Automated Design Synthesis of Articulated Heavy Vehicles With Active Trailer Steering Systems

2010 ◽  
Author(s):  
Md Manjurul Islam ◽  
Yuping He ◽  
Timothy D. Webster
Keyword(s):  
Design Method ◽  
Automated Design ◽  
Driver Model ◽  
Lateral Stability ◽  
Heavy Vehicles ◽  
Design Synthesis ◽  
Vehicle Performance ◽  
High Speeds ◽  
Design Variables ◽  
Low Speeds

This paper presents an automated design synthesis approach for articulated heavy vehicles (AHVs) with active trailer steering (ATS) systems. AHVs have poor maneuverability when traveling at low speeds. Moreover, AHVs exhibit unstable motion modes at high speeds. To address the problem of maneuverability, ‘passive’ trailer steering systems have been developed. These systems improve low-speed performance, but feature with low lateral stability at high speeds. Some ATS systems have been proposed to improve highspeed lateral stability. However, these systems typically degrade maneuverability when applied at low speeds. To tackle this conflicting design problem, a systematic method is proposed for the design of AHVs with ATS systems. This new design method has the following features: the optimal active design variables of the ATS systems and the optimal passive design variables of the vehicle are identified in a single design loop; in the design process, to evaluate the vehicle performance measures, a driver model is introduced and it ‘drives’ the vehicle model based on the well-defined testing specifications. Through the design optimization of an ATS system for an AHV with a tractor and a full trailer, this single design loop (SDL) method is compared against a published two design loop (TDL) method. The benchmark investigation shows that the former can determine better trade-off design solutions than those derived by the latter. This SDL method provides an effective approach to automatically implement the design synthesis of AHVs with ATS systems.

An Automated Design Method for Active Trailer Steering Systems of Articulated Heavy Vehicles

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Yuping He ◽  
Md. Manjurul Islam
Keyword(s):  
Design Method ◽  
Bilevel Optimization ◽  
Automated Design ◽  
Driver Model ◽  
Design Decision ◽  
Design Framework ◽  
Heavy Vehicles ◽  
Trade Off ◽  
Vehicle Simulation ◽  
Loop Design

An important design decision for active trailer steering (ATS) systems for articulated heavy vehicles (AHVs) is the trade-off between maneuverability and lateral stability. This paper presents an automated design method for this trade-off. The proposed method has the following features: (1) a design framework for bilevel optimization of ATS systems is formulated; (2) design variables of ATS controllers and trailers are optimized simultaneously; (3) two controllers are designed for the ATS system for improving stability and enhancing maneuverability, respectively; and (4) a driver model is introduced in the virtual vehicle simulation for closed-loop testing maneuvers. The design framework allows automation of vehicle modeling, controller construction, performance evaluation, and design variable selection, and all required design processes are implemented in a single loop. The proposed method is compared to a previously published two-loop design method, showing that the new approach can effectively identify desired variables and predict performance envelopes.

An Optimum Design of the Transverse Pressure Contour Slider for Enhanced Flying Characteristics

1997 ◽  
Vol 119 (3) ◽  
pp. 520-524 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Optimum Design ◽  
Design Method ◽  
Optimization Technique ◽  
Flying Height ◽  
Step Width ◽  
Skew Angle ◽  
Sqp Method ◽  
Design Synthesis ◽  
Transverse Pressure ◽  
Design Variables

This paper proposes a design method for determining the configuration of a TPC slider by using an optimization technique in order to meet the desired flying characteristics over the entire recording band. The desired flying characteristics considered in this study are to minimize the variation in flying height from a target value, to maintain the pitch angle as large as possible, to keep the roll angle as small as possible, and to keep the outside rail to fly lower than the inside rail. The design variables selected are left-side step width, pad width, right-side step width, side step depth, front taper height, and pivot offset in the transverse direction of the slider. The sequential quadratic programming (SQP) method in Automated Design Synthesis (ADS) is used to efficiently find the optimum design variables which simultaneously meet all the desired flying characteristics. To validate the suggested design method, a computer program is developed and applied to the configuration design of two TPC slider models positioned by a rotary actuator. The optimum configurations of each slider model are automatically obtained for three different target flying heights with the same predefined skew angle range without any difficulty. This shows the effectiveness of the proposed design method in comparison with the conventional one based on the parametric study.

