WO2003022034A1

WO2003022034A1 - Pick and place robot

Info

Publication number: WO2003022034A1
Application number: PCT/DK2002/000580
Authority: WO
Inventors: Kristian Madsen; Morten Kahr Nielsen
Original assignee: Gartneriet Pkm Aps; Thoustrup & Overgaard Development A/S
Priority date: 2001-09-07
Filing date: 2002-09-06
Publication date: 2003-03-20

Abstract

The invention relates to an automatic method for picking up cuttings from plants, determining whether a given cutting is acceptable according to predefined criterias and placing these cuttings in pots or containers containing a suitable cultivation substrate. The invention furthermore relates to a system for carrying out this method and to a movable and controllable tool for picking up the cuttings with a proper orientation, if necessary providing holes in said cultivation substrate for the cuttings and placing the cuttings in the substrate in a well-defined manner relative to the substrate and the pots, specifically with the upper end of all cuttings placed at an equal height above the upper surface of the substrate.

Description

PICK AND PLACE ROBOT

TECHNICAL FIELD

The present invention relates to a method for collecting cuttings from a conveyor belt or the like and placing these cuttings with proper orientation in containers or pots according to claim 1. The present invention furthermore relates to a tool for use in said method according to claim 5 and an apparatus for implementing said method according to claim 7.

BACKGROUND OF THE INVENTION

The cutting process for propagation of ornamental plants is today either a fully or at least partially manual process, which is consequently time-consuming and hence expensive. Often a number of cuttings of a specific plant are placed in each container or pot. In case of cactus cuttings, 3 to 6 cuttings are often placed in each pot and in case of roses, 4 to 6 cuttings are often placed in each put. The handling of the cuttings often requires great care as the cuttings may be fragile, and damages to the cuttings may result in the cuttings being unable to root when placed in the pot.

In DK 173,107 B1 a method and an apparatus is disclosed, in which each separate segment of a plant is initially placed manually on individual conveyor belts, by means of which the segment on each belt - controlled by a photocell - is conveyed to a position below a gripper-tool comprising a row of suction means pivotally mounted on a shaft extending laterally relative to the conveyor belts. When one section is located beneath each of the suction means, the table carrying the conveyor belts is raised and the sections are taken up by the suction means. After this, these means can be rotated due to their mounting on said laterally extending shaft to a position in which the sections can be inserted into appropriate indentations in a growth medium.

NL 1 ,012,417 discloses a device for the placement of cuttings in trays, the trays being advanced on a conveyor belt. The device comprises a plurality of stations, one of which removes unsuited plants, another of which aligns the usable cuttings after the direction of movement of the conveyor belt and the third of which comprises gripper means mounted for rotation, gripping the cuttings on the conveyor belt and by a suitable rotation of these placing the cuttings in the trays. As in the above document DK 173,107 B1 , the cuttings are conveyed to the gripper means via separate conveyor belts.

The above prior art methods and devices for placing cuttings in bodies of growing substrate suffer from various disadvantages. Thus, the method according to DK 173,107 B1 is not fully automatic but requires manual placement of the individual cuttings on each of the plurality of conveyor belts. Furthermore, the application of a plurality of separate conveyor belts complicates the mechanical construction of the apparatus according to this document.

DISCLOSURE OF THE INVENTION

On the above background it is the object of the present invention to provide an automatic method for picking up cuttings and placing these cuttings with proper orientation in a cultivation substrate in suitable containers or pots.

It is a further object of the present invention to provide an automatic method for detecting defective cuttings so that these defective cuttings are not placed in said pots.

It is a further object of the present invention to provide an apparatus for determining the position and orientation of the cuttings, reorienting the cuttings appropriately if needed to obtain said proper orientation relative to said containers or pots, if necessary preparing holes or indentations for each cutting in said containers or pots and placing the cuttings properly oriented and with the proper depth either directly in said cultivation substrate itself or in said holes or indentations.

