Coupled Pitch Links for Multiharmonic Isolation Using Fluidic Circuits

2014 ◽  
Vol 59 (4) ◽  
pp. 1-11
Author(s):  
Lloyd H. Scarborough III ◽  
Christopher D. Rahn ◽  
Edward C. Smith ◽  
Kevin L. Koudela
Keyword(s):  
Experimental Validation ◽  
Analytical Models ◽  
Main Rotor ◽  
Fluidic Devices ◽  
Simulation Results ◽  
Fluidic Circuits ◽  
Blade Loads

Replacing stiff pitch links on rotorcraft with coupled fluidic devices has the potential to reduce the aerodynamic blade loads transmitted through the pitch links to the swashplate. Analytical models of two fluidic devices coupled with three different fluidic circuits are derived. These passive fluidlastic systems are tuned, by varying the fluid inertances and capacitances of each fluidic circuit, to reduce the transmitted pitch-link loads. The different circuit designs result in transmitted pitch-link loads reduction at up to three main rotor harmonics. The simulation results show loads reduction at the targeted out-of-phase and in-phase harmonics of up to 88% and 93%, respectively. Experimental validation of two of the fluidic circuits demonstrates loads reduction of up to 89% at the out-of-phase isolation frequencies and up to 81% at the in-phase isolation frequencies.

Coupled Pitch Links for Multi-Harmonic Isolation Using Fluidic Circuits

2012 ◽  
Author(s):  
Lloyd H. Scarborough ◽  
Christopher D. Rahn ◽  
Edward C. Smith ◽  
Kevin L. Koudela
Keyword(s):  
Analytical Models ◽  
Main Rotor ◽  
Fluidic Devices ◽  
Simulation Results ◽  
Fluidic Circuits ◽  
Blade Loads ◽  
Even Harmonics

Replacing rigid pitch links on rotorcraft with coupled fluidic devices has the potential to reduce the aerodynamic blade loads transmitted through the pitch links. Analytical models of two fluidic devices coupled with three different fluidic circuits are derived. These passive fluidlastic systems are tuned, by varying the fluid inertances and capacitances of each fluidic circuit, to reduce the transmitted pitch-link loads for up to three main-rotor harmonics. The simulation results show loads reduction at the targeted odd and even harmonics of at least 95% and 72%, respectively.

Comparison of Analytical and Empirical Models to Capture Variations in Off-Road Vehicle Dynamics

2005 ◽  
Author(s):  
Paul J. Pearson ◽  
David M. Bevly
Keyword(s):  
Empirical Data ◽  
Vehicle Dynamics ◽  
Experimental Validation ◽  
Inertial Sensors ◽  
Analytical Models ◽  
Control Algorithms ◽  
Model Parameters ◽  
Steering Control ◽  
Steering Angle ◽  
Yaw Rate

This paper develops two analytical models that describe the yaw dynamics of a farm tractor and can be used to design or improve steering control algorithms for the tractor. These models are verified against empirical data. The particular dynamics described are the motions from steering angle to yaw rate. A John Deere 8420 tractor, outfitted with inertial sensors and controlled through a PC-104 form factor computer, was used for experimental validation. Conditions including different implements at varying depths, as would normally be found on a farm, were tested. This paper presents the development of the analytical models, validates them against empirical data, and gives trends on how the model parameters change for different configurations.

scholarly journals Kinematic Analysis of Three-Wire-Driven Parallel (TWDP) Robot

2011 ◽  
Vol 2-3 ◽  
pp. 302-307 ◽  
Author(s):  
Tao Yu ◽  
Qing Kai Han
Keyword(s):  
Static Analysis ◽  
Parallel Robot ◽  
Analytical Models ◽  
Kinematics Analysis ◽  
Mechanism Model ◽  
Good Movement ◽  
Dynamics And Control ◽  
Movement Stability ◽  
Simulation Results ◽  
And Control

In the paper, a novel new gravity-constrained (GC) three-wire-driven (TWD) parallel robot is proposed. With its mechanism model, three typical kinematics analytical models, including horizontal up-down motion, pitching motion and heeling motion and their corresponding simulations are given in detail. In static analysis, the change of tensions in the wires is calculated based on previous kinematics analysis. The simulation results show the robot has good movement stability. The paper can provide useful materials to study of dynamics and control on wire-driven robot.

