WO2024089444A1

WO2024089444A1 - Spraying system

Info

Publication number: WO2024089444A1
Application number: PCT/HU2022/050076
Authority: WO
Inventors: István GŐZSE
Original assignee: IVÁNYI, Richárd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2024-05-02

Abstract

The invention relates to a spraying system comprising a spraying bar with at least one segmented section having in the direction towards an outer end of the spraying bar: - a first self-orienting joint (21 ) interconnecting a preceding bar segment (30) and a first bar segment (31 ), the first self-orienting joint (21 ) defining a self-oriented relative orientation for the interconnected preceding and first bar segments (30, 31 ), and - a second self-orienting joint (22) interconnecting the first bar segment (31 ) and a second bar segment (32), the second self-orienting joint (22) defining a self- oriented relative orientation for the interconnected first and second bar segments (31, 32), wherein one of said self-oriented relative orientations corresponds to the relative orientation of the respective interconnected bar segments in a folded bar segment arrangement of the spraying bar, and the other self-oriented relative orientation corresponds to the relative orientation of the respective interconnected bar segments in an extended bar segment arrangement of the spraying bar.

Description

SPRAYING SYSTEM

TECHNICAL FIELD

The invention generally relates to a spraying system, and in particular to agricultural spraying with a vehicle-mounted spraying equipment. Such spraying includes, for example but not by way of limitation, horticulture and ground maintenance spraying, as well as applying fluid or liquid to agricultural fields.

BACKGROUND ART

There is a continuous need to increase world food production due to population growth and higher consumer expectations. However, while population growth follows an exponential trend, productivity of agricultural areas can only be increased in smaller increments. This problem is further complicated by the fact that agricultural areas can no longer be increased significantly, and the climate is changing dramatically. Radically new technological solutions are therefore needed to increase agricultural productivity.

Spraying is a well-known method of applying a wide variety of bulk materials, primarily fluids, including e.g. liquids, powders, mixtures of liquids and powders, also in a fluid propellant medium, etc. Such spray materials can be dispensed in air currents, under liquid pressure, by gravity flow, or with any other suitable discharge means. Spray application of bulk materials offers many potential advantages, including efficiency, uniformity of coverage and flexibility to adapt spraying equipment to various conditions unique to the objects being sprayed and their particular environments.

In the agricultural industry, agricultural fluids are commonly applied to fields for a variety of reasons. Agricultural fluids include, without limitation, fertilizers and growth regulators for nutrient management, pesticides and insecticides for crop pest management, as well as fungicides. Agricultural fluids are usually liquids, but mixtures of liquids and powders are also common.

Typically, systems for applying fluid to fields include a manifold, e.g., a boom, and a plurality of nozzle assemblies that receive the fluid from the manifold for applying to the field. In at least some known systems, the fluid is delivered to the manifold through an inlet located between opposed ends of the manifold. The fluid travels longitudinally through the manifold from the inlet toward the opposed ends. As the fluid flows towards the opposed ends, a portion of the fluid is directed out of the manifold towards the nozzle assemblies for application to the fields. In order to distribute the liquid products over the ground or over the top of cultivated vegetation in a uniform and optimal manner, the nozzles of the boom must all be aligned along a direction substantially parallel to the ground or to the top of cultivated vegetation and placed at a height which remains substantially constant during the entire sprinkling.

Notwithstanding its substantial advantages, this typical prior art agricultural spraying is generally a relatively inefficient process. Factors which contribute to such inefficiencies include the susceptibility of sprayed materials to wind drift, overspray and inaccurate placement on the sprayer. Irregularities in terrain and nonuniform plantings also contribute to the inconsistent and inefficient application of agricultural spray materials. In addition to the inefficiencies associated with misdirected agricultural spray materials, overspray and spray drift can create significant problems if the materials are inadvertently applied to adjoining areas for which they were not intended. Such misapplication of agricultural spray materials can result in crop damage, injury to livestock and to insect pollinators such as honeybees, contamination of environmentally-sensitive areas and unnecessary human exposure to toxic materials.

The problems associated with the misapplication of agricultural spray materials are even larger in the case of currently available larger spraying equipment covering wider swaths. The main drawback of these solutions of known type is tied to the fact that, due to the large straight dimensions of the lateral arms of the sprinkling bar, irregularities in terrain and nonuniform plantings result in the above mentioned inconsistent and inefficient spraying. It is necessary that the arms of the known sprinkling bars are made with strong, heavy and therefore costly materials. Furthermore, the weight of such known structures increases more than proportionally with the width, so their application is not practical beyond a certain with, e.g. 50 m. In the same manner, in order to support such arms of the sprinkling bar, the support frame of the apparatus must be made stronger, increasing the overall cost of making the apparatus of known type. In addition, such a stronger support frame considerably increases the weight of the sprinkling apparatus. A greater weight of the sprinkling apparatus translates into a greater compaction of the cultivated ground upon passage of the sprinkling apparatus itself, decreasing the productive yield of the cultivation. A number of prior art systems are known, in which a wide coverage is achieved and still some above-mentioned disadvantages are solved by spraying structures carried by unmanned aerial vehicles, drones, unmanned aerial carriers or propeller units. The unmanned aerial carrier is provided with at least one rotary propeller around a vertical axis in order to maintain the support frame suspended. The propeller is rotated usually by a corresponding electric motor, to which power is supplied by a battery or from a central supply via electric conduits.

