Active Microvibration Control of an Optical Payload Installed on the ARTEMIS Spacecraft

Abstract

This paper presents a feasibility study for the vibration control of the SILEX optical payload installed on the European ARTEMIS advanced telecommunication satellite. Due to its stringent pointing requirements (being approximately a few microradiants) the payload is particularly sensitive to the transmitted microvibrational disturbances. The vibration suppression problem has been addressed using piezoceramic strain actuators bonded to the payload support structure and designing a high control authority linear quadratic compensator. The plant mathematical model was obtained through a NASTRAN finite element modeling of the payload structure equipped with the surface bonded piezoceramic strain actuators. This high order evaluation model has successively been reduced to a lower order design model using static condensation (Guyan) and modal reduction techniques. Different criteria have been applied in order to check for the controllability of the system. The LQR compensator design was based on the minimization of a quadratic performance index of state and control vectors which included the output behavior. A comparison between the open and closed loop system behavior was carried out for different disturbance inputs and different control weights.

Nonlinear deformations of piezoelectric composite beams

“…(1) 1 ,,  3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 19 of a cantilever beam with two pairs of piezoelectric patches can be seen by comparing configuration of the actuated beam in figure 7. The materials properties of the components are considered as E b =4.9 GPa, E p =38.6 GPa, d 12 =0.18nm/V, β 12 =8 (pm/V) 2 where the linear and nonlinear piezoelectric coefficients are those reported for PZT G-1195 [17]. The segments of the beam with patches are drawn with thicker lines.…”

“…There have been several studies on analyzing deformations in elastic beams and plates having distributed piezoelectric patches, which are used in vibration controls, acoustic applications, and noise control systems [1]. For example, by using piezoelectric actuators, dynamic performance of aerospace structures are controlled through increasing damping of the structure and decreasing vibration amplitudes [2]. Most of these studies only consider small deformations in the active structures and relatively small amplitude of electric field is needed for vibration suppression.…”

Static adjustment of beam deflections by means of induced strain actuators

“…Some experiments have been conducted both on earth and in orbit [6] to assess the role of this technology in view of the more restrictive requirements in terms of dynamic structural performance. One typical example is the control on the pointing requirements of optical payloads mounted on space platforms [7]. More recently some studies have directed their attention to the problem of static adjustment, such as the case of space structures subjected to severe thermal actions.…”