Home   Research   Professional Experience   Publications    Education   Multimedia    Contact   Resume (PDF , DOC)

•Distributed Control & Sensing
Distributed control and sensing in the field of physical surface morphing has been an active area of research. Our research concentrates on determining the optimal actuator and sensor placement methods to attain the desired profile of the flexible surface. Issues related to the number of actuators and sensors to be used will also be explored in order to achieve physical surface morphing in 2-D case. Due to the flexible nature of the surface, it cannot be considered as a lumped system. In order to achieve the required task, the system is considered as a distributed parameter system. Distributed fields are harder to reason than lumped parameter models, since the underlying physics imposes severe constraints on controlled actuation. The research would concentrate on controlling and optimizing the physical field using networks of actuators and sensors.

•Localization of Wireless Sensor Networks
A novel approach for relative and absolute localization of wireless sensor nodes using a potential field method is developed. The main idea of our work is to develop relative and absolute localization algorithms for the position estimate of stationary unattended ground sensor (UGS) nodes using a potential field method. A dynamical model is derived for each sensor node to estimate the relative and absolute position estimates under the influence of a certain fictitious virtual force. In the algorithm the sensor nodes do not move physically, but a virtual motion is carried out to generate optimal position estimates. The convergence of the estimator system to a least squares solution is guaranteed using Lyapunov theory. The relative localization algorithm assumes that distance (i.e. range) measurements between UGS nodes are available and for absolute localization algorithm, uninhabited aerial vehicles (UAV) are available with on board GPS such that they have absolute position information together with range measurement information. In the relative localization algorithm the UGS nodes are localized with respect to an internal co-ordinate frame. In absolute localization the UGS nodes are localized with respect to the known absolute position of UAV in the air-ground network. The effectiveness of the control algorithm is highlighted by simulation and  real time implementation results (Relative Localization results & Absolute Localization results).

•Discrete Event Control
Using a patented matrix formulation, a Discrete Event (DE) controller is designed for a manufacturing cell. The DE controller can directly be implemented from standard manufacturing tools such as the Bill of Materials or the assembly tree. The matrices also make it straightforward to actually implement the DE controller for sequencing the jobs and assigning the resources. In order to keep track of the time durations of the jobs and the time required for resource release, we have used the transient Timed Place Petri Net (PN). In this research, we replace this Timed Place PN by adding a new concept, “Virtual Places” in the original PN Structure. This provides a streamlined approach more suitable for actual implementation on a workcell (Intelligent Material Handling Cell (IMH)). The DE controller is implemented on an actual three-robot Intelligent Material Handling (IMH) cell at the Automation and Robotics Research Institute (ARRI) of UT-Arlington. The controller was implemented in LabVIEW/LabWindows (IMH cell implementation).

•Nonlinear Control
      •Controller for Swing-Up and Balance of Single Inverted Pendulum Using SDRE Based Solution--Design of a real-time State Dependent Riccati Equaion (SDRE) based non-linear controller using S-Functions in MATLAB/Simulink. dSPACE was used as the data acquisition hardware interface (implementation).

      •PID control of Ball Balancer--A PID controller is designed and implemented for the ball balancer unit (Balancing result & Tracking result).

                                             (top of page)

• Automation and Robotics Research Institute, Fort Worth, USA

Research Assistant for design and development of algorithms for distributed control and sensing.

• Alcorn State University, MS, USA

Research Associate for development of control system laboratory.

• UTA Department of Electrical Engineering, Arlington, USA

Teaching Assistant for Control System Design Capstone  course, Linear System and Electronics.

• HArjee Foods, Varanasi, India

Project intern for development of a controller for a biscuit manufacturing unit using a PLC.

(top of page)

P. Dang, F.L. Lewis, D. Popa, "Dynamic localization of air-ground wireless sensor networks”, in Advances in Unmanned Aerial Vehicles: State of the art and road to autonomy, ed. K. Valavanis, Springer-Verlag, Berlin, 2007

P. Dang, P. Ballal, F.L. Lewis, D. Popa., "Real Time Relative and Absolute Dynamic Localization of Air-Ground Wireless Sensor Networks", Accepted to the Journal of Intelligent and Robotic Systems, 2007.

P. Dang, F.L. Lewis, H. Stephanou, K. Subbarao, “Optimal Placement of Microactuators for Distributed Control using Neural Networks”, Submitted to the IEEE Transactions of Neural Network, 2007

P. Dang, F.L. Lewis, H. Stephanou, F. Ham, "A Two Stage Neural Network for Expression Classification", Submitted to IEEE SMC part B, 2007

Peer Reviewed Conferences: