scholarly journals Calculation of Blade Track Height Using an Optical Tracker

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Eric Bechhoefer ◽  
Brian Tucker
Keyword(s):  
Sensitivity Analysis ◽  
Optical Sensor ◽  
Ride Quality ◽  
Solution Strategy ◽  
Flight Testing ◽  
Height Estimate

Rotor Track and Balance (RTB) is a necessary maintenance action to improve aircraft ride quality and decrease fatigue for both the aircrew and helicopter equipment. While there have been a number of papers discussing the solution strategy for optimizing both blade track split and vibration, little work has been reported on how to calculate blade track by using an optical sensor. This paper will discuss the formulation of the blade track height estimate based on optical tracker measurements from flight-testing. Furthermore, the article will include a sensitivity analysis to define the blade track height error. Finally, contending solutions strategies are tested by comparing the results between two pulse and three pulse optical trackers.

Deadbands Tell No Tails: X-56A Dynamic Actuation Requirements

2020 ◽  
Author(s):  
Alexander M. Pankonien ◽  
Peter M. Suh ◽  
Jacob R. Schaefer ◽  
Robert M. Mitchell
Keyword(s):  
State Of The Art ◽  
Ride Quality ◽  
Flight Testing ◽  
Nonlinear Simulation ◽  
The Past ◽  
Actuation System ◽  
Testing Data ◽  
Aircraft Performance ◽  
Number Of Cycles ◽  
Significant Effort

Abstract Following significant effort over the past several years by AFRL and NASA, the X-56A flight vehicle has proven to be a useful platform for exploring controllers and distributed actuation on a flexible, swept flying-wing. The program sought to advance the state of the art in airworthiness for vehicles encountering flutter, leading to relaxed design constraints that could drastically decrease structural weight and improve aircraft performance. Specifically, the vehicle was designed to encounter different forms of flutter: body-freedom flutter, and wing-bending torsion flutter, making it an ideal candidate for identifying dynamic actuation challenges. Flight testing led to fundamental observations by controller designers about the actuation needs for such a vehicle. Namely, the small inherent actuator deadband led to significant constant-amplitude limit cycle oscillations of the system during post-flutter controlled flight. This work captures these observations by exploring theoretical changes in the actuators via a nonlinear simulation tuned with flight testing data and shows that a 60% reduction in actuator deadband can improve ride quality by nearly 50%. The results are combined into a set of actuation challenges for the adaptive structures community at large, including precise actuation for a large number of cycles over multiple timescales, with a relevant baseline described by original actuation system.

Analysis and Enhancement of Hybrid Skyhook-Groundhook Semi-Active Suspension Controller for Optimal Performance

2017 ◽  
Author(s):  
Omid Ghasemalizadeh ◽  
Saied Taheri ◽  
Amandeep Singh ◽  
Kanwar B. Singh
Keyword(s):  
Sensitivity Analysis ◽  
Control System ◽  
Real Time ◽  
Active Suspension ◽  
Ride Quality ◽  
Suspension Systems ◽  
Optimum Point ◽  
Active Suspension Systems ◽  
Novel Approach ◽  
Input Parameters

This study presents a novel approach to analyze and fine-tune control system algorithms for semi-active suspension systems. In the case off road vehicles (example military vehicles), the ability of the suspension control system to keep the vehicle ride quality in an acceptable range is of paramount importance. Though limited in their intervention, semi-active suspensions are less expensive to design and consume far less energy in comparison to active suspension systems. In recent times, research in semi-active suspension systems has continued to advance with respect to their capabilities, narrowing the gap between semi-active and fully active suspension systems. This study investigates the usage of a semi-active suspension with a skyhook-groundhook hybrid controller. As a first step, sensitivity analysis of the controller performance to varying vehicle/road input parameters is conducted. This approach utilizes sensitivity analysis and one-factor-at-a-time method (OFAT) to find and reach the optimum point of vehicle suspension settings. Furthermore, real-time tuning of the mentioned controller is studied. Real-time tuning will help keep the ride quality of the vehicle close to its optimum point even during situations when the vehicle/road input parameters change. A quarter-car model is used for all the simulations and sensitivity analysis.

Ride Quality Flight Testing

1978 ◽  
Vol 1 (2) ◽  
pp. 159-160 ◽  
Author(s):  
Robert L. Swaim
Keyword(s):  
Ride Quality ◽  
Flight Testing

The Solution Strategy as an Indicator of the Developmental Stage of Preschool Children’s Mental-Rotation Ability

2010 ◽  
Vol 31 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Claudia Quaiser-Pohl ◽  
Anna M. Rohe ◽  
Tobias Amberger
Keyword(s):  
Preschool Children ◽  
Mental Rotation ◽  
Latent Class ◽  
Preschool Age ◽  
Stage Model ◽  
Solution Strategy ◽  
Thinking Aloud ◽  
Transition Analysis ◽  
Solution Strategies ◽  
Close Relationship

The solution strategies of preschool children solving mental-rotation tasks were analyzed in two studies. In the first study n = 111 preschool children had to demonstrate their solution strategy in the Picture Rotation Test (PRT) items by thinking aloud; seven different strategies were identified. In the second study these strategies were confirmed by latent class analysis (LCA) with the PRT data of n = 565 preschool children. In addition, a close relationship was found between the solution strategy and children’s age. Results point to a stage model for the development of mental-rotation ability as measured by the PRT, going from inappropriate strategies like guessing or comparing details, to semiappropriate approaches like choosing the stimulus with the smallest angle discrepancy, to a holistic or analytic strategy. A latent transition analysis (LTA) revealed that the ability to mentally rotate objects can be influenced by training in the preschool age.

On the Robustness of Solution Strategy Classifications

2010 ◽  
Vol 31 (2) ◽  
pp. 68-73 ◽  
Author(s):  
María José Contreras ◽  
Víctor J. Rubio ◽  
Daniel Peña ◽  
José Santacreu
Keyword(s):  
Individual Differences ◽  
Study Strategies ◽  
Solution Strategy ◽  
Specific Test ◽  
Spatial Tasks ◽  
The Stability ◽  
Strategy Changes ◽  
Over Time

Individual differences in performance when solving spatial tasks can be partly explained by differences in the strategies used. Two main difficulties arise when studying such strategies: the identification of the strategy itself and the stability of the strategy over time. In the present study strategies were separated into three categories: segmented (analytic), holistic-feedback dependent, and holistic-planned, according to the procedure described by Peña, Contreras, Shih, and Santacreu (2008) . A group of individuals were evaluated twice on a 1-year test-retest basis. During the 1-year interval between tests, the participants were not able to prepare for the specific test used in this study or similar ones. It was found that 60% of the individuals kept the same strategy throughout the tests. When strategy changes did occur, they were usually due to a better strategy. These results prove the robustness of using strategy-based procedures for studying individual differences in spatial tasks.

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