Time-Optimal Attitude Reorientation at Constant Angular Velocity Magnitude with Bounded Angular Acceleration

2006 ◽  
Author(s):  
Mrityunjay Modgalya ◽  
Sanjay P. Bhat
Keyword(s):  
Angular Velocity ◽  
Angular Acceleration ◽  
Constant Angular Velocity ◽  
Velocity Magnitude ◽  
Time Optimal

scholarly journals Analysis of the Dynamic Response of the Mechanism of Conventional Sucker rod Pumping Units

2020 ◽  
Vol 71 (1) ◽  
pp. 395-399
Author(s):  
Dorin Badoiu ◽  
Georgeta Toma
Keyword(s):  
Angular Velocity ◽  
Dynamic Response ◽  
Angular Acceleration ◽  
Constant Angular Velocity ◽  
Sucker Rod ◽  
Motion Parameters ◽  
Pumping Unit ◽  
Polished Rod ◽  
Pumping Units

In the kinetostatic study of the mechanism of the sucker rod pumping units, the cinematic motion parameters of the elements are considered to be known, assuming that the cranks have a constant angular velocity imposed by the operating functioning conditions of the pumping unit. The paper analyzes the dynamic response of the mechanism of these pumping units, which implies the determination of the variation of the angular acceleration of the cranks during the operating cinematic cycle. A series of results regarding the determination of the variation of the angular acceleration of the cranks during the cinematic cycle in the case of the mechanism of a C-640D-305-120 pumping unit are presented. The obtained results are checked by comparing the experimental curves of variations of the acceleration at the polished rod with those obtained by simulation using a computer program developed by the authors in which the angular acceleration of the cranks was taken into consideration.

scholarly journals Rotation Experiments with Blind Goldfish

1957 ◽  
Vol 34 (2) ◽  
pp. 259-275
Author(s):  
F. R. HARDEN JONES
Keyword(s):  
Angular Velocity ◽  
Centrifugal Force ◽  
Constant Velocity ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Mechanical Stimulus ◽  
Constant Angular Velocity ◽  
Water Current

1. Blind goldfish react to rotation at constant angular velocity by swimming against the direction of rotation so as to maintain, on the whole, the same orientation or bearing relative to earth. 2. The lowest angular velocity to which the fish appear to react is below 10°/sec. For the best performers the threshold is about 3°/sec. 3. The stimulus to which the fish responds is not one of contact, initial swirl or water current (when the turntable gets under way), variation in turntable velocity or centrifugal force. 4. The semicircular canals are probably the sensory channels through which a fish is able to detect rotation at constant velocity and the mechanical stimulus to which it responds is probably an angular acceleration. How the fish becomes aware of angular accelerations during rotation at constant velocity is not yet understood.

Mathematical modeling of Couette flow in anomalous thermoviscous liquid

2011 ◽  
Vol 8 (1) ◽  
pp. 143-152
Author(s):  
S.F. Khizbullina
Keyword(s):  
Mathematical Modeling ◽  
Angular Velocity ◽  
Numerical Experiment ◽  
Temperature Dependence ◽  
Steady Flow ◽  
Couette Flow ◽  
Outer Cylinder ◽  
Flow Regimes ◽  
Constant Angular Velocity ◽  
Coaxial Cylinders

The steady flow of anomalous thermoviscous liquid between the coaxial cylinders is considered. The inner cylinder rotates at a constant angular velocity while the outer cylinder is at rest. On the basis of numerical experiment various flow regimes depending on the parameter of viscosity temperature dependence are found.

