Dynamic Integral Sliding Mode for MIMO Uncertain Nonlinear Systems

Qudrat Khan,Aamer Iqbal Bhatti,Sohail Iqbal,Mohammad Iqbal 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.1

In this paper the authors propose a novel sliding mode control methodology for Multi-Input and Multi-Output (MIMO) uncertain nonlinear systems. The proposed approach synthesizes dynamic sliding mode and integral sliding mode control strategies into dynamic integral sliding mode. The new control laws establish sliding mode without reaching phase with the use of an integral sliding manifold. Consequently, robustness against uncertainties increases from the very beginning of the process. Fur-thermore, the control laws considerably alleviate chattering along the switching manifold. In addition, the performance of the controller boost up in the presence of uncertainties. A comprehensive compara-tive analysis carried out with dynamic sliding mode control and integral sliding mode control demon-strates superiority of the newly designed control law. A chatter free regulation control of two uncertain nonlinear systems with improved performance in the presence of uncertainties ensures the robustness of the proposed dynamic integral sliding mode controller.

Cold Stress Evaluation among Maize (Zea mays L.) Inbred Lines in Different Temperature Conditions

( Muhammad Qudrat Ullah Farooqi ),( Ju Kyong Lee ) 한국육종학회 2016 Plant Breeding and Biotechnology Vol.4 No.3

Maize (Zea mays L.) is a crop in a tropical region which resists growing under sensitive temperature. This study was conducted to evaluate the performance of Canadian maize inbred lines under controlled cold stress conditions (5 ℃, 10 ℃, and 23 ℃). Data were recorded by measuring germination rate, index, root length, and seed vigour index values. Five higher and three lower tolerant inbred lines were shortlisted. The data were analyzed using analysis of variance, while mean values were compared using Tukey`s Honest Significant Difference Test at α=0.05 and at α=0.01. Using Genstat software, correlation was done. A strong correlation (P<0.05) was found between germination rate and germination index under all stress conditions. Root length and vigour index were also strongly correlated with germination rate under 5 ℃ stress condition and compared to 10 ℃ and 23 ℃ stress conditions. Our results suggested that five (CO439, CO438, CO450, CO435, and CO445) among 22 maize inbred lines performed better under 5 ℃ cold stress condition and thus had the potential to develop maize hybrids to increase grain yield under environmentally stressful conditions in South Korea.

Genetic diversity and relationships among rice accessions (Oryza Sativa L.) of cultivated and weedy types using CACTA-TD and AFLP markers

Rahul Vasudeo Ramekar,Muhammad Qudrat Ullah Farooqi,Kyu Jin Sa,Kyong-Cheul Park,Ju Kyong Lee 한국육종학회 2015 한국육종학회 심포지엄 Vol.2015 No.07

For understanding the genetic diversity and genetic relationship between cultivated and weedy types, we evaluated genetic variation of 80 accessions of rice (O. Sativa). This included 42 cultivated accessions and 38 weedy accessions with the help of AFLP and CACTA-TD. A total of 542 loci were analyzed (255 for AFLP and 287 for CACTA-TD) of which AFLP markers exhibited 75% of polymorphism and transposon based CACTA-TD markers exhibited 93% of polymorphism. The average genetic diversity value for all 80 accessions, using AFLP markers was 0.226 (Cultivated – 0.210; Weedy 0.241) and based on CACTA-TD markers was 0.281 (Cultivated – 0.294; Weedy 0.269). A UPGMA phylogenetic tree revealed three major groups for both the marker system. The average polymorphic content value obtained with AFLP and CACTA-TD markers were 0.21 and 0.232, Effective multiplex ratio (AFLP – 47.50; CACTA-TD – 66.75), Marker Index (AFLP – 9.94; CACTA-TD – 21.13) and Resolving power (AFLP – 19.53; CACTA-TD – 34.62) indicated that the CACTA-TD markers were relatively efficient than AFLP markers.

Robust Backstepping Sliding Mode Control Design for a Class of Underactuated Electro–Mechanical Nonlinear Systems

Safeer Ullah,Qudrat Khan,Adeel Mehmood,Aamer Iqbal Bhatti 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

This paper presents a backstepping sliding mode control (BSMC) scheme for uncertain underactuated nonlinear systems. Since, underactuated electro-mechanical nonlinear systems (UEMNS) operate under the fewer number of inputs than the degree of freedom, therefore, the control of such systems remains a complex task. In this work, a class of UEMNS is considered which can be transformed into the so-called regular form. In the design process, these UEMNS are frst transformed into regular form. In this form, the systems are properly subdivided into series cascaded blocks in which the one of the blocks is indirectly driven by the applied control input whereas the second block is directly controlled by the control input. This structure is apparently suitable for backstepping design. Hence, all the controller steps are designed via the proposed backstepping sliding mode technique. The step by step stability is proved rigorously by considering the Lyapunov approach. In term of benefts, this designed control law provides low-frequency vibration as compared to conventional SMC along with robust performance in the presence of matched uncertainties. This claim is verifed via the numerical simulation results of the cart-pendulum system. For further confrmation, these results are also compared with the standard literature results to demonstrate the benefts and efectiveness of the aforesaid control scheme for such class.

