An investigation into the dynamic modelling of flexible manipulator systems with different mechanical structures and actuation mechanisms is presented. Dynamic models of the systems are developed based on the assumed modes method considering linear displacements, quadratic displacements and the finite element method. Simulation and experimental exercises are performed with bang-bang torque and smooth displacement driven manoeuvres. To investigate the effects of centrifugal forces, slow and fast trajectories are implemented. Simulation and experimental results of the response of the flexible manipulators are presented in the time and frequency domains. Moreover, model validations are carried out by comparing the results to assess the performance of the modelling approaches.
In recent years, several solutions for structural vibration control of buildings have been proposed. In particular, the combination of base-isolated structures with complementary variable damping devices has been successful in reducing the base isolator displacements without increasing the building superstructure response when subjected to earthquake loads. In this paper, a magnetorheological device is installed on a 2-DOF mechanical model mounted on an experimental uniaxial shaking table. A simple numerical simulation model is derived for the experimental setup and it represents a typical base-isolated structure with a semi-active vibration controller. The control law combines a force tracking integral action with a clipped on–off adaptation rule that changes the magnetorheological damping in real time. The effectiveness of the proposed solution is demonstrated for both earthquake-like and real earthquake input ground motions. A comparison between the numerical and the experimental results validates the numerical simulations and it gives confidence in using this model for validation and evaluation of other semi-active control solutions based on magnetorheological dampers.