Designing Human-Centered Automation and Cockpit Displays to Enhance Pilot Situation Awareness
EduQuad Balancing Games
Raymarine Evolution Autopilot using L1 Adaptive Control
Raymarine has marketed their Evolution Autopilot for marine vessels. The autopilot encompasses an L1 adaptive controller and eliminates the need for a complicated setup and calibration. More information on the Evolution Autopilot can be found at the product page.
Autoquad M4 – Kisssystems
Another successful flight of an AutoQuad augmented with L1 Adaptive control developed by Kisssystems.
IFAC Award paper
“The Article: ‘L1 adaptive manoeuvring of unmanned high-speed water craft’ got the prestigious ‘Best Paper Award’ at the IFAC Conference MCMC 2012 (Marine craft manoeuvring control) in Arenzano, Italy.”
Click here to read more details and download the full paper.
Position Trajectory Tracking of a Quadrotor Helicopter based on L1 Adaptive Control
Abstract: “We present an adaptive backstepping controller for the position trajectory tracking of a quadrotor. The tracking controller is based on the L1 adaptive control approach and uses a typical nonlinear quadrotor model. We slightly modify the L1 adaptive control design for linear systems to comply with the time-varying nonlinear error dynamics that arise from the backstepping design. Our approach yields a stable adaptive system with verifiable bounds on the tracking error and input signals. The adaptive controller compensates for all model uncertainties and for all bounded disturbances within a particular frequency range, which we specify a priori. The design of this frequency range involves a trade-off between control performance and robustness, which can be managed transparently through the L1 adaptive control design. Simulation results show the powerful properties of the presented control application.” [pdf]
Autoquad position holding
The following video shows an autonomous position holding control of an AutoQuad using only onboard sensors (ultrasonic range finder and downward facing optical flow sensor). This solution is ideal in cases where GPS is not available.
Helicopter Flight Simulator
L1 controller for a generic light utility helicopter. The simulation is manually piloted and includes sensor noise and actuator saturation. A vertical speed controller is active that commands hover if the collective lever is pulled back to a region near the original hover position.
A Comprehensive Flight Control Design and Experiment of a Tail-sitter UAV
In this paper, the authors present an autonomous Take-Off and Landing of a Tail-sitter UAV
“There have been ongoing interests in a type of aircraft that are capable of vertical take-off/landing (VTOL) for greater operability and high-speed horizontal flight capability for maximal mission range. A possible solution for such application is tail-sitters, which takes off vertically and transitions into a horizontal flight. During the entire mission of a tail-sitter from take-off to landing, it goes through largely varying dynamic characteristics. In this paper, we propose a set of controllers for horizontal, vertical, and transition flight regimes. Especially, for transition, in conjunction with conventional multi-loop feedback, we use L1 adaptive control to supplement the linear controllers. The proposed controller were first validated with simulation models and then validated in actual flight tests to successfully demonstrate its capability to control the vehicle over the entire operating range.”
Click here to view the full paper.
Below you can find the flight test results.
A Guidance and Control Law Design for Precision Automatic Take-off and Landing of Fixed-Wing UAVs
In this paper the authors present an automatic take-off and landing control system for fixed-wing UAVs augmented with L1 adaptive control.
“This paper presents an automatic take-off and landing control system (ATOLS) for fixed-wing UAVs. We propose a guidance and control system to satisfy the requirement for high-precision landing using arresting wires. For trajectory tracking, Line-of-Sight (LOS)-based longitudinal and lateral guidance laws are derived. For the design of inner loop controllers, linear models are identified directly from the flight data. In order to maintain the consistency of the control performance in the presence of flight regime changes during take-off and landing, the linear baseline controller is augmented with a compensator designed using L1 adaptive control theory, which eliminates the need for conventional gain scheduling. The proposed control system is implemented on a scale Cessna UAV with an arresting hook for validation. The proposed take-off and landing system demonstrated a consistent performance in a series of test flight on a full-scale carrier model.” [pdf]
EduQuad360 RTF based on AutoQuad with L1 adaptive control
“EduQuad, from Viacopter and Unmanned Dynamics, is a remote-controlled multirotor helicopter with 4 rotors, based on the AutoQuad platform and L1 adaptive control from Unmanned Dynamics. The system can be flown manually, in position hold or fully autonomously.”
L1 adaptive depth control of an underwater vehicle in the presence of uncertainties and disturbances
“This video shows experimental results of depth control obtained at LIRMM (Laboratoire d’Informatique de Robotique et de Microélectronique de Montpellier), University Montpellier 2 – CNRS, France. The horizontal displacements are left uncontrolled. The L1 adaptive controller is applied to control the depth. This controller is robust towards uncertainties (e.g. floatbility, damping…) and well rejects external disturbancies (impacts, tether drag…). The prototype is a modified AC-ROV.”
L1 based controller on Albatross hexarotor
The video shows the flight tests of an Albatross hexarotor.
AutoQuad L1 testing
What would happen if one motor shuts down? Check out this video made in The Netherlands, where L1 controller is implemented on an hexarotor UAV’s autopilot. Even when one propeller is missing, stability performance are guaranteed.
Non-cascaded Dynamic Inversion Design for Quadrotor Position Control with L1 Augmentation
Flight test results from TU Munich. The work is the result of this paper.
“This paper presents a position control design for quadrotors, aiming to exploit the physical capability and maximize the full control bandwidth of the quadrotor. A novel non-cascaded dynamic inversion design is used for the baseline con-trol, augmented by an L1 adaptive control in the rotational dy-namics. A new implementation technique is developed in the linear reference model and error controller; so that without causing any inconsistency, nonlinear states can be limited to their physical constraints. The L1 adaptive control is derived to compensate plant uncertainties like inversion error, disturbances, and pa-rameter changes. Simulation and experiment tests have been per-formed to verify the effectiveness of the designs and the validi-ty of the approach.”
Quadrotor’s Flight Test
Our collaborators at Unmanned-Dynamics implemented L1 backstepping adaptive control on a Quadrotor UAV.