Sahjendra n Singh

• University of Nevada, Las Vegas

The paper develops a composite adaptive flight control system for the trajectory control and parameter estimation. The composite identifier is designed using the information on the tracking error and two model prediction errors. The first model prediction error is a function of a regressor matrix derived from aircraft dynamics. The second predictio...

This article presents an adaptive orbit control system for spacecraft around irregularly-shaped rotating asteroids. It is assumed that the asteroid’s mass and inertia matrix are not known. Unlike the published articles, an adaptive orbit control system is designed based on a logarithmic manifold. In the closed-loop system, first the spacecraft traj...

In this article, we develop a novel composite adaptive control system for the dive-plane maneuvers and parameter identification of a multi-input multi-output submarine model. The composite adaptive control system consists of (1) an input–output feedback linearizing control law and (2) an identifier formed by gradient algorithm-based two-parameter e...

This article presents a state predictor-based composite adaptive flutter control system for a nonlinear multi-input multi-output (MIMO) aeroelastic system. The plunge and pitch motion of this 2-D airfoil is controlled by trailing- and leading-edge control flaps. All of the model parameters are assumed to be unknown. The uncontrolled airfoil shows l...

This article (correspondence) develops a composite adaptive control system for the attitude trajectory tracking of a spacecraft in elliptic orbit around a uniformly rotating asteroid. It is assumed that the spacecraft’s moment of inertia and the asteroid’s gravitational parameters are unknown. The adaptation law designed here includes a positive se...

View Video Presentation: https://doi.org/10.2514/6.2022-0493.vid This paper presents a $G$-passivity-based output feedback adaptive control system for the control of a projectile fin using a piezoelectric actuator. The rotational motion of the fin on the projectile is controlled by a flexible cantilever beam bonded with a piezoelectric active layer...

View Video Presentation: https://doi.org/10.2514/6.2022-0492.vid This paper presents a new composite adaptive control system for the control of wing rock motion. It is assumed that no parameters of the roll angle dynamics, including the control input coefficient, are known. The composite adaptive wing rock control system derived here is based on in...

The paper develops a composite identifier for the parameter estimation, and an indirect adaptive control law for output regulation of the chaotic Chua’s circuit. The Chua’s diode has polynomial nonlinearity. It is assumed that the model parameters are not known. First, gradient-based two parameter adaptation laws, using distinct prediction models,...

This paper proposes a new composite noncertainty-equivalence adaptive (CNCEA) control system for the attitude (roll, pitch, and yaw angle) control of a spacecraft in an orbit around a uniformly rotating asteroid based on the immersion and invariance (I&I) theory. For the design, it is assumed that the asteroid's gravitational parameters and the spa...

The paper presents a generalized composite noncertainty-equivalence adaptive control system for the control of a prototypical aeroelastic wing section using a single trailing-edge control surface. The plunge–pitch (two-degree-of-freedom) dynamics of this aeroelastic system include torsional pitch-axis nonlinearity. The open-loop system exhibits lim...

The circular restricted three-body problem (CR3BP) is important from the theoretical as well as a practical viewpoint. In this paper, the objective is to control a spacecraft along stable or unstable libration point orbits. For this purpose, a manifold of constant energy is specified. Then, a Hamiltonian-based state variable feedback control law is...

The paper presents composite noncertainty-equivalence adaptive control (NCEA) systems for the closed orbit and hovering control of spacecraft in the vicinity of a uniformly rotating asteroid. In this study, the asteroid’s mass and moment of inertia matrix, and the mass of the spacecraft are treated as unknown constant parameters. The objective is t...

The design of an attitude control system for an asteroid-orbiting satellite via immersion and invariance is the subject of this paper. It is assumed that the asteroid is rotating with a constant rate, and that the inertia parameters of the satellite and the coefficients in the spherical harmonic gravitational potential of the asteroid are not known...

This paper addresses the development of control systems for the orbit control of spacecraft around irregularly shaped rotating asteroids with uncertain parameters. The objective is to steer the spacecraft along prescribed orbits. First, a nonlinear adaptive law for orbit control was designed. This was followed by the design of a supertwisting adapt...

The development of an immersion-and invariance-based adaptive state variable feedback control law for the closed orbit and hovering control of spacecraft in the vicinity of asteroids is the subject of this paper. The celestial body is assumed to be rotating with constant angular velocity about a fixed axis. Also, it is assumed that the mass and mom...

