WO2015059021A1

WO2015059021A1 - System and method for extracting buds from a stalk of a graminaceous plant

Info

Publication number: WO2015059021A1
Application number: PCT/EP2014/072193
Authority: WO
Inventors: Harald RÖDEL; Antonio Cesar Azenha; Cassio Da Silva Cardoso Teixeira
Original assignee: Basf Se
Priority date: 2013-10-25
Filing date: 2014-10-16
Publication date: 2015-04-30
Also published as: AR098199A1

Abstract

The present invention is related to a system for extracting buds (8) from a stalk (1) of a graminaceous plant. The system comprises a main detection device (11) for detecting a bud on a stalk; a conveyer (2) for conveying the stalk to the main detection device; and a main cutting device (17) for cutting out a vegetal tissue comprising the bud based on the detected position of the bud; wherein said conveyer comprises pressure roller units (3) arranged at adjacent positions along the longitudinal extension of the stalk for exerting radial forces to the stalk, said pressure roller units are coupled to a control unit (4) for controlling the radial forces exerted by the pressure roller units to said stalk independently of one another so that the stalk is urged in a straight line. Furthermore, the invention relates to a corresponding method that may be carried out by this system.

Description

System and method for extracting buds from a stalk of a graminaceous plant

The present invention relates to a system for extracting buds from a stalk of a graminaceous plant. The system comprises a main detection device for detecting a bud on a stalk, a conveyer for conveying the stalk to the main detection device and a main cutting device for cutting out a vegetal tissue comprising the bud. Furthermore, the present invention relates to a system for extracting buds from a stalk from a graminaceous plant. The method comprises the steps of conveying the stalk to a main detection device, automatically detecting a bud on the stalk by said main detection device and cut- ting out a vegetal tissue comprising the bud based on the detected position of the bud. In particular, the invention relates to a system and a method for extracting buds from a sugar cane stalk.

The seed of sugar cane is a dry one-seeded fruit or caryopsis formed from a single carpel, the ovary wall pericarp being united with the seed-coat testa. The seeds are ovate, yellowish brown and very small, about 1 mm long. Disadvantageously, the seed of sugar cane only germinates under specific environmental characteristics, such as a constant warm and humid climate conditions. Such climatic conditions are not found everywhere sugar cane is grown and therefore germination of sugar cane seed is not always guaranteed. For commercial agriculture, the seed of a sugar cane is not sown or planted, but instead, the cane is propagated vegetatively by planting a stem segment or part of a stalk or culm or seedling.

The stem of sugar cane, as well as the stem of graminaceous plants, comprises sever- al nodes, from which new plants grow. The traditional planting process of sugar cane involves the reservation of an area of the crop to be used as a source of plants for replanting, since the nodes are comprised in the stem. The plants used for replanting are harvested and then cut in segments of approximately 20 to 50 cm, so that at least two nodes are present in each stem segment sett. Cutting the stems is needed to break apical dominance that otherwise causes poor germination when using full length uncut stems. The segments are cut to have at least two buds or at least two nodes; every node gives generally rise to one single bud to assure germination, because not every bud germinates. Current machines used to cut sugar cane segments are not able to identify any characteristic in the stem, and therefore the precise position of the cut sites is determined at random. After cutting, the setts, which have one or more nodes, are disposed horizontally, over one another in furrows of the ploughed soil, which are generally wide at ground level and deep 40 to 50 cm wide and 30 to 40 cm deep, and then lightly covered with soil.

Although this plantation technique is still being used until today, the whole process is relatively inefficient because many segments of two to four nodes have to be used to guarantee the germination. The consequence is that a large area for re-planting needs to be used, and therefore area that could be employed for the crop and production of alcohol or sugar has to be reserved for re-planting. Thus, there is a necessity to increase the efficiency of the planting technique of sugar cane.

In a more recent cultivation method from Syngenta called Plene®, nodes of less than 4 cm in length are separated from the stems, treated with Syngenta seed products and then planted to the field. The method is said to lead to a yield increase of up to 15%. However, the area required for multiplication is still very large. Similar cultivation meth- ods are also described in WO 2009/000398, WO 2009/000399, WO 2009/000400, WO 2009/000401 and WO 2009/000402.

Furthermore, WO 2009/100917 describes a cutting machine and a method for cutting stem segments of a graminaceous plant. According to the method, a characteristic of the stem is identified using a sensor. The sensor is a pressure transducer sensor, a capacitive sensor, an ultrasound sensor, an X-ray sensor, a magnetic sensor or a microwave sensor. The characteristic of the stem is in particular a node. After the node has been identified, the stem is placed in a determined position for cutting, depending on the response of the sensor. The stem is then cut at a particular position depending on the presence of the identified characteristic, i.e. the presence of a node. A similar method is described in WO 2009/100916.

Furthermore, CH 70201 1 A2 describes a further cutting device for sugar cane stalks. In this case, the sugar cane stalk is conveyed in the longitudinal direction to a node detec- tion unit detecting the nodes of the stalk of the sugar cane. A cutting unit is connected to a control unit so that the cutting unit is activated if a node area is positioned within the cutting unit, thereby cutting out a node area.

