CN103552849A

CN103552849A - Robot gripper for box body stacking and unstacking

Info

Publication number: CN103552849A
Application number: CN201310522904.6A
Authority: CN
Inventors: 贠超; 张进; 王伟; 王刚; 赵兴
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2013-10-29
Filing date: 2013-10-29
Publication date: 2014-02-05
Anticipated expiration: 2033-10-29
Also published as: CN103552849B

Abstract

A robot gripper for box body stacking and unstacking is applicable to logistics and warehousing industries of foods, medicine, tobaccos and the like, comprises a flange connected with a stacking robot, a top plate, a pair of downward inserting devices, a pair of side-pressing devices, a pair of bottom side-inserting devices, a selectable sucking disc and six groups of positioning sensor assemblies and has stacking and unstacking functions. By adopting the mode that box bodies are wholly surrounded, the possibility of box loosening in the quick carrying process is eliminated. The box body placing faces can be avoided during placing or gripping operation, a contact type placement is adopted, and impact caused falling, bumping and the like is avoided. The positioning sensor assemblies confirm poses of box bodies to be gripped according to a 'six-point positioning' principle, and accordingly confirmation of gripping poses of the gripper is achieved. Sensors in the different corresponding positioning sensor assemblies can be utilized to trigger interval time, and judgment on abnormal poses of the box bodies to be gripped can be performed and serves as a warning condition, so that timely shutdown and manual intervention and adjustment can be performed when the situation occurs.

Description

Robot paw for stacking and unstacking boxes

Technical Field

The invention relates to a robot paw for stacking and unstacking box-type packaged objects, which is suitable for logistics and storage industries in the fields of food, medicine, tobacco and petrochemical industry and is specially used for stacking and unstacking objects packaged by box bodies with orthogonal surfaces.

Background

In the industries such as logistics and storage in the fields of food, medicine, tobacco and petrochemical industry, the processes of stacking or unstacking are involved in the manufacturing of products, and the storage and transportation and circulation links of goods. At present, the stacking process adopts a stacking robot and a paw thereof to replace manual operation, but the stacking process is mostly realized by manual moving, for example, the stacking process of loading goods from a storage position is usually completed by a loader. Along with the market competition requirements of reducing the labor cost of products and improving the production automation degree, and because the palletizing robot and the paw are used for palletizing or unstacking, the palletizing robot has the advantage of being much higher than the manual operation efficiency, the robot and the paw are used for replacing manpower to complete palletizing and unstacking, and the robot paw is one of key components for realizing palletizing and unstacking.

The robot stacking operation process comprises the following steps: the stacking robot drives the paw to position and grab the object on the production line (such as a conveying belt), then the object is positioned and conveyed to the stacking position, then the object is placed, and after the object is placed, the paw is lifted up, and the next object stacking and conveying circulation link is entered; the robot unstacking operation process comprises the following steps: the stacking robot drives the paw to position and grab a certain object in the stack shape, then the object is positioned and conveyed to the placing position, and after the object is placed, the paw is lifted, and the next object is unstacked and conveyed in a circulating link. From the above-mentioned grabbing and carrying processes, the palletizing and unstacking have no essential difference in the gripper operation action, and the difference is the environmental condition of the grabbed object during grabbing or placing (e.g., whether adjacent boxes or other physical obstacles exist around the box to be grabbed). When the objects are piled, the objects are generally placed discretely and independently, no obstacle exists around the objects when the claws grab the objects, but when the objects are placed in a piled shape, the objects placed firstly bring interference or interference to the subsequent placing operation, and the interference or interference is one of the key problems to be solved by the piling operation. When unstacking is carried out, the grabbed articles are placed in a stack shape, unstacking operation needs to be carried out in sequence from the top layer to the bottom layer, the unstacking sequence of the articles on the same layer is also sequential, and physical interference exists between the adjacent articles and the to-be-grabbed articles when grabbing operation is carried out. In addition, when stacking or unstacking is carried out, the paw needs to position the object to be grabbed, a proper paw pose condition is created for further grabbing by the paw, particularly, the proper pose of the paw relative to the box body is determined for the object with a regular shape, such as the box body, and the key condition for smoothly grabbing the object by the paw is achieved.

