scholarly journals Optimization of a New High Rotary Missile-Borne Stabilization Platform

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4143 ◽  
Author(s):  
Wei ◽  
Li ◽  
Zhang ◽  
Feng ◽  
Zhang ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Inertial Sensors ◽  
Simulation Analysis ◽  
Calculation Model ◽  
Friction Torque ◽  
Working Environment ◽  
Friction Moment ◽  
Nested Structure ◽  
Stabilized Platform ◽  
Bearing Structure

The passive semi-strapdown roll stabilized platform is an inertial platform, which can isolate the rolling of a projectile body by a special mechanical device. In the passive semi-strapdown roll stabilized platform, the bearing device plays an important role in isolating the rolling of the projectile body. The smaller the friction moment of bearing, the smaller the swing angular velocity of the platform, the smaller the range of inertial sensors required, the higher the accuracy of the navigation solution. In order to further reduce the swing angular velocity of the platform and improve the navigation accuracy, the bearing nested structure that could reduce the friction torque is proposed. Combined with the working principle of the passive semi-strapdown roll stabilized platform, the mechanical calculation model of friction at the moment of bearing the nested structure was established. A series of simulation analysis and tests showed that the output stability value of the friction moment was 47% that of a single bearing; the roll rate of the platform based on the bearing nested structure decreased to 50% of that based on the single bearing structure; the position and attitude errors measured of the platform based on the bearing nested structure decreased to more than 50% of that based on the single bearing structure. It showed that the bearing nested structure could effectively reduce the friction moment, improve the axial reliability of the bearing, and provide a more stable working environment for the passive semi-strapdown roll stabilized platform.

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.

scholarly journals A Novel Separated Position and Orientation System Integrated with Inertially Stabilized Platform

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Yanshun Zhang ◽  
Shuangji Feng ◽  
Zhanqing Wang ◽  
Xiaopeng Xi ◽  
Ming Li
Keyword(s):  
Inertial Sensors ◽  
Orientation System ◽  
Imaging Payloads ◽  
Position And Orientation ◽  
Velocity Motion ◽  
Stabilized Platform ◽  
Application Requirements ◽  
Inertially Stabilized Platform ◽  
Centralized System ◽  
Effective Function

Considering the application requirements of independent imaging payloads design, a novel scheme of separated position and orientation system (POS) is proposed, in which the high-precision inertial sensors of traditional centralized POS fixed on the imaging payloads are mounted on three gimbals of the inertially stabilized platform (ISP), respectively, and make them integrated. Then, the kinematics model of the ISP system is built to transmit the inertial information measured by separated inertial sensors mounted on ISP gimbals and flight body to the imaging payloads, calculating the position and attitude of the imaging payloads to achieve the function of separated POS. Based on the model, a series of simulations indicate that the precision difference between separated system and centralized system is ignorable under the condition of angular motion and variable velocity motion. Besides the effective function equal to traditional centralized system, the separated POS enhances the integration with the ISP. Moreover, it improves the design independence of the imaging payloads significantly.

Roof Cover Impact on Cooling Energy Use of Office Buildings

2014 ◽  
Author(s):  
Moncef Krarti
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Simulation Analysis ◽  
Calculation Model ◽  
Office Building ◽  
Climate Zones ◽  
Building Energy Use ◽  
Detailed Simulation ◽  
Simplified Calculation ◽  
The Impact

This paper analyzes the impact of roof covers on office building energy use for representative US climate zones. In particular, the study presented in the paper investigates the potential annual cooling energy use savings that roof covers could provide using whole-building simulation analysis to evaluate the performance of a 2-story office building in five US locations. Three parameters of the roof covers including their size, height, and transmittance, are considered in the analysis. The simulation results indicate that while roof covers had similar affects on buildings in all climate zones, their impact in reducing cooling energy usage is different and is more pronounced in cooler climates. Specifically, roof covers could potentially achieve cooling energy savings of up to: 25% in Houston, 33% in Atlanta, 31% in Nashville, 38% in Chicago, and 41% in Madison. Based on the detailed simulation analysis results, a simplified calculation model is developed to help the estimation of cooling energy savings as a function of the roof cover size, height, and transmittance.

