SEEDS SOWING ROBOT

According to Food and Agriculture Organization of the United Nations, world’s population is expected to grow to almost 10 billion by 2050, boosting agricultural demand. This implies an urgent need to automate the Agricultural sector to gain in productivity and effeciency.

From above mentioned, the project of building a Seed Sowing Robot as a solution to agricultural constrains was put in place. The aim of this project is complety automate sowing of seeds by eliminating human labor and increasing production..

This Instructable aims to guide you through the process of creating a seed sowing robot. Project was designed and engineered as part of our Bruface Mechatronics project and has been realized by:

- Ahmad Nasrallah

- Federico Lucca

- Alessandro lupi

- Abbas Lakkis

- Christian Kamguia

- Francesco Fuochi

- Ali Moallem

Step 1: FULL 3D ASSEMBLY

Step 2: LIST OF PARTS

Step 3: ELECTRONIC PARTS DESCRIPTION

Step 4: LASER CUT PARTS

Step 5: 3D PRINTED PARTS

Step 6: TESTING AND TUNNING OF ELECTRONIC PARTS

Step 7: CIRCUIT ASSEMBLY

Step 8: FLOW CHART

Step 9: CODE USED TO RUN OUR ROBOT

Here we have made a full 3D assembly of the robot and we mainly focused on the mechanical part that includes the Main frames, tracking gears, the dispenser and the plough. CLICK HERE TO DOWNLOAD

Below are the lists of parts used do build our robot:

1) Electronic Parts:

- Arduino Uno (Quantity 1)

- Breadboard ( Quantity 1)

- Servo motor SKU#HK15138 (Quantity 1)

- Ultrasonic sensor HC-SR04 (Quantity 1)

- DC motor with encoder (Quantity 2) [Link]

- DC motos supports (Quantity 1) [Link]

- Motor driver L298N (Quantity 1)

- Bluetooth device HC-06 (Quantity 1)

- Power source 06 V (Quantity 2)

- Connecting wires

- Tracking system [Link]

2) 3D printed parts

- Funnel

- Relover

- Revolver frame

- Plough

- Racks gear support

3) Laser cut parts

- Dispenser case

- Base Case

- Screws and Nuts

- Mdf ticknesses are 4mm and 6mm (for thoughness and stability of the robot )

Here we give the main function of each electronic part used to operate the robot

- Arduino Uno: This is a microcontroller board with 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button.

- Breadboard: thin plastic board used to hold electronic components.

- Servo motor SKU#HK15138: is a closed-loop servomechanism that uses position feedback to control its motion and final position.

- Ultrasonic sensor HC-SR04: Used to measure distance, It generates high frequency sound and calculate the time interval between the sending of signal and the receiving of echo.

- Encoder built in dc motor: Used to Drive the Tracks and connected to the gears throup a coupling part. Its rotary incremental encoder has two output signals, A and B, which issue square waves in quadrature when the encoder shaft rotates. The square wave frequency indicates the speed of shaft rotation, whereas the A-B phase relationship indicates the direction of rotation.

- Motor driver L298N : is a dual H-Bridge motor driver which allows speed and direction control of two DC motors at the same time.

- Bluetooth device HC-06: Bluetooth module designed for wireless serial communication and it is paired to a master Bluetooth device such as PC, smart phones and tablet.

- Power supply 12 Volts: Used to run our robot

- Connecting wires: Used to establish interaction between Adruino uno and all the electronic components included in our design.

In this section it should be noted the entire body / frame of the robot is made MDF of 6mm and 4mm tickness. All these parts where designed in Solidworks and cut using a BRM Laser Machine.

- Dispenser casing: This casing is needed to hold the dispensing mechanism in place and equally adjust the positioning of the revolver, the servo motor and the funnel in the mounting process.

- Base casing: This is used as embodiment for the tracking mechanism made of gears and motor. It also holds all the electronic components with embedded codes. The Base casing holds the 3D printed plough.

- Screws and nuts: For robustness and stability the entire body holds a total of 60 available screws and nuts.

Few parts were 3D printed due to mainly due their shape and application in the robot. these parts are mainly

- Funnel : Used as seed collector, it holds the seed and its inlet is directly connected to the inlet of the revolver

- Revolver : Located under the dispenser, it has two types of seeds holder a small and medium size holes. It rotates in a periodic way when actuated by the servo motor. It is connected to the servo motor through a coupling shape embedded in the Solidworks design.

- Revolver frame: This part ensures the seed are maintain in the revolver seed hold and dropped after prescribed angular rotation of the revolver.

- Plough : Located under the base casing, digs the exact in the soil before the seeds are dropped by the dispensing unit.

- Racks gear support: This parts hold the rotation axis of the tracks in other to insure steady rotation of the gears.

click here to download the step.file

Critical parts were tested and tunned to meet prescribed output:

1 - Ultra sonic sensor was tested and tunned to detect any obstacle and stop the robot.

2 - Servo Motor was Tested and tunned to dispense the seed at prescribed offset distances.

3 - Dc Motors where tested and tunned in other to provide prescribed rotation for offset and total distances to be covered.

4 - Bluetooth application was tested in pairing process between the Mobile device and the robot.

Above are schematics of the different controllers used for the main electronic parts:

- Full Circuit schematic

- DC Motor Controller.

- Servo Motor Controller.

- Ultrasonic Controller.

- Bluetooth Controller.

Abbreviations used:

- Offset distance (od): Distance between two seed sowed.

- Total distance (td): Distance to be cover by the robot to sow the seeds.

- Dispensing Motor (md): Servo motor dispensing the seeds at set moved distance.

Click here to download code used to control the following modules :

- Bluetooth module

- DC Motor + Encoder module

- Servo Motor module

- Ultrasonic sensor module

In Conclusion, the robot operated globally speaking. To operate the robot we need to adjust the revolver according to the size of the seeds that would be used. Therefore, for big seeds ( 1cm and above) we use the big holes and f or small seeds (less than 1cm) we use the small hole. Also, the bluetooth mobile application is paired with the robot and the total distance and offset distance are set before pressing the start button.

Although the robot seem to operate properly, some major improvements were identified during the testing phase and need to be addressed in future.

These problems are mainly:

- Deviation of the robot : Here the robot is deviated from the linear trajectory after moving over a certain distance. As a solution a compass sensor can be used to adjust this deviation with a maximum error of 5 degrees deviation from ref linear trajectory.

- Poor plough design and material property: The plough design is not suited for high torque, since the design of the attachment to the base plate of the robot wouldn't withstand higher torques also the plough made of plastic can not be used harder soils. As a solution a suitable design should be considered and tested. Lastly, a stiffer material should be used like steel, to adapt to any type of soils.

- Seed staking: It was observed that the seeds get stacked between the revolver and the bottom neck of the funnel, stopping the dispensing process. As a solution, the cylindrical bottom neck of the funnel should be removed in the design, allowing the seed to be fed directly in the revolver dispensing the seeds.