Hagay Bamberger

On the dynamic pull-in of electrostatic actuators with multiple degrees of freedom and multiple voltage sources

This study considers the dynamic response of electrostatic actuators with multiple degrees of freedom that are driven by multiple voltage sources. The critical values of the applied voltages beyond which the dynamic response becomes unstable are investigated. A methodology for extracting a lower bound for this dynamic pull-in voltage is proposed. This lower bound is based on the stable and unstable static response of the system, and can be rapidly extracted because it does not require time integration of momentum equations. As example problems, the dynamic pull-in of two prevalent electrostatic actuators is analyzed.

Assembly Mode Changing in Parallel Mechanisms

Parallel mechanisms usually have several direct kinematic solutions that are attributed to different assembly modes (AMs) or postures. The present investigation deals with AM changing, and shows that beside the known cusp points, it is possible to change AM by moving on a path like a ramp, while encircling an alpha-curve in the joint space. For micromechanisms, where clearances at the mechanism joints are relatively large, AM changing may also occur when approaching a direct kinematic singularity.

A Novel Six Degrees-of-Freedom Parallel Robot for MEMS Fabrication

This paper introduces a new architecture of a six degrees-of-freedom parallel robot suitable for microelectromechanical systems (MEMS) fabrication. The robot consists of only revolute joints for the passive joints, and linear actuators located at the base for the active ones, both of which are easier to manufacture in MEMS technology. The hybrid kinematic structure contains three single-loop submechanisms connected in parallel to the moving platform. The solutions of the inverse and direct kinematics problems are presented

A new configuration of a six degrees-of-freedom parallel robot for MEMS fabrication

This paper deals with the difficulties that arise in the realization of micro-mechanisms by MEMS fabrication technique e.g.: fabrication of joints and actuators, joints clearance, lifting the structure from the 2D silicon wafer plane. It then introduces a new structure of a six degrees-of-freedom parallel robot that is suitable for MEMS fabrication. The robot consists of linear actuators located at the base and only revolute joints, both of which are easier to manufacture in MEMS technology. The hybrid kinematic structure contains three single loop sub-mechanisms connected in parallel to the moving platform, and the solution of its inverse kinematics which yields 4,096 solutions is presented.

Topological and Kinematic Singularities for a Class of Parallel Mechanisms

We study singularities for a parallel mechanism with a planar moving platform in ℝ 𝑑 ( 𝑑 = 2 , 3 ) , with joints which are universal, spherical (spatial case), or rotational (planar case). For such mechanisms, we give a necessary condition for a topological singularity to occur, and describe the corresponding kinematic singularity. An example is provided.

Kinematic Structure of a Parallel Robot for MEMS Fabrication

This investigation proposes a parallel robot structure that can be realized by MEMS technology. The robot consists of linear actuators located at the base and revolute joints only, thus making fabrication using silicon etching technology easier. The kinematic structure contains three single loop sub-mechanisms connected in parallel to the moving platform, enabling generation of three or six degrees-of-freedom mechanisms. The forward and inverse kinematics solutions are presented.