Kinematics of rotation in place during defense turning in the crayfish Procambarus clarkii

2001 ◽  
Vol 204 (3) ◽  
pp. 471-486 ◽  
Author(s):  
N. Copp ◽  
M. Jamon
Keyword(s):  
Angular Velocity ◽  
Procambarus Clarkii ◽  
Angular Acceleration ◽  
The Body ◽  
Simple Variation ◽  
Freely Behaving ◽  
Leg Motion ◽  
Two Phases ◽  
Analysis System ◽  
Final Orientation

The kinematic patterns of defense turning behavior in freely behaving specimens of the crayfish Procambarus clarkii were investigated with the aid of a video-analysis system. Movements of the body and all pereiopods, except the chelipeds, were analyzed. Because this behavior approximates to a rotation in place, this analysis extends previous studies on straight and curve walking in crustaceans. Specimens of P. clarkii responded to a tactile stimulus on a walking leg by turning accurately to face the source of the stimulation. Angular velocity profiles of the movement of the animal's carapace suggest that defense turn responses are executed in two phases: an initial stereotyped phase, in which the body twists on its legs and undergoes a rapid angular acceleration, followed by a more erratic phase of generally decreasing angular velocity that leads to the final orientation. Comparisons of contralateral members of each pair of legs reveal that defense turns are affected by changes in step geometry, rather than by changes in the timing parameters of leg motion, although inner legs 3 and 4 tend to take more steps than their outer counterparts during the course of a response. During the initial phase, outer legs 3 and 4 exhibit larger stance amplitudes than their inner partners, and all the outer legs produce larger stance amplitudes than their inner counterparts during the second stage of the response. Also, the net vectors of the initial stances, particularly, are angled with respect to the body, with the power strokes of the inner legs produced during promotion and those of the outer legs produced during remotion. Unlike straight and curve walking in the crayfish, there is no discernible pattern of contralateral leg coordination during defense turns. Similarities and differences between defense turns and curve walking are discussed. It is apparent that rotation in place, as in defense turns, is not a simple variation on straight or curve walking but a distinct locomotor pattern.

Mathematical Models of Control Systems of Angular Speed of Steam Turbines for Diagnostic Tests of Automatic and Mechatronic Devices

2013 ◽  
Vol 198 ◽  
pp. 519-524
Author(s):  
Grzegorz Redlarski ◽  
Janusz Piechocki ◽  
Mariusz Dąbkowski
Keyword(s):  
Angular Velocity ◽  
Power System ◽  
Control Systems ◽  
Working Conditions ◽  
Diagnostic Tests ◽  
Angular Acceleration ◽  
Angular Speed ◽  
Physical Parameters ◽  
Steam Turbines ◽  
Parallel Operation

In many automatics and mechatronics systems accurate modeling of several physical processes is needed. In power system, one of these is the process of control of angular velocity of power blocks during their connection to parallel operation. This process is extremely dynamic and the response of control system results from continuous changes in many physical parameters (temperature, pressure and flow of the working medium, etc.). An accuracy of modeling this process influences int. al. on: quality of the automatic synchronizer diagnostic tests in the laboratory, as well as the possibility of evaluation of prospects for connection process in the power system, without the automatic synchronizer [. Automatics systems used for research and diagnosis of automatic synchronizers are known in the literature as and simulators [2, . To impose similar to real working conditions, it is required to implement an appropriate models of control systems. One of such models, representative for the larger population of objects, is model of control systems of angular velocity. Currently used models, e.g. [3, 4, 5, , allow to approximate the response of real object, or to impose higher restricted conditions of work, for example: related to the angular acceleration dω/dt, the size of overshoots and decay time of transitional characteristics, while accurate modeling the real working conditions using them is not possible. Furthermore, their use requires knowledge of the (often difficult to access) object parameters and time-consuming selection of manual procedure of certain substitute settings, occurring in these models. To eliminate inconveniences mentioned above, in the paper the proposal and mathematical modeling procedure is presented, which allow to obtain much more accurate transitional characteristics of real objects.

