Ridanto Eko Poetro

The saturated quaternion control law with application for spacecraft formation flying

Rotation matrix parameterization using unit quaternion can represent attitude globally. However, it is not unique and may generates the unwinding phenomenon, besides the issue on the globally asymptotically stability guarantee. This paper proposes a piecewise-continuous scheme of quaternion-based control law that employs a saturation element such that would avoid the unwinding phenomenon. This paper also proposes a consensus control scheme based on the saturated quaternion control law that would show the property of the unwinding phenomenon avoidance and the corresponding graph only need to have a directed spanning tree.

Evaluation of attitude dynamic module on LAPAN-ITB micro-satellite simulator

A satellite simulator is needed in the development of satellite system and subsystems development, for simulating the conditions of the satellite operation. It is also used in the training of satellite operators. Software-based satellite simulator has been known to reduce the risk and cost of satellite development, mainly since the design validation can be done without having to develop costly hardware. LAPAN-ITB microsatellite simulator is developed mainly using MATLAB software and C programming language. The paper discuss about the evaluation of the attitude dynamics module of the simulator. The evaluation is performed by running several satellite attitude dynamic cases and observing the outputs for physical validity. The results show that the attitude dynamics module has been able to properly simulate the attitude of satellite with 3 orthogonal reaction wheels.

Quaternion-Based attitude control system design of single and cooperative spacecrafts: boundedness of solution approach

It is well known that single equilibrium orientation point in matrix rotation is represented by two equilibrium points in quaternion. This fact would imply nonefficient control effort as well as problem in guaranteeing stability of the two equilibrium points in quaternion. This paper presents a solution to design quaternion-based spacecraft attitude control system whose saturation element is in its control law such that those problems are overcome. The proposed feature of methodology is the consideration on boundedness of solution in the control system design even in the presence of unknown external disturbance. The same methodology is also used to design cooperative spacecrafts attitude control system. Through the proposed method, the most relaxed information-state topology requirement is obtained, that is, the directed graph that contains a directed spanning tree. Some numerical simulations demonstrate effectiveness of the proposed feature of methodology.

Multi-objectives optimization of earth observation micro-satellite design using particle swarm

The objective of the research is to computationally get the best satellite system design, according to the performance criteria defined. The satellite type used in this research is the one that weight no more than 100 kg and dimension can be fitted into auxilary payload allocation in the Low-Earth-Orbit (LEO) launch vehicle. The satellite mission chosen in this research is Earth observation using 2 optical payloads of 4-band multispectral imager. The 2 performance criteria chosen are the image resolution and the image swath, which are trade-off of one another. The constrains on the design, in addition to the satellite launch envelope, is the downlink data rate. The aspects of subsystem design are assumed to be based on available technologies. The optimization is done using multi-objective particle swarm algorithm (MOPSO) scheme. The result obtained is the pareto front presenting choices for the designer on the satellite with optimal image resolution and swath, which then validated by comparing with manual calculation. The recomended parameter combinations are then used to calculate satellite system parameters.

The quaternion-based attitude control system with an augmented dynamic

Quaternion-based attitude determination system is considered since it can represent all physical attitudes, but not uniquely. An inappropriate quaternion-based control law would imply to a non-efficient control effort and difficulty in guaranteeing global stability. Many research efforts decide to add complexity in the controller by using jump-discontinuity function and/ or hybrid system. In contrast, this paper proposes a continuous quaternion-based attitude control system with an augmented dynamic that guaranteed to be able to regulate any physical state asymptotically. The effectiveness of the designed system is verified through simulations.

IiNUSAT-1: The 1 st Indonesian inter-university nano-satellite for research and education

Mastery of aerospace technology becomes very important for Indonesia. Due to the given the vast areas of Indonesia mostly in the form of marine waters.This condition has made a guarding and monitoring becomes easy. Therefore needed satellite technology that can be utilized to guard the interests of the territory of Indonesia. The success of developing IiNUSAT-1 on the one hand proves that the universities in Indonesia have competence in the field of nano-satellite development, on the other hand also shows that gotong-royong (working-together) in research-networks and technology will accelerate the research competence. In the first year of development IiNUSAT-1 produced a document Prelimidary Design Review, and a prototype of the nano-satellite. The result shows that the nano-satellite prototype has maximum transfer rate 115.2 kbps and every parameter is sampled every second. Having experience developing and operating the nano-satellite in the first year research project, it will trigger the research related to security and prosperity of the nation. The next version of the nano-satellite will be payloaded with sensors and instruments which can be utilized for national security and prosperity.