Friday, 20 March 2015

Auto-pilot drones take to the air… and sea

The Broadcast Bridge

​Innovation in UAV filming space is extended to automated tracking systems which operate without camera-op or pilot. Broadcast Bridge looks at three systems all kickstarter funded and all in development including one designed for aquatic photography.
Hexo+ is a kickstart-funded project that has already raised $1 million. Its software is capable of autonomously flying a drone, filming and following an object controlled by a 3D model of the camera’s point of view on a smartphone app.
In theory, when users can set the framing on a smartphone and lock into a filming target (a BMX rider, for example). The drone will automatically take off and fly to its specified position – and hover there until the subject starts moving. The drone is “attuned to the slightest of movements, continuously repositioning itself to match the filming parameters you set for it.”
The drone itself is a Hexacopter (six blade) design weighing 2.2lbs and dimensions of 62 x 52 x 12 cm - 24 x 20 x 5 inches. Flight time is rated 15 min with 3S battery, gimbal and GoPro attached with operation over up to 2km distances.
“You might think this is borderline magic, but it’s actually all orchestrated by a smart and lean use of technology,” explain Hexo+ on its website. “On the smartphone side we have an intuitive interface for users to position the drone where you want in space and potentially Wi-Fi video live feed. This user interface is backed by trajectory anticipation algorithms that crunch data coming from the sensors on the drone and smartphone to predict the next, most likely position of the subject. This enables a quick, accurate tracking of the subject and is key in achieving great images. The smartphone and the drone communicate relative position to each other and data over the MAVLINK protocol, developed by the ETH in Zürich.”
The onboard software is based on the 3D Robotics open-source code, and Hexo+ optimised the MAVLINK implementation and the behaviour of the drone to improve response time to commands sent from the mobile app. It also integrated over the air gimbal control to obtain the best possible camera angle based on the relative positions of the drone and the subject.
Development has progressed to working prototype. “We’ve been ramming through hardware and software hurdles until last month, when we managed to consistently make our prototype work in field conditions,” the team states. “The drone is fast and agile, and the flight controller as responsive as we want it to be – from our action sport movie-making people perspective.”
To leap to industrial production (to make HEXO+ affordable at $499 each) requires further kickstarter funds to pay for moulds, minimum orders on parts and build. It hopes to launch commercially in May.
The development team
is led by CTO Christophe Baillon and William Thielicke, the design team by CEO Antoine Level, Telecom & Electronic Engineer Xavier De Le Rue and professional snowboarder and action sports movie maker 
Matthieu Giraud.
There is a catch. There is no avoidance system included in the first version. Instead, users will have to film in open areas. “Picture yourself driving a car with a trailer - you have to anticipate the trajectory of the drone following you,” the developer advises. It is working on an avoidance system. “So far it looks promising but we can't yet commit to a release date.”
Helico Aerospace Industries, led by Latvian inventor Edgars Rozentals is readying AirDog for release after securing $500,000 in kickstarter investment. It originally set a date of November 2014 for the release of its $1,295 unit which is controlled by a wrist-worn wireless leash at a range up to 1000 feet (300m).
Among the upgrades still being tested are heated units that keep critical sensors like gyroscopes and accelerometers at a constant temperature. This is to counter a problem caused by changing temperatures (such as filming snowboarders in sub zero cold) which causes the sensors to drift and the drone to crash immediately after takeoff.
This is typically solved by manual recalibration of sensors for each flight in different temperatures or mathematical correction if the characteristics if the drift are known at different temperatures. Helico says it has turned to the military for a solution by stabilizing the temperature - literally heating sensors up to certain temperature that is significantly higher then the possible maximum ambient temperature and keeping it stable while the drone is turned on. This requires about 40 seconds warm up time and tests are ongoing.
The team is testing two types of sensor for a collision avoidance system. One are LIDARs from the Pulsed Light company, the other being sonars from MaxBotix in both a high performance ultrasonic rangefinder and a waterproof version. The latter is apparently twice as expensive but useful for humid conditions. Helico seems to be erring on the side of LIDARS since it recently switched to a more robust PWM interface (from a i2C interface) and claims this is the main reason it has been still holding back with beta test unit shipping.
However, it is also investigating microwave radar which could serve well for active obstacle avoidance. “We are still waiting for snow to test sensor capabilities to detect ground on reflective and sound dampening surfaces,” Helico states.
The drone itself is has a top speed of 40 mph and the battery is a 14.8 V LiPo.
The third auto-pilot kickstarter project looks at first sight more of a gimmick than the others but could have pro potential for sports like America's Cup. Splash Drone is a quadcopter encased in a buoyant waterproof shell, so it can safely land and float on water without being damaged.
It's got a waterproofed housed-gimbal for fitting a Go-Pro and features auto-follow functionality, so it can shoot video autonomously while you play, surf, jet ski, wakeboard, canoe, white water raft etc etc in the water. The top speed is 25 mph. It is currently on track to reach $100K in funds, way past its target of $17,500 and is expected to ship in July.
“We've tested several camera gimbal configurations and are working on testing the latest prototype in fresh and salt water,” explains project lead Alex Rodriguez on kickstarter. “The major challenges were waterproofing the giro stabilization board and the signal cables. We used the same concept as the GoPro dive box and are now testing it for endurance.”

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