Gyroscope-Free Link Parameter Measurement Using Accelerometers and Magnetometer

2014 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Inertial Sensors ◽  
Angular Acceleration ◽  
Parameter Measurement ◽  
Joint Angles ◽  
Symmetry Constraint ◽  
Estimation Techniques ◽  
Angular Velocities ◽  
Joint Parameters

Knowledge of joint angles, angular velocities is essential for control of link mechanisms and robots. The estimation of joint angles and angular velocity is performed using combination of inertial sensors (accelerometers and gyroscopes) which are contactless and flexible at point of application. Different estimation techniques are used to fuse data from different inertial sensors. Bio-inspired sensors using symmetrically placed multiple inertial sensors are capable of instantaneously measuring joint parameters (joint angle, angular velocities and angular acceleration) without use of any estimation techniques. Calibration of inertial sensors is easier and more reliable for accelerometers as compared to gyroscopes. The research presents gyroscope-less, multiple accelerometer and magnetometer based sensors capable of measuring (not estimating) joint parameters. The contribution of the improved sensor are four-fold. Firstly, the inertial sensors are devoid of symmetry constraint unlike the previously researched bio-inspired sensors. However, the accelerometer are non-coplanarly placed. Secondly, the accelerometer-magnetometer combination sensor allows for calculation of a unique rotation matrix between two link joined by any kind of joint. Thirdly, the sensors are easier to calibrate as they consist only of accelerometers. Finally, the sensors allow for calculation of angular velocity and angular acceleration without use of gyroscopes.

The Swimming of Nymphon Gracile (Pyconogonida)

1971 ◽  
Vol 55 (1) ◽  
pp. 273-287
Author(s):  
ELFED MORGAN
Keyword(s):  
Angular Velocity ◽  
Hydrodynamic Force ◽  
Beat Frequency ◽  
High Elevation ◽  
Dorsal Side ◽  
Constant Angular Velocity ◽  
Power Stroke ◽  
Lateral Thrust ◽  
Constant Depth ◽  
Recovery Stroke

1. The organization of the swimming legs of N. gracile has been described. The legs beat ventrally so the animal swims with the dorsal side foremost. The joints between the major segments of the leg are extended for most of the power stroke, but the distal segments articulate sequentially later in the beat, commencing with the flexion of the femoro-tibial joint at the end of the power stroke. Continued flexion reduces the leg radius considerably during the recovery stroke. 2. Animals swimming at constant depth were found to have a leg-beat frequency of about 1 beat/s. Above this the rate of ascent increased rapidly with increasing frequency of beat. Abduction or adduction of the leg usually occurred prior to the start of the power stroke with the femur in the elevated position. 3. Assuming a fixed limb profile at constant angular velocity, maximum lift was calculated to have occurred with the femur inclined at an angle of about 50° to the dorso-ventral body axis. The outward component of the lateral thrust decreased to zero at this point, and with further declination of the femur the lateral forces became inwardly directed. Of the different segments of the leg, tibia 2 and the tarsus and propodium contribute most of the hydrodynamic force. 4. The angular velocity of the leg varied during the power stroke, and the actual forces generated during two beats having the same amplitude and angular velocity but of high and low elevation were calculated. Greater lift occurred during the high-elevation beat when the leg continued to provide lift throughout the power stroke, whereas the low-elevation beat acquired negative lift values towards the end of the power stroke. The lateral thrust was now directed entirely inwards.

The Mathematic Model and Method for Solving the Dirichlet Heat-Exchange Problem for Empty Isotropic Rotary Body

2018 ◽  
Vol 277 ◽  
pp. 168-177
Author(s):  
Mykhailo Berdnyk
Keyword(s):  
Temperature Field ◽  
Dirichlet Problem ◽  
Heat Exchange ◽  
Angular Velocity ◽  
Integral Transformation ◽  
Mathematic Model ◽  
Constant Angular Velocity ◽  
Temperature Fields ◽  
Finite Velocity ◽  
Finite Space

It is the first generalized 3D mathematic model, which is created for calculating temperature fields in the empty isotropic rotary body, which is restricted by end surfaces and lateral surface of rotation and rotates with constant angular velocity around the axis OZ, with taking into account finite velocity of the heat conductivity in the form of the Dirichlet problem. In this work, an integral transformation was formulated for the 2D finite space, with the help of which a temperature field in the empty isotropic rotary body was determined in the form of convergence series by the Fourier functions.

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