High-order derivative fusion estimation of rotorcraft angular rate

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Changwu Liu ◽  
Haowen Wang ◽  
Chen Jiang
Keyword(s):  
Flight Control ◽  
Angular Rate ◽  
Flight Test ◽  
High Order ◽  
Angular Motion ◽  
High Order Derivative ◽  
Content Type ◽  
Maneuvering Flight ◽  
Update Rate ◽  
Derivatives Of

Purpose The paper aims at developing a novel algorithm to estimate high-order derivatives of rotorcraft angular rates to break the contradiction between bandwidth and filtering performance because high-order derivatives of angular rates are crucial to rotorcraft control. Traditional causal estimation algorithms such as digital differential filtering or various tracking differentiators cannot balance phase-lead angle loss and high-frequency attenuation performance of the estimated differentials under the circumstance of strong vibration from the rotor system and the rather low update rate of angular rates. Design/methodology/approach The algorithm, capable of estimating angular rate derivatives to maximal second order, fuses multiple attitude signal sources through a first-proposed randomized angular motion maneuvering model independent of platform dynamics with observations generated by cascaded tracking differentiators. Findings The maneuvering flight test on 5-kg-level helicopter and the ferry flight test on 230-kg-level helicopter prove such algorithm is feasible to generate higher signal to noise ratio derivative estimation of angular rates than traditional differentiators in regular flight states with enough bandwidth for flight control. Research limitations/implications The decrease of update rate of input attitude signals will weaken the bandwidth performance of the algorithm and higher sampling rate setting is recommended. Practical implications Rotorcraft flight control researchers and engineers would benefit from the estimation method when implementing flight control laws requiring angular rate derivatives. Originality/value A purely kinematic randomized angular motion model for flight vehicle is first established, combining rigid-body Euler kinematics. Such fusion algorithm with observations generated by cascaded tracking differentiators to estimate angular rate derivatives is first proposed, realized and flight tested.

Flight test of fault-tolerant flight control system using simple adaptive control with PID controller

2018 ◽  
Vol 90 (1) ◽  
pp. 210-218 ◽  
Author(s):  
Hidenobu Matsuki ◽  
Taishi Nishiyama ◽  
Yuya Omori ◽  
Shinji Suzuki ◽  
Kazuya Masui ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Flight Control ◽  
Pid Controller ◽  
Control Method ◽  
Fault Tolerant ◽  
Flight Test ◽  
Static Stability ◽  
Flight Tests ◽  
Content Type ◽  
Sudden Reduction

Purpose This paper aims to demonstrate the effectiveness of a fault-tolerant flight control method by using simple adaptive control (SAC) with PID controller. Design/methodology/approach Numerical simulations and flight tests are executed for pitch angle and roll angle control of research aircraft MuPAL-α under the following fault cases: sudden reduction in aileron effectiveness, sudden reduction in elevator effectiveness and loss of longitudinal static stability. Findings The simulations and flight tests reveal the effectiveness of the proposed SAC with PID controller as a fault-tolerant flight controller. Practical implications This research includes implications for the development of vehicles’ robustness. Originality/value This study proposes novel SAC-based flight controller and actually demonstrates the effectiveness by flight test.

Signal reconstruction and disturbance observer-based fault-tolerant control for civil aircrafts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xinjian Ma ◽  
Shiqian Liu ◽  
Huihui Cheng ◽  
Weizhi Lyu
Keyword(s):  
Flight Control ◽  
Disturbance Observer ◽  
Fault Tolerant ◽  
Signal Reconstruction ◽  
Angular Rate ◽  
Sensor Faults ◽  
Sensor Signal ◽  
Sensor Fault ◽  
Content Type ◽  
Civil Aircraft