Optimization Research on Dynamic Balance of Spatial Engine under Limiting Shaking Moment

2009 ◽  
Vol 626-627 ◽  
pp. 693-698
Author(s):  
Yong Yong Zhu ◽  
S.Y. Gao
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
Kinetic Analysis ◽  
Optimization Design ◽  
Design Method ◽  
Dynamic Balance ◽  
Optimized Design ◽  
Design Variables ◽  
The Mathematical Model ◽  
Shaking Moment

Dynamic balance of the spatial engine is researched. By considering the special wobble-plate engine as the model of spatial RRSSC linkages, design variables on the engine structure are confirmed based on the configuration characters and kinetic analysis of wobble-plate engine. In order to control the vibration of the engine frame and to decrease noise caused by the spatial engine, objective function is choosed as the dimensionless combinations of the various shaking forces and moments, the restriction condition of which presents limiting the percent of shaking moment. Then the optimization design is investigated by the mathematical model for dynamic balance. By use of the optimization design method to a type of wobble-plate engine, the optimization process as an example is demonstrated, it shows that the optimized design method benefits to control vibration and noise on the engines and improve the performance practically and theoretically.

scholarly journals A Collision Dynamics Model of a Multi-Level Train

2006 ◽  
Author(s):  
Michelle Priante ◽  
David Tyrell ◽  
Benjamin Perlman
Keyword(s):  
Three Dimensional ◽  
Design Parameters ◽  
Collision Dynamics ◽  
Dynamics Model ◽  
Single Level ◽  
High Speeds ◽  
Front End ◽  
Multi Level ◽  
Low Speeds ◽  
Vertical Accelerations

In train collisions, multi-level rail passenger vehicles can deform in modes that are different from the behavior of single level cars. The deformation in single level cars usually occurs at the front end during a collision. In one particular incident, a cab car buckled laterally near the back end of the car. The buckling of the car caused both lateral and vertical accelerations, which led to unanticipated injuries to the occupants. A three-dimensional collision dynamics model of a multi-level passenger train has been developed to study the influence of multi-level design parameters and possible train configuration variations on the reactions of a multi-level car in a collision. This model can run multiple scenarios of a train collision. This paper investigates two hypotheses that could account for the unexpected mode of deformation. The first hypothesis emphasizes the non-symmetric resistance of a multi-level car to longitudinal loads. The structure is irregular since the stairwells, supports for tanks, and draglinks vary from side to side and end to end. Since one side is less strong, that side can crush more during a collision. The second hypothesis uses characteristics that are nearly symmetric on each side. Initial imperfections in train geometry induce eccentric loads on the vehicles. For both hypotheses, the deformation modes depend on the closing speed of the collision. When the characteristics are non-symmetric, and the load is applied in-line, two modes of deformation are seen. At low speeds, the couplers crush, and the cars saw-tooth buckle. At high speeds, the front end of the cab car crushes, and the cars remain in-line. If an offset load is applied, the back stairwell of the first coach car crushes unevenly, and the cars saw-tooth buckle. For the second hypothesis, the characteristics are symmetric. At low speeds, the couplers crush, and the cars remain in-line. At higher speeds, the front end crushes, and the cars remain in-line. If an offset load is applied to a car with symmetric characteristics, the cars will saw-tooth buckle.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Multivariate design and analysis of aircraft HEX under multiple working conditions within flight envelope

