AU2009202785B2 - Target vegetation treatment method and apparatus - Google Patents

Abstract

Apparatus (10) for treating target vegetation with herbicide, said apparatus being adapted to be mounted to a vehicle (27) and comprising vehicle sensing 5 means (25) for sensing the ground speed and direction of the vehicle (27), means (24) for recognizing vegetation to be treated, herbicide applying means (12) for applying herbicide to said vegetation and control means (26, 29, 42) designed and programmed to cause said herbicide applying means to apply herbicide to said vegetation when detected by said vegetation recognizing means and vary the timing 10 of application of herbicide and also the pressure and/or amount of applied herbicide on an infinitely variable basis in accordance with measurement of the ground speed and the direction of vehicle wherein said speed is also measured on an infinitely variable basis. rn cJ com C--1

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "TARGET VEGETATION TREATMENT METHOD AND APPARATUS" The following statement is a full description of this invention, including the best method of performing it known to us: 1 TARGET VEGETATION TREATMENT METHOD AND APPARATUS Technical Field 5 This invention relates to a target vegetation treatment method and apparatus and particularly but not exclusively to a method and apparatus for treating weeds or other vegetation with an herbicide. The method and apparatus are particularly applicable to the herbicide treatment of weeds or other vegetation growing in or adjacent to roadways or gutters but have other applications for vegetation treatment. 10 Background Art Weed control is a common problem in many situations in both rural and city locations. In the latter locations, weeds commonly grow alongside or in roadways or 15 gutters. The area most vulnerable to vegetation invasion is a continuous strip about 700mm to 800mm wide measured from the top of the kerb out onto the roadway. This strip is where many joints are provided and cracks can occur and these provide an ideal haven for opportunistic vegetation growth. Thus joins or cracks occur where the road surface merges with the roadside kerb and channel section and many different 20 kinds or surfaces can be encountered at this region. Joins or cracks also occur where the kerb and channel section meets with an adjoining footpath or grass verge and where modular sections of kerb and channels butt against each other. Gully pits, stormwater drains and driveways intersect with the kerb and channel section and also form joins or cracks. 25 Weeds also occur in cracks, fissures and holes in the road surface material itself and weeds in situations such as this can further damage the road surface by causing these cracks, fissures and holes in the road surface to enlarge and open up, often to the point where the surface material lifts and breaks away. This in turn increases the cost of maintenance, or if left unattended, actually decreases the asset 30 value. It is thought water penetrating beneath the road surface material is often the initial cause of these problems. Once it penetrates the surface it can break the bond between the sealed road surface and the underlying structure and the resulting hydrostatic pressure can actually cause the sealed surface to lift in a bubble like 2 manner. It is believed this is one of the major causes of potholes and the like and because the camber of the road tends to drain the water and air borne seeds to the sides of the road where there are many cracks and joins, this makes it an ideal place for weeds to germinate. 5 Additionally as weeds grow and expand they exert significant hydraulic forces beneath the road surface that can actually cause it to lift and fail. Initial damage caused by weeds establishing themselves in what might only be very small nooks and crannies at the time facilitate the entry of water with the result that both hydraulic and hydrostatic forces come into play, accelerating both the incidence and extent of 10 damage caused to the road surface. This is particularly evident on the sides of the road as the camber of the road is designed to encourage run-off toward the gutters and drains on the side of the road. Growth of vegetation such as weeds in the above regions is not only unsightly but also is a nuisance when weeds are permitted to spread and proliferate into 15 adjoining properties. In addition, weeds growing in drainage channelling can act as an impediment to water flow which has the potential to increase the risk of flooding. For many years, control of weeds encountered in the above situations has been carried out by manual spraying with two operators manning a vehicle carrying a bulk supply of herbicide with one person operating the vehicle and the other person walking 20 alongside the vehicle whilst carrying out manual spot spraying of any unwanted vegetation visible to the naked eye. This is obviously a labour intensive and time consuming process. In addition, this procedure is costly in terms of material use. Knapsack spraying is another common form at weed treatment that is still extensively practiced but has many disadvantages including operator fatigue as it is 25 usually extremely tiring to lug a full knapsack sprayer all day particularly if the roads are uneven or hilly. In addition, this type of equipment is not designed for accurate calibration and having to pressurise the tank with a hand pump leads to further inaccuracies and is very tiring. The operator furthermore commonly has to operate in an environment where he is usually exposed to a constant stream of passing traffic 30 which results in a safety risk as it is extremely difficult for operators to maintain concentration and a proper vigil all day when carrying out work of this type. Operators therefore have to be provided with regular breaks which in terms of daily work output further reduces productivity. Overall knapsack spraying is a very inefficient process. Other means of weed control involve the use of vehicles carrying herbicide 3 spraying equipment such as an agricultural type spray boom with several spray nozzles with such equipment being actuated manually. Whilst vehicles of this type can make the weed spraying process less labour intensive, herbicide usage is relatively high