Chung-Hsien Kuo

Failure modeling and process monitoring for flexible manufacturing systems using colored timed Petri nets

The performance of a flexible manufacturing system (FMS) depends on the equipment efficiency and process control. In order to increase the equipment efficiency, the failure mode analysis and fault diagnosis can be used to reduce the frequency of unexpected breakdowns of machines. In addition, the statistical process control (SPC) can be used for adjusting the process parameters to eliminate process variations. In this paper, a colored timed Petri net (CTPN) is used to model the process behavior of an FMS. In addition, the CTPN-based SPC, fault diagnosis, and failure model and effect analysis are modeled and analyzed individually. Especially, all of the modular models are integrated and linked based on the CTPN. Due to the unified CTPN modeling, the information of each modular model in the entire system can be exchanged and integrated directly and efficiently. Finally, the entire CTPN FMS models are implemented using G2 real-time expert system. Consequently, the proposed CTPN-based simulator can be acted as a real-time FMS monitor and controller through the G2 standard interface.

Design and implementation of Internet-based in-house healthcare and home automation systems

In this paper, we practice an Internet-based in-house healthcare and home automation system. In this work, the components of data acquisition, voice dialing, video grabbing, status monitoring, and Web service are all designed and implemented. Especially, the client-server architecture is used to integrate the hardware and software components. Therefore, the proposed system can be used in the rapidly aging society. The family and the social service related department or agencies are able to take more notices to the elder person who is living alone via the network. The prototype of this system had been implemented. Finally, a demonstration board that simulates the operations of security alarming, appliance control, and data acquisition are also developed to test the Internet-based in-house healthcare and home automation system.

Resource allocation and performance evaluation of the reconfigurable manufacturing systems

The reconfigurable manufacturing system (RMS) is a new concept, and it can increase the product variety and production quantity as well. The key factor of introducing the RMS depends on the redesigned equipment layout and material flows. In order to construct a high performance production system, the allocation of resources must be analyzed first. The paper proposes an equipment layout assignment algorithm (ELAA) to find the near optimal equipment layouts for reducing the cycle time of core products. Consequently, the paper uses the distributed colored timed Petri net (DCTPN) to model the RMS, and the new configuration can be designed based on the resource allocation results. In addition, the performance of the reconfigured manufacturing system is also evaluated based on the DCTPN simulation results. Finally, a simplified 200 mm fab is discussed to demonstrate the procedures of constructing reconfigurable fab models, allocating resources and evaluating the performance.

Human-Oriented Design of Autonomous Navigation Assisted Robotic Wheelchair for Indoor Environments

Wheelchair is one of the most important mobility aids for the disabled people and elders. In this paper, we propose the human-oriented robotic wheelchair design and implementation based on the considerations of convenient driving in narrow space with non-straight paths, active collision avoidance, autonomous navigation, real-time user joystick command justification, intelligent fusion of user joystick command and autonomous navigation systems, and remote monitoring and control. Therefore, this work emphasizes the human-centered manipulations instead of fully autonomous operations of the wheelchair. The developed software components are desired to further detect and avoid mistakes from wrong manipulations of users. In addition, the controllability and comfortability of the wheelchair can be also improved. Especially, the omni-wheeled mechanical platform significantly increases the driving mobility when the robotic wheelchair moves in narrow spaces of indoor environments. Finally, the mechanical platform, closed-loop motion controller, power drives and intelligent software components are all developed in laboratory. The robotic wheelchair was successfully tested. The experimental results validated the proposed robotic wheelchair, and they were discussed in this paper

Eyeglasses based electrooculography human-wheelchair interface

This paper describes an electrooculography (EOG) based human-wheelchair interface for wheelchair users. A pair of electrodes which measures the eye-gaze direction of users is desired as wheelchair manipulation commands. In addition to EOG based wheelchair manipulations, this paper also introduces ultrasonic arrays for detecting distances to actively avoid collisions. In order to simplify setup procedures of using this system, two electrodes are mounted on two side arms of eyeglasses respectively that are possible to have tight contacts with skins around eyes. Therefore, wheelchair movements are capable of following eye-gaze directions. On the other hand, an analog biopotential signal amplifier and a laptop computer are used to develop the proposed EOG based human-wheelchair interface controller. Finally, experimental results demonstrate the operations of EOG based human-wheelchair interface.

Behavior modeling and control of 300 mm fab intrabays using distributed agent oriented Petri net

In a 300 mm integrated circuit (IC) foundry fab, the intrabay automation is more important than a 200 mm one. In general, the intrabay automation systems include the automated controls of the process tools, overhead hoist transports (OHTs), stockers, and rail shortcuts. These control systems are operated concurrently. They must cooperate seamlessly to increase the system performance and to avoid deadlocks. In the paper, the behaviors of the intrabay automation systems are modeled using the distributed agent oriented Petri net (DAOPN). The fab intrabay DAOPN models are categorized into the new-order generation, OHT vehicle dispatching, zone control, path decision, and tool processing agent models. Finally, the DAOPN is defined, and the modeling procedures of the intrabay behaviors are all illustrated. Consequently, an experimental intrabay OHT loop is discussed and evaluated using the proposed DAOPN models and the DAOPN simulator.