The development of an adaptive control system for the attitude control of spacecraft orbiting around uniformly rotating asteroids is the subject of this paper. It is assumed that inertia parameters of spacecraft, and zonal and sectorial harmonic coefficients associated with the gravitational field of asteroid are not known. The objective is to cont...

This paper uses a composite finite time sliding model control for close formation flying of two aircraft.In close formation, lead aircraft produces vortex which is a complex function of relative coordinates of lead and wing aircraft.This vortex can be used by wing aircraft for reducing fuel consumption. Hence a tighter inner loop control and a oute...

Fixed Time Controller used For Controlling a Fighter Aircraft for Roll, Pitch and Yaw Tracking Control

The development of two nonlinear robust higher-order flight control systems for roll-coupled maneuvers of fighter aircraft with uncertain parameters is discussed in this article. The objective is to independently control the output variables (roll angle, pitch angle and sideslip angle) using aileron, elevator and rudder control surfaces. For a nomi...

This paper presents a finite-time sliding mode control system for the stabilization of a MIMO nonlinear aeroelastic system using leading-and trailing-edge control surfaces. The selected two-degree-of-freedom aeroelastic model includes uncertain parameters and gust loads. This wing model exhibits limit cycle oscillations (LCOs) beyond a critical fre...

The paper develops a noncertainty-equivalence adaptive (NCEA) spacecraft formation control system, using filtered signals, based on the immersion and invariance methodology. It is assumed that a target spacecraft is in an elliptic orbit and a follower satellite is moving around it. It is also assumed that the mass of the follower satellite is not k...

This paper develops a new nonlinear adaptive longitudinal autopilot for the control of missiles with control input constraint, in the presence of parametric uncertainties and external disturbance input. The objective here is to control the angle of attack of the missile. A saturating control law is derived for the trajectory control of the angle of...

This paper develops a new adaptive control system based on the immersion and invariance (I&I) theory for the wing rock motion control using state variable feedback. An I&I-based adaptive control system is designed for the regulation of the roll angle trajectory to a nonlinear terminal manifold. The trajectory evolving on this manifold converges to...

This paper presents the design of an ℒ1 adaptive control system for the stabilization of a two-dimensional aeroelastic system with structural nonlinearities and unsteady aerodynamics, using a single trailing-edge control surface. This model describes the plunge and pitch motion of a prototypical wing. It is assumed that its parameters are unknown a...

The paper presents a new nonlinear adaptive control system for the dive-plane control of multi-input multi-output submarine models with input constraints, in the presence of external disturbances. It is assumed that all the system parameters, except the signs of the principal minors of the input matrix, are unknown. The objective is to design an ad...

This paper presents the design of a higher-order sliding-mode control system for the three-axis attitude control of spacecraft using solar-radiation pressure in a finite time. The spacecraft, equipped with four solar plates, is assumed to be orbiting in an elliptic orbit. The nonlinear spacecraft model includes uncertain parameters and external-dis...

The development of an adaptive control system for the control of an uncertain aeroelastic system, in the presence of constraints on the leading- and trailing-edge control surface deflections, is the subject of this paper. The model describes the nonlinear plunge and pitch dynamics of a prototypical wing section. The open-loop system exhibits limit-...

The paper presents a robust nonlinear output feedback control system for the attitude control of satellites, with unstructured (unmodelled) dynamics in elliptic orbits, using solar radiation pressure. The nonaffine-in-control spacecraft model includes the gravity gradient torque, the control torque produced by two solar flaps, and external time-var...

This paper considers the synchronization of inferior olive neurons based on the adaptive control theory. The ION model treated here is the cascade connection of two nonlinear subsystems, termed ZW and UV subsystems. It is assumed that the structure of the nonlinear functions and certain parameters of the IONs are not known, and disturbance inputs a...

The wing rock (self-excited rolling motion) of aircraft flying at high angle of attack adversely affects the handling qualities and maneuverability. This paper presents new adaptation algorithms in finite (integral-algebraic) form for the wing rock control. The objective is to stabilize the rolling motion, despite parameter uncertainties. Two adapt...

A study was conducted to present the design of a second-order sliding-mode control system for the finite-time stabilization of an aeroelastic system, using a leading- and a trailing-edge control surface. The model included parametric uncertainties as well as external disturbance force and moment. A robust control system was designed for the trackin...