as it is usually necessary to spray an entire strip or area while travelling alongside 5 the road. This not only increases costs but can be environmentally damaging. For example, herbicide can enter drains along a roadway and thereafter enter waterways. In addition, spraying chemicals into water channels is on occasions considered to be unlawful and constitute "Unlawful Pollution". Whilst specific exemptions permit the use of herbicides registered for use in water catchment areas, blanket spraying a 10 continuous run of kerb and channel where the presence of vegetation is intermittent would almost certainly be considered an offence. Some herbicide spraying systems incorporate an optical recognition system such as cameras or infrared sensors with the aim of sensing the presence of weeds and actuating the spraying heads to spray herbicide when weeds are sensed. For 15 accuracy, vehicles carrying known technology of this type are required to travel relatively slowly in order to give the system time to capture and process the information then instruct the spraying heads to spray the weeds. This trade off involving the sacrifice of speed for accuracy is typical in systems of this type. Reference also may be made to prior art as described, for example, in US 20 Patent 5,606,821 which describes a smart weed recognition/classification system where there is also employed a plurality of nozzles or sprayheads wherein commands are sent to the nozzles by a microprocessor or PLC to spray herbicides or chemicals and control the rate, time and pattern of the spray as well as amount and type of chemical. The chemicals are sprayed from a moving platform and the microprocessor 25 or PLC also ensures that there is a weed recognition system which recognises target weeds. The microprocessor or PLC also has a sync input and a speed input. US Patent 5,507,115 also describes a microprocessor that controls operation of a solenoid which in automatic mode is controlled by a weed recognition sensor and the distance of the weed sensor from nozzles that apply herbicide to weeds in the direction 30 of travel of a vehicle carrying the microprocessor. The sensor distance, sensor speed and the solenoid turn-on delay are used by the microprocessor to release the herbicide from a spray nozzle at the moment when the nozzle passes over a weed. US Patent 7,081,611 refers to the use of a wheel encoder on a vehicle for application of herbicide to target vegetation of weeds where the wheel encoder senses 4 the speed of the vehicle and includes a sensor mounted to the rim of a flywheel which is adapted to generate a pulse every time it detects a tooth on the rim of the flywheel. Two wheel encoders may be used to identify when the vehicle is turning. There is also provided a microprocessor or controller which controls operation of solenoid controlled 5 valves upon detection of a target weed in combination with the distance pulses generated by the wheel encoder. Reference may be made to other prior art such as US Patent 5,842,307 and US Patent 5,222,324 which each describe an automatic spot weed sprayer which includes a photoelectric sensor for detection of weeds which sends a signal to a PLC which 10 triggers a spray nozzle for application of herbicide by a time delay based on the speed of the tractor. Reference also may be made to US Patents 5,793,035, 4,991,341 and 4,768,713 as well as International Publications W098/37977, W096/02817, W097/37372, W09748497, W098/11587, W098/19141, W096/12401, 15 W002/090908, W098/57539 and W094/02812 which all describe similar subject matter. However, the abovementioned prior art is deficient in that it does not allow for timing of application of herbicide through nozzles or sprayheads when a vehicle carrying these nozzles or sprayheads is accelerating or decelerating wherein it is 20 necessary to determine the amount or pressure of application of herbicide on an infinitely variable basis as well as determination of vehicle speed on an infinitely variable basis in combination with the direction of travel of the vehicle. Summary of the Invention 25 The present invention aims to provide a method and apparatus for treating vegetation with liquids and in particular aspect to a method and apparatus for herbicide treatment of weeds or other vegetation growing in or adjacent to a roadway surface which overcomes or alleviates one or more of the aforementioned 30 disadvantages of the prior art or which at least provides an effective alternative to the known herbicide treatment methods and apparatus. Whilst the present invention has particular application to the treatment of vegetation with herbicide, it may be applied to the treatment of vegetation with other liquids such as liquid fertilizers thus the term "herbicide" as used in the following description includes all liquids. The present 5 invention thus provides in one aspect although not necessarily the broadest aspect, apparatus for treating vegetation with herbicide, said apparatus being adapted to be mounted to a vehicle and comprising vehicle sensing means for sensing the ground speed and direction of the vehicle, means for recognizing vegetation to be treated, 5 herbicide applying means for applying herbicide to said vegetation and control means designed and programmed to cause said herbicide applying means to apply herbicide to said vegetation when detected by said vegetation recognizing means and vary the timing of applicationof herbicide and also the pressure and/or amount of applied herbicide on an infinitely variable basis in accordance with measurement 10 of the ground speed and direction of vehicle wherein said speed is also measured on an infinitely variable basis. Preferably operation of the herbicide applying means is controlled to ensure that herbicide is applied to the vegetation at substantially the same concentration per area irrespective of the vehicle speed. This will ensure high efficiency of herbicide 15 application, low wastage of herbicide and compliance with known statutes and regulations. The control means may be programmed to control the pressure and/or flow of the applied herbicide and/or the concentration of the applied herbicide for varying speeds of the vehicle. The herbicide applying means may include a pump and the 20 control means is suitably adapted to