Preliminary Design Review of Robot for Agriculture Automation

8/12/2019 Preliminary Design Review of Robot for Agriculture Automation

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Prel iminary Design Review of Robot for Agr iculture

Automation Team 2

Faculty Mentor : Dr Madhav Krishna, Dr Suril Shah

Student Mentor : Masum Kumar Lodha

Agriculture is mankinds oldest and yet itsmost important economic activity, providingthe food, fiber and fuel necessary for our survival. The advent of Human Civilization isoften marked with the rise of agriculture, and historically an important yardstick ofdevelopment has often been the advancement of agricultural methods. With the globalpopulation expected to reach 9 billion by 2050, the importance of technologicaldevelopment in agriculture becomes paramount. At the same time the economics ofagriculture around the world, combined with a constant shift of labor away from primarysector presents with new challenges.

The following project stands on the assumption that at this interesting juncture of history,robotics and automation can play a significant role in meeting agricultural productionneeds of society. Robotics paves the path to increased efficiency and productivity, byautomating various agrarian practices currently undertaken by farmers.

The main aim of this project is to build a lightweight autonomous robotic system that iscapable of carrying out the following farming operations with minimal human intervention:-

Traversing through the field without damaging the crops Diagnosis for lack of water, and accordingly report it to the farmer (or coordinate

with automatic water sprinkling system, if any) Carry a predefined payload of pesticides Doing visual analysis to identify need of sprinkling pesticides Sprinkling of pesticide on identified spots

Also, keeping in mind the environment in which the system shall be deployed, the planmust also incorporate other important goals:

Easy interface to farmer, to operate the system, which also justifies the systembeing mostly autonomous.

Low production cost of the system, especially if system has to be deployed indeveloping markets.

Climate resistance, since much of the system will face rough environmentalconditions during its operations. Also to ease the process of repair as much aspossible.


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Control and mechanism for robotic arm

Entity Definition

This system is responsible for detecting the infected leaves in the field by analyzing

them using the camera mounted on the front of the arm.

Scope

To be maneuverable enough so that the robot can take images of the plants from a

multitude of angles and be nimble enough to increase the effective reach of the robot for

other uses.

The Robotic Arm should:

1. Be able to move according to the system requirements.

2. Be capable of carrying a camera and other sensors and relaying information from these

to the system processor for real time processing and decision making.

3. Have the ability to target and spray pesticides.

Mechanical System

Arms are typically defined by 14 different parameters:

1. Number of AxesTwo axes are needed to reach any point in a plane. Three are

required to reach a point in space. Roll, pitch, and yaw control are required for full

control of the end manipulator.

2. Degrees of FreedomNumber of points a robot can be directionally controlled

around. A human arm has seven degrees; articulated arms typically have up to 6

Degrees of Freedom.

3. Working EnvelopeRegion of space a robot can encompass.

4. Working SpaceThe region in space a robot can fully interact with.

5. KinematicsArrangement and types of joints (Cartesian, Cylindrical, Spherical,

SCARA, Articulated, Parallel)

6. PayloadAmount that can be lifted and carried

7. SpeedMay be defined by individual or total angular or linear movement speed

8. AccelerationLimits maximum speed over short distances. Acceleration is given

in terms of each degree of freedom or by axis.


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9. AccuracyGiven as a best case with modifiers based upon movement speed

and position from optimal within the envelope.

10. RepeatabilityMore closely related to precision than accuracy. Robots with a low

repeatability factor and high accuracy often need only to be recalibrated.

11. Motion ControlFor certain applications, arms may only need to move to certainpoints in the working space. They may also need to interact with all possible points.

12. Power Source Electric motors or hydraulics are typically used, though new

methods are emerging and being tested.

13. DriveMotors may be hooked directly to segments for direct drive. They may also

be attached via gears or in a harmonic drive system.

14. ComplianceMeasure of the distance or angle a robot joint will move under a

force.

The three joints will be located at the base, elbow, and wrist. The elbow joint, with

separate the upper and lower arms, will be immobile except for the joints themselves.

