Matthias Rehm

Influence analysis on the model comparison performance index for servo drive control

The paper deals with the proposed performance index of [1], which can assess command action performance of a servo drive in terms of the parameterization of the comparison model. By reversing a tuning rule, the comparison model can be parameterized without any a priori knowledge, with the drawback of low significance for some controller detuning directions. The performance index is examined further regarding practical online usage as in a running production process here. Signal sampling is considered in terms of sample time and quantization. Excitation independence as a basic goal for a performance index is also examined. For a more realistic picture the index is calculated with the monitored system operated under cascaded position control. The influence of position command signal sequences with different jerk and acceleration parameters are analyzed. In conclusion the limitations of the performance index are discussed and required future work is discussed.

A Model Comparison Performance Index for Servo Drive Control

This paper describes an approach for monitoring closed loop speed control of electromechanical drives. The data of the closed loop is evaluated and concentrated to a performance index, giving a scalar value to measure setpoint change behavior. The method uses an order-reduced model as comparison basis to closed-loop signals, which is possible to implement on controller equipment. Parameterization of the comparison model is addressed even pointing out a provision without requiring a-priori knowledge. Influence of the main parameters is shown by means of simulation results. Following, experiments are carried out and compared to theoretical results. In conclusion usability and possible further improvement is discussed.

Control Strategies for Mechanically-Coupled High Speed Linear Drives

Vibration excitation of the machine structures caused by high speed drives often leads to production inaccuracies. By coupling two opposed driving and corporate acting linear drives in one drive train the static and dynamic properties can be improved. This arrangement offers the possibility to distribute the forces between both drives. Furthermore the impulse and jerk feedback into the machine structure can be minimized. In addition de-and acceleration energy can be saved in the coupling element. In order to guarantee the requirement for high accuracy in synchronous tracking as well as to realize pretension of both drives for high acceleration, control strategies and controller tuning methods are going to be discussed based on simulation results.

Comparison of Feed Drives with a Process Oriented Design Methodology

The paper points out a novel design methodology for electromechanical linear axis. It is based on common process parameters and an automated iterative solution algorithm. For the first time ever, different types of electromechanical linear axes can be compared. Furthermore, an optimum solution aiming a low moment of inertia ratio is the result of the design process. Using the example of a machining center, simulation and experimental results are shown. The performance of the process-oriented design methodology relating to additional design objectives is shown in this context.

Performance Index for Servo Drives under PI Speed Control

The paper points out a minimum variance based performance index for restricted controller structure, known in literature and applied in process industries. The theory is introduced briefly. As core of the paper adaption to the topic of speed control for electromechanical drives is shown. Simulational and experimental results for various single and dual-mass systems show good sensitivity to relevant parameters. As main drawback, the index prefers tough controller settings.

Control Structures for Opposed Driving, Coupled Linear Drives

In manufacturing linear motors are mainly used in the field of lightweight and highly dynamic drives. The high acceleration forces leads to vibration excitations of the machine structure that causes production inaccuracies. This can be improved by coupling two corporate acting and opposed driving linear drives in one drive train. The coupled structure can improve the static and dynamic properties by distributing the forces between both drives. In order to guarantee the requirement for high accuracy in synchronous tracking, control structures and controller tuning methods are going to be discussed based on simulation and experimental results.