Pitch Roll Research Articles

Investigation of Roll Pitch Yaw Phenomena for a Finned Store Released from a Wing

In this article, the commercial software CFD FASTRAN is applied to study the roll, pitch and yaw phenomena of turbulent flows around a finned store released from a wing. The three-dimensional, unsteady Navier-Stokes equations and k-e turbulent model are solved in the Cartesian coordinate system. The Chimera two-block grid system is utilized, and grid communication among two blocks are automatically implemented. To evaluate the accuracy of the present calculation, the calculated instantaneous trajectories of center of gravity of store, angles of roll, pitch and yaw, velocities and angular rates are compared with those of experimental data. The satisfactory agreement is achieved. Then, computations of different values of Mach number and ejector force applied on the store are carried out to investigate the unsteady roll, pitch and yaw phenomena of the separated store. The maximum value of pitch rate of the store decreases as the Mach number increases, and time of maximum value of yaw rate shortens as well. Both roll and yaw rates decrease as the ejector force applied on the store increases, and time of maximum value of roll, pitch and yaw rates shortens as well.

The Motion Attitude Analysis of High-Speed Tracked Vehicle Climbing over Vertical Wall

The research object is the motion attitude of the high-speed tracked vehicles climbing over the vertical wall. The new calculation method is used in calculating certain parameters of the equation and establishing the equation of driving characteristics. The changing equations of the pitch angle and roll angle when the high-speed tracked vehicles crossing the obstacles can be obtained. The analysis results show that the motion attitude when the high-speed tracked vehicles crossing the obstacles is related to the terrain parameters, the tracked vehicle parameters, the initial velocity when crossing the obstacles, and the motion attitude can be expressed by the mathematics equations. These results provide the research-based and the theory support for the modal and analysis of the high-speed tracked vehicles crossing over the obstacles, which have high practical value.

Turbulent Study of Roll Pitch Yaw Phenomena for a Finned Store Released from a Wing Regarding Different Values of Angle of Attack

In this article, the commercial software CFD FASTRAN is applied to study the roll, pitch and yaw phenomena of turbulent flows around a finned store released from a wing regarding different values of angle of attack. The three-dimensional, unsteady Navier-Stokes equations and standard k-ɛ turbulent model are solved in the Cartesian coordinate system. The Chimera two-block grid system is utilized, and grid communication among two blocks are automatically implemented. To evaluate the accuracy of the present calculation, the calculated instantaneous trajectories of center of gravity of store, angles of roll, pitch and yaw, velocities and angular rates are compared with those of experimental data. The satisfactory agreement is achieved. Then, computations of different values of angle of attack applied on the store are carried out to investigate the unsteady roll, pitch and yaw phenomena of the separated store. Longitudinally clockwise roll angle of store from pilot's viewpoint and yaw angle toward the wing tip decrease as the angle of attack increases. Maximum value of pitch angle increases as the angle of attack increases, and the time of maximum value of pitch angle increases as well.

Effect of Pitch and Roll Static Angle on Lubricant Transfer Between Disk and Slider

A precision spin stand was used to study the effects of pitch static angle and roll static angle on lubricant transfer between a disk and a slider in a hard disk drive. The lubricant distribution on the slider was determined by time- of-flight secondary ion mass spectrometry, while the lubri- cant distribution on the disks was obtained using optical surface analysis. Lubricant transfer from the disk to the slider was found to increase as a function of the pitch static angle of the slider. Negative roll static angles were found to have a larger effect on lubricant transfer and the formation of lubricant moguls than positive roll static angles. Suspension frequencies and pitch mode frequencies were observed in the lubricant mogul patterns for negative roll static angles.

Method of Attitude Measurement Based on the Geomagnetic and Gyroscope

The trajectory correction capability of the Simple guided munitions is directly affected by measurement accuracy of attitude angle. A gesture detection method based on geomagnetic gyro combination is proposed in this paper in order to detect the projectile flight attitude, The yaw angle of the projectile is solved by using runge-kutta algorithm with angle information of MEMS gyro. Then roll angle and pitch angle of the projectile is solved by magnetic field component of the three-axis magnetic sensor. Finally, the whole attitude detection system is installed in three-axis non-magnetic turntable to have a performance test. Experimental results show that the attitude solution results error is small. Nearby blind area, the roll angle error reduced to 5° and the pitch angle error reduced to 4°. In other locations, the roll angle error reduced to 2° and the pitch angle error reduce to 1°. The measurement accuracy increased nearly tenfold, can satisfy the trajectory correction demand of simple guidance ammunition.

