Browsing by Author "Liao, CS"

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A novel master switching method for electronic cam control with special reference to multi-axis coordinated trajectory following
(2006-02-01)
Chang, YH
;
Chieng, WH
;
Liao, CS
;
Jeng, SL
;
機械工程學系
Multi-axis coordinated trajectory following is important in CNC machines and metal cutting tools. Recently, flight simulators with electrical actuators have been in increasing demand. However, the coordinate control scheme affects the accuracy of the motion because motors have an insufficient load-capacity relative to the hydraulic actuators. The electronic cam (ECAM) is typically used to perform coordinated control. However, selection of the master may determine potentially very different characteristics of motion. This study proposes an automatic master switching method. The conditions and results of the master switching method for ECAM are detailed. The robustness and stability of the proposed control system is also demonstrated using the well-known structured perturbation analysis tool, mu. (c) 2005 Elsevier Ltd. All rights reserved.
A novel washout filter design for a six degree-of-freedom motion simulator
(2004-06-01)
Liao, CS
;
Huang, CF
;
Chieng, WH
;
機械工程學系
;
Department of Mechanical Engineering
The motion cue performed by a motion simulator is restrained by the workspace of the simulator structure. A typical reasoning is then to build a large motion simulator. unless it is for entertainment, which involves in small simulators. This study proposes a novel approach to designing the washout filter of the motion control of a six degree-of-freedom motion simulator for entertainment purposes. Using information obtained from the inverse kinematics of the simulator, the workspace boundary, detected in real-time, is fed into the washout filter as a reference for the motion planning. The main focus of this approach is to make the motion cue feasible for use in a simulator with a restricted workspace, while ensuring the robustness of the driving system. In this paper, different indices are established to specify the performance of the motion cue. A classical linear washout filter was implemented and compared with the proposed washout filter using the performance indices to demonstrate the benefits of the latter.
Algorithmic aspect of k-tuple domination in graphs
(2002-09-01)
Liao, CS
;
Chang, GJ
;
應用數學系
;
Department of Applied Mathematics
In a graph G, a vertex is said to dominate itself and all of its neighbors. For a fixed positive integer k, the k-tuple domination problem is to find a minimum sized vertex subset such that every vertex in the graph is dominated by at least k vertices in this set. The present paper studies the k-tuple domination problem in graphs from an algorithmic point of view. In particular, we give a linear-time algorithm for the 2-tuple domination problem in trees by employing a labeling method.
Electronic cam motion generation with special reference to constrained velocity, acceleration, and jerk
(2004-07-01)
Liao, CS
;
Jeng, SL
;
Chieng, WH
;
機械工程學系
;
Department of Mechanical Engineering
Electronic cam motion involves velocity tracking control of the master motor and trajectory generation of the slave motor. Special concerns such as the limits of the velocity, acceleration, and jerk are beyond the considerations in the conventional electronic cam motion control. This study proposes the curve-fitting of a Lagrange polynomial to the cam profile, based on trajectory optimization by cubic B-spline interpolation. The proposed algorithms may yield a higher tracking precision than the conventional master-slaves control method does, providing an optimization problem is concerned. The optimization problem contains three dynamic constraints including velocity, acceleration, and jerk of the motor system. (C) 2004 ISA-The Instrumentation, Systems, and Automation Society.
Sequence distribution and polydispersity index affect the hydrogen-bonding strength of poly(vinylphenol-co-methyl methacrylate) copolymers
(2005-07-26)
Lin, CL
;
Chen, WC
;
Liao, CS
;
Su, YC
;
Huang, CF
A series of poly(vinylphenol-co-methyl methacrylate) (PVPh-co-PMMA) block and random copolymers were prepared through anionic and free radical polymerizations, respectively, of 4-tert-butoxystyrene and methyl methacrylate and subsequent selective hydrolysis of the 4-tert-butoxystyrene protective groups. Analysis of infrared spectra suggests that the random copolymer possesses a higher fraction of hydrogen-bonded carbonyl groups and a larger interassociation equilibrium constant relative to those of a block copolymer containing similar vinylphenol content because of the different sequence distribution that may arise from the so-called intramolecular screening effect. In contrast, the glass transition temperature of the block copolymer, which has the lower polydispersity index, is higher than that of the random copolymer at the same composition.