Moreover, WO 86/06576 describes a method and an apparatus for dividing plant mate- rials. The method and apparatus relates to improvements in the micro propagation of plants. According to this method the plant is scanned to generate an image signal representative of the optically detectable structure. From the image signal, division locations are determined and a corresponding division signal is generated. In particular, the image signal is processed to produce a co-ordinate map of the structure. Based on this co-ordinate map, branch tips and nodes are identified. A cutting machine is then activated responsive to the division signal to divide the plant material at the detected locations. It is the object of the present invention to provide a system and method for extracting buds from a stalk of a graminaceous plant, wherein buds are cut out together with mer- istematic tissue from the stalk so that the buds can subsequently be cultivated and wherein, however, as little material as possible is removed from the stalk. According to the invention, this object has been achieved by a system as defined in claim 1 and a method as defined in claim 13. Further features of this method and system are defined in the dependent claims.

According to the system of the present invention, the conveyer comprises pressure roller units arranged at adjacent positions along the longitudinal extension of the stalk for exerting radial forces to the stalk, said pressure roller units are coupled to a control unit for controlling the radial forces exerted by the pressure roller units to said stalk independently of one another so that the stalk is urged in a straight line. In terms of the present invention, "stalk" or "stem" is the main trunk of the graminaceous plant, specifically a primary plant axis that develops buds and shouts. Usually, the stalk is essentially cylindrical. The cross section of the stalk is essentially ring- shaped having essentially a circular periphery. Furthermore, a longitudinal axis is defined to cross the centre of the ring shaped cross section of the stalk perpendicular. Preferably the stalk has at least a diameter of 40 mm.

"Node" is the location in the stalk where the shoot, bud or gemma is formed in a graminaceous plant. "Shoot", "bud" or "gemma" is the embryo, spore or germ of a graminaceous plant.

A "removed bud" or a "bud cut out" in the context of the present invention refers to a bud which also contains meristematic tissue. For example, this term includes a bud plus a small section of the node to which it is attached. This term does however not encompass the whole node with the bud. Typically, the removed bud is a "bud chip", i.e. an essentially round or oval disc-shaped cutting of the stalk containing the bud and some meristematic tissue; typically of a diameter of ca. 1 to 5 cm, preferably 1 to 3 cm, more preferably 2 to 3 cm. Diameter in the context of an oval shape refers to the longest extension of the oval. The bud chip may also have a square cross section. In this case, one edge is dimensioned of ca. 1 to 5 cm, preferably 1 to 3 cm, more preferably 2 to 3 cm, in particular the square cross section is dimensioned 20 mm x 20 mm.

According to the system of the present invention any curve of the stalk may be correct- ed. The extension of a stalk may deviate from an ideal straight line. However, an exact detection of the position of a bud can be carried out more accurately if the stalk is straight. According to the system of the present invention the stalks conveyed to the main detection device are brought into a straight line. Therefore, straight stalks are provided if the stalks are originally not straight. Thus, the detection of the buds on the stalk by the main detection device can be improved. Furthermore, the precise cutting of the vegetal tissue comprising the bud may be improved so that as little material as possible is removed from the stalk. It has been experienced that the natural irregularities of the stalk deteriorates the detection of the buds as well as the removal of the vegetal tissue comprising the buds. This problem has been overcome by the particular conveyer used according to the system of the present invention.

According to one embodiment, the pressure roller units comprise rollers for conveying the stalk in the longitudinal direction of the stalk and for exerting the radial forces to the stalk. In particular, these rollers are rotated by one or more drive motors, for example by step motors. Therefore, the rollers provide two functions: on the one hand, the driven rotation of the rollers conveys the stalk in the longitudinal direction. On the other hand, the rollers exert radial forces to the stalk independently of one another. In this case, the radial direction is defined based on the basically cylindrical shape of the stalk. The radial direction is, therefore, perpendicular to the direction of the longitudinal axis of the stalk.

In particular, the rotation axis of each roller is perpendicular to the longitudinal extension of the stalk to be conveyed and the radial force exerted by each roller is directed perpendicular to the longitudinal extension of the stalk to be conveyed as well as per- pendicular to the axis of the pressure roller.

According to a further embodiment, the rollers are rubber and/or polymer coated in order to convey the stalk in the longitudinal direction by a friction force. A rubber or polymer coating can provide a very precise control of the stalk by the rollers without any slippage.

The radial forces exerted to the stalk by the rollers are controlled to urge the stalk in a straight line as well as to provide a friction between the stalk and the rollers that is large enough to convey the stalk in the longitudinal direction of the stalk. According to a further embodiment, each pressure roller unit comprises a pneumatic spring. Such pneumatic spring may be a metal bellow filled with compressed gas. Such springs may be used as an alternative to a metal wire spring.

According to a further embodiment, each pressure roller unit comprises a guided cylinder that is coupled to the roller, said guided cylinder is actuated by the pneumatic spring. In particular, the control unit may be coupled with a valve for actuating the pneumatic spring in order to control the force exerted to the guided cylinder and there- by to the roller. In fact, the guided cylinder moves the roller against the stalk in order to exert the radial force to the stalk.

According to a further embodiment, the main detection device comprises an analysing unit for computing the longitudinal position of the bud in the longitudinal direction of the stalk and the circumferential angle position of the bud on the stalk, said longitudinal position and circumferential angle position defining the position of the bud.

According to the system of the present invention not only the position of a bud in the longitudinal direction of the stalk can be detected but also the angel position of the bud. The vegetal tissue comprising the bud may be cut out based on the longitudinal position of the bud as well as the circumferential angel position of the bud on the surface of the stalk, so that the extraction of the bud can be carried out very accurately.

