Development of transgenic sorghum for insect resistance against the spotted stem borer (Chilo partellus)

Transgenic sorghum plants expressing a synthetic cry1Ac gene from Bacillus thuringiensis (Bt) under the control of a wound-inducible promoter from the maize protease inhibitor gene (mpiC1) were produced via particle bombardment of shoot apices. Plants were regenerated from the transformed shoot apices via direct somatic embryogenesis with an intermittent three-step selection strategy using the herbicide Basta. Molecular characterisation based on polymerase chain reaction and Southern blot analysis revealed multiple insertions of the cry1Ac gene in five plants from three independent transformation events. Inheritance and expression of the Bt gene was confirmed in T1 plants. Enzyme-linked immunosorbant assay indicated that Cry1Ac protein accumulated at levels of 1–8 ng per gram of fresh tissue in leaves that were mechanically wounded. Transgenic sorghum plants were evaluated for resistance against the spotted stem borer (Chilo partellus Swinhoe) in insect bioassays, which indicated partial resistance to damage by the neonate larvae of the spotted stem borer. Reduction in leaf damage 5 days after infestation was up to 60%; larval mortality was 40%, with the surviving larvae showing a 36% reduction in weight over those fed on control plants. Despite the low levels of expression of Bt delta-endotoxin under the control of the wound-inducible promoter, the transgenic plants showed partial tolerance against first instar larvae of the spotted stem borer

Robust fixed order lateral H-2 controller for micro air vehicle

This paper presents a robust fixed order H-2 controller design using Strengthened discrete optimal projection equations, which approximate the first order necessary optimality condition. The novelty of this work is the application of the robust H-2 controller to a micro aerial vehicle named Sarika2 developed in house. The controller is designed in discrete domain for the lateral dynamics of Sarika2 in the presence of low frequency atmospheric turbulence (gust) and high frequency sensor noise. The design specification includes simultaneous stabilization, disturbance rejection and noise attenuation over the entire flight envelope of the vehicle. The resulting controller performance is comprehensively analyzed by means of simulation

Real-Time Fixed-Order Lateral H

This paper presents the design and development of a fixed low-order, robust H2 controller for a micro air vehicle (MAV) named Sarika-2. The controller synthesis uses strengthened discrete optimal projection equations and frequency-dependent performance index to achieve robust performance and stability. A single fixed gain low-order dynamic controller provides simultaneous stabilization, disturbance rejection, and sensor noise attenuation over the entire flight speed range of 16 m/sec to 26 m/sec. Comparative study indicates that the low-order H2-controller achieves robust performance levels similar to that of full order controller. Subsequently, the controller is implemented on a digital signal processor-based flight computer and is validated through the real time hardware in loop simulation. The responses obtained with hardware in loop simulation compares well with those obtained from the offline simulation

Robust estimation of linear velocity states of Micro Air Vehicle using Monocular

This paper introduces robust estimation of micro air vehicle's linear velocity from captured images using a monocular camera in GPS denied environment. Vehicle's velocity information can be extracted from matched feature points of consecutive images; however, robust techniques are required for reliable information as these estimations algorithms are prone to high image noise and unavailability of enough matched feature points. In this paper, the estimation technique is considered based on fast estimation method where the estimation error can be made arbitrary small using the high update gain and high bandwidth of low pass filter. The performance bound is only restricted by the computational resources of the hardware. The proposed scheme is built after modification of predictor equation in original fast estimation method which involves driving the predictor dynamics according to estimation error. The velocity states are obtained using the fundamental kinematics motion of world object in camera frame fixed to micro air vehicle. It is assumed that vertical height from the ground is available from other sensors and the object depth information is approximated using the flat earth model.The estimation is carried out in the realistic simulation environment by interfacing of a six-dof nonlinear model and virtual environment. Simulation results show the robustness of the proposed method. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved

Output Feedback-Based Discrete-Time Sliding-Mode Controller Design for Model Aircraft

Model aircraft provide a low-cost test bed for the design and validation of control algorithms. The control system should improve the transient response and have good disturbance-rejection properties. The stability derivatives of the aircraft vary due to in-flight velocity fluctuations and the controller should be invariant to such perturbations. Weight and power requirements of the aircraft payload restrict the number of onboard sensors and so a limited number of output measurements can be used for feedback

Autonomous Star Camera Calibration and Spacecraft Attitude Determination

This paper presents two methods of star camera calibration to determine camera calibrating parameters (like principal point, focal length etc) along with lens distortions (radial and decentering). First method works autonomously utilizing star coordinates in three consecutive image frames thus independent of star identification or biased attitude information. The parameters obtained in autonomous self-calibration technique helps to identify the imaged stars with the cataloged stars. Least Square based second method utilizes inertial star coordinates to determine satellite attitude and star camera parameters with lens radial distortion, both independent of each other. Camera parameters determined by the second method are more accurate than the first method of camera self calibration. Moreover, unlike most of the attitude determination algorithms where attitude of the satellite depend on the camera calibrating parameters, the second method has the advantage of computing spacecraft attitude independent of camera calibrating parameters except lens distortions (radial). Finally Kalman filter based sequential estimation scheme is employed to filter out the noise of the LS based estimation