Object-oriented approach of MCTPN for modelling Flexible manufacturing systems

Manufacturing industry is facing a stricter challenge than ever before owing to the rapid change in market requirements. Flexible manufacturing systems (FMSs) have a much greater capability than traditional fixed-type production systems for coping with the rapid change. In this paper, a modified coloured-timed Petri net (MCTPN) is developed to model the dynamic activities in an FMS. The MCTPN provides an object-oriented and modular method of modelling manufacturing activities. It includes colour, time, modular and communication attributes. The features of object-oriented modelling allow the FMS to be modelled with the properties of classes, objects, and container trees. Since the system activities can be encapsulated and modularised by the proposed MCTPN, the manufacturing systems can be easily constructed and investigated by the system developers. It makes the concept of software IC possible for modelling complex FMSs. Once all of the MCTPN objects are well defined, the developers need to consider only the interfaces and operations relating to the MCTPN objects. In order to demonstrate the capability of the proposed MCTPN, the FMS in the Manufacturing Automation Technology Research Center (MATRC) of the National Taiwan University will be stimulated and justified by using the proposed MCTPN along with the G2 expert system.

System Modeling and Real-Time Simulator for Highly Model-Mixed Assembly Systems

In recent years, the automobile industry is facing more challenge than ever due to rapid model change requirements and demand fluctuations. Traditional fixed-type production systems are less capable in coping with the rapid change, while flexible production systems can better meet the requirement of low-volume production with model variations. Flexible machines integrated with model-mixed assembly lines form flexible assembly systems (FASs). In this paper, Colored Timed Petri Net (CTPN) is used to model a highly model-mixed automobile assembly system. Based on this CTPN model, a real-time simulator was developed along with different dispatching rules, Besides, the algorithm of balanced budget work standard (BWS) for a small batch production is developed for adjusting the loading balance of the operators in the highly model-mixed assembly lines. The simulator can be used as an effective tool for developing scheduling strategies.

Motion planning and control of interactive humanoid robotic arms

Humanoid robots are widely discussed in recent years. The motion planning and control of humanoid robots can be discussed based on mobility of platforms and manipulations of arms. In this paper, we propose a robotic arm which manipulation is analog to the motion of humanpsilas upper extremities. The proposed robotic arm is designed as a seven degree-of-freedom configuration. To increase the interactivity with humans, a six-axis force sensor is attached on the wrist of the robot to capture the force applied on the robotic arm. Subsequently, the robotic arm is moved following the force applied on the wrist. In addition to the compliance of humanpsilas motion, the robotic arm is capable of dynamically planning spatial trajectories for various straight lines, circles, or predefined paths. Especially, due to the structure of this seven degree-of-freedom robotic arm, we cannot find a unique solution for the inverse kinematics. In this work, we present a behavior based inverse kinematics approach to solve this problem in terms of the fuzzy reasoning. Various behaviors for a given spatial position or path, such as writing, pickup, etc., may result different inverse kinematic solution, and may generate different elbow trajectories as well. Therefore, the proposed robotic arm not only has similar structure to humans, but also represents similar behavior to humans. More specially, the compliance function makes this robotic arm possible to interact with humans. Consequently, a robotic arm with tendon driven architecture is demonstrated to validate the proposed motion planning and control approaches based on an ARM based controller.

Development of Autonomous Robotic Wheelchair Controller Using Embedded Systems

Autonomous robotic wheelchairs play important roles to disabled persons or elders. In general, an autonomous robotic wheelchair includes the techniques of obstacle sensing and avoidance, local path navigation, and friendly interactions with users when compared to conventional powered wheelchairs. Most of researches on autonomous robotic wheelchairs used the personal computer as the supervisory controller since its powerful computing capacity and familiar coding environment. Nevertheless, the personal computer is not feasible to the wheelchair users due to inefficient size, lower reliability and larger power consumptions. To promote feasible robotic wheelchair control architecture, the embedded system is surveyed in this paper. By using the embedded computing architecture, the proposed robotic wheelchair controller performs characteristics of compact size, better reliability and lower power consumptions while the benefits of powerful computing capacity and familiar coding environment are maintained. On the other hand, this paper also implements the fuzzy logic based autonomous navigation functions such as goal-seeking, wall-following and obstacle avoidance. Theses fuzzy logic based navigation functions are fused together to solve practical situations of the robotic wheelchairs. Finally, a real robotic wheelchair with three-omni- wheel configuration is constructed based on the proposed control architecture, and several practical experiments are also discussed in this paper.