Usually, only the longitudinal position of the bud is detected. Such detection may be sufficient if a whole node is cut out from the stalk. However, if only a part of the node, i.e. a vegetal tissue that comprises the bud and that contains meristematic tissue, is extracted and not the whole node it is important not only to detect the longitudinal position of the bud but also the circumferential angel position of the bud so that the vegetal tissue comprising the bud can exactly be cut out comprising as much vegetal tissue as necessary but as a little vegetal tissue as possible.

According to a further embodiment, the system comprises at least one turning unit for rotating the stalk around its longitudinal access. This turning unit may also comprise one or more rollers. However, the axes of these rollers are aligned to the longitudinal axis of the stalk, i.e. the axis are parallel to the longitudinal axis of the stalk.

The at least one turning unit may be coupled to the control unit. The control unit may be coupled to the main detection device. In this case, the control unit may be adapted to control the turning unit to rotate the stalk around its longitudinal axis so that a straight line on a cross section of the stalk that passes through the centre of the stalk and the position of the centre of the bud on the surface of the stalk is aligned with a predetermined direction. This predetermined direction may coincide with an axis of a main cutting device for cutting out vegetal tissue comprising the bud. Therefore, the bud on the stalk may be positioned by the pressure roller units as well as the turning unit precisely with respect to a main cutting device so that the bud may be cut out with as little surrounding material of the stalk as possible.

According to an embodiment, the main cutting device is a punching device. In particu- lar, the stalk and the punching device may be rotated relative to each other around the longitudinal axis of the stalk so that the axis of the punching device, i.e. the direction in which the blade of the punching device is moved, coincides with a straight line that passes through the centre of the stalk and through the position of the centre of the bud. In order to cut out as less vegetal tissue as possible, but as much tissue as necessary, the extension of the blade of the punching device is smaller than the cross section dimension of the stalk. However, the extension of the blade is sufficient to cut out vegetal tissue that comprises the whole bud and enough meristematic tissue that is necessary for cultivating the graminaceous plant from the bud. According to an embodiment of the system of the present invention the main detection device comprises at least one laser unit for irradiating the stalk with a laser beam. Furthermore, the detection device comprises at least one optical sensor for detecting the reflected electromagnetic radiation of the laser beam. In this case, the analyzing unit may be adapted to compute the position of the bud by analyzing the topography of the stalk surface based on the detected reflected electromagnetic radiation of the laser beam. In order to analyze the whole circumferential surface of the stalk simultaneously two or more laser devices and optical sensors may be used.

In particular, the optical sensor may be a camera, preferably a camera obtaining imag- es that may be analyzed using laser triangulation for extracting the shape of the surface of the stalk.

According to a further embodiment, the system comprises a further cutting device having a blade that is moved in a direction perpendicular to the longitudinal axis of a stalk for transversely cutting the stalk into stalk segments.

Furthermore, the present invention is directed to a method for extracting buds from a stalk of a graminaceous plant. The method comprises the steps of conveying the stalk to a main detection device, automatically detecting a bud on the stalk by the main de- tection device and cutting out a vegetal tissue comprising the bud based on the detected position of the bud. According to the present invention, the step of conveying comprises exerting radial forces to the stalk at adjacent positions along the longitudinal extension of the stalk, the exerted forces being controlled independently of one another to urge the stalk in a straight line.

The method of the present invention may be carried out by the system of the present invention as described above. The method therefore provides the same advantages as the above described system.

In particular, the radial forces are exerted to the stalk by rollers, the rollers also conveying the stalk in the longitudinal direction of the stalk. Furthermore, the position of the rollers is detected for controlling the radial forces exerted to the stalk to bring the stalk in a straight line.

According to one embodiment, the step of detecting the bud on the stalk comprises irradiating the stalk with a laser beam and detecting the reflected electromagnetic radiation of the laser beam by an optical sensor. Therefore, the bud on the stalk is detected optically. In particular, the optical sensor may be a camera. Using a laser beam for de- tecting the bud provides a reliable and cost-effective detection method.

In particular, a laser line is irradiated on the surface of the stalk while the stalk moves in its longitudinal direction. The laser line extends perpendicular to the longitudinal direction of the stalk so that the stalk moves through a light curtain formed by the laser beam. Therefore, the laser beam scans the surface of the stalk while the stalk moves in its longitudinal direction.

In order to detect the whole surface of the stalk, the stalk may be irradiated with two or three or even more laser beams and two or more optical sensor may be used for de- tecting the reflected electromagnetic radiation of the laser beams.

According to a further embodiment, the step of detecting the bud on the stalk comprises computing the topography of the stalk based on the detected reflected electromagnetic radiation of the laser beam. As a bud forms a protrusion on the surface of the stalk, it may be reliably detected by analyzing the topography of the surface of the stalk.

According to a further embodiment, data indicating the detected position of the bud on the stalk are transferred to a main cutting device. The actual position of the bud relative to a fixed point in space is calculated based on the data indicating the detected position of the bud on the stalk and based on data indicating a movement of the stalk. Therefore, a movement of a stalk comprising a bud which position has been detected is measured so that the exact position of the bud can be calculated after the detection of the bud irrespective of any manipulations that are carried out with the stalk. Thus, data are available indicating at any time the position of the detected bud in space.

