Experimental Study of Upsetting and Die Forging with Controlled Impact
The results from experimental research of deformation by upsetting and die forging of lead specimens wit controlled impact are presented. Laboratory setup for conducting the investigations, which uses cold rocket engine operated with compressed air, is described. The results show that when using controlled impact is achieving greater plastic deformation and consumes less impact energy than at ordinary impact deformation process. Keywords—Rocket Engine, Forging Hammer, Sticking Impact, Plastic Deformation.
KINEMATIC INVARIANTS WITH INFINITESIMALLY CLOSE POSITIONS OF MECHANISMS WITH TWO DEGREES OF FREEDOM
The last 2-3 decades are characterized by the widespread use of robots in the micro world for molecular and nano technological operations. There is a dynamic development in the area of micro and nano actuators. Macro and micro movements are consecutive and to a great extent independent of each other. The structures of the manipulation mechanisms (??) change according to the activation of macro motors or micro actuators. In both cases micro operations are performed by short-range movements. In this sense, the synthesis of ?? through the methods of infinitesimally close positions (ICP) is particularly appropriate. With the mechanisms having two degrees of freedom (DoF) two substantially different problems for the synthesis with ICP can be formulated: a direct problem – one for a given configuration of the mechanism and a given transmission ratio of the velocities at the two inputs where the point of Boll is to be found, and a reverse problem where with a given point of Boll and the normal to its trajectory the kinematic parameters of the mechanism are sought. In the present paper a methodology was created for the synthesis with ICP, adopted for five-link mechanisms with two DoF. The said methodology may also be used with slight amendments to it for the synthesis of mechanisms with open kinematic chains. Actually, ICP are the end sections of the trajectory. They can be used with precise finishing operations. The input velocities may be constant, whereby the impact of the inertia forces, and of the deformations, respectively, becomes insignificant.
Development of mobile versatile nanohandling microrobots: design, driving principles, haptic control
Special micromanipulators are needed to manipulate very small objects. Most micromanipulators are specialized to perform a task they are designed for, but are too inflexible to adapt to other problems. Therefore, flexible newly developed mobile microrobots are presented with precision in the sub-micrometer range while offering a macroscopic workspace. The main parts of each mobile microrobot, the mobile platform, the manipulator and end effectors, are explained in detail, with some experimental data given. The new driving principle of the mobile platform allows high resolution, low energy consumption, which makes an on-board power supply feasible and a maximum velocity of several mm/s. Useful human interfaces are needed for a successful teleoperation. The most important interface next to the vision feedback is a haptic interface. The paper presents a newly developed haptic interface for a micromanipulation station. The mechanical design and the design of the control system of the haptic interface are discussed in details. The control architecture of the micromanipulation station and the integration of the haptic device into the micromanipulation station are presented.