LIS2018133741 A1 discloses a ground-based heavy payload ground vehicle, trailer, or fixed ground station to deliver agriculture chemical, power and control signals to a propeller lift, hinged boom truss module using unmanned aerial vehicles technology to unload and suspend multiple boom truss modules, extending out to cover a large spray area. Drawbacks of this known system is that the hinged boom truss module still necessitates a rather reinforced and therefore relatively heavy structure, the structure is not sufficiently segmented and has therefore large overall dimensions even in a folded state, and that the unfolding and folding processes are not facilitated by the hinges.

Other types of spraying or sprinkling apparatuses for distributing farming products are also generally available on the market, such as farming machinery which is carried, towed or self-propelled, such as pulverizers, which are employed for distributing one or more liquid products over cultivations. Such apparatuses are conventionally provided with at least one support frame provided with wheels for its movement on the ground and at least one sprinkling or spraying bar for distributing liquid products that is mechanically constrained, at one end thereof, to the support frame. The sprinkling bar of the apparatus of known type is, during the distribution of the liquid products over the ground, arranged parallel to the ground and transverse with respect to the advancement direction of the apparatus. The sprinkling bar normally carries, mounted thereon, a plurality of dispensing nozzles directed towards the ground and hydraulically connected to a tank housed in the central body and containing the liquid product to be distributed. The known apparatus also provides for a pump mounted on the support frame, hydraulically connected to the tank and to the nozzles of the sprinkling bar. For example, EP3653051 A1 discloses such a sprinkling apparatus.

In operation, a pump mounted on the support frame of the known apparatus, and in particular of the farming machinery, suctions the liquid product from the tank and conveys it under pressure to the dispensing nozzles in order to sprinkle it on the cultivations during the advancement of the farming machinery. In operation, lateral arms of the sprinkling bar of the sprinkling apparatus of known type are movable between an open position, in which they are extended transversely to the advancement direction of the farming machinery in order to allow the nozzles to distribute the liquid product over the cultivated ground, and a closed position, in which the arms are folded along the sides of the farming machinery.

Furthermore, the sprinkling apparatus disclosed in EP3653051 A1 comprises a support frame, a sprinkling bar provided with a plurality of distribution nozzles, associated with the support frame and movable between an extended position, in which it projects laterally with respect to the support frame and a retracted position, in which it is placed in proximity to the support frame, means for feeding farming products associated with the support frame placed in hydraulic connection with the plurality of nozzles and at least one drone fixed to the sprinkling bar in order to aerially support it. Although this known sprinkling bar has a lighter structure, the structure is still not sufficiently segmented and has therefore large overall dimensions even in a folded state, and the unfolding and folding processes are not facilitated by the structure.

Self-orienting solutions for joints are utilized e.g. in vehicle or other doors exhibiting auto-returning or hinge arrester properties, like those disclosed in e.g. US 2002/0066160 A1 and US 2004/0020014 A1 . However, there is no teaching in the prior art to utilize such properties for facilitating unfolding and folding processes of lengthy structures, especially in connection with spraying.

Thus, there is a need for a spraying system which has a lighter structure, enables relatively small overall dimensions in a folded arrangement, and in which the unfolding and folding processes are facilitated by the structure itself.

DISCLOSURE OF THE INVENTION

It is a main object of the invention to overcome the drawbacks of prior art solutions as much as possible, and to provide a spraying system with advanced features that is inexpensive and easy to implement with few components and which is adaptable to most existing sprayer vehicles. Further objects of the invention are to enable a spraying system with a lighter structure and with a segmentation enabling smaller overall dimensions in a folded arrangement. It is a still further object of the invention to provide a structure in which the unfolding and folding processes are facilitated by the structure itself, by means of self-orienting effects present in joints of the structure.

A further object is to provide a spraying bar structure which

- can be controlled to remain at a constant elevation with respect to the ground or to the top of cultivated vegetation to be treated, resulting in a reduced drifting of the spraying material and also enabling even pesticide spraying,

- provides a wider coverage than existing structures, thereby resulting a faster spraying process,

- enables spraying also in the case of soil conditions presently prohibiting spraying with land vehicles,

- is made of light and inexpensive materials,

- is simple to use,

- is reliable even for long time periods,

- allows reducing, to a minimum, the compaction of the ground in order to maximize the production efficiency of cultivations of the ground, and

- preferably facilitating further functions, such as camera scanning and diagnosing functionalities, also enabling less overall and targeted delivery of the spraying materials, e.g. pesticides.

