Dynamic Modeling and Vibration Control of a Single-link Flexible Manipulator Using a Combined Linear and Angular Velocity Feedback Controller

Download or read book Dynamic Modeling and Vibration Control of a Single-link Flexible Manipulator Using a Combined Linear and Angular Velocity Feedback Controller written by Kerem Gurses and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of lightweight, thin flexible structures creates a dilemma in the aerospace androbotic industries. While increased operating efficiency and mobility can be achieved byemploying such structures, these benefits are compromised by significant structuralvibrations due to the increased flexibility. To address this problem, extensive research inthe area of vibration control of flexible structures has been performed over the last twodecades. The majority of the research has been based on the use of discrete piezoceramicactuators (PZTs) as active dampers, as they are commercial availability and have highforce and bandwidth capabilities. Many different active vibration control strategies havepreviously been proposed, in order to effectively suppress vibrations. The synthesizedvibration controllers will be less effective or even make the system to become unstable ifthe actuator locations and control gains are not chosen properly. However, there iscurrently no quantitative procedure that deals with these procedures simultaneously. This thesis presents a theoretical and numerical study of vibration control of a singlelinkflexible manipulator attached to a rotating hub, with PZTs bonded to the surface ofthe link. A commercially available fibre optic sensor called ShapeTapeTM is introduced asa new feedback sensing technique, which is complemented by a quantitative anddefinitive model based procedure for selecting the individual PZT locations and gains. Based on Euler-Bernoulli beam theory, discrete finite element equations are obtainedusing Lagrange's equations for a PZT-mounted beam element. Slewing of the flexiblelink by a rotating hub induces vibrations in the link that persist long after the hub stopsrotating. These vibrations are suppressed through a combined scheme of PD-based hubmotion control and proposed PZT actuator control, which is a composite linear (L-type)and angular (A-type) velocity feedback controller. A Lyapunov approach was used tosynthesize the PZT controller. The feedback sensing of linear and angular velocities isrealized by using the ShapeTapeTM, which measures the bend and twist of the flexiblelink's centerline. Both simulation and experimental results show that tip vibrations aremost effectively suppressed using the proposed composite controller. Its performanceadvantage over the individual linear or angular velocity feedback controllers confirmstheoretical predictions made based on a non-proportional damping model of the PZTeffects. Furthermore, it is demonstrated that the non-proportional nature of the PZTdamping effect must be considered in order to bound the range of allowable controllergain values.