GB2214046A

GB2214046A - Plant profiling sensor

Info

Publication number: GB2214046A
Application number: GB8900547A
Authority: GB
Inventors: Barry D Douglas
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1988-01-19
Filing date: 1989-01-11
Publication date: 1989-08-31
Anticipated expiration: 2009-01-11
Also published as: DE3900223A1; DE3900223C2; IT1228487B; GB2214046B; GB8900547D0; FR2626081A1; IT8919130A0; FR2626081B1

Description

1 1 1 PLANT PROFILING SENSOR2 2 14 Cj 4 u! Details of spraying apparatus

which can use the apparatus of the present invention to sense the presence of plants and which sprays only areas containing plants are disclosed in our copending application entitled "Control System For Uniform Spraying of Plants"; filed on even date herewith.

The present invention relates to apparatus for spraying plants with agricultural solutions, -such as pesticides or fungicides, and more particularly, to sensors which detect the presence or absence of plants and develops signals which cause a sprayer to supply solutions only to areas containing plants.

Air sprayers have been employed for many years to apply pesticides, fungicides and other agricultural liquid solutions to the foliage and fruits of orchards, groves and vineyards. An air sprayer generally employs a liquid flow system and an air flow system designed to work together to deliver a controlled air-spray pattern which penetrates the foliage and fruits of a plant. The -liquid flow system of the sprayer includes a holding tank mounted on a trailer frame, a plurality of spray nozzles, a pump which is driven by an engine on the trailer frame or by a power take off of a tractor which pulls the spray trailer, conduits and valving for delivering the spray solution from the tank to the pump and subsequently to nozzles under regulated pressure. The air flow system employs a blower assembly 1 1 2 having at least one discharge opening f or directing an air blast generally transversely of the path of travel of the sprayer. The spray nozzles are disposed in the discharge opening to deliver atomized spray solutions f or entrainment in the air blast. One type of air sprayer for spraying orchards includes a centrifugal or squirrel cage fan which is disposed behind the spray tank on the sprayer trailer.

The fan includes a housing having air outlet openings oriented transversely of the path of travel of the sprayer, and an inlet opening extending rearwardly and longitudinally of the sprayer path of travel. Normally, a pair of deflector housings -are connected to each outlet opening.

Each housing has a "fish tail" shape and arcuate discharge opening which extends transversely of the sprayer. The arcuate opening is adapted to deliver an air blast extending over an outward, widely diverging pattern. Typically, the deflector housings are adjustably mounted to the respective centrifugal fans so that the air blast may be directed at various angles relative to the horizontal. This type of spray is normally used to spray two rows of plants at one time, the deflector housing being adjusted to direct the air blast in opposite transverse directions relative to the path of movement of the sprayer. Such sprayers deliver the spray solution over a predetermined area irrespective of the presence or absence of plants along the row of plants.

This can result in a substantial' waste of spray -solution when plants are smaller than average or when plants are 9 11 It 1 3 missing from a row. In addition to the cost of the spray solution it is also desirable to limit the quantity of chemicals applied to orchards because of chemical emission standards which have been established and are monitored by the Federal Government.

- The present invention provides a plant profiling sensor for sensing the presence and profile of nearby plants, said sensor comprising:- a plurality of plant sensing units each for detecting the presence of plants in a respective predetermined area, the plant sensing units being mounted in an array with said areas adjacent to each other, the profiling sensor producing output signals corresponding to the areas which contain plants.

The plant profiling sensor may provide signals which cause an associated sprayer to turn on sprayer nozzles to cover only areas which contain plants to be sprayed. In a preferred embodiment of the invention, a plurality of sensing units mounted around the upper periphery of the sprayer each sense the presence or absence of plants in a narrow field of view and each sensing unit provides a signal which actuates a corresponding spray nozzle that provides spray solution to an area in which a plant is sensed. Each of the sensing units may transmit energy which is partially reflected from a portion of a plant located within the narrow field. The reflected energy returns to the sensing unit where a signal pulse is developed. The signal pulse

4 is coupled to computing means which uses the pulse to cause a spray nozzle to be actuated so that a spray solution is directed toward a portion of the plant detected by the corresponding sensing unit. To prevent cross-talk between individual sensing units the sensing units are multiplexed with each sensing unit sending out a short burst of energy while the other sensing units are disabled. Substantially only the energy which returns to the sending unit is used in detecting nearby plants. Each of the other sensing units then takes its turn sending out pulses of energy and using any returning pulse to detect plants in its field.

