Solar Powered Autonomous Lawn Mower

Lawn mowing is considered to be one of the most boring and tiring routine household tasks, but mowing the lawn is a very important part of proper yard care and the properly cut lawn is something that is very pleasant to behold which gives the lawn an orderly appearance. An idea to design an Autonomo

Project Title

Solar Powered Autonomous Lawn Mower

Project Area of Specialization

Robotics

Project Summary

Lawn mowing is considered to be one of the most boring and tiring routine household tasks, but mowing the lawn is a very important part of proper yard care and the properly cut lawn is something that is very pleasant to behold which gives the lawn an orderly appearance. An idea to design an Autonomous Robotic Solar Powered Lawn Mower (ALM) is proposed in this document. Like in every other product, the price-performance ratio is the most significant evaluation metric for a consumer while buying an autonomous robotic cleaner or an autonomous lawn mower (ALM). The "performance" in this context, mainly denotes the navigation success of the robot. Our project aims at easing the lawn mowing experience. We aim at making a lawn mower which is environmental friendly as well as user-friendly and automatic. The lawn mowing job with a motor powered lawnmower is an inconvenience, it becomes difficult for the disabled and elderly people to cut the grass with the help of these mowers. The main focus was to design a prototype that is able to work with a little or no user interaction. Every action of the lawn mower is monitored by the microcontroller with the help of the sensor. Unlike other robotic lawn mowers on the market, this design requires no perimeter wires to maintain the robot within the lawn. The proposed design mows the lawn within the defined area by avoiding hurdles in its path. The system uses Bluetooth control design at the stage one of the projects while at the second stage of a fully autonomous system, wheel odometry to count the motor rotations according to the length and width of the lawn. This path is followed by the system autonomously.

Project Objectives

This project is suitable for a layman as it has many advantages i.e., no fuel cost, no pollution, no fuel residue, and less wear and tear. This provides less physical exercise to the people and can be easily handled. As we are nearer to the Equator, the solar energy is vastly available so it’s very easy to charge the battery. The goal of our prototype is to reduce end user work through the utilization of an easy-to-use device. Following are the objectives of the concerned project that will be mainly focused on the development of the project.

• To extend the design and compatibility of currently used field mowers.
• To design the project so that it will easy to use.
• To detect obstacles that enable the safety of our prototype as well as the surroundings.
• To make the prototype environmentally friendly as the only resource they need is electricity which is stored in their batteries.

Project Implementation Method

Making a lawnmower autonomous isn’t an easy task. There are many steps involved which constitute testing of components, designing a framework for the project, literature review, and assembly of the project. First, the team decided to test all the components required and calculate the parameter of the required project. Testing was done manually while the calculations were performed keeping in view the requirements. For the accurate methods of testing and deductions, we read several sources and research paper. The next task was to design a frame and to make that happen, one of the team members drew the structure and dimensions of the desired frame and designed the project body manually on paper which served for the purpose. Then motors and blades were mounted while drives and controllers were also installed. Further, we moved to the software area of the project and calculations and the final testing was done on the prototype. We divided the chores of the project n steps and tried to accomplish one at a time. Our main concern was to complete the project within the span specified by the department.

Following steps were considered during the design of the prototype.

• Drive and Blade Motor and Encoder Testing

• Mechanical Structure and Mount Circuit on Mechanical Structure

• Control of Motors using Microcontroller and Motor Drivers

• Obstacle Avoidance using Sonar Sensors

• Wheel Odometer and Source Code

Improvements and Alternative Localization Approaches

Benefits of the Project

It is intended to prepare a prototype of the lawn mower which satisfies the requirements of the customers. Simple and attractive design with good performance should be the primary objective while designing a lawn mower. Keeping in mind all of these customer requirements, all of the calculations of mechanical design has been successfully done. These calculations were helpful while designing and preparing the mechanical structure of the mower. The system has two wheels actuated which are attached to the motors and two freewheels. The whole system with both the hardware as well as the software development has been designed. 

