Our mapping drone was developed by our chief pilot Peter Jones. He wanted a drone that was safe, reliable, and capable of carrying high quality sensors.
There are several off the shelf drones that all had their good and bad points, but there wasn’t a drone that was able to fulfill all the criteria set by Peter.
The only sensible option was to custom build a drone to meet our exact specification, to fulfill all our requirements.
Many hours of research and development have gone in to our drone to ensure it can deliver time and again.
The development process took several months of study and testing to make sure our drone was up to the task.
The frame of a multirotor is like the skeleton that holds all the other components together.
It is important that it is strong enough to endure the stresses and strains imposed by active flight but at the same time it needs to be lightweight to maximize flight times and maneuverability.
We chose a Tarot T810 frame as the base for our drone.
This is an all carbon fiber frame which means it is lightweight as well as being exceptionally strong.
Carbon composites are used in all sorts of high end applications from formula one cars to medical equipment.
The T810 is also foldable which make our drone easier to transport to and from site.
All multirotors require a flight controller to make them fly. The arrangement of the motors on a drone means they are inherently unstable. The flight controller uses advanced microprocessors and a variety of sensors such as gyros, accelerometers, barometers as well as GPS to keep the aircraft stable. Every second the drone is in the air the flight controller is making millions of calculations and adjustments to make the drone obey the commands of the pilot in charge. There are many different flight controllers available on the market today, ranging from quite basic to controllers that have advanced flight functions and automation built in.
We chose to install a Pixhawk flight controller on our drone.
The Pixhawk is an industrial flight controller developed by 3DR Robotics in America. It has advanced autonomous flight capabilities as well as multiple redundant sensors that enable a degree of additional safety compared to other flight controllers. The reason we like the pixhawk is because of the open hardware that has allowed us to integrate more advanced telemetry and safety options that are not available on other proprietary brands.
In order to get off the ground the drone needs to be able to produced enough lift to support itself as well as any payload. To do this drones have powerful motors and high capacity battery packs that allow the propellers to generate the needed thrust.
This thrust is also used to manoeuvre the aircraft, by increasing or decreasing the power to each motor.
We chose to use the DJI E600 tuned propulsion system because the motors and electronic speed controllers are matched to ensure optimum efficiency. The E600 motors are each capable of producing 1600g of thrust, thats a total of 9.6 kg of thrust from our drone.
We chose a hexa-copter configuration with six motors because this setup gives us the added security of still being able to fly with the loss of one motor or propeller.
Batteries are also a crucial part of the power train. Modern Lithium Polymer batteries have enabled drones to fly longer and carry more weight. We use two 6600mah lipo batteries in parallel that enables us to fly for 20 minutes.
We have advanced voltage and current sensors produced by Mauch Electronics that individually monitor the voltage and capacity of each of the batteries. Our sensor hub constantly measures the health of our battery system and if it detects any anomalies it warns the pilot so he can make an emergency landing.
Telemetry is key to ensuring safe flight. The pilot in control needs to know what’s happening with his drone at all times.
We use the Frsky Taranis Plus for our radio control system primarily because it has advanced telemetry functions. By using the Taranis we have been able to integrate a Teensy 3.2 microcomputer to transmit all the flight data logged by our Pixhawk to the hand held radio so the pilot doesn’t have to look at a ground station for information.
The Taranis is also able to use voice prompts so the pilot doesn’t need to take his eyes of the drone to monitor the telemetry. Our radio system also issues audio warnings should there be a problem with the drone.
All this telemetry data is logged to an internal SD card in the Pixhawk as well as another SD card in the Taranis. This data is used as part of our reporting procedure to the CAA and is incorporated in the pilot’s log book of flying hours.
So what happens when a drone has a catastrophic failure during flight?
This question has kept us awake at night thinking of what could happen should our drone fall out of the sky.
The best solution is not to let this situation develop in the first place, which is why we have worked so hard with our telemetry system to ensure we get an early warning of a system failure, but as the Mythbusters say "failure is always an option!"
We did a lot of research in to failure containment systems and we came to the conclusion that a parachute system would offer the best solution to a major malfunction of our drone.
We considered several different systems and eventually decided on installing a Skycat X55 parachute system. The pilot can deploy the parachute manually by flicking two separate switches on the Taranis radio or the Pixhawk flight controller has an automatic eject function should it detect an anomaly during the flight.
The parachute system is completely independent of the main batteries and can be deployed even if a complete failure of both batteries takes place.
We hope you have found this page informative and it has helped you to see our commitment to professionalism and safety in the drone industry.
If you would like to learn more about the technology used in our mapping drone please visit the links below for more details.
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168 MHz / 252 MIPS Cortex-M4F
14 PWM / Servo outputs (8 with failsafe and manual override, 6 auxiliary, high-power compatible)
Abundant connectivity options for additional peripherals (UART, I2C, CAN)
Integrated backup system for in-flight recovery and manual override with dedicated processor and stand-alone power supply (fixed-wing use)
Backup system integrates mixing, providing consistent autopilot and manual override mixing modes (fixed wing use)
Redundant power supply inputs and automatic failover
External safety switch
Multicolor LED main visual indicator
High-power, multi-tone piezo audio indicator
microSD card for high-rate logging over extended periods of time