Between all four joints, the client will be provided with a full 360 degree rotation among

the X, Y, Z axes and throughout the three primary planes of motion. Along with range, the

device will also be capable of obtaining the basic anatomical motions of flexion, extension,

pronation, supination, circumduction, abduction, adduction, opposition, reposition, and

rotation.


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The proposed mechanism for the robotic arm which will help in achieving our goal so that

it can cover the entire 3D plane is an Arm having six degrees of freedom (6DOF) which

is very important in mechanical systems for analyzing and measuring these types of

systems.


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The proposed design for the robotic arm would be:


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Components

Servo Motor - A servomotor is a rotary actuator that allows for precise control of angular

position, velocity and acceleration of the Robotic Arm.LensFor taking the pictures of the leaves.

PipeFor sprinkling of the pesticide.

RodsFor making different parts of the Robotic Arm.

Control System

This Sub-Systems task is to control the movement of the Arm. The decision making part

of the system will give commands to the Arm dealing with the desired location of the

camera/pesticide spray and the Arm has to manipulate the various movable parts in sucha manner that the desired position is achieved. The components of this sub-system are:

Movement Control: Movement control will be achieved by using servomotors. A

servomotor is a rotary actuator that allows for precise control of angular position, velocity

and acceleration. It consists of a suitable motor coupled to a sensor for position feedback.

It also requires a relatively sophisticated controller, often a dedicated module designed

specifically for use with servomotors. The servomotors movement is specified by sending


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Decision Making

Entity Definition

The robot is largely expected to be autonomous, and hence requires an intelligentDecision Making mechanism. The Decision Making (or the AI) is a subsystem that doeshigher-order planning, and computations essential for that, while the other subsystemsare assumed to follow the commands.

At the highest level the Decision Making is done to emulate the existing agrarianpractices that lie within the domain of the problem, such as Pesticide/Insecticide. The existing workflows employed by farmers shall be formalized as artificial agents.

This subsystem is also responsible for taking input from the various sensors andanalyzing the data, for the purposes of making these decisions. Also at a lower level ofhierarchy, the agent would also take care of issues such as error-correction,calculations relating to amount and location of pesticide sprays, and analyzingmeasurements from other onboard sensors such as temperature and humidity andprocessing to draw out various conclusions regarding the spraying of pesticides withacceptable degree of accuracy regarding the amount to sprayed, position to be sprayedat, along with sensing moisture in the soil and triggering the water sprinkler(s) in aparticular area.

Scope

The Robot should:

Calculate the relative position of crop to be surveyed Move the Robotic Arm Capture images of particular crop from different angles Detect presence of pests in crop Detect general diseases in crop Decide whether to spray pesticide at a given area Detect malfunctioning or fault in the system Decide whether a particular patch of soil needs water

Purpose

Autonomous Decision Making Pest Detection Abilities Disease Detection Detecting Soil Moisture Content Fault detection


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Phases of Operation

1. Determine moisture content of soil using moisture sensors at user defineddistances.

2. Whenever the Robot reaches the end of cropping line, trigger appropriate

sprinklers if moisture content is found to be low.3. Calculate the angle with which the arm is to be rotated in order to face the crop.

Signal the arm to be rotated by the required angle.4. Move camera to a predefined set of angles.5. Take image of crop at predefined angles.6. At each angle

a. Process the image obtainedb. Run algorithm to detect defect in crop via

i. Pest detectionii. Fungal detectioniii. Color based disease detection

c. Determine amount of pesticide/insecticide required to be sprayedd. Determining the exact area where the pesticide is to be sprayede. Sending the coordinates to the robotic arm and signaling it to spray

7. If once pesticide is sprayed stop imaging process for that particular crop/angle.8. Signal robotic arm to go back to original position.9. Signal the navigation system to move forward.10. At any point if a fault or malfunctioning is detected, all processing should stop,

the robotic arm should come to its original position and navigation system shouldbe instructed to navigate back to starting position.

Capabilities

Detection of Viral Diseaseso Chlorosis refers to the loss in the normal green coloration of leaves,

caused by iron deficiency, disease, Beet Western Yellows Virus (BWYV)or lack of sunlight. The chlorosis algorithm combines the red and greencomponents of the RGB space of the image and finds the yellowness ofthe leaf, which indicates how severe the chlorosis is.

o Necrosis is a disease that occurs in plants when there is a calciumdeficiency, due to which pectin is not synthesized and cell walls are not

bonded. The necrosis algorithm uses the blue component to separateleaves from the background and the green component to identify necroticregions.

