This paper proposes an arbitrary higher order sliding mode controller for uncertain minimum phase nonlinear systems. The stability proof of the suggested scheme is analyzed in terms of two Lyapunov functions. Using th...
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This paper proposes an arbitrary higher order sliding mode controller for uncertain minimum phase nonlinear systems. The stability proof of the suggested scheme is analyzed in terms of two Lyapunov functions. Using these two Lyapunov functions it is proved that, output and its higher order derivatives converge to origin in finite time. Simulation results prove the efficiency of the proposed method.
A new approach is presented to analyze sliding mode control in discrete-time systems using an established reaching law, whereby the ultimate band is obtained to be lesser than any previous analysis done with the same ...
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A new approach is presented to analyze sliding mode control in discrete-time systems using an established reaching law, whereby the ultimate band is obtained to be lesser than any previous analysis done with the same reaching law. Also, the controller parameters are evaluated according to the ultimate band that is desired. The approach begins with defining several bands in the space of the surface variable, which are key to understanding the dynamics of it. Conditions on these band values are key to assigning appropriate values to the controller parameters. The switching gain obtained in this way comes out to be negative contradicting popular notion of non-negative switching gains used in sliding mode control. A case is also studied where the states measured contribute a quantization error in the system dynamics. The idea developed in analyzing the case without quantization is used while dealing with it.
To investigate the genetic basis of type 2 diabetes (T2D) to high resolution, the GoT2D and T2D-GENES consortia catalogued variation from whole-genome sequencing of 2,657 European individuals and exome sequencing of 1...
To investigate the genetic basis of type 2 diabetes (T2D) to high resolution, the GoT2D and T2D-GENES consortia catalogued variation from whole-genome sequencing of 2,657 European individuals and exome sequencing of 12,940 individuals of multiple ancestries. Over 27M SNPs, indels, and structural variants were identified, including 99% of low-frequency (minor allele frequency [MAF] 0.1-5%) non-coding variants in the whole-genome sequenced individuals and 99.7% of low-frequency coding variants in the whole-exome sequenced individuals. Each variant was tested for association with T2D in the sequenced individuals, and, to increase power, most were tested in larger numbers of individuals (>80% of low-frequency coding variants in ~82 K Europeans via the exome chip, and ~90% of low-frequency non-coding variants in ~44 K Europeans via genotype imputation). The variants, genotypes, and association statistics from these analyses provide the largest reference to date of human genetic information relevant to T2D, for use in activities such as T2D-focused genotype imputation, functional characterization of variants or genes, and other novel analyses to detect associations between sequence variation and T2D.
controller Area Network (CAN) is the dominant network in automotive applications and is making inroads in the industrial and medical environments too. The basic CAN protocol suffers an inherent shortfall that it starv...
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controller Area Network (CAN) is the dominant network in automotive applications and is making inroads in the industrial and medical environments too. The basic CAN protocol suffers an inherent shortfall that it starves low priority nodes to transmit data due to its fixed priority (FP) scheme. The paper proposes implementation of two priority schemes to mitigate the same. In the first scheme, that implements Round-Robin(RR) priority, the access to the bus is given in cyclic fashion. Thus, giving opportunity for lower priority nodes to transmit. In the second scheme, that implements Least Recently Used (LRU) priority, priorities of the nodes are rotated depending on node's recent access of the bus, thereby giving equal opportunity to all the nodes for accessing the bus. Proposed schemes therefore give provisions to change fixed priority scheme of CAN protocol into Round-Robin and Least Recently Used (LRU) priority schemes respectively. Also, the proposed RR and LRU priority schemes can coexist with FP scheme. The proposed schemes are applied at every node which avoids the use of any explicit master node or message scheduler to provide equal opportunity to all the nodes. The proposed schemes do not require changes at physical and data-link layers of CAN protocol. Consideration of emergency state for a particular node is another small contribution of this paper. The proposed emergency priority scheme allows particular nodes to have provision of emergency states for gaining access to the bus out of turn. A software simulation of proposed schemes in LabVIEW verify equitable access to nodes.
One commonly employed actuation device to change the orientation and angular velocity of a satellite is the reaction wheel (or internal rotor.) With this mode of actuation, to achieve any arbitrary orientation and ang...
