member 111 and the driven member 112. A holder 113 and driving means 114 (FIG. 2) for driving the driven member 112 by reciprocating the driving member 111 are provided.

As shown in FIG. 4B, the drive member 111 has a cylindrical shape, and is provided with a wedge-shaped portion 111a having a flat surface formed at three points in the circumferential direction at the tip portion.
As shown in FIG. 4C, the driven member 112 has a substantially rectangular shape, and is arranged at three locations side by side in the circumferential direction. The driven member 112 has a slope portion 112a formed of a flat surface that fits the wedge-shaped portion 111a on one outer surface, and a joint portion 112b that joins the gripped portion Wa on the other inner surface. .

  The gradient portion 112a is formed with a flat surface so as to fit the wedge-shaped portion 111a made of a flat surface, and the joint portion 112b is formed in an arc shape in cross section so as to fit the gripped portion Wa of the workpiece W. However, the present invention is not limited to this, and may be appropriately determined in consideration of the weight of the workpiece W, the wear resistance of the sliding portion, the difficulty of workability, and the like. For example, the gradient portion 112a and the wedge-shaped portion You may form 111a in circular arc shape by sectional view.

As shown in FIG. 3, the holder 113 has a main body portion 113a that supports the drive member 111 so as to be reciprocally movable in the vertical direction of FIG. 3A, and a front end that is screwed and joined to the front end of the main body portion 113a. Part 113b (see FIG. 4B).
The holder 113 supports the drive member 111 so as to be reciprocally movable on the inner peripheral surface 113c of the main body 113a, and the driven member 112 is supported by the support portions 113d and 113e (see FIG. 3B) of the tip 113b. It is supported so as to be capable of reciprocating in the left-right direction (horizontal direction) of (a).

As shown in FIG. 2, the driving means 114 is configured such that a reciprocating driving means such as an air cylinder is connected to the driving member 111 so that the driving member 111 can reciprocate.
The gripping mechanism 11 moves the driven member 112 in the left-right direction in FIG. 3A by reciprocating the driving member 111 in the vertical direction in FIG. )), And a mechanism for gripping the workpiece W (see FIG. 2) by pressing the joint 112b of the driven member 112 of the gripped portion Wa of the workpiece W (see FIG. 4D).

As shown in FIG. 2, the three-axis moving mechanism 12 includes an X-axis direction moving mechanism 121 disposed on the support plate 22, a Y-axis direction moving mechanism 122 supported by the X-axis direction moving mechanism 121, And a Z-axis direction moving mechanism 123 supported by a Y-axis direction moving mechanism 122 via a bracket 124.
The three-axis moving mechanism 12 is configured in the same manner as the three axes. For example, in the X-axis direction moving mechanism 121, a guide rail 121a disposed in the X-axis direction and a movable movement along the guide rail 121a are disposed. Holder 121b.
With this configuration, the workpiece gripping device 1 can be freely moved in the three-axis directions of the front and rear (X axis), the left and right (Y axis), and the vertical (Z axis) directions by the three-axis moving mechanism 12. I support it.

  In the present embodiment, the triaxial moving mechanism 12 is adopted, but the present invention is not limited to this, and the degree of freedom is appropriately set in consideration of the positional relationship of the gripped portion Wa of the workpiece W. One or two axes may be used, and a moving mechanism provided with a rotating shaft may be employed.

  The movement restricting device 13 is configured in the same manner for the three axes, and is provided in the X-axis direction moving mechanism 121, the Y-axis direction moving mechanism 122, and the Z-axis direction moving mechanism 123, respectively. For example, the X-axis direction moving mechanism 121 employs a lock mechanism that clamps the guide rail 121a and restricts the movement of the holder 121b. However, the locking method in the movement restricting device 13 is not particularly limited, and various forms such as an air type and an electromagnetic type can be adopted.

With this configuration, the workpiece gripping device 1 can be held by the movement restricting device 13 so that the gripping mechanism 11 is locked and moved in a state of being aligned with the gripped portion Wa of the workpiece W.
For this reason, the workpiece gripping apparatus 1 can flexibly handle various workpieces with different gripping positions by adjusting the gripping mechanism 11 to a free position by using an alignment jig 400 of the gripping mechanism 11 described later (see FIG. 5). can do.