It is a further object of the present invention to provide an apparatus for detecting defective cuttings on said conveyor belt. It is yet another object of the present invention to provide a tool specifically for picking up said cuttings, if necessary preparing holes or indentations for these cuttings in material contained in said pots and inserting the cuttings in these holes or indentations.

These and other objects are attained with a method according to the independent claim 1 , a tool according to the independent claim 5 and an apparatus according to the independent claim 6. Various embodiments are defined in the dependent claims.

According to the present invention, there is thus provided a method for picking and placing cuttings of plants comprising the following steps:

- Provision of a plurality of cuttings placed with arbitrary positions and orientations;

- provision of at least one container containing a suitable cultivation substrate; - provision of a movable and controllable pick and place means that can access both said cuttings and said container(s);

- positioning of said pick and place means adjacent to one of said cuttings, the orientation of said pick and place means being such that said cutting assumes a predefined orientation relative to said pick and place means; - picking up said cutting, so that said cutting retains its orientation relative to said pick and place means;

- repetition of the previous two steps a predetermined number of times;

- positioning of said pick and place means at a predetermined position and with a predetermined orientation relative to said container(s); - if necessary using said pick and place means to provide holes or indentations in said material contained in said container(s);

- insertion of at least one of said cuttings either into said cultivation substrate itself or into said holes or indentations.

As an extension of the above method it may be advantageous prior to said step of picking up a cutting to include the following steps:

- deciding whether said cutting is defective; - if said cutting is found to be defective, proceeding to another cutting by returning to said step of positioning said pick and place means adjacent to one of said cuttings.

In this manner the placement of defective cuttings in containers could be prevented. According to one embodiment of the invention, a "defective" cutting is simply a cutting the overall size of which falls outside a predefined range, but it is also conceivable by proper design of the control system to sort cuttings based on other characteristics.

According to the present invention there is furthermore provided a movable and controllable pick and place means which is able both to pick up and retain given cuttings with the proper orientation of the cutting relative to said means and which is furthermore able to provide said holes or indentations in the material in the containers and finally to place the cutting properly oriented and with the proper depth in these holes or indentations.

According to one embodiment of the present invention, said means comprises a pick and place tool movably mounted on a suitable robot and provided with pneumatic means for picking up cuttings and elongated means for providing the holes or indentations. These means are described in more detail in the detailed description of the invention, but it is understood that a person skilled in the art may conceive other means for carrying out the same functions without departing from the scope of the invention as defined by the claims.

One manner of carrying out the controlling of said pick and place means is by using a suitable video camera provided with suitable image processing means to locate the cuttings that for instance are placed on a table or a conveyor means. Once a specific cutting has been located, it is decided whether it is to be accepted as described above and its position and orientation relative to the pick and place tool is determined. Based on this determination, the tool can be positioned and oriented relative to the specific cutting, whereafter the pick and place process can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the accompanying drawings, in which

Figure 1 is an exemplary view of a complete system for carrying out the method according to the invention;

Figure 2 is a detail of the system shown in Figure 1 showing cactus cuttings placed arbitrarily on a conveyor belt, a robot arm holding a pick and place tool according to the invention and containers comprising an array of pots;

Figure 3 is a detail of the system shown in Figure 1 where a number of cuttings have been placed in pots and where the tool contains a further array of cuttings;

Figure 4 is a view of the pick and place tool according to the invention showing means for providing holes or indentations and for picking up and carrying the cuttings; and

Figure 5 is a schematic view of the positioning of a cutting in a pot.

DETAILED DESCRIPTION OF THE INVENTION

In the following, a detailed description of the method for picking up and placing cuttings according to one embodiment of the present invention is given. Furthermore, the main devices of the system for carrying out said method are described in more detail. The various steps of said method is best described by reference to the exemplary views shown in Figures 1 through 3.

