Browsing by Author "LIU, TS"

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A COMPONENT BEHAVIORAL-MODEL FOR AUTOMATIC FAULT-TREE CONSTRUCTION
(1993)
WANG, JD
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LIU, TS
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機械工程學系
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Department of Mechanical Engineering
This study presents a new definition of events, an extended decision table, a virtual transfer component, and two pruning procedures for use in systematically constructing fault trees. The component states are modelled by events, which are defined by both qualitative event descriptions and quantitative event types. The quantitative event types are proposed to clarify the vagueness inherent in qualitative event descriptions. Moreover, decision tables, which are employed in the literature to model the behaviour of components, are extended in this study to generate succinct fault trees. A virtual transfer component is defined to deal with redundancy, such as k-out-of-n and standby modules. The construction of fault trees begins with the TOP event and traces backward to the primary and undeveloped events of components based on the structural configuration of the system and extended decision tables stored in a database. Procedures for producing transfer symbols and combining successive logic gates with gates of the same type are proposed to prune the generated fault tree during and after the tracing process, thereby reducing the construction time and the amount of computer memory needed. A hydraulic brake system and a pressure tank system are employed as examples to demonstrate the proposed method. The results of the examples show that the proposed method efficiently generates succinct fault trees for systems with redundancy.
A DISCRETE STRESS STRENGTH INTERFERENCE MODEL FOR UNRELIABILITY BOUNDS
(1994)
WANG, JD
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LIU, TS
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機械工程學系
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Department of Mechanical Engineering
This study presents a multiple-line-segment method of implementing the stress-strength interference model when only discrete interval probabilities of stress and strength inside an interference region are available. Based on the discrete interval probabilities, the probability density functions are represented by line segments, which are in turn expressed by piecewise linear polynomials. Thus, unlike in existing empirical methods, when both stress and strength fall into the same subinterval, one can calculate the probability of failure by directly integrating the joint probability of stress and strength over the subinterval. Quadratic programming optimization is implemented to determine the upper and lower bounds on the failure probability, and the average value of the bounds is treated as the point estimate of the failure probability. Finally, numerical examples are carried out to demonstrate the proposed method. Three quantities are used to evaluate the accuracy and effectiveness of the proposed method-the relative error of the point estimate of the unreliability, the width of the bounds on the unreliability, and the minimum number of subintervals needed to generate the bounds that contain the exact unreliability. These three quantities are compared with results in the literature.
A FUZZY MODEL OF RIDER CONTROL FOR A MOTORCYCLE UNDERGOING LANE CHANGE
(1994)
WU, JC
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LIU, TS
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交大名義發表
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機械工程學系
;
National Chiao Tung University
A rider-motorcycle system can be treated as a representative man-machine system in view of the major role that both the rider and the motorcycle play in determining the performance of the integrated system. Of interest in this work is the handling property which is crucial to safety during riding. In this study, al mathematical model of three-dimensional multi-body dynamics is constructed, which accounts for not only motorcycle dynamics but also the rider's posture change. Since a fuzzy controller is essentially a nonlinear process representing the qualitative knowledge of human experts on the behaviour of systems and desired control actions, a fuzzy control method is applied to determine a rider's handling action. The fuzzy controller based on fuzzy rules and fuzzy reasoning methods plays the role of the rider in a rider-motorcycle system. Accordingly, a rider-motorcycle system undergoing lane change is simulated. The time variation of steering angle, yaw rate, and lateral acceleration are demonstrated. Effects of yaw rate and lateral acceleration on handling property are examined-based on Bode plots.
A MODEL FOR A RIDER MOTORCYCLE SYSTEM USING FUZZY CONTROL
(1993-01-01)
LIU, TS
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WU, JC
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
A rider-motorcycle system is a representative man-machine system in view of the major role that the rider plays in determining the performance of the integrated system. The handling property of motorcycles influences safety during riding. In the study, a motorcycle model subjected to fuzzy control representing rider's perception and action is investigated to facilitate motorcycle design. A mathematical model of three-dimensional (3-D) multibody dynamics is constructed, which accounts for not only motorcycle structures but also the rider's posture change. The fuzzy controller based on control rules and fuzzy reasoning methods plays the role of the rider in a rider-motorcycle system. The fuzzy control is facilitated by the construction of look-up tables. A rider-motorcycle system undergoing circular motion is simulated. The study provides a viable means for computer-aided design of a representative man-machine control system.