<Attitude control device>
As shown in FIG. 2, the posture control device 2 includes a fixed plate 21 that is fixed to the tip 102 of the robot arm 101, a support plate 22 that supports the workpiece gripping device 1, and an elastic mechanism 3 that elastically supports the support plate 22. And a displacement detection means 4 for the support plate 22 and a posture detection device 6 for detecting the posture of the workpiece gripping device 1.

The fixed plate 21 is a member that serves as a base for supporting the support plate 22 and has a rectangular shape in plan view (see FIG. 1).
The support plate 22 is elastically supported by the fixed plate 21 via elastic mechanisms 3 (see also FIG. 1) disposed at the four corners. The support plate 22 is disposed at predetermined locations (three locations in the present embodiment) so that the workpiece gripping device 1 and the posture detection device 6 can grip predetermined locations (three locations in the present embodiment) of the workpiece W. ing.

  As shown in FIG. 2, the elastic mechanism 3 is attached to the support plate 22 in a direction away from the fixed plate 21 (downward in FIG. 2) by a coil spring 31 disposed between the fixed plate 21 and the support plate 22. Thus, the support plate 22 is elastically supported with respect to the fixed plate 21.

  In the present embodiment, the coil spring 31 is employed as the spring member of the elastic mechanism 3, but the present invention is not limited to this, and the torsion is possible as long as the load and the amount of deflection necessary for posture control can be secured. Various spring members such as a coil spring, a leaf spring, and a disc spring can be employed. Moreover, it is not limited to a spring member, A gas spring can also be employ | adopted.

  That is, according to the work content of the work work device, a suitable posture control is realized by appropriately selecting an appropriate spring member or gas spring in consideration of a load and a deflection amount (stroke) necessary for the posture control. Since the load of the spring member is proportional to the amount of deflection, it is suitable for applications that gradually increase the attitude control force, and the gas spring can generate a constant load even if the amount of deflection changes. Suitable for applications that ensure a stable and constant attitude control from the beginning.

The displacement detection means 4 is a detection device that detects the displacement of the support plate 22 relative to the fixed plate 21, and a detection device such as a proximity sensor is used.
The displacement detection means 4 includes a first detector 41 and a first detected portion 41a for detecting the original position of the support plate 22, and a second detector 42 and a second detected portion for detecting the grip position by the workpiece gripping device 1. 42a, and a third detector 43 and a third detected portion 43a that detect excessive displacement of the support plate 22.

  With this configuration, the support plate 22 moves in the direction approaching the fixed plate 21 from the original position shown in FIG. 8, and when the second detected portion 42 a reaches the position of the second detector 42, the gripping position by the workpiece gripping device 1 is reached. If it is detected (see FIG. 9) and the support plate 22 passes the gripping position and the third detected portion 43a reaches the position of the third detector 43, the excessive displacement of the support plate 22 can be detected ( (Refer FIG.12 (c)).

  As shown in FIG. 2, the posture detection device 6 includes a support shaft 5 that is brought into contact with the workpiece W, a flexible member 5 a provided at the tip of the support shaft 5, and an exterior that allows the support shaft 5 to be retractable. The cylinder 61, the urging means 62 that urges the support shaft 5 in the direction in which the support shaft 5 is pressed against the work W, the contact detection means 63 that detects that the support shaft 5 is in contact with the work W, and the outer cylinder 61 are illustrated. 3 and an air cylinder 64 that moves in the vertical direction.

Here, the flexible member 5a may use, for example, rubber, foamed polystyrene, sponge, or the like to relieve the impact force when the support shaft 5 is brought into contact with the workpiece W and prevent damage to the workpiece W. it can.
The air cylinder 64 is a device for allowing the outer cylinder 61 and the support shaft 5 to escape upward so that the posture detection device 6 does not interfere with the workpiece W when the workpiece gripping device 1 is positioned. The support shaft 5 can come into contact with the workpiece W in a state where the shaft 5 is lowered downward.

  The contact detection means 63 comprises an optical sensor or the like, and moves by a predetermined movement amount s after the support shaft 5 contacts the workpiece W (see FIG. 9A), and the tip surface of the outer cylinder 61 and the support shaft When the support shaft 5 comes into contact with the workpiece W by the detected portion 63a that has moved to the facing position in a state where the front end surface of the surface 5 is flush (see FIG. 10A), a predetermined movement amount is obtained. Detects movement.