Investigation of Thermal Effect of Packaged CMOS Compatible Pressure Sensor

Manufacturing ◽  
2002 ◽  
Author(s):  
Chih-Tang Peng ◽  
Ji-Cheng Lin ◽  
Chun-Te Lin ◽  
Kuo-Ning Chiang
Keyword(s):  
Pressure Sensor ◽  
Output Voltage ◽  
Experimental Validation ◽  
Experimental Result ◽  
Pressure Loading ◽  
Simulation Data ◽  
Sensor Performance ◽  
Piezoresistive Pressure Sensor ◽  
Simulation Results ◽  
Stress Buffer

In this study, a packaged silicon base piezoresistive pressure sensor with thermal stress buffer is designed, fabricated, and measured. A finite element method (FEM) is adopted for design and experimental validation of the sensor performance. Thermal and pressure loading on the sensor is applied to make a comparison between sensor experimental and simulation results. Furthermore, a method that transfers simulation stress data into output voltage is proposed in this study, the results indicate that the experimental result coincides with simulation data.

Yaw Rate Estimation for Vehicle Control Applications

1998 ◽  
Vol 120 (2) ◽  
pp. 267-274 ◽  
Author(s):  
N. Sivashankar ◽  
A. G. Ulsoy
Keyword(s):  
Experimental Validation ◽  
Vehicle Control ◽  
Operating Conditions ◽  
Angle Sensor ◽  
Control Applications ◽  
Rate Estimation ◽  
Yaw Rate ◽  
Wide Range ◽  
Simulation Results ◽  
Instrumented Vehicle

This paper describes a method for vehicle yaw rate estimation using two accelerometers and a steer angle sensor. This yaw rate estimate can be used as an inexpensive alternative to commercial yaw rate sensors in vehicle control applications. The proposed method combines two complementary approaches to yaw rate estimation using accelerometers. This new method is superior to either method used by itself. This paper presents the new approach, supporting analyses, simulation results and experimental validation. The simulation results are based upon both linear and nonlinear vehicle dynamics models and include important effects such as sensor drift and noise, disturbances acting on the vehicle, and model uncertainties. The experimental validation is based on test data from a specially instrumented vehicle driven on a test track. These results indicate that the proposed yaw rate estimation scheme performs well for a wide range of operating conditions and is not difficult to implement.

A Unified Analytical Framework for Ship Domains

2009 ◽  
Vol 62 (4) ◽  
pp. 643-655 ◽  
Author(s):  
Ning Wang ◽  
Xianyao Meng ◽  
Qingyang Xu ◽  
Zuwen Wang
Keyword(s):  
Collision Avoidance ◽  
Traffic Engineering ◽  
Analytical Framework ◽  
Domain Model ◽  
Analytical Models ◽  
Collision Risk ◽  
Marine Traffic ◽  
Different Types ◽  
Domain Models ◽  
Simulation Results

Most of the existing typical ship domains have been comprehensively reviewed and classified. Most of these ship domains are described in a geometrical manner that is difficult to apply to practices and simulations in marine traffic engineering. According to different types of geometrical ship domains, we have proposed mathematical models, based on which a unified analytical framework has been established. It is feasible and practical for the analytical models to be applied to the assessment of navigational safety, collision avoidance and trajectory planning, etc. Finally, some computer simulations and comparative studies of the proposed domain model have been presented and the simulation results show that the uniform analytical framework for ship domains is effective and identical to the original geometrical ones. It should be noted that the analytical domain models could be directly applied in any collision risk, collision avoidance or VTS system while the geometrical ones would be more illustrative but less practical or analytical.

Displacement and Blocking Force Performance of Piezoelectric T-Beam Actuators

2010 ◽  
Author(s):  
Hareesh K. R. Kommepalli ◽  
Kiron Mateti ◽  
Christopher D. Rahn ◽  
Srinivas A. Tadigadapa
Keyword(s):  
Theoretical Prediction ◽  
Cross Section ◽  
Experimental Validation ◽  
Analytical Models ◽  
Out Of Plane ◽  
Cantilevered Beam ◽  
Beam Displacement ◽  
T Beam ◽  
Meso Scale ◽  
Shaped Cross Section

In this paper, we present the experimental validation of the detailed models developed for the flexural motion of piezoelectric T-beam actuators. With a T-shaped cross-section, and bottom and top flange and web electrodes, a cantilevered beam can bend in both in-plane and out-of-plane directions upon actuation. Analytical models predict the tip displacement and blocking force in both directions. Mechanical dicing and flange electrode deposition was used to fabricate six meso-scale T-beam prototypes. The T-beams were experimentally tested for in-plane and out-of-plane displacements, and out-of-plane blocking force. The analytical models closely predict the T-beam displacement and blocking force performance. A nondimensional analytical model predict that all T-beam designs for both in-plane and out-of-plane actuation, regardless of scale, have nondimensional displacement and blocking force equal to nondimensional voltage. The results from experiments are favorably compared with this theoretical prediction.

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