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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Direct Adaptive Input Shaping Using On-Line Frequency Domain Information and Extremum-Seeking Optimization) ผู้เขียน: ดร.วิทิต ฉัตรรัตนกุลชัย, รองศาสตราจารย์ ,  Sermsak Chotana, ชลวิทย์ พฤทธพงศ์ สื่อสิ่งพิมพ์:pdf AbstractThe input shaping technique convolves the reference command with a properly designed impulse sequence, creating a shaped reference command that avoids exciting the under-damped vibratory system to achieve zero residual vibration on a point-to-point maneuver. The input shaper needs to know the natural frequencies and damping ratios of the vibratory system to design such an impulse sequence. When system configurations change, the natural frequencies and damping ratios also change, and the input shaper must be updated with this new information. In this paper, a point-by-point discrete Fourier transform (DFT) algorithm was used to compute the frequency content of the vibratory signal. The identified natural frequencies were directly updated into the input shaper. Extremum-seeking optimization was used to further adjust the damping ratios for minimal vibration. The proposed technique was applied to a flexible-link robot manipulator. The manipulator was commanded to have a point-to-point maneuver with changing payload. The experimental results, based on cases with or without DFT and extremum seeking, showed that with the proposed technique, minimum residual vibration was obtained even when the payload changed, without having to know the amount of payload. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Extremum-Seeking Gain-Scheduled Adaptive Input Shaping Applied to Flexible-Link Robot) ผู้เขียน:ดร.วิทิต ฉัตรรัตนกุลชัย, รองศาสตราจารย์, Sermsak Chotana, ชลวิทย์ พฤทธพงศ์ สื่อสิ่งพิมพ์:pdf AbstractInput shaping was used to design a finite impulse response (FIR) prefilter. This filter, when convoluted with a reference input, produces a shaped reference input that avoids resonance, resulting in significantly less residual vibration. A flexible system that follows this shaped reference input is able to move from point to point faster due to less settling time. The problem with traditional input shaping is that the filter requires knowledge of the system’s natural frequencies and damping ratios and hence its performance deteriorates when the system is time varying. This paper proposed a novel adaptive input shaping algorithm. The system’s natural frequencies and damping ratios were gain-scheduled based on system-measured states and were simultaneously adjusted by extremum seeking for minimum residual vibration. The proposed algorithm was applied to the point-to-point movement of a one-link, flexible-link robot manipulator whose payload varied with time. The experimental results confirmed the effectiveness of the proposed algorithm, compared with the unadaptive case. |
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