ARC Collaborative Research Seminar Series
Winter 2016

ARC seminars are free and open to the general public. Center members can download the presentation files on our password-access online portal iARC. Non-ARC attendees please email arc-event-inquiries@umich.edu with your requests.

Parking & directions inquires: Contact Kathie Wolney (kathian@umich.edu) by 2:00 p.m. the day before the seminar

Remote attendance via tele/video conference: Contact William Lim (choonhun@umich.edu)

Refreshments will be served 9:15-9:30am. The talks will begin at 9:30 a.m. sharp.
Venue: 1180 Duderstadt Center


January 22, Friday (9:15a.m. - 11a.m.)
University of Michigan, UM North Campus, Phoenix Memorial Lab. 2000A

Thrust Area 5: Vehicle System Integration, Optimization, and Robustness

1. Intelligent Decisions in Uncertain Terrain
Dr. Kira Barton, Asst. Prof. of Mechanical Engineering, University of Michigan

        Technology advancements in sensing, data management and control continue to push the envelope for intelligent vehicle systems. Coordinating a collection of unmanned vehicles is a task that is particularly well suited for intelligence; requiring new advancements in terrain management and cooperative control. While these research areas are traditionally handled separately, the integration of terrain management into a cooperative framework is essential to maintaining military dominance in this area in the future. Terrain management is comprised of terrain classification and characterization, as well as localization. Terrain classification aims at associating terrains with one of a few predefined categories, such as gravel, sand, or asphalt. Terrain characterization aims at determining key parameters of the terrain that affect its ability to support vehicular traffic. Such properties are collectively called “trafficability.” Besides terrain information, autonomous operations require location awareness. Although GPS is capable of providing 3D locations with high accuracies, in many environments and for strategic operations, the availability of GPS is not guaranteed. Cooperative control and optimization can be accomplished through a variety of approaches. Learning algorithms (e.g. reinforcement learning, machine learning, iterative learning control) as well as stochastic optimization algorithms (amongst others) have all been used to understand patterns and determine optimized decisions (or control inputs) to achieve a cooperative task with multiple agents. In this talk, we will discuss current research thrusts focused on terrain management and cooperative control towards the vision of intelligent vehicle systems.

2. Distributed Coordination and Coverage Control for Multi-Agent Systems in Constrained Environments
Dr. Dimitra Panagou, Asst. Prof. of Aerospace Engineering, University of Michigan

        Surveillance and situational awareness in civilian and military environments are nowadays pursued using squads of autonomous unmanned vehicles and robots (ground, marine, aerial, space) and sensor networks. Planning, coordination and control for such complex systems is challenging due to non-trivial agent (vehicle, robot) dynamics, restrictions in onboard sensing, computation and communication among agents, the number of agents in the squad, and the uncertain, or even hostile, operational environment. The mission is accomplished as long as agents remain safe, sensing and communication remain effective, and after sufficient amount of information has been gathered about the environment, despite potential agent failures or external attacks. In this talk we will present our recent results on the safe, semi- cooperative coordination among multiple agents, as well as the dynamic coverage control (information gathering) for multi-agent systems in obstacle environments, under sensing and communication constraints and ideas for future research using teams of ground and aerial unmanned vehicles. This work will lay the foundation for a research effort funded by G&SP Survivability Community of Interest.


February 5, Friday (9:15a.m. - 11a.m.)
University of Michigan, UM North Campus, Duderstadt Center, room 1180

Thrust Area 3: High Performance Structures and Materials

Projects presenting:
1. Development of Simulation Model Validation Framework for RBDO (project link)
Min-Yeong Moon, K.K. Choi (PI), Hyunkyoo Cho and Nicholas Gaul, Mechanical & Industrial Engineering, University of Iowa
David Lamb, David Gorsich US Army TARDEC

        Reliability-based design optimization (RBDO) has been carried out under the assumption that the simulation model represents the real physics accurately. However, the assumption may not hold because the model is often biased. Therefore, model validation, which corrects model bias, should be integrated in the RBDO process to obtain the optimized product that satisfies the target reliability. However, the experimental data, which is used for the model validation, is usually insufficient due to cost and time. The uncertainty induced by insufficient data forces engineers to lose confidence on the optimized design even with the validated model. Therefore, we propose an RBDO process using confidence-based model validation to achieve conservative design to compensate the uncertainty. It is found that that the RBDO process with model bias correction becomes a moving-target problem. To resolve the issue, we propose a practical RBDO procedure given insufficient experimental data. We demonstrate that the proposed model validation and RBDO provides conservative design.

2. Light Weight Vehicle Structures that Absorb and Direct Destructive Energy Away from the Occupant (project link)
Weiran Jiang (presenter), Nick Vlahopoulos (PI), Naval Architecture and Marine Engineering, University of Michigan

        Assessing the dynamic performance of multilayer panels subjected to impulsive loading is of interest for identifying configurations that either absorb energy or transmit the energy in the transverse directions, thereby mitigating the through-thickness energy propagation. A reduced-order modeling approach is presented for rapidly evaluating the structural dynamic performance of a large number of alternative panel designs. The new approach is based on the reverberation matrix method (RMM) with the theory of generalized rays for fast analysis of the structural dynamic characteristics of multilayer plates. The dynamic response of the plate is calculated by employing the generalized ray theory and an inverse Fourier Transformation. Free response results obtained by the new approach are shown to have good agreement with those obtained by a spectral finite element analysis. Then, different panel configurations are ranked by evaluating the dynamic response with the new reduced-order model. These forced response results are validated successfully by comparison to the ranking obtained through much more computationally expensive Nastran simulations.