  The biasing means 62 is not particularly limited, and a coil spring or the like can be adopted. However, the elastic coefficient of the biasing means 62 is smaller than the elastic coefficient of the coil spring 31 of the elastic mechanism 3 (the elasticity of the elastic mechanism 3). The coefficient is set to be larger than the elastic coefficient of the biasing means 62).

  With this configuration, as shown in FIG. 9, the coil spring 31 (see FIG. 5) is bent during the movement amount s (see FIG. 9A) during which the support shaft 5 moves after contacting the workpiece W. The amount of movement s ′ (see FIG. 9B) is smaller.

The posture detection device 6 is supported by the bracket 124 and is disposed in the vicinity of the gripping mechanism 11 of the workpiece gripping device 1.
The posture detection device 6 can detect that the driven member 112 that grips the workpiece W is properly inserted into the gripped portion Wa of the workpiece W by the contact detection means 63.

  That is, when the tip 102 of the robot arm 101 (see FIG. 1) is brought close to the support shaft 5 in contact with the workpiece W and the tip 102 is moved further toward the workpiece W, together with the workpiece gripping device 1. The outer cylinder 61 moves downward in FIG. 3 so that the support shaft 5 is accommodated in the outer cylinder 61 against the urging force of the urging means 62, and the distal end surface of the outer cylinder 61 and the distal end surface of the support shaft 5 are surfaces. It comes into contact with the workpiece W together.

  At this time, the driven member 112 that grips the workpiece W is simultaneously inserted into the gripped portion Wa of the workpiece W at the tip portion (work gripping portion) of the gripping mechanism 11 with respect to the gripping mechanism 11. The attitude detection device 6 is disposed at an appropriate position and height.

  For this reason, the posture detection device 6 contacts the state where the front end surface of the outer cylinder 61 and the front end surface of the support shaft 5 are flush with each other by a predetermined amount of movement after the support shaft 5 contacts the workpiece W. By detecting by the detection means 63, it can be confirmed that the driven member 112 that grips the workpiece W is properly inserted into the gripped portion Wa of the workpiece W.

  As shown in FIG. 5, the positioning jig 400 of the gripping mechanism 11 includes a jig plate 401 in which a hole 401a, which is a gripped portion Wa (see FIG. 2) corresponding to various types of workpieces, is formed. And a guide post 402 erected on the jig plate 401.

  With this configuration, the guide member 221 disposed on the support plate 22 is fitted to the guide post 402 of the positioning jig 400, thereby positioning the workpiece gripping device 1 mounted on the distal end portion 102 of the robot arm 101. The jig 400 can be positioned.

  Then, in a state where the workpiece gripping device 1 is positioned on the alignment jig 400, the tip end portion (work gripping portion) of the gripping mechanism 11 is inserted into the hole 201a corresponding to a predetermined workpiece, and the movement restricting device 13 performs three axes. By restricting the movement of the moving mechanism 12, the gripping mechanism 11 can be locked in a positioned state.

Next, the operation of the posture control device 2 of the workpiece gripping device 1 according to the embodiment of the present invention will be described with reference to FIGS.
<Operation of elastic mechanism 3>
First, the operation of the elastic mechanism 3 will be described with reference mainly to FIGS. FIG. 6 to be referred to is a schematic front view showing the operation of the elastic mechanism 3 when the rigidity of the pallet on which the workpiece is placed is high, and (a) shows the tip portion (work gripping portion) of the gripping mechanism 11 to be gripped. (B) shows a state after the workpiece gripping portion is inserted into the gripped portion. FIG. 7 is a schematic front view showing the operation of the elastic mechanism 3 when the rigidity of the pallet on which the workpiece is placed is low.
In FIGS. 6 and 7, for convenience of explanation, the inclination of the workpiece W and the like are exaggerated, but in reality, the amount of deformation is very small.

  Here, the pallet 201 (see FIG. 1) may be in various forms depending on the purpose and application. For example, when the pallet 201 is made of a metal angle material or the like, the pallet 201 generally has high rigidity and is made of synthetic resin. Since the rigidity of the elastic mechanism 3 is low, the elastic mechanism 3 has different functions depending on the relationship between the urging force (elastic supporting force) of the elastic mechanism 3 and the rigidity of the pallet 201 as follows.