The above objects have been achieved by the spraying system according to claim 1 . Preferred embodiments of the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Technical characteristics of exemplary preferred embodiments of the invention will be discussed in the following detailed description with reference to the enclosed drawings, where:

Fig. 1 is a schematic view of a preferred embodiment of a spraying system also comprising a carrying land vehicle, and with a spraying bar being in an extended bar segment arrangement,

Fig. 2 is a schematic view of a segmented section of the spraying bar of Fig. 1 ,

Figs. 3 and 4 are schematic views of an embodiment of the segmented section with bar segments in two different relative orientations,

Fig. 5 is a schematic view of a further embodiment of the segmented section, Figs. 6-18 are schematic views of phases of folding the spraying bar from an extended bar segment arrangement into a folded bar segment arrangement,

Figs. 19 and 20 are schematic views of an embodiment of a self-orienting joint, formed as a ball joint, with bar segments in two different relative orientations,

Fig. 21 is an exploded view of the ball joint of Figs. 19 and 20,

Fig. 22 is a cross sectional view of the ball joint of Figs. 19 and 20,

Figs. 23 and 24 are schematic views of an embodiment of a self-orienting joint, formed as a universal joint, more particularly as a cardan joint,

Figs. 25 and 26 are schematic views of the cardan joint of Figs. 23 and 24 with bar segments in two different relative orientations,

Fig. 27 is an exploded view of the cardan joint of Figs. 23 and 24,

Fig. 28 is a schematic view of a cardan cross of the cardan joint of Figs. 23 and 24, and

Fig. 29 is a cross sectional view of the cardan joint of Figs. 23 and 24.

MODES FOR CARRYING OUT THE INVENTION

In the context of the present application, a new approach is presented for agricultural spraying. Plant protection concerns both the diagnosis of problems in plant development and the necessary intervention. The inventive spraying system preferably comprises a camera system capable of taking high-resolution images of the vegetation to facilitate diagnosis. The spraying system allows laying a long spraying bar above the field, which is supported by lifting thrust generating units above the vegetation.

The inventive spraying system preferably comprises the following main parts: the spraying bar, a base unit with a support structure, a tank and associated auxiliary equipment (such as duct, spraying nozzles, pump, central computer as a control unit) and a transporting vehicle.

Fig. 1 is a schematic view of a preferred embodiment of a spraying system comprising a carrying land vehicle 10, a base unit 11 having a support structure 12 and a tank 13 adapted to contain a fluid to be sprayed. The land vehicle 10 preferably carries or tows the base unit 11 , but any sort of other types of carrying modes or carrying vehicles are possible. The support structure 12 may be formed as a frame mounted onto the land vehicle 10. Two spraying bars 14 are attached to the support structure 12 with their inner ends, wherein outer ends of the spraying bars 14 are free. Preferably, the vertical position of the support structure 12 is adjustable according to the required vertical distance from the ground or from the actual top level of the cultivated vegetation, wherein the spraying bars 14 preferably follow that adjusted vertical distance. Each spraying bar 14 comprises bar segments interconnected by joints. The spraying bars 14 are depicted here in their extended bar segment arrangement, but those can be folded into a folded bar segment arrangement as detailed below. The support structure 12 preferably also comprises a holding structure 15 for accommodating the spraying bars 14 in their folded bar segment arrangement.

The spraying system does not necessarily have two spraying bars 14, but any suitable number of the spraying bars 14 attached to the support structure 12 is conceivable. The spraying bars 14 are preferably straight in top view in the extended bar segment arrangement, and therefore always maintain a crosswise arrangement with respect to the driving direction of the carrying land vehicle 10.

The inventive spraying system also comprises nozzles known per se (not shown) carried by said spraying bar 14, and a duct known perse (not shown) being associated with the spraying bar 14 and interconnecting the tank 13 and the spraying nozzles. The duct is preferably formed at least partly within the spraying bar 14, e.g. it can be an internal channel along the spraying bar segments also crossing or circumventing the interconnecting joints between bar segments, but it can also be attached externally to the spraying bar 14.

The inventive spraying system also comprises thrust generating units 16 attached to the spraying bar 14. The thrust generating units 16 can be any sort of device that generate thrust (rocket, jet engine, etc.) but preferably these are rotary propeller units with at least one rotary propeller as shown in the Figs. The purpose of the thrust generating units 16 is to maintain the spraying bar 14 suspended above the ground or the top of cultivated vegetation during spraying, as well as to carry out the unfolding and folding process. To this end, the spraying system preferably comprises a control unit for a plurality of thrust generating unit 16, which control unit is adapted to control the thrust generating units 16 to sequentially unfold segmented sections of the spraying bar 14 from the folded bar segment arrangement into the extended bar segment arrangement, and to sequentially fold the segmented sections from the extended bar segment arrangement into the folded bar segment arrangement. As it will be shown later, these processes are facilitated by the special joints used in the spraying system. Electric conduits for electrical power supply and for data transmission may be carried by or can be embedded into the spraying bar 14 and the thrust generating units 16 may be controlled by the control unit via the electric conduits. Thanks to this solution, the thrust generators do not have to lift heavy batteries, as is a basic requirement for a multirotor unmanned aircraft. The system thus has lower power requirements and longer operating times. The thrust generating units 16 can also be controlled to follow any unevenness of the soil surface.