Performance of High-Voltage Polymeric Insulators Under Simulated Environmental Conditions in Desert Areas of Southern Libya

Abdelati Jermi,Yadong He,Qudrat Ullah Khan 한국전기전자재료학회 2018 Transactions on Electrical and Electronic Material Vol.19 No.1

One of the primary aims for any type of electrical utility is the minimization of active power losses. In terms of cost andreliability, high-voltage (HV) polymeric insulators are used worldwide. This study considered the performance and reliabilityof insulators under accelerated aging conditions with the simulation of the environmental conditions of southern Libya. These issues with insulators have been a major problem for power utilities in southern Libya for many years. In order tocheck the HV performance, the International Electrochemical Commission (IEC) Standard-61109 was used to age the twoinsulators. Other samples were maintained under the accelerated aging conditions, i.e., the inland temperature and the actualultraviolet radiation intensity; the two thermoelectric stresses and UV radiations were applied on the polymeric insulators,aged as per the IEC standard and modifi ed IEC standards, simulating the desert of Libya. The experimental data revealedthat the thermoplastic insulators and their dielectric response under the tested thermoelectric cum ultraviolet-irradiationsperformed better than the silicone rubber insulators. Hence, the assessment of the data provided vital information regardingthe stability and performance of these composite insulators which allows for an informed decision about the best materialsfor the application.

Robust Integral Sliding Mode Control Design for Stability Enhancement of Under-actuated Quadcopter

Safeer Ullah,Adeel Mehmood,Qudrat Khan,Sakhi Rehman,Jamshed Iqbal 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7

In this paper, a robust backstepping integral sliding mode control (RBISMC) technique is designed for the flight control of a quadcopter, which is an under-actuated nonlinear system. First, the mathematical model of this highly coupled and under-actuated system is described in the presence of dissipative drag forces. Second, a robust control algorithm is designed for the derived model to accurately track the desired outputs while ensuring the stability of attitude, altitude and position of the quadcopter. A step by step mathematical analysis, based on the Lyapunov stability theory, is performed that endorses the stability of both the fully-actuated and under-actuated subsystems of the aforementioned model. The comparison of proposed RBISMC control algorithm, with fraction order integral sliding mode control (FOISMC), affirms the enhanced performance in terms of faster states convergence, improved chattering free tracking and more robustness against uncertainties in the system.

Characterization and Thermal Degradation Study of Carbonization the Polyimide (PMDA/ODA)/Fe Composite Films

Fathi Etaher Elbakoush,Qudrat Ullah Khan,Mati Ullah,Arif Ullah,Afaq Ullah Khan,Javed Khan,Asra Iftikhar 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

The carbonization performance of the iron-containing carbon film resulting from polyimide was examined, Polyimide/Fe composite films were prepared from Iron (III) 2,4-pentanedionate (Fe(acac)) and poly(amic acid) (PAA) based on ODA and PMDA via a solution process in DMAC, followed by carbonization the polyimide film at a temperature range of 600–1600 °C. The organized polyimide/Fe combined fi lms were characterized using a scanning electron microscope (SEM), and thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Raman. The formation of Fe particles and the synthesis of polyimide (PMDA/ODA) in the polyimide matrix is confirmed by FTIR results. Meantime, in the polyimide matrix, Fe particles were well spread which were showed by the SEM images. Kinetic parameters and thermal stability of the degradation methods for the organized polyimide/Fe combined films were examined in N 2 environment by TGA. The results have shown that the values of the calculated activation energies and thermal stability increased of the (Fe (acac)) the activation energy and loading also different with the weight-loss rate for all compositions.

Robustness and Performance Parameterization of Smooth Second Order Sliding Mode Control

Imran Khan,Aamer Iqbal Bhatti,Ali Arshad,Qudrat Khan 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.3

Novel robustness and performance parameters are established for Smooth Super Twisting Algorithm(SSTA). The stability of SSTA is well established for arbitrary gains using homogeneity approach. The designand tuning of the controller parameters is a major issue and no analytic design method is available so far. Anovel Lyapunov function is proposed and by the virtue of stability analysis, the stability bounds for a certain classof uncertainties are determined. In addition, the issue of finite time convergence is also explored, resulting indetermination of the settling time as a function of the controller parameters. The proposed settling time formulationsuggests a methodical approach to SSTA design in contrast to the available rules of thumb. Unlike the literatureavailable for Higher Order Sliding Mode (HOSM) controllers, the proposed design framework is validated againsta challenging problem of the Underground Coal Gasification (UCG) process control. Like the other process controlproblems the chosen problem is nonlinear and contains significant uncertainties.