期刊名称：Journal of Emerging Trends in Computing and Information Sciences
电子版ISSN：2079-8407
出版年度：2011
页码：17-21
出版社：ARPN Publishers
摘要：In this paper, wavelet based PID controller is studied. There are two different approaches by which a frequency analysis of a time dependent signal can be affected, locally in time. The first procedure is the short-time FT, the second is the ‘wavelet Transform' in which high frequency component are studied with sharper time resolution than low frequency components. The similarities and differences between these two are studied. The principle of PID control system is simple and function is robust if it were well tuned, however it tends to fall in sustaining oscillations state because of bad tuning in actual plant. The non-linear and time-varying natures of the process together with the large disturbances of several types were the key challenge for the control design. A controller based on multi- resolution decomposition using wavelets is presented in the paper. The controller is similar to proportional integral derivative controller in principle and application. The principle of PID control system is simple and function is robust if it were well tuned, however, it tends to fall in sustaining oscillation state because of bad tuning in actual plant. Also, the output from a control system represents the cumulative effect of uncertainties such as measurement noise, frictional variations and external torque disturbances which manifest at different scales. These scales are then used to compensate for the uncertainties in the plant. The wavelet is used to decompose the error signal into signals at different scales. These signals are then used to compensate for the uncertainties in the plant.
