Aktive Schwingungskontrolle einer Spannbandbrücke mit pneumatischen Aktuatoren

Abstract

Zur Bestätigung der modellbasierten Regelungen und der analytischen Modelle wird die aktive Schwingungskontrolle an der entwickelten Spannbandbrücke mit CFK-Lamellen realisiert. Der Vergleich der Ergebnisse aus der Simulation und dem Experiment nach einer definierten Anregung veranschaulicht die Qualität der analytischen Modelle und Regelungen. Unter fußgängerinduzierten Schwingungen bestätigen sich sowohl die Funktionsfähigkeit in der Praxis als auch das Potential aktiver Systeme zur Schwingungskontrolle. Die Beschleunigungsamplituden werden effizient auf ein komfortables Maß reduziert. Letztendlich zeigen die Ergebnisse, dass aktiver Leichtbau der Vision "null" Bauhöhe und "unendliche" Steifigkeit einen Schritt näher kommt.-VI --VII - AbstractNew materials and technologies allow not only the building of ultra-light and slender bridges, they also enable the construction of sustainable bridges. Aiming at a reduction of their more complex and high vibration sensitivity, a new active vibration control approach was developed and applied to a prototype; both will be presented in this thesis. By using highstrength carbon fibre reinforced plastic (CFRP), a very light and flexible stress ribbon footbridge having a span of 13 m and a structural height of only 1 mm was built in the lab of the Chair of Conceptual and Structural Design of the Berlin Institute of Technology. The highstrength CFRP ribbons are ideally suited for this purely tensioned bridge. However, the extremely low extensional stiffness of the optimally designed and exploited CFRP cross section as well as the bridge's extremely low structural damping, even under ordinary pedestrian traffic, lead to an unusually high vibration sensitivity in several modes.In order to counteract the high level of pedestrian-induced vibrations, an active vibration control concept is developed. This concept includes the embedding of smart actuators into the handrail, which is required anyway. Here, biologically inspired, extremely light and powerful artificial muscles are used. These pulling only actuators generate damping forces during the upward movement of the vibrating bridge. An active vibration control system consists of actuators, sensors and a controller. The multi-variable control concept is based on a cascaded control consisting of subsidiary loops to control the force of the pneumatic muscles and the outer loop to finally control the first three vertical modes of the bridge. The design of both controls is model-based.First, a reduced discretized analytical model for the stress ribbon bridge is developed. To verify the analytical prediction, experiments without control are conducted. They show that a linearized 8-plate-model describes the natural modes and frequencies sufficiently exact. Secondly, the force control of the actuator system is based on a nonlinear analytical model of the pneumatic muscle, the valve characteristic and the pressure build-up. To handle the nonlinearities of the actuator system, a nonlinear force controller is designed based on exact linear...

Development, realization, and experimental validation of an active hybrid roof structure based on elastic kinetic and rigid-body transformation

“…Recent investigations of lightweight but non-transformable structures yet again proofed the effectiveness of static and dynamic adaptation. 30–36…”

“…Bleicher 31 experimentally investigated active vibration control to counteract pedestrian-induced vibrations of a CFRP stress ribbon footbridge. Using lightweight pneumatic muscle actuators integrated into the handrail, a multi-modal vibration damping was achieved.…”

“…For a comprehensive overview of structural control, which mainly refers to dynamic adaptation, see for example, Housner et al 28 and Saaed et al 29 Recent investigations of lightweight but non-transformable structures yet again proofed the effectiveness of static and dynamic adaptation. [30][31][32][33][34][35][36] Teuffel 30 developed a load path management method, that allows the design of minimum weight adaptive truss structures. Within this method, load transfer mechanisms and deformation behavior under variable loads can be optimized.…”

An Actuator Concept for Adaptive Concrete Columns

“…Most prototypes use linear actuators to manipulate the structural behavior, for example, hydraulic [16,21], pneumatic [22] or electromechanical actuators [13]. While these industry standard actuators present a solution that is economical and easy to implement, it may be not the most efficient.…”

Investigation of a large‐scale adaptive concrete beam with integrated fluidic actuators

“…16 Investigation of beam structures that react to bending loads by means of adjustable prestressing is given in Schnellenbach-Held et al 17 Hydraulic actuators are employed to tension an external cable system to reduce displacements under vertical loads. In Bleicher 18 a stress ribbon bridge is presented in which pneumatic actuators are installed in the handrail and the actuation force is thus introduced into the structure via the surface. The actuators reduce vibrational motion.…”