Bagged material products are commonly stacked by adopting comb-tooth type mechanical claws, box-type products are also commonly stacked by adopting sucker-type claws, and grippers of a clamping plate type or a combination type of a sucker and a clamping plate are also adopted in documents. From the analysis of the structures and the working capacity of the claws of the types, firstly, the existing comb-tooth type claw has special requirements on the placing surface of an article to be grabbed, can only grab the article placed on a comb-tooth platform, and cannot be unstacked due to the limitation of the mechanical structure of the claw; secondly, although the placing surface of the object to be grabbed has no special requirement, the two operations of stacking and unstacking can be realized structurally, the surface smoothness of the object to be grabbed (such as a box-type packaging product) has special requirements, once the surface of the sucking position of the sucking disc has defects such as incompleteness or pits, the object cannot be reliably sucked, and the phenomena of bag falling/box falling are easily caused under the action of inertia force between the two operations after sucking and before placing due to the rapid carrying movement of the stacking robot, so that the carrying process is not reliable enough; thirdly, as for the existing gripper type or gripper type gripper combining the chuck type gripper, from the structural analysis, although the possibility of bag/box separation phenomenon during the transportation process is not generated, the structure of the gripper type gripper is easy to interfere with the surrounding environment (such as adjacent boxes of boxes to be grabbed in a stack shape or other obstacles) of the position where the articles are grabbed or placed, and therefore the gripper type gripper does not have the capability of unstacking. Still, the process of placing of article is mostly that splint release, and then makes article fall and place the target location, and this kind of process of placing is difficult to the requirement of meeting with to fragile class's needs article that need avoid assaulting to the accurate position and the gesture that article were placed can not fine obtaining the assurance, easily cause the bulk of buttress shape, crooked or even collapse the buttress. In addition, when box type packaging products are stacked or unstacked, the existing paw does not have the function of identifying the box body which is excessively inclined and is not suitable for being continuously grabbed (namely the box body with the abnormal posture), and the identification of the box body with the abnormal posture can ensure that the paw can avoid mistakenly grabbing the box body to be grabbed under the condition to cause the damage of the objects to be grabbed. The identification also protects the paw, and meanwhile, the identification function can provide an alarm condition so as to be convenient for stopping in time to perform manual intervention and adjustment.

In summary, the robot gripper is required to avoid obstacles around a box to be gripped and correctly determine the gripping pose of the gripper relative to the box, and the gripper has two functions of stacking and unstacking, so that the complicated operation of replacing different grippers is avoided when the two operation tasks of stacking and unstacking are required to be frequently changed. Moreover, the placing process of the paw is to be in contact type placing so as to avoid the impact on the grabbed box body in the placing process, and meanwhile, the bag/box dropping phenomenon can be avoided in the high-efficiency and rapid carrying process between grabbing and placing, so that the requirement of reliable carrying is met. In addition, the box body with the abnormal posture can be identified so as to improve the safety of stacking or unstacking operation.

According to one aspect of the present invention, there is provided a robot gripper for palletizing-unstacking of objects, characterized in that it comprises:

a suction cup for sucking an upper surface of an object;

a top plate serving as a mounting base for the other parts of the robot gripper;

the pair of lower inserting devices are respectively provided with a lower inserting plate and are used for being inserted into two adjacent side surfaces of the object and/or two gaps between the object and the adjacent object in the stack along the tangential direction downwards to create a clamping condition for completing the grabbing of the object;

a pair of side plate devices which are respectively connected with the top plate in an installing way and respectively face the installing positions of the pair of lower inserting devices;

a pair of lateral compression devices, which are respectively fixedly arranged on the pair of side plate devices and respectively comprise an extensible compression plate, wherein the working surface of the compression plate is opposite to the working surface of the corresponding lower inserting plate inserted in place downwards, and the lateral compression devices are used for jointly clamping two side surfaces of an object, which are opposite to each other;

and the pair of bottom side inserting devices are respectively provided with a side inserting plate and are respectively fixedly arranged on the telescopic lower side plates on the pair of side plate devices for avoiding the object from being placed to generate interference to the side inserting devices, so that the interference is avoided, and the side inserting plates of the bottom side inserting devices cannot be inserted into the bottoms of the objects.

Disclosure of Invention

The invention aims to provide a robot gripper with two functions of stacking and unstacking aiming at hexahedral box type packaging products with orthogonal surfaces, which can smoothly pick up a box body under the condition that a placing surface (such as the upper surface of the box body under the box body to be picked in a stack shape, or the working surface of a stack-shaped tray, or the surface of a conveyor belt) of the box body is a plane, does not produce a box falling phenomenon in the processes of picking up, carrying and placing, and is placed in a contact mode, so that no impact is caused on the products, and the compact and tidy stack shape is ensured. Particularly, when unstacking operation is carried out, the mechanical claw can smoothly grab the box body to be grabbed in the stack shape, and can not change the position and the posture of other box bodies, namely, the situation of mechanical interference with the unstacking environment can be avoided or avoided. In addition, the mechanical claw has the function of identifying the abnormal pose box body, and can provide an alarm condition.

