Hardware-in-the-loop evaluation of an LPV sliding mode fixed control allocation scheme on the MuPAL-α research aircraft

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordThis paper develops a sliding mode fault tolerant control scheme based on an LPV system representation of the plant. The scheme involves a control allocation component, which is capable of fully utilizing the available actuators in the face of actuator faults. In this paper, information about the actuator faults is assumed not to be available and therefore a fixed control allocation structure is utilised in the event of faults. The proposed scheme is validated using the Japanese Aerospace Exploration Agency's Multi-Purpose Aviation Laboratory (MuPAL-α) research aircraft. This paper describes initial hardware-in-the-loop (HIL) tests which serve as a precursor to upcoming real flight tests. The validation results show good lateral-directional state tracking performance in the fault free case with no visible performance degradation in the presence of (aileron) faults. Successful HIL tests demonstrate the potential of the proposed scheme which will be flight tested later this year.European CommissionJapan New Energy and Industrial Technology Development Organizatio

Regions of robust relative stability for PI controllers and LTI plants with unstructured multiplicative uncertainty: A second-order-based example

This example-oriented article addresses the computation of regions of all robustly relatively stabilizing Proportional-Integral (PI) controllers under various robust stability margins α for Linear Time-Invariant (LTI) plants with unstructured multiplicative uncertainty, where the plant model with multiplicative uncertainty is built on the basis of the second-order plant with three uncertain parameters. The applied graphical method, adopted from the authors’ previous work, is grounded in finding the contour that is linked to the pairs of P–I coefficients marginally fulfilling the condition of robust relative stability expressed using the H∞ norm. The illustrative example in the current article emphasizes that the technique itself for plotting the boundary contour of robust relative stability needs to be combined with the precondition of the nominally stable feedback control system and with the line for which the integral parameter equals zero in order to get the final robust relative stability regions. The calculations of the robust relative stability regions for various robust stability margins α are followed by the demonstration of the control behavior for two selected controllers applied to a set of members from the family of plants.College of Polytechnics Jihlava, (INT/2022/0002); Grantová Agentura České Republiky, GA ČR, (21–45465L)Czech Science Foundation (GACR) [21-45465L]; College of Polytechnics Jihlava [INT/2022/0002

Development and application of sliding mode LPV fault reconstruction schemes for the ADDSAFE

Copyright © 2014 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Control Engineering Practice. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Control Engineering Practice Vol. 31 (2014), DOI: 10.1016/j.conengprac.2014.05.003This paper describes the development and the evaluation of a robust sliding mode observer fault detection scheme applied to an aircraft benchmark problem as part of the ADDSAFE project. The ADDSAFE benchmark problem which is considered in this paper is the yaw rate sensor fault scenario. A robust sliding mode sensor fault reconstruction scheme based on an LPV model is presented, where the fault reconstruction signal is obtained from the so-called equivalent output error injection signal associated with the observer. The development process includes implementing the design using AIRBUS׳s the so-called SAO library which allows the automatic generation of flight certifiable code which can be implemented on the actual flight control computer. The proposed scheme has been subjected to various tests and evaluations on the Functional Engineering Simulator conducted by the industrial partners associated with the ADDSAFE project. These were designed to cover a wide range of the flight envelope, specific challenging manoeuvres and realistic fault types. The detection and isolation logic together with a statistical assessment of the FDD schemes are also presented. Simulation results from various levels of FDD developments (from tuning, testing and industrial evaluation) show consistently good results and fast detection times.European Union (FP7-233815

Generation of Optimal Linear Parametric Models for LFT-based Robust Stability Analysis and Control Design

We present a general approach to generate a linear parametric state-space model, which approximates a nonlinear system with high accuracy. It is optimally suited for LFT-based robust stability analysis and control design. At the beginning a Jacobian-based linearization is applied to gernerate a set of linearized state-space systems describing the local behavior of the nonlinear plant about the corresponding equilibrium points. These models are then approximated using multivariable polynominal fitting techniques in combination with global optimization. Tthe objective is to find a linear parametric model, which allows the transformation into a Linear Fractional Representation (LFR) of least possible order. A gab metric constraint is included during the optimization in order to guarantee a specified accuracy of the tarnsfer function of the linear parametric model. The effectiveness of the proposed method is demonstrated by a robust stability analysis for a nonlinear generic missile model

D04.05 - Feasibility mock-ups of feedback schedulers

Control and computation co-design deals with the interaction between feedback control laws design and their implementation on a real execution resource. Control design is often carried out in the framework of continuous time, or under the assumption of ideal sampling with equidistant intervals and known delays. Implementation on a real-time execution platform introduces many timing uncertainties and distortions to the ideal timing scheme, e.g. due to variable computation durations, complex preemption patterns between concurrent activities, uncertain network induced communication delays or occasional data loss. Analyzing, prototyping, simulating and guaranteeing the safety of complex control systems are very challenging topics. Models are needed for the mechatronic continuous system, for the discrete controllers and diagnosers, and for network behavior. Real-time properties (task response times) and the network Quality of Service (QoS) influence the controlled system properties (Quality of Control, QoC). To reach effective and safe systems it is not enough to provide theoretic control laws and leave programmers and real-time systems engineers just do their best to implement the controllers. This report first describes, through the detailed design of a quadrotor drone controller, the main features of {\sc Orccad}, an integrated development environment aimed to bridge the gap between advanced control design and real-time implementation. Besides control design and implementation, a real-time (hardware-in-the-loop) simulation has been designed to assess the control design with a simulated target rather than with the real plant. Using this HIL structure, several experiments using flexible real-time control features are reported, namely Kalman filters subject to data loss, control under (m,k)-firm constraints, control with varying sampling rates and feedback scheduling using the MPC approach