Detection of Pestso Aster yellows mycoplasma (AY) can infect a wide range of plants. As a

result of this disease, plants become stunted and strikingly yellow. Theonly known vector of this disease is the aster leafhopper, and this diseasecan be controlled by spraying of insecticides.


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Detection of Fungal Diseaseso Anthracnose is a fungal disease, which is characterized by circular

lesions, which become elliptical and turn brown eventually. The centersoften fall out, leaving black margined holes in the leaf. A very minuteconcentration of pesticide has to be used.

Potential Challenges

The calculations for the various angles should be reasonably accurate. Appropriate diagnosis of the conditions. A crop should not be sprayed on again once it has been sprayed on. A crop should not be unnecessarily identified as defective. Malfunctioning of any kind should automatically be detected as soon as possible.

The Contro l Flow for Water ing Mechanism


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Control Flow for Pest icide Sprinkl ing


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Navigation System

Top View

Fig1: The basic Robot prototype

Entity Definition

This system is responsible for detecting and following the path in which the Robot

should move so that the pesticides that are being carried are delivered safely to each

and every plant without any wastage.

Scope

Description:

The Proposed model is a four legged Robot with a camera and a robotic arm with a

suction mechanism to spray pesticides etc

Functioning of Robot :

1)Path detection

2)Speed Control

3)Steering Control

The navigation system is composed of the following sub-systems. One system is tocontrol the path in which the Robot moves. The second one controls the linear speed of


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the Robot. The next one, controls the steering of the Robot, using the true path todetermine the wheel orientation angle.

A. Path Determination:

The attached are the images of the various phases obtained from the vision systemFig :2a) represents how a typical field looks like in general.

Fig: 2a)

The remaining images are the processed images of the main images of the field so thatthe Robot would be able to find the path for its motion.Fig: 2b, 2c, 2d are the images after each stage of processing.


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Fig: 2b)

Fig: 2c)


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Fig: 2d)

From the image obtained from the fig: 2d) we can always try to center the Robotbetween the left extreme and right extreme. So, this is shown as * in the left row andwith in the right row this process is continued till any green pixel is visible on the

image. The center path is depicted with

The center points will let us determine the projected path that the Robot must follow.

Fig: 2e)


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B. Speed Control

The movement of the Robot is controlled by an optical encoder. A digital optical encoderis a device that converts motion into a sequence of digital pulses. By counting a singlebit or by decoding a set of bits, the pulses can be converted to relative or absolute

position measurements. This optical encoder allows to have a speed feedback andhence, construct a speed control loop. The Fig 3 shows the step response of the Robots with response the input voltage

Fig. 3. Step response of Robot, with main propulsion motor voltage as input

B. Path Tracking:

The steering is controlled by two servo motors, which receive a position reference. Thisallows us to construct a navigation algorithm for controlling only the steering angle,since the servomotor will take care of applying the desired angle to the wheels.

A servomotoris a rotary actuator that allows for precise control of angular position,velocity and acceleration. It consists of a suitable motor coupled to a sensor for positionfeedback. It also requires a relatively sophisticated controller.This means that we only have to care about generating the reference for theservomotor. The path generated by the vision system can be used to calculate the

deviation of the road with respect to the straight line. Consider for instance, that thegenerated map is as it is shown on Figure 4. The quantity P is an objective distancespecified by the user. A typical value for P is 1.5[m]. The quantity Q is the horizontaldeviation, produced by movingP meters ahead on the traced path.


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Fig. 4. a)Expected map. b) realistic map, generated by the vision system.

