Active Disturbance Rejection Based Robust Trajectory Tracking Controller Design in State Space

This paper proposes a new Active Disturbance Rejection based robust trajectory tracking controller design method in state space. It can compensate not only matched but also mismatched disturbances. Robust state and control input references are generated in terms of a fictitious design variable, namely differentially flat output, and the estimations of disturbances by using Differential Flatness and Disturbance Observer. Two different robust controller design techniques are proposed by using Brunovsky canonical form and polynomial matrix form approaches. The robust position control problem of a two mass-spring-damper system is studied to verify the proposed robust controllers.Comment: Accepted by ASME Journal of Journal of Dynamic Systems, Measurement, and Control in 201

Symbolic Ingredient Branding to Promote Premier Locally Produced Material in Global Consumer Market: A Case of American Wild Alligator Leather

Co-branding is one of the most commonly used strategies to promote new brands and maximize the market potential of established brands (Keller, 1993; Rooney, 1995). Ingredient branding (InBranding) is a popular co-branding strategy involving host and ingredient brands to develop an ingredient branding offering (IBO). Such co-branding is a win-win strategy for both host and ingredient brands working together to expand markets (Norris, 1992). This exploratory conceptual study focuses on the premier fashion component, American wild alligator leather

Study on the Single Scattering of Elastic Waves by a Cylindrical Fiber with a Partially Imperfect Bonding Using the Collocation Point Method

The single scattering of P- and SV-waves by a cylindrical fiber with a partially imperfect bonding to the surrounding matrix is investigated, which benefits the characterization of the behavior of elastic waves in composite materials. The imperfect interface is modelled by the spring model. To solve the corresponding single scattering problem, a collocation point (CP) method is introduced. Based on this method, influence of various aspects of the imperfect interface on the scattering of P- and SV-waves is studied. Results indicate that (i) the total scattering cross section (SCS) is almost symmetric about the axis α=π/2 with respect to the location (α) of the imperfect interface, (ii) imperfect interfaces located at α=0 and α=π highly reduce the total SCS under a P-wave incidence and imperfect interfaces located at α=π/2 reduce the total SCS most significantly under SV-incidence, and (iii) under a P-wave incidence the SCS has a high sensitivity to the bonding level of imperfect interfaces when α is small, while it becomes more sensitive to the bonding level when α is larger under SV-wave incidence

Disturbance rejection for nonlinear uncertain systems with output measurement errors: Application to a helicopter model

As a virtual sensor, disturbance observer provides an alternative approach to reconstruct lumped disturbances (including external disturbances and system uncertainties) based upon system states/outputs measured by physical sensors. Not surprisingly, measurement errors bring adverse effects on the control performance and even the stability of the closed-loop system. Toward this end, this paper investigates the problem of disturbance observer based control for a class of disturbed uncertain nonlinear systems in the presence of unknown output measurement errors. Instead of inheriting from the estimation-error-driven structure of Luenberger type observer, the proposed disturbance observer only explicitly uses the control input. It has been proved that the proposed method endows the closed-loop system with strong robustness against output measurement errors and system uncertainties. With rigorous analysis under the semiglobal stability criterion, the guideline of gain choice based upon the proposed structure is provided. To better demonstrate feature and validity of the proposed method, numerical simulation and comparative experiments of a helicopter model are implemented

Generalized Dynamic Predictive Control for Nonlinear Systems Subject to Mismatched Disturbances with Application to PMSM Drives

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This paper investigates a generalized dynamic predictive control (GDPC) strategy with a novel autonomous tuning mechanism of the horizon for a class of nonlinear systems subject to mismatched disturbances. As a new incremental function for the predictive control method, the horizon can be determined autonomously with respect to the system working conditions, instead of selecting a fixed value via experience before, which is able to effectively improve the control performance optimization ability to a certain extent considering different system perturbation levels. To this aim, firstly, a non-recursive composite control framework is constructed based on a series of disturbance observations via higher-order sliding modes. Secondly, by designing a simple one-step scaling gain update mechanism into the receding horizon optimization, the horizon can be therefore adaptively tuned according to its real-time practical operating conditions. A three-order numerical simulation and a typical engineering application of permanent magnet synchronous motor (PMSM) drive system are carried out to demonstrate the effectiveness and conciseness of the proposed GDPC method

Catheter-directed thrombolysis for patients with acute lower extremity deep vein thrombosis: a meta-analysis