A RELIABILITY APPROACH TO EVALUATING ROBOT ACCURACY PERFORMANCE
(1994-01-01)
LIU, TS
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WANG, JD
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
The capability of a robot to position its end-effector with accuracy is an important attribute for advanced robots in industrial automation technology. This study aims to assess positioning accuracy of robot end-effectors using reliability approaches. The reliability provides a statistical means for representing robot accuracy. Both the linear regression and iterative Taylor series methods are used to deal with limit states in reliability calculation. The proposed iterative Taylor series method improves computation accuracy compared with the prior literature. Both computer simulations and experiments were conducted to verify the performance of the accuracy assessment method. Examples show that the positioning accuracy is sensitive to tolerances of arm length and actuating accelerations. More important, dynamic errors, in comparison to geometric and kinematic errors, influence accuracy significantly.
An augmented system model for fault detection and identification
(1995)
LIU, TS
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LIOU, JJ
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機械工程學系
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Department of Mechanical Engineering
AUTOMATIC FAULT-TREE CONSTRUCTION USING A NEW COMPONENT BEHAVIORAL-MODEL
(1994)
LIU, TS
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WANG, JD
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交大名義發表
;
National Chiao Tung University
DYNAMIC ANALYSIS OF FLEXIBLE LINKAGES WITH LUBRICATED JOINTS
(1990-09-08)
LIU, TS
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LIN, YS
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交大名義發表
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機械工程學系
;
National Chiao Tung University
EXTRUSION ANALYSIS AND WORKABILITY PREDICTION USING FINITE-ELEMENT METHOD
(1990)
LIU, TS
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CHUNG, NL
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交大名義發表
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機械工程學系
;
National Chiao Tung University
FATIGUE RELIABILITY OF STRUCTURES BASED ON PROBABILITY AND POSSIBILITY MEASURES
(1992-10-03)
LIU, TS
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HUANG, GR
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
The randomness of fatigue life prediction has been commonly recognized, but recently researchers have begun to recognize the fuzziness of fatigue failure descriptions resulting from the lack of distinct definitions and precise information. In this paper, both probability- and possibility-based reliabilities of components subjected to fatigue loading are investigated. In the probability-based reliability, the material properties and the amplitude of a loading history are assumed to be random. In the possibility-based method, the fuzzy linear regression method is employed to account for the fuzziness. This work employs S-functions to define fuzzy limit state functions. Failure probabilities are calculated in terms of probability distributions of fuzzy damage and fuzzy limit state functions. Both probability- and possibility-based reliabilities of a portal frame are examined. Accordingly, the reliability of systems in the presence of fuzziness is calculated and compared to the results obtained from the probability-based method.
FORCED VIBRATION OF FLEXIBLE BODY SYSTEMS - A DYNAMIC STIFFNESS METHOD
(1993-10-01)
LIU, TS
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LIN, JC
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
Due to the development of high speed machinery, robots, and aerospace structures, the research of flexible body systems undergoing both gross motion and elastic deformation has seen increasing importance. The finite element method and modal analysis are often used in formulating equations of motion for dynamic analysis of the systems which entail time domain, forced vibration analysis. This study develops a new method based on dynamic stiffness to investigate forced vibration of flexible body systems. In contrast to the conventional finite element method, shape functions and stiffness matrices used in this study are derived from equations of motion for continuum beams. Hence, the resulting shape functions are named as dynamic shape functions. By applying the dynamic shape functions, the mass and stiffness matrices of a beam element are derived. The virtual work principle is employed to formulate equations of motion. Not only the coupling of gross motion and elastic deformation, but also the stiffening effect of axial forces is taken into account. Simulation results of a cantilever beam, a rotating beam, and a slider crank mechanism are compared with the literature to verify the proposed method.