In particular, the position of the bud relative to a main cutting device is calculated based on data indicating the detected position of the bud on the stalk and based on data indicating movement of the stalk comprising the bud. Thus, the vegetal tissue comprising the bud may be cut out very accurately.

According to a further embodiment, the stalk or a segment of the stalk is positioned relative to the main cutting device based on data indicating the detected position of the bud on the stalk and based on data indicating a movement of the stalk so that vegetal tissue comprising the bud is cut out by the main cutting device. For example, a turning unit may rotate the stalk around its longitudinal access. This turning unit may also comprise one or more rollers. According to a further embodiment, the step of cutting out the vegetal tissue comprising the bud comprises punching out a vegetal tissue in the direction of a straight line that passes trough the centre of the stalk and the position of the centre of the bud on the surface of the stalk. The axis of the punching action coincides therefore with the radial direction of the stalk crossing the centre of the bud on the surface of the stalk.

It is noted that the circumferential angel positions of the buds on one stalk is not always the same. Therefore, the straight line that passes through the centre of the stalk and through the position of the centre of the bud on the surface of the stalk is not the same for all buds of one stalk. The angel of the straight line may vary for different buds on the stalk. Therefore, according to an embodiment of the invention, the stalk and a punching device may be rotated relative to each other around the longitudinal axis of the stalk so that the axis of the punching device, i.e. the direction in which the blade of the punching device is moved, coincides with the straight line that passes through the centre of the stalk and through the position of the centre of the bud. In other words, the axis of the punching action coincides with the radial direction of the stalk crossing the centre of the bud on the surface of the stalk. By this measure the vegetal tissue comprising the bud can be extracted as exactly as possible. In order to cut out as less vegetal tissue as possible, but as much tissue as necessary, the extension of the vegetal tissue that is punched out is smaller than the cross section dimension of the stalk. However, the extension of the vegetal tissue punched out comprises the whole bud and enough meristematic tissue that is necessary for cultivating the graminaceous plant from the bud. In particular, the vegetal tissue punched out is thus not comprised the whole note comprising the bud.

However, it is imperative that the buds are removed in such away that the removed buds comprise meristematic tissue. The meristematic tissue is known to those skilled in the art and can be located by its position close to the node. The presence of meristematic tissue enables the removed buds to form roots and produce seedlings. For this purpose the buds are removed close to the node from which they originate and preferably comprise or, in other words, are attached to a part of the node.

The present invention further relates to the use of the above-described system for extracting buds from a stalk of a graminaceous plant, in particular a stalk of an adult sugar cane plant. bodiments of the present invention are now describes with reference to the figures.

Figure 1 shows schematically the structure of an embodiment of the system for extracting buds from a stalk according to the present invention; Figure 2 shows a top view of a variant of the embodiment of the system shown in figure 1 for extracting buds from a stalk according to the present invention;

Figure 3 shows a cross section of a stalk with a bud; Figure 4 shows a perspective view of the stalk shown in figure 3;

Figure 5 shows a cross section of a stalk half;

Figure 6 shows the stalk half shown in figure 5 and a blade of a punching device;

Figure 7 shows a perspective view of a part of the system shown in figure 2;

Figure 8 shows another perspective view of a part of the system shown in figure 2; Figure 9 shows a detailed view of an embodiment of the system of the present invention for illustrating the function of the pressure roller units;

Figure 10 shows another view of the detailed view of the system shown in figure 9, and

Figur 1 1 further illustrates the function of a pressure roller unit according to the present invention. The first embodiment of the system and the method of the present invention is now described with reference to the figures:

Sugar cane plants are removed by chopping off with a machete in a height of approximately 2 m to 2.5 m. The removed top part of the sugar cane plants is disregarded. The below, remaining stalks are removed from the field by cutting them off closely above the ground. The stalks are cleaned and prepared for the extraction of the buds.

As shown in figure 1 , such stalk 1 is placed on a conveyer. The conveyer comprises a belt 2 and pressure roller units 3 for conveying the stalk 1 in direction A. The pressure roller units 3 are controlled by a conveyer control unit 4. The conveyer may move stalks 1 without slippage.

In the variant of the first embodiment shown in figure 1 the stalk 1 is placed on the beginning of the conveyer. By the transport of the conveyer the stalk 1 then enters an initial detection and cutting device 6. The initial detection and cutting device 6 is connected with the conveyer control unit 4 and a signal indicating that a stalk 1 enters the initial detection and cutting device 6 is transferred to the conveyer control unit 4.

The conveyer control unit 4 transfers data indicating the position of each stalk 1 on the conveyer to a main control unit 5. Therefore, main control unit 5 comprises data indicating at each time the position of each stalk 1 on the conveyer.

The initial detection and cutting device 6 firstly detects the position of the buds of stalk 1 roughly. In particular, only the circumferential angel position is roughly detected. Usually the stalk 1 comprises nodes that are ring shaped and spaced apart from each other in the longitudinal direction of the stalk 1 . Each node comprises one bud 8. The buds 8 of consequent nodes are located approximately on opposite directions of the stalk 1. Therefore, every second bud 8 extends approximately in the same first direc- tion and every second other bud 8 extends in another direction being 180° apart from the first direction.

Figures 3 and 4 show a cross section and a perspective view of a stalk 1 . However, the stalk 1 is only shown partly comprising one node 24 including one bud 8. The stalk 1 is cut in longitudinal direction L at plane C that is perpendicular to straight line S that passes through the centre M of the stalk 1 and the position of bud 8. However, it is mentioned that not all buds have the same circumferential angel position on the surface of stalk 1 so that every straight line S of each bud 8 is exactly perpendicular to plane C.