The principle of the composition structure of the invention is as follows: the flange plate is used for being connected with the wrist at the tail end of the small arm of the stacking robot in an installing mode; the square paw top plate is a mounting and connecting foundation for the flange plate and other devices of the paw; the pair of lower inserting devices are respectively arranged at the edge central positions of two adjacent edges of any one corner of the upper surface of the square top plate; the side plate devices are divided into an upper side plate and a lower side plate, the upper side plate is fixedly connected with the top plate through bolts, the mounting positions of the side plate devices can be adjusted in a telescopic mode along the normal direction of the surface of the upper side plate so as to adapt to the sizes of different grabbed boxes, the lower side plate can slide up and down relative to the fixed upper side plate through the guide rod, and the guide rod is provided with a spring for realizing that the lower side plate generates a reset action after the contact thrust of the grabbed boxes facing the lower side plate is removed; the working surfaces of the respective pressing plates of the pair of lateral pressing devices are opposite to the working surfaces of the lower inserting plates of the two lower inserting devices, so that four side surfaces of the box body to be grabbed can be clamped and tightly held; the side inserting devices are arranged on the bottom side of the lower side plate, and in a state that the side inserting plates are retracted, the side inserting devices on the bottom side are arranged to avoid mechanical interference with a placing surface of the box body and slide upwards under the action of contact thrust of the placing surface, so that the placing surface of the box body is avoided, the avoiding distance can be adjusted according to the height of the box body by a guide positioning sleeve on a guide rod of the side plate device, when the box body is grabbed and lifted, the lower side plate and the side inserting devices on the bottom side generate resetting action, when the resetting is completed, the working surface of the side inserting plate just stays at a slightly lower position of the grabbed and lifted bottom surface of the box body, and at the moment, the side inserting plate can be inserted into the bottom of the box body; the suckers are arranged on the lower surface of the top plate, one or more suckers or no suckers can be arranged according to needs, and the suckers, the lower inserting device and the lateral pressing device can jointly grab the box body; the arrangement mode utilizes the six-point positioning principle of determining the pose of a space object to detect and judge the pose of a box body to be grabbed, and accordingly the pose of a paw is adjusted to ensure that a lower inserting plate of a lower inserting device of the paw is accurately and tangentially inserted into two adjacent side surfaces of the box body to be grabbed or a gap between the lower inserting plate and the adjacent box body in a stack shape. The time interval between the corresponding sensors of the six groups of positioning sensor components is triggered can be used as a condition for judging the abnormal pose box body.

The invention has the following functional and structural characteristics:

firstly, have pile up neatly and pile up neatly two kinds of functions. This feature avoids the need to change the gripper between two different operations, stacking and unstacking.

And secondly, grabbing the box body in a fully-surrounding manner. The lower inserting plate working surfaces of the two lower inserting devices, the pressing plate working surfaces of the two lateral pressing devices and the side inserting plate working surfaces of the two bottom lateral inserting devices are used for carrying out full-surrounding type grabbing on a grabbed box body together with the optionally arranged suckers, and the structure eliminates the possibility of box falling in the process of rapid carrying.

Thirdly, under the condition of achieving the purpose, the mechanical structure of the paw can eliminate or avoid the environmental interference which prevents the grabbing action from being realized in the grabbing process. The lower inserting device is vertically arranged on the top plate, and the mechanical structure of the lower inserting device is arranged on the top surface of the box body except the overlapped part of the lower inserting plate and the box body when the lower inserting plate is downwards inserted into two adjacent side surfaces of the box body in a tangential way, so that the part of the structure of the paw can not interfere with the adjacent box body to be grabbed or placed in the stack shape when grabbing or placing operation is carried out; the lateral hold-down device and the bottom lateral insertion device are mounted in positions facing the lower insertion device and are arranged on two other adjacent side surfaces of the box body, and generally, the two side surfaces in the stack shape are not adjacent to the box body in the facing direction, so that interference is avoided. The lower side plate slides up and down relative to the upper side plate to realize the avoidance of the paw to the box body placing surface.

Fourthly, the side flashboards are inserted into the box body without obstacles and are placed in a contact mode. When the box body is grabbed, in order to realize that the side inserting plate of the side inserting device at the bottom extends out and is tangentially inserted into the bottom surface of the box body, but can not be mistakenly inserted into the box body, a mechanism with a lower side plate capable of sliding and stretching is adopted. When the lower side plate is downwards reset with the side inserting device arranged on the lower side plate, the side inserting plate can just stay at a lower position of the bottom surface of the box body, and conditions are created for the side inserting plate to be inserted into the bottom of the box body without obstacles. Besides the avoidance of the side inserting devices at the lower side plate and the bottom side to the box body placing surface, the mechanism also creates conditions for placing the grabbed box body in a contact manner. When placing the box, the hand claw is held the box and is held the operation of placing, when closing on place the face and lower side board and bottom side cartridge put not produce the contact with placing the face, two side plugboards retract simultaneously, the hand claw continues to transfer, lower side board and bottom side cartridge put along with place the face and take place the contact and then produce thrust bottom, under this contact thrust effect, lower side board is put with bottom side cartridge and is slided upwards, dodge the box and place the face action, put in place until the bottom half with place the face coincidence, the hand claw is transferred and is stopped, then, make the side direction pressure strip retract simultaneously, the lower plugboard retracts upwards, the sucking disc release, the hand claw upwards lifts up, to this point, accomplish the non-impact contact and place the box action.

Fifthly, the posture of the box body to be grabbed is determined by utilizing six groups of positioning sensor assemblies, and the grabbing pose of the front paw is adjusted and determined according to the posture, so that the accuracy of the inserting position of the lower inserting plate is ensured.

Sixthly, the box body with the abnormal posture which is not suitable for grabbing is distinguished. When the posture of the box body to be grabbed in the stack shape is too inclined, for example, the upper surface of the box body to be grabbed is excessively inclined, when the sensors in the three groups of sensor components arranged on the top plate downwards approach the box body to be grabbed by the claws, the sensors cannot be triggered simultaneously, the time period from the moment when the sensor is triggered firstly to the moment when the last sensor in the three groups of sensor components is triggered is used as a criterion, the inclination degree of the upper surface of the box body is judged, and the longer the interval time is, the more the top surface of the box body is inclined. When the box body is too inclined and is not suitable for continuous grabbing, the paw and the palletizing robot stop all actions, and manual intervention and adjustment are further carried out, so that the intelligent robot palletizing system also has an intelligent distinguishing function to a certain degree.