The attractive look, safe system and good path planning technique are considered to be the main objective of this study. A very simple path planning technique is selected which counts the revolutions of the motor, stores the map and follow the stored map autonomously, wheel odometry is the technique used for localizing and driving the vehicle. 

Costly hardware equipment is not used so that the total cost of the system can be reduced to some extent. The cheap equipment like SONAR sensors are used and it is observed that their results are very close to the requirements of the customer. Indoor and outdoor testing with different stages has been successfully done. 

Slippage problem is the major cause of poor mowing performance for the ALMs. To overcome this problem, rubber wheels are used so that the maximum friction between the ground and the wheels can be produced to reduce the slippage factor. This will be helpful in reducing the slippage problem to a great extent. ALMs with very low slippage factor are usually more accurate and efficient as compared to the conventional ALMs.

After the development of mechanical, electrical and software subsystems, indoor and outdoor tests are performed with the different coverage patterns. Their results are observed and compared to observe the overall efficiency of the system. The coverage performance of this prototype is more than 75% for mowing in a parallel path. ALMs having coverage performance above this threshold are considered as the more accurate and efficient. From the different testing scenarios, it can be summarized that the proposed design has a capability to mow with better efficiency.

Technical Details of Final Deliverable

The solar grass cutter has panels mounted in an arrangement at an angle in such a way that it can receive solar radiation with high intensity easily from the sun. These solar panels convert solar energy into electrical energy. This machine consists of the photovoltaic, dc to dc converter, motor, controller, linear blades, and battery. It is an automated system for the purpose of grass cutting. Solar Grass Cutter uses solar power as an energy source that addresses a number of issues that standard internal combustion engine mowers do not. An electric grass cutter with a solar charger will be easier to use. 

The method is as follows:

1. An Arduino Uno control board will act as a processing unit and direct the entire working of the mower as per a presented program.

2. The motion of the mower is controlled by two DC motors of 150 rpm.

3. A height adjustment rack and pinion mechanism have been incorporated to the cutter motor to enable different heights of cut.

4. A Solar panel will charge the battery and eventually power three motors, two of which are for the motion of the mower and the other one are of the cutter blade and height adjustment mechanism of the cutter.

5. Ultrasonic Sensors are used to detect and avoid obstacles

The system uses the Bluetooth module that will be connected to the user’s mobile phone and this module will help the user communicate with the ALM. The Bluetooth module once receives the signal from the user, sends the respective commands to the microcontroller which in return controls the drive wheels of the system. Sonar sensors will be attached for the purpose of hurdle avoidance and once the app sends the signal to move the robot, sonar sensors will be active. A robot can be moved forward, backward, left, right and can be stopped using the mobile app which is designed by the team. Blades of the ALM are attached to the relay sub-system and thus once the relay signals the blade, it will be turned on and when the mowing task is accomplished the blade will be turned off.

Mobile App: Mobile app is designed in such a way that a user can shift the control from Bluetooth one to the autonomous one using just a single button which translates for the user convenience. The user-friendly design was desired and thus careful considerations are kept in mind while designing the app. This Mobile is available for Android users. As mobile phones are quite common these days, and almost every person has a mobile of their own. Thus instead of making a remote controlled version of ALM which will be complex, costly and difficult for a layman to operate, proposed design work on a simple app which comprises of buttons for the forward, backward, left and right commands. If the user wants to operate the ALM personally then he can use the app for the Bluetooth controlled version of ALM, otherwise by just using a single button he can shift to the autonomous control of ALM and thus the robot will be capable of driving on its own and making decisions itself.

Final Deliverable of the Project

Hardware System

Type of Industry

Education , Agriculture

Technologies

Robotics

Sustainable Development Goals

Affordable and Clean Energy, Decent Work and Economic Growth, Industry, Innovation and Infrastructure, Responsible Consumption and Production, Climate Action

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com