Specifically, the method to be described in the following is applied to cuttings of Phyllocactus as apparent for instance from Figure 5, but it is understood that the method, tool and system according to the invention could also be applied for other kinds of cuttings with appropriate modifications, such modifications being obvious to a person skilled in the art.

With reference to Figures 1 through 3, a specific embodiment of the method for picking up and placing cuttings according to the present invention thus comprises the following main steps:

(a) provision of a first movable transport means, for instance in the form of a conveyor belt 1 ; (b) placing cuttings 5 with arbitrary positions and orientations - although preferably not overlapping each other - on said first movable transport means 1 ;

(c) provision of a second movable transport means for instance in the form of a conveyor belt 2;

(d) provision of one or more arrays 3 of pots 4 on said second transport means 2; (e) provision of a movable and controllable pick and place tool 6 that can access both said cuttings 5 on the first transport means 1 and said arrays 3 of pots 4 on said second transport means 2;

(f) displacement of said tool 6 to a position adjacent one of said cuttings 5;

(g) orientation of said tool 6 so that said cutting 5 assumes a predefined orientation relative to the tool 6;

(h) picking up said cutting 5 by appropriate means so that it retains said orientation relative to the tool 6; (i) repetition of the previous steps (f), (g) and (h) a predefined number of times for picking up a predetermined number of properly oriented cuttings 5; (j) displacement of said tool 6 to a predetermined position and with a predetermined orientation relative to said arrays 3 of pots 4; (k) provision of holes or indentations in the material contained in said arrays 3 of pots 4; (I) insertion of said number of cuttings 5 into said holes or indentations.

The above steps (f) and (g) can either be carried out as separate steps as described above or take place simultaneously as a combined displacement/orientation step.

In practice, the method described above can be implemented in a number of ways. For instance said first transport means 1 carrying the cuttings 5 can be driven until a portion of cuttings are brought within the operative region of the pick and place tool 6. Then the first transport means 1 is halted for a sufficient period to enable the tool 6 to empty its operative region of cuttings, whereafter the first transport means is again driven to place a new portion of cuttings within reach of the tool 6. Alternatively, if the operation of the tool 6 is fast enough, it may be possible to drive the first transport means continuously, which may be advantageous from an operational point of view. According to the introduction, it is in practice furthermore often required to place more than one cutting in each pot, and this is of course also possible according to the invention. Alternative arrangements of the pots compared to the one shown in the Figures are of course also possible.

According to a particularly advantageous embodiment of the method according to the invention as described above, it is also possible between the above steps (g) and (h) to include a step of deciding whether the specific cutting found by the tool 6 is defective and if so, to move on to another cutting. If the cuttings are sorted based on overall size as mentioned previously, this sorting can also prevent an attempt to pick up overlapping cuttings, as such cuttings will represent an overall size in excess of the largest acceptable size defined during set-up of the system.

Referring to Figures 2 or 3, the pick and place tool 6 is shown mounted on a robot for movement of the tool in the manner described above. As shown in Figures 2 and 3, and more detailed in Figure 4, the tool 6 according to this embodiment of the invention comprises a row of pneumatic pick-up means 8 provided with suction cups 10 being able to pick up the cuttings 5 by the application of a vacuum or sufficiently low air pressure to each of the specific pick-up means 8 when this is located in the vicinity of the cutting 5. In the above step (h) of the method, the tool 6 is thus placed above the specific cutting to be picked up with one of the pneumatic pick-up means 8 located immediately above and facing the cutting 5, whereupon vacuum is applied to the pick-up means 8. By repeating the steps (f), (g) and (h), the whole array of pick up means 8 on the tool 6 is gradually being provided with cuttings 5.

