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Tarasow A.,Clausthal University of Technology | Wachsmuth G.,IAV GmbH | Lemieux J.,IAV Automotive Engineering Inc. | Serway R.,IAV GmbH | Bohn C.,Clausthal University of Technology
Proceedings of the American Control Conference | Year: 2013

Many concepts for controlling automated clutches use the clutch characteristic as the quasi-steady-state model of torque transmission. In this case, the accuracy of the clutch characteristic used has a significant influence on the quality of control that can be achieved and consequently affects criteria as important as comfort, shifting time or component strain during operation. As a result, it is often necessary to identify changes in transmission behavior of the clutch at the earliest possible stage and adjust the clutch characteristic accordingly. Taking a physics-based approach, this paper focuses on modeling clutch characteristics with the intention of using the model within existing control structures. It also presents a method that is used online for identifying constant or time-varying parameters of the characteristic model developed. © 2013 AACC American Automatic Control Council.

La Hera P.X.M.,Umeå University | Shiriaev A.S.,Umeå University | Shiriaev A.S.,Norwegian University of Science and Technology | Freidovich L.B.,Umeå 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.

Schori M.,University of Rostock | Boehme T.J.,IAV Automotive Engineering Inc. | Frank B.,IAV Automotive Engineering Inc. | Schultalbers M.,IAV Automotive Engineering Inc.
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2013

In this paper, an algorithm for solving a nonlinear hybrid optimal control problem for the fuel-optimal operation of a parallel hybrid electric vehicle is proposed. The proposed algorithm is very simple in its application and allows for finding the optimal controls in hybrid drive mode, as well as optimal discrete dynamics. In particular, the discrete decisions gear choice and drive mode are regarded. The algorithm uses an indirect variation of extremals approach based on necessary conditions for hybrid optimality. For better solvability, we accept the fact, that the solution becomes suboptimal, when encountering state constraints. It will be shown that the solution obtained provides a set of valuable information for the definition of the energy management for a given vehicle. The algorithm can be adapted to other configurations of hybrid vehicles and can be used to determine optimal controls on any drive cycle.

Boehme T.J.,IAV Automotive Engineering Inc. | Frank B.,IAV Automotive Engineering Inc. | Schultalbers M.,IAV Automotive Engineering Inc. | Schori M.,University of Rostock | Lampe B.,University of Rostock
SAE Technical Papers | Year: 2013

In this paper optimal control problems for hybrid powertrain vehicles with different drive-modes are considered and solved using numerical techniques. This leads to the formulation of hybrid optimal control problems. The aim is to find optimal controls and optimal switchings between the drive-modes to minimize a cost function resembling fuel consumption. The problem is nonlinear and subject to constraints concerning both controls and state. The techniques include indirect methods as well as direct optimization methods. Efficiency and accuracy are evaluated for all methods using simulation studies. An experimental test on a near mass-production vehicle confirms the usability of the direct optimization approach. Copyright © 2013 SAE International.

Morales D.O.,Umeå University | Westerberg S.,Umeå 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.

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.

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.

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.

Al-Assadi S.,IAV Automotive Engineering Inc.
SAE Technical Papers | Year: 2014

This paper presents another application [1] of using Artificial Neural Networks (ANN) in adaptive tracking control of an electronic throttle system. The ANN learns to model the experimental direct inverse dynamic of the throttle servo system using a multilayer perceptron neural network structure with the dynamic back-propagation algorithm. An off-line training process was used based on an historical set of experimental measurements that covered all operating conditions. This provided sufficient information on the dynamics of the open-loop inverse nonlinear plant model. The identified ANN Direct Inverse Model (ANNDIM) was used as a feed-forward controller combined with an adaptive feed-back gains (PID) controller scheduled [2] at different operating conditions to provide the robustness in tracking control to un-modeled dynamics of the throttle servo system. The un-modeled dynamics are mainly related to the strong nonlinearity functions that may excite the system with external un-measurable disturbances and noise effects. The feed-forward ANNDIM is first used to emulate the inverse dynamics of the DC servo system. However, the variations in nonlinear dynamics of the throttle body during actual operation cause some error in the prediction of the exact inverse dynamic obtained from ANNDIM. Therefore, by adding the feed-back PID adaptive controller term in the control loop will compensate the model mismatches for these un-modeled dynamic variations and improve the overall control performance. Practical implementation results using rapid prototype real-time system testing are provided to illustrate the performance and effectiveness of the proposed method in tracking controls of multiple set-point changes at different operating conditions. Copyright © 2014 SAE International.

Liu C.-S.,IAV Automotive Engineering Inc.
ASME 2010 Dynamic Systems and Control Conference, DSCC2010 | Year: 2010

This paper addresses the problem of simultaneous estimation of unknown state and input for a class of nonlinear systems. Under certain minimum-phase conditions, the unknown states and inputs can be recovered asymptotically with high gain observers. The design of the observer uses the perfect observation scheme such that a restrictive input-output rank condition can be relaxed. It can be shown that the proposed estimation approach of the unknown input is in the form of the integration of estimation error signals. Thanks to the integrator the common issue of measurement noise corruption of the recovered unknown inputs can be significantly reduced. The proposed approach is applied to real-time estimate in-cylinder air charge and exhaust gas recirculation (EGR) flow rate of automotive internal combustion engines which are important factors for tailpipe emission reduction. Copyright © 2010 by ASME.

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