Time filter

Source Type

Kahlbau S.,IAV Automotive Engineering Inc. | Bestle D.,TU Brandenburg
Mechanics Based Design of Structures and Machines | Year: 2013

In general, gearshift is related to change of acceleration due to the changing gear ratio. Modern double-clutch transmissions allow for shaping the acceleration transition by controlling the torques transmitted by the clutches. Thus, the question arises about an optimal transition law for the acceleration. The paper demonstrates that jerk and change of jerk may be considered as major sources of discomfort. Thus, a bi-criterion optimization problem is formulated for finding an optimal acceleration transition and an associated shift control. The problem is solved by analytical and polynomial approaches, and a theoretically optimal solution is shown. The latter is applied to a simple simulation model of a double-clutch transmission to demonstrate its applicability. © 2013 Taylor & Francis Group, LLC. Source

Jiang S.,AandD Technology Inc. | Nutter D.,AandD Technology Inc. | Gullitti A.,IAV Automotive Engineering Inc.
SAE Technical Papers | Year: 2012

To meet the ever increasing requirements in the areas of performance, fuel economy and emission, more and more subsystems and control functions are being added to modern engines. This leads to a quick increase in the number of control parameters and consequently dramatic time and cost increase for engine calibration. To deal with this problem, the automotive industry has turned to model-based calibration for a solution. Model-based calibration is a method that uses modern Design of Experiments (DoE), statistical modeling and optimization techniques to efficiently produce high quality calibrations for engines. There are two major enablers for carrying out this method-fully automated engine control and measurement system, and advanced mathematical tools for DoE, modeling and optimization. This paper presents a case study of adopting this methodology for the determination of optimum steady state calibrations of ignition timing, air-fuel ratio and intake cam phasing for a gasoline engine. ORION automated engine control and measurement system is used for testing data collection. EasyDoE Toolsuite is used for DoE, engine response modeling and control parameter optimization. Major features of these tools are described. Each step in performing this process, including definition of factors and responses, DoE, automatic measurement on engine test bench, creation of engine models of sufficient accuracy, and generation of control maps using optimization techniques, is covered. The results demonstrate that the model-based approach is a well suited method for engine calibration, and the integrated system provides an effective solution for implementing model-based calibration. Copyright © 2012 SAE International. Source

Cheng Y.,Ford Motor Company | Huang Y.,IAV Automotive Engineering Inc.
SAE Technical Papers | Year: 2010

A lean-rich hydrothermal aging was used to study the deactivation of Cu-zeolite SCR catalyst that has enhanced stability. Impact of DOC upstream on the SCR catalyst during the lean-rich aging was also investigated. The L-R hydrothermal aging was conducted with the presence of hydrocarbon, CO and H 2 at different O 2 levels. It was found that the SCR catalyst was active for the oxidation of CO, H 2 and hydrocarbon, resulting in significant exotherm across the catalyst. In addition to hydrothermal aging, reductive aging, especially the presence of H 2 in the aging gas stream without O 2 presence during the L-R aging, might also contribute to the Cu/zeolite SCR catalyst deactivation. The impacts of DOC upstream on Cu/zeolite SCR catalysts depended on the aging temperatures. At lower aging temperature, the uncompleted oxidation of hydrocarbon and CO on the DOC might cause steam reforming and water-gas shift reactions on the DOC to form reductive gas stream. The reductive gas stream might cause extra deactivation on the SCR in addition to the hydrothermal aging. At higher aging temperature, the down stream SCR catalyst seemed to be protected by the upstream DOC due to the completed oxidation of hydrocarbon and CO on the DOC. Copyright © 2010 SAE International. Source

Morales D.O.,Umea University | Westerberg S.,Umea University | La Hera P.X.,Swedish University of Agricultural Sciences | Mettin U.,IAV Automotive Engineering Inc. | And 2 more authors.
Journal of Field Robotics | Year: 2014

Working with forestry machines requires a great deal of training to be sufficiently skilled to operate forestry cranes. In view of this, it would be desirable within the forestry industry to introduce automated motions, such as those seen in robotic arms, to shorten the training time and make the work of the operator easier. Motivated by this fact, we have developed two experimental platforms for testing control systems and motion-planning algorithms in real time. They correspond to a laboratory setup and a commercial version of a hydraulic manipulator used in forwarder machines. The aim of this article is to present the results of this development by providing an overview of our trajectory-planning algorithm and motion-control method, with a subsequent view of the experimental results. For motion control, we design feedback controllers that are able to track reference trajectories based on sensor measurements. Likewise, we provide arguments to design controllers in an open-loop for machines that lack sensing devices. Relying on the tracking efficiency of these controllers, we design time-efficient reference trajectories of motions that correspond to logging tasks. To demonstrate performance, we provide an overview of extensive testing done on these machines. © 2014 Wiley Periodicals, Inc. Source

La Hera P.X.M.,Umea University | Shiriaev A.S.,Umea University | Shiriaev A.S.,Norwegian University of Science and Technology | Freidovich L.B.,Umea University | And 2 more authors.
IEEE Transactions on Robotics | Year: 2013

We consider a benchmark example of a three-link planar biped walker with torso, which is actuated in between the legs. The torso is thought to be kept upright by two identical torsional springs. The mathematical model reflects a three-degree-of-freedom mechanical system with impulse effects, which describe the impacts of the swing leg with the ground, and the aim is to induce stable limit-cycle walking on level ground. The main contribution is a novel systematic trajectory planning procedure for solving the problem of gait synthesis. The key idea is to find a system of ordinary differential equations for the functions describing a synchronization pattern for the time evolution of the generalized coordinates along a periodic motion. These functions, which are known as virtual holonomic constraints, are also used to compute an impulsive linear system that approximates the time evolution of the subset of coordinates that are transverse to the orbit of the continuous part of the periodic solution. This auxiliary system, which is known as transverse linearization, is used to design a nonlinear exponentially orbitally stabilizing feedback controller. The performance of the closed-loop system and its robustness with respect to various perturbations and uncertainties are illustrated via numerical simulations. © 2004-2012 IEEE. Source

Discover hidden collaborations