ABSTRACT
This work presents an algorithm to determine instantaneous orientation of an object in 3D space. The orientation was determined by using a Direction Cosine Matrix (DCM), performed by the combination of three consecutive rotations, around each to the main axes of the evaluated system, using quaternions. An inertial measurement unit (IMU), consisting of 3 axes gyroscope and 3 axes accelerometer was used in order to establish 2 coordinate systems; The first one describes object movement, by using gyroscope as a main source of information, relating the angular rate of change along time. The second defines a coordinate reference system, relating the acceleration of gravity to an inertial direction vector. A proportional integral (PI) feedback controller was used, which includes sensors information, eliminating offset, cancelling drift and improving the accuracy of the orientation. The proposed algorithm can be used for assessing both the position and orientation of the body segments which is very important in orthopedic, traumatology and rheumatology important for diagnosis, prognostic, therapeutic, research and as well as the design and fabrication of measuring devices used in surgical instrumentation, prostheses and ortheses. It is important to note that the developed system opens the opportunities to be implemented on ambulatory joint evaluation through a wearable system, due to the dimensions and requirements of the sensors.
El presente trabajo presenta un algoritmo para determinar la orientación instantánea de un objeto en el espacio 3D. La orientación fue determinada utilizando una matriz de cosenos directores (DCM) conformada por la combinación de 3 rotaciones consecutivas alrededor de cada uno de los ejes del sistema evaluado, utilizando cuaterniones. Una unidad inercial de medida (IMU) compuesta por un giroscopio de 3 ejes y un acelerómetro de 3 ejes fue utilizada con el objetivo de establecer 2 sistemas coordenados; Un sistema coordenado describiendo el movimiento del objeto, utilizando al giroscopio como fuente principal de información, estableciendo la relación de cambio con respecto al tiempo. Un sistema coordenado de referencia, relacionando la aceleración gravitacional a un vector inercial. Un control por retroalimentación proporcional integral (PI) fue utilizado con el objetivo de combinar la información de los sensores, eliminando las desviaciones por offset y deriva, mejorando la precisión en la orientación. Dadas sus características, el algoritmo propuesto permite su utilización en la evaluación de la posición y la orientación de los segmentos corporales, siendo de suma importancia en ortopedia, traumatología y reumatología para la determinación de diagnósticos, pronósticos terapéuticos e investigación así como el diseño y fabricación de dispositivos de medición, instrumentación quirúrgica, prótesis y ortesis. Cabe destacar que el sistema desarrollado abre oportunidades de ser implementado en el diseño de sistemas ambulatorios de evaluación de las articulaciones, mediante el uso de elementos transportables dadas las reducidas dimensiones y limitaciones de los sensores empleados.
ABSTRACT
AIM: The method of the double qualitative similarities and the double quantitative similarities was carried out for the evaluation of the chromatographic fingerprints and applied to HPLC fingerprints of Rhizoma anemarrhenae. METHODS: The chromatographic fingerprints were obtained by injecting 5 ?L of the sample solution each time on a CenturySIL C_(18) BDS column(20 cm?4.6 mm,5 ?m) with the gradient elution solvent system composed of 1% acetic acid-water and 1% acetic acid-acetonitrile.The column temperature was maintained at(30?0.15) ℃ and the detection wavelength was set at 265 nm.The chromatographic fingerprints were evaluated by the normalized similarity S_F and normalizing similarity S′_F and the projecting similarity C% and quautitative similarity P%, changes in characteristics were investigated in the cases of big peaks-free and small peaks-free respectively. RESULTS: 21 co-possessing peaks were selected as the fingerprint peaks of Rhizoma anernarrhenae by choosing rutin peak as the reference peak.S_F could clearly reflect the chemical constituent distribution,and C% could reflect the total contents of the sample,but both of them were seriously influenced by the big peaks and could not reflect the missing of small peaks.S′_F and P% were equivalent weight to all fingerprint peaks,and they could reflect sensitively the small peaks drop-out. CONCLUSION: The double qualitative similarities and the double quantitative similarities are composed of S_F,S′_F,C% and P%,so the changes or lacks of both big peaks and small peaks can be punctually simultaneously monitored to be a novel method for evaluating fingerprints.The HPLC fingerprints can be useful in the quality control of Rhizoma anemarrhenae.