Towards Effective and Efficient Sensing-Motion Co-Design of Swarming Cyber Physical Systems

The overall research objective of the project is to establish and demonstrate a generic motion-sensing co-design procedure that significantly reduces the complexity of mission design for swarm-ing CPS, and greatly facilitates the development of effective and efficient control and sensing strategies. The objective of the project will be achieved through the integration of three main com-ponents: the design of cooperative control and sensing strategies, the development of Magnetic-induction-based underwater communication and localization technique, and the design of smart-material actuated biorobotic fish. We summarize the achievements since the last reporting period as follows.

Cooperative Motion and Sensing Co-design (1) The simultaneous parameter identification and state estimation algorithms for advection-diffusion PDE is extended so that the algorithms can be applied to more general fields represented by nonlinear PDE. A sensing-motion co-planning strategy for reconstructing the spatially distributed field using a mobile sensor network is devel-oped. (2) A geometric reinforcement learning algorithm for real-time path planning for mobile sensor networks in the problem of reconstructing a spatial-temporal varying field is developed.(3) The feasibility and robustness of the proposed algorithms are validated in simulations using a reconstructed realistic CO2 field collected by a static sensor network.

Collision Avoidance (1) Collision avoidance laws developed using a collision cone approach, were applied to the scenario of hybrid-tailed robotic fish moving in dynamic environments and then were tested in an experimental set-up involving an actual robotic fish. (2) The problem of collision avoidance of objects whose shapes can change as a function of time, was addressed. Analytical expressions of the collision cones associated with such deforming objects were deter-mined, and these were subsequently integrated in a Lyapunov framework to determine analytical guidance laws for collision avoidance. (3) The problem of collision avoidance in n-dimensions was addressed. Collision cones associated with quadric surfaces moving in a n-dimensional configu-ration space are developed. (4) A rendezvous cone approach is developed, using which mobile agents with arbitrarily shaped sensing or communication zones, can rendezvous with one another to a specified depth of overlap.

Smart-material Actuated Biorobotic Fish (1) 2 dimensionally (2D) maneuverable robotic fish has been re-designed and fabricated for experimental validation of the collision avoidance control.(2) An IPMC water electrolysis enabled buoyancy control device has been developed. The device utilizes an IPMC water electrolyzer to generate gases for increasing buoyancy and solenoid valves to release gases for decreasing buoyancy. A feedback control algorithm has been developed for the device. (3) A 3D maneuverable robotic fish has been successfully developed. The robotic fish consists of an IPMC enabled buoyancy control device for depth control and a servo motor with asymmetric flapping for 2D planar motion control. An open loop 3D maneuvering test has been demonstrated with the robotic fish. A 3D dynamic model has been developed for the robotic fish and validated by the experimental data.

MI Underwater Communications & Localization (1) The system architecture of the new hy-brid MI-Acoustic underwater communication is developed. (2) The master-slave synchronization strategy is developed for hybrid MI-Acoustic, which achieves more than 3 orders of magnitudes lower synchronization error than the existing acoustic system. (3) The MI-assisted acoustic under-water distributed beamforming technique is developed to establish reliable long distance commu-nication between robot swarm to surface station.