The surveillance helicopter will be animplementation of an unmanned aerial vehicle(UAV) using a radio-controlled (RC) helicopter that iscapable of following a moving, at a fixed altitude offthe ground while maintaining wirelesscommunication with a remote controller.These are the days of modern technologies and inorder to achieve supremacy in various sectors,modern technology should be adopted.This is an effort to make a prototype of Surveillancechopper, which can be used as a spying machine orfor surveillance.
History• First fully controllable R/C model helicopter appeared, built by Dr. Dieter Schluter of West Germany in the year 1968.• But first really successful British R/C Auto Gyro, a semi-scale model of the Wallace Autogiro, was first flown in 1978, ten years after the first appearance of the R/C helicopter.
Radio-controlled helicopters Radio controlled helicopter are the choppers which are controlled by radio signals. Small fixed-pitch helicopters need a 4-channel radio (throttle, elevator, aileron, rudder)Because of the normal interaction of the various control mechanisms, advanced radios include adjustable mixing functions, such as throttle/collective and throttle/rudder.
Design Construction is typically of plastic, glass-reinforced plastic, aluminium or carbon fiber. Rotor blades are typically made of wood, fiberglass or carbon fiber. These model helicopters contain many moving parts analogous to those on full-size helicopters, from the swash plate to rotor and everything in between. The construction of helicopters has to be more precise than for fixed-wing model aircraft, because helicopters are susceptible to even the smallest of vibrations, which can cause problems when the
Design Cont… Auto Rotation Capability – Yes Bell Mixing – Yes CCPM (Cyclic-Collective-Pitch-Mixing)– Yes 120 degree Main Frame Material – Plastic / Tail boom – Aluminum Rotor Diameter – 718mm Tail Rotor Diameter – 135mm Tail Rotor Drive – Belt Driven Weight with battery – 665g
Various parts of Helicopter Main RotorThe main rotor blades generate lift by spinning in a clockwise motion and pushing air downward. Theymove anywhere from +/-10 degrees pitch. Tail RotorThe tail rotor counteracts the torque of the blades. It pushes air against that torque in a counterclockwise motion to stabilize the aircraft. Landing GearThe landing gear is better known as the skids, and will not be used directly until you can competentlyhover the aircraft
Gyro The gyro keeps the tail of the helicopter mostly stationary. When a gust of wind hits the helicopter from the side, the gyro stabilizes the movement. It is connected between the rudder servo and the rudder spot on the receiver. Gyro Model used in our project – E-Flite G110 Heading Hold – Yaw Rate and Gain Remotely Adjustable.
Brushless running servo Motor It can handle a lot of current, and it will fly the helicopter for over several minutes. The motor has a pinion gear that drives the main gear and a tail rotor via a belt. It is approximately 1/3 more efficient than the standard brushed stock motor that comes with the helicopter. Motor used in our project – E-Flite 420Heli brushless 3800Kv
- ESC - ElectronicSpeed Control The throttle control is handled by the ESC. It provides a smooth power distribution to the motor and accepts the LiPo style batteries in cut-off voltages and high current applications. The ESC used in our project has a rating of 25 amps max current. BEC - Battery eliminating circuit and it would power the servos from the flight pack. This ESC lacks that option, so it is necessary to use a separate 4.8V NiCad to power the servos.
Battery Motor Battery The proposed motor battery to be used in our project will consists of 3 batteries of 1800 mAh, (11.1V) Li-Po battery. It is rated at 20C continuous discharge. The battery is held in place using rubber bands for easy removal and vibration resistance.Receiver & Receiver Battery The receiver which interprets signals from the transmitter needs to be carefully attached the frame of the helicopter In the picture shown, it is wrapped in foam rubber which was supplied with the receiver to prevent vibrations from destroying it
ModulationRadios emit the FM signal in two types of modulation.PCM (Pulse Code Modulation )Pulse Code Modulation is a scheme in which the commanded position for each servo is transmitted as a digitally encoded number.PPM (Pulse position modulation )Pulse position modulation is a scheme in which the commanded position for each servo is transmitted as the duty-cycle of the transmitted pulses 1 per servo position.
-Transmitter Setup The signals are mixed in the Transmitter and sent to the receiver. While operating radio its necessary to work with the antenna fully extended. The transmitter has a circuit that is designed to send a signal. When it is collapsed, the circuit overloads and will eventually burn out. Receiver Model – Spektrum AR6100e 2.4 GHz DSM2
- Transmitter The Futaba T9CHP transmitter we will be using has a large LCD screen on it for programming the helicopter. The voltage may be different, but thats about it. By setting up, S1, S2 and MDL, these are all timers that can enable setup to let ourselves know how long weve been flying.
- Pitch Curve Setting up the pitch curve is not difficult but requires some planning. As the collective/throttle stick moves upwards, we need a slow and smooth movement of the blades. The blades need to move to a high enough degree/pitch setting or the helicopter will not take off. Too much pitch and the blades will stall, and the helicopter will fall out of the sky.
- Throttle Curve The throttle curve is mixed with the pitch curve. Looking at both graphs at once enables us to see how they interact with each other. The throttle setting moves upwards quickly, and stays at a near constant level to achieve flight.
- Charging the battery To charge the LiPo motor battery (2Ah), we will need a high current 12VDC source, a closeable fireproof container, an open area such as a concrete floor, and the charger. The box is not airtight because the charger needs fresh air to remain cool. The fan on the charger is noisy, so placing it in a closed box muffles it pretty well. The toolbox setup provides a nearly 100% safe way to charge the LiPo without any fear of fires.
- Wireless camera Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band.
Applications RC helicopter may be used in the following fields:- Defense surveillance Spying Grid inspection Fire extinguisher Mobile Tower inspection Metrological inspection
Conclusion This is an effort to make a prototype of Surveillance chopper, which can be used as a spying machine or for general surveillance. These days are the days of modern technologies and in order to achieve supremacy in defence sector, every modern technology should be adopted by Indian armed force, this is a prototype of Unmanned Aerial Vehicle (UAV).
Future Scope Coil Gun GPS can be installed and hence all the specific location can be retrieved.
References Wikipedia An introductory guide for operating Radio Controlled Helicopters by MICHAEL VOICHECK RC group tutorial Control Systems Engineering, Norman S. Nice http://www.rchelicopter.com/2007/11/22/dragan flyer-uav-vanderbilt-university-drone/ http://en.wikipedia.org/wiki/Gumstix