control operation of the pump. For example the control means may control the pressure/flow rate of the pump and therefore the pressure/flow rate of herbicide applied by the herbicide applying means. The control means may vary the operation of the pump depending upon the ground speed of the vehicle. Thus with an increase in ground speed, the control means may cause the 25 pump to deliver an increase flow or pressure of herbicide and vice versa. The control means is also suitably able to determine from the ground speed of the vehicle and the recognition/detection of vegetation by the vegetation recognition means, the time at which the herbicide applying means should commence operation and the duration of operation of the herbicide applying means to ensure that the detected 30 vegetation is treated. Preferably the herbicide to be applied by the herbicide applying means comprises one or more herbicide concentrates in a liquid carrier typically water. Preferably the herbicide concentrate is injected into an herbicide supply line through which herbicide and liquid carrier/s is/are applied to the herbicide applying means. Preferably liquid carrier storage means such as a tank are provided 6 for storing the liquid carrier such as water and herbicide storage means are provided for storing the herbicide concentrate. The herbicide supply line suitably communicates with the liquid storage means and the herbicide storage means. Preferably the control means is adapted to control the injection of the herbicide into 5 the supply line to control the concentration of herbicide applied to the herbicide applying means. Preferably the injection means includes a dosing pump or other suitable dosing device for metering and injecting the concentrated herbicide into the supply line under the control of the control means. Preferably one or more herbicides or other chemical concentrates can be injected into the supply line by 10 respective concentrate injection means associated with respective concentrate supplies. In the context used throughout this document the term 'chemical' should be taken to mean any product used for this purpose, irrespective of whether it a man made, or naturally occurring product, often referred to as an organic product. Preferably the vehicle speed sensing means senses the full range of speed of 15 the vehicle from zero speed when the vehicle is not moving. The speed sensing means further comprises a direction sensing means to sense the direction of movement of the vehicle so that the herbicide is not necessarily applied upon reversing movement of the vehicle. In a particularly preferred form, the speed sensing means or speed sensor 20 comprises a toothed wheel fixed for rotation with a part of the vehicle that accurately reflects both the rate and direction of travel. Preferably a pair of sensors are associated with the toothed wheel to detect respective teeth of the wheel as they move past each sensor upon rotation of the wheel. Each sensor preferably comprises a variable reluctance sensor to sense when a tooth of the wheel is in 25 proximity to the sensor. Detection of the proximity of respective teeth provides a pulse signal which is supplied to the controller and which is indicative of the rotational speed of the wheel and thus the ground speed of the vehicle. The faster the vehicle travels, the faster the teeth pass by the sensors. This in turn speeds up the signal impulses to the controller, which can mathematically calculate the speed of the 30 vehicle with a high degree of accuracy based on the frequency and time interval of the impulses. In a particularly preferred form, the two sensors are positioned at spaced apart positions relative to the toothed wheel or sprocket whereby each time a tooth of the wheel or sprocket passes a sensor a pulse signal is generated. The positioning 7 of the two sensors and the distance between them enables the speed sensor to determine the direction of travel. The sensors are positioned to ensure the signal order and pattern is different when the wheel or sprocket travels clockwise as opposed to travelling anticlockwise to enable the control means to detect the 5 direction in which the vehicle is travelling. Preferably the outputs of the sensors generate a series of square waves and the sensors are positioned such that the output square waves are 90 degrees out of phase. When a change in direction occurs, one of the square waves will lead the other of the square waves and thus enable direction of movement to be determined. 10 The toothed wheel or sprocket may typically be fitted to part of the vehicles drive train for example to a vehicle wheel to sense rotation of the vehicle wheel and therefore ground speed of the vehicle. Preferably the control means is adapted to sense any predetermined, pre programmed low speed threshold to prevent operation of the herbicide applying 15 means at speeds below levels considered appropriate for the type of work being carried out. Whilst a particular form of speed sensing means is described above, other speed sensing means may be used. The vegetation recognition means suitably comprises at least one colour 20 sensor for sensing the colour of and thus the presence of vegetation. Preferably the vegetation recognition means includes at least one light source for illuminating an area in which vegetation to be treated is located or likely to be located and the at least one colour sensor is adapted to detect light reflected from the vegetation whereby to detect the presence or absence of vegetation in the area 25 illuminated by the light source. Preferably to increase the accuracy of the light directed towards the area in which the vegetation is located or likely to be located, the light emitted by the light source suitably comprises a light source which emits parallel light rays of the required colour and intensity. Alternatively, one or more light sources may be used in association with collimators which serves to make the light 30 rays emitted from the light source/s parallel. The at least one light source may be arranged forwardly of or rearwardly of the colour sensor relative to the direction of movement of the vehicle and is angled so that the colour sensor can receive diffused reflected light from an underlying surface which may contain the vegetation.