The initial detection and cutting device 6 rotates stalk 1 relative to an initial cutting device so that stalk 1 is cut into two halves 7 in the direction of plane C. The cross section of one half 7 is shown in figure 5.

The stalk halves 7 are then automatically placed on the conveyer so that the stalk halves 7 are placed adjacent to each other and oriented so that the cut faces of both halves 7 are oriented downwards. Accordingly, the buds 8 on each stalk half 7 are oriented essentially upwards.

Figure 2 shows another variant of the first embodiment of the system of the present invention. It is similar to the variant shown in figure 1. However, it does not comprise an initial detection and cutting device 6 but only an initial cutting device 10. Initial cutting device 10 comprises a cutting blade that is oriented vertically in the longitudinal direc- tion of the stalks 1 for cleaving stalks 1 . In this case a user feeds the stalks 1 in a particular orientation to the initial cutting device 10 so that the buds extends to the right and to the left so that the stalks 1 are cleaved in a plane that corresponds to plane C shown in figures 3 and 4. Therefore, the embodiment shown in figure 2 only differs from the embodiment shown in figure 1 , in that the orientation of the cut of the stalk 1 in longitudinal direction L of the stalk 1 is not determined automatically but manually. Therefore, the following description of the embodiment is the same for both variants so that reference is made to figure 1 as well to figure 2.

The stalk halves 7 are then conveyed further in direction A whereby the stalk halves 7 are urged by pressure roller units 3 essentially in a straight line, as it is described in detail later. The stalk halves 7 are then feed to main detecting device 1 1. Main detecting device 1 1 comprises a laser unit 12, an optical sensor 13, for example a camera, and an analyzing unit 14 that is connected to the laser unit 12 and the optical sensor 13. The laser unit 12 irradiates the upper surface of stalk halves 7 with a laser beam. In particular, the laser beam may irradiate a line on the upper surface of the stalk halves 7 in transverse direction while the stalk halves 7 move in its longitudinal direction L so that the laser beam scans the upper surfaces of the stalk halves 7. In the present embodiment the laser unit 12 irradiates a red laser line vertically down on the upper sur- face of stalk halves 7.

In the present embodiment, the optical sensor 13 is a camera. It detects visual images of the electromagnetic radiation of the laser beam reflected by the upper surface of the stalk halves 7. The images are transferred to analyzing unit 14 that is able to compute the three-dimensional shape of the surface of stalk halves 7. In particular, the topography of the surface of the stalk halves 7 are computed by a pixel-by-pixel analysis of the detected reflected electromagnetic radiation of the laser beam. The topography may for example be computed according to the laser triangulation principal. Alternatively or in addition the colour variation of the surface of the stalk halves 7 may be analyzed. Furthermore, thermography may be used to analyze the surface of the stalk halves 7.

The topography computed by the analyzing unit 14 is further analysed so that a bud 8 on a stalk half 7 is identified. Subsequently, the position of the bud 8 in longitudinal direction L is determined as well as the circumferential angel position a of the bud 8 on the cross section of the stalk half 7. The position of the bud 8 in the longitudinal direction L and the circumferential angel position a of the bud 8 on the cross section of the stalk 7 define the position of the bud 8 on the stalk half 7. As mentioned above, the position of the bud 8 is not always exactly vertically over the centre M of the stalk 1 that has formed stalk half 7 so that the circumferential angel position a of the buds 8 of one stalk half 7 vary.

Figures 5 and 6 show the definitions of the position of a bud 8 on the surface of a stalk half 7. Stalk half 7 is oriented so that the cut faces 25 lay on a horizontal plane H that is identical to plane C. Furthermore, a vertical line V is shown that extends perpendicular to horizontal plane H and crossing centre M of stalk 1 and stalk half 7. The circumferential angel position a of bud 8 is defined as the angel on a cross section of stalk half 7 between a straight line S passing centre M and the centre position of bud 8 on the one hand and the vertical line V on the other hand as shown in figure 5.

Figures 7 and 8 show a more detailed view of section 23 of the system described with reference to figures 1 and 2. However, an embodiment is shown that processes the stalk halves 7 sequentially and not next to each other as described above. However, all features shown in figure 7 and 8 may also be used in connection with the parallel processing of stalk halves 7 as described above. As shown in detail in figures 7 and 8, the stalk halve 7 oriented so that the cut faces 25 show downwards is supported by pressure roller units 3 that may be driven by motor 31 . Motor 31 is controlled by control unit 4. The pressure roller units 3 transport the stalk halves 7 in direction A. Furthermore, it can be seen in particular in figure 8 that the pressure roller units 3urge stalk half 7 in a straight line. The pressure roller units 3 are mounted on a machine table 29 that comprises a recess so that the pressure roller units 3 may support stalk halves 7.

Returning to figures 1 and 2, data as to the position of a detected bud 8 on a stalk half 7, i.e. the longitudinal position and the circumferential angel position α , are transferred from the analysing unit 14 to main control unit 5. Once, a bud 8 has been detected on the right stalk half 7 as well as the left stalk half 7, main control unit 5 controls the pressure roller units 3 of the conveyer so that the stalk halves 7 are moved relative to each other in the longitudinal direction L so that the detected buds 8 of the stalk halves 7 are positioned next to each other.