Objetivos: Evaluar estudios de series de casos y evaluar cuantitativamente los efectos de la trombólisis dirigida por catéter (TDC) y comparar la eficacia entre la TDC y anticoagulación en pacientes con trombosis venosa profunda (TVP) aguda de las extremidades inferiores para el tratamiento futuro. Métodos: Se realizaron búsquedas en bases de datos relevantes, incluyendo PubMed, Embase, Cochrane, Ovid MEDLINE y Scopus hasta enero de 2017. Los criterios de inclusión se aplicaron a pacientes seleccionados con TVP aguda de extremidad inferior tratados con TDC o comparados con TDC y anticoagulación. En estudios de series de casos, las estimaciones agrupadas de los resultados de eficacia para la tasa de patencia, la lisis completa, la retrombosis y el síndrome postrombótico (SPT) se calcularon a través de los estudios. En estudios que compararon la TDC con la anticoagulación, se calculó el resumen de las razónes de posibilidades (RP). Resultados: 25 artículos (seis que comparan TDC con anticoagulación y 19 series de casos) que incluyeron 2254 pacientes qienes cumplieron los criterios de elegibilidad. En los estudios de series de casos, los resultados agrupados fueron: tasa de patencia 0,87 (IC 95%: 0,85; 0,89), lisis completa 0,58 (IC 95%: 0,40; 0,75), retrombosis 0,11 (IC 95%: 0,06; 17,0), SPT 0,10 (IC 95%: 0,08; 0,12). Seis estudios que compararon los resultados de eficacia entre la TDC y anticoagulación mostraron que la TDC se asoció con una reducción de SPT (RP 0,38; IC 95%: 0,26; 0,55; pObjectives: To evaluate case series studies that quantitatively assess the effects of catheter-directed thrombolysis (CDT) and compare the efficacy of CDT and anticoagulation in patients with acute lower extremity deep vein thrombosis (DVT). Methods: Relevant databases, including PubMed, Embase, Cochrane, Ovid MEDLINE and Scopus, were searched through January 2017. The inclusion criteria were applied to select patients with acute lower extremity DVT treated with CDT or with anticoagulation. In the case series studies, the pooled estimates of efficacy outcomes for patency rate, complete lysis, rethrombosis and post-thrombotic syndrome (PTS) were calculated across the studies. In studies comparing CDT with anticoagulation, summary odds ratios (ORs) were calculated. Results: Twenty-five articles (six comparing CDT with anticoagulation and 19 case series) including 2254 patients met the eligibility criteria. In the case series studies, the pooled results were a patency rate of 0.87 (95% CI: 0.85-0.89), complete lysis 0.58 (95% CI: 0.40-0.75), rethrombosis 0.11 (95% CI: 0.06-0.17) and PTS 0.10 (95% CI: 0.08-0.12). Six studies comparing the efficacy outcomes of CDT and anticoagulation showed that CDT was associated with a reduction of PTS (OR 0.38, 95%CI 0.26-0.55, pObjetivos: Avaliar os estudos de séries de casos e avaliar quantitativamente os efeitos da trombólise dirigida por cateter (TDC) e comparar a eficácia entre TDC e anticoagulação nos pacientes com trombose venosa profunda aguda das extremidades inferiores (TVP) para tratamento futuro. Métodos: Foram pesquisadas as seguintes bases de dados relevantes: PubMed, Embase, Cochrane, Ovid MEDLINE e Scopus​. Os critérios de inclusão foram aplicados para pacientes selecionados com TVP aguda de extremidades inferiores tratados com TDC comparada a TDC com anticoagulação. Nos estudos de série de casos, as estimativas agrupadas de resultados de eficácia para a taxa de permeabilidade, lise completa, retrombose e síndrome pós-trombótica (SPT) foram calculadas em todos os estudos. Em estudos comparando TDC com anticoagulação, foi calculada a razão de chance de resumo (summary odds ratio - OR). Resultados: Vinte e cinco artigos (seis comparando TDC com anticoagulação e 19 séries de casos), incluindo 2.254 pacientes, preencheram os critérios de elegibilidade. Nos estudos da série de casos, os resultados agrupados foram: taxa de permeabilidade 0,87 (IC95%: 0,85-0,89), lise completa 0,58 (IC95%: 0,40-0,75), e retrombose 0,11 (IC95%: 0,06-0,17), SPT 0,10 (IC95%: 0,08-0,12). Seis estudos que compararam os resultados de eficácia entre TDC e anticoagulação mostraram que TDC foi associada à redução da SPT (OR 0,38; IC95%: 0,26-0,55;

A non-recursive C1 adaptive stabilization methodology for nonlinearly parameterized uncertain nonlinear systems

A non-recursive adaptive stabilization method, under a semi-global stability objective, is studied in this paper for a class of nonlinearly parameterized uncertain nonlinear systems. By incorporating the homogeneous system theory and a non-recursive synthesis approach, the resulting adaptive stabilizing control scheme can now be constructed within a novel one-step design framework. Employing an adaption law to online determine the time-varying scaling gain, both the controller expression and gain tuning mechanism are much simpler than related existing recursive design approaches. It is also shown that the proposed method will be applicable to a class of non-triangular nonlinear uncertain systems. Besides, considering a smooth control case, a condition of the system nonlinearities is sufficient for deriving an effective linear adaptive stabilizing control scheme. Examples and numerical simulations are provided to demonstrate both the simplicity and effectiveness of the proposed control algorithms