8 The at least one light source comprises one or more light emitting diodes such as a super bright LED or LED's however other light sources may be used. The colour sensor suitably comprises a primary colour sensor. Most suitably the primary colour sensor comprises Red, Green and Blue colour sensors and 5 suitably includes respective photodiodes provided with Red, Green and Blue colour filters respectively. By measuring the intensity of the reflected light signal received by each sensor, a colour can be sensed and therefore vegetation to be treated can be sensed by sensing the colour of the vegetation. Preferably the herbicide applying means comprises one or more spray heads 10 or nozzles connected to the herbicide supply. Preferably the spray heads or nozzles are electronically, electrically or mechanically activated. Typically the spray heads or nozzles are solenoid or pneumatically actuated. Preferably the control means controls the operation of the spray heads or nozzles. Preferably the control means may be selectively programmed for different types or designs of spray head or nozzle 15 and/or height of the nozzle relative to the vegetation to be treated such that the control means may adjust the operation of the herbicide applying means in accordance with the aforesaid parameters. The apparatus may additionally include at least one controlled droplet applicator for applying a fine spray to vegetation comprised of droplets precisely 20 controlled to the pre determined size and shape known to produce the best results in the application being carried out at the time. Preferably the controlled droplet system is controlled by the control means in accordance with the ground speed of the vehicle as sensed by the speed sensing means. The controlled droplet applicator may be selectively made operative or non-operative by an operator as required. 25 Preferably the controlled droplet applicator comprises a sectoralised controlled droplet applicator (CDA) head that delivers the product in the size and shape of arc needed to provide full coverage of the treatment area. A product recovery and recirculation system (pick up) is designed to recover product falling through the unused sector of the CDA spray head. The recovery system may utilize 30 either gravity or a vacuum pick up. The CDA head is suitably pressure fed by a pressure regulated pump Preferably a mounting platform or module is provided on the vehicle for mounting the multiple spray heads and associated components of the two spraying systems. The mounting platform may additionally mount the lighting and sensing 9 components of the vegetation recognition system. The mounting platform will preferably also carry a weed wiping means around its periphery for direct contact with weeds as also further described below. Most preferably the mounting platform is mounted for transverse movement 5 relative to the vehicle. Adjustment means may be provided to adjust the position of the mounting platform to cause the platform to automatically move transversely to maintain a constant line and position relative to the kerb. The mounting platform may be moulded in one piece with all of the attachments moulded in ready to take the two different kinds of spray equipment, the 10 vegetation recognition system and the weed wiping means. The weed wiping means is provided for wiping taller weeds or other vegetation with herbicide irrespective of the direction of travel and for this reason may be positioned at both the front and rear of the platform. The weed wiping means is suitably sufficiently flexible to track the edge of the kerb and channel and to change 15 shape to conform to the shape and style of the kerbing. The weed wiping means can treat a strip such as an 800mm strip at the edge of a road and ensures a straight line is defined on both edges of the strip to provide a neat finish. The weed wiping means wipes tall weeds which may otherwise not be effectively treated by the spray system. The weed wiping means may comprise a 20 brush, wick or pad. The weed wiping means are suitably monitored and moisture controlled by an electronic controller to ensure accurate dosing and to prevent the weed wiping means from becoming over saturated and dripping onto the ground or non-target areas. The electronic controller may be separate from or part of the main control means. Preferably the weed wiping means can be quickly and easily 25 replaced on an as required basis via for example clip on attachments and quick release, drip proof hose couplings. The present invention in a further aspect provides a method for treating vegetation with herbicide, including the steps of: (i) recognizing and detecting said target vegetation; 30 (ii) sensing ground speed and direction of a vehicle carrying herbicide applying means; and (iii) varying the timing of application of herbicide and also the pressure and/or amount of applied herbicide on an infinitely variable basis in accordance with measurement of the ground speed and direction of vehicle wherein said speed is also measured on an infinitely variable basis According to another aspect of the invention, there is provided an apparatus for treating target vegetation with herbicide, the apparatus comprising one of a platform, carriage and module, hereinafter referred to as a "platform", that is mountable to a vehicle to permit the platform to travel over an area to be treated; at least one spray head arranged on the platform to spray target vegetation with herbicide when actuated; a sensor that is operatively arranged with respect to the platform and is configured to sense a speed and direction of travel of the platform; a controller for receiving input from the sensor, the controller being operatively connected to the spray head(s) to control a volume of herbicide applied by the spray head(s) according to the speed and direction of travel of the platform; and a weed wiping means arranged on the platform to perform a weed wiping operation on target vegetation that may not be treated effectively with the spray head(s) when the platform travels over the area to be treated. A number of the spray heads may be arranged on the platform and may include spray nozzles for spraying target vegetation. The spray heads may include at least one head of a controlled droplet applicator for controlled droplet application to the target vegetation. The controller may be configured to control the spray head(s) so that herbicide is applied to the target vegetation at a consistent concentration per unit area irrespective of speed of the platform. The controller may be configured to use a signal generated by the sensor to maintain the spray head(s) in an inactive state until the platform reaches a predetermined speed in a particular direction or falls below a predetermined speed in a particular direction. The weed wiping means may be arranged on at least leading and trailing edges of the platform and functions as a shroud for the spray head(s). A vegetation recognition and detection system may be arranged on the platform for recognition and detection of the target vegetation, the system being connected to the controller so that the controller can actuate the spray head(s) upon recognition and detection of the target vegetation. The vegetation recognition and detection system may be positioned with respect to the spray head(s) so that the controller has sufficient time to actuate the spray nozzles to spray recognised vegetation.