An embodiment of the invention will now be described by way of example and with reference to the drawings wherein:- Fig. 1 is a side elevation illustrating an air sprayer apparatus which includes the plant profiling sensor of the present invention.

Fig. 2 is a front elevation of the air sprayer apparatus disclosed in Fig. 1.

Fig. 3 discloses details of-a plant sensing unit of the present invention.

Fig. 4 is a diagrammatic illustration of a plant profiling sensor of the present invention for use in an air sprayer apparatus.

Referring now more particularly to Figs. I and 2, an air sprayer apparatus 10 for orchards and the like includes a main frame 11 which is movable On'a pair of wheels 12, 13. A tongue 17 is adapted for connection to a tractor or other source of propulsion through an orchard or vineyard. A holding tank 18 for carrying an agricultural spray solution is mounted over the wheels 12, 13 and an engine 19 f or operating a pump 22 and a blower assembly 23 is mounted on the front portion of frame 11. The blower assembly 23 includes an air inlet opening 24 and a plurality of outlet openings 27 adjacent to a plurality of spray nozzles 28.

The blower assembly provides an air blast through-the outlet openings 27 which -causes solution from nozzles 28 to be blown outwardly onto plants (not shown) adjacent to sprayer 10. A plurality of plant sensing units 29a - 29h (Figs. 1 4) mounted along the front portion of sprayer apparatus 10 each transmits and receives energy pulses to sense the presence or absence of plants in conical areas 30a - 30h (Fig. 2) extending radially outward from apparatus 10.

Sensing unit 29a transmits and receives energy pulses to sense any plant present in conical area 30a; sensing unit 29b transmits and receives energy pulses to sense any plant present in conical area 30b, etc.

A control box 34 (Fig. i)-having means for mounting on a front portion 10a of sprayer apparatus 10 is connected to apparatus 10 by a flexible signal cable 35. The control box 34 includes a plurality of push buttons or other controls (not shown) for selecting spray density and other parameters by a human operator. The control box 34 can be unhooked from the sprayer apparatus and moved into the cab of a tractor (not shown) to provide convenient selection of 6 spray control parameters by the human operator. A speed sensor 40 (Fig. 1) connected to one of the wheels 12, 13 provides speed signals proportional to the ground speed of the sprayer apparatus.

As the sprayer apparatus 10 moves along the ground each of the plant sensing units 29a - 29h (Figs. 2, 4) senses the presence or absence of plants in the corresponding conical areas 30a - 30h and sends a "plantpresent" -or "plantabsent" signal to a computer 41 (Fig. 4) which actuates a flow control to corresponding spray nozzles 28 as described in the copending patent application entitled "Control System for Uniform Spraying of Plants" listed above.

The plant profiling sensor of the present invention (Figs. 3, 4) includes a pair of pulse generator/receiver boards 43, 44 which provides signal pulses to plant sensing units 29a - 29h. A pair of multiplexers 48, 49 directs the signal pulses sequentially to the sensing units.

Multiplexer 48 directs a first signal pulse to sensing unit 29a causing unit 29a to transmit an ultrasonic beam in an area 30a (Fig. 2) along the right side of apparatus 10. if there is a plant in area 30a the plant reflects a portion of the ultrasonic beam back to sensing unit 29a which provides a return signal to board 43. A signal conditioning circuit shapes the return signal into a form usable by a computer 41. Computer 41 stores the return signal until spray nozzles 28 reach a position adja:cent to' the sensed plant.

Computer 41 then provides a valve actuating signal on an z _k 7 output line 42 which actuates nozzles 28 to provide fluid to conical area 30a and sprays a portion of the plant. A few milliseconds after sensing unit 29a receives the reflected ultrasonic beam, board 43 and multiplexer 48 provide a signal pulse to sensing unit 29b to determine the presence of a plant in area 30b. Signal pulses to sensing units 29c, 29d sequentially determine the presence of a plant in the areas 30c, 30d. The use of multiplexed signal pulses and the use of return signals - substantially only by the sensing units which transmit the ultrasonic beam prevent ultrasonic signals transmitted by one sensing unit from developing signals in adjacent sensing units.

Computer 41 can be programmed so that only signals reflected from nearby plants cause valve actuating signals to be coupled to output line 42. The placement and orientation of deflectors 63 can be adjusted to change the angle and size of the conical areas 30a - 30h (Fig. 2).

Multiplexer 49, pulse generator/receiver board 44 and signal conditioning circuit 51 provide signal pulses to plant sensing units 29e - 29h j_o sense,plants along the left side of sprayer apparatus 10. A smaller or greater number of sensing units can be used.