Three-dimensional Feature Recognition-based Automated Patient Treatment Mismatch Verification System for Radiation Therapy

Three-dimensional Feature Recognition-based Automated Patient Treatment Mismatch Verification System for Radiation Therapy

Investigation of the Immobilization Capability of Open Masks for Head and Neck Patient Setup and Treatment

During Head and Neck treatment, some patients complain of claustrophobia due to the fully closed thermoplastic head masks. Recently introduced open mask solve this by exposing the patients' eyes, nose, and mouth. This study investigates the immobilization capability of open masks and proposes new CTV to PTV expansion margins for them. Open masks were deformed to custom-fit two volunteers using “C” size head pillows on a CT. After a number of days, the volunteers found the most comfortable position on the Linac treatment couch in the mask. A 3-D skin tracking system acquired a reference surface per volunteer. An ROI consisting of the eyes, nose, mouth, and part of cheek was selected per volunteer. The volunteer's setup ROI was tracked and rigidly registered to the reference ROI to calculate the skin surface's translation and rotation relative to the reference surface. The mask was removed, and the volunteer was asked to sit up. The setup was repeated five times to simulate daily setup uncertainties. In a second test, volunteers tried to remain still in the mask for 10 minutes to simulate the duration of a typical treatment. We recorded the translational and rotational real time deltas and the maximum deltas. The Results Table shows, per volunteer, the average deltas over the 5 setups and the corresponding standard deviations. We also report the maximum delta from reference observed during the 10-minute monitoring interval. We observed that the real time deltas increase slightly with time spent on the table, which is to be expected. Using a commonly accepted guideline (2.5×average + 0.7×standard deviation), we calculate the implied CTV to PTV expansion. Open masks generally solve claustrophobia. Based on our preliminary study, the conventional CTV to PTV expansion (3, 3, 3)mm should be altered to (2, 4, 4) mm for open mask usage. The open masks appear to provide sufficient immobilization. More volunteer study is scheduled to be done in the next several months.Poster Viewing Abstract 3389; TableStudy results (real time deltas)VolunteerMetricVertical (mm)Lateral (mm)Longitudinal (mm)Yaw (degrees)Roll (degrees)Pitch (degrees)1Average delta-0.9-1.7-0.3-0.10.41.31St. dev. of delta0.861.190.550.890.840.491Max delta in 10 minutes0.40.60.70.20.3-0.31Expansion1.73.40.50.31.73.62Average delta0.1-0.21.20.50.50.02St. dev. of delta2.120.451.100.520.481.022Max delta in 10 minutes0.40.60.70.20.3-0.32Expansion1.50.23.81.61.71.0 Open table in a new tab

Research on Genetic Characteristics of Slab Bulge in Continuous Casting Process

Bulge deformation is an important factor that causes inner crack and declines the quality for slab. This has a significant genetic phenomenon in continuous casting process. In order to explain this feature, a two-dimensional FEM model for slab that includes viscoelastic and dynamic characteristic has been built. Positive creep and reverse creep were introduced to explain this mechanism. Roll pitch, shell characteristic, slab withdrawing speed and other process parameters that influence bulge’s genetic level are discussed. A nonlinear equation was suggested to describe the relationships between these factors and genetic level of bulge.

Airborne geometry correction method for marine multispectrum data without attitude information

Marine airborne multispectrum scanner (MAMS) onboard the China marine surveillance plane can be used to survey marine environment, resources and disaster and provide the technical support for high-frequency, high-efficiency and high-resolution remote sensing monitoring for the coastal management. MAMS did not have the IMU/POS equipment, so it brought severe challenge for the geometry correction. One airborne geometry correction method is introduced for marine multi-spectrum data without the attitude information. First, it is the coarse geometry correction, which simulates the roll angle and pitch angle of plane according to the ideal flying model; the second step is the precise geometry correction by using the SPOT orthogonal projected data as the reference of registration, based on maximization of alignment metric method. With the validation, relative error of coarse correction is 81.42 m compared with SPOT data, and 11.3 m for precise correction. This method provides the high precision localization information for the oceanic remote sensing and application, and establishes the foundation for monitoring the marine resource and environment.