The actual path taken would be more close to the fig 3b) as the terrain would beuneven. This makes it difficult to compute the value of Q, and generates an undesiredoscillatory behavior on the steering angle. The approach for solving this matter is to fit aline to the path, between the origin and the objective distance, just as it is shown onFigure 4b. This is done for every iteration. The horizontal deviation Q is calculatedfrom the fitted line, instead of the original path, with the relation

Q = mP + bwhere m and b are, respectively, the slope and bias of the line fitted to the path.This procedure low-pass filters the path, attenuating the oscillatory behavior of Q.Now let us propose a control law for the steering angle. The speed component on the Qaxis is

VQ = v sin

But for ease of construction purpose we can restrict the between the upper limit andlower limit in general the following process is adopted

[/9, /9]This lets us make the simplification

VQ v

The reference steering angle will be calculated proportional to the desired deviation onthe Q axis (Q). This means


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VQ = KQQ

The parameter KQ is calculated empirically, having a typical value of 5000. Q iscalculated on every iteration, as well as the Robots speed v is read from the encoder.We can say that,

ref = KQQ/v

A distinction should be made to consider the case when v 0, causing refto becomeinfinite. The solution is very simple,the Robot should simply not apply any change tothe steering angle unless the Robots speed ishigh enough. Considering this, a finalexpression for the steering control law is:

ref (k) =

if |v| vmin(KQ)Q(k)/v(k)else

ref (k 1) , otherwise

Hence, we can obtain the following graph


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Reliability

This is most best and suitable mechanism on a rough and uneven terrain because it can

easily move and carry the load along with it. Hence, the efficiency of this kind of a Robot

would be high and suitable for the goal required.

Maintainability

This mechanism has a few problems and need to be taken care. It is fine if the field is

just slightly damp but sometimes it is quite possible that field turns out to be highly wet

and soil doesnt provide enough friction for the Robot to move in such a cases the

Robot may sink into the field and may not be able to move any further then it may need

some manual help by someone to move. Otherwise, the Robot can function completely

autonomously.

REFERENCES

[1] Various Field Robot Event 2005 preceedings. Wageningen, The Netherlands:Farm Technology Group, 2005.

[2] Mario M. Foglia, Giulio Reina,Agricultural Robot for radicchio harvesting.,Journal of Field Robotics. Wiley, 2006.

[3] P.L. Koon, Evaluation of Autonomous Ground Vehicle Skills, masters thesis,tech. report CMU-RI-TR-06-13, Robotics Institute, Carnegie Mellon

University, March, 2006.

[4] Anbal Ollero Baturone, Robotica: Manipuladores y robots moviles.,Barcelona, Spain: Marcombo, 2001.

[5] David T. Cole, Salah Sukkarieh, Ali Haydar Goktogan, System developmentand demonstration of a UAV control architecture for informationgathering missions., Journal of Field Robotics, vol. 23, issue 6-7, pages417440. Wiley, 2006.

[6] Patric Jensfelt, Gunnar Gullstrand, Erik Forell,A mobile Robot system forautomatic floor marking., Journal of Field Robotics, vol. 23, issue 6-7,pages 441459. Wiley, 2006.

[7] Toru Torii, Research in autonomous agriculture vehicles in Japan., Computersand Electronics in Agriculture, Volume 25, Issues 1-2, January2000, Pages 133-153, Elsevier, 2000.[8] R. D. Tillett,A calibration system for vision-guided agricultural robots. Journal of

Agricultural Engineering Research, Volume 42, Issue


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4, April 1989, Pages 267-273, Elsevier, 2000.

[9] Graham C. Goodwin, Stefan F. Graebe, Mario E. Salgado, Control SystemDesign., Prentice Hall, 2001.

[10] Karl Johan Astrom, Bjorn Wittenmark, Computer-Controlled Systems:Theory and Design, 3rd ed. Prentice Hall, 1996


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Pesticide Optimization/Delivery Mechanism

Entity Definition

The system is responsible for optimizing pesticide selection, storage and spraying

mechanism.

Scope

The scope of this sub-system is:

Selecting the optimum pesticide according to various factors - weight, volume,

family of crops etc.

Devise a mechanism to store the pesticide on the robot in cylinders. Devise a mechanism to spray the pesticide.

Make the refilling process (to be done by the farmer) easier.