FUZZY CONTROL OF RIDER-MOTORCYCLE SYSTEM USING GENETIC ALGORITHM AND AUTOTUNING
(1995-06-01)
WU, JC
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LIU, TS
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機械工程學系
;
Department of Mechanical Engineering
This study investigates the stability control of a rider-motorcycle system based on fuzzy control in conjunction with both genetic algorithm (GA) and an auto-tuning method. The autotuning method, which entails tuning rules, is employed to on-line adjust output gains of fuzzy control. Although a GA has been used for fuzzy control in the literature, it has been confined to aiding membership functions' enaction. By contrast, this study employs a GA to determine optimal parameters in control rules for fuzzy control and in tuning rules for the auto-tuning method. Both computer simulation and experiment with regard to an inverted pendulum hinged to a rotating disk are carried out to represent the circular motion of the rider-motorcycle system, in which the inverted pendulum represents a rider's body in banking motion. The relation between riding speeds of the motorcycle and leaning angles of the rider is examined based on speed variations and Bode plots. Simulation and experimental results show the significant effect of the rider's banking angle on stability control.
NONLINEAR-ANALYSIS OF STABILITY FOR MOTORCYCLE-RIDER SYSTEMS
(1992)
LIU, TS
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CHEN, JS
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交大名義發表
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機械工程學系
;
National Chiao Tung University
In this study, linear and nonlinear analyses of motorcycle-rider motion are carried out to investigate the stability of the motorcycle-rider integrated system. Equations of motion are derived using Lagrange's equation. Transfer functions that account for the rider's perception and action are taken into account. In the linear analysis, its dynamic behaviour is characterized by eigenvalues and eigenvectors. The effects of design parameter changes on capsize. weave and wobble modes are examined, and the design implication is discussed. The nonlinear analysis for system stability is conducted by means of the centre manifold theory and bifurcation theory. Stability boundaries in a parameter space and the corresponding bifurcation diagrams are obtained for in-depth understanding of the system stability. Moreover, comparison of results with and without rider's control shows the significant effect of the rider on the stability performance of the entire system.
SINGULARITY OF ROBOTIC KINEMATICS - A DIFFERENTIAL MOTION APPROACH
(1990)
LIU, TS
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TSAY, SY
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交大名義發表
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機械工程學系
;
National Chiao Tung University
THE TAGUCHI METHOD APPLIED TO MOTORCYCLE HANDLING
(1991)
LIU, TS
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HSIAO, IH
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交大名義發表
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機械工程學系
;
National Chiao Tung University
This study aims to determine quantitatively how various suspensions, trials, riders, riding speeds, and directions affect motorcycle handling. In the development of vehicle handling tests, steady state turns are carried out. A video-based image analysis technique is applied to acquire data and a statistics-based Taguchi method is used to analyse it. Variance analyses are carried out to assess the factors which contribute to the performance of motorcycle handling. It is shown that trail lengths are critical design parameters. Also, rider techniques dominate 55% of handling performance in a rider-motorcycle system. Among several different trails and rear suspensions, the best design is determined by statistical calculation using the Taguchi method.
TYPE SYNTHESIS OF VEHICLE PLANAR SUSPENSION MECHANISM USING GRAPH-THEORY
(1993-09-01)
LIU, TS
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CHOU, CC
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交大名義發表
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機械工程學系
;
National Chiao Tung University
This paper presents a graph theory-based approach to optimum type synthesis of vehicle suspension mechanisms using an expert system. Kinematic chain isomorphism is identified, using an extended degree method to facilitate the enumeration of kinematic structures. Rules representing design criteria and the flow value theory based on energy loss calculation are incorporated in the rule base to evaluate and select mechanisms among those that are enumerated in the database. Statistical variance calculation serves to complement the flow value theory. A new method called the extended flow value method is devised for isomorphism checking of labeled graphs. In the spirit of increasing emphasis on the riding quality of vehicles, several novel suspension configurations are created to ensure maintenance ease and vibration damping efficiency.