The development of a new immersion and invariance based output feedback adaptive attitude controller for satellites orbiting in elliptic orbits using solar radiation pressure is the subject of this paper. The satellite has two identical solar flaps for the pitch angle control. The nonaffine-in-control model includes gravity gradient torque and the...

In this paper, an L1 adaptive control system is designed for the control of a projectile fin. The rotational motion of the fin on the projectile is controlled by a flexible cantilever beam with a piezoelectric active layer, mounted inside the fin. The model includes time-varying disturbance input. In the closed-loop system, the applied voltage acco...

The development of a novel adaptive autopilot for the dive-plane control of multi-input multi-output submarines with unmodeled dynamics, based on the L-1 adaptive control theory, is the subject of this article. An L-1 adaptive autopilot is designed for the trajectory control of the depth and pitch angle using bow and stern hydroplanes. Interestingl...

The development of an L-1 adaptive control system for the control of satellites in elliptic orbits using solar radiation pressure is the subject of this article. The nonaffine-in-control spacecraft model includes the gravity gradient torque, the control torque produced by two solar flaps, and external time-varying disturbance torque. The objective...

Based on the adaptive control theory, a novel three-axis attitude control system for an axisymmetric spacecraft with uncertain dynamics moving in elliptic orbits, using solar radiation pressure, is derived. The nonaffine-in-control nonlinear spacecraft model includes the gravity gradient torque, the control torque produced by four solar flaps, and...

The development of a new robust finite-time control system, for the control of satellites in elliptic orbits with uncertain dynamics using solar radiation pressure (SRP), is the subject of this paper. The nonaffine-in-control spacecraft model includes the gravity gradient torque, the control torque produced by two solar flaps, and external time-var...

This paper presents the design of a higher-order sliding mode controller for finite-time stabilization of a multi-input multi-output nonlinear aeroelastic system with uncertain dynamics using leading- and trailing-edge control surfaces. The model describes the plunge and pitch dynamics of a prototypical wing section. It is assumed that the system p...

Aircraft flying at high angles of attack exhibit self-excited rolling motion (termed wing rock). This paper presents a noncertainty-equivalent adaptive control system for the wing-rock motion control via a Chebyshev neural network. The unmodeled nonlinearity of the system is approximated by a Chebyshev neural network using polynomials in roll angle...

The development of a control system for the suppression of aeroelastic vibration of a two-dimensional nonlinear wing-flap system based on the ℒ1 adaptive control theory is the subject of this paper. The prototypical aeroelastic wing section model considered here includes structural nonlinearity, parameter uncertainties and gust loads. For the purpo...

Aircraft with highly swept wings, flying at high angles of attack, exhibit selfexcited rolling motion (termed wing rock). This paper presents a noncertainty-equivalent adaptive control system for the wing rock motion control via a Chebyshev neural network. The unmodelled nonlinearity in the roll dynamics is approximated by a neural network with Che...

The paper presents a new adaptive output feedback satellite formation control system for satellites with uncertain relative dynamics. The dynamics of the follower satellite, relative to the leader spacecraft which is moving in an elliptic orbit, include disturbance forces and parameter uncertainty. It is assumed that only the relative position of t...

This paper presents a control system for the vibration suppression of a multi- input multi-output prototypical aeroelastic wing section based on the L1 adaptive control theory. The two-dimensional model of the system includes structural nonlinearity, parameter uncertainties and gust loads, and is controlled by trailing- and leading-edge control sur...

The development of an L1L1 adaptive control system for the control of an orbiting spacecraft with flexible appendages is the subject of this paper. It is assumed that the system parameters are unknown and that disturbance input is acting on the spacecraft. The spacecraft is controlled by a moment producing device located on the central rigid body....

Based on the attractive manifold design approach, a noncertainty-equivalent adaptive autopilot for the dive-plane control of submersibles, equipped with bow and stern hydroplanes, is developed. The parameters of the model are unknown and disturbance inputs are assumed to be present. The objective is to control the depth and pitch angle of the vehic...

The development of a new robust control system for the formation flying of satellites is the subject of this paper. The control system design is based on the internal model principle for the robust control of nonlinear systems. For simplicity, it is assumed that a leader satellite is revolving in an elliptical orbit, and a follower satellite is mov...

