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Composite PD and Fuzzy Logic Approach for Vibration of Elastic Joint Manipulator
Mohd Ashraf Ahmad,Raja Mohd Taufika Raja Ismail,Mohd Syakirin Ramli,Mohd Anwar Zawawi,Mohd Helmi Suid 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
The increased complexity of the dynamics of robots manipulator considering joint elasticity makes conventional model-based control strategies complex and difficult to synthesize. This paper presents investigations into the development of composite collocated proportional-derivative (PD) and Fuzzy Logic Control for trajectory tracking and vibration control of a flexible joint manipulator respectively. To study the effectiveness of the controllers, a collocated PD Controller is developed for tip angular position control of a flexible joint manipulator. This is then extended to incorporate a non-collocated Fuzzy Logic Controller for vibration reduction of the flexible joint system. Simulation results of the response of the flexible joint manipulator with the controllers are presented in time and frequency domains. The performances of the composite control schemes are examined in terms of input tracking capability, level of vibration reduction and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.
Mohd Ashraf Ahmad,Shun-ichi Azuma,Toshiharu Sugie 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10
This paper performs an initial study on identification of continuous-time Hammerstein models based on Simultaneous Perturbation Stochastic Approximation (SPSA). While the structure information such as the system order is available for the linear subsystems, the structure of nonlinear subsystem is assumed to be completely unknown. For handling it, a piecewise-linear functions are used as a tool to approximate the unknown nonlinear functions. The SPSA based method is then used to estimate the parameters in both the linear and nonlinear parts based on the given input and output data. A numerical example is given to illustrate that the SPSA based algorithm can give an accurate parameter estimation of the Hammerstein models with high probability through detailed simulation.
Sine based Bacterial Foraging Algorithm for a Dynamic Modelling of a Twin Rotor System
Shuhairie Mohammad,Mohd Falfazli Mat Jusof,Nurul Amira Mhd Rizal,Ahmad Azwan Abd Razak,Ahmad Nor Kasruddin Nasir,Raja Mohd Taufika Raja Ismail,Mohd Ashraf Ahmad 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
This paper introduces a sine-based position update strategy into Bacterial Foraging Algorithm (BFA). In solving many optimization problems, BFA produces an acceptable accurate solution but it presents a slow convergence speed towards the global solution. On the other hand, a sine-based position update strategy from the Sine Cosine Algorithm (SCA) utilizes an elitism in its position update equation. The elitism strategy contains a promising solution that guiding search agents toward global optima with relatively a faster speed. In this proposed technique, the sine-based position update strategy is incorporated prior to the reproduction phase of the BFA. With the consideration of the advantages of the elitism, it helps the BFA to converge faster and hence acquires better accuracy of the final solution. The proposed algorithm is tested on several CEC2014 benchmark functions that have various fitness landscapes and features. For solving a real world problem, it is applied to optimize a dynamic model of a Twin Rotor System. Result of the test shows that the proposed algorithm significantly outperforms the original BFA for both convergence speed and accuracy performances. On the other hand, result of the modelling shows that the proposed algorithm acquires the dynamic model for the Twin Rotor System with a significant smaller error.
Hybrid Sine-Spiral Dynamic Algorithm for Dynamic Modelling of a Flexible Manipulator
Nurul Amira Mhd Rizal,Shuhairie Mohammad,Ahmad Azwan Abd Razak,Mohd Falfazli Mat Jusof,Ahmad Nor Kasruddin Nasir,Mohd Ashraf Ahmad,Addie Irawan Hashim 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
This paper presents a newly developed algorithm formulated based on a synergy between a mathematical sine equation and a spiral equation. The sine formula is taken from Sine-Cosine Algorithm (SCA) while the spiral equation is adopted from Spiral Dynamic Algorithm (SDA). The synergy combines a deterministic approach from SDA and a random approach from SCA. In the hybrid strategy, all agents update their position either via sine based or spiral based position update equation. The proposed hybrid algorithm is tested in comparison to SDA and SCA on various benchmark functions. A convergence plot and accuracy achievement are recorded and compared. In term of a real world application, the algorithm is applied to optimize a parametric model of an end point acceleration of a flexible manipulator robot. Result of the benchmark functions test shows that the proposed algorithm significantly improves the accuracy of both SCA and SDA. Result of the modelling shows that the SCA, SDA and the proposed algorithm have successfully modelled the end point acceleration.
Irfan Ahmad Bhat,Rupam Sharma,Mohd Ashraf Rather,Pravesh Kumar Rathor,P. Gireesh‑Babu,Mukunda Goswami,J. K. Sundaray 한국유전학회 2017 Genes & Genomics Vol.39 No.9
The steroidogenic acute regulatory protein (StAR) plays a key role in transferring cholesterol across the inner mitochondrial membrane. In this study, the StAR gene was isolated from the gonads of Clarias batrachus. The gene has an open reading frame of 857 bp and encodes 285 amino acids with a predicted molecular weight of 32 kDa. The signalP analysis predicted that StAR would be a non-secreted protein that lacks a signal peptide. The subcellular localization demonstrated that the presence of the StAR protein was higher in mitochondria (41.8%), followed by the nuclear region (37.1%) and cytoplasm (11.1%). The StAR protein was found to interact highly with cyp11a1, followed by the cytochrome P450 family 11 proteins and the START5 domain. The homology modelling revealed that the protein has 4 helices and twisted U-shaped 10 beta sheets numbered from αA to αD and β1 to β10, respectively. Molecular modelling analysis showed that resveratrol and eurycomanone has high binding affinity with the StAR protein. The C. batrachus StAR transcript was found to be expressed exclusively in the gonads, kidney, and liver. These results overall lay a solid foundation for understanding the structure of StAR protein in fish. The identification of 3D structures and binding sites will help in designing a structure-based drug of StAR agonists for the treatment of impaired steroidogenesis.
Suid, Mohd Helmi,Jusof, M F.M.,Ahmad, Mohd Ashraf The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3
A new nonlinear filtering algorithm for effectively denoising images corrupted by the random-valued impulse noise, called dual sliding statistics switching median (DSSSM) filter is presented in this paper. The proposed DSSSM filter is made up of two subunits; i.e. Impulse noise detection and noise filtering. Initially, the impulse noise detection stage of DSSSM algorithm begins by processing the statistics of a localized detection window in sorted order and non-sorted order, simultaneously. Next, the median of absolute difference (MAD) obtained from both sorted statistics and non-sorted statistics will be further processed in order to classify any possible noise pixels. Subsequently, the filtering stage will replace the detected noise pixels with the estimated median value of the surrounding pixels. In addition, fuzzy based local information is used in the filtering stage to help the filter preserves the edges and details. Extensive simulations results conducted on gray scale images indicate that the DSSSM filter performs significantly better than a number of well-known impulse noise filters existing in literature in terms of noise suppression and detail preservation; with as much as 30% impulse noise corruption rate. Finally, this DSSSM filter is algorithmically simple and suitable to be implemented for electronic imaging products.