Comprehensive computational rollover sensitivity study, Part 1: influence of vehicle pre-crash parameters on crash kinematics and roof crush

In 2008, fatalities resulting from vehicle rollover events accounted for over one third of all fatalities resulting from motor vehicle crashes. This study describes the initial phase of a detailed computational study aimed at developing causal relationships between crash, occupant, and vehicle parameters and injury outcome using state-of-the-art computational methods. This initial phase examines the sensitivity of vehicle kinematics and structural deformation by isolating the roof-to-ground interaction phase of the rollover event using an LS-DYNA finite element full-vehicle model. Structural deformation is quantified by a measure of the maximum roof intrusion into the occupant space (average = 44 cm, range = 9–66 cm). Roll angle, pitch angle and drop height have a significant effect on structural deformation, while roll rate and yaw angle do not show significant effects. Drop height alone accounts for 70% of the variability in peak roof crush and vertical acceleration, metrics that are related to causal mechanisms for injury.

MEST of Round Blooms with Different Foot Roll Pitch Designing for Peritectic Steel Casting

The minimum mould exit shell thickness (MEST) is one of key factors to consider for continuous casting machine design. Based on the shell strength at elevated temperatures, a concept of shell integral average strength, from its very top surface to the solidus frontier, has been introduced to judge its bulging tendency under ferrostatic pressure. Considering the contribution for the foot roller designing, a mathematic model for the determination of the minimum MEST has been brought forward. It is shown that, when the minimal foot roll pitch is fixed, the minimum MEST is steady. But at the same time, when the MEST does not exceed the minimum value, the round bloom off-round would happen, it is worse for the round bloom than the bulging for the normal strand. And there is the cross point with the curve of the minimum MEST by the minimum roll pitch and the minimum MEST by the fluting include angle of the support roller and the lateral support roller against the cross section.

Model Test Study on Added Mass Coefficient of Four Buckets Foundation Ocean Platform

In this paper, the internal air pressure and bottom water pressure of the buckets, the acceleration of swaying, surging and heaving of platform were determined by the sensors fixed on the platform, as a naval bucket foundation platform for example. The motion rules of heave and sway of bucket foundations are studied with different drafts. The results of this test showed that the added mass coefficient of heave, roll and pitch are declined with the increase of the draft; the natural frequency of heave is constant with different drafts but the roll frequency and pitch frequency are consistent with the changes of the draft; the frequency of heave is larger than that of roll and pitch but the added mass coefficient of heave is lesser than that of roll and pitch.

Experimental Research on the Influences of Wave Height on Towing of 4-Bucket Foundation Platform

Internal air pressure and water pressure of the buckets foundation, acceleration and dragging force of the 4-bucket foundation platform were determined to analyze the influences of wave height on towing when 4-Bucket foundation platform is towing in conditions of a certain towing velocity, mooring point position and draught in different regular waves based on the model test. Comparing platform towing in following and head waves, the heave motion of the latter is more strenuous than that of the former; the stability and seakeeping of the former is better than those of the latter. Roll motion, pitch motion and heave motion appear aggravate phenomenon with the increase of wave height.

Shallow-water sloshing in vessels undergoing prescribed rigid-body motion in three dimensions

New shallow-water equations (SWEs), for sloshing in three dimensions (two horizontal and one vertical) in a vessel which is undergoing rigid-body motion in 3-space, are derived. The rigid-body motion of the vessel (roll–pitch–yaw and/or surge–sway–heave) is modelled exactly and the only approximations are in the fluid motion. The flow is assumed to be inviscid but vortical, with approximations on the vertical velocity and acceleration at the surface. These equations improve previous shallow-water models. The model also extends to three dimensions the essence of the Penney–Price–Taylor theory for the highest standing wave. The surface SWEs are simulated using a split-step alternating direction implicit finite-difference scheme. Numerical experiments are reported, including comparisons with existing results in the literature, and simulations with vessels undergoing full 3-D rotations.

Semi-active suspension control to improve ride and handling using magnetorheological (MR) damper

This paper presents the simulation study of a semi-active suspension system using non-parametric model of magnetorheological (MR) damper. Hybrid stability augmentation-force control (HSAS-FC) is proposed as the control algorithm. The performance of the proposed control algorithm is analysed using validated full vehicle model and compared with modified hybrid skyhook groundhook control and passive system. The HSAS-FC is used to estimate the desired force needed to simultaneously improve ride dynamics and handling performance. The stability augmentation system (SAS) is to improve ride, meanwhile the force control (FC) is used to control roll rate and pitch rate due to lateral load transfer and longitudinal load transfer. An adaptive inverse current model was developed to produce the required current by the MR damper. The results show the new system is effective in isolating vehicle body from unwanted motions at the body centre of gravity. The amplitude and settling time of unwanted body motions are reduce for ride.