Drawings

FIG. 1 is a schematic perspective view of a palletizing-unstacking robot gripper according to one embodiment of the present invention.

FIG. 2 is a schematic diagram of the arrangement of suction cups in a palletising-unstacking robot paw in accordance with an embodiment of the invention.

Fig. 3 is a schematic view of a downstacker according to one embodiment of the present invention.

Fig. 4 is a schematic view of a side panel arrangement according to an embodiment of the present invention.

Figure 5 is a schematic view of a lateral compression device according to one embodiment of the present invention.

Fig. 6 is a schematic view of a bottom side cartridge device according to an embodiment of the present invention.

FIG. 7 is a schematic view of a positioning sensor assembly according to one embodiment of the present invention.

Detailed Description

Embodiments of the gripper for a carton palletizing-unstacking robot according to the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 and 2, a palletizing-unstacking robot gripper according to an embodiment of the present invention comprises: the flange plate 1, the top plate 2, a pair of

lower insertion devices

3 and 4, a pair of

side plate devices

5 and 6, a pair of lateral

pressing devices

7 and 8, a pair of bottom

side insertion devices

9 and 10, position sensor assemblies 11 to 16 respectively arranged on the top plate and the side plates, a sucker mounting frame 17 arranged below the top plate and a sucker 18.

The flange plate 1 is a mechanical interface for installing and connecting the claw of the stacking-unstacking robot and the wrist of the stacking robot, and is provided with a spigot 102 and a bolt hole 101. The top plate 2 is generally square and is the mounting base for the paw and other devices, and is provided with a long hole 201 for adjusting and mounting the side plate device.

Fig. 3 shows a lower cartridge device 3 according to an embodiment of the invention; the lower cartridge 4 is identical in construction to the lower cartridge 3. The two

lower insertion devices

3 and 4 are vertically mounted to two adjacent sides of, for example, any one of the corners of the upper surface of the square roof panel 2 through mounting brackets 303 (see fig. 1).

The

downstream devices

3 and 4 each comprise the following components: a cylinder 310 mounted to the frame 303 by

cylinder mounting brackets

302, 304; a lower insert plate 305 mounted to the lower ends of the piston rod 306 and the

guide rods

301 and 314 of the cylinder 310 by nuts (not shown); two linear bearing blocks 307, 312 supporting the

guide rods

301, 314; two groups of

linear bearings

308, 313 in pairs;

position sensors

309, 311 mounted on the cylinder 310.

The function of the

lower insertion devices

3 and 4 is that their lower insertion plates 305 are inserted tangentially downwards into two adjacent sides of the object to be gripped (e.g. a box) or into two gaps between the object (e.g. a box) and the adjoining object (e.g. a box) in the form of a stack, creating a clamping condition for further completion of the gripping of the object. The force between the objects in the pile at the gap is small and the gap is present objectively, the insertion can be carried out smoothly, as follows: the lower inserting plates 305 of the lower inserting

devices

3 and 4 are driven by the air cylinder 310 to be inserted into the gaps at two sides of the object in a downward tangential manner, wherein the insertion depth is about one third of the height of the object (such as a box); according to an embodiment of the present invention, the insertion depth depends on the length of the lower insert plate 305 and the mounting positions of the two

position sensors

309 and 311 mounted on the cylinder 310.

Fig. 4 shows a side panel arrangement 5 according to an embodiment of the invention; the side plate device 6 has the same structure as the side plate device 5 except that the number of the installation groups of the positioning sensor components is different. The

lateral plate devices

5 and 6 are the mounting bases for the lateral hold-down

devices

7 and 8, the bottom lateral plug-in

devices

9 and 10 and the corresponding positioning sensor assemblies 14-16 (see fig. 1).

The

side plate devices

5 and 6 are connected with the top plate 2 through bolts (not shown) and respectively face the installation positions of the

lower insertion devices

3 and 4; the mounting positions of the

side plate units

5 and 6 can be adjusted along the normal direction of the respective upper side plates 501 to adapt to boxes with different sizes (see fig. 1). Taking the side plate device 5 as an example, the lower side plate 515 can slide relative to the upper side plate 501 fixed on the top plate 2 along the axial direction of the guide rods 505 and 523, and the sliding distance can be adjusted by different installation positions of the guide rod positioning sleeves 502 and 526 on the guide rods 505 and 523; a plurality of guide positioning sleeve mounting holes 528 are preset on the upper half parts of the guide rods 505 and 523 in a manner that hole axes are crossed, and the guide positioning sleeves 502 and 526 are matched and connected with the guide rods 505 and 523 through a bolt and a nut 527 for reaming holes and are fixed. The lower side plate 515 is fixed to the guide rods 505 and 523 by the

guide rod holders

509, 511, 516, and 518 and the

cylindrical pins

510, 512, 517, and 519. The linear bearing blocks 503, 507, 521, and 525 are fixedly attached to the upper side plate 501, and the four linear bearings 504, 506, 522, and 524 attached to the four linear bearing blocks 503, 507, 521, and 525 form linear sliding pairs corresponding to the guide rods 505 and 523.