Pesticides

Pesticides are substances meant for attracting, destroying or mitigating any pest. The

most common use of pesticides is as plant protection products (also known as crop

protection products), which in general protect plants from damaging influences such asweeds, plant diseases or insects. In general, a pesticide is a chemical or biological

agent (such as a virus, bacterium, antimicrobial, or disinfectant) that deters,

incapacitates, kills, or otherwise discourages pests. Target pests can include insects,

plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes (roundworms), and

microbes that destroy property, cause nuisance, or spread disease, or are disease

vectors. Although pesticides have benefits, some also have drawbacks, such as

potential toxicity to humans and other desired species.


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Primary benefits

Improved crop yields

Improved crop quality

Invasive species controlled

Diseases contained geographically

Figure: Cabbage Farm

Domain of crops - Lettuce, Cabbage, Cauliflower, Broccoli

Choosing the best pesticides

Brass ica oleracea - Bras sica oleraceais the species of plant that includes many


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common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels

sprouts, savoy, and Chinese kale. A common class of pesticides can be used for them.

Lettuce- Generally grown as a hardy annual, lettuce is easily cultivated, although it

requires relatively low temperatures to prevent it from flowering quickly. It can beplagued with numerous nutrient deficiencies, as well as insect and mammal pests and

fungal and bacterial diseases. L. sativacrosses easily within the species and with some

other species within the Lactucagenus.

Lettuce belongs to the family Asteraceae has slightly different properties and so some

variation in usage pattern is visible in the following study:

Pesticides for cabbage, cauliflower and broccoli:

Insect Pest Cabbage Cauliflower Broccoli

Aphids insecticidalsoap

neem oil extract

pyrethrin

acetamiprid

permethrinbifenthrin

cyhalothrin

Imidacloprid

insecticidalsoap

neem oilextract

pyrethrin

acetamiprid

permethrin

bifenthrin

cyhalothrin

Imidacloprid

insecticidal soap

neem oil extract

pyrethrin

acetamiprid

permethrin

bifenthrin

cyhalothrin

Imidacloprid

Caterpillars Bacillusthuringiensis(B.t.)

spinosadpyrethrin

carbaryl

acetamiprid

permethrin

Bacillusthuringiensis(B.t.)

spinosadpyrethrin

carbaryl

acetamiprid

permethrin

Bacillus thuringiensis(B.t.)

spinosad

pyrethrin

carbaryl

acetamiprid

permethrin

bifenthrin


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bifenthrin

cyfluthrin

bifenthrin

cyfluthrin

cyfluthrin

Harlequin Bugs &Stink Bugs

permethrin

bifenthrincyfluthrin

Imidacloprid

permethrin


Imidacloprid

permethrin


Imidacloprid

Flea Beetles neem oil extract

carbaryl

acetamiprid

permethrin


cyhalothrin

neem oilextract

carbaryl

acetamiprid

permethrin

bifenthrin

cyfluthrin

cyhalothrin

neem oil extract

carbaryl

acetamiprid

permethrin


cyhalothrin

Whiteflies insecticidalsoap

neem oil extract

pyrethrin

cyfluthrin

bifenthrin

cyhalothrin

insecticidalsoap

neem oilextract

pyrethrin

cyfluthrin

bifenthrin

cyhalothrin

insecticidal soap

neem oil extract

pyrethrin

cyfluthrin

bifenthrin

cyhalothrin

Pesticides for lettuce:

Imidacloprid

DCPA

Permethrin

Acetamiprid


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Dimethomorph

Usage pattern:

Cabbage, cauliflower and broccoli:

Pesticide Gross Pounds Acres Treated Application Rate

(Pounds per acretreated)

cyhalothrin 2,601 92,247 0.03

neem oil extract 3,637 1,231 2.96

permethrin 396.4 2,163 0.18

bifenthrin 176.3 819.0 0.22

Imidacloprid 895.4 6,737 0.13

Lettuce:

Pesticide Gross Pounds Acres Treated Application Rate

(Pounds per acretreated)

Imidaclorid 10,973 85,695 0.13

permethrin 13,898 81,729 0.17

Best pesticide for the domain of crops - Imidacloprid, permethrin

Storage

Tank - These should be made of stainless steel or fiberglass. If the tank is made of mild


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steel, it should have a protective lining or coating. The tank should have a large opening

for easy filling and cleaning and a large drain. It should allow straining during filling and

provide for mechanical or hydraulic agitation. All outlets should be sized to the pump

capacity. All tanks should have a gauge to show liquid level and a shutoff valve.7.5 to 8

litres of water tank would be suitable for the robot. Keep tanks clean and free of rust,

scale, dirt, and other contaminants which can damage the pump and nozzles of thesprayer.