Each of the sensing units 29a - 29h includes an ultrasonic transducer 55 (Fig. 3) having an ultrasonic sensor 56 mounted in an end portion 57 of a cone 61. Cone 61 is secured to'sprayer apparatus 10 by a bracket 62 which is welded or otherwise secured to a portion of sprayer 8 apparatus 10. An ultrasonic deflector 63 is connected to a shield 67 by a threaded bolt 68. Shield 67 protects transducer 55 from plant and tree branches which may press against the sprayer apparatus 10. Transducer 55 vibrates to send a transmitted beam of ultrasonic energy toward deflector 63 which directs a beam 69 outward toward plants to be detected. A reflected beam 70 from the plants is directed to sensor 56 by deflector 63. The combination of shield 67 and cone 61 help protect sensor 56 from rain, dirt and spray from the spray nozzles. The shape of cone 61 limits the angle of energy transmitted toward the plants in area 30e. A blower (not shown) can be used to blow moisture and dirt from deflector 63 to prevent deflection of energy reflected from deflector 63.

An ultrasonic transducer 55 which can be used in the present invention is the Model 604142 manufactured by the Polaroid Corporation, Cambridge, Massachusetts. A pair of power conditioning circuits 74, 75 provide filtered DC voltage for pulse generator/receiver boards 43, 44. A pair of sensor interface circuits 76, 77 change computer control signals to the proper level for use by boards 43, 44. A pulse generator/receiver board 43, 44 which can be used is the Model 607089 manufactured by Polaroid Corporation.

The present invention discloses a plant profiling sensor having a plurality of ultrasonic sensors which each detect the presence of plants in, a predetermined area and develops signals which can be used to cause a spray nozzle i p il..

1 9 to spray liquid only within the area where a plant is detected. Multiplexers prevent sensors in adjacent areas from developing signals which cause liquid to be sprayed in areas without plants.

Although the present mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention at defined in the claims.

1

Claims

CLAIMS:

1. A plant profiling sensor for sensing the presence and profile of nearby plants, said sensor comprising:- a plurality of plant sensing units each for detecting the presence of plants in a respective predetermined area, the plant sensing units being mounted in an array with said areas adjacent to each other, said profiling sensor producing output signals corresponding to the areas which contain plants.

2. A plant profiling sensor as claimed in claim 1 wherein each of said sensing units transmits pulses of energy outward into a corresponding angular area and receives energy reflected from a plant in said corresponding angular area, the sensing units producing an output signal upon receipt of said reflected energy.

3. A plant profiling sensor as claimed in claim 2 wherein said sensing units are ultrasonic.

4. A plant profiling sensor as defined in claim 3 including a plurality of ultrasonic deflectors, each mounted to direct said energy pulses from a corresponding one of said sensing units into a corresponding one of said angular areas and direct said reflected energy to said corresponding sensing unit.

xI- 11

5. A plant profiling sensor as claimed in claim 2, 3 or 4 including means f or multiplexing operation of said sensing units to insure that energy transmitted outward from each of said sensing units develops an output signal substantially only in the sensing unit which transmitted the energy toward the plants.

6. A plant profiling sensor as defined in any preceding claim including shielding means Mounted between said sensing units and said plants to prevent damage to said sensing units by limbs and branches of plants.

7. A plant profiling sensor as claimed in any preceding claim including computer means connected to said sensing units for developing control signals corresponding to the profile of plants adjacent to said profiling sensor from the output signals.

8. A plant profiling sensor as claimed in claim 7 including means f or causing said computer to develop said control signals when said plants are less than a predetermined distance from said sensing units.

9. A plant sprayer including a plant profiling sensor as claimed in any preLceding claim and having a plurality of spray nozzles eadh respectively arranged to supply fluid to a corresponding one of said predetermined areas, said output a 12 signals being used to actuate the corresponding said spray nozzle to spray a plant detected in the area to be sprayed.

10. A plant sprayer as claimed in claim 9 when dependent upon claims 7 or 8 wherein said control signals are used to actuate the corresponding said spray nozzle when a plant is in the area to be sprayed.

11. A plant profiling sensor substantially as described with reference to or as shown in the drawings.

12. A plant sprayer substantially as described with reference to or as shown in the drawings.

j 4 Published 1989 atThe Patent Office, State House, 66171 Sligh XoIbornLorLdonWCIR4TP. Further copies maybe obtainedfrom ThePatent0ince. Mant. D10.3rUIPTinted by Multiplexiechr1ques ItdSt Mary Cray, Went, Con. 1187