This paper presents an L1 adaptive output feedback controller for a class of uncertain nonlinear systems in the presence of time and output dependent unknown nonlinearities. As compared to earlier introduced L1 adaptive output feedback control architectures, the architecture in this paper relies on system inversion, and is therefore limited to minimum phase systems. Similar to prior solutions i...

This paper presents the application of an L1 adaptive control architecture to the problem of active dispersion management for propagation of Gaussian-shaped solitons along uncertain optical fibers. The derivations in the paper are based on a reduced variational model for optical soliton propagation. Simulation results demonstrate the benefits of the proposed closed-loop adaptive approach over e...

Positive systems represent a class of systems whose state variables are nonnegative. This paper presents an L1 adaptive controller for such systems. The control objective is to force the system output track a given nonnegative reference signal. In the analysis of the L1 adaptive controller, we first show the positivity of the constructed reference system, and then demonstrate that the controlle...

In this paper, the L1 adaptive control theory is used to design a high bandwidth inner loop controller to provide attitude and velocity stabilization of an autonomous small-scale rotorcraft in the presence of wind disturbances. The nonlinear model of the vehicle is expressed as a linear time-varying system for a predefined region of operation, for which an L1 adaptive controller is designed. Th...

This paper explores application of the L1 adaptive control architecture to a generic flexible Crew Launch Vehicle (CLV). Adaptive control has the potential to improve performance and enhance safety of space vehicles that often operate in very unforgiving and occasionally highly uncertain environments. NASA’s development of the next generation space launch vehicles presents an opportunity for ad...

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 noncascaded dynamic inversion design is used for the baseline control, augmented by an L1 adaptive control in the rotational dynamics. A new implementation technique is developed in the linear reference model and error controll...

This paper presents application of L1 adaptive controller to two benchmark flight control applications. The benefit of the proposed adaptive control approach is its promise for development of theoretically justified tools for Verification and Validation (V&V) of adaptive systems. It has apriori predictable performance bounds and guaranteed, bounded away from zero, time-delay margin in the prese...

this paper presents a new observer-based control scheme for a class of nonlinear systems. in the proposed method, nonlinear observer and twisting algorithm controller are employed to realize a sensor-less control strategy for complex systems which makes use of non measurable process information instead of installing as many sensors as possible. due to lack of availability of the complex system ...

Accepted version. Accepted at 2017 IEEE International Conference on Robotics and Automation. c ©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to serv...

Accepted version. Accepted at 2017 IEEE International Conference on Robotics and Automation. c ©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to serv...