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Mini Helicopter
Our group's main focus is on rotary winged vehicles aka Helicopters, their cousins and their other family members such as Wind Turbines. We are part of the Helicopter Lab where we are trying to solve some of the fundamental problems associated with the development of autonomous Micro (Micro Coaxial Autonomous Heli), Mini Helicopters and Wind Turbines. Apart from the MAV related work, we are also actively involved in barrier problems associated with Helicopter dynamics, aerodynamics and flight dynamics. Focus is on the development of state-of-the-art tools to be used in industry for the design of future generation helicopters with the aim of attaining self reliance in helicopter analysis and prediction capability.
Project NAAVIK (Navigation for Autonomous Aerial Vehicles by IIT Kanpur)
NAAVIK aims to be an open source cross platform / vehicle autopilot project meant for UAV / MAV applications being developed at IIT Kanpur MAV laboratory. It is developed on ChibiOS RTOS (Real Time Operating Syetem) for NAVSTIK autopilot hardware which is among the lightest open source autopilot hardware out there and is developed by NavStik Inc., a Pune based company.
NAAVIK has already been tested on a fixed wing UAV for fully autonomous flight. It has also been tested on coaxial MAV, flapping wing MAV and Quadrotor. Objective is to develop NAAVIK for application on wide range of UAV platforms. Below is a video of its application on Quadrotor.
Micro Coaxial Autonomous Heli (MiCAH)
Goal is to develop a hover capable, autonomous Micro Air Vehicle. The desired characteristics include capabilities such as auto-take off and landing, autonomous hover with velocity and position hold followed by autonomous flight with way-point navigation. The platform chosen for this work is a Coaxial Micro Air Vehicle instrumented at IIT Kanpur (see image below) using optic flow sensors, IMU, infrared sensors and SONAR. The above milestones would be achieved in a step by step manner. Significant progress has been made in the autonomous take off capability as well as autonomous hover using velocity feedback.
Autonomous Hover
A video showing MiCAH performing autonomous hover with "velocity" feedback obtained from a combination of Optic flow + IR sensor is included below. Currently work is underway to characterize the vehicle dynamics for improved hover performance.
Auto Take-off and Landing for a VTOL MAV
One of the preliminary requirements for a fully autonomous VTOL MAV is the ability to take off and land automatically. The goal of this research is to develop such a system for coaxial MAV degined for indoor operations.
Auto Take Off and Landing (ATOL) are difficult maneuvers to perform due to its transient nature and control precision required. A suitable optic flow sensor with high speed motion detection (6400 fps update rate, 30 x 30 pixel resolution) is chosen as the sensor. Various lenses with different focal lengths are considered for measuring optic flow over a distance of about a foot. The auto take off and landing of a rotary wing MAV with VTOL capability might require installation of multiple optic flow sensors, use of a single optic flow sensor is also considered.
Design and Development of Coaxial MAV
MAVs are aerial robots, as six-degree-of-freedom machines whose mobility can deploy a useful micro payload to a remote, constrained or otherwise hazardous location. Goal is to design and build as well as analyse a coaxial (counter rotating twin rotor) hover capable Micro Air Vehicle (MAV). Image below shows the conceptual design of the vehicle.
And this is how the real thing looks like. Several prototypes have been designed and built at IIT Kanpur. Image below shows the recent prototype in flight.
Flight video:
Realtime Obstact Avoidance Using Microsoft Kinect Sensor
Flying in constrained indoor environment under out-of-sight scenarios pose new challenges for control and navigation of MAVs. Position feedback is necessary for vehicle stability as well as fully autonomous out-of-sight flight capability. This remains a big challenge, as the conventional solution for outdoor flight vehicles, GPS, cannot be used indoors. This may warrant investigation into non-conventional methods of position feedback, such as optic flow sensors, lasers, vision based navigation etc. Before a robust and reliable methodology for position feedback could be developed, a collision avoidance system is the first step in the direction of autonomous flight capability.
The obstacle avoidance system was originally implemented on a terrestrial bot called StreakAuto. The algorithm has now been ported to a BeagleBoard single board computer for its deployment on an MAV. Our coaxial Micro Air Vehicle MiCAH has an approximate payload capability of 150 gm, therefore it is not adequate to lift a stripped down Kinect which along with Beagleboard weighs 220 gm. Therefore a new flight vehicle was conceptualised and built (see figure below). It is a 4 rotor vehicle with two sets of coaxial rotors joint together using carbon composites. The bottom rotor of each set is controlled in a symmetrical manner using swashplate.
The vehicle shown above showed strong pitch / yaw coupling which required special attention. Therefore, a regular coaxial was modified to improve its payload capability by replacing stock motors with brushless motors and using longer blades. It was further modified to house stripped down Kinect, a quad core single board computer to achieve realtime obstacle avoidance. The realtime obstacle avoidance video is shown on the home page.
Inverse Flight Simulation for Helicopter Undergoing Unsteady Manoeuvre
For the steady flight a helicopter is trimmed to maintain the equilibrium condition, this is achieved by evaluating the control angles, tail rotor collective and shaft angles orientation to match a desired helicopter steady state. But for unsteady manoeuvres a time history of control angles, tail rotor collective and shaft angle orientations is needed to achieve a particular trajectory. This process of calculation of pilot inputs required to achieve a particular trajectory or manoeuvre is referred to as inverse simulation. The goal of this work is to develop inverse simulation capability without significant computational penalty.
Design and development of an Autonomous Tiltrotor Aircraft
Tiltrotors try to bridge the gap between helicopters and aircrafts. A prototype has already been fabricated which has been tested in hover and gliding flights. Transition flights would be tested soon. Next step would involve the challenging task of development of flight control system for autonomous transition from hover to forward flight.
Design of Vertical Axis Wind Turbine with Variable Pitch
Vertical Axis Wind Turbines (VAWTs) appear to be an attractive option due to their compactness. However, the fixed pitch VAWTs are not very efficient. Goal is to address these issues by desiging a variable pitch wind turbine and bring in innovations to provide consistent performance over wide range of wind speeds, irrespective of the wind direction. A lab scale prototype has already been fabricated and wind tunnel tests are being planned. In addition, double multiple streamtube based analysis has been developed to characterize the performance and size the turbine for household applications.
Coaxial helicopter with a flybar is passively stable, which makes it easy to fly but at the same time compromises its maneuvering capability. So we got rid of the flybar which makes the vehicle very unstable. Active stabilization is achieved using onboard sensors. Vehicle with active stability if far more agile. See it in action below:
Autonomous Flight of Mini Helicopter (Align T-rex 700)
