Controlling the degree of observability in GPS/INS integration land-vehicle navigation based on extended Kalman filter

Experimental setup implements the concept of degree of observability (DoO) adequate a land-vehicle navigation application with noised inertial measurement unit (IMU) and global positioning system (GPS) sensors based on a loosely coupled approach. The navigation systems such as IMU-GPS require extensive evaluations of nonlinear equations as used in an extended Kalman filter (EKF). According to DoO and during our test, we have implemented a method for measuring the DoO of all states continuously. Where, the results showed that applying the fusion IMU-GPS system based on EKF be enhanced the DoO measure. The real dataset consists of outputs a high sampling rate for IMU sensor at each (0.01s) and GPS receiver at each (1s). In addition, an aloft category IMU was put together with differential GPS (DGPS) information to produce a real trajectory. GPS has acceptable long-term accuracy, it is used to update the position and velocity in IMU outputs before processing in the EKF algorithm. The implementation consists of three main algorithms: Strapdown (dead reckoning DR), DoO and EKF algorithms. The results are shown, implementation of both approaches based on EKF and the concept of DoO in GPS/INS integrated systems are sufficient robustness to use with low-cost sensors

Controlling the degree of observability in GPS/INS integration land-vehicle navigation based on extended kalman filter

Experimental setup implements the concept of degree of observability (DoO) adequate a land-vehicle navigation application with noised inertial measurement unit (IMU) and global positioning system (GPS) sensors based on a loosely coupled approach. The navigation systems such as IMU-GPS require extensive evaluations of nonlinear equations as used in an extended Kalman filter (EKF). According to DoO and during our test, we have implemented a method for measuring the DoO of all states continuously. Where, the results showed that applying the fusion IMU-GPS system based on EKF be enhanced the DoO measure. The real dataset consists of outputs a high sampling rate for IMU sensor at each (0.01s) and GPS receiver at each (1s). In addition, an aloft category IMU was put together with differential GPS (DGPS) information to produce a real trajectory. GPS has acceptable long-term accuracy, it is used to update the position and velocity in IMU outputs before processing in the EKF algorithm. The implementation consists of three main algorithms: Strapdown (dead reckoning DR), DoO and EKF algorithms. The results are shown, implementation of both approaches based on EKF and the concept of DoO in GPS/INS integrated systems are sufficient robustness to use with low-cost sensors

Structural heterogeneities in starch hydrogels

Hydrogels have a complex, heterogeneous structure and organisation, making them promising candidates for advanced structural and cosmetics applications. Starch is an attractive material for producing hydrogels due to its low cost and biocompatibility, but the structural dynamics of polymer chains within starch hydrogels are not well understood, limiting their development and utilisation. We employed a range of NMR methodologies (CPSP/MAS, HR-MAS, HPDEC and WPT-CP) to probe the molecular mobility and water dynamics within starch hydrogels featuring a wide range of physical properties. The insights from these methods were related to bulk rheological, thermal (DSC) and crystalline (PXRD) properties. We have reported for the first time the presence of highly dynamic starch chains, behaving as solvated moieties existing in the liquid component of hydrogel systems. We have correlated the chains’ degree of structural mobility with macroscopic properties of the bulk systems, providing new insights into the structure-function relationships governing hydrogel assemblies

Adsorption of polyampholyte copolymers at the solid/liquid interface: the influence of pH and salt on the adsorption behaviour

Polyampholytes are macromolecules that contain oppositely charged groups. We have studied the adsorption of the polyampholyte diblock copolymer poly(methacrylic acid)-block-poly((dimethylamino)ethyl methacrylate), PMAA-b-PDMAEMA, on oxidized silicon surfaces. The amount of polymer adsorbed from aqueous solution of different pH and salt concentration was measured by ellipsometry. The influence of the added salts NaCl, Na2SO4 and CaCl2 was determined. In every case adsorption took place, although the polyampholyte and the substrate exhibit the same sign of net charge. For all types of salt, the adsorbed amount shows two maxima close to the isoelectric point (IEP) of the polymer as a function of pH. Directly at the IEP of the polyampholyte, no adsorption was found. The measured dependences can be explained by the adsorption of one or the other of the two blocks depending on acidity and ionic strength. Furthermore, the lateral structure of the dried films was investigated by scanning force microscopy (SFM)

Block balance in hydrogenated polybutadiene-b-polymethylmethacrylate diblock copolymer for efficient interfacial activity in low-density polyethylene/polymethylmethacrylate blend: Phase morphology development

The objective of the present study was to determine the best molecular balance between the two hydrogenated polybutadiene (HPB) and polymethylmethacrylate (PMMA) blocks that promotes an HPB-b-PMMA diblock copolymer with efficient compatibilization activity in a low-density polyethylene (LDPE)/PMMA immiscible blend. The model blend selected, LDPE/PMMA, is "more immiscible" than the LDPE/polystyrene pair largely reported in open literature. The blends having a composition of 80LDPE/20PMMA exhibit a droplet-in-matrix phase morphology whereas in 20LDPE/ 80PMMA a co-continuous phase morphology was developed. In the droplet-in-matrix phase morphology, the emulsifying efficiency of the copolymer was evaluated based on the maximum reduction of the PMMA droplet size it is able to promote. Whereas, in the co-continuous phase morphology, the copolymer was evaluated based on its ability to stabilize the maximum phase co-continuity. The sequences of the best emulsifying copolymer revealed are not symmetrical. An HPB-b-PMMA where the ratio of molar mass of the blocks, M-n (HPB)/M-n (PMMA), is within 1.8-1.95 exhibits a much better interfacial activity in LDPE/PMMA blends than a copolymer of much lower ratio (longer PMMA block). This is ascribed to the much higher interactions (cohesive energy density) encountered in PMMA (PMMA of the copolymer and PMMA phase of the blend) compared with the LDPE side (HPB of the copolymer and LDPE phase of the blend). (c) 2005 Wiley Periodicals, Inc

Effect of block copolymers of various molecular architecture on the phase morphology and tensile properties of LDPE rich (LDPE/PS) blends

The emulsification efficiency of three different block copolymers consisting of hydrogenated polybutadiene (HPB) and polystyrene (PS), i.e. a pure diblock , a tapered diblock and a triblock copolymer has been compared in low density polyethylene/polystyrene (LDPE/PS) blends rich in polyethylene. The comparison relies upon the ability of these potential interfacial agents to stabilize fine phase dispersion and to promote good interfacial adhesion. Based on the phase morphology, the ultimate tensile properties and the dynamic viscosity of the modified blends, the tapered diblock copolymer is clearly the most efficient emulsifier. For instance a plateau is observed in the property-copolymer content dependence when 2 wt% tapered diblock are used compared to ca. 5 wt% in case of the pure diblock. In contrast, no plateau is observed when the triblock copolymer is used. This is assumed to result from a less quantitative localization of these two copolymers i.e. the pue diblock or the triblock at the LDPE/PS interface