The controller may be configured to use the signal from the sensor and a position of the vegetation recognition and detection system to determine an appropriate time at which the spray head(s) are actuated. The vegetation recognition and detection system may include at least one light source for illuminating an area in which vegetation to be treated is located or is likely to be located and at least one means of sensing and identifying target vegetation in the area illuminated by the light source. The sensor may be configured to sense the speed of travel at a predetermined rate to determine acceleration and deceleration of the platform. The controller may be configured to control the volume of herbicide applied by the spray head(s) according to said acceleration and deceleration. The invention extends to a method of treating target vegetation with herbicide using the apparatus as claimed in any one of the preceding claims. Brief description of the drawings In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention. The preferred embodiment of the invention has been described in relation to apparatus for applying herbicide to vegetation such as weeds. It will be appreciated however that the invention may be used for applying other liquids for example other chemicals, fungicides or fertilisers to vegetation other than weeds and thus the reference to herbicide throughout the specification includes other liquids as referred to above and the reference to vegetation includes vegetation other than weeds. In the drawings: Fig. 1 is a schematic block diagram of the vegetation treatment apparatus according to an embodiment of the invention; Fig. 2 is a schematic side view of a vehicle provided with the vegetation treatment apparatus of Fig. 1. Figs. 3 and 4 are schematic front and plan views of the vehicle of figure 2; Fig. 5 is a block circuit diagram of the vegetation detection system and associated herbicide spraying system of the invention; Fig. 6 illustrates schematically the speed sensors for use in the apparatus; Fig. 7 illustrates the square wave output generated by the speed sensors; Fig. 8 illustrates schematically the platform carrying the vegetation treatment devices and vegetation recognition means; Fig. 9 is a block circuit diagram similar to figure 5 describing another embodiment of the invention; Fig. 10 is a block circuit diagram similar to figure 5 describing a further embodiment of the invention; Fig. 11 represents a block diagram illustrating the software utilised in the invention. Detailed Description of a Preferred Embodiment Referring to the drawings and firstly to figures 1 there is illustrated schematically vegetation treatment apparatus 10 according to an embodiment of the 11 invention which is adapted to be mounted to a vehicle for treating vegetation such as weeds growing in or adjacent to a roadway with herbicide as the vehicle moves along a roadway. The apparatus 10 in this embodiment includes a spray head 11 having a plurality of hydraulic spray nozzles 12 for spot spraying of mature or target 5 vegetation, controlled droplet spray heads 13 for mist spraying of hidden seedlings or the like and weed wiping means 14 for herbicide application to taller vegetation. A herbicide mix is supplied to the spray nozzles 12, the herbicide mix being derived from water or other liquid carrier held within a storage tank 15 and supplied from a pump 16 connected to the tank 15 and herbicide concentrate injected into a 10 supply line 17 connecting the pump 16 to the nozzles 12 using dosing pumps 18 connected to respective herbicide concentrate supply containers 19. In the embodiment illustrated two such dosing pumps 18 and associated containers 19 for injection of two different types of herbicide into the supply lines 17 are shown however it will be appreciated that one such dosing pump 18 is required where only 15 one type of herbicide is to be used in the apparatus 10. Alternatively more than two dosing pumps may be used where more than two different types of herbicide are to be used. A similar arrangement to that described above is used for the supply of herbicide to the controlled droplet applicator spray heads 13. Thus the controlled 20 droplet applicator spray heads 13 are connected via a supply line 20 to a further pump 21 connected to the storage tank 15. A further dosing pump 22 is connected to the supply line 20 to inject herbicide into the supply line 20 from a further herbicide container 23. Where more than one type of herbicide is to be sprayed from the spray heads 13, additional dosing pumps and associated herbicide containers are 25 provided to inject different herbicides into the supply line 20 to the spray heads 13. The apparatus 10 additionally includes a vegetation recognition and detection system 24 for recognising and detecting target vegetation to be sprayed by the spot spray nozzles 12 as described further below. The apparatus 10 further includes a vehicle speed sensor 25 (also described further below) for sensing the ground speed 30 of the vehicle to which the apparatus 10 is mounted. A controller 26 which may be a Programmable Logic Controller (PLC) is provided to control all of the spray treatment operations of the apparatus 10 in accordance with the ground speed of the vehicle as sensed by the speed sensor 25 and in the case of the spray nozzles 12 when the presence of vegetation to be sprayed 12 is recognised and detected by the vegetation recognition system 24. Thus the controller 26 ensures that one or more spray nozzles 12 are supplied with herbicide and automatically activated at the appropriate time for spray of herbicide from one or more of the nozzles 12 and further ensures that the nozzles 12 are supplied with 5 herbicide for the correct duration such that the nozzles 12 deliver the right concentration and volume of herbicide as specified by the herbicide manufacturers irrespective of the vehicle ground speed being travelled at the time. As shown in Figs. 2 and 3, the vegetation treatment apparatus 10 is mounted to a vehicle 27 which may be any form of vehicle driven or capable of being driven by 10 any form of motive means such as an internal combustion engine or electric motor The spray nozzles 12 are spaced transversely across the vehicle 27 and the spray head 11 carrying the spray nozzles 12 extends to one side of the vehicle 27 to enable vegetation at various transverse positions in the path of forward movement of the spray head 11 with the vehicle 27 to be sprayed. 15 The vegetation recognition and detection system 24 as shown in Fig. 5 is also positioned forwardly of the spray nozzles 12 of the spray head 11 such that the controller 26 has sufficient time to turn the spray nozzles 12 on after vegetation to be sprayed is recognised and detected. The vegetation detection system 24 as shown in Fig. 5 comprises a plurality of 20 RGB colour sensor modules 28 for recognising vegetation to be treated by sensing the colour of the vegetation in the path of movement of the vehicle 27, the modules 28 being arranged at spaced positions across the vehicle 27. A main system control processor 29 (see Fig. 5) is connected to the plurality of modules 28 (only one of which is shown) to receive signals therefrom. Each 25 colour sensor module 28 includes a microcontroller 30 which controls one or more RGB colour sensors 31 which use photodiodes and colour filters to enable the colour of an object to be sensed. The microcontroller 30 also controls one or more light sources 32 such as light emitting diodes (LEDs) typically superbright LEDs to overcome ambient light and provide an accurate light signal which can be detected 30 by the sensor/s. The main processor 29 generates timing signals to be sent via the microcontrollers 30 to the LEDs 32 to cause pulses of light to be emitted from the LEDs 32. The