Deutsche Aerospace Ag

Messerschmitt-bolkow-blohm Gesellschaft MIT Beschrankter Haftung

Messerschmitt-bolkow-blohm Gmbh

Helmut Bittner

Michael Surauer

Horst-Dieter Fischer

Walter Fichter

Eveline Gottzein

Ernst Bruderle

Francois Porte

Method of adjusting the position of satellites by means of solar

Process and a device for controlling the attitude of a three-axis

Measuring arrangement useful for controlling the attitude of a

Three-axis stabilized, earth-oriented satellite and a corresponding sun

A digital modulation process and apparatus for converting an input signal comprising a time variable series of sampling values, each of which sampling values remains constant within a fixed sampling period, into output signals representing a sequence of positive and/or negative pulses having a constant amplitude and a variable pulse width and frequency. The input signal and modulator parameters are supplied to a data processor. In order to reduce computing expenditures and at the same time achieve an increase in precision, by means of the computing system, the switch-on and switch-off points in time t.sub.se, t.sub.sa of the pulses as well as their operational signs are computed in one operation directly for each sampling period .DELTA.t.sub.k.

Process and a system for digital modulation

Attitude control process and device for a spacecraft to be rotated

Apparatus for controlling the attitude of and stabilizing an elastic body

A nonlinear frequency domain filter serving for the suppression of unwanted signals which are superposed on a wanted signal variable in a given frequency range. The frequency domain filter comprises linear transmission members and a dead-zone member. With the filter, the zero point of the dead-zone member, to which the input signal to be filtered is supplied, follows proportionally the output signal of a pass-band filter connected in parallel with the dead-zone member. Further, the output signal of the pass-band filter is added to the output signal of the dead-zone member.

Adaptive nonlinear frequency domain filter with low phase loss

Adaptive control system of high accuracy and low corrective energy

An arrangement for the attitude stabilization of flexible vehicles, such as ircraft and spacecraft. Such vehicles, due to their lightweight construction and/or large spatial extension or high degree of slenderness, have structurally weakly-dampened bending vibrations and/or torsional vibrations. For generating the forces and moments required for stabilizing such vehicle, discontinuously operating units are used. In one embodiment, for each vehicle axis, an observer or Kalman filter is employed for obtaining estimated values of the state variables of the vehicle system to be controlled. The observer has a first transfer function of at most third order. A state controller device is responsive to the observer for controlling the state variables. A modulator network is responsive to the state controller device wherein the modulator network has a relay characteristic. In this embodiment, a feedback path is arranged from the output of the modulator network to the observer which eliminates the need for a special modulator network having a second transfer function and also eliminates internal modulator feedback. In another form of the invention, the feedback is arranged from the input of the modulator to the observer and a low pass filter is included between the state controller device and the modulator network. The filter has either at least two low pass filter sections of first order or a single low pass filter section of at least second order. The break-point frequencies of the filter section or sections lies between the natural frequency of the rigid body and the lower structural resident frequency of the respective vehicle axis. Equivalent circuits are disclosed for replacing the observer and state controller device as described above. Adaptive techniques as well as digital realizations of the various embodiments are also disclosed.

Arrangement for the attitude stabilization of flexible vehicles with

A controller for the attitude stabilization of a satellite. The controller odifies the action of a first control circuit by responding to the signals of attitude .phi. and angular velocity of attitude .phi. developed by the first control circuit. A second control circuit includes a comparator, two Schmitt trigger circuits, two AND elements and two OR elements. Signals from the AND elements and uncorrected thrust nozzle control signals from the first control circuit are supplied to the OR elements. The output of the OR elements control the thrust nozzles of the satellite.

Controller for the attitude stabilization of a satellite

Growing community of inventors

Munich, Germany

Helmut Bittner