<When pallet rigidity is high>
When the rigidity of the pallet on which the workpiece is placed is high, the elastic mechanism 3 tends to operate so as to control the posture of the workpiece gripping device 1 in accordance with the posture of the workpiece W.
That is, as shown in FIG. 1, for example, when the elastic mechanism 3 tries to grip the workpiece W placed on the pallet 201 with the gripping mechanism 11, the workpiece W placed on the pallet 201 is moved to a predetermined position. When the workpiece is deviated or inclined, the posture of the workpiece gripping device 1 with respect to the workpiece W is controlled according to the amount of deviation due to this deviation or the like.

  Specifically, as shown in FIG. 6A, when the workpiece W has an inclination of an angle α, the robot arm 101 (see FIG. 1) moves the workpiece gripping device 1 to a predetermined position with respect to the workpiece W. When the tip end (work gripping portion) of the gripping mechanism 11 is inserted into the gripped portion Wa of the workpiece W, the support plate 22 is moved from the gripped portion Wa of the workpiece W according to the inclination angle α of the workpiece W. A moment M that attempts to rotate clockwise is applied reactively.

  Then, as shown in FIG. 6B, the moment M applied in this way absorbs the inclination of the angle α of the workpiece gripping device 1 with respect to the workpiece W flexibly as appropriate, and the support plate 22 according to the inclination angle α. By correcting the position and the inclination angle, the posture control device 2 can suitably control the posture of the workpiece gripping device 1 with respect to the workpiece W.

<When pallet rigidity is low>
When the rigidity of the pallet on which the workpiece is placed is low, the elastic mechanism 3 tends to operate so as to match the posture of the workpiece W with the workpiece gripping device 1.
That is, as shown in FIG. 1, for example, when the elastic mechanism 3 tries to grip the workpiece W placed on the pallet 201 with the gripping mechanism 11, the workpiece W placed on the pallet 201 is moved to a predetermined position. When the workpiece W is deviated or tilted, the misalignment or the like is corrected, and the workpiece W functions to match the posture of the workpiece gripping device 1.

  Specifically, as illustrated in FIG. 7A, when the distal end portion (work gripping portion) of the gripping mechanism 11 is inserted into the gripped portion Wa of the work W, the elastic mechanism 3 has its urging force (elastic support). Force) to apply a biasing force (pressing force) to the workpiece W placed on the pallet 201 (see FIG. 1) at an inclination angle α, so that the workpiece W is rotated counterclockwise by bending or deformation of the pallet 201. A moment M ′ to be rotated is applied.

  Then, as shown in FIG. 7B, the moment M ′ applied in this way acts so that the posture of the workpiece W becomes α ′ smaller than the inclination angle α. The posture of the workpiece W can be adjusted to the workpiece gripping device 1 by suitably correcting the deviation from the workpiece W.

  In this example, the case where the workpiece gripping device 1 functions so as to face the workpiece W in the direction of reducing the bending and deformation of the pallet has been described. However, the posture control device 2 greatly increases the bending and deformation of the pallet. The workpiece gripping device 1 may function so as to face the workpiece W in the direction in which the workpiece W is directed.

  In the present embodiment, for the sake of convenience, the case where the rigidity of the pallet 201 is high and the case where the rigidity is low has been described separately. However, in actuality, the pallet 201 is not strictly distinguished. However, it is possible to control the workpiece gripping device 1 so as to face the workpiece W suitably by appropriately adjusting the biasing force of the elastic mechanism 3.

<Operation of workpiece gripping device>
The operation of the workpiece gripping apparatus 1 will be described with reference to FIGS. 8 is a state before the workpiece is gripped by the gripping device, FIG. 9 is a state where the support shaft is in contact with the workpiece, FIG. 10 is a state where the outer cylinder of the support shaft is in contact with the workpiece, FIG. FIG. 5 is a partial front sectional view showing a state where clamping is completed.

  From the state in which the workpiece gripping device 1 does not contact the workpiece W (FIG. 8A), the tip 102 of the robot arm 101 is brought close to the support shaft 5 in contact with the workpiece W (FIG. 9A). When the tip portion 102 is further moved by s in a direction approaching the workpiece W, as shown in FIG. 10 (a), the outer cylinder 61 moves downward along with the workpiece gripping device 1 in FIG. The outer cylinder 61 is accommodated in the outer cylinder 61 against the urging force of the urging means 62, and the distal end surface of the outer cylinder 61 and the distal end surface of the support shaft 5 are flush with each other and abut against the workpiece W.