Effect of roughness on sealing performance of oil seals with surface texture

2019 ◽  
Vol 72 (4) ◽  
pp. 525-532
Author(s):  
Fuying Zhang ◽  
Junmei Yang ◽  
Haoche Shui ◽  
Chengcheng Dong
Keyword(s):  
Film Thickness ◽  
Surface Texture ◽  
Equilateral Triangle ◽  
Friction Torque ◽  
Working Environment ◽  
Correct Selection ◽  
Deformation Analysis ◽  
Rotating Shaft ◽  
Pumping Rate ◽  
Content Type

Purpose This paper aims to obtain the film thickness, friction torque and pumping rate and analyze the effects of roughness and surface micro-dimple texture (circular, square and equilateral triangle) on the performance of the oil seal. Design/methodology/approach On the basis of elastohydrodynamic lubrication and the pumping mechanism of rotating shaft seal, this paper establishes a numerical model of hybrid lubrication of oil seal in sealing area. The model is coupled with fluid mechanics, rough peak contact mechanics and deformation analysis. Findings The results show that surface texture significantly improves the lubrication properties of the oil seal. The oil seal with the square texture has the largest oil film thickness, while the equilateral triangle texture has a better effect on the pumping rate. Originality/value To get closer to the real working environment of the oil seal, based on the surface roughness, this paper studies the effect of the texture shapes applied to the oil seal lip surface on the performance of the oil seal. The critical roughness and rotational speed values with zero pumping rate are obtained, which provides a theoretical basis for the correct selection of oil seals.

scholarly journals Proposal of an Equal-Stiffness and Equal-Stroke 2D Micro-Positioning Platform Driven by Piezoelectric Actuators

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 47
Author(s):  
Feng Sun ◽  
Yansong Hao ◽  
Fangchao Xu ◽  
Junjie Jin ◽  
Qiang Li ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Structural Parameters ◽  
Piezoelectric Actuators ◽  
Static Stiffness ◽  
Coupling Ratio ◽  
Stiffness Analysis ◽  
Magnification Ratio ◽  
Measurement Experiment ◽  
Nested Structure ◽  
Long Stroke

Micro-positioning platform plays an important role in the field of precision positioning such as microelectronics, robotics and biomedicine. This paper proposes an equal-stiffness and equal-stroke 2D micro-positioning platform, which is driven by piezoelectric actuators. The overall structure of the 2D micro-positioning platform adopts a nested structure and the displacement magnification mechanism adopts two hourglass displacement magnification mechanisms. The displacement magnification ratio of the hourglass displacement magnification mechanism was studied, and its structural parameters were optimized. Static stiffness analysis and simulation analysis of the micro-positioning platform were carried out. The simulation stiffness of the micro-positioning platform in the XY direction is 46873 N/m and 46832 N/m respectively. The experimental prototype of the micro-positioning platform was built. Through the measurement experiment with the prototype, the maximum stroke of the micro-positioning platform in the XY direction is 489 μm and 493 μm respectively; the maximum coupling ratio in the XY direction is 2.38% and 2.70% respectively. The research indicates that the micro-positioning platform had the characteristics of small size, equal long stroke, equal stiffness and low coupling ratio in the XY direction.

The Model Establishment and Simulation Analysis of Controllable Pendulum

2014 ◽  
Vol 599-601 ◽  
pp. 714-717
Author(s):  
Fan Li ◽  
Geng Biao Shen ◽  
Zi Chao Zhang ◽  
Jian Hui Zhao
Keyword(s):  
Autonomous Navigation ◽  
Simulation Analysis ◽  
Pendulum System ◽  
Loop Control ◽  
Inverted Pendulum System ◽  
Preliminary Validation ◽  
Closed Loop Control System ◽  
Moving Base ◽  
Loop Control System ◽  
Stabilized Platform

Indicating vertical in moving base to establish horizontal reference is of great significance for the near-earth autonomous navigation. Existing vertical indicating device achieves the goal by using gyro stabilized platform, but the gyroscope is difficult to maintain and has drift error. This paper proposes controllable pendulum system that is a stable closed-loop control system and similar to inverted pendulum system to accomplish the purpose. This paper covers the preliminary validation of the controllable system’s ability of indicating vertical in pulse interference cases and raises the defects of system under condition of step disturbance, by establishing mathematical model, designing double output PID controller and analyzing error , which lays the foundation for follow-up study.

Research on the Composite Control Scheme for the Stabilized Loop of Inertial Stabilized Platform

2014 ◽  
Vol 621 ◽  
pp. 209-214
Author(s):  
Hong Bo Liao ◽  
Shi Xun Fan ◽  
Mo Hei ◽  
Da Peng Fan
Keyword(s):  
Control Structure ◽  
Control Method ◽  
Friction Torque ◽  
Experimental Setup ◽  
Sensor Noise ◽  
Composite Control ◽  
Control Scheme ◽  
Stabilized Platform ◽  
Composite Control Scheme ◽  
Peak Value

A composite control scheme is proposed to solve the problems of friction toque and carrier disturbance lag in the stabilized loop of inertial stabilized platform. Based on analysis of composite control structure, the performance of single rate loop, double rate loop and composite control in the inhibition of carrier disturbance, friction torque and sensor noise are compared. In order to further verify the composite control method, an experimental setup is built. The experimental results show that: when the disturbance is 1deg-1Hz sinusoidal signal, the peak value of residual error of the single rate loop is 0.055 deg, the double rate loop is 0.031deg, and the composite control is the 0.0188deg, so the performance of isolation carrier disturbance of platform is effectively improved.

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