Fig. 2 is a schematic view of a segmented section of the spraying bar depicted in Fig. 1.

The thrust generating unit 16 preferably comprises a crossbar 17 attached crosswise to the respective second bar segment 32, and two motor-driven propellers 18 attached to the crossbar 17 at respective ends thereof. The motor-driven propellers 18 are preferably tiltable around an axis defined by the crossbar, as denoted by an arrow in Fig. 2. Tiltability has the advantage that the motor-driven propellers 18 can easily continuously maintain a horizontal plane of rotation, whereby the control of the motor- driven propellers 18 and of the unfolding and folding processes can be simplified. Furthermore, following any unevenness of the soil surface, e.g. of hillsides is considerably facilitated by this feature. The propellers 18 are preferably driven by electric motors, e.g. brushless DC motors. Each pair of lifting propellers 18 is preferably equipped with an appropriate sensor system to determine their spatial position and orientation, and an on-board computer which collects sensor data, runs a stabilisation controller and preferably communicates with other pairs of propellers and the control unit being a central computer.

Thus, the spraying bar 14 comprises at least one segmented section having in the direction towards the outer end of the spraying bar 14:

- a first self-orienting joint 21 interconnecting a preceding bar segment 30 and a first bar segment 31 , the first self-orienting joint 21 defining a self-oriented relative orientation for the interconnected preceding and first bar segments 30, 31 , and

- a second self-orienting joint 22 interconnecting the first bar segment 31 and a second bar segment 32, the second self-orienting joint 22 defining a selforiented relative orientation for the interconnected first and second bar segments 31 , 32. The term ‘self-orienting joint’ denotes a joint which is capable of orienting itself automatically into a certain relative orientation of the interconnected parts, in the given case, interconnected bar segments. The self-orienting effect, i.e. forces and/or torques acting to bring the joint automatically into the self-oriented (or in other words: selfaligned) relative orientation can be present in the entire movement range of the joint, or in some sub-ranges or only in one sub-range thereof, e.g. within a solid angle of the entire movement range of a three degree-of-freedom joint. In the latter case, the selforienting effect is present only if the relative orientation of the interconnected parts is within the solid angle. The magnitude of such self-orienting forces and/or torques can be uniform within the relative orientation range, e.g. within the solid angle, or can vary therein. The self-orienting joint is moveable from the self-oriented relative orientation, e.g. away from that orientation or even outside of the relative orientation range or outside of the solid angle of self-orientation, by applying a sufficiently large force and/or torque, i.e. a force and/or torque larger than that effected by the joint urging itself towards the self-oriented relative orientation.

Thus, self-orienting joints are joints that allow free movement generally like a general ball or other joint, but with a certain predetermined degree of stiffness or a stability over a range to maintain a certain predetermined position.

According to the invention, one of said self-oriented relative orientations corresponds to the relative orientation of the respective interconnected bar segments in the folded bar segment arrangement, and the other self-oriented relative orientation corresponds to the relative orientation of the respective interconnected bar segments in the extended bar segment arrangement. The considerable advantage of this structure is that at certain phases of the unfolding and folding effected successively on the segmented sections, in each segmented section one of the two joints is in its selforiented relative orientation, and therefore exhibits some extent of rigidity, thereby resulting a predetermined behaviour during the unfolding/folding process. The other joint is freer to move at that phase, so even in the case of the relatively low unfolding/folding forces/torques exertable by means of the thrust generating units 16 result in a controlled unfolding/folding process, the free joint defines the axle of rotation or turning of the segmented section, and it is not necessary to include additional actuators, i.e. to increase the number of thrust generators. The spraying bar 14 can have any number of segmented sections, preferably in a successive arrangement, in which a preceding bar segment 30 of a given segmented section constitutes the second bar segment 32 of the previous segmented section. In this way a spraying bar 14 can be achieved, which consists of rigid rods connected by special joints held above the field by thrust generators. At the bottom of the spraying bar 14 are the nozzles that perform the spraying function. This is also where cameras for monitoring can be located. Such scanning cameras can be distributed along the length of the spraying bar 14, which scanning cameras face downwards in the extended bar segment arrangement.

The control unit may also process the images from the cameras, calculate the amounts of spray required, and control the entire spraying process. The control unit may also save data via the Internet and may utilize data from previous surveys, if necessary. An interface to an operator may also be provided by the control unit.

