Papers by Author: Marco Ceccarelli

Abstract: For stability and impact reaction forces assessment of a quadruped robot during walking, a dynamic analysis is considered. For this purpose, a variant of a quadruped robot based on Jansen mechanism is presented. For interpreting the influence of the reaction forces from the ground during walking, the analysis was conducted with help of ADAMS software using a 3D model of the robot. Material specifications, forces and moments acting in the robot structure were considered. Graphical results obtained regarding the ground reaction forces are displayed. Also a reduced mass moment of inertia at the crankshaft is taken into consideration based on Lagrange motion equation and generalized coordinates.

Abstract: In this paper an experimental research was performed in case of a human rehabilitation exoskeleton. The research aim was to evaluate the joint trajectories and the influence of the ground-foot contact by using two distinctive shapes of the exoskeleton foot. Thus an experimental motion analysis was used, called CONTEMPLAS and an exoskeleton prototype with 1DOF placed on a treadmill. The experimental activity was developed when the exoskeleton was used on walking activity. There were studied two types of foot shapes and also the generated impact of their form on the hip, knee and ankle joints trajectories during walking. The obtained results will be useful for the improvement of the exoskeleton orientation in space.

Abstract: The dynamic balancing of a spatial parallel manipulator of three degrees-of-freedom, CaPaMan-2 (Cassino Parallel Manipulator 2), by the application of Counter-Rotary Counterweights (CRCW) is analyzed. To accomplish this objective the mass and inertia of the moving platform are dynamically replaced by point masses located at the points of attachment of the legs to the platform and the mechanism is balanced by considering each of the legs independently. This fully parallel manipulator has three identical legs, each one composed by a four-bar mechanism (an articulated parallelogram) connected to the fixed base, and a link supported by the coupler that connects to the mobile platform. This link, seen as a pendulum, is transformed to a dynamic balancer using a Counter-Rotary Counterweight in order to compensate the motion of the moving platform. In a second stage the articulated parallelogram is modified by adding Counter-Rotary Counterweight plus a Counterweight to dynamic balance its part of the system. As a final result it is obtained a new design, with a parallel manipulator dynamic balanced. The resulting model of the manipulator is validated by dynamic simulation, using general purpose software for the analysis and dynamic simulation of multi-body systems (ADAMS).

Abstract: In this paper an algebraic formulation is proposed for designing telescopic manipulators when workspace is prescribed in a suitable form. An algorithm has been outlined by using an algebraic formulation for the workspace boundary.