Biaxial Platform Research Articles

Design and performance evaluation of an exponentially weighted moving average–based adaptive control for piezo-driven motion platform

In this article, building a controlled system with velocity feedback in the inner loop for a platform driven by piezoelectric motors is investigated. Such a motion control system is subject to disturbance such as friction, preload, and temperature rise in operation. Especially, temperature rise is an essential problem of using piezoelectric motor, but very few research works address this topic in depth. Exponentially weighted moving average method has been widely used in process control to deal with systematic change and drift disturbance. It is attempted to map the exponentially weighted moving average method and the predictor corrector control with two exponentially weighted moving average formulas into a run-to-run model reference adaptive system for velocity control. Using a predictive friction model, a dead-zone compensator is built that can reduce the friction effect and provide an approximately linear relation of the input voltage and the output velocity for the subsequent exponentially weighted moving average or predictor corrector control control design. Comparison of the exponentially weighted moving average, predictor corrector control, and proportional–integral–derivative controllers is carried out in experiment with different speed patterns on a single-axis and a bi-axial platform. The results indicate that the proposed run-to-run-model reference adaptive system predictor corrector control is superior to the other methods.

Simulation and Experimental Study of Ball Position Control at Biaxial Platform using State Space Approach

Ball on plate platform is a great tool for testing of various control techniques. This study provides a detailed design and comparison of three control structures for automatic stabilization of the ball´s location on plate and ball trajectory tracking. Namely PD controller, state space feedback and state space observer with state space feedback. All three methods are designed and practically compared. All structures have a common feature. It is the methodology for calculating the parameters of the controllers. Ball - on - plate mathematical model derived by Newton´s method and DC motor position loop control are also part of this article. For the authors of this article, this study is an opportunity to create an educative setup to explain the principles of basic control system for non - technical person and offers motivation to future students.

Stabilisation problem in biaxial platform

AbstractThe article describes investigation of rolling ball stabilization problem on a biaxial platform. The aim of the control system proposed here is to stabilize ball moving on a plane in equilibrium point. The authors proposed a control algorithm based on cascade PID and they compared it with another control method. The article shows the results of the accuracy of ball stabilization and influence of applied filter on the signal waveform. The application used to detect the ball position measured by digital camera has been written using a cross platform .Net wrapper to the OpenCV image processing library - EmguCV. The authors used the bipolar stepper motor with dedicated electronic controller. The data between the computer and the designed controller are sent with use of the RS232 standard. The control stand is based on ATmega series microcontroller.