A

spring

508, 520 is mounted between the guide rod housing 509 and 518 and the linear bearing housing 507 and 521, respectively, in the direction of the respective guide rod axis. The

springs

508, 520 hold the upper and

lower side plates

501 and 515 in a state of being separated from each other, that is, a state of returning the lower side plate 515 downward, without the lower side plate 515 being urged by upward contact with the mounting surface of the case (object). Two protective caps 513 and 514 made of rubber or resin are mounted on the lower side plate 515 for preventing the case body placing surface from being scratched or scratched by a paw when the lowest edge of the lower side plate is in contact with the case body placing surface during the grabbing or placing operation.

Fig. 5 shows the configuration of the lateral pressing device 7 according to one embodiment of the present invention; the lateral pressing device 8 is identical in construction and structure to the lateral pressing device 7. The two lateral compression means 7 and 8 are fixedly mounted on the upper side plate 501 of the side plate means 3 and 4, respectively, by means of brackets, as indicated by reference number 701 in fig. 5 (see fig. 4). The lateral compression device 7 comprises: an air cylinder 709 mounted to the frame 701 by air

cylinder mounting brackets

702 and 712; a pressing plate 705 mounted to the front ends of the piston rod 707 and the

guide rods

713 and 714 via nuts (not shown), and having grooves 704 for increasing friction on its end surface; two linear bearing blocks 703 and 715; two groups of linear bearings, which are two by two and are indicated by

reference numerals

706 and 711, are respectively arranged on the

linear bearing seats

703 and 715; two

position sensors

708, 710 for determining the extension of the pressure strip 705.

The faces (not shown) of the pressure plates 705 which project from the lateral pressure means 7 face the faces (not shown) of the lower insert plate into which the lower insert device 4 is inserted downwards, jointly clamping the two sides of the respective box facing away from each other. Likewise, the holding-down plates of the other group of lateral holding-down devices 8 and the lower insert plate of the lower insert device 3 clamp the other group of opposite sides of the box, so that the box (object) to be gripped is gripped when the gripper is lifted upwards.

Fig. 6 shows a bottom side cartridge device 9 according to an embodiment of the invention; the bottom cartridge 10 is identical in construction to the bottom cartridge 9. The two bottom

lower insertion devices

9 and 10 are fixedly mounted on the lower side plates of the side plate devices 5 and 6 (see fig. 1) by means of brackets as indicated by reference numeral 902 in fig. 6, respectively, and can slide up and down together with the lower side plates. The purpose of this sliding is to avoid interference of the resting surface of the box (object) to be gripped against the mechanical structure of the downward-insertion device, which could prevent the side insertion plate of the bottom side insertion device from being inserted into the bottom of the box.

The bottom

lateral insertion device

9 or 10 comprises: a bracket 902 for mounting the bottom side insertion device on the lower side plate 515, an air cylinder 909, a pair of air

cylinder mounting brackets

901 and 905, a pair of

guide rods

903 and 904, a pair of linear bearing

seats

907 and 912, two sets of

linear bearings

906 and 911 in pairs, a pair of

position sensors

908 and 910, and a side insertion plate 914 are mounted on the front ends of the piston rod 913 and the

guide rods

903 and 904 through nuts (not shown).

FIG. 7 illustrates a position sensor assembly 11 according to one embodiment of the present invention; the structure and the triggering operation principle of the

positioning sensor assemblies

12, 13, 14, 15 and 16 are completely the same as those of the positioning sensor assembly 11. The position sensor assembly 11 includes a sensor 1110, a sensor mounting bracket 1109, a sliding trolley 1101, an armature 1102, an adjustment nut 1103,

linear bearings

1104, 1105, a spring 1108, an adjustment nut 1106, and a contact 1107. The

position sensor assemblies

11, 12, 13 are mounted on the top plate 2 such that the geometric center of each contact 1107 is in a plane that is parallel to the plane of the top plate; the

positioning sensor assemblies

14, 15 are mounted on the upper side plate of the side plate arrangement 6 with their geometric centre connecting lines of the two contacts 1107 parallel to the respective upper plate plane; the position sensor assembly 16 is mounted on the upper side plate 501 of the side plate arrangement 5. Taking the positioning sensor assembly 11 as an example, when the surface of the box to be grabbed is in moving contact with the contact 1107 in the normal direction, under the action of the contact force, the sliding contact rod 1101 retracts, so as to drive the contact block 1102 to move, so that the sensor pulley 1111 slides on the surface of the box, and after a certain position is reached, the sensor 1110 is triggered.

The spatial positions of the six contacts 1107 of the six positioning sensor assemblies 11 to 16 are utilized to determine the placing posture of the box to be grabbed before being grabbed, and the six-point positioning principle of determining the spatial position of the object is applied. After the posture of the box body to be grabbed is determined, the inserting position positioning of the two lower plug-in lower inserting plates is completed.

