Fractional Differential Equations

Adaptive attitude tracking control for rigid spacecraft with finite-time convergence

http://www.nt.ntnu.no/users/skoge/prost/proceedings/ifac2014/media/files/1833.pdf

Adaptive continuous higher order sliding mode control

The science objectives of a spacecraft mission place stringent performance requirements on the spacecraft attitude control system. However, it remains an open problem how to guarantee consistent control performance necessary to meet these requirements, especially in the event of actuator faults and input saturation. Motivated by this fact, in this paper, we address the problem of attitude tracking control with prescribed performance guarantees for a rigid spacecraft subject to unknown but constant inertia parameters, unexpected disturbances, actuator faults, and input saturation. First, certain performance functions specified a priori by the designer are adopted to impose desired performance metrics on the attitude tracking errors. Then, the original attitude tracking error dynamics with performance constraints is transformed into an equivalent “state-constrained” one whose robust stabilization is shown to be sufficient to solve the stated problem via a novel error transformation. Subsequently, based on the transformed system, an adaptive fault-tolerant controller is derived by incorporating backstepping control, the barrier Lyapunov function, and Nussbaum gains. It is proved that the designed controller is able to guarantee the satisfaction of the prespecified constraints on the transformed errors, as well as the boundedness of all other closed-loop signals, without resorting to a judicious selection of the control parameters. Finally, the effectiveness of the proposed control scheme is evaluated by means of simulation experiments carried out on a microsatellite.

Adaptive Fault-Tolerant Attitude Tracking Control of Spacecraft With Prescribed Performance

In this paper, a model-based robust control is proposed for the polymer electrolyte membrane fuel cell air-feed system, based on the second-order sliding mode algorithm. The control objective is to maximize the fuel cell net power and avoid the oxygen starvation by regulating the oxygen excess ratio to its desired value during fast load variations. The oxygen excess ratio is estimated via an extended state observer (ESO) from the measurements of the compressor flow rate, the load current, and the supply manifold pressure. A hardware-in-loop test bench, which consists of a commercial twin screw air compressor and a real-time fuel cell emulation system, is used to validate the performance of the proposed ESO-based controller. The experimental results show that the controller is robust and has a good transient performance in the presence of load variations and parametric uncertainties.

Disturbance-Observer-Based Control for Air Management of PEM Fuel Cell Systems via Sliding Mode Technique

A novel adaptive-gain supertwisting sliding mode controller: Methodology and application

Pneumatic actuator control: Solution based on adaptive twisting and experimentation

A new high-order sliding mode controller is proposed. The main features are gain adaptivity and the use of integral sliding mode concept. The gain adaptation allows a reduction of the chattering and gives a solution to control uncertain nonlinear systems whose the uncertainties/perturbations have unknown bounds. The concept of real high-order sliding mode detector is introduced given that it plays a key role in the adaptation law of the gain. This new control approach is applied by simulation to an academic example to evaluate its efficiency.

An adaptive solution for robust control based on integral high-order sliding mode concept†

Adaptive sliding mode strategies of first and second sliding orders are developed for single-input single- output systems of the first and second relative degrees respectively. Since the only concrete known uncertainty bounds are assumed to be the upper bounds of logarithmic derivatives, no standard sliding- mode technique can solve the problem

Mohammed Taleb

Papers

A novel adaptive-gain supertwisting sliding mode controller: Methodology and application

Pneumatic actuator control: Solution based on adaptive twisting and experimentation

An adaptive solution for robust control based on integral high-order sliding mode concept†

Adaptation of sliding modes

Lyapunov design of adaptive super-twisting controller applied to a pneumatic actuator