Manfred Enning

Automation of a laboratory plant for direct casting of thin steel strips

Abstract The automation of a double roller laboratory plant for continuous casting of thin steel strip is described. A nonlinear state-space process model which represents the dynamics of the solidification and forming process has been developed. Based on this model the control concept using the force as the controlled variable has been derived and applied to the plant. Furthermore, starting the process which is difficult to handle is treated as an optimization problem. The solution to this task is given as a nonlinear two-point boundary value problem which is solved by means of a gradient method. A multi-microcomputer system based on the AMS-Bus has been developed to handle the variety of all tasks of automation at the laboratory plant.

Longitudinal Control of Following Vehicles within Platoon: A Model-Based Predictive Approach

Abstract This paper demonstrates via analysis and simulation, the feasibility of a vehicle-follower control system for vehicles within platoon using a model-based predictive approach for the control law. The demand for string stability and the minimisation of fuel consumption are shown to be achievable when the control law includes an appropriate combination of spacing policy and communication structure. The longitudinal control law presented in this study takes advantage of communication possibilities not available in the recent past. It assumes for example, that a following vehicle knows the states of the lead vehicle in addition to those of the preceding vehicles every time. A control law is developed and tested on a simulation of a platoon of 5 vehicles where the lead vehicle changes its velocity according to a predetermined cycle. This study is an extension of the interdisciplinary project Einsatzszenarien fur Fahrerassistenz Systeme im Guterverkehr umd deren Bewertung (EFAS), supported by the German Federal Ministry for Education and Research. Within the framework of this project a longitudinal state space controller for a heavy-duty vehicle within platoon was developed and tested with Matlab/Simulink by the Institute of Automatic Control (IRT) of Aachen University.

Wheelslide and Wheelskid Protection for a Single-Wheel Drive and Brake Module (SDBM) for Rail Vehicles

In this paper, the dynamic behaviour of a rail vehicle with single-wheel drive and brake modules is analysed. It is shown that in the wheelslide or wheelskid case, the linearised plant obtains an unstable pole whose location is determined by the shape of the current creep force curve. By considering possible variations in the shape of the creep force curve, the corresponding variation of the pole location in the right-half plane is calculated and a controller structure for creepage control and creep velocity control is suggested. If the controller design takes the worst-case pole location into account, the resulting controller stabilises the closed loop even at small velocities. Finally, this fact is illustrated through simulation results.

Nonlinear spacing control of following vehicles within platoon a controlled lagrangian approach 1

Abstract The spacing control law presented in this paper takes advantage of the technique of geometric nonlinear control of Lagrangian systems in order to achieve the demand for string stability. The procedure involves making structured modifications to the Lagrangian for the uncontrolled system, thereby constructing the controlled Lagrangian. In addition the energy method is used to find control gains that yield closed-loop (Lyapunov and asymptotic) stability for an individual vehicle within platoon. The feasibility of a nonlinear string stable vehicle-follower control system is demonstrated in a simulation of a platoon of vehicles using Matlab/Simulink.

Creepage control for use in wheelslide protection systems

Abstract In order to achieve acceptable braking distances, the wheelslide protection controller of a railway vehicle should hold an operating point in the macro-slip range on the decreasing branch of the creep force curve. Based on mathematical models of the railway vehicle, the creep force characteristics and the brake system, a stability analysis is performed for the open-loop system during braking in the macro-slip range. In addition, a creepage controller that stabilises the closed loop over the entire vehicle velocity range is presented and its performance is discussed with the help of simulation results.

Flatness Based Control of Inductive Heating of X210CrW12 into the Semi Solid State

The inductive heating of the feedstock material is a very important step in the processing of semi solid metals. On the one hand, the billet has to be heated as fast as possible to the target temperature. On the other hand, it must be guaranteed that the outer area does not begin to melt prematurely. Also, at the end of the heating the billet should have an uniform temperature distribution in order to obtain good forming results. A flatness based control will be presented to calculate the induced power over time trajectory from a desired trajectory for the temperature in the middle of the billet. The temperature trajectory has to be chosen so that the billet has the desired temperature behaviour. Experimental results will be shown for the flatness based inductive heating of X210CrW12 just below the semi solid state.

Adaptiver Gleitschutz für Schienenfahrzeuge (Adaptive Wheelslide Protection System for Railway Vehicles)

Abstract Dieser Beitrag beschäftigt sich mit der Auslegung und dem Test einer Gleitschutzregelung für Schienenfahrzeuge. Als Grundlage für die Reglerentwicklung werden zunächst einfache Modelle des Schienenfahrzeugs, der Kraftschlussbeanspruchung und des Bremssystems vorgestellt. An Hand einer Analyse des Gesamtmodells kann der Wertebereich eines bestimmten Modellparameters berechnet werden, der bei der Auslegung des linearen, robusten Schlupfreglers berücksichtigt werden muss. Daneben wird die Adaption der Reglerverstärkung an einen leicht zu identifizierenden Fahrzeugparameter (Bremszustandsfaktor) beschrieben. Schließlich werden Versuchsergebnisse von Testfahrten mit einer Regelung im Mikroschlupfbereich vorgestellt und diskutiert.

Automation of a Laboratory Plant for Direct Casting of Thin Steel Strips

Abstract The automation of a double roller laboratory plant for continuous casting of thin steel strip is described. A nonlinear state-space process model which represents the dynamics of the solidification and forming process has been developed. On the basis of the model a process controller with the force as the controlled variable has been designed and applied to the laboratory plant. This controller ensures the production of steel strip with tolerable variations in thickness. Furthermore, starting the process which is difficult to handle is treated as an optimization problem. The solution to this task is given as a nonlinear two-point boundary value problem which is solved by means of a gradient method. A multi-microcomputer system based on the AMS-Bus has been developed to handle the variety of all tasks of automation at the laboratory plant.

Flexibles Automatisierungssystem für eine Versuchsanlage zum Gießwalzen von Stahlband

Die Regelung eines noch vollkommen unbekannten Prozesses, etwa im Rahmen der Automatisierung einer Versuchsanlage, stellt den Regelungstechniker haufig vor das folgende Problem: Ein Betrieb ohne Regelung ist nicht moglich, da der Prozes stark gestort oder moglicherweise sogar instabil ist, die notwendigen Erkenntnisse fur eine zufriedenstellende Regelung konnnen aber erst durch Messungen im laufenden Betrieb gewonnen werden.

Hierarchical computer control system for continuously operating large distribution systems

Abstract The concept of an automatic control system for a distribution system for solid matter was developed by a systematic approach. The advantage of this is its very clear structure which supports a realization with a distributed computer control system. The basic idea is the application of balance control loops for every level of the tree-formed structure. Thus the internal structure of the distribution system beyond a branch can be hidden from the respective superior levels (principle of aggregation) and the problems of the couplings between all control loops can be solved. The grouping of the total control tasks on different levels leads to a concept for the realization of the automation system with Programmable Logic Controllers (PLCs).