main processor 29 also receives input signals from the colour sensors 31 via micro controller 30 which represents light from the LEDs 32 which has been 13 reflected. The processor 29 analyses the signals received from the sensors 31 using period measurement techniques to provide high speed detection of vegetation and provide weed recognition output signals to the controller 26. The controller 26 additionally receives an input from the speed and direction 5 sensor 25 for automatic triggering of the spray nozzles 12 when they pass over the vegetation identified by the vegetation recognition unit 24 and also controls the duration of spraying. The signal from the speed sensor 25 is also used for the control of operation of the controlled droplet spray heads 13. The speed sensor 25 may be any form of speed sensor as is known in the art 10 however in this embodiment and as shown in Fig. 6, the sensor 25 comprises a pulse type speed sensor where a toothed wheel or sprocket 33 is mounted for rotation on a drive train shaft 34 of the vehicle 27, the toothed wheel 33 having teeth 35 which pass by a sensor device 36 located adjacent the periphery of the toothed wheel 33 which generates a pulse or pulses as each tooth 35 on the wheel 33 moves 15 past the sensor device 36. For speed and direction sensing, a pair of sensor devices 36 which in this embodiment comprise variable reluctance sensors which are spaced circumferentially around the toothed wheel 33 and positioned such that their outputs are 90 degrees out of phase. The outputs from the sensor devices 36 provide output square waves as shown in Fig. 7 which are 90 degrees out of phase with each other. 20 Use of a pair of sensor devices 36 enables forward or reverse direction of movement of the vehicle 27 to be sensed by the controller 26 which determines which of the output square waves is leading the other. The speed sensor 25 is connected to the controller 26 such that the triggering and spraying duration of each spray nozzle 12 and operation of the controlled droplet 25 spray heads 13 can be controlled in accordance with the ground speed of travel of the vehicle 27. The controller 26 can also use the signal derived from the speed sensor 25 to maintain the apparatus 10 in an inactive state until the vehicle 27 reaches a predetermined speed, or falls below a predetermined speed (i.e. stopped or operates in the reverse direction). 30 The spray heads and other herbicide application devices may be mounted to a common platform or carriage 37 as shown in cross section in Fig. 8 and in dotted outline in Fig. 4. The platform or carriage 37 is slidably mounted to the vehicle 27 for lateral movement under the control of an actuator 38. The platform or carriage 37 carries at leading and trailing ends weed wiping means 14 which typically extend 14 substantially horizontally and across the vehicle 27. Herbicide is supplied to the weed wiping means 14 through supply line 39 and pump 40 connected to the tank 15. Herbicide concentrate is held within a container 41 and injected into the supply line 39 by an injector 42. A control valve 43 is provided in the line 39 to control the 5 application of the herbicide to the weed wiping means 14. Both the control valve 43 and injector 42 are connected to the controller 26 to be controlled thereby. The platform or carriage 37 also supports the controlled droplet applicator heads 13 and spray nozzles 12. The weed wiping means 14 also functions as a shroud or cover to inhibit fine mist from nozzles 12 and controlled droplet applicator 10 heads 13. The vegetation recognition system 24 may also be located on the platform 37. In another embodiment as shown in FIG 9 main processor 29, microcontroller 30 and said one or more RGB sensors 31 may be dispensed with and replaced by the arrangement shown in FIG 9 where camera(s) 41 are used to recognise and 15 detect target vegetation such as weeds. Camera(s) 41 may be one or more cameras which preferably are rugged environment cameras such as, for example, a USB type camera inclusive of USBuEye RE industrial cameras manufactured by Imaging Development Systems as described in www.ids-imaqinq.com. This camera is sealed to the environment and can be washed down with a pressure jet. Such a camera 20 may also be subjected to a steam of compressed air to clean the lens of the camera. This may be obtained from a device such as, for example, a SuperAir Wipe obtainable from EXAIR CORPORATION. Details are available at www.exair.com. Such stream of compressed air may also be ionized by a device known as Super Ton Air Wipe also obtainable from Exair Corporation. 25 There is also provided PC 40 which is interfaced with PLC 26 as shown. The function of PC 40 is to capture the images from said one or more cameras 41 wherein the image(s) are analysed for patterns corresponding to colour, shape and size of the target vegetation. There may be used suitable software to accomplish this such as, for example, COMMON VISION BLOX having a website at 30 www.commonvisionblox.com and marketed by STEMMER IMAGING from Austria. The resultant signals are then sent to PLC 26 and a similar process occurs as described above in FIG 5. In another embodiment as shown in FIG 10 PC 40 and PLC 26 are replaced by PC 42 which together with interfaces 43, 44 and 45 replicate the functions of PC 15 40 and PLC 26. In this embodiment the function of PLC 26 is replaced by a software PLC programme within PC 42. PC 42 can comprise a suitable laptop computer which may be rugged in character and which incorporates a processor similar to INTEL QUADCORE technology. 5 In FIG 11 there is provided a block diagram illustrating the software employed by the invention. Thus at the start 50 the vegetation treatment apparatus 10 is energised and the vegetation images are captured continuously by vegetation recognition and detection system 24 which are then forwarded to microprocessor 29. If target vegetation in the form of a weed is recognised by microprocessor 29 then an 10 appropriate signal or flag is sent or made available to PLC 26 shown in phantom. This does not happen if target vegetation is not recognised by microprocessor 29 as shown at 51. At start 50 the speed and direction sensing sensor 25 is also activated and makes a continuous signal available to PLC 26. Subsequently PLC 26 based on a number of mathematical functions makes a 15 number of decisions. One decision is indicated at 52 which basically asks the question is the vehicle 27 moving forwardly or reversing or is stationary? Upon answering this question in the positive the speed of the vehicle is then calculated at 53 which is infinitely variable. A range or sequence of speeds travelled by vehicle 27 is then stored or saved to memory at 54 to facilitate calculation of acceleration or 20 deceleration trends at 55. This information is used within PLC 26 to continually update the time when spray nozzle 12 and/or CDA heads 13 will be actuated as shown at 56. Simultaneously if the vehicle 27 is reversing or is stationary the PLC 26 ensures that nozzles 12 and/or CDA heads 13 are turned off as shown at 57. This is 25 important to ensure that if image capture device 24 is stationary the nozzles 12 and/or CDA heads 13 are shut off. Also it is important that vegetation treatment apparatus 10 be operational if the vegetative recognition and detection system 24 is mounted forwardly of nozzles 12 and/or CDA heads 13 in the direction of travel. At 56 the timing of optional shutter activation if vegetation, recognition and 30 detection 24 is in the form of one or more cameras is also determined as well as optional backlighting or illumination of the target area is required. Also at 56 the required herbicide pressure which is infinitely variable within a desirable predetermined range of 0.1 to 5.0 bar is also determined.