Based on the variable-structure model reference adaptive control theory, a new output feedback control system for the formation flying of satellites is designed. A leader satellite is moving on an elliptic orbit. The objective is to control a follower satellite so that it follows a prescribed path with respect to the leader satellite. The nonlinear...

Based on the variable structure model reference adaptive control theory, a new output feedback control system, for the formation flying of satellites, is designed. A leader satellite is moving in an elliptic orbit. The objective is to control a follower satellite so that it follows a prescribed path, with respect to the leader satellite. The nonlin...

This article presents a non-linear adaptive satellite formation control system basedon the tuning functions design method using output feedback. A leader spacecraft is orbiting in an elliptic orbit, and a follower satellite is in motion around it. It is assumed that unknown periodic disturbance forces as well as random disturbances are acting on th...

Inferior olive neurons (IONs) have rich dynamics and can exhibit stable, unstable, periodic, and even chaotic trajectories. This paper presents an analysis of bifurcation of periodic orbits of an ION when its two key parameters (a, μ) are varied in a two-dimensional plane. The parameter a describes the shape of the parabolic nonlinearity in the mod...

Based on the variable structure model reference adaptive control (VS-MRAC) theory, a new roll autopilot for the control of missiles is designed. The linear model of the missile includes airframe flexibility, sensor and actuator dynamics, and external disturbance input. It is assumed that the system parameters are not known. In the closed-loop syste...

The design of an adaptive control system for the synchronization of inferior olive neurons (IONs) is the subject of this paper. Clusters of inferior olive neurons in the olive-cerebellar system play an important role in providing synchronized motor control signals for the activation of large number of muscles. The orbits of IONs evolving from arbit...

The paper presents the design of a new non-certainty-equivalent adaptive (NCEA) control system for the control of chaos in Lorenz system for large parametric uncertainties, based on the immersion and invariance (I&I) theory. A backstepping procedure is used for the derivation of the NCEA law. This NCEA law differs from the traditional certainty-equ...

The article presents a new non-certainty-equivalent adaptive (NCEA) longitudinal autopilot for the control of a missile based on the immersion and invariance theory. The interest here is to control the angle of attack of the missile in the presence of large parametric uncertainties. For the derivation of the control law, a backstepping design proce...

The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signal...

This paper presents model reference adaptive control (MRAC) of underwater vehicle propelled by the Ionic polymer metal composite (IPMC) actuator. Trajectories of the vehicle are controlled by simultaneously controlling the bias and amplitude of the sinusoidal voltage applied to the IPMC actuator attached at the real end of the vehicle. It is assume...

Non-Certainty-Equivalent Adaptive Control of a Nonlinear Aeroelastic System The development of a non-certainty-equivalent adaptive control system for the control of a nonlinear aeroelastic system is the subject of this paper. The prototypical aeroelastic wing section considered here includes structural nonlinearity and a single control surface for...

This paper treats the question of noncertainty-equivalent adaptive control of a nonlinear aeroelastic system with leading- and trailing-edge control surfaces. The model describes the plunge and pitch dynamics of a prototypical wing section. It is assumed that all the system parameters, except the signs of principal minors of the input matrix, are u...

The development of a control system for the dive plane control of non-linear biorobotic autonomous underwater vehicles, equipped with pectoral-like fins, is the subject of this paper. Marine animals use pectoral fins for swimming smoothly. The fins are assumed to be oscillating with a combined pitch and heave motion and therefore produce unsteady c...

This paper presents a new noncertainty-equivalent adaptive control system for the control of a missile based on the immersion-and-invariance approach. The mathematical model of the missile represents the nonlinear longitudinal dynamics, and it is assumed that all the aerodynamic parameters (except the sign of a single control input gain) are not kn...

The article presents a new adaptive controller for attitude control of satellites using solar radiation pressure (SRP). The satellite has two identical solar flaps for pitch angle control. The model includes gravity gradient torque and the torque due to SRP. Unlike adaptive control design published in the literature for this model, here an adaptive...

This paper treats the question of global adaptive synchronization of inferior olive neurons (IONs) based on the immersion and invariance approach. The ION exhibits a variety of orbits as the parameter (termed the bifurcation parameter), which appears in its nonlinear functions, is varied. It is seen that once the bifurcation parameter exceeds a cri...