Subsequently, both stalk halves 7 are further feed on conveyer to a further cutting device 32. Cutting device 32 cuts stalk halves 7 positioned next to each other into stalk segments 15, so that each segment 15 comprises only one bud 8. As shown in figure 2 buds 8 of adjacent stalk segments 15 are positioned next to each other. The length of a stalk segment 15 corresponds approximately to the distance of two buds 8 in the longitudinal direction L.

In general, the stalk segments 15 are then feed or positioned by a device that grips or fasts the stalk segments 15 into a defined position with respect to a main cutting device. In the present case, stalk segments 15 are feed to a turntable 16. Turntable 16 comprises a motor 27 that can rotate turntable 16 around vertical axis 18. The rotation of turntable 16 is controlled by the turntable control unit 28 that transfers data indicating as to how turntable 16 is rotated to main control unit 5. Therefore, main control unit 5 may determine the position of stalk segments 15 as well as the position of buds 8 at any time.

As it can be seen in figure 2, main control unit 5 turns turntable 16 so that stalk seg- ments 15 are moved to a punching device 17 that forms in the embodiment the main cutting device. If buds 8 of stalk segments 15 are positioned directly under punching device 17 the main control unit 5 stops turntable 16. The punching device 17 comprises a unit that grips and fasts stalk segments 15. Based on data indicating the circumferential angel position a of each bud 8 on each stalk segment 15, each stalk segment 15 is rotated around the longitudinal axis L by the griping and fasting unit of the punching device 17 or by other means as described later so that each bud 8 is exactly oriented vertically upwards. In other words, the straight line S passing the centre M of stalk segment 15 and the centre position of bud 8 is oriented vertically. Two tubular blades 26 of punching device 17 are then moved vertically downwards to punch out a vegetal tissue 19 comprising the bud 8. Therefore, a so-called "bud chip" 19 is cut out from each stalk segment 15.

As two stalk segments 15, each comprising one bud 8, are positioned next to each other, each stroke of punching device 17 results in two bud chips that are cut out and that are collected.

According to another variant of the first embodiment not the stalk segments 15 are rotated around the longitudinal axis L relative to the punching device 17 but the axis P of each blade 26 of punching device 17 is rotated relative to each stalk segment 15 around the axis L of the respective stalk segment 15 so that the axis P of each blade 26 of punching device 17 coincides with the straight line S crossing the centre M of stalk segment 15 and the centre position of the bud 8. This rotation of the tubular blades 26 of punching device 17 is also controlled by main control unit 5 based on the circumferential angel position a of each bud 8 on stalk segments 15. As shown in fig- ure 6, the tubular blade 26 cuts out the bud chip 19.

It is pointed out that the extension of the bud chips 19 is much smaller than the extension of the cross section of a stalk half 7. However, each bud chip 19 contains the bud 8 and meristematic tissue. In particular, the extracted bud 8 is not bound to the com- plete node 24 from which it originates, but just to a small disc- or chip-like portion of the stalk 1. As the punching device 17 is moved in the radial direction of the stalk 1 , even if stalk 1 comprises buds 8 that are not exactly oriented parallel, the method and the system of the present invention provides bud chips 19 that have cut faces oriented per- pendicular to a tangent on the surface of a cylindrical representation of the stalk 1 at the position of the bud 8.

The punching device 17 may use a pneumatic or a light puncher. Furthermore, a laser beam may be used for cutting out bud chips 19.

As shown in figure 2, after cutting out bud chips 19 turntable 16 is further rotated to move the rest 20 of stalk segments 15 from which the bud chips 19 have been cut out to a container 21. Container 21 feeds the rest 20 of the stalks 1 to a mill for crushing the rest 20 of stalks 1 . Therefore, he remaining stalks 1 are made available for further processing.

The whole system shown in figure 2 is arranged within a 20 ft. standard sea container 22 so that the system may easily be transported to the desirable location for extracting the buds 8.

The above-described method and system is used to extract buds 8 from adult sugar cane stalks 1 . However, buds 8 from stalks 1 of other graminaceous plants may also be extracted using the method and system described above.

In the following, a second embodiment of the system and the method of the present invention is described:

The second embodiment differs from the above-described first embodiment in that the stalk 1 is not cut in the longitudinal direction into stalk halves 7, but stalk 1 is processed as a whole. It may only cut transversely into segments but not longitudinally. Therefore, the system according to the second embodiment does neither comprise the initial detection and cutting unit 6 nor the initial cutting unit 10. Instead the whole stalk 1 is urged by pressure roller units 3 into a straight line as described later and feed to the main detection unit 1 1.

However, the main detection unit 1 1 of the second embodiment differs from the main detection unit 1 1 of the first embodiment in that more than one laser unit 12 and more than one optical sensor 13 are used so that the surface of the stalk 1 may be analyzed on the whole circumference. For example, three lasers units 12 and optical sensors 13 may be used that are positioned around stalk 1 on the conveyer. Alternatively, the main detection unit 1 1 is identical to detection unit 1 1 of the first embodiment but during detection the stalk 1 is rotated around the longitudinal axis L so that buds 8 may be detected irrespective of its circumferential angel position. Such rotation of stalk 1 during detection by the main detection unit 1 1 is also detected and data thereto are transferred to main control unit 5. Therefore, the longitudinal position as well as the circumferential angel position a of all buds 8 on stalk 1 can be identified and transferred to punching device 17.

