Department of Mechanical engineering
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Item Reliability Based Approach to Manipulator Parameter Design(BITS-Pilani, 2006) Rout, Bijay KumarThe work illustrates simulation approach for parametric design and optimizing the performance of a 2-DOF RR planar manipulator. Using dynamic and kinematic models of a manipulator different performance measures for the manipulator are obtained for different combination of parameters with effect of noise incorporated to imitate the real time performance of the manipulator. A novel approach has been used to model, the otherwise difficult to model, noise effects. The data generated during simulation for various parameter combinations are utilized to analyze the statistical significance of kinematic and dynamic parameters on performance of manipulator using ANOVA technique. Optimal parameter combinations, which gave optimum performance measures, for a point in workspace are obtained and compared.Item NDENet: End-to-End Nighttime Dehazing and Enhancement(World Academy of Science, Engineering and Technology, 2007-01) Rout, Bijay KumarIn this paper, we present a computer vision task called nighttime dehaze-enhancement. This task aims to jointly perform dehazing and lightness enhancement. Our task fundamentally differs from nighttime dehazing – our goal is to jointly dehaze and enhance scenes, while nighttime dehazing aims to dehaze scenes under a nighttime setting. In order to facilitate further research on this task, we release a benchmark dataset called Reside-β Night dataset, consisting of 4122 nighttime hazed images from 2061 scenes and 2061 ground truth images. Moreover, we also propose a network called NDENet (Nighttime Dehaze-Enhancement Network), which jointly performs dehazing and low-light enhancement in an end-to-end manner. We evaluate our method on the proposed benchmark and achieve Structural Index Similarity (SSIM) of 0.8962 and Peak Signal to Noise Ratio (PSNR) of 26.25. We also compare our network with other baseline networks on our benchmark to demonstrate the effectiveness of our approach. We believe that nighttime dehaze-enhancement is an essential task particularly for autonomous navigation applications, and hope that our work will open up new frontiers in research. The code for our network is made publicly available.Item Optimal manipulator tolerance design using hybrid evolutionary optimization technique(ACM Digital Library, 2007-09) Rout, Bijay KumarThere is a need to select optimal parameter tolerance of manipulator to reach an economic balance between the desired performance and its manufacturing cost. However, selection of optimal parameter tolerances of manipulator is a challenging task. Present paper discusses an offline approach to incorporate effect of noise in simulation of performance and handle its effect in optimization process of parameters tolerances. To determine optimal parameter tolerances, a hybrid evolutionary optimization technique has been used. The hybrid is formed between differential evolution optimization technique and orthogonal array used in design of experiments technique. Proposed technique has been illustrated by selecting optimal tolerances of 2-DOF RR planar manipulator. It has been observed that the methodology is a viable alternative to the costly prototype testing, where only mathematical models are dealt with.Item Simultaneous selection of optimal parameters and tolerance of manipulator using evolutionary optimization technique(Springer, 2009-04) Rout, Bijay KumarFor precise industrial applications, a manipulator must have high positioning accuracy and repeatability. However, variations in performance of the manipulator are attributed to improper selection of dimensions of design and process parameters and its tolerance. There have been almost no attempts to optimize these parameters and tolerance of the manipulator, by which performance variations will be minimum. This paper presents an offline approach to select optimal parameters and tolerance simultaneously which minimizes the manufacturing cost and delivers the target performance level. To determine the optimal parameters and tolerances, a modification in differential evolution algorithm is proposed, which helps in incorporating the effect of uncertainty in optimization process. Proposed approach has been illustrated by selecting optimal parameters and tolerance of a 2-DOF RR planar manipulator. The performance of this approach has been compared with modified genetic algorithm. It is observed that differential evolution algorithm provides optimal results with lesser computations compared to genetic algorithm.Item Tolerance design of manipulator parameters using design of experiment approach(Springer, 2007-03) Rout, Bijay KumarA robotic arm must manipulate objects with high accuracy and repeatability to perform precise tasks. There are many factors that cause variations in performance and they referred as noise factors. A probabilistic approach has been used to model the effects of noise factors and an experimental design technique has been adopted to select optimal tolerance of kinematic and dynamic parameters for minimal performance variations. The control and noise factor arrays are employed to identify statistically significant parameters and their interactions. The performance measures like signal to noise ratio and reliability have been utilized and results are validated by Monte Carlo simulations. The proposed design of experiment methodology requires minimal computations. The tolerance design methodology of manipulator is illustrated by 2-DOF revolute–revolute planar manipulator following cubic and quintic trajectory to perform a task. The statistical analysis of simulated performances is carried out using analysis of variance technique, which showed that statistically significant parameters are independent of trajectory. The individual parameter tolerance sensitivity has also been carried