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One commonly employed actuation device to change the orientation and angular velocity of a satellite is the reaction wheel (or internal rotor.) With this mode of actuation, to achieve any arbitrary orientation and angular velocity, three internal rotors suffice. A problem of long standing interest however, is the aspect of controllability when there are only two rotors - either by design or due to the failure of one rotor. An early result on this problem is by Crouch [1]. The paper affirms that the system is not accessible when there are two rotors. However, there is no attempt to characterize the reachable set in this case. In this paper, using a geometric framework based on the Lagrange -Routh reduction procedure, we characterize the reachable set for the case of two rotors.
A squirrel cage induction generator (SCIG) offers many advantages for wind energy conversion systems but suffers from poor voltage regulation under varying operating conditions. The value of excitation capacitance ...
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A squirrel cage induction generator (SCIG) offers many advantages for wind energy conversion systems but suffers from poor voltage regulation under varying operating conditions. The value of excitation capacitance (C exct ) is very crucial for the selfexcitation and voltage build-up as well as voltage regulation in SCIG. Precise calculation of the value of C exct is, therefore, of considerable practical importance. Most of the existing calculation methods make use of the steady-state model of the SCIG in conjunction with some numerical iterative method to determine the minimum value of C exct . But this results in over estimation, leading to poor transient dynamics. This paper presents a novel method, which can precisely calculate the value of C exct by taking into account the behavior of the magnetizing inductance during saturation. Interval analysis has been used to solve the equations. In the proposed method, a range of magnetizing inductance values in the saturation region are included in the calculation of C exct , required for the self-excitation of a 3-φ induction generator. Mathematical analysis to derive the basic equation and application of interval method is presented. The method also yields the magnetizing inductance value in the saturation region which corresponds to an optimum C exct(min) value. The proposed method is experimentally tested for a 1.1 kW induction generator and has shown improved results.
A new discrete time super-twisting-like second order sliding mode algorithm (DSTA) is proposed. The stability proof of the suggested scheme is analyzed in terms of the discrete Lyapunov approach and Linear Matrix Ineq...
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Whenever we compute control using digital computer, the states measured need to be converted to digital word before processing in the computer. This conversion gives rise to quantization error in state measurement whi...
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Whenever we compute control using digital computer, the states measured need to be converted to digital word before processing in the computer. This conversion gives rise to quantization error in state measurement which in turn affects the applied control to the plant. This would cause the system dynamics to deviate from the behaviour predicted by any theoretical analysis which does not consider the effect of such quantization. Here an analysis has been presented taking into consideration the error due to quantization for Quasi Sliding Mode control with state feedback.
In many mobile robotic tasks, it is important to know the local axis of the robot at any pose with respect to a reference or global direction. In this paper, a vision-based algorithm is described for this purpose. A n...
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In many mobile robotic tasks, it is important to know the local axis of the robot at any pose with respect to a reference or global direction. In this paper, a vision-based algorithm is described for this purpose. A new approach to form the omnidirectional view of an environment is developed using a single camera. The images captured at a definite interval of angles are stitched by a simple method of removing the overlapping area between two successive images. To find the local axis of a mobile robot, a robust technique is developed to determine the orientation of the robot at any pose with respect to the reference direction in an unknown environment. A reference omnidirectional image is correlated with that at the current position. The paper formulates two algorithms : one for finding the fixed amount of overlapping area and another for finding the angle of local axis with respect to the reference using correlation. The paper also proposes two ways using which this visual compass can be used.
A new discrete time super-twisting-like second order sliding mode algorithm (DSTA) is proposed. The stability proof of the suggested scheme is analyzed in terms of the discrete Lyapunov approach and Linear Matrix Ineq...
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A new discrete time super-twisting-like second order sliding mode algorithm (DSTA) is proposed. The stability proof of the suggested scheme is analyzed in terms of the discrete Lyapunov approach and Linear Matrix Inequalities (LMI) theory. Using these two tools it is proved that, system state trajectory is ultimately bounded in finite time. The state estimation problem for a class of second order discrete time system has been proposed to show the positive settings obtained from the algorithm introduced here. Also, the ultimate boundedness of the estimation error is demonstrated despite the presence of bounded perturbations. Simulation results illustrates the efficacy of this new discrete-time algorithm.
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