Furthermore, the step of moving the stalks 1 in a longitudinal direction L so that the detected buds 8 are positioned next to each other is omitted as in this case two stalks 1 are not positioned next to each other. According to the second embodiment, a stalk segment is formed by cutting device 32, too, and the stalk segment is rotated on turntable 16 around its longitudinal axis L so that the straight line S crossing the centre M of stalk 1 and the centre position of bud 8 is exactly orientated vertically. Therefore, vertical movement of a blade 26 of punching device 17 cuts out one bud chip 19.

All other steps described with reference to the first embodiment may also be carried out analogously in the second embodiment of the system and method of the present invention.

In the following, the conveyer comprising the pressure roller units 3 will be described in more detail. The conveyer and the pressure roller units 3 as described in the following may be used in connection with the first and second embodiments as described above. Figures 9 and 10 show a more detailed view of section 23 of the system described with reference to figures 1 and 2. It is an alternative to the structure of the section 23 as shown in figures 7 and 8. In particular, the structure as shown in figures 9 and 10 is used in connection with the second embodiment in which the stalk 1 is processed as a whole.

The conveyer as shown in figures 9 and 10 comprises pressure roller units 3 arranged at adjacent positions along the longitudinal extension of the stalk 1 . The distance between the pressure roller units 3 may be in the range of 5 cm to 30 cm depending on the length of the stalk 1 and its curvature. The pressure roller units 3 comprise rollers 9. The rollers 9 are coated by a polymer or by rubber to provide a large friction force when contacting the surface of the stalk 1 . The rollers 9 are pivotally mounted on an axle and driven by a first drive motor 30. Furthermore, each pressure roller unit 3 comprises a guided cylinder 33 that is movably mounted within a housing 34. The guided cylinder 33 is coupled to the axle that supports the roller 9. By movement of the guided cylinder 3 the roller 9 can be brought into contact with the surface of the stalk 1.

Moreover, each pressure roller unit comprises a pneumatic spring 35 within the housing 34. The pneumatic spring 35 is coupled to the conveyer control unit 4. Therefore, conveyer control unit 4 can initiate movement of each guided cylinder 33 by means of each pneumatic spring 35. Furthermore, conveyer control unit 4 can control for each pressure roller unit 3 the radial force that each roller 9 exerts to stalk 1 independently.

Figure 1 1 shows the geometry of a roller 9 relative to stalk 1 . The roller 9 contacts the circumferential surface of stalk 1 and is urged by force F against stalk 1. In order to convey the stalk 1 in the direction of the arrow A in the longitudinal direction of the stalk 1 , the roller 9 is driven by first drive motor 30 in the direction of arrow B. Therefore, the rotation axis of the roller 9 is perpendicular to the longitudinal extension of the stalk 1 as well as the conveying direction A. Furthermore, the radial force F exerted by roller 9 to the stalk 1 is directed perpendicular to the longitudinal extension of the stalk 1 as well as perpendicular to the axis of the roller 9.

Returning to figures 9 and 10 it can be seen that the pressure roller units 3 are arranged at adjacent positions along the longitudinal extension of the stalk 1 as well as on different angle positions at one particular longitudinal position of the stalk 1 . In particular, at one longitudinal position of the stalk 1 , three rollers 9 contact the stalk 1 and exert a radial force F to the stalk 1 . The angle between the three rollers 9 at one longitudinal position of the stalk 1 may be 120°. The position of each roller 9 relative to the surface of the stalk 1 as well as the radial force F exerted by each roller 9 is controlled by the guided cylinders 33 and the pneumatic springs 35 of the pressure roller units 3 in connection with the conveyer control unit 4. The position of the rollers 9 and the ex- erted forces F are controlled by conveyer control unit 4 such that the stalk 1 is urged in a straight line. Therefore, by means of the pressure roller units 3 in connection with the conveyer control unit 4 the stalk 1 is brought in a straight line and at the same time conveyed in direction A to convey the stalk 1 to the main detection unit 1 1 . In the following, an alternative to the provision of the turntable 16 as described in the embodiments shown in figures 1 and 2 is described. In this case the system does not comprise the further cutting device 32 as well as the turntable 16. Instead, the stalk 1 is positioned as a whole for the extraction of the buds 8. As described above, the precise position of a detected bud 8 on the stalk 1 , i.e. the longitudinal position and the circum- ferential angle position, is present in main control unit 5. In the alternative shown in figures 9 and 10 the extraction device that may also be a punching device 17 is positioned at the same longitudinal position of stalk 1 as the main detection unit 1 1 or next to this main detection unit 1 1.

In order to position the buds 8 exactly relative to punching device 17 with respect to the circumferential angle position turning units 36 are provided. The turning units 36 are similar to the pressure roller units 3. However, the rollers 37 have a different orientation. The axle of rollers 37 is parallel to the longitudinal extension of the stalk 1 . Fur- thermore, the rollers 37 may also be moved in the direction of the surface of the stalk 1 by means of a guided cylinder 38 of each turning units 36. The guided cylinders 38 of turning units 36 are coupled with main control unit 5, so that the stalk 1 can be rotated around its axis by means of rollers 37 that are also driven by a second drive motor such as a step motor. Therefore, the buds 8 can be positioned directly in the movement direction of the punching device 17. In other words, the main control unit 5 controls turning units 36 to rotate the stalk 1 around its longitudinal axis so that a straight line on a cross section of the stalk 1 that passes through the center of the stalk 1 and the position of the center of the bud 8 on the stalk 1 is aligned with the movement direction of the punching device 17.