2021 ◽  
pp. 1-18
Author(s):  
Qihang Liu ◽  
G.Q. Xu ◽  
Jie Wen ◽  
Yanchen Fu ◽  
Laihe Zhuang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Design Method ◽  
Structural Parameters ◽  
Optimal Structure ◽  
Clear Correlation ◽  
Pressure Drops ◽  
Design Variables ◽  
Wide Range ◽  
Common Weight

Abstract This paper presents a multi-condition design method for the aircraft heat exchanger (HEX), marking with light weight, compactness and wide range of working conditions. The quasi-traversal genetic algorithm (QT-GA) method is introduced to obtain the optimal values of five structural parameters including the height, the tube diameter, the tube pitch, and the tube rows. The QT-GA method solves the deficiency of the conventional GA in the convergence, and gives a clear correlation between design variables and outputs. Pressure drops, heat transfer and the weight of the HEX are combined in a single objective function of GA in the HEX design, thus the optimal structure of the HEX suitable for all the working conditions can be directly obtained. After optimization, the weight of the HEX is reduced to 2.250 kg, more than 20% lower than a common weight of around 3 kg. Based on the optimal structure, the off-design performance of the HEX is further analyzed. Results show that the extreme working conditions for the heat transfer and the pressure drops are not consistent. It proves the advance of the multi-condition design method over traditional single-condition design method. In general, the proposed QT-GA design method is an efficient way to solve the multi-condition problems related to the aircraft HEX or other energy systems.

The Impact of Sweep Angle on Stepped Planing Hull Performance

2021 ◽  
Author(s):  
Nicholas Husser ◽  
Stefano Brizzolara
Keyword(s):  
Dynamic Stability ◽  
Sweep Angle ◽  
High Speeds ◽  
Free Running ◽  
Low Speeds ◽  
And Performance ◽  
The Impact

In this study the impact of sweep angle on stepped hull resistance, running attitude, and dynamic stability is investigated for a range of planing speeds from ventilation inception (𝐹𝛻≈2) to high planing speeds (𝐹𝛻≈7) using RANS CFD. Potential performance benefits of the step are isolated for three speeds and two displacements using fixed trim simulations. Differences in running attitude and dynamic stability are investigated using free running simulations at the highest speed for a range of LCG locations. Finally, any differences in ventilation inception and performance at low speeds are investigated using fixed trim and heave simulations. The study shows that swept forward steps do not necessarily ventilate earlier than other step designs but do provide resistance reductions at 𝐹𝛻<5 compared to swept aft and unstepped designs. However, at 𝐹𝛻>5, swept forward steps demonstrate significant resistance increases compared to unswept and swept aft steps. At high speeds, swept aft steps provide improved dynamic stability compared to other step designs without a resistance penalty when compared to unswept steps.

Exploring the Design Space Using a Surrogate Model Approach With Digital Human Modeling Simulations

2018 ◽  
Author(s):  
Salman Ahmed ◽  
Mihir Sunil Gawand ◽  
Lukman Irshad ◽  
H. Onan Demirel
Keyword(s):  
Human Factors ◽  
Surrogate Model ◽  
Human Performance ◽  
Design Method ◽  
Human Subjects ◽  
Design Stage ◽  
Digital Human Modeling ◽  
Design Variables ◽  
Human Modeling ◽  
Digital Human

Computational human factors tools are often not fully-integrated during the early phases of product design. Often, conventional ergonomic practices require physical prototypes and human subjects which are costly in terms of finances and time. Ergonomics evaluations executed on physical prototypes has the limitations of increasing the overall rework as more iterations are required to incorporate design changes related to human factors that are found later in the design stage, which affects the overall cost of product development. This paper proposes a design methodology based on Digital Human Modeling (DHM) approach to inform designers about the ergonomics adequacies of products during early stages of design process. This proactive ergonomics approach has the potential to allow designers to identify significant design variables that affect the human performance before full-scale prototypes are built. The design method utilizes a surrogate model that represents human product interaction. Optimizing the surrogate model provides design concepts to optimize human performance. The efficacy of the proposed design method is demonstrated by a cockpit design study.

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