Application of predictive control for manipulator mounted on a satellite

Specific conditions of on-orbit environment are taken into account in the design of all devices intended to be used in space. Despite this fact malfunctions of satellites occur and sometimes lead to shortening of the satellite operational lifetime. It is considered to use unmanned servicing satellite, that could perform repairs of other satellites. Such satellites equipped with a manipulator, could be used to capture and remove from orbit large space debris. The critical part of planned missions is the capture manoeuvre. In this paper a concept of the control system for the manipulator mounted on the satellite is presented. This control system is composed of the trajectory planning module and model predictive controller (the latter is responsible for ensuring precise realization of the planned trajectory). Numerical simulations performed for the simplified planar case with a 2 DoF manipulator show that the results obtained with the predictive control are better than the results obtained with adaptive control method

Manipulator trajectories during orbital servicing mission: numerical simulations and experiments on microgravity simulator

It is considered to use a manipulator-equipped satellite for performing On-Orbit Servicing (OOS) or Active Debris Removal (ADR) missions. In this paper, several possible approaches are reviewed for end-effector (EE) trajectory planning in the Cartesian space, such as application of the Bézier curves for singularity avoidance and method for trajectory optimization. The results of numerical simulations for a satellite equipped with a 7 degree-of-freedom (DoF) manipulator and results of experiments performed on a planar air-bearing microgravity simulator for a simplified two-dimensional (2D) case with a 2-DoF manipulator are presented. Differences between the free-floating case and the case where Attitude and Orbit Control Systems (AOCS) keep constant position and orientation of the satellite are also shown

Projekt i budowa dwóch modeli laboratoryjnych manipulatorów jako kluczowy element stanowiska testowego dedykowanego robotom kosmicznym

The process of designing control systems for devices operating in microgravity, on-orbit environment, requires testing to verify the effectiveness and characteristics of the algorithms. The key issue is to design a relevant environment in terrestrial conditions that affects both the linear and angular three-dimensional motion of a rigid body. This paper contains a description of the mechanical aspects of two test beds used to evaluate control algorithms planned for use in a space manipulator. Two solutions are presented: (i) a planar manipulator with a free base placed on an air-bearing table; and (ii) a test bed with a 7-DOF manipulator fixed through a force-torque measurement system to the base.Podczas procesu projektowania układów sterowania robotów pracujących w warunkach mikrograwitacji niezbędna jest możliwość przeprowadzenia ich walidacji w relewantnym środowisku. Kluczowym problemem jest budowa stanowisk testowych pozwalających na analizowanie ruchu manipulatora umieszczonego na swobodnej bazie, której ruch odbywa się w trzech wymiarach. Artykuł zawiera opis dwóch stanowisk testowych wykorzystywanych do analizy działania algorytmów sterowania w zrobotyzowanych systemach satelitarnych. W artykule opisano symulator warunków mikrograwitacji w postaci manipulatora płaskiego ze swobodną bazą umieszczoną na łożyskach powietrznych oraz stanowisko testowe wyposażone w manipulator o 7 stopniach swobody z utwierdzoną bazą pozwalającą na pomiar 3 składowych siły i momentu siły

Control System for Free-Floating Space Manipulator Based on Nonlinear Model Predictive Control (NMPC)

Manipulator mounted on an unmanned satellite could be used for performing orbital capture maneuver in order to repair satellites or remove space debris from orbit. Use of manipulators for such purposes presents unique challenges, as high level of autonomy is required and the motion of the manipulator influences the position and orientation of the manipulator-equipped satellite. This paper presents a new control system that consists of two modules: trajectory planning module (based on trajectory optimization algorithm) and Model Predictive Controller. Both mod

Nonlinear model predictive control (NMPC) for free-floating space manipulator

Manipulators are widely used in orbital operations, for example, Mobile Servicing System on the International Space Station and Shuttle Remote Manipulator System are used for several years. Such manipulators are operated by astronauts and mounted on large platforms, thus influence of manipulator motion on the state of the platform is not significant. Application of manipulators for capture maneuvers in unmanned On-Orbit Servicing or Active Debris Removal missions requires reliable control algorithms that take into account the free-floating nature of the manipulator-equipped spacecraft. In this paper the possibility of using Nonlinear Model Predictive Control (NMPC) for controlling such manipulators is presented. Numerical simulations for a simplified planar case show effectiveness of the proposed controller

Grzybicze powikłania zakażeń układu zastawkowego u dzieci z wodogłowiem wrodzonym

Mycotic complications of shunt infection in children with primary hydrocephalus. Recently, the incidence of fungal infections in children, including cbildren with shunt-dependent hydrocephalus, has increased. The analysis comprised 8 cbildren treated in the III Clinic of Pediatrics of ICZMP during the period of 12 months (12% of all infectious complications of the shunt system). The clinical picture of fungal infection included Symptoms of shunt dysfunction: febrile conditions, vomiting, distress and loss of appetite. The most common pathogens isolated from the cerebro-spinal fluid were fungi from the Candida species. Mean value of pleocytosis in the cerebro-spinal fluid was 812 cell/μ, and mean protein concentration was 311 mg/dl. Treatment consisted of monotherapy with Dillucan, monotherapy with Ancotil or combined treatment with Ancotil and Amphotericine B. The drugs were administered intravenously and intraventricolarly after removal of the shunt and application of external drainage. Sterility of cerebro-spinal fluid was obtained in the shortest time with the use of Ancotil. Propbylactic application of antifungal drugs decreases the frequency of infections in children with shunt-dependent hydrocepbalus

Grzybicze powiklania zakazen ukladu zastawkowego u dzieci z wodoglowiem wrodzonym

Mycotic complications of shunt infection in children with primary hydrocephalus. Recently, the incidence of fungal infections in children, including cbildren with shunt-dependent hydrocephalus, has increased. The analysis comprised 8 cbildren treated in the III Clinic of Pediatrics of ICZMP during the period of 12 months (12% of all infectious complications of the shunt system). The clinical picture of fungal infection included Symptoms of shunt dysfunction: febrile conditions, vomiting, distress and loss of appetite. The most common pathogens isolated from the cerebro-spinal fluid were fungi from the Candida species. Mean value of pleocytosis in the cerebro-spinal fluid was 812 cell/μ, and mean protein concentration was 311 mg/dl. Treatment consisted of monotherapy with Dillucan, monotherapy with Ancotil or combined treatment with Ancotil and Amphotericine B. The drugs were administered intravenously and intraventricolarly after removal of the shunt and application of external drainage. Sterility of cerebro-spinal fluid was obtained in the shortest time with the use of Ancotil. Propbylactic application of antifungal drugs decreases the frequency of infections in children with shunt-dependent hydrocepbalus

Moon's sub-surface layers exploration by using ''KRET'' penetrator

Przyrządy wykorzystywane na lądownikach księżycowych muszą charakteryzować się niewielką masą oraz niewielkim zużyciem energii elektrycznej. Jednym z rozwiązań pozwalających na spełnienie obu tych kryteriów w przypadku instrumentów przeznaczonych do badania warstw podpowierzchniowych są penetratory. W niniejszym artykule opisano opracowany przez CBK PAN penetrator KRET, który jest unikalną konstrukcją inżynierską przeznaczoną do badania ciał Układu Słonecznego.Devices utilized in Moon's landing modules have to exhibit low energy consumption as well as low mass. One of the solutions fulfilling both, energy consumption and low mass is the penetrator. This article describes the penetrator KRET created by CBK PAN (Solar Physics Division - Polish Academy of Sciences). Penetrator KRET is a unique engineered construction designed for the Solar System studies