March 11, Friday (9:15a.m. - 11a.m.)
University of Michigan, UM North Campus, Duderstadt Center, room 1180

Thrust Area 4: Advanced and Hybrid Powertrains

Projects presenting:
1. Towards Robust, High Capacity Insertion Compounds (project link)
Krista Hawthorne, Ryan Franck, Siu on Tung, Levi Thompson, University of Michigan
James Mainero, Yi Ding, U.S. Army RDECOM-TARDEC

        Vehicles, both civilian and military, require more energy dense and stable batteries as demands for longer range and lower cost increase and on-board technologies become more complex. Layered materials are most promising, however, layered cathodes in lithium ion batteries typically suffer from capacity fade due to poor thermal stability and mechanical fracture due to repeated insertion of lithium ions. We hypothesized that incorporation of pillaring agents between the layers would increase cycling and thermal stability by supporting the layers during cycling. In addition we expected that pre-lithiating these materials would increase stability. This presentation will describe our progress in characterizing the electrochemical, thermal, and mechanical properties of pillared and pre-lithiated materials. We also will present preliminary results for a magnesium ion battery employing the plllared cathode materials.

2. Energy-Conscious Warm-up of Li-ion Cells from Sub-zero Temperatures (project link)
Shankar Mohan, Jason Siegel and Anna G. Stefanopoulou, University of Michigan
Yi Ding, Matt Castanier, U.S. Army TARDEC
Dyche Anderson, Ford Motor Co
.

        The power availability of Lithium-ion cells is limited due to their resistance increase at sub-zero temperatures. One way to improve their performance in these adverse operation conditions is to proactively heat them using as little of the energy stored within by using an energy-minimization strategy. In addition, should warm-up be possible, it is desirable to know a priori, the minimum energy required to meet objectives so that the supervisory controller that manages power-flow can take appropriate action. In this presentation, we consider the scenario in which a battery powers a heater that is capable of assisting in battery warm-up though a convective heat transfer medium, and solve for the optimal warm-up policy. It is shown that the optimal control policy appears to consist of constant current (CC), constant Voltage (CV) and rest phases. To identify the minimum required remaining state-of-charge for warm-up, a convex reachability verification problem is formulated and solved using sums-of-squares programming. Using this approach, a map of the minimum energy required for warm-up is derived as a function of the atmospheric temperature, desired terminal temperature and the initial temperature of the pack.


April 29, Friday (9:15a.m. - 11a.m.)
University of Michigan, UM North Campus, Duderstadt Center, room 1180

Thrust Area 1: Dynamics and Control of Vehicles

Projects presenting:
1. Flexible Multibody Dynamics Approach for Tire Dynamics Simulations (project link)
Hiroyuki Sugiyama (PI), Hiroki Yamashita (The University of Iowa), Paramsothy Jayakumar (U.S. Army TARDEC), Ryoji Hanada (Yokohama Rubber), SeeChew Soon (Caterpillar Inc.)

        A physics-based high-fidelity computational model for tire and soil interaction is essential to demonstrate mobility capability in various operational military scenarios on deformable terrains. Use of existing finite element tire models requires co-simulation techniques for integration with multibody vehicle simulation models, leading to computationally intensive procedure due to small macro step size needed to ensure numerical stability and energy balance of the entire vehicle model. In this study, a physics-based flexible tire model that can be fully integrated into multibody dynamics computer algorithms is proposed using the laminated composite shell element based on the absolute nodal coordinate formulation and the distributed parameter LuGre tire friction model for transient vehicle maneuvers. The tire model developed is validated against test data. Furthermore, a continuum soil model using multiplicative finite strain plasticity theory is integrated with the flexible tire model for use in physics-based off-road mobility simulation.

2. Improving Energy Efficiency and Mobility of Connected Fleets via Route Preview and Cooperative Control (project link)
Ardalan Vahidi, Judhajit Roy, Nianfeng Wan, Angshuman Goswami (Clemson University), Chen Zhang (Ford Motor Corp.), Paramsothy Jayakumar (U.S. Army TARDEC)

        Improvements in fleet energy efficiency and safety are of paramount importance to the Army. A novel path-planning algorithm as part of a decision support tool for off-road scenarios is presented here. The algorithm incorporates a-priori knowledge of the low resolution soil and elevation information. The proposed hierarchical path-planning algorithm distributes the computational cost to find the optimal path over a large terrain. A dynamic programming (DP) method generates the globally optimal path approximation based on soil condition and low resolution elevation information. The optimal cost-to-go from each grid cell to the destination is calculated by back-stepping from the target and stored. A model-predictive algorithm finds the locally optimal path over moving radial horizon using the cost-to-go map and high resolution elevation map.​


ARC members can download the presentation files on our password-access online portal iARC.
Non-ARC members please email arcweb-info@umich.edu with your requests.