The aim of this project is to implement Simultaneous Localization and Mapping (SLAM) with Quadcopter in indoor environments. While realizing this project, we will face some problems to be solved. Figure – 1 describes the overall system problem statements and constraints as a flow chart.
Figure – 1 Problem Statement Chart
Before starting connecting parts and coding, we needed a simulation environment to observe the dynamics of the Quadcopter and the data flow from laser range finder unit. There are various tutorials and examples about this subject. Most of these works are implemented on ROS (Robot Operating System) environment using Gazebo or Rviz.
Simulation process involves several problems as follows:
An indoor environment and should be created.
A Quadcopter and sensing unit model implementation.
Data flow from simulation environment should be extracted and processed. Visual observation of SLAM
Simulation process is very important and the beginning process of our project to understand the behaviors of a Quadcopter and sensor unit and how to deal with them while realizing SLAM in indoor environments.
2. Hardware Selection and Assembly
In that part of project includes mean elements of our work. Basically, we design a system which is flying and carrying some sensors on it for simultaneous localization and mapping (SLAM). We must put all elements on our frame and every piece has a weight and size. According to our researches, a Quadcopter requires motors, propellers, electronic speed controllers (ESC) for motors, battery and a flight control board. In order to implement SLAM with a Quadcopter, we also need a sensing unit and a single board computer to process sensor data and to communicate with local station. Figure – 2 shows the general Quadcopter structure that we are planning to construct.
Figure – 2 Quadcopter Structure
3. Flight Test
Before the Quadcopter could be tested in free flight, it had to be determined that it would not respond in a way which would damage itself.
3.1. Take Off
We need to first take-off our Quadcopter from the ground safely, but before that some tests should be applied. This tests involve mechanic parts and electronic parts.
Mechanical test contains:
Dimension parts, assembly verification, throttle control test, motor alignment, counterclockwise operation of engine, clockwise operation of engine, propeller balancing, Quadcopter balancing, wake interaction, vibration analysis, thrust and rotor check.
Electronic test contains:
Battery connection and test, motor and speed controller (ESC) test, flight control board calibration.
The main problem in Quadcopter is the balancing and stability while it's flying. Most of Quadcopters will be unbalance and lost stability in case there are disturbance direct on it such as wind or have overweight problems. Our project will be examined at indoor environments. So, there won't be any wind in our test environment. However, we will face with some stability problems because of weight, construction, design, and big motors. Mostly, batteries cause weight problem on quadcopters.
We will have multiple inputs and multiple outputs on our Quadcopter. Therefore, our Quadcopter absorbs more energy. To test a fully equipped Quadcopter productively, supply will be sufficient to overcome, and will be durable for more than 10 minutes.
After flying section, we face another problem, landing. The landing procedure can also be broken down into three steps: moving into horizontal position, orienting the direction the Quadcopter is facing and decreasing altitude while maintaining orientation and location until the surface has been reached. It causes another problem that control by autonomous or control by a remote control switch.
4. Localization and Navigation
Localization and map building in our project are key components in robot navigation are...
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