Person:

Zhang, Fumin

Permanent Link

https://hdl.handle.net/1853/71883

Associated Organization(s)

Organizational Unit

School of Electrical and Computer Engineering

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Publication Search Results

Now showing 1 - 8 of 8

An Analytical Model of the CAN Bus for Online Schedulability Test

(Georgia Institute of Technology, 2012-12-04) Shi, Zhenwu ; Zhang, Fumin

Controller area network (CAN) is a prioritybased bus that supports real-time communication. Existing schedulability analysis for the CAN bus is peformed at the design stage, by assuming that all message information is known in advance. However, in pratice, the CAN bus may run in a dynamic environment, where complete specifications may not be available at the design stage and operational requirements may change at system run-time. In this paper, we develop an analytical model that describes the dynamics of message transmission on the CAN bus. Based on this analytical timing model, we then propose an online test that effectively checks the schedulability of the CAN bus, in the presence of online adjustments of message streams. Simulations show that the online test can accurately report the loss of scheduability on the CAN bus.
Intruder Capturing Game on a Topological Map Assisted by Information Networks

(Georgia Institute of Technology, 2011-12) Kim, Jonghoek ; Maxon, Sean ; Egerstedt, Magnus B. ; Zhang, Fumin

Intruder capturing games on a topological map of a workspace with obstacles are investigated. Assuming that a searcher can access the position of any intruder utilizing information networks, we provide theoretical upper bounds for the minimum number of searchers required to capture all intruders on a Voronoi graph. Intruder capturing algorithms are proposed and demonstrated through an online computer game.
Steady three dimensional gliding motion of an underwater glider

(Georgia Institute of Technology, 2011) Zhang, Shaowei ; Yu, Jiancheng ; Zhang, Aiqun ; Zhang, Fumin

Underwater Gliders have found broad applications in ocean sampling. In this paper, the nonlinear dynamic model of the glider developed by the Shenyang Institute of Automation, Chinese Academy of Sciences, is established. Based on this model, we solve for the parameters that characterize steady state spiraling motions of the glider. A set of nonlinear equations are simplified so that a recursive algorithm can be used to find the solutions.
Battery Level Estimation of Mobile Agents Under Communication Constraints

(Georgia Institute of Technology, 2010-06) Kim, Jonghoek ; Zhang, Fumin ; Egerstedt, Magnus B.

Consider a team of mobile agents monitoring large areas, e.g. in the ocean or the atmosphere, with limited sensing resources. Only the leader transmits information to other agents, and the leader has a role to monitor battery levels of all other agents. Every now and then, the leader commands all other agents to move toward or away from the leader with speeds proportional to their battery levels. The leader then simultaneously estimates the battery levels of all other agents from measurements of the relative distances between the leader and other agents. We propose a nonlinear system model that integrates a particle motion model and a dynamic battery model that has demonstrated high accuracy in battery capacity prediction. The extended Kalman filter (EKF) is applied to this nonlinear model to estimate the battery level of each agent. We improve the EKF so that, in addition to gain optimization embedded in the EKF, the motions of agents are controlled to minimize estimation error. Simulation results are presented to demonstrate effectiveness of the proposed method.
An exploration strategy by constructing Voronoi Diagrams with provable completeness

(Georgia Institute of Technology, 2009-12) Kim, Jonghoek ; Zhang, Fumin ; Egerstedt, Magnus B.

We present novel exploration algorithms and a control law that enable the construction of Voronoi diagrams over unknown areas using a single autonomous vehicle equipped with range sensors. Our control law and exploration algorithms are provably complete. The control law uses range measurements to enable tracking Voronoi edges between two obstacles. Exploration algorithms make decisions at vertices of the Voronoi diagram to expand the explored area until a complete Voronoi diagram is constructed in finite time. MATLAB simulation results are provided to demonstrate the effectiveness of both the control law and the exploration algorithms.
Simultaneous Cooperative Exploration and Networking based on Voronoi Diagrams

(Georgia Institute of Technology, 2009-10) Kim, Jonghoek ; Zhang, Fumin ; Egerstedt, Magnus B.

We develop a strategy that enables multiple intelligent vehicles to cooperatively explore complex and dangerous territories. Every vehicle drops communication devices and expands an information network while constructing a topological map based on the Voronoi diagram. As the information network weaved by each vehicle grows, intersections eventually happen so that the networks are shared. This allows for distributed vehicles to share information with other vehicles that have also dropped communication devices. Our exploration algorithms are provably complete under mild technical assumptions. A performance analysis of the algorithms shows that in a bounded workspace, the time spent to complete the exploration decreases in proportion to the number of vehicles employed. The algorithms are demonstrated in simulation.
Simultaneous Cooperative Exploration and Networking Based on Voronoi Diagrams

(Georgia Institute of Technology, 2009) Kim, Jonghoek ; Zhang, Fumin ; Egerstedt, Magnus B.

We develop a strategy that enables multiple intelligent vehicles to cooperatively explore complex territories. Every vehicle deploys communication devices and expands an information network while constructing a topological map based on Voronoi diagrams. As the information network weaved by each vehicle grows, intersections eventually happen so that the topological maps are shared. This allows for distributed vehicles to share information with other vehicles that have also deployed communication devices. Our exploration algorithms are provably complete under mild technical assumptions. A performance analysis of the algorithms shows that in a bounded workspace, the time spent to complete the exploration decreases as the number of vehicles increases. We further provide an analytical formula for this relationship. Time efficiency of the algorithms is demonstrated in MATLAB simulation.
Curve Tracking for Autonomous Vehicles with Rigidly Mounted Range Sensors

(Georgia Institute of Technology, 2008-12) Kim, Jonghoek ; Zhang, Fumin ; Egerstedt, Magnus B.

In this paper, we present a feedback control law to make an autonomous vehicle with rigidly mounted range sensors track a desired curve. In particular, we consider a vehicle which has two range sensors that emit rays perpendicular to the velocity of the vehicle. Under such a sensor configuration, singularities are bound to occur in the feedback control law. Thus, to overcome this, we derive a hybrid strategy of switching between control laws close to the singularity.