Nonlinear Dynamics and Internal Resonances of a Ship With a Rectangular Cross-Section in Head Seas

Finite amplitude dynamics of ships in head seas due to parametric instabilities is a subject of renewed interest with an increasing demand of operation in severe and variable environmental conditions. In this current study we investigate the nonlinear dynamics and internal resonances of a ship with a rectangular cross-section in head seas. We employ an asymptotic averaging method to obtain the slowly varying system evolution dynamics for the weakly nonlinear response, complemented by numerical integration in the strongly nonlinear regime. A weakly nonlinear frequency response is obtained analytically for a principal parametric resonance and a 1:1 roll—pitch internal resonance. Comparison of results with three degrees of freedom numerical simulations reveals a good fit. A strongly nonlinear numerical analysis reveals that beyond the stability thresholds, the system’s responses included quasiperiodic dynamics. This combined approach resolves both parametric instabilities and internal resonances induced for both weak and finite nonlinear interactions, and culminates with criteria for orbital stability thresholds describing the onset of quasiperiodic response and magnification of energy transfer between coupled pitch-heave and ship roll.

Sea keeping analysis of air cushion vehicle with different wave angles under the operation resistance

The air cushion vehicle (ACV) sea keeping characteristic under different wave directions with the operation resistance is discussed with the couples of the heave, pitch roll motion and the pressure of the cushion. In previous researches, only wave and cross wave direction were discussed. Then a Matlab program is made to calculate the united frequency responses of heave, pitch and roll amplitude of the craft, under different wave frequencies and different wave directions. The results of the research depict some dangerous situations under which the sympathetic vibration happens in heave, pitch and roll motion and the amplitudes are extremely higher than those under the ordinary conditions. These results will be helpful in ACV design and operation.

G-load tracking control of a centrifuge driven by servo hydraulic systems

The centrifuge is applied as a training device to increase the tolerance of pilots for high G z-loads during high-speed manoeuvres, and to study the inertia of major physiological systems of the body. In this study, a centrifuge is driven by three servo hydraulically driven control systems: the speed control system of the centrifuge, which is driven by hydraulic variable motors, and the roll angle and pitch angle control system of the gondola, which are driven by the hydraulic oscillators. By controlling the speed of the centrifuge and the angular position of the gondola, the G z-load of centrifuge can be controlled to achieve the required profile.

The design of spherical multilobe-cam mechanisms

Cam—roller mechanisms can be used in transmissions and robotic devices as an alternative to their bevel-gear counterparts. As bevel gears are used to couple shafts of intersecting axes, their cam-mechanism replacements are bound to have intersecting axes as well. This means that the contact surface of the cam must be conical, which leads to spherical cam mechanisms. Compared with gear transmissions, cam—roller mechanisms feature low friction, low backlash, and high strength. However, cam mechanisms may end up with a high pressure angle if negative action, a motion in which the cam is driven by mechanism rollers, occurs. This article reports the design of transmissions with spherical multilobe cams (MLCs), as a means to reduce the pressure angle. The kinematics of MLC, including profile generation, undercutting-avoidance, and transmission-quality evaluation, is studied here. A case study has been included, in which the synthesis of a spherical MLC transmission is undertaken as a means to improve the transmission quality of a spherical epicyclic gear train. This train was introduced with the purpose of producing a singularity-free, unlimited-workspace pitch—roll wrist.

Determination of the maximal singularity-free orientation workspace for the Gough–Stewart platform

This work addresses the determination of the maximal singularity-free orientation workspace at a prescribed position of the Gough–Stewart platform. Using the Roll–Pitch–Yaw angles (ϕ, θ, ψ), the orientation workspace at a prescribed position can be defined by up to 12 workspace surfaces. A numerical algorithm is developed to determine these 12 workspace surfaces in order to obtain the maximal singularity-free orientation workspace as well as the corresponding leg length ranges. Besides, to compare the maximal singularity-free orientation workspace with the maximal singularity-free sphere, an iterative algorithm for determining the maximal singularity-free sphere is also provided.