building quadcopter (developement)

The assembly process is done in an open space with available power source. All the tools required are prepared along together with the quad copter hardware. Basically the most important tool is a screwdriver with interchangeable head shape. This is to all securing screws of different shapes and sizes. Secondly a solder iron and its iron lead are used to secure certain cables with compatible connectors.

           The first installation process involves putting the frame together. The frame must be assembled accordingly to allow strategic placement of the electronic hardware.

The base of the frame is assembled while having the aluminium pillars arrange with the same colour side by side. This is to determine the front and the back side of the quad copter. Most of the parts are secured with screws and it is made sure that these screws are properly locked in to ensure secure assembly of the frame.

A frame with long landing gear is chosen to protect the hardware from damage if a rough landing were to happen. The aluminium pillars are identified to be long enough to fit 11 inch propellers that are going to be used. This is to avoid unwanted clashing between the propeller blades and other hardware.

A camera adapter is also available on the front side of the quad copter. This camera adapter allows easy and strategic installation of a wireless camera. If not required this camera adapter can be unattached to the frame rather easily.

            Some soldering needs to be done to fix suitable connectors to the lipo battery cables. These connectors will match the power harness. 

A power harness unit is installed at the middle of the base and is responsible to distribute power to all of the quad copter hardware. The power harness will be connected directly to the 14.8 volt lipo battery will provide parallel connection to all of the hardware. It is important that the cable and wires are connected correctly to avoid damage to the hardware, since a large amount of current flows within this power harness which is about 30A to each motor.

The electronic speed controllers are attached to each aluminium pillars and the connected to the power harness. These are strategic locations for the ESC since there will be a motor on each end of the pillars while also being close to the APM flight controller board to allow signal wire connections. These ESC are secured with zip tights to avoid them moving around during flight.

A power module is also attached to the power harness to provide safe power supply to the APM flight controller board. Any excess power load onto the board will fry the APM flight controller therefore this power module is used as protection to avoid that situation to happen.

The power harness is covered with different layers of plates and then the APM flight controller is placed on the top. Plastic screws are used to avoid conductivity to the electronics on the board. It is critical that the APM controller board to be placed precisely at the middle of the frame so that the controller can balance the quad copter properly during flight. The front arrow indicator is directed towards the yellow aluminium pillars to set them at the front side.

The brushless motors are secured firmly at each ends of the frame. Its wire cables are attached directly to the ESC. The yellow wire is the signal wire, red and black are the live and ground wires. Yellow wire from the motor must match with the yellow wire on the ESC. However red and black wires can be switched in the opposite way around if required. This will only effect the rotation direction of the motor. The correct way of installing the brushless motors are when each motor rotates in the direction which cancels out each other.

For safety reasons each motors are fixed to the frame with plastic screws. This allows it to the motors to break loose from the frame in case of accidents. The result of this is that the frame can be protected from serious damage during crash scenarios.

The propeller 11 inch propeller blade is secured on top of the motor according to its direction of rotation. This is to ensure that air is pushed downwards which gives lift to the quad copter. Incorrect installation of propellers will result the quad copter to be stamped towards the ground and will not fly.

Importantly, the propellers must be locked properly before flight. Any loose installation of the propellers will cause instant crash to the quad copter since the quad copter requires all of the propellers to be functioning perfectly for stable flight. 

The rc module and gps module is placed at the vacant areas of the quadcopter. These modules are sealed at their places with zip tights. Strategically the gps module the rc module is attached outside of the frame so signal transmissions can be received efficiently.

The gps module and the rc module do not require independent power supply input as they feed power from the APM flight controller board.

The assembly of the quad copter is completed by attaching the signal wires from the speed controllers and the rc module at the correct positions on the APM flight controller board.

The final stage of the quad copter development is to connect the APM flight controller to its software. The software is named APM flight planner. Prior to use of the quad copter its firmware must be updated first. Then the hardware on the board such as the accelerometer, gyrometer and its magnetic compass needs to be calibrated. Finally the input from the rc module is calibrated and setup for flight modes and fail safe are configurated. 

Other than that, each ESC also needs to be calibrated. This is to allow the speed controller command correct speeds to the motors with its corresponding signal input. Failing to calibrate the ESC will cause the motors to spin unevenly.