Purpose This paper aims to focus on the sensor fault-tolerant control (FTC) for civil aircraft under exterior disturbance. Design/methodology/approach First, a three-step cubature Kalman filter (TSCKF) is designed to detect and isolate the sensor fault and to reconstruct the sensor signal. Meanwhile, a nonlinear disturbance observer (NDO) is designed for disturbance estimation. The NDO and the TSCKF are combined together and an NDO-TSCKF is proposed to solve the problem of sensor faults and bounded disturbances simultaneously. Furthermore, an FTC scheme is designed based on the nonlinear dynamic inversion (NDI) and the NDO-TSCKF. Findings The method is verified by a Cessna 172 aircraft model under bias gyro fault and constant angular rate disturbance. The proposed NDO-TSCKF has the ability of signal reconstruction and disturbance estimation. The proposed FTC scheme is also able to solve the sensor fault and disturbance simultaneously. Research limitations/implications NDO-TSCKF is the novel algorithm used in sensor signal reconstruction for aircraft. Then, disturbance observer-based FTC can improve the flight control system performances when the system with faults. Practical implications The NDO-TSCKF-based FTC scheme can be used to solve the sensor fault and exterior disturbance in flight control. For example, the bias gyro fault with constant angular rate disturbance of a civil aircraft is studied. Social implications Signal reconstruction for critical sensor faults and disturbance observer-based FTC for civil aircraft are useful in modern civil aircraft design and development. Originality/value This is the research paper studies on the signal reconstruction and FTC scheme for civil aircraft. The proposed NDO-TSCKF is better than the current reconstruction filter because the failed sensor signal can be reconstructed under disturbances. This control scheme has a better fault-tolerant capability for sensor faults and bounded disturbances than using regular NDI control.

Design and Flight Test of a Cable Angle Feedback Flight Control System for the RASCAL JUH-60 Helicopter

2014 ◽  
Vol 59 (4) ◽  
pp. 1-15 ◽  
Author(s):  
Christina M. Ivler ◽  
J. David Powell ◽  
Mark B. Tischler ◽  
Jay W. Fletcher ◽  
Carl Ott
Keyword(s):  
Control System ◽  
Flight Control ◽  
Flight Test ◽  
Feedback System ◽  
Military Operations ◽  
Flight Control System ◽  
Handling Qualities ◽  
Maneuvering Flight ◽  
Rate Feedback ◽  
Tailored Approach

The ability of a helicopter to carry externally slung loads makes it very versatile for many civil and military operations. However, the piloted handling qualities of the helicopter are degraded by the presence of the slung load. A control system is developed that uses measurements of the slung load motions as well as conventional fuselage feedback to improve the handling qualities for hover/low-speed operations. Prior research has shown a fundamental trade-off between load damping and piloted handling qualities for a feedback control system with cable angle/rate feedback. A new task-tailored approach proposed and implemented herein uses a method of switching between a load damping mode and a piloted handling qualities mode. These modes provide appropriate load feedback depending on the piloting task and flight regime. This provides improved handling qualities for maneuvering flight and for improved precision load control at hover. A new mission task element for precision load placement is developed (for possible inclusion into ADS-33E-PRF) to test the ability of the cable feedback system to improve load placement task performance. The improvements provided by this control system are demonstrated in a piloted flight test on the JUH-60A RASCAL fly-by-wire helicopter. The average load set-down time was reduced by a factor of two for the 1000-lb load on a 56-ft sling.

Numerical properties of equations involving high-order derivatives of pressure with respect to volume

2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Claude Leibovici ◽  
Dan Nichita
Keyword(s):  
Equation Of State ◽  
Equations Of State ◽  
High Order ◽  
Order Derivative ◽  
High Order Derivative ◽  
Nodal Curves ◽  
Solution Of Equations ◽  
Derivatives Of ◽  
Two Parameter

AbstractThis paper presents some unexpected features related to the solution of equations containing a high-order derivative of pressure with respect to volume equated to zero. For pure components, such equations define, in the pressure-temperature plane, nodal curves similar in shape to mixture spinodal curves. The analysis was made for a general form of two-parameter cubic equations of state and various numerical aspects for the Redlich-Kwong equation of state are exemplified.

scholarly journals New Formulae for the High-Order Derivatives of Some Jacobi Polynomials: An Application to Some High-Order Boundary Value Problems