The paper treats the question of adaptive control of prototypical aeroelastic wing sections with structural nonlinearity based on the immersion and invariance approach. The chosen dynamic model describes the nonlinear plunge and pitch motion of a wing. A single control surface is used for the purpose of control. It is assumed that the model paramet...

This paper treats the question of adaptive control of prototypical aeroelastic wing sections with structural nonlinearity based on the immersion and invariance approach. The chosen dynamic model describes the nonlinear plunge and pitch motion of a wing. A single control surface is used for the purpose of control. It is assumed that the model parame...

This paper treats the question of servoregulation of autonomous underwater vehicles (AUVs) in the yaw plane using pectoral-like mechanical fins. The fins attached to the vehicle have oscillatory swaying and yawing motion. The bias angle of the angular motion of the fin is used for the purpose of control. Of course, the design approach considered he...

A multi-variable adaptive autopilot for the dive-plane control of submarines is designed. The vehicle is equipped with bow and stern hydroplanes for maneuvering. It is assumed that the system parameters are not known, and the disturbance force is acting on the vehicle. Based on a back-stepping design approach, an adaptive control law is derived for...

This paper presents a model reference adaptive control (MRAC) system for the dive plane control of a multi-input, multi-output (MIMO) autonomous underwater vehicle (AUV). The vehicle is equipped with a bow and a stern hydroplane for the purpose of control. It is assumed that the system parameters including the high-frequency gain matrix are unknown...

The development of neuroscience-based control methodologies and their integration with the high-lift unsteady hydrodynamics of control surfaces inspired by swimming and flying animals are the subjects of this paper. A biology-inspired rigid autonomous undersea vehicle called the biorobotic autonomous undersea vehicle (BAUV) has been developed at th...

The paper treats the design of (i) a variable structure control (VSC) system and (ii) an adaptive variable structure control (AVSC) system for three-dimensional trajectory control of a simplified F/A-18 model in the in presence of parametric uncertainties. For the nonlinear aircraft model, it is assumed that the high-frequency gain matrix associate...

This paper presents an integrated adaptive sliding mode flight control system for the roll-coupled maneuvers of aircraft. It is assumed that the parameters of the aircraft as well as its high-frequency gain matrix are unknown. Based on a backstepping design approach, an adaptive variable structure control law for the trajectory control of the roll...

This paper presents nonlinear adaptive and sliding-mode flight control systems for the roll-coupled maneuvers of aircraft. It is assumed that the parameters of the aircraft, as well as its high-frequency gain matrix, are unknown. Based on a backstepping design approach, nonlinear control laws (an adaptive variable structure control law and an adapt...

This article considers the control of a biorobotic autonomous underwater vehicle BAUV in the yaw plane using biologically inspired oscillatory pectoral-like fins of marine animals. The fins are assumed to be oscillating harmonically with a combined linear sway and angular yaw motion producing unsteady forces, which are used for fish-like control of...

The paper presents the design of a new simple adaptive system for the rotational maneuver and vibration suppression of an orbiting spacecraft with flexible appendages. A moment generating device located on the central rigid body of the spacecraft is used for the attitude control. It is assumed that the system parameters are unknown and the truncate...

The paper treats the question of adaptive control of orbiting spacecraft with flexible appendages. The spacecraft consists of a rigid satellite body and two flexible appendages and is rotating in a circular orbit. The finite dimensional representation of the flexible spacecraft is assumed to be of arbitrary order and the model parameters (including...

The paper treats the question of suboptimal dive plane control of autonomous underwater vehicles (AUVs) using the state-dependent Riccati equation (SDRE) technique. The SDRE method provides an effective mean of designing nonlinear control systems for minimum as well as nonminimum phase AUV models. It is assumed that the hydrodynamic parameters of t...

This paper treats the question of adaptive control of a biorobotic autonomous underwater vehicle (BAUV) in the yaw plane using biologically-inspired pectoral-like fins. The fins are assumed to be oscillating harmonically with a combined linear (sway) and angular (yaw) motion. The bias (mean) angle of the angular motion of the fin is used as a contr...

The paper treats the question of robust control of chaos in Chua’s circuit based on the internal model principle. The Chua’s diode has polynomial non-linearity and it is assumed that the parameters of the circuit are not known. A robust control law for the asymptotic regulation of the output (node voltage) along constant and sinusoidal reference tr...