As depicted in Fig. 2, the first bar segment 31 is preferably shorter than the second bar segment 32, the self-oriented relative orientation defined by the first self-orienting joint 21 coincides with the relative orientation of the interconnected preceding and first bar segments 30, 31 in the folded bar segment arrangement, and the self-oriented relative orientation defined by the second self-orienting joint 22 coincides with the relative orientation of the interconnected first and second bar segments 31 , 32 in the extended bar segment arrangement. In this way an easily manageable folding/unfolding process can be achieved. To this end, even more preferably, one thrust generating unit 16 is attached to each segmented section, wherein the thrust generating unit 16 is attached to the second bar segment 32, and said attachment is closer to an outer end of the second bar segment 32 than to its end to which the second self-orienting joint 22 is attached.

The above arrangement also has the following advantages:

- By positioning the thrust generating unit 16 at the end of the second bar segment 32, the spatial position error of the segmented section due to the navigation error of the rotor pair is minimized.

- No other actuators are needed for folding and unfolding the structure.

- As the direction of the rigid range of the joints can be selected, there is a high degree of freedom for organize folding. The structure can be folded over each other or into several columns or a combination of the two, so that it takes up less space when folded and optimum use can be made of the available space. The spraying bar 14 can be - at least in top view - straight in the extended bar segment arrangement, and at least a part of the spraying bar 14 can have a serpentine shape in the folded bar segment arrangement. Rotor pairs can also be folded offset from each other.

Figs. 3 and 4 are schematic views of an embodiment of the segmented section with bar segments in two different relative orientations.

Figs. 3 and 4 both depict with dashed lines the solid angles in which the self-orientation properties are present for the respective joints. The first self-orienting joint 21 provides self-orientation within a circular solid angle 41 , the centre line of which is preferably perpendicular to the preceding bar segment 30. The depicted solid angle 41 shows the movement range for the first bar segment 31 , in which the self-orienting effect is exerted on the first bar segment 31. Similarly, the second self-orienting joint 22 provides self-orientation within a circular solid angle 42, which represents the selforienting effect for the second bar segment 32. Fig. 3 corresponds to the extended bar segment arrangement, where the first self-orienting joint 21 is not in the self-orientation range and freely moves, as the longitudinal axis of the first bar segment 31 is outside of the solid angle 41 . The second self-orienting joint 22 is, however, in its self-oriented relative orientation, as a central axis of the second bar segment 32 is within the solid angle 42. Fig. 4 corresponds to the folded bar segment arrangement, where the situation is opposite; the first self-orienting joint is in its self-oriented relative orientation, as the first bar segment 31 has a central axis within the solid angle 41 , and the second self-orienting joint 22 is outside of its self-orientation range, as the second bar segment 32 has a central axis outside of the solid angle 42.

As in the extended bar segment arrangement each first self-orienting joint 21 provides a non-self-oriented, i.e. flexibly moveable interconnection, less power is needed for the thrust generating units 16 to shape the structure to follow any unevenness of the soil surface with the spraying bar 14. This is even more so if the first self-orienting joints 21 are outside of their respective the self-orientation ranges in the extended bar segment arrangement, as depicted e.g. in Fig. 3. A straight top view is preferably continuously maintained for the spraying bar 14 in the extended bar segment arrangement. Each second self-orienting joint 22 provides, however, a straight, self- oriented interconnection in the extended bar segment arrangement, so there is one flexibly moveable interconnection for each thrust generating unit 16 in a segmented section, which allows an easier overall control of the thrust generating units 16.

In the preferred embodiment depicted in Figs. 3 and 4 circular solid angles 41 , 42 are shown. However, a non-circular solid angle 51 or angles are also possible, as depicted e.g. in Fig. 5.

The directionally stable joints are to an extent rigid in one direction and behave like a free movement joint in other directions. The joints can preferably bend more than 90°.

Figs. 6-18 are schematic views of phases of folding the spraying bar 14 from an extended bar segment arrangement into a folded bar segment arrangement,

Some of the Figs. 6-18 also show the solid angles with dashed lines, in which the selforienting effect is present. The folding process is preferably carried out by means of the thrust generating units 16 and is facilitated with the above detailed self-orienting properties of the joints.

