http://hdl.handle.net/2027.42/90422 Wed, 19 Jun 2013 22:17:48 GMT 2013-06-19T22:17:48Z http://hdl.handle.net/2027.42/98080 VESIM - Automotive Research Center (ARC) VEhicle SIMulation - Hybrid Electric Ersal, Tulga; Stein, Jeffrey; Filipi, Zoran; Peng, Huei; Assanis, Dennis; Fathy, Hosam; Louca, Lucas; et. al. The hybrid electric vehicle simulation tool (HE-VESIM) was developed at the Automotive Research Center of the University of Michigan to study the potential fuel economy and emission benefits of the parallel hybrid propulsion system for a medium truck. This is a feed-forward simulation with dynamic equations of vehicle sub-system modules. A power management control algorithm is based on mimicking the behaviour of a dynamic-programming optimisation scheme. VESIM has been used in numerous ARC research projects. References: Assanis, D. N., Filipi, Z. S., Gravante, S., Grohnke, D., Gui, X., Louca, L. S., Rideout, G. D., Stein, J. L., and Wang, Y., 2000, "Validation and Use of Simulink Integrated, High Fidelity, Engine-in-Vehicle Simulation of the International Class Vi Truck", 2000 SAE Transactions – Journal of Engines. ; C.-C. Lin, Z. Filipi, L. Louca, H. Peng, D. Assanis, J. Stein, "Modelling and control of a medium-duty hybrid electric truck," Int. J. of Heavy Vehicle Systems, 2004 Vol.11, No.3/4, pp.349 - 371, doi:10.1504/IJHVS.2004.005455 ; Ersal, T., Brudnak, M., Salvi, A., Stein, J. L., Filipi, Z., and Fathy, H. K., 2011, "Development and Model-Based Transparency Analysis of an Internet-Distributed Hardware-in-the-Loop Simulation Platform", Mechatronics, 21(1), pp. 22-29. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/2027.42/98080 2012-01-01T00:00:00Z http://hdl.handle.net/2027.42/97341 An Electro-thermal Model for the A123 26650 LiFePO4 Battery Lin, Xinfan; Perez, Hector; Siegel, Jason; Stefanopoulou, Anna An electro-thermal model consisting of an equivalent-circuit electrical model and a two-state lumped thermal model is constructed for an A123 26650 LiFePO4 battery. The electrical and the thermal sub-models are coupled through heat generation and temperature dependency of the electrical parameters. The 5-state model captures the state of charge, voltage, surface temperature, and core temperature of a battery and is computationally efficient. The electrical and the thermal models are parameterized by pulse-relaxation and drive-cycle tests separately, where the electrical parameters are identified as dependent on temperature, SOC and current direction. Fri, 19 Apr 2013 00:00:00 GMT http://hdl.handle.net/2027.42/97341 2013-04-19T00:00:00Z http://hdl.handle.net/2027.42/93779 Fast Analytical Models of Wheel-Soil Interactions Jia, Zhenzhong; Peng, Huei Hazardous terrains pose a crucial challenge to mobile robots. To operate safely and efficiently, it is necessary to detect the terrain type and modify operation strategies in real-time. Fast analytical models of wheeled locomotion on deformable terrains are thus important. Based on classic terramechanics, a closed-form wheel–soil interaction model was derived by quadratic approximation of stresses along the wheel– soil interface. The bulldozing resistance and the effects of grousers were also added for more accurate prediction of wheel contact forces. A non-iterative method was proposed to estimate the entry angle, by using approximated vertical pressure acting on the wheels. The computational efficiency was improved by avoiding traditional recursive search. Realtime computation of the wheel contact forces is achieved by the terramechanics-based formula (TBF), which was developed by integrating the wheel–soil interaction model and the entry angle estimator. In addition, an automotive inspired approach was used to integrate the TBF and the simplified vehicle dynamics model for fast simulation of mobile robots. Stability problems in numerical simulation could be avoided by this method. The above models were verified by comparing simulation results and experiment data, including single-wheel experiments and full-vehicle experiments. The basic principle of the fast analytical models and some related demos (mainly experimental verifications) are explained (in great detail) in "Fast Analytical Models of Wheeled Locomotion in Deformable Terrain for Mobile Robots", Zhenzhong Jia, William Smith and Huei Peng, Robotica, FirstView Articles, October 2012, pp 1-19 DOI: http://dx.doi.org/10.1017/S0263574712000069 . It is highly recommended to read the paper carefully before you getting started with the source code and demos. Thu, 04 Oct 2012 00:00:00 GMT http://hdl.handle.net/2027.42/93779 2012-10-04T00:00:00Z http://hdl.handle.net/2027.42/92728 Design tool for small off road unmanned wheeled ground vehicles Smith, William; Peng, Huei Small unmanned ground vehicles (SUGVs) are used more than ever before in fields ranging from planetary exploration to combat. The success of these vehi-cles depends largely on their energy system performance. In order to maximize the effectiveness of SUGVs and their mission success rate, energy system per-formance must be considered in the original design of the vehicle. For this rea-son an early-stage design tool for off-road skid-steering wheeled SUGVs was developed. The tool provides the user immediate feedback regarding the effect of vehicle and mission parameters on the system’s feasibility and efficiency. The design tool uses the fundamentals of energy conservation, component scal-ing laws, and the theory of terramechanics to determine system feasibility over a variety of operating conditions. This step can eliminate designs which would fail due to insufficient tractive force or energy supply, for example. Further analysis examines the tradeoff between any two vehicle parameters on system performance. In particular, this step is useful for analyzing the interdependence of motor size and transmission ratio on system feasibility and efficiency. Final-ly, the tool can quickly optimize both design and control for a predetermined mission (distance, elevation profile, soil type). Given a range of vehicle pa-rameter values, all design combinations are compared to find the optimal solu-tion using a predefined velocity profile. Then, using the optimal vehicle design, the velocity profile is treated as a control parameter and optimized for the mis-sion while maintaining total travel time. This process iterates until the solution converges. The design tool can help eliminate poor vehicle designs early in the process, lead to more robust designs capable of performing in a variety of oper-ating conditions, and provide insight into the benefits of autonomous operation through flexibility in vehicle speed. The basic principle and case study are explained in the conference paper “Development of a Design Tool for Small Off-Road Unmanned Wheeled Ground Vehicles: A Case Study”, which appeared in AUVSI Unmanned Systems North America 2011. It is recommended to read the paper before you getting started with the source code. Mon, 02 Apr 2012 00:00:00 GMT http://hdl.handle.net/2027.42/92728 2012-04-02T00:00:00Z