2001 ieee/asme international Conference on
:10―17:30 Control of the Secondary Mirror Unit for the SOFIA Telescope
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- Environment-Contacting Task by Position-Controlled Manipulator using Free-Joint Structure
- Grinding Force Models in Finishing Processes
Control of the Secondary Mirror Unit for the SOFIA TelescopeJoseph Moerschell, HEVS, Emmanuel Onillon, CSEM, Switzerland SOFIA is a 2.5-m telescope to be carried on a special Boeing 747 for astronomic observations at altitudes of about 15'000 m. The paper describes the main features of the secondary mirror unit. The SOFIA secondary mirror needs active control for alignment along five degrees of freedom as well as for very fast chopping with a frequency up to 20 Hz. The SOFIA secondary mirror chopping mechanism and control system will be described in the following. A state space model derived from the mechanical and electrical equations of the system will then be introduced. This model will be used for the design of a state space controller based on a pole placement algorithm, to make the system behave as a fourth order Bessel filter. To avoid overshoots due to current and voltage limitation, a variable speed limitation, which is function of the position error, will be added to the controller. | |||||||
Environment-Contacting Task by Position-Controlled Manipulator using Free-Joint StructureYasumichi Aiyama, University of Tsukuba, Japan In general environment-contacting manipulation task such as assembly requires a force-controlled manipulator. In this paper a method is introduced to achieve environment-contacting task with a position-controlled manipulator. Additional mechanism with some free-joint mechanism on wrist of a manipulator reduces excessive inner force. We show conditions to reduce excessive inner force and to keep high rigidity of object. An experiment of graspless manipulation with free-joint mechanism is shown as an example of this research. | 17:30―17:50 | Robustness Evaluation of New Practical Control for PTP Positioning SystemsWahyudi, K. Sato, A. Shimokohbe, Tokyo Institute of Technology, Japan This paper presents robustness evaluation of the new practical control for point-to-point (PTP) positioning systems. The proposed controller consists of a nominal characteristic trajectory as an intended motion trajectory and PI elements which are used to restrict the plant motion along the trajectory. The nominal characteristic trajectory is determined with measured open-loop responses of the plant and is also used to determine the PI coefficients. So the proposed controller does not require an exact model of the plant and its parameters and is easily applicable to practical systems. The robustness of the proposed controller is evaluated and compared experimentally with conventional PID controllers using an experimental rotary positioning system. It is proved that the proposed controller is better than the … | |||||
Grinding Force Models in Finishing ProcessesYin-Tien Wang, Yann-Jyi Jan, Tamkang University Taiwan, ROC Force models and control for a robot-assisted surface finishing system are presented in this paper. These models are based on two different concepts, the theory of a linear observation and Grey theory. Integrated with an automated surface finishing system, these force models are designed as force observers to sense the grinding contact force based on the driving current and output position of the motor. In order to test the function of the force models, a robot-assisted finishing system is constructed and tested on a Tatung A530 robot. Also, we utilize Taguchi's method for experimental design to determine an ideal grinding condition. Four grinding conditions are chosen, namely, path pattern, grinding contact pressure, tool diameter, and feed rate. Tendencies of these factors can be found from the experiments. The experimental results show that the robot-assisted finishing … | 17:50―18:10 | GA-Based Evolutionary Design of Robust Compensator for Mechatronic SystemsMakoto Iwasaki, Kazuaki Itoh, Nobuyuki Matsui, Nagoya Institute of Technology, Japan This paper presents an evolutionary algorithm for the robust motion controller design in mechatronic systems using a Genetic Algorithm. The motion control system is composed of a robust 2-Degrees-Of-Freedom compensator based on the coprime factorization description. Conventional controller design approaches to the optimization for the compensator free parameters essentially require complicated numerical procedures under the given control specifications. In this research a simple and practical algorithm for the compensator design for mechatronic systems has been proposed. Using the optimization ability of the Genetic Algorithm the proposed algorithm is able to autonomously tune the optimal combination of the … | |||||
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