Martin Goubej

Kalman filter based observer design for real-time frequency identification in motion control systems

The paper deals with a systematic observer design for a robust frequency identification of electromechanical systems. The observer estimates the frequency response of the system which is excited by a swept harmonic signal with a variable frequency, amplitude and DC component. The paper presents a computationally efficient algorithm based on the recursive discretization of a Kalman filter. An application of the proposed method is demonstrated on a problem of motion control of a compliant mechanism.

Robust PID Control of Electrical Drive with Compliant Load

Abstract This paper deals with motion control of an electrical drive with a compliant load. Particular problem of velocity PID control is studied due to the extensive use of this control scheme in the industrial drives. The partial pole-placement method is used for the derivation of a feature-based parametrization of a set of stabilizing controllers which provide an active vibration damping functionality. Achievable quality of control is evaluated by means of proper performance indices in the form of H ∞ norm of important closed loop transfer functions. Simulation experiments demonstrate the application of the proposed method.

Feature-based Parametrization of Input Shaping Filters with Time Delays

Abstract This paper deals with signal shaping filters in form of sum of weighted time delays. The filter can be used to solve various control problems. The first important application is a control of flexible mechanical systems with respect to minimization of excited residual vibrations. The second interesting field is feedback controller design using open loop frequency response shaping. The paper presents an algorithm for parametrization of all equidistant four-pulse shaping filters with minimum set of chosen parameters.

Robust frequency identification of oscillatory electromechanical systems

The paper deals with identification of electromechanical systems with oscillatory dynamics. Swept sine signal is chosen for excitation of the system and time-varying observer is used for estimation of its frequency response. Practical implementation issues for various mechanical configurations typical for industrial applications are analyzed and concept of frequency-separated semi-closed loop identification is proposed. Adaptive algorithm which suppresses nonlinearities of the system due to mechanical friction and estimates actual quality of measurement is derived. The identification method is demonstrated on an example of two-mass oscillatory system with nonlinear load-side friction characteristics.

Unified framework for generation of 3D web visualization for mechatronic systems

The paper deals with development of a unified framework for generation of 3D visualizations of complex mechatronic systems. It provides a high-fidelity representation of executed motion by allowing direct employment of a machine geometry model acquired from a CAD system. Open-architecture multi-platform solution based on latest web standards is achieved by utilizing a web browser as a final 3D renderer. The results are applicable both for simulations and development of real-time human machine interfaces. Case study of autonomous underwater vehicle control is provided to demonstrate the applicability of the proposed approach.

Advanced input shaping filter 3D virtual laboratory

In this paper, a 3D virtual laboratory presenting all features of advanced input shaping filter is described. By proper choice of filter coefficients, various design requirements can be achieved (damping at given frequencies, bandwidth, robustness to uncertainties, etc.). Hence, one can handle the trade-off between the filter performance and signal delay which is added to the loop. The filter principle can be evaluated on gantry crane 3D model by using virtual laboratory. The control aim is to avoid load oscillations during load transport. The shaping filter works as a band stop filter which attenuates the natural frequency by modifying setpoint changes. The 3D crane model development is based on Java3D package (rendering package) and a VRML (Virtual Reality Modeling Language) Java loader which creates a bridge between the CAD system and the rendering engine. The interactive tool is freely accessible at www.contlab.eu. The authors believe that the virtual lab may be useful for both academic and industrial sphere.

Dynamic analysis and control of robotic manipulator for chemically aggressive environments

The paper deals with newly developed industrial robotic manipulator with special serio-parallel architecture which was designed for operation in chemically aggressive environment. Dynamical analysis of the manipulator is performed for the purpose of control law synthesis. General method for derivation of static models is presented.

Active vibration control of two-mass flexible system using parametric Jordan form assignment

Abstract This paper deals with stage motion control system for scene manipulation during theater performance. Particular task of rope drum control is presented and solved. The system exhibits an oscillatory dynamics due to the elasticity of the rope with a hanging load. The goal was to find a simple control strategy based on a common cascade PID structure which is available in most of the industrial AC drives. Formerly developed method of parametric Jordan form assignment was used to solve the problem and obtain simple tuning rules.

Fundamental performance limitations in PID controlled elastic two-mass systems

The paper deals with analysis of fundamental performance limitations of elastic servo drives with significant mechanical compliance in the driven load. Two-mass system is chosen as a general representation of a flexible mechanism with oscillatory dynamics. A problem of PID compensator tuning is considered since this control algorithm is still prevalent in industrial motion control systems. The provided analysis reveals an essential importance of the resonance ratio parameter and derives its range suitable for convenient controller design. The theoretical analysis is supported by experimental results.

Non-parametric frequency response estimation of two-mass-system using Kalman filter

This paper studies an online nonparametric identification method that is based on a time-frequency representation of signals using Kalman filter. The method utilizes swept excitation signal by synchronizing the Kalman filter to the frequency of the excitation signal generator and updating the filter gains on a sample-by-sample basis. Four different closed loop identification configuration are studied and experimentally compared by considering direct and indirect identification approaches. Moreover, this paper studies loop transfer function estimation from the closed loop controlled servomechanism and discusses the possibility to use the result for loop diagnostics. The experimental results illustrate the effectiveness of the studied online identification method to estimate nonparametric frequency response of the closed loop-controlled servomechanism at a selected band of frequencies.