Simultaneous optimization of structure and control for time-optimal motion of vibratory mechanical systems

การหาความเหมาะสมที่สุดของโครงสร้างและการควบคุมควบคู่กันสำหรับการเคลื่อนที่ที่เหมาะสมเชิงเวลาของระบบสั่นเชิงกล

Name: Boonruk Suchaitanawanit

ThaSH: Mechanical vibration

Classification :.DDC: 620.3

ThaSH: Mechanical engineering

ThaSH: Mechanical movements

ThaSH: Control theory

Abstract: This thesis considers the problem of time-optimal motion control of a mechanical vibratory system for which dynamical properties can be optimized through structural design. The problem is challenging due to the complexity in achieving precise positional changes of a flexible structure without causing residual vibration. The problem formulation is based on an actuated flexible mechanical structure undergoing a motion task with specified boundary conditions and subject to limits on control input (actuation force). A convex optimization method is proposed for calculating the minimum-time control input solution for given boundary conditions. The algorithm uses an iterative construction of the reachable set and is applicable for solving the minimumtime state transition problem for any linear system satisfying certain conditions of controllability and subject to limits on control input that are not state dependent. By gathering a set of minimum-time solutions for motion control problems involving different system properties and boundary conditions, the overall characteristics are analyzed and discussed in terms of achievable performance. This serves as motivation for the proposed structure/control optimization concept. Continuity properties of the solution set allow a first order perturbation analysis to be undertaken for variation in parameter values embedded in the system model. From this, an optimization of system design parameters can be achieved. The feasibility of the control approach is verified on an experimental system involving a linear motion stage with tunable-stiffness flexiblearmature. A method to implement the time-optimal control solutions obtained from the model-based calculations is presented. The simultaneous optimization method is applied in order to further reduce time of motion by tuning the natural frequency of the armature to match the boundary conditions for the motion task. The proposed convex optimization method was shown to be capable of calculating complex time-optimal control solutions without requiring any initial assumptions about the number of switches in control input value. The method was also successfully applied to a nonlinear system model that includes Coulomb friction effects. Furthermore, by matching the system design parameters with the boundary conditions, the simultaneous optimization approach allows significant reductions in time of motion to be achieved. However, the exact level of reduction depends on the task boundary conditions and initial design choice for the structure.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Wichaphon Fakkaew

Role: Chairman

Name: Matthew O.T. Cole

Role: Member

Name: Natee Tongsiri

Role: Member

Name: Theeraphong Wongratanaphisan

Role: Member

Name: Radom Pongvuthithum

Role: Member

Created: 2016

Modified: 2017-10-30

Issued: 2017-10-30

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 620.3 B724S

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Mechanical Engineering)

Grantor: Chiang Mai University

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