The operation of the system as described with reference to figures 9 to 1 1 is as follows:

Firstly, the conveyer control unit 4 controls the pressure roller units 3 so that rollers 9 are in pressure contact with the surface of stalk 1 . Rollers 9 are then rotated by first drive motors 30 so that the stalk 1 is moved forward. Simultaneously, the radial position of rollers 9 is detected with respect to the longitudinal axis of the stalk 1 . The conveyer control unit 4 then controls the radial position of rollers 9 independently from each other, thereby exerting a radial force to the stalk 1 for bringing stalk 1 in a straight line. Furthermore, the position of the nodes of stalk 1 is detected. Once a node is positioned at the main detection unit 1 1 , stalk 1 is rotated around its axis by means of turning units 36. During this rotation, the position of the buds 8 is detected. The detected bud 8 is then positioned within the movement direction of the punching device 17 by means of turning units 36. Once the bud 8 has been positioned in this way, the rotation of stalk 1 as well as the forward movement of stalk 1 is stopped. Bud 8 is then extracted by punching device 17. These steps are repeated until the last bud is extracted. List of reference signs:

1 stalk

2 belt

3 pressure roller unit

4 conveyer control unit

5 main control unit

6 initial detection and cutting device

7 stalk half

8 bud

9 rollers

10 initial cutting device

1 1 main detection unit

12 laser unit

13 optical sensor, camera

14 analyzing unit

15 stalk segment

16 turntable

17 punching device

18 axis

19 bud chips, vegetal tissue with bud

20 rest of stalk

21 container

22 standard sea container

23 section of the system

24 node

25 cut faces

26 blade of punching device

27 motor

28 turntable control unit

29 machine table

30 first drive motor

31 motor

32 cutting device

33 guided cylinder

34 housing

35 pneumatic spring

36 turning units

37 rollers

38 guided cylinder

Claims

1 . System for extracting buds from a stalk of a graminaceous plant comprising:

a main detection device for detecting a bud on a stalk;

a conveyer for conveying the stalk to the main detection device; and a main cutting device for cutting out a vegetal tissue comprising the bud based on the detected position of the bud;

wherein said conveyer comprises pressure roller units arranged at adjacent positions along the longitudinal extension of the stalk for exerting radial forces to the stalk, said pressure roller units are coupled to a control unit for controlling the radial forces exerted by the pressure roller units to said stalk independently of one another so that the stalk is urged in a straight line.

2. System according to claim 1 , wherein said pressure roller units comprise rollers for conveying the stalk in the longitudinal direction of the stalk and for exerting the ra- dial forces to the stalk.

3. System according to claim 1 o 2, wherein said rollers are rotated by one or more drive motors.

4. System according to any one of the preceding claims, wherein the rotation axis of each roller is perpendicular to the longitudinal extension of the stalk to be con- veyed and wherein the radial force exerted by each roller is directed perpendicular to the longitudinal extension of the stalk to be conveyed and perpendicular to the axis of the pressure roller.

5. System according to any one of the preceding claims, wherein the rollers are rubber and/or polymer coated in order to convey the stalk in the longitudinal direction by a friction force.

6. System according to any one of claims 2 to 5, wherein said control unit is adapted to detect the position of the rollers in order to control radial forces exerted to the stalk to bring the stalk in a straight line.

System according to any one of the preceding claims, wherein each pressure roll¬

er unit comprises a pneumatic spring.

8. System according to claim 7, wherein each pressure roller unit comprises a guided cylinder that is coupled to the roller, said guided cylinder is actuated by the pneumatic spring.

9. System according to any one of the preceding claims, wherein the main detection device comprises an analyzing unit for computing the longitudinal position of the bud in the longitudinal direction of the stalk and the circumferential angle position of the bud on the stalk, said longitudinal position and circumferential angle position defining the position of the bud.

10. System according to any one of the preceding claims, wherein the system comprises at least one turning unit for rotating the stalk around its longitudinal axis.

1 1 . System according to any one of the preceding claims, wherein said at least one turning unit is coupled to the control unit and said control unit is coupled to the main detection device, said control unit is adapted to control the turning unit to rotate the stalk around its longitudinal axis so that a straight line on a cross section of the stalk that passes through the centre of the stalk and the position of the centre of the bud on the surface of the stalk is aligned with a predetermined direction.

12. System according any one of the preceding claims, wherein the main detection device comprises at least one laser unit for irradiating the stalk with a laser beam and at least one optical sensor for detecting the reflected electromagnetic radiation of the laser beam.

13. Method for extracting buds from a stalk of a graminaceous plant comprising the steps of:

conveying the stalk to a main detection device;

automatically detecting a bud on the stalk by said main detection device; and

cutting out a vegetal tissue comprising the bud based on the detected position of the bud;

wherein the step of conveying comprises exerting radial forces to the stalk at adjacent positions along the longitudinal extension of the stalk, said exerted forces being controlled independently of one another to urge said stalk in a straight line.

14. Method according to claim 13, wherein radial forces are exerted to the stalk by rollers, said rollers also convey the stalk in the longitudinal direction of the stalk.

15. Method according to claim 13 or 14, wherein the position of the rollers is detected for controlling the radial forces exerted to the stalk to bring the stalk in a straight line.