Flavio Bonfatti, Università di Modena e Reggio Emilia, Gianni Gadda, DemoCenter, Paola Daniela Monari, Università di Modena e Reggio Emilia, Italy
The paper introduces a software design method to pursue modularity of PLC-based system control code. Modularity is a critical condition to support co-operative development of complex systems, where components supplied by a number of subcontractors are integrated to realize the envisaged plant. The method proposes a disciplined use of the SFC, FBD and ST languages of the IEC 61131-3 standard.
Vibration Condition Monitoring of Rotors on AMB Fed by Induction Motors
Nicola Amati, Eugenio Brusa, Politecnico di Torino, Italy
The presence of induction driver motors in rotors on AMB can affect significantly the vibration monitoring operation because of the effect of the so-called unbalanced magnetic pull (u.m.p.) on the rotor whirling cage. A sort of beat appears in monitored radial displacements caused by the interaction between the unbalance response of the rotor and the u.m.p. depending on the slip occurring in the induction motor. This effect is herewith preliminary analysed in the range of spin speeds where the rotor behaves as a rigid body. The equations of motion of the system include the negative stiffness provided by the motor in presence of non uniform air gap and are written under the assumptions of linearized forces for the AMB and rotor axis-symmetry. Some experiments have been performed to validate the …
15:10―15:30
Continuous Testing as a Strategy of Improving the PLC Software Development Cycles
Ulrich Kramer, Bielefeld University of Applied Sciences, Germany
An appropriate simulation environment for testing real-time software applications, especially PLC (PLC: Programmable Logic Controller) programs, is demanded in recent time for many reasons. One of the them might be found in the altered conditions of cooperation (teamwork, teleworking, etc.) under which PLC software projects have to be carried out. Most areas of automation engineering lack for largely formalizable procedures, in particular within the specification and testing phase, and almost no tools are available for the development of real-time software. The consequence is that PLC programs are usually not developed before the facility to be controlled is installed, and putting it into operation is often the only test. The results are unacceptable waste of time during the installation phase, …
Identification with Blended Multi-Model Approach in the Frequency Domain: an Application to a Servo Pneumatic Actuator
H. Schulte, H. Hahn, Universität Kassel, Germany
By means of an real world application a system identification method was investigated for nonlinear systems from input-output measurements. This approach based on an blended multiple model structure which describes the global behaviour of the system over the whole operating range. At different operating points twenty local linear black-box models were identified in the frequency domain from a finite number of measurements of the input and output signals. A comparative study was made of a grey-box model which have been derived using physical laws and measurements of several process states to estimate unknown parameters.
15:30―15:50
Object―Oriented Approach to PLC Software Design for a Manufacture Machinery Using IEC 61131-3 Norm Languages
Marcello Bonfè, Cesare Fantuzzi, Università di Ferrara, Italy
This paper presents an application of object – oriented methodology to the development of Programmable Logic Controller (PLC)programs. PLC is widely used as computer controller of manufacturing machinery, principally because its robustness and programming simplicity. During the last years, IEC 61131-3 norm has been introduced aiming to provide standard languages and structure to the development environments of PLC programmes, that are instead strictly bound up to now to proprietary languages. Following IEC 61131-3 prescription, is it also possible to develop well structured, object–oriented control software, which was hardly possible with the former vendor–speci .c low–level languages. This paper describes an application of the novel standard IEC 61131-3 to the development …
Dynamically Compensated Cams for Rigid Cam-Follower Systems with Fluctuating Cam Speed and Dominating Inertial Forces
B. Demeulenaere, J. De Schutter, KU Leuven, Belgium
Traditionally cam-follower systems are designed by assuming a constant camshaft speed. Nevertheless all cam-follower systems especially high-speed systems exhibit some camshaft speed fluctuation (despite the presence of a flywheel) which causes the follower motions to be inaccurate. This paper therefore proposes a novel design procedure that explicitly takes into account the camshaft speed variation. The design procedure assumes that (i) the cam-follower system is conservative and (ii) all forces are inertial. The design procedure is based on a single design choice i.e. the range of camshaft speed variation and yields (i) cams that compensate for the inertial dynamics for any period of motion and (ii) a camshaft flywheel whose (small) inertia is independent of the period of motion. A design example shows …
15:50―16:10
Development of a Distribution VR-Based Complex Graphics Design System
Wen-Tsai Sung, Shih-Ching Ou, National Central University Taiwan, ROC
