Fundamental Advances in Control of Wireless Sensor and Robotic Networks

Sampling algorithms for sensing and control design have experienced renewed interest due to various resource constraints. Efficient sampling schemes are especially relevant for Wireless Sensor and Robotic Networks (WSRN) due to the underlying network constraints. In the final year of this project, a primary research objective was to investigate event-triggered control for designing efficient sampled-data controllers for robotic systems. In the context of robotic systems, the results were motivated by important problems/challenges such as: trajectory tracking, design of output feedback dynamic controllers and design of controllers with low response time for greater agility.

The following results have been obtained in the third year of the project:

1. Event-triggered controller design for trajectory tracking was developed in [1], where a design of a triggering condition for sampled-data implementation of continuous time controllers for tracking an exogenous trajectory was provided.

2. In [2], an algorithm to co-design the event-trigger and the quantizer of emulation based discrete- event controllers was developed.

3. Event-triggered dynamic output feedback control design for LTI systems was investigated in [3,4] for several architectures including the centralized and a decentralized architecture. In each case, the closed loop system was guaranteed to be globally asymptotically stable even while ensuring a positive minimum for the inter-transmission times (that holds globally).

4. In other areas of interest in WSRN, new results have been developed in output synchronization of nonlinear systems [5], control of robotic systems with input-output delays [6], and in connectivity maintenance for robotic networks [7].

References:

1. P. Tallapragada and N. Chopra, "On Event Triggered Trajectory Tracking for Control Affine Nonlinear Systems," In Proceedings of the IEEE Conference on Decision and Control and European Control Conference, Orlando FL, Dec. 12-15, 2011, pp. 5377 - 5382

2. P. Tallapragada and N. Chopra, "On Co-design of Event-Trigger and Quantizer for Emulation Based Control," In Proceedings of American Control Conference, Montreal, June 27-29 2012, pp. 3772 - 3777.

3. P. Tallapragada and N. Chopra, "Event-Triggered Dynamic Output Feedback Control for LTI Systems," In Proceedings of IEEE Conference on Decision and Control, Mauii Hawaii, Dec. 10-13 2012, To Appear.

4. P. Tallapragada and N. Chopra, "Event-Triggered Decentralized Dynamic Output Feedback Control for LTI Systems," In Proceedings of IFAC Workshop on Distributed Estimation and Control in Networked

   Systems, Santa Barbara California, Sep. 14-15 2012, To Appear.

5. N. Chopra, "Output Synchronization on Strongly Connected Graphs," IEEE Transactions on Automatic

   Control, In Press, 2012.

6. Y-C. Liu and N. Chopra, "Control of Robotic Manipulators under Input-Output Communication Delays:

   Theory and Experiments," IEEE Transactions on Robotics, Vol. 28, No. 3, pp. 742-751, 2012.

7. L. Sabattini, C. Secchi, and N. Chopra, "Decentralized Connectivity Maintenance for Networked

   Lagrangian Systems," In Proceedings of the IEEE International Conference on Robotics and Automation, St. Paul MN, 14-18 May 2012, pp. 2433 - 2438.

Award ID: 0931661