Stability and Computer Simulation of Trailed Implement under Different Operating Conditions

2016 ◽  
Vol 826 ◽  
pp. 61-65
Author(s):  
Nidal H. Abu-Hamdeh
Keyword(s):  
Normal Component ◽  
Slope Angle ◽  
Operating Conditions ◽  
Vehicle Stability ◽  
Road Vehicle ◽  
Sloping Ground ◽  
Stability And Control ◽  
Maximum Value ◽  
And Control ◽  
Drawbar Pull

The mechanics of a trailer system moving up and down sloping ground under different operating conditions was theoretically simulated. A computer program was developed to analyze the system to predict the effect of both the trailer loading weight and the slope angle on the off-road vehicle stability, traction ability, and drawbar loading. The results of this analysis showed that the off-road vehicle becomes unstable when towing a 3750 kg trailer uphill at 28° slope angle. Insufficient traction occurred at slope angles ranging from 15° to 18° corresponding to trailer weight of 3750 to 750 kg. The parallel component of drawbar pull reached a maximum value of (17318) N when the trailer was pushing the off-road vehicle downhill at 30° slope angle. The normal component (normal to the tractive surface) showed similar maximum values for both uphill and downhill motions of the system. The use of computer analysis in this study provided a significant improvement in predicting the effect of different parameters on stability and control of off-road vehicle-trailer combination on sloping ground.Keywords: Stability, Traction, Sloping ground, Drawbar.

scholarly journals Computer simulation of stability and control of tractor-trailed implement combinations under different operating conditions

Bragantia ◽  
2004 ◽  
Vol 63 (1) ◽  
pp. 149-162 ◽  
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Hamid F. Al-Jalil
Keyword(s):  
Normal Component ◽  
Slope Angle ◽  
Operating Conditions ◽  
Uniform Motion ◽  
Sloping Ground ◽  
Stability And Control ◽  
Parallel Component ◽  
Maximum Value ◽  
And Control ◽  
Drawbar Pull

The mechanics of a tractor-trailer system moving up and down sloping ground under different operating conditions was theoretically simulated. A computer program was developed to analyze the system to predict the effect of both the trailer loading weight and the slope angle on the tractor stability, traction ability, and drawbar loading. The program was used to analyze a tractor-trailer system moving at uniform motion up and downhill. The results of this analysis showed that the tractor becomes unstable when towing a 3750 kg trailer uphill at 28° slope angle. Insufficient traction occurred at slope angles ranging from 15° to 18° corresponding to trailer weight of 3750 to 750 kg. The parallel component of drawbar pull reached a maximum value of 17318 N when the trailer was pushing the tractor downhill at 30° slope angle. The normal component (normal to the tractive surface) showed similar maximum values for both uphill and downhill motions of the system. The use of computer analysis in this study provided a significant improvement in predicting the effect of different parameters on stability and control of tractor-trailer combination on sloping ground.

scholarly journals Designing Stipulated Gains of Aircraft Stability and Control Augmentation Systems for Semiglobal Trajectories Tracking

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed Mostafa Y. B. Elshabasy ◽  
Yongki Yoon ◽  
Ashraf Omran
Keyword(s):  
Control Method ◽  
Simple Procedure ◽  
Operating Conditions ◽  
Stability And Control ◽  
Wide Range ◽  
Flight Envelope ◽  
The Stability ◽  
Classical Control ◽  
And Control ◽  
Aircraft Stability And Control

The main objective of the current investigation is to provide a simple procedure to select the controller gains for an aircraft with a largely wide complex flight envelope with different source of nonlinearities. The stability and control gains are optimally devised using genetic algorithm. Thus, the gains are tuned based on the information of a single designed mission. This mission is assigned to cover a wide range of the aircraft’s flight envelope. For more validation, the resultant controller gains were tested for many off-designed missions and different operating conditions such as mass and aerodynamic variations. The results show the capability of the proposed procedure to design a semiglobal robust stability and control augmentation system for a highly maneuverable aircraft such as F-16. Unlike the gain scheduling and other control design methodologies, the proposed technique provides a semi-global single set of gains for both aircraft stability and control augmentation systems. This reduces the implementation efforts. The proposed methodology is superior to the classical control method which rigorously requires the linearization of the nonlinear aircraft model of the investigated highly maneuverable aircraft and eliminating the sources of nonlinearities mentioned above.

Stability and Control of a Thermoacoustic Device: The Rijke’s Tube

2014 ◽  
Author(s):  
Nejat Olgac ◽  
Umut Zalluhoglu ◽  
Ayhan S. Kammer
Keyword(s):  
Linear Time ◽  
Operating Conditions ◽  
Delayed Systems ◽  
Thermoacoustic Instability ◽  
Linear Time Invariant ◽  
Stability And Control ◽  
Characteristic Roots ◽  
Simplifying Assumptions ◽  
Prediction And Control ◽  
And Control

This study presents an intersection of two seemingly separate areas of research frontiers, “prediction and control of thermoacoustic instability” and “stability analysis of neutral-class linear-time-invariant (LTI) and time-delayed systems (TDS)”. The former is a coveted capability which has been elusive to the scientific community over 1½ centuries. Analytical capabilities have been limited due to the complex physics invoking the “combustion” phenomenon. Most available results rely on accumulated empirical knowledge. In this paper we consider a benchmark combustion test platform, which is known as Rijke’s tube. Its representation is simplified to an LTI neutral TDS, stability of which is assessed using a recent mathematical paradigm called the Cluster Treatment of Characteristic Roots (CTCR). CTCR provides a unique non-conservative and exhaustive stability declaration for a Rijke’s tube within the space of its parameters, naturally, under some simplifying assumptions. For those operating conditions which induce instability, we also propose a conventional and simple control strategy which can recover stability. This method is also analyzed using the CTCR paradigm for the first time.

Rotor Blade Wake Flutter—A Comparison of Theory and Experiment

1976 ◽  
Vol 21 (2) ◽  
pp. 32-43 ◽  
Author(s):  
William D. Anderson ◽  
George A. Watts
Keyword(s):  
High Frequency ◽  
Mode Coupling ◽  
Unsteady Aerodynamics ◽  
Specific Region ◽  
Vehicle Stability ◽  
Main Rotor ◽  
Stability And Control ◽  
Design Changes ◽  
Bladed Rotor ◽  
And Control

During early whirl testing of the hingeless main rotor of the AH‐56A Cheyenne helicopter, a high‐frequency (7P), highly coupled, flap‐torsion‐inplane flutter occurred at rotor overspeed at a condition of near zero lift at the rotor tips. The flutter disappeared at higher and lower values of rotor lift rather than being nearly lift independent as had been predicted by quasisteady aerodynamic theory. Wake flutter was suspected and coroborated by subsequent analysis. This discussion covers the theoretical flutter analyses and the effects on flutter of design changes made both to eliminate the flutter and to improve vehicle stability and control. A theoretical analysis employing quasi‐steady aerodynamics was the basis for predicting the complicated reactionless interblade mode shape and frequency, but not the lift level of instability. The flutter stability analysis was then amended to include the effects of previous blade passage wakes and interblade mode coupling, in the four‐bladed rotor, on unsteady aerodynamics and the new analysis results agreed very well with the experimental flutter. The flutter was shown to occur in the specific region of lift near zero, being stable at higher and lower levels, and at a critical overspeed rpm with stability reappearing with increase of rpm above the critical.

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