In this paper, a new technique for fine tuning of spacecraft autopilots based on pulse-width pulse-frequency (PWPF) modulators is presented. PWPF is one of the most commonly used approaches to control signal modulation. Its main application is found in spacecraft controllers to produce discontinuous on-off control signals for two situational actuators. The main reasons for the popularity of this method are the reduced energy consumption and the quasi linear operation with high degrees of freedom in adjustment. But, due to multiplicity and nonlinear relationship between parameters, fine tuning of PWPF is known to be an engineering problem. Similar complexity is observable in adjusting the incorporated controller parameters. These involvements regarding the industrial and academic background of PWPF are not properly explored. The paper shows how particle swarm optimization (PSO) can be invoked to set both controller and PWPF parameters. Several spacecraft autopilots have been designed to show effectiveness of the proposed method.

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Tuning of Pulse-Width Pulse-Frequency Modulator using PSO: An Engineering Approach to Spacecraft Attitude Controller Design

A second generation sun sensor for sounding rocket applications

High performance reaction pointing control systems for sounding rockets, using proportional control of differential thrust and adaptive control of thrust magnitude

A New Reaction Control Approach for Sounding Rockets

A high altitude parachute suspended solar pointing control system has been developed and flight tested for use in the altitude range of 30 to 70 kilometers. This development provides an opportunity for extended solar observations at altitudes higher than that attainable by helium balloons. The new system utilizes the NASA high altitude cross parachute to slow the descent of a rocket launched payload allowing observations in the region of interest. Solar pointing is established by using solar sensors in conjunction with a servo controlled platform and cold gas thrusters for payload roll control. The inherent spin of the cross parachute is decoupled by a swivel joint attached to the parachute suspension lines. This paper describes the design, test and flight performance of the new system.

Parachute suspended solar pointing control system

A high altitude parachute suspended solar pointing control system has been developed and flight tested for use in the altitude range of 30 to 70 kilometers. This development provides an opportunity for extended solar observations at altitudes h igher than that attainable by helium balloons. The new system utilizes the NASA high altitude cross parachute to slow the descent o f a rocket launched payload allowing observations in the region of interest. Solar pointing is established by using solar sensors in conjunction with a servo controlled platform and cold gas thrusters for payload roll control. The inherent spin of the cross parachute is decoupled by a swivel joint attached to the parachute s uspension lines. This paper describes the design, test and flight performance of the new system.

Q. M. Hansen

Papers

A gyroless sounding rocket control system with sub-arc-second pointing stability

A Gyroless Control System for Sub-Arc Second Solar Pointing of a Sounding Rocket Payload