In the ensuing steps (j), (k) and (I), the array of cuttings 5 is placed in the corresponding array of pots 4. This is done by a displacement of the pick and place tool 6 by means of the arm of the robot 7 to an appropriate position above the array 3 of pots 4. When this position of the tool 5 is reached, the tool 5 is rotated approximately 90 degrees about its longitudinal axis R, whereby the tongues 9 are brought into a position where they face downwardly towards the pots 4. After this, the tool 6 is lowered and the tongues 9 are thereby introduced into the material in the pots 4. When the desired depth of penetration has been reached, the tool 6 is rotated slightly about its longitudinal axis R, whereby the holes or indentations are formed. The tool is again raised to a position where the tongues 9 are located above the pots 4, after which the tool 6 is rotated approximately 180 degrees about the longitudinal axis R to a position, where the vacuum outlets of the pick up means 8, carrying the cuttings 5, are oriented substantially in parallel with the upper plane of the array 3 of pots 4. In this position of the tool 6, those ends of the cuttings 5 that are to be placed at the bottom of said holes or indentations are facing downwards towards the pots 4, and the tool is now finally lowered, whereby the cuttings 5 are inserted into the holes or indentations with a proper depth.

The control of the pick and place tool during the various operations described above can be implemented in the following manner:

A video camera 11 is positioned above the first movable transport means 1 carrying the cuttings 5. According to one specific embodiment of the invention, the camera 11 is a monochrome camera and the first movable transport means is of a light grey colour, whereby the cuttings 5 appear as dark areas on the transport means 1. The transport means 1 is illuminated by a high-frequency diffuse light source 12.

At the commencement of the operation, the transport means 1 is brought to an initial position relative to the camera 11 and an image is recorded by the camera. After suitable digitising of the signal from the camera 11 , the cuttings 5 can for instance be sorted based on the size of each cutting in the picture by comparison of the area of the picture of a specific cutting with predetermined threshold values setting limits for maximum and minimum allowable sizes of cuttings.

Based on the recorded picture of a cutting, the centre of gravity of this cutting in the x_cy_c -plane through the cutting (see Figure 5) is calculated, and then the top 13 of the cutting 5 is determined. Referring to Figure 5, the pick-up point 15 of the tool is then calculated, the pick-up point 15 being located a certain predetermined distance hp (the pick-up height) below the top 13. The pick-up height is the same for all cuttings 5, whereby it is ensured that the tops of these are positioned equally relative to the surface of the material in the pots 4.

The pick-up point of the robot is calculated in the above manner for six of the cuttings on the transport means 1 that satisfies the size requirements. The coordinates of the pick-up point and the rotation of the centreline are loaded into the metrical co-ordinate system of the robot: x-position, y-position, z-position and rotation.

Based on the x, y and z co-ordinates of the pick-up point of a specific cutting the pick and place tool is positioned immediately above a first one of the above six cuttings and based on said rotation the tool is aligned properly with respect to the cutting. The cutting is picked up as described below and the robot proceeds to the next cutting and so on, until the tool has picked up all six cuttings.

Based on information about the position of the different pots 4 (for instance the coordinates of a particular row of six pots in the array 3 of pots 4 into which the cuttings are to be inserted), the tool is now brought into a position above these pots and the indentation and insertion steps (k) and (I) as mentioned above carried out.

After insertion of these six cuttings, the tool picks up six new cuttings and following the same steps as described above either places these cuttings adjacent the first set of cuttings in the same pots or proceeds to a new array of pots.

When the initial portion of the transport means 1 is emptied of acceptable cuttings, a new section of the transport means 1 is brought within reach of the pick and place tool and the series of steps described above are repeated.

Although one specific embodiment of the present invention has been shown and described in the preceding parts of the detailed description, it is understood that a person skilled in the art may conceive other embodiments of the invention without departing from the scope of the invention as defined by the following claims. For instance the invention is not limited to the application of the pneumatic pick-up means 8 provided with suction cups 10 described above but could in case of cuttings from other kinds of plants than the Phyllocactus as described above utilise pick-up means designed to grip appropriately for instance around the stem of the cutting.