  Then, the contact detection means 63 detects a state in which the front end surface of the outer cylinder 61 and the front end surface of the support shaft 5 are flush with each other. In other words, the contact detection means 63 detects that the support shaft 5 has moved by a predetermined amount of movement after contacting the workpiece W by the detected portion 63a that has moved to the facing position.

  On the other hand, as shown in FIG. 10B, the displacement detection means 4 detects the presence of the second detected portion 42a that has moved to the position where the second detector 42 that detects the grip position by the workpiece gripping device 1 faces. Detect. In this way, the posture control device 2 confirms that the workpiece gripping device 1 has been positioned at the regular gripping position.

  At this time, if the workpiece gripping device 1 is positioned at the regular gripping position, the driven member 112 that grips the workpiece W at the tip (work gripping portion) of the gripping mechanism 11 at the same time has a predetermined gap δ (see FIG. 10 (a)) is formed and is properly inserted into the gripped portion Wa of the workpiece W.

  In this way, the attitude detection device 6 moves a predetermined amount after the support shaft 5 abuts against the workpiece W, and the state where the tip surface of the outer cylinder 61 and the tip surface of the support shaft 5 are flush with each other. By detecting by the contact detection means 63, it can be confirmed that the driven member 112 that grips the workpiece W is properly inserted into the gripped portion Wa of the workpiece W.

  Then, as shown in FIG. 11, the gripping mechanism 11 pushes the driving member 111 into the driven member 112 by the driving unit 114 in a state where the workpiece gripping device 1 is positioned in a predetermined posture with respect to the workpiece W. The workpiece W is moved (see FIG. 11A), and the workpiece W is gripped so as to press the driven member 112 of the gripped portion Wa of the workpiece W.

<Operation when the workpiece is excessively displaced>
The operation of the posture control device 2 of the workpiece gripping device 1 when the workpiece W placed on the pallet 201 in FIG. 1 is excessively displaced due to vibration or external factors will be described with reference to FIG.
The posture control device 2 detects the state by the posture detection device 6 and the displacement detection means 4 when the work W that cannot be posture-controlled by the elastic mechanism 3 is excessively displaced.

  When the workpiece W is excessively deviated from the predetermined placement state, as shown in FIG. 12A, when the tip of the gripping mechanism 11 tries to approach the gripped portion Wa of the workpiece W, the workpiece W Is excessively displaced, the tip of the gripping mechanism 11 cannot be inserted into the gripped portion Wa of the workpiece W, and the tip of the gripping mechanism 11 contacts the workpiece W.

  In the state where the tip of the gripping mechanism 11 is in contact with the workpiece W, the tip 102 of the robot arm 101 is moved so as to approach the support shaft 5 until it contacts the workpiece W, as shown in FIG. Thus, the support shaft 5 cannot be brought into contact with the workpiece W.

  For this reason, the contact detection means 63 cannot detect a state in which the support shaft 5 is moved by a predetermined movement amount s and the front end surface of the outer cylinder 61 and the front end surface of the support shaft 5 are flush with each other. .

  The support plate 22 is detected by the second detected portion 42a that has been moved to a position where the second detector 42 faces by the displacement detection means 4 without detecting that the support shaft 5 is in contact with the workpiece W. Is detected to have moved to the workpiece gripping position.

  However, even if the displacement detection means 4 detects that the support plate 22 has been displaced to the workpiece gripping position by the second detector 42, the contact detection means 63 indicates that the support shaft 5 is in contact with the workpiece W. Since it is not detected, it cannot be determined that the workpiece gripping device 1 has been positioned at a normal position with respect to the workpiece W.

  For this reason, when the distal end portion 102 of the robot arm 101 is further moved, the posture control device 2 has moved to a position where the third detector 43 faces by the displacement detection means 4 as shown in FIG. An excessive displacement of the support plate 22 is detected by the third detected portion 43a.

