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Interaction Map 1

Interaction Map 1 31.10.2007 Short Term Shutter and Long Term Shutter 4 – FUNDAMENTALS Electromagnetic Magnet properties Coil properties Back-EMF damping Mechanical Thermal FH properties ti Heat conduction Eigenfrequencies Thermal radiation Shutter installation Glue heat conductivity Figure 4.8: Map of the physical interactions separated in the mechanical, electromagnetic and thermal branches. DIVISION Science & Earth Observation 4.4 Interaction Map In the previous sections, the mechanical and electromagnetic basics for the MSTS design were discussed. However, no introduction in the thermal basics is given due to its reduced significance for the DM during the preliminary design phase. Nevertheless, a thermal analysis, which served its purpose, was performed and will be discussed in chapter 5.1. As a summary of the physical interactions, which lead the MSTS design, figure 4.8 shows an interaction map with indicated parameters of the concerning physical branches. This figure shall point the designing difficulties for fulfilling all requirements. Recip- rocal relations of different parameters in the electromechanical equations do not allow a straightforward design approach, but rather require good optimizations. 26

4.5 Control 4.5.1 Introduction 4 – FUNDAMENTALS A shutter blade switching mode with a maximum close/open time for the MSTS movement is defined in table 2.1. Thus, an adequate electronics which controls the blade stroke is required to achieve this mode. Applicable fundamentals of the control theory will be introduced here in view of defin- ing the control parameters, which must be finally converted into electric resistances and capacitances respectively. w - e Controller y z Control Path Figure 4.9: Standard closed loop system [7]. Figure 4.9 shows the standard closed loop system subdivided in the controller, the con- trol path and its characterizing feedback comparator. The parameters are well known as x control variable, w set point, e error signal, y actuating variable and z disturbance variable. The electronics shall perform all parts of the standard closed loop system excepting the control path, which is composed by the FH and the VCA. x 27