REFERENCE NUMERALS AND SIGNS

1. first movable transport means

2. second movable transport means 3. array of pots

4. pots

5. cuttings

6. pick and place tool

7. robot 8. pick-up means

9. tongues

10. suction cups

11. camera

12. light source 13. top of cutting

14. centreline of cutting

15. pick-up point

16. bottom of cutting

17. surface of material in pot 18. control system h_c: height of cutting above the surface of the material in the pot d_c: depth of cutting below the surface of the material in the pot h_p: pick-up height o_t: offset of tool

Claims

CLAIMS:

1. Method for picking and placing cuttings of plants comprising the following steps:

(a) Provision of a plurality of cuttings (5) placed with arbitrary positions and orientations;

(b) provision of at least one container (4) containing a suitable cultivation substrate;

(c) provision of a movable and controllable pick and place tool (6) that can access both said cuttings (5) and said container(s) (4);

(d) positioning of said pick and place tool (6) adjacent to one of said cuttings (5) and with the orientation of said pick and place tool being such that said cutting (5) assumes a predefined orientation relative to the pick and place tool (6);

(e) picking up said cutting (5) by appropriate means (8) so that it retains said orientation relative to said pick and place tool (6);

(f) repetition of step (d) and (e) a predetermined number of times;

(g) positioning of said pick and place tool (6) at a predetermined position and with a predetermined orientation relative to said container(s) (4);

(h) if necessary provision of holes or indentations in said cultivation substrate contained in said container(s) (4);

(i) insertion of at least one of said cuttings (5) either into said cultivation substrate itself or into said holes or indentations.

2. Method for picking and placing cuttings according to claim 1, where said cuttings (5) are placed on first movable transport means (1) and said container(s) is/are placed on second movable transport means (2).

3. Method according to claim 1 where the following steps (j) and (k) are carried out between the said steps (d) and (e): G) deciding whether said one cutting (5) is defective;

(k) if said cutting (5) is found to be defective, proceeding to another cutting by returning to step (d).

4. Method according to claim 3 where a defective cutting is a cutting of an overall size falling outside a predetermined acceptable size region.

5. Pick and place tool for picking and placing cuttings of plants comprising an array of actuable pick-up means (8) for picking up said cuttings (5) and retaining these cuttings (5) with a predetermined orientation relative to said tool (6), where said tool (6) furthermore comprises an array of elongated means (9) for providing said holes or indentations in said cultivation substrate in said containers.

6. Pick and place tool according to claim 5, characterised in that said pick-up means (8) is provided with suction cups (10) for picking up a cutting (5) located adjacent to said pick-up means (8) when these means (8) are pneumatically activated.

7. Apparatus for picking and placing cuttings (5) of plants comprising said pick and place tool (6) according to claim 5 or 6, characterised in that said tool (6) is movable and controllably mounted on a suitable robot (7).

8. Apparatus according to claim 7, characterised in that said robot (7) and said tool (6) are controlled by a camera system (11, 12, 18) comprising image-processing means.

9. Apparatus according to claim 8, where said camera system comprises a camera (11) for recording images of a portion of said cuttings (5) which are to be picked up by said tool (6) and a light source (12) for illuminating said portion of cuttings (5).

10. Apparatus according to claim 9, where said camera (11) is a monochrome video camera.

11. Apparatus according to claim 9, where said light source (12) is a high- frequency diffuse light source.

12. Apparatus according to any of the preceding claims 7 to 11 , where said image-processing means comprises processing means for calculating the coordinates of the centre of gravity of a specific cutting (5) in the x_c-y_c plane based on a recorded image of said cutting (5) and where said processing means based on said co-ordinates of the centre of gravity determines a pick-up point (15) located a predetermined distance (h_p) from the top (13) of the cutting (5).

13. Apparatus according to claim 12, where said image processing means based on said pick-up point (15) determines the height of the cutting (h_c) above the cultivation substrate in said pots (4) and based on this controls the positioning of said pick and place tool (6) above said array (3) of pots (4), so that all cuttings (5) are placed at an equal height (h_c) above the cultivation substrate in the pots (4).