Amount of mixture(in litres)

Weight of pesticideto be added (ingrams and pounds)

Area of land covered (in acres)

1 4.706 g or 0.01

pounds

permethrin - 0.055

Imidaclorid - 0.077

7.5 - 8 35.295 - 37.648 gor 0.078 - 0.083pounds

permethrin - 0.43 - 0.52

Imidaclorid - 0.6 - 0.7

Spray rate

Spray volume per acre for permethrin18.18

Spray volume per acre for imidaclorid13

Spraying the Pesticides

General Practice

Human worker would walk down the field with a pesticide spraying gun, in an attempt to

cover the foliage of the plants with an even coat of spray. An experienced worker

will attempt to coat the surface of the plants with the appropriate calculated dosage.

This manual application of pesticides is, as mentioned above, a time consuming,

tedious and dangerous task, requiring the worker to wear protective clothing and

breathing apparatus. Hence, this manual application technique is largely open for error.


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Parts of Sprayer

Pump

The most commonly used pumps are roller, piston, and centrifugal pumps. Its a good

idea to choose a slightly oversized pump. This ensures that the relief valve will operate

and also that, even with wear and tear, the pump will still do the job. The pump is

turned on and off based on the instructions from the sensors.

Hose

Select neoprene, rubber, or plastic hose.

Specifications of the hose are:

Have burst strength greater than peak operating pressure.

Have a working pressure at least equal to the maximum operating pressure.

Resist abrasive or corrosive effects of oil, solvents and pesticide product and

formulations used. Are weather resistant.

Figure: Guide for determining the Hose size.


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Because the plants selected are Lettuce, Cabbage, Strawberry, Cauliflower, Broccoli

the average Pump Output is under 12 GPM so the inside diameter of Suction hose is

3/4 and Discharge Hose is 5/8.

Nozzle

The nozzle is a critical part of any sprayer. Nozzles perform three functions:

Regulate flow

Atomize the mixture into droplets

Disperse the spray in a desirable pattern.

We will have a replacable nozzle to the pump of the sprayer.The figure shown below is

the guide for Nozzle selection.

Figure: Nozzle guide for spraying.

Permethrin is aninsecticide.

Pressure Regulator

The pressure regulator controls the pressure in the system. This protects sprayer parts

from damage due to excess pressure. The pressure range and flow capacity of the

regulator must match the pressure range you plan to use and the capacity of the pump.


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The bypass line from the pressure regulator to the tank should be kept fully open and

unrestricted and should be large enough to carry the total pump output with excess

pressure buildup. Thepressure regulator regulates the pressure required by taking

instruction from the Bot.

Pressure needed for spraying:

The type of pesticide and nozzle being used usually determine the pressure needed for

spraying. This pressure is usually listed on the chemical package.

Low pressures of 15 to 40 PSI may be sufficient for spraying most herbicides or

fertilizer, but high pressures up to 400 PSI or more may be needed for spraying

insecticides or fungicides.Here the pressure is 15-40 PSI.

Pressure Gauge

Every sprayer system needs a pressure gaugeto tell you how much pressure is being

used. The gauge will indicate any failures in the sprayer by showing changes in

pressure. Use a gauge designed for the pressure range of the sprayer. A high-pressure

gauge will not give an accurate reading of a low-pressure sprayer. Thisis usefulwhen the

farmer wants to check the pressure applied.

Agitator

Many spray mixtures must be agitated (stirred up) to keep the pesticide and carrier

mixed. For most mixtures, the liquid returning from the regulator bypass line provides

enough agitation. But additional agitation is needed for wettable powders to keep them

in suspension. This can be done by using paddles in the tank to stir up the mixture. Ajet

agitator uses a nozzle inside the tank. The nozzle continuously sprays some of the

spray mixture in the tank to keep it stirred. The line to thejet agitatoris connectedbetween the pump and the shutoff valves to the nozzles. In this way, when spraying is

stopped for a few minutes, the agitation will continue inside the tank.


