In this paper, a simple and convenient method – Recursive Matrix method – is proposed for kinematic and dynamic analysis of all types of complex manipulators. After addressing the principle of the method, an example – a 3-DOF parallel manipulator with prismatic actuators – is demonstrated for the efficiency of the method in solving kinematic and dynamic problems of complex manipulators. With the inverse kinematic solutions, the inverse dynamic problem is solved with the virtual powers method. Matrix relations and graphs of the acting forces and powers for all actuators are analysis and determined. It is shown that the proposed method is an effective mean for kinematic and dynamic modelling of parallel mechanisms.

A computational method for the steady 2-D flow in axially symmetrical rocket nozzles with a given profile is developed, in order to determine the Maximum thrust contour of rocket engine nozzles with large expansion ratio. The optimized nozzles proved a more than 10% increase in the integral specific impulse recorded during the variable altitude atmospheric flight of rocket vehicles. The method is well suited for application in the design of the optimum contour for axially-symmetric nozzles for atmospheric rocket ascent, specifically for aerospike type nozzles, as for other similar industrial applications in gas and steam turbine technology.

The constraints during the atmospheric ascent of the small NERVA rocket launcher are investigated, especially in regard to the limited flight envelope and mass optimization requirements. The usual flight ascent optimization faces in this case additional constraints, which must be solved with minimum losses of mass efficiency of the vehicle. A methodology of investigating the best ascent control laws is presented with emphasize on the second stage of the vehicle, regarding both the gas-dynamic controller system of the control unit and the accuracy of the inertial sensors of the self-guidance onboard system. The methodology is also focused on accommodating the high orbital insertion requirements of the gravity turn trajectory with a low-cost, highly secure flight controller system. Minimum technological modifications of the existing rocket propulsion system of the second stage are considered, which is a typical liquid propellant stage with aerodynamic and gas-dynamic attitude controls. Possible technological solutions are analyzed and compared regarding the accessibility of the ascent trajectories and optimal constrained solutions to the safety problem. The constraints are of safety, technological and international nature.

No abstract