The process of determining the placing posture of the grabbing box body before being grabbed by the six groups of positioning sensor assemblies 11-16 is as follows:

firstly, after the gripper is driven by the stacking manipulator to complete the basic positioning of the box to be grabbed, without pause, the gripper continues to approach downwards from above the box to be grabbed, ideally, the three sensors 1110 in the

sensor assemblies

11, 12 and 13 mounted on the top plate 2 are simultaneously triggered, the downward approach movement of the gripper is stopped, and the positioning of the upper surface of the box to be grabbed is completed; if the three sensors 1110 are triggered successively, after all the triggering is finished, the downward approaching movement of the paw is stopped, and the positioning of the upper surface of the box body to be grabbed is finished.

Secondly, during the positioning of the upper surface of the box to be gripped, the gripper also approaches the side of the box opposite the two

lateral plate devices

5 and 6, during which the gripper is driven by the rotation of the robot wrist to adjust in rotation around the corresponding vertical axis, and at the moment when the triggering of the corresponding sensor 1110 is completed, the attitude positioning is completed.

Taking the unstacking operation as an example, the grabbing action comprises the following steps: the paw is driven by a small arm of the palletizing robot to approach the placing position of the box body to be grabbed (or other objects) downwards from the upper part of the box body to be grabbed; determining the posture of the box to be grabbed through the positioning sensor assemblies 11-16 (see fig. 1), wherein the contact 1107 of the three positioning sensor assemblies 11, 12 and 13 on the top plate 2 of the paw is in contact with the upper surface of the box, and the slide bar 1101 in the positioning sensor assemblies is pushed to retract upwards until the downward movement of the paw stops after the sensors 1110 in all the sensor assemblies arranged on the top plate 2 are triggered; in the process, the two side plate devices 5 and 6 of the paw approach to the corresponding side surface of the box body to be grabbed, after the sensor 1110 in the corresponding positioning sensor assembly is completely triggered, the lateral approaching positioning is completed, and thus, the lower inserting plates 305 of the lower inserting devices 3 and 4 are just positioned right above the gap between the box bodies; when the paw approaches the box to be grabbed downwards, the lower side plates 515 of the side plate devices 5 and 6 are contacted with the placing surface of the box through the lower edges of the protective caps 514 to generate contact thrust, so that the lower side plates 515 with the side insertion devices 5 and 6 are retracted upwards in a sliding manner, and the set requirement of the retraction distance is met (the sliding retraction distance is adjusted according to the height of the box and the working surface (not marked) of the reset rear side insertion plate 914 is slightly lower than the bottom surface of the box to be grabbed and is positioned on the plane) (at the moment, the moment when the sensors 1110 in all the sensor assemblies 11-13 on the top plate 2 are triggered), the lower insertion plates 305 are inserted downwards to be in place, the pressing plates 704 of the lateral pressing devices 7 and 8 are extended forwards to press corresponding side surfaces, the box is clamped together with the lower insertion plates 305 after the pressing to be in place, the suckers 18 act to suck the upper surface of the box (object), then the paw drives the grabbed box to be grabbed to be lifted When the reset is completed, the working surface (not shown) of the side inserting plates 914 of the side inserting devices 9 and 10 is just slightly lower than the bottom surface of the box body, so that the side inserting plates 914 are smoothly inserted into the bottom surface of the box body to support the box body, and the grabbing process is completed.

Claims

1. A robot gripper for palletization-unstacking of objects, characterized in that it comprises:

a suction cup (18) for sucking an upper surface of the object;

a top plate (2) serving as a mounting base for the other parts of the robot gripper;

a pair of lower insertion devices (3, 4) which are respectively provided with a lower insertion plate and are used for inserting the lower insertion plates downwards into two adjacent side surfaces of the object and/or two gaps between the object and the adjacent object in the stack along the tangential direction, thereby creating a clamping condition for completing the grabbing of the object;

a pair of side plate devices (5, 6) which are respectively connected with the top plate (2) and respectively face the installation positions of the pair of lower insertion devices (3, 4);

a pair of lateral compression means (7, 8) each fixedly mounted on one of said pair of side plate means (5, 6) and each comprising an extendable compression plate (705), the working surface of said compression plate (705) facing the working surface of the lower insert plate of the corresponding lower insert device (3, 4) inserted in position downwards for jointly clamping two sides of the object facing away from each other;

a pair of bottom side-mounted units (9, 10) each having a side-mounted board (914) and each fixedly mounted to the pair of side-mounted units (5, 6) above the telescoping lower side-plate (515) for preventing the object from being placed in facing relation to the side-mounted units (9, 10) so as to prevent interference with the side-mounted units (914) from being inserted into the bottom of the object.

2. The robotic gripper of claim 1, further comprising:

the flange plate (1) is a connecting interface of the robot paw and a wrist part on a small arm of the stacking robot;

first to sixth positioning sensor assemblies (11-16) for determining a placement posture of the object before the object is grabbed.