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Strainers

Strainers, also called screens, are used to catch anything that could damage or clog the

system. There are four places where strainers are used. Each one requires a different

size strainer.

1.At the entrance to the pump intake hose, 25 to 50 mesh screen.

2.In the line from the pressure regulator to the boom, 50 to 100 mesh screen.

3.In each nozzle.

4.For wettable powders, all screens should be 50-mesh or coarser.

Choosing the method of Application of Pesticides

Different application methodsare appropriate for different crop and pest types, but the

method of application should always be consistent with the label directions.

Application methods include:

Band application: Applying a pesticide in parallel strips or bands, suchas

between rows of crops rather than uniformly over the entire field.


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Figure:Sprayer

Basal application: Directs herbicides to the lower portions of brush or

small trees to control vegetation.

Broadcast application: It is the uniform application of a pesticide to an

entire area or field.

Directed-spray application: It specifically targets the pests to minimize

pesticide contact with non-target plants and animals.

Foliar application:It directs pesticide to the leafy portions of a plant.

Spot treatment: It is the application of a pesticide to small, distinct areas.

In this case the application used is Band Application.By taking the input from other

subsystems about the pressure and the area to be treated of pesticide the sprayer acts

accordingly.

References

http://www.pesticideinfo.org/

http://www.whatsonmyfood.org/

http://www.clemson.edu/extension/hgic/pests/plant_pests/veg_fruit/hgic2203.html

en.wikipedia.org/wiki/Pesticide

http://www.ext.colostate.edu/pubs/garden/07615.html


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System Integration

Scope

System integration is defined as the process of bringing together the

component subsystems into one system and ensuring that the subsystems functiontogether as a system. A system is an aggregation of subsystems cooperating so that

the system is able to deliver the overarching functionality. System integration involves

integrating existing often disparate systems.

System integration (SI) is also about adding value to the system, capabilities that are

possible because of interactions between subsystems

Method of Integration:

The robot is designed to be an autonomous ground robot that is capable of identifying

crop damage and administering pesticide when necessary.

A legged mode of locomotion has been chosen since this provides more flexibility in

terms of motion. The legs are controlled via servo motors and are connected to the

main body of the robot. A force feedback mechanism is mounted on the legs through

the use of pressure sensors. These help the robot identify the kind of terrain it is moving

on and adjust its motion accordingly. Also, the legs have temperature and moisture

sensors for checking soil conditions. This provides information to the control unit which

then decides its actions accordingly.

The body of the robot consists of a control unit and a pesticide payload. It also serves

as the base for the robotic arm. The robot will have 6 six legs over which there will be

the tank which will store the pesticide/insecticide. Over that will be the battery and

above that will be the attached robotic arm. The control unit is the decision making

entity for the entire system. It takes decisions based on the inputs given to it by the

camera and other external sensors. For example, if through the camera, it detects a

particular disease in the plant, it sprays pesticide on the affected area. The robot will

use a 60V1.5Ah battery.

The arm has 3 joints, the first of which is mounted on the body of the robot. The other 2

joints provide additional flexibility to the arm thereby improving its pesticide delivery

mechanism. A pipe connected to the pesticide tank runs along the arm serving as the

method of delivery. It also has a feedback mechanism to the control unit in case offailure.

The overall design is ergonomical and is easy for farmers to use since they only need to

decide the type of pesticide being used and refill the tank when it is running low.


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Different Subsystem Interaction:-

Different Subsystems involved in the process of integration are:-

Pesticide Delivery

Robotic Arm

Decision planning

Motion Planning

Other sensors

Given below is a detailed version of interaction:

1. Pesticide Delivery with Decision Making: - Pesticide Delivery subsystem will be

responsible for giving input to the decision subsystem such as - rate of pesticide

delivery, amount of pesticide remaining at any moment etc. After taking inputsfrom the pesticide delivery subsystem, the decision making unit processes these

inputs and the rate of delivery is changed accordingly if needed. Moreover, a

warning will be given to the farmer to refill the pesticide if its below a certain

level.