out.Item Screening of factors influencing the performance of manipulator using combined array design of experiment approach(Elsevier, 2009-06) Rout, Bijay KumarA robot must manipulate objects with high accuracy and repeatability to perform precise tasks. However, deviation in performance is attributed to uncertainties and improper selection of control, noise, and process factors. The information regarding the effect of these factors on performance is almost non-existent. A probabilistic approach has been used to model and simulate the performance of manipulator. The combined array fractional factorial design of experiment approach has been employed to identify the significant factors and their interactions. This approach helps in screening of the manipulator factors and focus on those that are important. To explore further, two indices, viz. link length ratio and link mass ratio, have been proposed and impact of these indices on manipulator performance is investigated. A two degree of freedom (2-DOF) RR planar manipulator performing a task with cubic and quintic trajectory has been used to illustrate the approach. It has been observed that the statistically significant factors are different for different tasks in workspace. It has also been observed that for the same task, factors responsible for performance variations are different for cubic and quintic trajectories. Finally, it has been demonstrated that the link length ratio change has significant influence on performance compared to link mass ratio.Item Optimal manipulator parameter tolerance selection using evolutionary optimization technique(Elsevier, 2008-06) Rout, Bijay KumarRobot system designers often face the challenge of selecting optimal parameter tolerances of a manipulator, which delivers optimal performance. This paper presents an approach to simulate the performance of manipulator and evolutionary optimization method to select optimal parameter tolerance. To determine optimal parameter tolerance, genetic algorithm, and differential evolution, optimization techniques have been used. The objective function maximizes SN Ratio, while manipulator performs a task. As differential evolution and GA are best suited for solving deterministic optimization problems, to handle performance of manipulator, a hybrid technique is proposed. The evolutionary optimization techniques are coupled with orthogonal array used in the Taguchi method to get optimal solution. The hybrid technique is illustrated by an example and concluded that it is best suited for manipulator parameter tolerance design. It is also observed that differential evolution technique converges quickly and require significantly less number of functional evaluations.Item Optimal design of manipulator parameter using evolutionary optimization techniques(CUP, 2009-07) Rout, Bijay KumarA robot must have high positioning accuracy and repeatability for precise applications. However, variations in performance are observed due to the effect of uncertainty in design and process parameters. So far, there has been no attempt to optimize the design parameters of manipulator by which performance variations will be minimum. A modification in differential evolution optimization technique is proposed to incorporate the effect of noises in the optimization process and obtain the optimal design of manipulator, which is insensitive to noises. This approach has been illustrated by selecting optimal parameter of 2-DOF RR planar manipulator and 4-DOF SCARA manipulator. The performance of proposed approach has been compared with genetic algorithm with similar modifications. It is observed that the optimal results are obtained with lesser computations in case of differential evolution technique. This approach is a viable alternative for costly prototype testing, where only kinematic and dynamic models of manipulator are dealt with.Item Tolerance design of robot parameters using Taguchi method(Elsevier, 2006-11) Rout, Bijay KumarA robotic arm must be able to manipulate objects with high accuracy and repeatability. As with every physical system, there are number of noise factors cause uncertainty in the performance. A probabilistic approach has been used to model, the otherwise difficult to model, noise effects. This paper presents the approach utilised in selection of tolerance specification of robot kinematic and dynamic parameters using experimental design technique for reduction of performance variations. The concept of inner and outer orthogonal arrays proposed by Taguchi is employed to identify the significant parameters and select the optimal tolerance range. The performance measure, i.e. signal-to-noise ratio is utilised to validate by Monte Carlo simulations and to complement above study individual parameter tolerance sensitivity are investigated. To provide insight to investigation, parameter sensitivity maps are plotted. The tolerance specification selection methodology of a manipulator is illustrated by taking 2-DOF RR planar manipulator with payloadItem Parametric design optimization of 2-DOF R–R planar manipulator—A design of experiment approach(Elsevier, 2008-04) Rout, Bijay KumarThis work illustrates simulation approach for optimizing the parametric design and performance of a 2-DOF R–R planar manipulator. Using dynamic and kinematic models of a manipulator different performance measures for the manipulator are obtained for different combination of parameters with effect of noise incorporated to imitate the real time performance of the manipulator. A novel approach has been proposed to model, the otherwise difficult to model, noise effects. The data generated during simulation for various parameter combinations are utilized to analyze the statistical significance of kinematic and dynamic parameters on performance of manipulator using ANOVA technique. The parameter combinations, which give optimum performance measures obtained for different points in workspace, are compared and reported.