16 The PLC 26 then at 57 then asks the query should the nozzles 12 be activated? If the answer in the affirmative nozzles 12 are then actuated at 58. If in the negative this is determined at 59. Also at 59A the PLC 26 facilitates the adjustment of the pressure of nozzles 5 12 as may be required. Another preferred embodiment of the invention is shown at 58 concerning the distance between nozzles 12 and vegetation recognition and detection system 24 as shown in FIG 4. The distance is constant on a vehicle 27 having a rigid chassis with 10 conventional steering but is variable on an articulated vehicle 27 when the vegetation recognition and detection system 24 and nozzles 12 are located on opposite ends of vehicle 27. This distance is therefore measured at 59B and saved to memory for trend calculations at 60. Such trends in terms of rates of change of distance are calculated at 61 and the information is made available and used in the calculations at 15 56. There is also shown in FIG 11 PLC 26 inputs 62, 63 and 64 and PLC outputs 65, 66 and 67. In use, the vehicle 27 is driven along an area to be treated such as a roadway and when one or more of the RGB sensors modules 28 of the vegetation recognition 20 system 24 recognise and detects the presence of vegetation anywhere in its or their field of view across the vehicle 27, as determined by their associated microcontroller/s 30 and main control processor 29, the processor 29 will send vegetation recognition detection signals to the controller 26. In accordance with the signal received from the processor 29, the controller 26 may determine which spray 25 nozzle 12 should be actuated or supplied with herbicide to cause vegetation to be spot sprayed. In addition, the controller 26 from the speed signal received from the speed sensor 25, can determine the time at which a spray nozzle 12 should be turned on (determined from the distance between the vegetation recognition unit 24 and spray nozzle 12 and the ground speed of the vehicle). The controller 26 may 30 also govern the concentration of herbicide to be applied by varying the operation of the herbicide concentrate dosing or injecting pumps 18 and the pressure and/or volume of herbicide to be applied by varying the operation of the supply pump 16 to the nozzles 12. If the ground speed of the vehicle increases or decreases, the controller 26 will from the speed signal received from the sensor 25 change the time 17 at which the nozzles 12 commence operation and the duration of their operation. The controller 26 may additionally control changes to the pressure and/or volume of the herbicide applied to the nozzles 12 and/or vary the herbicide concentration. The controller 26 will thus ensure that irrespective of the ground speed of the vehicle 27, 5 vegetation to be treated will receive the same volume and concentration of herbicide. Further, irrespective of the actual location of the vegetation in the area being travelled by the vehicle 27, it will be treated by herbicide. Each of these spray nozzles 12 has its own designated target area so the controller 26 only triggers those nozzles 12 that need to be activated to treat weeds falling within this designated 10 area. If it is desired to actuate the controlled droplet applicator (CDA) heads 13, the operator can through the controller 26 manually initiate operation of the applicator heads 13 which will cause the generation of fine controlled sized droplets of herbicide from the applicators 13. The volume of herbicide sprayed from the CDA 15 heads 13 may be varied by the controller 26 in accordance with the ground speed and direction of the vehicle 27 as sensed by the sensor 25 so that the same concentration of herbicide is applied irrespective of the ground speed. Thus the controller 26 regulates and varies the volume of chemical applied by matching the dosing and volume of the chemical mix to the applications according to the forward 20 speed of travel. The nozzles 12 and CDA heads 13 can be actuated at the same time for different purposes and each may apply different products or a different mix of products at the same time. The flow of herbicide to the weed wiping means 14 is automatically monitored and controlled to ensure herbicide cannot drip, or run onto non-target areas. 25 The herbicide supplied to the weed wiping means 14 may be a different product or product concentration to that being used in either of the spot spray or CDA systems. In a variation of the above process and as described in the FIG 9 embodiment the cameras 41 will carry out a similar function as described above in regard to the RGB colour sensors 31. Also the function of microcontrols 30 and main system 30 control processor 29 is replaced by PC 40. In regard to the FIG 10 embodiment the functions of controller 26 as described above is replaced by PC42 and associated software as described above. The present invention thus provides vegetation treatment apparatus which has the ability to precisely adjust the time of commencement of operation and the 18 duration of operation of spray heads of spraying systems over an infinitely variable range of speeds within the recommended minimum and maximum operating speeds considered safe and practical for a spray unit of this kind when carrying out spraying activities on a road network. This is designed to ensure an active spray head only 5 opens immediately upon approaching a target and deactivates again as soon as the target is treated and moves out of range, which in most cases would be an active time only measurable in milliseconds. This feature is designed to ensure only the proper dose of herbicide is applied to a given target. Due to the complete integration of the two spraying systems via the speed sensing device 25 and controller 26, they 10 will both cut out as soon as the vehicle ceases movement and they will both remain on standby until forward motion is detected again. In addition to the above it will also be appreciated from the foregoing and in particular FIG 11 that the invention for the first time provides a vegetation treatment apparatus which during operation of nozzles 12 allows the timing and pressure or 15 amount of herbicide to be determined on an infinitely variable basis when vegetation recognition and detection system 24 is actuated in accordance with the ground speed and direction of vehicle 27. In this situation the ground speed is also measured on an infinitely variable basis. In this regard "infinitely variable" means that the above parameters can be measured at any suitable instant of time. For example 20 these measurements or calculations may be made 100 times per second or intervals of 10 milliseconds when vegetation and detection system 24 is operational. This has the desired advantage unlike the prior art that rates of acceleration and deceleration can be incorporated into the timing of application of herbicide. This also facilitates application of herbicide substantially instantly when the 25 start of a zone of target vegetation is determined and shutting off application of herbicide when the end of the zone is reached. The terms "comprising" or "comprises" as used throughout the specification are taken to specify the presence of the stated features, integers and components referred to but not preclude the presence or addition of one or more other feature/s, 30 integer/s, component/s or group thereof. Whilst the above has been given by way of illustrative embodiment of the invention, all such variations and modifications thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein described.

