Rickey Dubay

Finite element based model predictive control for active vibration suppression of a one-link flexible manipulator

This paper presents a unique approach for active vibration control of a one-link flexible manipulator. The method combines a finite element model of the manipulator and an advanced model predictive controller to suppress vibration at its tip. This hybrid methodology improves significantly over the standard application of a predictive controller for vibration control. The finite element model used in place of standard modelling in the control algorithm provides a more accurate prediction of dynamic behavior, resulting in enhanced control. Closed loop control experiments were performed using the flexible manipulator, instrumented with strain gauges and piezoelectric actuators. In all instances, experimental and simulation results demonstrate that the finite element based predictive controller provides improved active vibration suppression in comparison with using a standard predictive control strategy.

A principal component analysis model-based predictive controller for controlling part warpage in plastic injection molding

Quality measurement on injection molded parts are related to process parameter data.The data experimentation data is analyzed using statistical methods (PCA), (ICA) and (ANOVA).Models are constructed to predict a quality index based on data analysis results.A MPC scheme that allows for on-line quality control was developed using the models.The presented scheme is extendable to a variety of manufacturing processes. Quality control is an important aspect of manufacturing processes. Product quality of injection molded parts is influenced by the injection molding process. In this study statistical tools were used to develop a model that relates injection molding process variables to part quality. A statistically based model predictive control algorithm was developed for controlling part quality with manipulated variables coolant flow rate and coolant temperature. This approach replaces the need of off-line quality measurement and provides real-time injection modeling quality control.

A Concept for Docking a UUV With a Slowly Moving Submarine Under Waves

Docking an unmanned underwater vehicle (UUV) with a submerged submarine in littoral waters in high sea states requires more dexterity than either the submarine or streamlined UUV possess. The proposed solution uses an automated active dock to correct for transverse relative motion between the vehicles. Acoustic, electromagnetic, and optical sensors provide position sensing redundancy in unpredictable conditions. The concept is being evaluated by building and testing individual components to characterize their performance, errors, and limitations, and then simulating the system to establish its viability at low cost.

Model Predictive Control of Vibration in a Two Flexible Link Manipulator — Part 2

A model predictive controller (MPC) in the form of dynamic matrix control (DMC) is implemented for attenuating in-plane vibrations of a two flexible link planar manipulator. The rotation of the joints and inertia effect of both the joints and links induce vibration. Piezoelectric actuators, mounted in a bimorph configuration, provide the control actions to reduce vibrations. Implementation of this control scheme is shown to provide appreciable attenuation of vibration over the uncontrolled case, increasing the damping ratio for the first and second link by a factor of 5.99 and 3.40, respectively. DMC control is further shown to reduce the mean amplitude of dominant vibrations from the uncontrolled case by 90.0% and 87.4%, respectively, for the first and second links. Furthermore, for the two link setup, this control is shown to outperform the more conventional ProportionalIntegral-Derivative (PID) control and is sufficiently robust to handle an unknown payload.