3. A robot gripper according to claim 1 or 2, characterized in that:

the pair of lower insertion devices (3, 4) are identical in structure to each other, and each of the lower insertion devices (3 or 4) includes:

a first cylinder (310) mounted on a first bracket (303) and comprising a first piston rod (306);

two first guide rods (301, 314);

two first linear bearing seats (307, 312) supporting the two first guide bars (301, 314) together;

two groups of two first linear bearings (308, 313) which are arranged on the two first linear bearing seats (307, 312) in a pairwise manner and are used for guiding and supporting the two first guide rods (301, 314);

the lower insert plate (305) is fixedly arranged at the lower end of the first piston rod (306) and the lower ends of the two first guide rods (301 and 314);

position sensors (309, 311) mounted on the first cylinder (310);

wherein, the lower inserting plates (305) of the lower inserting devices (3, 4) are downwards inserted into two adjacent side surfaces of the object to be grabbed and/or two gaps between the target object and the adjacent object in the stack shape along the tangential direction, so as to create a clamping condition for further completing the grabbing of the object;

the actions of the lower plug board (305) comprise: the lower inserting plate (305) is driven by the first air cylinder (310) to be inserted downwards tangentially into the gaps on the two sides of the object.

4. The robotic gripper of claim 3, wherein:

the insertion depth of the lower insert plate (305) into the gaps at both sides of the object tangentially depends on the length of the lower insert plate (305) and the installation positions of the two position sensors (309, 311) installed above the first cylinder (310),

the top plate (2) is a square top plate and

the pair of lower insertion devices (3, 4) are vertically arranged at the central positions of two adjacent edges of any corner of the upper surface of the top plate (2) through first supports (303).

5. A robot gripper according to claim 1 or 2, characterized in that:

the structures of the pair of side plate devices (5, 6) are the same with each other,

the pair of side plate devices (5, 6) are connected with the top plate (2) and respectively face the installation positions of the pair of lower insertion devices (3, 4);

the mounting positions of the pair of side plate devices (5 and 6) can be adjusted along the normal direction of the plate surface of the respective upper side plate (501) to adapt to objects with different sizes;

each of the pair of side plate devices includes:

a pair of second guide rods (505, 523);

an upper side plate 501 fixed on the top plate 2;

a pair of guide rod positioning sleeves (502, 526) for positioning on the pair of second guide rods (505, 523), respectively;

a lower side plate (515) which can slide along the axial direction of the second guide rod (505, 523) relative to the upper side plate (501), wherein the sliding distance can be adjusted by different installation positions of the guide rod positioning sleeves (502, 526) on the second guide rod (505, 523);

guide rod seats (509, 511, 516, 518) and cylindrical pins (510, 512, 517, 519) for fixedly mounting the lower side plate (515) on second guide rods (505, 523);

second linear bearing seats (503, 507, 521, 525) fixedly mounted on the upper side plate (501);

second linear bearings (504, 506, 522, 524) mounted on the second linear bearing seats (503, 507, 521, 525), respectively, and constituting a linear sliding pair corresponding to the second guide rods (505, 523);

first springs (508, 520) respectively mounted in the direction of the axis of the corresponding guide rod between the guide rod seats (509, 518) and the corresponding second linear bearing seats (507, 521),

wherein the first spring (508, 520) keeps the upper and lower side plates (501, 515) in a state of being separated from each other, that is, a state of returning the lower side plate (515) downward, without the lower side plate (515) being urged upward by contact with a mounting surface of an object.

6. The robotic gripper of claim 5, wherein:

a plurality of guide positioning sleeve mounting holes (528) are preset in the upper half parts of the second guide rods (505 and 523) in a manner that hole axes are staggered in a cross mode, and the guide positioning sleeves (502 and 526) are matched, connected and fixed with the second guide rods (505 and 523) through a hinged hole by bolts and nuts (527);

two protective caps (513, 514) are mounted on the lower side plate (515) for preventing the placing surface of the object from being scratched or scratched by the paw when the lowest edge of the lower side plate is in contact with the placing surface during the grabbing or placing operation.

7. The robot gripper according to claim 1 or 2, characterized in that said pair of lateral pressing means (7, 8) are of the same configuration as each other and respectively comprise:

a pair of second cylinder mounting brackets (702 and 712);

a second support (701);

a pair of third guide bars (713, 714);

a second cylinder (709) mounted on the second bracket (701) through second cylinder mounting brackets (702 and 712), having a second piston rod (707);

a pressing plate (705) mounted on the front ends of the second piston rod (707) and the third guide rods (713, 714), and grooves (704) for increasing friction are formed on the end surface of the pressing plate;

two third linear bearing blocks (703 and 715);

two groups of third linear bearings (706, 711) which are pairwise arranged are respectively arranged on the third linear bearing seats (703, 715);

a position sensor (708, 710) for determining a protrusion distance of the compacting plate (705);

wherein,

the working surfaces of the pressing plates (705) extending out of the lateral pressing devices (7, 8) face the corresponding working surfaces of the lower inserting plates inserted into positions downwards by the lower inserting devices (4, 5), and the working surfaces clamp two side surfaces of the corresponding object back to each other together, so that when the robot claw is lifted upwards, the object to be grabbed is grabbed.

8. A robot gripper according to claim 1 or 2, characterized in that

The pair of bottom side insertion devices (9, 10) are identical in structure to each other and comprise:

a pair of third cylinder mounting brackets 901 and 905;

a third bracket 902;

a pair of fourth guide rods 903 and 904;

each is fixedly arranged on the lower side plate of the corresponding side plate device (5, 6) through a corresponding third bracket (902) and can slide up and down along with the lower side plate,

the sliding is used for and can avoid the interference of the placing surface of the object to be grabbed to the mechanical structure of the downward inserting device.

