A Compensation Method for Setting Misalignment Error in Gyroscope Deterministic Error Estimation Test

Quadrotor is one type of unmanned aerial vehicle that has the ability to vertical takeoff and landing. In this research, a system designed to stabilize quadrotor during flight condition by maintaining at angle of roll, pitch, yaw, and x, y, and z axis position using LQR full state feedback with artificial neural network (ANN).The LQR full state feedback method uses 12 states with each K constant being tuned with ANN. This research implements ANN method to change feedback constant at angle of roll, pitch, and yaw and x, y, and z axis. The artificial neural network method uses 12 input layers, 12 hidden layers, and 1 output layer.Testing with ANN improved the rise time to ± 2.18 seconds at the roll angle, ± 1.23 seconds at the pitch angle, and ± 0.31 seconds at the yaw angle. Improved settling time value up to ± 2.41 seconds at roll angle, ± 1.23 seconds at pitch angle, and ± 1.07 seconds at yaw angle. Improved steady state eror value of ± 0.61% at roll angle, ± 4.88% at pitch angle, and ± 0.82% at the yaw angle.

The purpose of this research is to realize precise straight motion. The straight motion system used in the paper has an ability to control five degrees of freedom of a moving table; vertical and horizontal positions, and roll, pitch and yaw angles. For the purpose, two references are introduced; motion reference and absolute reference. Table motions are controlled relatively to the motion reference. A solid master is used for the motion reference because of its stability against changes of environment. A geometrical error of the motion reference causes motion errors of the table. To compensate these errors, motion errors relative to the absolute reference are measured. The paper proposes the liquid surface for the absolute reference. The liquid surface is used only to measure motion errors caused by the geometrical error because the liquid surface is not robust enough. After the compensation, straight motion accuracies of 0.2μm in vertical position, 0.1arc sec in roll angle and 0.3arc sec in pitch angle were achieved.

The flight dynamics of a spaceplane strongly depends on the flight environment, including the dynamic pressure, angle of attack, and Mach number. In addition, spaceplanes fly at pitch angles around 90° during powered and coasting ascent, and Euler angles are known to be coupled with roll and yaw angles at such pitch angles. In this paper, the control system for a spaceplane based on dynamic inversion theory is proposed. To avoid the problem of the singularity of Euler angles, the equation of state is written in terms of quaternions. The control laws are designed and evaluated in the following three cases: (1) The case where only the attitude error calculation of the control law using the Euler angle is modified. (2) The case where the vector part of the quaternion is used as the control variable. (3) The case where the vector part of the error quaternion is used as the control variable. Finally, the results of the numerical simulation show that Case (3) has the best control performance.KeywordsNonlinear controlDynamic inversionQuaternionAttitude controlSpaceplane

This paper proposes new concepts of configuration and attitude control of underwater towed vehicle to perform operation in both vertical and horizontal axis with stable attitude.The principal configuration composed of fuselage, main wing, horizontal tail, vertical canard, upper and lower vertical tails designed taking into account stability and manoeuvrability in vertical and horizontal planes. The manoeuvrability was estimated by use of lamped mass method for equilibrium equations of motion of towed cable and vehicle. The dynamic stability was analysed by use of eigenvalue analysis based on linear equations of motion.CCV (Control Configured Vehicle) technology was adopted to perform the attitude control. Three types of decoupled mode were considered, i) pitch angle and vertical velocity, ii) pitch angular velocity and vertical velocity, iii) roll angle, yaw angle and side slip velocity. Fuzzy algorithm was applied to CCV attitude control.The effect of motion of towing mother ship in waves was simulated numerically based on non-linear equations of motion of cable and vehicle to examine the effectiveness of attitude control in vertical axis. Not only drifts of velocity components and pitch angle, but also oscillation of pitch angle are remarkably suppressed.The effect of tidal current was simulated numerically to examine the attitude control in horizontal axis. Oscillations of side slip velocity, roll angle and yaw angle are almost eliminated.