Claims (12)

1. An apparatus for treating target vegetation with herbicide, the apparatus comprising one of a platform, carriage and module, hereinafter referred to as a "platform", that is mountable to a vehicle to permit the platform to travel over an area to be treated; at least one spray head arranged on the platform to spray target vegetation with herbicide when actuated; a sensor that is operatively arranged with respect to the platform and is configured to sense a speed and direction of travel of the platform; a controller for receiving input from the sensor, the controller being operatively connected to the spray head(s) to control a volume of herbicide applied by the spray head(s) according to the speed and direction of travel of the platform; and a weed wiping means arranged on the platform to perform a weed wiping operation on target vegetation that may not be treated effectively with the spray head(s) when the platform travels over the area to be treated.

2. The apparatus as claimed in claim 1, in which a number of the spray heads are arranged on the platform and include spray nozzles for spraying target vegetation.

3. The apparatus as claimed in claim 2, in which the spray heads include at least one head of a controlled droplet applicator for controlled droplet application to the target vegetation.

4. The apparatus as claimed in any one of the preceding claims, in which the controller is configured to control the spray head(s) so that herbicide is applied to the target vegetation at a consistent concentration per unit area irrespective of speed of the platform.

5. The apparatus as claimed in any one of the preceding claims, in which the controller is configured to use a signal generated by the sensor to maintain the spray head(s) in an inactive state until the platform reaches a predetermined speed in a particular direction or falls below a predetermined speed in a particular direction.

6. The apparatus as claimed in any one of the preceding claims, in which the weed wiping means is arranged on at least leading and trailing edges of the platform and functions as a shroud for the spray head(s).

7. The apparatus as claimed in any one of the preceding claims, in which a vegetation recognition and detection system is arranged on the platform for recognition and detection of the target vegetation, the system being connected to the controller so that the controller can actuate the spray head(s) upon recognition and detection of the target vegetation. 20

8. The apparatus as claimed in claim 7, in which the vegetation recognition and detection system is positioned with respect to the spray head(s) so that the controller has sufficient time to actuate the spray nozzles to spray recognised vegetation.

9. The apparatus as claimed in claim 8, in which the controller is configured to use the signal from the sensor and a position of the vegetation recognition and detection system to determine an appropriate time at which the spray head(s) are actuated.

10. The apparatus as claimed in claim 8 or 9, in which the vegetation recognition and detection system includes at least one light source for illuminating an area in which vegetation to be treated is located or is likely to be located and at least one means of sensing and identifying target vegetation in the area illuminated by the light source.

11. The apparatus as claimed in any one of the preceding claims in which the sensor is configured to sense the speed of travel at a predetermined rate to determine acceleration and deceleration of the platform, the controller being configured to control the volume of herbicide applied by the spray head(s) according to said acceleration and deceleration.

12. A method of treating target vegetation with herbicide using the apparatus as claimed in any one of the preceding claims.