Design of Flight Control Systems for a Hypersonic Aircraft Using sliding-PID Control

The paper presents the application of sliding-PID control to the design of robust flight control system for a hypersonic aircraft. The proposed controller uses an approach that combines the high-order PID controller with high-order sliding mode (HOSM) control. The PID uses high-order time-derivative (HOTD) function of the sliding mode variable while the HOSM uses the signum function of the HOTD function. HOTD is built using the relative degree nonlinear dynamics of multivariable systems driven by affine control inputs. A displacement autopilot is designed for pitch control of an air-breathing hypersonic vehicle model. Numerical simulation demonstrates the effectiveness of the proposed controller and shows its advantages as compared to the quasi-homogenous HOSM controller

Single-Rotor Helicopter Dynamics and Maneuvering Simulation

This paper presents the development and validation of a robust flight dynamics model for simulation of a full-scale single-rotor helicopter dynamics and maneuvering. A minimum-complexity dynamic model is used to compute the aerodynamic forces and moments using trajectory-planning strategy. A high-order sliding mode (HOSM) observer is used as a numerical differentiator for computing time rate changes of longitudinal and lateral control inputs to the main rotor dynamics during maneuvering. The HOSM differentiator suppresses numerical instability and increases computation accuracy of both dynamic and kinematic characteristics. Using available data and flight test results for UH-60 helicopter, the control input characteristics are interpolated versus flight speeds. A pull-up maneuver is simulated to demonstrate the effectiveness of the proposed model

Numerical Assessment of the Thermomechanical Properties of the NiTi Shape Memory Alloy

The paper presents a numerical assessment and characterization of Shape Memory Alloys (SMAs) thermomechanical behavior using an internal variable approach-based constitutive law. A simulation study is conducted to reveal the influence of the key intrinsic properties such as shape memory effect, pseudoelastic effect, hysteresis loop, and non-constant material functions on the loading capacity and thermal actuation of SMAs. The effects of initial conditions, residual strains, and high temperatures on the behavior of SMAs are studied through several thermomechanical loading-unloading scenarios. The results give useful indications on the capability of SMA materials to fully recover large strains under thermal activation, to change their properties reversibly through phase transformation, and to serve as actuator systems for engineering control applications

Consensus Tracking for Multiagent Systems Under Bounded Unknown External Disturbances Using Sliding-PID Control

This paper is devoted to the study of consensus tracking for multiagent systems under unknown but bounded external disturbances. A consensus tracking protocol which is a combination between the conventional PID controller and sliding mode controller named sliding-PID protocol is proposed. The protocol is applied to the consensus tracking of multiagent system under bounded external disturbances where results showed high effectiveness and robustness

A Novel Higher-Order Sliding Mode Control Scheme for Uncertain Nonlinear Systems: Short-period Missile Control Application

The paper proposes a novel higher-order sliding modes (HOSM) control scheme for a class of uncertain nonlinear systems. The HOSM-based control scheme is developed based on the Filippo

Numerical and Experimental Investigation of Carbon Fiber Composites Subjected to a Discrete Source of Damage

The paper investigates the effect of a discrete source of damage on the loading capacity and failure strength of composite materials. First, the effects of varying fiber orientation on the distribution of the circumferential stress around the source of damage and on the failure strengths of continuous fiber-reinforced composites were investigated using theoretical approaches developed for infinite-plate with a central hole. Numerical simulations were conducted and spatial graphical illustrations were plotted using fiber orientation angle and angular location on the circumference of the hole as analysis variables. Tsi-Wu failure criterion was employed to predict the failure strength of a composite layer subjected to a discrete damage with a varying fiber orientation. Second, experimental tests using specimens with and without damage were carried out to find out the impact of discrete damage on the loading capacity and failure strength of woven Carbon-epoxy composite laminates. A qualitative analysis was performed to evaluate the effect of the size of damage on the structural performances of laminated composites

Cooperation Attitude Control as a Part of Spacecraft Formation Flying

Cooperative and coordination control for Autonomous Multi-Agent Systems (AMAS) are gaining more popularity and interest in many areas of aerospace engineering, such as air-traffic control, swarming satellites, launch/reentry-vehicle systems, and Formation Flying (FF). There are many advantages of cooperative control of autonomous FF of multiple small aerospace vehicles to replace a single large vehicle, such as increasing feasibility, reducing cost, probability of success, and significantly widening the operating area. For example, a group of cooperative Earth Observation radar satellites can enhance the overall resolution by observing backscattered signals from different angles compared to one giant costly satellite observing from one angle. Aerospace FF applications include distributed antennas, atmospheric sampling, and synthetic aperture radars. Besides, it is appealing to have robust and optimal control for space manufacturing and servicing. The Nano/microsatellites market is expected to grow as more companies develop smaller, cheaper launch vehicles. This paper demonstrates a model-based design for decentralized cooperation control as part of spacecraft formation flying using a single-integrator dynamic for deep space exploration missions

Chatter-Free Distributed Control for Multi-agent Nonholonomic Wheeled Mobile Robot

This paper proposes to design a chatter-free distributed control for multiagent nonholonomic wheeled mobile robot systems employing terminal exponential functions with graph theory. The terminal tracking criteria are estimated using the Lyapunov approach. The development of distributed control for nonholonomic multiagent wheeled robot systems is defined in the paper along with consensus tracking for undirected fixed/switched topologies. Numerical simulations have been done in order to assess the efficacy and efficiency of the proposed distributed control method in multiple scenarios

Simulation of Transonic Compressor Performance Deterioration Due to Sand Erosion

Air sand erosion is a widely effecting phenomenon in GCC region, where a solid particle impacting on a wall surface causing catastrophic mechanical damage, the engine compressor operating in a particulate environment are subjected to deterioration of performance and life due to sand ingestion. In current paper we simulate and studied the sand erosion in such transonic compressors were flow rate, particle size and concentration were investigated to study particles distribution and erosion rate along the compressor blade. Result shows that particles concentration has the most significant effect on blade erosion rate where particles size has less effect among all other measured parameters. Surface deformation and roughness is in scope for further investigation