In several motion control applications, e.g. in precise pointing devices and navigation systems, an accurate estimate of the attitude of a device in the world coordinate system is required. Readily available sensors used to estimate the attitude suffer from drift, magnetic disturbances, or a lack of information about the direction of the geodetic north. In this paper, an algorithm which estimates the attitude of a camera using camera images and a Digital Surface Model (DSM) referenced by GPS is proposed. The algorithm uses shape features of a skyline extracted from a camera image and synthetic skylines rendered from a DSM in order to estimate the roll and pitch angles, while the yaw angle is estimated using grid search. The algorithm was evaluated using roughly 600 camera images captured with varying pitch and yaw angles. The standard deviations from the ground truth, provided by a high precision pointing device, are 0.037° ,0.015°, and 0.018° for roll, pitch, and yaw respectively. The results indicate a higher precision than current camera attitude estimation algorithms using a DSM, while also providing a robust yaw estimate.

This paper details a method to improve accuracy of the land vehicle attitude estimation. It employs the vehicle model constraints to enhance the integration of GPS and a low-cost MEMS inertial measurement unit (MIMU) (GPS/MIMU). To improve the yaw angle estimation, we propose a lateral velocity constraint (LVC) aided method based on the observability analysis for the integrated fusion system. The theoretical analysis indicates that the yaw angle will be directly observed if LVC is augmented into the GPS/MIMU fusion algorithm. Furthermore, for LVC/MIMU system without GPS, the roll angle is always well estimated regardless of whether the vehicle is moving or stationary, and, surprisingly, the pitch angle can also be relatively accurately estimated if the vehicle is moving. Thus, when GPS is unavailable, the LVC/MIMU fusion is proposed by replacing the GPS measurement with the virtual measurement LVC. It is an encouraging improvement since the accumulating errors induced by gyro bias can be suppressed using MIMU alone. Moreover, to overcome the shortage that the pitch angle is not observed if the vehicle is stationary, we propose to fuse the gyros with gravity-based angles by Kalman filtering if the vehicle is detected motionless based on a switching rule. The experimental results compare favorably to theoretical analysis, showing that the proposed method can effectively improve the accuracy for land vehicle attitude estimation.

Standard helicopters use the propeller angle to alter the aerodynamic force and have been shown to be feedback linearizable with the pitch, yaw and roll angles being the flat outputs. In this work, a-two-degree-of-freedom, laboratory-scale helicopter-like system (termed the toycopter), where the aerodynamic force is manipulated using the propeller speed, is considered. For such a system the yaw and pitch angles are not flat outputs contrarily of the real helicopters. Moreover, the system does not seem to be flat and is shown to admit at most a one dimensional defect. Various properties of this system are investigated to illustrate the difficulties that arise in the control of the toycopter.

The installation conditions of fluidic oscillators embedded in a hump surface were numerically investigated to improve the separation control of the flow over the hump. Unsteady flow analysis was performed using three-dimensional Reynolds-averaged Navier–Stokes equations with a modified shear stress transport model. The numerical results were validated by comparing them to experimental data. Five geometric parameters were studied in a parametric study: the installation location, staggered location, pitch angle, roll angle, and yaw angle of the fluidic oscillators. The highest flow control performance was obtained when in-line fluidic oscillators were located just downstream of the separation point. Nonzero roll and yaw angles had favorable effects on the separation control, and the flow control was most sensitive to the pitch angle among the installation parameters.

Information about the emotional state of a person can be inferred from facial expressions. Emotion recognition has become an active research area in recent years in various fields such as Human Robot Interaction (HRI), medicine, intelligent vehicle, etc., The challenges in emotion recognition from images with pose variations, motivates researchers to explore further. In this paper, we have proposed a method based on geometric features, considering images of 7 yaw angles (−45°,−30°,−15°,0°,+15°,+30°,+45°) from BU3DFE database. Most of the work that has been reported considered only positive yaw angles. In this work, we have included both positive and negative yaw angles. In the proposed method, feature extraction is carried out by concatenating distance and angle vectors between the feature points, and classification is performed using neural network. The results obtained for images with pose variations are encouraging and comparable with literature where work has been performed on pitch and yaw angles. Using our proposed method non-frontal views achieve similar accuracy when compared to frontal view thus making it pose invariant. The proposed method may be implemented for pitch and yaw angles in future.

