Showing papers by "Anindita Sengupta published in 2014"

Yarn hairiness evaluation using image processing

Abstract: Yarn hairiness or amounts of released fibers from the staple yarn are one of the main aspects to detect the yarn quality. This paper illustrates the method of finding yarn hairiness using image processing techniques with a low-cost USB Web Camera in association with a yarn moving arrangement. The steps involved with the image processing comprises of segmenting the yarn core from the image and fibre extraction. The yarn hairiness found by the proposed method are quantised by different indices, such as yarn hair area index and yarn hair length index and count of hair tips at specific distances from the central line of the yarn core. The future goal of this work is to acquire the image of the yarn from a spinning frame with the help of a high resolution web camera and process the same with advanced software to characterize the yarn which in turn dictates the fabric appearance in terms of hairiness.

Application of MRPID Controller on Liquid Level System: A Performance study

Abstract: Comparative study of the performance of Wavelet based Multi Resolution PID (MRPID) controller over conventional PID controller for a Liquid level system is presented in this paper. In the proposed wavelet based PID controller, the discrete wavelet transform (DWT) is used to decompose the error signal available from the set point signal and measured signal into different frequency components at various levels. Then the calculated DWT coefficients are multiplied with their respective gains to generate an overall control signal. Both the controllers are simulated in LabVIEW software. After implementation of software model successfully, plant is realized in hardware with controller simulated in PC. The performances of the wavelet- based MRPID controller are found to be superior to that of the conventional PID controller even in the presence of the white noise. resolutions at lower frequency, and coarse frequency resolution and fine time resolution at higher frequency. It makes the wavelet transform suitable for time-frequency analysis. Heil and Walnut (5) used time-frequency localization of wavelet transforms in process control industry. In this paper, a direct application of wavelet transform to controller design is proposed. Eminent researchers (6-10) developed the concept of a new controllers i.e. multi resolution PID controller for the application in process control, speed and position control of different types of motor etc. In this paper, new wavelet based controller has been applied for liquid level system. The wavelet controller decomposes the error between set point level and measured level into different frequency components at various levels. The transform coefficients at different scales represent many underlying phenomena such as process dynamics, measurement noise and effects of external disturbances. Each of these components are scaled by their respective gains, and then added together to generate the control signal u. In the next section II and III, a brief description of hardware implementation of liquid level system and MRPID controller is discussed. Simulation results are shown in section IV.

DWT based repetitive controller for tracking of periodic reference signal

Abstract: The objective of this work is to apply repetitive control strategy in an existing laboratory based Liquid Level System for tracking of periodic trajectories applied in the set point or rejecting periodic disturbances with known period. This paper deals with different conventional control techniques and repetitive control strategy for the Liquid Level System (LLS). The main objective of this paper is to demonstrates in steps the ways of design and implementation of Repetitive Control System (RCS) for the plant and in advance an attempt have been taken to reduce the memory size of the repetitive controller by the application of Discrete Wavelet Transform and Inverse Discrete Wavelet Transform in the repetitive control loop i.e. Discrete Wavelet Repetitive Control System (DWRCS) is experimented. Comparisons in terms of performances in both time & frequency (using bode plot) domain are done to show the effectiveness of the DWRCS over the traditional ideas.

Robust servo performance of repetitive controller for periodic reference signals

Abstract: The objective of this work is to validate the servo mechanism property of Repetitive Control (RC) system for periodic reference input in the presence of disturbance and in the presence of time varying parametric uncertainty. The ways of design & implementation of repetitive control system is demonstrated in steps. A similar test have been made having conventional PI-control and compared with RC based P control. Comparisons in terms of performances in both time & frequency (using bode plot) domain are done to show the effectiveness of the RC over the traditional idea.