In Fig. 6 the holding structure 15 has a support member in an upright position, and the segmented section closest to the support structure 12 is folded onto the support member as depicted in Fig. 7. Fig 8 shows the next phase, during which the second segmented section is tilted upwards, during which the respective second self-orienting joint 22 remains in its self-oriented relative orientation, coinciding with the straight arrangement. During this upright tilting, the respective segmented section can be moved as it was a one-piece bar, resulting in a more controlled folding process and an easier control for the thrust generating units 16. During the upright tiling as depicted in Fig. 8 the segmented section reaches a certain angle, in which the respective first selforienting joint 21 gets within its respective solid angle 41 , where the first bar segment 31 is forced in its upright orientation and in turn the second self-orienting joint 22 is turned out of its self-oriented state. This allows to move the second segmented section as depicted in the transition in Figs. 9 and 10, and can be folded in parallel with the first folding and can be put onto the upright support member of the holding structure 15. These steps can be continued as depicted in Fig. 11 until which the upright support member of the holding structure 15 is fully packed with a first column of folded segmented sections. Thereafter, the packed part of the structure can be tilted as depicted in Fig. 12 and folding a second part of the spraying bar 14 can be started in the same way, onto a second support member of the holding structure 15, now flipped into an upright position. The folding process as depicted in Figs. 14 and 15 can be continued similarly by packing the segmented sections downwards onto the upright support member. After this second packing process is completed as depicted in Fig. 16, the second packed part can also be tiled as depicted in Fig. 17 and a further lateral displacement also be effected as shown in Fig. 18 to achieve the most possible packed arrangement. During this process, the propellers 18 preferably used as thrust generating units 16, if necessary, rotate to move out of the way of the bar segments.

All the above movements of parts of the spraying bar 14 can be preferably effected by means of controlling the thrust generating units, resulting in a simple spraying bar structure. Unfolding can be carried out in an opposite process.

Figs. 19 and 20 are schematic views of an embodiment of a self-orienting joint, formed as a ball joint 100, with bar segments 31 , 32 in two different relative orientations. Fig. 21 is an exploded view of the ball joint 100.

The exploded view of the ball joint 100 in Fig. 21 shows a spherical element 101 having a seat surface 102. A rubber tube 103 is extended over the spherical element 101 and its both ends are held firmly. The flexibility of the pre-tensioned rubber tube 103 allows some rotational movements between the bar segments 31 , 32, which is sufficient for the axial rotation necessary for the folding and unfolding as depicted in Figs. 6 to 18. A first end of the rubber tube 103 is held firmly in the end of bar segment 31 , while the other end is held firmly by a retaining ring 104. This pre-tension holds the two halves of the joint in place. Free movement is ensured by the low stiffness of the rubber tube 103, so that the excess elongation during flexion has only a minimal effect, but the pretensioning provides sufficient holding force.

A latch, a shaft or a pin 105 is pressed by a coil spring 106 onto the spherical element 101 and the self-orienting effect is ensured by the seat surface 102 and by the pressengagement ensured by the coil spring 106. The seat surface 102 can be formed according to the required self-orienting properties.

Fig. 22 is a cross sectional view of the ball joint 100 of Figs. 19 and 20. In this cross sectional view the pin 105 is pressed by the coil spring 106 onto a spherical surface part of the spherical element 101 , i.e. not on the area defined by the seat surface 102, so the ball joint 100 is not in its self-oriented state.

Preferably, the pressing end of the pin 105 can have a shaped surface, e.g. can have a dent or a protrusion with a predetermined form, or can have a structured surface, mating with a complementary seat surface 102. In this way, some extent of rotational locking can also be ensured in the self-oriented state.

Figs. 23 and 24 are schematic views of an embodiment of a self-orienting joint, formed as a universal joint, more particularly as a cardan joint 200. Figs. 25 and 26 are schematic views of the cardan joint 200 of Figs. 23 and 24 with bar segments in two different relative orientations, while Fig. 27 is an exploded view of the cardan joint 200.

The cardan joint 200 has a first cardan fork 201 and a first pin 202 which is pressed onto a cardan cross 203. The cardan cross 203 has a cross member surrounded by two circular components, acting as pin guides, which are arranged along planes being perpendicular to each other. The joint also has a second cardan fork 204 which is axially turnable by means of bearings 205. So, one end of the universal joint is free to rotate about its axis; without this the joint would not exhibit three-degree of freedom rotational properties. A second pin 206 is also pressed onto the cardan cross 203. The pressing of the first and second pins 202 and 206 is effected by a coil spring 209 and the pressing force is transmitted to the first pin 202 via a cable, preferably a bowden cable 210.

Preferably, the pin 206 has a structure also having protrusions 208 which can engage into respective recesses 207 formed in the second cardan fork 204. In this way, in a self-oriented relative orientation, even the rotational movement can be blocked to some extent. Thus, rotation can be prevented in the same way as for the ball joint 100 when the joint is in the correct position.

Fig. 28 is a schematic view of a cardan cross 203 of the cardan joint 200 of Figs. 23 and 24. The cardan cross 203 has a first flattened seat surface 211 and a second flattened seat surface 212 for the first and second pins 202, 206, respectively, on which the first and second pins 202, 206 sit when the joint is in the correct, i.e. self-oriented position. As in the case of the ball joint 100, the first and second seat surfaces 211 , 212 can be formed/shaped according to the required self-orienting properties. Fig. 29 is a cross sectional view of the cardan joint 200 of Figs. 23 and 24 showing especially the structure with the bowden cable 210 transmitting to the first pin 202 the pressing force effected by the coil spring 209. The pins are only activated when each one is positioned over the respective seat surface 211 , 212 to ensure that movement is stable in the range of one self-aligned relative orientation only. The design of the pins and of the preloading spring allow to determine stiffness and the solid angle of the joint’s self-orienting, i.e. directional stability properties.