We developed a signal processing algorithm to determine three components of the velocity vector of a highly maneuverable aircraft. We developed an equation of the distance from an aircraft to an underlying surface. This equation describes a general case of random spatial aircraft positions. Particularly, this equation considers distance changes according to an aircraft flight velocity variation. We also determined the relationship between radial velocity measured within the radiation pattern beam, the signal frequency Doppler shift, and the law of the range changing within the irradiated surface area. The models of the emitted and received signals were substantiated. The proposed equation of the received signal assumes that a reflection occurs not from a point object, but from a spatial area of an underlying surface. It fully corresponds to the real interaction process between an electromagnetic field and surface. The considered solution allowed us to synthesize the optimal algorithm to estimate the current range and three components {Vx,Vy,Vz} of the aircraft’s velocity vector V→. In accordance with the synthesized algorithm, we propose a radar structural diagram. The developed radar structural diagram consists of three channels for transmitting and receiving signals. This number of channels is necessary to estimate the full set of the velocity and altitude vector components. We studied several aircraft flight trajectories via simulations. We analyzed straight-line uniform flights; flights with changes in yaw, roll, and attack angles; vertical rises; and landings on a glide path and lining up with the correct yaw, pitch, and roll angles. The simulation results confirmed the correctness of the obtained solution.

Quadcopter requires monitoring to determine the position and attitude of the object when flying. Attitude consists of roll, pitch, and yaw angles. In quadcopter monitoring is difficult when the object is flying away and outside the operator's viewing range. Monitoring requires a monitoring system to monitor objects further. One way that can be used to determine the position and motion of a quadcopter is by combining GPS technology and Inertial Sensor. This study discusses data acquisition to monitor the position, attitude, and value of reading the sulfur gas sensor in the quadcopter by combining GPS and Inertial Sensor. The communication module used is 433 MHz radio frequency with STM32F103 and the main microcontroller using STM32F4DISCOVERY. Data about accepted objects is then displayed through Visual C # in real time. Testing of latitude and longitude is done by tracking the path of the object, while testing roll, pitch, and yaw angles is done by placing the object in accordance with the reference angle.

Dynamic responses of a floating dock under corrosion-induced accidents are studied using a numerical method. The numerical model is proposed to calculate the dynamic responses of the floating dock during operations. It includes a six-degree-of-freedom (6-DOF) model, a hydrostatic force model, a hydrodynamic force model, and a hydraulic model. The effects of the corrosion-induced holes on the stability of the floating dock are investigated and the results show that the maximum pitch and roll angles are 0.18° and 0.69° respectively when there is one hole located at one tank. The maximum pitch and roll angles become 0.42° and 2.04° respectively when there are two holes located at different tanks. The results indicate that situations involving more than one corroded hole result in large roll and pitch angles, which ultimately increase the risk of the vessel capsizing. This analysis not only emphasizes potential hazards but also presents an opportunity for the maritime sector to enhance safety, operational efficiency, and environmental responsibility.

In this paper, we present a new control approach for a quadrotor mini-helicopter using the full state backstepping technique. The controller can set the helicopter track three Cartesian position and the yaw angle to their desired trajectories and stabilize the pitch and roll angles by varying the input signals of DC-motors. The quadrotor has been presented into three interconnected subsystems. The first one representing the under-actuated subsystem, gives the dynamic relation of the horizontal positions with the pitch and roll angles. The second fully-actuated subsystem represents the dynamic behavior of the vertical position and the yaw angle. The last subsystem gives the dynamic of the four rotors propeller system. The design controller methodology is based on the Lyapunov stability theory. Various simulations of a quadrotor show the good performance of the proposed control law. Finally, we present initial flight experiments where the mini-helicopter is restricted to vertical and yaw motions.

We have been developing a rice-duck farming robot. The robot has functions of cackling, wing flapping, and feeding for gathering and leading real ducks. Our previous research results showed that these functions effectively gather and lead real ducks for weed areas in a paddy field. The robot has a tilt sensor and an acceleration sensor for measuring pitch, roll, and yaw angles of the robot's body, and has a front view camera for autonomous locomotion control. We designed and implemented a pitch angle control system and a roll angle control system for the robot. By using the roll angle of the robot's body, control parameters for crawlers are revised for stabilization of autonomous locomotion. By using the pitch angle of the robot's body, pitch angle of the front view camera is revised for stabilization of appropriate image processing and autonomous locomotion. The stabilization of autonomous locomotion in marshy paddy fields was verified through experiments in an indoor rice paddy.

Wind Engineering Analysis of Parabolic Trough Collectors to Optimise Wind Loads and Heat Loss