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
W. M. Abd-Elhameed
Keyword(s):  
Galerkin Method ◽  
Boundary Value Problems ◽  
Chebyshev Polynomials ◽  
Hypergeometric Functions ◽  
Jacobi Polynomials ◽  
Boundary Value ◽  
High Order ◽  
Sixth Order ◽  
Special Cases ◽  
Derivatives Of

This paper is concerned with deriving some new formulae expressing explicitly the high-order derivatives of Jacobi polynomials whose parameters difference is one or two of any degree and of any order in terms of their corresponding Jacobi polynomials. The derivatives formulae for Chebyshev polynomials of third and fourth kinds of any degree and of any order in terms of their corresponding Chebyshev polynomials are deduced as special cases. Some new reduction formulae for summing some terminating hypergeometric functions of unit argument are also deduced. As an application, and with the aid of the new introduced derivatives formulae, an algorithm for solving special sixth-order boundary value problems are implemented with the aid of applying Galerkin method. A numerical example is presented hoping to ascertain the validity and the applicability of the proposed algorithms.

A self-developed indoor three-dimensional pedestrian localization platform based on MEMS sensors

Sensor Review ◽  
2015 ◽  
Vol 35 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Shengbo Sang ◽  
Ruiyong Zhai ◽  
Wendong Zhang ◽  
Qirui Sun ◽  
Zhaoying Zhou
Keyword(s):  
Low Cost ◽  
Angular Rate ◽  
Three Dimensional ◽  
Dead Reckoning ◽  
Rate Data ◽  
Mems Sensors ◽  
Micro Electro Mechanical Systems ◽  
Content Type ◽  
Position Errors ◽  
Low Performance

Purpose – This study aims to design a new low-cost localization platform for estimating the location and orientation of a pedestrian in a building. The micro-electro-mechanical systems (MEMS) sensor error compensation and the algorithm were improved to realize the localization and altitude accuracy. Design/methodology/approach – The platform hardware was designed with common low-performance and inexpensive MEMS sensors, and with a barometric altimeter employed to augment altitude measurement. The inertial navigation system (INS) – extended Kalman filter (EKF) – zero-velocity updating (ZUPT) (INS-EKF-ZUPT [IEZ])-extended methods and pedestrian dead reckoning (PDR) (IEZ + PDR) algorithm were modified and improved with altitude determined by acceleration integration height and pressure altitude. The “AND” logic with acceleration and angular rate data were presented to update the stance phases. Findings – The new platform was tested in real three-dimensional (3D) in-building scenarios, achieved with position errors below 0.5 m for 50-m-long route in corridor and below 0.1 m on stairs. The algorithm is robust enough for both the walking motion and the fast dynamic motion. Originality/value – The paper presents a new self-developed, integrated platform. The IEZ-extended methods, the modified PDR (IEZ + PDR) algorithm and “AND” logic with acceleration and angular rate data can improve the high localization and altitude accuracy. It is a great support for the increasing 3D location demand in indoor cases for universal application with ordinary sensors.

scholarly journals On accurate high-order numerical derivatives computations for quantum chemistry purposes

2018 ◽  
Keyword(s):  
Quantum Chemistry ◽  
Finite Field ◽  
Numerical Differentiation ◽  
Field Method ◽  
High Order ◽  
Parameter Choice ◽  
Derivatives Of ◽  
Finite Field Method ◽  
Account Electron

Various molecular parameters in quantum chemistry could be computed as derivatives of energy over different arguments. Unfortunately, it is quite complicated to obtain analytical expression for characteristics that are of interest in the framework of methods that account electron correlation. Especially it relates to the coupled cluster (CC) theory. In such cases, numerical differentiation comes to rescue. This approach, like any other numerical method has empirical parameters and restrictions that require investigation. Current work is called to clarify the details of Finite-Field method usage for high-order derivatives calculation in CC approaches. General approach to the parameter choice and corresponding recommendations about numerical steadiness verification are proposed. As an example of Finite-Field approach implementation characterization of optical properties of fullerene passing process through the aperture of carbon nanotorus is given.

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