Thus, the operation of preferred embodiments of the joints is based on the fact that the joint is locked in a given position by a combined action of one or more latches, pins or shafts which are held in place by one or more springs. The pins are pressed by a spring force, so that the joint is forced to a given position within a given angular range.

The inventive system provides in a single structure also for the collection of important data for precision crop protection and optimal application of intervention materials. To plan a crop protection intervention, the scanning cameras may capture images above the vegetation 50x faster than today’s best unmanned system, with up to 10x higher resolution. During the intervention, the inventive system can spray at a locally differentiated, optimized rate up to 10x faster than today’s commonly used spraying systems.

In a typical operating mode, the spraying bar 14 is extended by means of the individual lifting thrust generators, which are actuated to maintain both the height and the lateral position of the spraying bar 14. The possible length of the spraying bar can be up to 200 metres, for example. It can pass over the cropland as a first step and can take pictures of it. The spraying bar 14 can carry a plurality of cameras close to the vegetation, so the resolution of the obtained images is extremely good. The resulting image data provides opportunity to diagnose and to detect problems. The images can be evaluated conventionally or even automatically by image-processing artificial intelligence, which can be more accurate than human diagnosis in some cases, as it is already better than human diagnosis in some areas of medicine, such as breast cancer or melanoma detection.

The speed at which it is possible to scan is 10 to 15 km per hour, so with a 200 m long spraying bar 14 an area of about 40 hectares can be surveyed in 10 minutes, so its speed and resolution are orders of magnitude better than those of existing systems. The result of the scan is that e.g. it becomes possible to know exactly where and how much pesticide needs to be applied. The extended spraying bar 14 can be passed over the field in a second phase, and apply the pesticide only where it is needed, and this can also be done by completing 40 hectares in 10 minutes. The inventive solution complies with Ell directives (Directive on Sustainable Use of Plant Protection) and fits into the general objects of precision farming systems.

An important benefit of a crop protection system using the inventive system is that it significantly reduces trample and soil compaction damage. In case of 200 m long spraying bars 14 on both vehicle side, cultivation roads can be located at 400 m intervals, in contrast to the currently usual 18-24 m intervals. Given that the spraying bar 14 can follow any surface, more accurate spraying can be achieved on uneven surfaces. One major disadvantage of a rigid spraying frame is that even with small curvatures of the ground or of the top of cultivated vegetation there can be significant differences in spreading height, and this becomes more significant as the frame size increases. The evenness of the spread has a direct impact on production and should therefore always be achieved as much as possible. The proposed system can follow the unevenness of the surface thanks to its segmented structure, thus producing a more uniform quality of the crop.

Another benefit of the invention is that spraying time can be significantly reduced, which saves manpower and machinery resources. At the same cultivation speed, a 200 m spray width sprays many times as much area as with conventional techniques. This results in labour savings, proportionally less energy consumption and less environmental damage.

A further advantage is that there is no need to wait for the soil to dry. The presently used heavy structures cannot be applied on wet soil, as due to their heavy weight the soil structure would be destroyed, damage could be caused in the cultivated vegetation due to slipping and the carrying vehicle could stuck in the mud. At present one has to wait until the soil has dried, which would lose valuable time for farmers to control pests and cause serious financial damage, especially critical if there is only a short drying period between two rainy seasons. By using the inventive spaying structure, once the vegetation has dried, the spray can be applied. Furthermore, if e.g. the width of the field is less than twice of the length of the spraying bar 14, the proposed solution can spray from the service roads next to the field, thus eliminating this problem. The inventive system may also comprise inertial measurement units (IMU). The inertial measurement units measure the acceleration and angular velocity of each thrust generator pair, e.g. propeller pair. These data are essential for determining the spatial orientation, which, when supplemented with position data, can be used to calculate the most important data required for control. Ultrasonic distance sensors, already proven and widely used in the automotive industry, are an excellent way to detect height above vegetation. The spatial position of each pair of thrust generators is essential to ensure that the spray is applied in the correct distribution and that the relative position of the connected pairs of thrust generators is kept stable. This task can be solved e.g. with low-cost real-time kinematic (RTK) Global Navigation Satellite Systems (GNSS) modules. RTK GNSS modules work in a similar way to the well-known GPS receivers, but allow a much more accurate positioning.

The spraying bar 14 itself, together with the thrust generators, is not a rigid structure, so its stability must be ensured by a control algorithm. Data from the sensors on each pair of thrust generators can be collected by an on-board computer and shared with the other pairs of thrust generators. Based on this data set, each pair of thrust generators may calculate the speed at which its own thrust generators must rotate in order to maintain the position of the whole assembly. The control algorithm may be able to keep the system stable despite the differences between each pair of thrust generators, so robustness is ensured. A key safety issue can be that the control algorithm for a pair of thrust generators can detect when a pair of thrust generators has failed and then switch itself off. At the same time, each pair of thrust generators may monitor the other pairs of thrust generators, so that if one fails and does not turn itself off, the others may, by majority vote, turn off the failing pair of thrust generators. After the shutdown, it must modify its own operation so that the entire spraying bar 14 remains stable.

