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Absolute Angular Velocity

The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform

Yu. N. Chelnokov – 1st expert on this subject based on the ideXlab platform

  • A New Method of Integrating the Equations of Autonomous Strapdown INS
    Mekhatronika Avtomatizatsiya Upravlenie, 2018
    Co-Authors: Ya. G. Sapunkov, Yu. N. Chelnokov, A. V. Molodenkov

    Abstract:

    We propose the new version of separating the process of integrating the differential equations, which describe the functioning of the strapdown inertial navigation system (SINS) in the normal geographic coordinate system (NGCS), into rapid and slow cycles. In this version, the vector of the relative Velocity of an object is represented as a sum of a rapidly changing component and a slowly changing component. The equation for the rapidly changing component of the relative Velocity includes the vectors of Angular velocities of the Earth’s rotation, NGCS rotation, and, at the same time, the vectors of the apparent acceleration and gravity acceleration, because these accelerations partially balance each other, and at rest relative to the Earth are balanced completely. The equation of the slowly changing component of the relative Velocity includes only the vector of Angular Velocity of the Earth’s rotation and the vector of NGCS rotation. The quaternion orientation of an object relative to the NGCS is represented as a product of two quaternions: a rapidly changing one, which is determined by the Absolute Angular Velocity of an object, and slowly changing one, which is determined by the Angular Velocity of the NGCS. The right parts of the equations for each group of variables depend on the rapidly changing and slowly changing variables. In order to enable the independent integration of the slow and rapid cycle equations, the algorithm have been developed for integrating the equations using the predictor and corrector for the cases of instantaneous and integral information generated by SINS sensors. At each predictor step the Euler method is used to estimate the longitude, latitude and altitude of an object, slowly changing component of the relative Velocity, and slowly changing multiplier of the orientation quaternion at the rightmost point of the slow cycle. Then the Euler-Cauchy method is used to integrate the equations for the rapidly changing components on the rapid cycle intervals, which are present in the slow cycle. The necessary values of the slowly changing components in the intermediate points are calculated using the formulas of linear interpolation. After the rapidly changing components are estimated at the rightmost point of the slow cycle, at the corrector step the Euler-Cauchy method is used to refine the values of the slowly changing components at the rightmost point of the slow cycle. Note that at the beginning of each slow cycle step the slowly changing component of Velocity is equal to the value of the relative Velocity of an object, and the rapidly changing component is zero. Similarly, at the beginning of each slow cycle step the slowly changing multiplier of object’s orientation quaternion equals to the quaternion of orientation of an object relative to the NGCS, and the rapidly changing multiplier of the orientation of an object has its scalar part equal to one, and its vector part equal to zero (this formula is derived from the quaternion formula for adding the finite rotations). SINS on a stationary base had been simulated in the presence of perturbations for a large time interval for a diving object, which drastically changes its height over short time periods.

  • Kinematic problem of optimal nonlinear stabilization of Angular motion of a rigid body
    Mechanics of Solids, 2017
    Co-Authors: V. G. Biryukov, Yu. N. Chelnokov

    Abstract:

    The problem of optimal transfer of a rigid body to a prescribed trajectory of preset Angular motion is considered in the nonlinear statement. (The control is the vector of Absolute Angular Velocity of the rigid body.) The functional to be minimized is a mixed integral quadratic performance criterion characterizing the general energy expenditure on the control and deviations in the state coordinates.

  • Kinematic problem of optimal nonlinear stabilization of Angular motion of a rigid body
    Mechanics of Solids, 2017
    Co-Authors: V. G. Biryukov, Yu. N. Chelnokov

    Abstract:

    The problem of optimal transfer of a rigid body to a prescribed trajectory of preset Angular motion is considered in the nonlinear statement. (The control is the vector of Absolute Angular Velocity of the rigid body.) The functional to be minimized is a mixed integral quadratic performance criterion characterizing the general energy expenditure on the control and deviations in the state coordinates. Pontryagin’s maximum principle is used to construct the general analytic solution of the problem in question which satisfies the necessary optimality condition and ensures the asymptotically stable transfer of the rigid body to any chosen trajectory of preset Angular motion. It is shown that the obtained solution also satisfies Krasovskii’s optimal stabilization theorem.

