Symmetry preserving nonlinear observer for attitude estimation with magnetometer only.

This paper addresses designing a nonlinear symmetry observer for nano-satellite attitude determination with only Three-Axis Magnetometer (TAM). Hence, two nested filters are delineated to compensate for the lack of data and to solve the observability problem. In the first filter, the magnetic field derivative is estimated by the extended Kalman filter. Subsequently, the magnetic field and its derivative are applied in the second filter. The proposed methodology relies on invariant observers under the action of a Lie group to estimate the attitude and angular velocity simultaneously. Later, the invariant error dynamic equations are utilized in designing the observer. Consequently, the desired performance of this proposed observer tuned by periodic Riccati differential equation is validated through both simulation and exponential stability proof.

Computer implementation of a new therapeutic model for GBM tumor.

Modeling the tumor behavior in the host organ as function of time and radiation dose has been a major study in the previous decades. Here the effort in estimation of cancerous and normal cell proliferation and growth in glioblastoma multiform (GBM) tumor is presented. This paper introduces a new mathematical model in the form of differential equation of tumor growth. The model contains dose delivery amount in the treatment scheme as an input term. It also can be utilized to optimize the treatment process in order to increase the patient survival period. Gene expression programming (GEP) as a new concept is used for estimating this model. The LQ model has also been applied to GEP as an initial value, causing acceleration and improvement of the algorithm estimation. The model shows the number of the tumor and normal brain cells during the treatment process using the status of normal and cancerous cells in the initiation of treatment, the timing and amount of dose delivery to the patient, and a coefficient that describes the brain condition. A critical level is defined for normal cell when the patient's death occurs. In the end the model has been verified by clinical data obtained from previous accepted formulae and some of our experimental resources. The proposed model helps to predict tumor growth during treatment process in which further treatment processes can be controlled.

Stabilization loop of a two axes gimbal system using self-tuning PID type fuzzy controller.

The application of inertial stabilization system is to stabilize the sensor's line of sight toward a target by isolating the sensor from the disturbances induced by the operating environment. The aim of this paper is to present two axes gimbal system. The gimbals torque relationships are derived using Lagrange equation considering the base angular motion and dynamic mass unbalance. The stabilization loops are constructed with cross coupling unit utilizing proposed fuzzy PID type controller. The overall control system is simulated and validated using MATLAB. Then, the performance of proposed controller is evaluated comparing with conventional PI controller in terms of transient response analysis and quantitative study of error analysis. The simulation results obtained in different conditions prove the efficiency of the proposed fuzzy controller which offers a better response than the classical one, and improves further the transient and steady-state performance.