Design and Development of Autonomous Lawn Mower
The purpose of this project is to develop and design an autonomous lawn mower mobile robot. This robot will mow the grass from a field or a playground autonomously. In past, it contained heavy machinery which required more man power while now its machinery is reduced to a small size and it requires
2025-06-28 16:31:21 - Adil Khan
Design and Development of Autonomous Lawn Mower
Project Area of Specialization Mechanical EngineeringProject SummaryThe purpose of this project is to develop and design an autonomous lawn mower mobile robot. This robot will mow the grass from a field or a playground autonomously. In past, it contained heavy machinery which required more man power while now its machinery is reduced to a small size and it requires less man power. The robot basically consists of three major components navigation control, sensory system and grass mowing mechanism. This robot works in unstructured, dynamic and unknown environment. Motor schema architecture is being used along with continuous response encoding and cooperative coordination for behavior coordination. With the help of sensors, microcontroller is utilized to monitor every action of lawn mower. Through an array of sensors, this robot will not only stay on the lawn, as well as it will avoid and detect objects and humans. It detects the land boundaries and start mowing with the help of installed camera.
Project ObjectivesThe objectives of this project are to
- Design an Autonomous lawn mower
- To save energy and time in lawn mowing using the self-operated mower.
- Develop a cost-effective mower by keeping in view the small farmer/house hold.
The project will be implemented as follows
- First of all we will do CAD modeling using solid works.
- After CAD design it will be finalized for product development.
- We will select material such as(motor,tires,battery etc).
- Assembling the mechanical components.
- Then the automation work will be done for it's self operating.
- Autonomous lawn mower will be tested on field for finalization.
Benefits of the Project will be
- It can avoid crossing points repeatedly to save time.
- It works on its own. No user interference is required.
- Robot is able to move without any information about environment.
- It performs mowing which is boring and difficult to perform in sunny conditions by humans.
- It avoids the danger of mowing blades to the humans.
- It uses renewable energy instead of fuel which means its operation only requires maintenance cost that can be negligible in its case.
- This robot is a step forward towards agricultural robotics as well as unmanned ground vehicles i.e. vacuum cleaner robot, bomb detection etc.
Technical Details
The autonomous lawn mower consists of three major components, navigation control, sensory system, and grass mowing mechanism.
1. Mechanical Structure of Lawn Mower:
The structure of a lawn mower consists of the following parts:
- Main Frame
- Tires
- Gearbox
- Shafts
Main Frame:
The mainframe of the lawnmower is made up of cast iron. It is round from the back and rectangular from the front width of N/A and length.
Tires:
It has three tires, two on the front and one on the back. The tire on the back is the caster wheel. The two tires on the front. These tires will change the direction of the Lawnmower. These tires are directly connected to shaft.
Shaft:
The shaft is made up of polished steel. It’s diameter is of 20mm, and length is not defined yet. The shaft is connected to gear box.
Gear box:
The gear box consists of four gears with ratio 60:15:60:15. It will reduce the speed of our motor from 3000rpm to 300rpm. One gear is connected to motor and other is connected to shaft and the other two are compounded together. It is made up of very heavy metal.
Motor driver:
When we have to drive a DC motor in only one direction (forward or backward) we do not need any additional circuity until we have to change its speed. Motor control is the heart of robotics because without motion robot is dead and no robot has to move in just on direction also.
Motor driver is used for four quadrant control of motor i.e. forward, backward and break with full speed control up to 32 KHz frequency provided by PWM via Arduino. Main purpose is to design a 10amp controller that can be used to drive a DC motor in both directions as well as to control its speed. It works on the principle of H-Bridge which is true concept for controlling a DC motor. H-Bridge are available in market in form of ICs for controlling DC motor up to 2amp while in our project motor used, consume 10amp on full load. Initially it sounds like a difficult task because transistor rating is not such more to bear such a load..
Othe Equipments used:
TIP 147 Transistor, TIP 142 Transistor , 2n222 Transistor, Resistors (10K and 1K), Opto-coupler,Terminal block (dual and triple)
TIP142 is a NPN transistor while TIP147 is a PNP transistor. They are fit together for the HBridge scheme. Here they are used for switching purpose during the current flow up to 15amp. 2n222 transistors are NPN BJT transistors used as buffer b/w controller and control side of the motor. A simple digital signal in 2n222 tells the motor to move in which direction. Dual terminal block is used for the power, motor connections and digital signal inputs. While triple terminal blocks are used for the insertion of transistors instead of direct soldering so they can be placed easily in case of damage. When photodiode side of opto-coupler is turn ON it emits light which turns the phototransistor ON and power starts to flow from collector to emitter in transistor.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 79500 | |||
| DC Motor | Equipment | 5 | 5000 | 25000 |
| Frame | Equipment | 1 | 6000 | 6000 |
| Tires | Equipment | 3 | 2500 | 7500 |
| Gear | Equipment | 6 | 1000 | 6000 |
| Shaft | Equipment | 1 | 3000 | 3000 |
| Battery | Equipment | 1 | 7000 | 7000 |
| Cutting blades | Equipment | 3 | 1000 | 3000 |
| Other components | Miscellaneous | 1 | 10000 | 10000 |
| Electrical Circuit, Transistors, Controllers | Equipment | 1 | 12000 | 12000 |