Huaidong Zhang – 2nd expert on this subject based on the ideXlab platform

  • the effectiveness of gait event detection based on Absolute shank Angular Velocity in turning
    International Conference on Advanced Robotics and Mechatronics, 2019
    Co-Authors: Wentao Sheng, Zhenyu Jiang, Xin Wang, Huaidong Zhang

    Abstract:

    Heel-strike (HS) and toe-off (TO) events of the human walking are the basis for gait analysis. The gait event detection algorithm is applied in the fields of spatio-temporal parameter analysis, rehabilitation, and wearable auxiliary devices. Based on the shank’s Absolute Angular Velocity in the sagittal plane, offline/online detection of HS-TO for normal walking, incline walking and other gaits in sagittal plane can be achieved. This type of detection algorithms assume that the motion occurs only in the sagittal plane, and the motion characteristics of the left and right shanks in one gait cycle are consistent. However, the effectiveness of this type of gait event detection algorithms for the turning gait is unclear. The turning gait in daily life is frequent and inevitable. Ignoring the gait event detection for the turning gait will limit the application of the existing gait event detection algorithms. To this end, this paper compared the degree of symmetry of the Absolute Angular Velocity of the left and right shanks under normal walking and turning gait. The validity of a typical HS-TO detection algorithm based on shank joint Angular Velocity is analyzed, and the necessity of studying the turning gait event detection algorithm is demonstrated.

  • ICARM – The Effectiveness of Gait Event Detection Based on Absolute Shank Angular Velocity in Turning
    2019 IEEE 4th International Conference on Advanced Robotics and Mechatronics (ICARM), 2019
    Co-Authors: Wentao Sheng, Zhenyu Jiang, Xin Wang, Huaidong Zhang

    Abstract:

    Heel-strike (HS) and toe-off (TO) events of the human walking are the basis for gait analysis. The gait event detection algorithm is applied in the fields of spatio-temporal parameter analysis, rehabilitation, and wearable auxiliary devices. Based on the shank’s Absolute Angular Velocity in the sagittal plane, offline/online detection of HS-TO for normal walking, incline walking and other gaits in sagittal plane can be achieved. This type of detection algorithms assume that the motion occurs only in the sagittal plane, and the motion characteristics of the left and right shanks in one gait cycle are consistent. However, the effectiveness of this type of gait event detection algorithms for the turning gait is unclear. The turning gait in daily life is frequent and inevitable. Ignoring the gait event detection for the turning gait will limit the application of the existing gait event detection algorithms. To this end, this paper compared the degree of symmetry of the Absolute Angular Velocity of the left and right shanks under normal walking and turning gait. The validity of a typical HS-TO detection algorithm based on shank joint Angular Velocity is analyzed, and the necessity of studying the turning gait event detection algorithm is demonstrated.

V. V. Sazonov – 3rd expert on this subject based on the ideXlab platform

  • Stabilization of the Solar Orientation Mode of an Artificial Earth Satellite by an Electromagnetic Control System
    Cosmic Research, 2018
    Co-Authors: A. I. Ignatov, V. V. Sazonov

    Abstract:

    The solar orientation mode of an artificial Earth satellite is investigated. Satellite parameters correspond to the parameters of the Bion M and Foton M-4 satellites. In this mode, the normal to the satellite solar cell plane is always directed to the Sun, the longitudinal axis lies in the plane of the orbit, and the satellite Absolute Angular Velocity is very small. The mode is stabilized by electromagnets that interact with the Earth magnetic field and a rotating flywheel that generates a constant gyrostatic moment along the satellite longitudinal axis. Such a moment can be generated using a reaction wheel system. The constancy of the gyrostatic moment means that this system will operate without saturation. The satellite attitude control is implemented by changing the currents in the electromagnets. Two control laws that reduce the satellite Angular Velocity and stabilize the solar orientation are investigated. Their implementation does not require complex measurements. It is sufficient to have the readings of a solar sensor and a triaxial magnetometer and equipment for their processing. The effectiveness of control laws is confirmed by the mathematical modeling of the satellite motion with respect to the center of mass under the influence of gravitational and aerodynamic moments, as well as the moment generated by electromagnets.

  • Estimation of residual microaccelerations on board an artificial earth satellite in the monoaxial solar orientation mode
    Cosmic Research, 2013
    Co-Authors: A. I. Ignatov, V. V. Sazonov

    Abstract:

    The mode of monoaxial solar orientation of a designed artificial Earth satellite (AES), intended for microgravitational investigations, is studied. In this mode the normal line to the plane of satellite’s solar batteries is permanently directed at the Sun, the Absolute Angular Velocity of a satellite is virtually equal to zero. The mode is implemented by means of an electromechanical system of powered flywheels or gyrodynes. The calculation of the level of microaccelerations arising on board in such a mode, was carried out by mathematical modeling of satellite motion with respect to the center of masses under an effect of gravitational and restoring aerodynamic moments, as well as of the moment produced by the gyrosystem. Two versions of a law for controlling the characteristic Angular momentum of a gyrosystem are considered. The first version provides only attenuation of satellite’s perturbed motion in the vicinity of the position of rest with the required Velocity. The second version restricts, in addition, the increase in the accumulated Angular momentum of a gyrosystem by controlling the angle of rotation of the satellite around the normal to the light-sensitive side of the solar batteries. Both control law versions are shown to maintain the monoaxial orientation mode to a required accuracy and provide a very low level of quasistatic microaccelerations on board the satellite.