9. The robot gripper according to claim 2, characterized in that the first to sixth positioning sensor assemblies (11-16) are structurally identical to each other and each comprise:

a sensor mounting bracket (1109);

sensors (1110) mounted on the sensor mounting brackets (1109), respectively;

a sliding feeler lever 1101;

a contact block 1102;

an adjusting nut 1103;

a pair of fourth linear bearings (1104, 1105);

a second spring (1108);

an adjusting nut 1106;

a contact (1107),

sensor pulley (1111)

Wherein

The first to third positioning sensor assemblies (11, 12, 13) are mounted on the top plate (2) by adjusting the nut 1103 so that the geometric center of the contact tip (1107) of each is in the same plane, which is parallel to the plane of the top plate (2);

the fourth and fifth position sensor assemblies (14, 15) are mounted on the upper side plate of one of the side plate arrangements (6) with the line of the geometric centres of their contacts (1107) parallel to the respective upper plate plane by adjusting the nut 1103;

a sixth positioning sensor assembly (16) is mounted on the upper side plate (501) of the other side plate device (5), and the protrusion distance of a contact 1107 of the sixth positioning sensor assembly is adjusted by an adjusting nut 1103;

when the surface of an object to be grabbed is in moving contact with the contact head (1107) in the normal direction, the sliding contact rod (1101) retracts under the action of contact force, so that the contact block (1102) is driven to move, the sensor pulley (1111) slides along the surface of the contact block (1102) in tangential contact with the sensor pulley, and the corresponding sensor (1110) is triggered after the sliding reaches a certain distance;

the spatial positions of six contacts (1107) of the first to sixth positioning sensor assemblies (11-16) are utilized, the placing posture of the object to be grabbed before being grabbed is determined by using the 'six-point positioning' principle of determining the spatial position of the object, and the inserting position positioning of the lower inserting plates of the two lower inserting devices is completed by determining the posture of the object to be grabbed.

10. Method for determining the placing posture of a gripped object before gripping with a robot gripper according to claim 9 in palletization-unstacking of objects, characterized in that it comprises:

A) after the paw is driven by the stacking manipulator to complete the basic positioning of the object to be grabbed, the paw continues to approach downwards from the upper part of the object to be grabbed under the condition of no pause,

B) stopping the downward approach movement of the gripper when all the sensors (1110) of the first to third sensor assemblies (11, 12, 13) are activated, thereby completing the positioning of the upper surface of the object to be gripped;

C) and when the upper surface of the object to be grabbed is positioned, the two side plate devices (5 and 6) of the paw approach to the opposite object side surfaces, in the approaching process, the paw is driven to rotate around a corresponding vertical shaft through the rotation of a flange plate (1) of the palletizing robot so as to perform corresponding adjustment, and when the corresponding sensors 1110 of the fourth to sixth sensor assemblies (14, 15 and 16) are all triggered, the posture positioning is completed.

11. Method of performing unstacking operations of palletization of objects with a robotic gripper according to claim 9, characterized in that it comprises:

J) driven by a small arm of the stacking robot, the paw approaches the placing position of the object to be grabbed downwards from the upper part of the object to be unstacked;

K) determining the posture of an object to be grabbed through the first to sixth positioning sensor assemblies (11-16), wherein a contact 1107 in the three positioning sensor assemblies (11, 12 and 13) on the top plate (2) is in contact with the upper surface of the object, pushing a sliding rod 1101 in the positioning sensor assemblies (11, 12 and 13) to retract upwards, and stopping the downward movement of the paw until the sensors (1110) in the first to third positioning sensor assemblies arranged on the top plate (2) are triggered;

l) simultaneously with the step K), enabling the two side plate devices (5 and 6) of the paw to approach to the corresponding side surfaces of the corresponding objects to be grabbed, and completing lateral approach positioning when the sensors (1110) in the fourth to sixth positioning sensor assemblies are all triggered, wherein the lower insertion plates (305) of the pair of lower insertion devices (3 and 4) are just positioned right above the gaps between the objects;

m) when the paw is approaching downwards to the object to be grabbed, the lower side plates (515) of the pair of side plate devices (5 and 6) are contacted with the object placing surface to generate contact thrust, so that the lower side plates (515) carry the pair of side inserting devices (5 and 6) to slide upwards and retract, the set requirement of retraction distance is met, namely when all the sensors (1110) in the first to third sensor assemblies (11-13) are triggered, the lower inserting plate (305) is inserted downwards to be in place, the pressing plates (704) of the pair of lateral pressing devices (7 and 8) extend forwards to press the corresponding side surfaces of the object and clamp the object together with the lower inserting plate (305) after the pressing plates are in place,

n) sucking the upper surface of the object with a suction cup (18);

o) the grabbed object is driven to lift by the gripper, the lower side plate on the side plate device is reset under the combined action of gravity and spring restoring elasticity along with the side insertion device at the bottom,

p) when the resetting is completed, the working surface of the side inserting plate (914) of the side inserting devices (9 and 10) is just lower than the bottom surface of the object, so that the side inserting plate (914) is inserted into the bottom surface of the object to support the object, and the grabbing process is completed.