  In this way, the posture control device 2 detects the excessive displacement of the support plate 22 by the displacement detection unit 4 in a state where the contact detection unit 63 does not detect that the support shaft 5 is in contact with the workpiece W. Thus, it is determined that the workpiece W is excessively displaced, and an excessive load generated when the workpiece gripping device 1 tries to grip the workpiece W can be detected and avoided in advance.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications.
For example, in the above-described embodiment, the contact detection unit 63 detects that the support shaft 5 has moved by the movement amount s after contacting the workpiece W. However, the present invention is not limited to this. It is also possible to detect that the support shaft 5 is in contact with the workpiece W by providing a pressure sensitive means such as a piazo element at the tip of the workpiece. Further, a pressure sensing means may be provided at the tip of the support shaft 5 and a contact detection means 63 may be further provided.

  In the present embodiment, the posture detection devices 6 for detecting the posture of the workpiece gripping device 1 are disposed at three locations in the vicinity of the workpiece gripping device 1 corresponding to the workpiece gripping devices 1 disposed at three locations. However, the present invention is not limited to this, and the posture detection device 6 may not be disposed in the vicinity corresponding to the workpiece gripping device 1, and the number of workpiece gripping devices 1 and the posture detection devices 6 may not be the same. Alternatively, it may be arranged in different quantities at different locations.

1 Work gripping device (work work device)
DESCRIPTION OF SYMBOLS 2 Posture control apparatus 3 Elastic mechanism 4 Displacement detection means 5 Support shaft 5a Flexible member 6 Posture detection apparatus 11 Grasp mechanism 12 Triaxial movement mechanism 13 Movement control apparatus 21 Fixed plate 22 Support plate 31 Coil spring (spring member)
61 outer cylinder 62 biasing means 63 contact detection means 100 articulated robot 101 robot arm 111 driving member 111a wedge shaped part 112 driven member 112a gradient part 112b joint part 113 holder 113a main body part 113b tip part 114 driving means 400 alignment treatment Tool 401 Jig plate W Work Wa Grip part

Claims (7)

A posture control device for a workpiece gripping device that is mounted on a robot arm, engages with a workpiece supported by a workpiece support means, presses the workpiece, and grips a predetermined part of the workpiece,
A fixing plate for fixing to the robot arm;
A support plate provided with the workpiece gripping device;
An elastic mechanism that is mounted between the support plate and the fixed plate and elastically supports the support plate by urging the support plate away from the fixed plate;
An orientation detection device that detects the orientation of the workpiece gripping device with respect to the workpiece,
The posture detection device is
A support shaft that contacts the workpiece;
And a contact sensing means for the workpiece gripping device detects the proper position near Rukoto in a state where the support shaft is moved by a predetermined moving amount from the contact with the workpiece,
The elastic mechanism includes a displacement detection means for detecting a displacement of the support plate with respect to the fixed plate,
The displacement detection means includes a first detector that detects an original position of the support plate;
A second detector for detecting that the support plate is moved by a predetermined amount of movement from the original position detected by the first detector and the workpiece gripping device is in an appropriate gripping position;
A third detector for detecting excessive displacement of the support plate,
Wherein while pressing the workpiece by the workpiece holding device, the inclined posture of the workpiece holding device with respect to the workpiece by controlling the person the workpiece and the workpiece holding device so as to directly face by said elastic mechanism,
The contact sensing means and said displacement sensing means sensing result to the attitude control device of a work gripping device which is characterized that you detecting that the said workpiece and the workpiece holding device is directly facing based. The elastic mechanism, the attitude control device of a work gripping device according to claim 1 or claim 1, characterized in that is constituted by a spring member or a gas spring. The contact sensing means, the attitude control device of a work gripping device according to claim 1 or claim 2 characterized in that it comprises a pressure sensing means provided at the distal end of the support shaft. An outer cylinder for interior of the support shaft so as to be able to appear and retract;
An urging means for urging the support shaft in a direction of pressing the work shaft;
Further comprising a posture control device of a work gripping device according to claim 1, wherein any one of claims 3 to. The posture control apparatus for a workpiece gripping apparatus according to claim 4 , wherein an elastic coefficient of the elastic mechanism is larger than an elastic coefficient of the urging means. The posture control device for a workpiece gripping device according to any one of claims 1 to 5 , wherein a flexible member that comes into contact with the workpiece is provided at a tip of the support shaft. The workpiece support means is a pallet on which the workpiece is placed;
The posture control device for a workpiece gripping device according to any one of claims 1 to 6 , wherein:

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