2. Pesticide Delivery with the Robotic Arm: - Pesticide, water will be sprinkled by

the robotic arm. It also has a feedback mechanism in case of failure.

3. Robotic Arm with Decision Making: - The robotic arm provides a visual input for

surveying the surroundings through a mounted camera. Data gathered is

processed by the control unit and is used to decide further actions. The arm also

serves as a medium through which the pesticide is delivered.

4. Motion Planning & Locomotion with Decision Making: - This entity is concerned

with controlling the motion of the robot along the ground and ensures its

movement prevents damage to the robot and the crops around it.

5. Other sensors: - These include other sensor inputs such as a force feedback

mechanism, camera, temperature sensor, etc. These interact with the central

decision making unit to help aid the decision making process.


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A rough overview of interaction of different subsystem can be seen by the underlying

diagram.

System Interaction Diagram

Decision

Making

Robotic

Arm

Other Sensors

Pesticide

Delivery

System

Motion

Planning &

Locomotion

Commands

Visual Display

(via mounted

camera)

Odometry

Higher

OrderCommands

Commands

FeedbackInformation

Farmer Interface

(Decides type of pesticide and

amount to be used)


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Complete System Interaction

The decision making system is responsible for taking all the decisions according to thefeedback received by it. This is where the processor of the robot sits which isresponsible for making all the major computations required to run the robot. The

processor is completely programmable making the Robot extremely flexible enabling itto work on any crop and any kind of terrain. The pesticide delivery system measures thevarious aspects such as weight and the pressure inside the pesticide tank and sendsthe feedback to the decision making system regarding the pesticide control such as rateof pesticide flow, amount of pesticides required etc. The decision making systemprocesses the signal and sends commands to other parts accordingly. In case thepesticides need to be refilled, a warning is sent to the farmer. A robotic arm is attachedto the pesticide delivery system which sprinkles water, pesticides and other componentsthat are required for the plant. A feedback mechanism is attached to the robotic arm incase of failure. A mounted camera is attached to the arm which takes visual input fromthe surroundings and sends the data to the control unit where further processing takes

place and commands to various parts are sent accordingly. Motion planning andlocomotion system plays an important role in the subsystem. It takes care of themovement of the robot along the field ensuring no damage is caused to plants and theRobot. Other sensors such as infrared sensors, temperature sensors etc. sends theinputs to the control unit for further actions.


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Case Study

Lettuce Bot is just one of many robots intended to automate aspects of agriculture and

horticulture that are still highly labor-intensive, even in the rich world. The bot initially is

targeting organic farming since Organic farmers do not use herbicides to kill

weeds.The battery-powered system crunches the images fast enough to work at 98%

accuracy while chugging along at a bit less than 2kph. The battery-powered systemcrunches the images fast enough to work at 98% accuracy while chugging along at a bit

less than 2kph.

When a plant is identified as a weedor as a lettuce head that is growing too close toanother onea nozzle at the back of the unit squirts out a concentrated dose offertilizer. This sounds bonkers, but it turns out that fertilizer can be as deadly as apesticide, which is why farmers usually sprinkle it at a safe distance of 10-15cm fromthe plants to be nourished, so as to dilute its effect. So the robot not only kills weedsand excess heads, but feeds the remaining crops at the same time.

The bot currently only works on Iceberg and Romaine lettuces, as the database of

stored images was generated for those plants only. Switching to another vegetable will

involves building another database to compare images against.

Methods are being employed to enhance Lettuce Bot by expanding the weeds it can

identify and the fields in can operate within. Though the organic community may be anti-

GMO, it certainly would embrace a technology that would allow it to minimize or even


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eliminate the use of herbicides, even one as high tech as a robot. But the robot is not

limited to organic farming either, as herbicide-resistant weeds are a widespread

problem. Down the road, a robot working a field could do more than just visually

recognize weeds. It could also catalog insects it observes and identify pests.

Functionality could be expanded to include testing of soil pH, nitrogen levels, and water

content.

Documents

Preliminary Design Review of Robot for Agriculture Automation