Control of individual thrust generating units 16 may be carried out exclusively centrally with the control unit, or exclusively with their local on-board computers, or in a mixed manner.

Of course, the self-orienting joints 21 , 22 can be formed with other types of joints, hinges or connections as well. The joints can have a three-dimensional degree of rotary freedom or can have less degree of freedom, as required by the given application.

Claims

1 . A spraying system comprising

- a base unit (11 ) having a support structure (12) and a tank (13) adapted to contain a fluid to be sprayed,

- a spraying bar (14) having an inner end attached to said support structure (12) and an outer end, the spraying bar (14) comprising bar segments (30, 31 , 32) interconnected by joints (21 , 22), wherein the spraying bar (14) has an extended bar segment arrangement and a folded bar segment arrangement,

- spraying nozzles carried by said spraying bar (14),

- a duct being associated with the spraying bar (14) and interconnecting said tank (13) and said spraying nozzles, and

- thrust generating units (16) attached to the spraying bar (14), characterized in that the spraying bar (14) comprises at least one segmented section having in the direction towards the outer end of the spraying bar (14):

- a first self-orienting joint (21 ) interconnecting a preceding bar segment (30) and a first bar segment (31 ), the first self-orienting joint (21 ) defining a self-oriented relative orientation for the interconnected preceding and first bar segments (30, 31 ), and

- a second self-orienting joint (22) interconnecting the first bar segment (31 ) and a second bar segment (32), the second self-orienting joint (22) defining a selforiented relative orientation for the interconnected first and second bar segments (31 , 32), wherein one of said self-oriented relative orientations corresponds to the relative orientation of the respective interconnected bar segments in the folded bar segment arrangement, and the other self-oriented relative orientation corresponds to the relative orientation of the respective interconnected bar segments in the extended bar segment arrangement.

2. The spraying system according to claim 1 , characterized in that the first bar segment (31 ) is shorter than the second bar segment (32), the self-oriented relative orientation defined by the first self-orienting joint (21 ) coincides with the relative orientation of the interconnected preceding and first bar segments (30, 31 ) in the folded bar segment arrangement, and the self-oriented relative orientation defined by the second self- orienting joint (22) coincides with the relative orientation of the interconnected first and second bar segments (31 , 32) in the extended bar segment arrangement.

3. The spraying system according to claim 2, characterized in that one thrust generating unit (16) is attached to each segmented section, wherein the thrust generating unit (16) is attached to the second bar segment (32), and said attachment is closer to an outer end of the second bar segment (32) than to its end to which the second self-orienting joint (22) is attached.

4. The spraying system according to claim 3, characterized in that the spraying bar (14) is straight in top view in the extended bar segment arrangement, and at least a part of the spraying bar (14) has a serpentine shape in the folded bar segment arrangement.

5. The spraying system according to claim 4, characterized in that the support structure (12) comprises a holding structure (15) for accommodating the spraying bar (14) in the folded bar segment arrangement.

6. The spraying system according to claim 5, characterized by comprising a control unit and a plurality of segmented sections each with a corresponding thrust generating unit (16), wherein the control unit is adapted to control the thrust generating units (16) to sequentially unfold the segmented sections from the folded bar segment arrangement into the extended bar segment arrangement, and to sequentially fold the segmented sections from the extended bar segment arrangement into the folded bar segment arrangement.

7. The spraying system according to claim 6, characterized by comprising electric conduits carried by the spraying bar (14), wherein the thrust generating units (16) are controlled by the control unit via the electric conduits.

8. The spraying system according to claim 1 , characterized in that the duct is formed at least partly within the spraying bar (14), or is attached to the spraying bar (14).

9. The spraying system according to claim 1 , characterized in that the thrust generating unit (16) comprises a crossbar (17) attached crosswise to the respective bar segment (32), and two motor-driven propellers (18) attached to the crossbar (17) at respective ends thereof, wherein the motor-driven propellers (18) are tiltable around an axis defined by the crossbar.

10. The spraying system according to claim 1 , characterized by comprising a land vehicle (10) carrying or towing the base unit (11 ).

11. The spraying system according to claim 1 , characterized by comprising scanning cameras distributed along the length of the spraying bar (14), said scanning cameras facing downwards in the extended bar segment arrangement.

12. The spraying system according to claim 1 , characterized in that the first selforienting joint (21) provides self-orientation only within a circular solid angle (41 ) or a non-circular solid angle (51 ).

13. The spraying system according to claim 1 , characterized in that the second self- orienting joint (22) provides self-orientation only within a circular solid angle (42) or a non-circular solid angle.