Umit Poyraz Roketsan INC., Ankara, Turkey Abstract The precise control of gas generator pressure is important to obtain variable thrust in ducted rockets. A delay resistant closed loop reference model adaptive control is proposed in this paper to address this problem. The proposed controller combines delay compensation and adaptation with improved transient response. The controller is successfu...

An effective method for the design of fuel-optimal transfers in twoand threebody dynamics is presented. The optimal control problem is formulated using calculus of variation and primer vector theory. This leads to a multi-point boundary value problem (MPBVP), characterized by complex inner constraints and a discontinuous thrust profile. The first issue is addressed by embedding the MPBVP in a p...

This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The t...

Due to their size, small rotorcraft are vulnerable to external flow disturbances that are challenging to flight stability and control. This paper describes preliminary results from using onboard flow measurements to augment inertial sensors for attitude control. We derive a dynamic model that captures the aerodynamic effects of wind on a single degree-of-freedom tandem-rotor test stand. A pair ...

A computational study of helicopter vibration and rotor shaft power reduction is conducted using activelycontrolled trailing-edge flaps (ACFs), implemented in both single and dual flap configurations. Simultaneous vibration reduction and performance enhancement is demonstrated under level flight condition at high advance ratios, where dynamic stall effects are significant. Power reduction is ac...

Optimal space trajectory problems and the necessaly and sufficient conditions that define their solutions are stated most compactly in terms of position and velocity vectors. To obtain analytical or numerical solutions, however, the problems are expressed using a particular set of coordinates. Each set of coordinates has advantages and disadvantages depending on the application. Thus, it may be...

A high-precision variable-thrust control method based on real-time measurement of pintle displacement and closed-loop feedback is proposed to solve the technical problems deep throttling regulation liquid rocket engines (LRE). By optimizing system structure parameters, with high precision a fast response under wide range variable thrust can be realized, thus large-range, fast-response, chamber ...

The inverted-pendulum method of thrust measurement for high-power electric thrusters is described analytically and experimentally. Two sources of uncertainty in the thrust measurements are investigated: those due to changes in the sensitivity of the inverted pendulum and those due to tare forces resulting from thermal stresses and electromagnetic forces acting on the flexural elements. An ideal...

The optimal design of the thrust vector control system solid rocket motors (SRMs) is discussed. injection a supersonic underexpanded gas jet into diverging part engine nozzle considered, and multiparameter optimization geometric shape parameters flow developed. turbulent viscous compressible in main simulated with Reynolds-averaged Navier–Stokes (RANS) equations shear stress transport (SST) tur...

In order to achieve powered autonomous running robots it is essential to develop efficient actuator systems, especially in the case of the actuatorsfor generating the radial thrust in the legs. In addition, the control of the radial thrust of the legs can be a simple, effective method for stabilizing the body pitch in a running gait. This paper presents the mechanical systems, the models and co...