The threat of a large-scale electromagnetic event having a negative impact on the electric grid is real. Whether human-caused, via the detonation of a nuclear device, or natural, via a high-intensity burst of solar radiation, our historic experience with these phenomena indicates that as a global community, we should be prepared for such events and know how to mitigate their impacts. Current studies and related discussions provide a wide range of damage assessments for these events. We recommend continuing current technical investigations and research as well as strengthening collaboration between stakeholders and experts. This would ensure future threats are addressed in a timely and effective manner.

Control of wire-borne underactuated brachiating robots requires a robust feedback control design that can deal with dynamic uncertainties, actuator constraints and unmeasurable states. In this paper, we develop a robust feedback control for brachiating on flexible cables, building on previous work on optimal trajectory generation and time-varying LQR controller design. We propose a novel simplified model for approximation of the flexible cable dynamics, which enables inclusion of parametric model uncertainties in the system. We then use semidefinite programming (SDP) and sum-of-squares (SOS) optimization to synthesize a time-varying feedback control with formal robustness guarantees to account for model uncertainties and unmeasurable states in the system. Through simulation, hardware experiments and comparison with a time-varying LQR controller, it is shown that the proposed robust controller results in relatively large robust backward reachable sets and is able to reliably track a pre-generated optimal trajectory and achieve the desired brachiating motion in the presence of parametric model uncertainties, actuator limits, and unobservable states.

This paper describes the dynamic modeling and locomotion control of a two-link underactuated brachiating robot traversing a flexible cable. A multi-body system comprised of a two-link robot, a flexible cable, and coupling soft junctions is modeled dynamically. This model is used to formulate an energy-minimizing optimal control strategy that includes the effects of cable vibration induced by robot locomotion. Optimized trajectories and control torque profiles are obtained via multiple-shooting and parametric trajectory approaches. Simulation results show that these optimal torque profiles result in energy-efficient continuous brachiation over a flexible cable. Additional studies examine how the optimal torque profiles change depending on the robot's initial position along a catenary cable.

A novel brachiating robot design is presented for the purpose of traversing elevated wire networks. The robot is capable of moving along a single wire and between parallel wires, thereby enabling traversal of a two-dimensional space. Several novel features distinguish this design compared to previous brachiating robots. These include the ability to transition to and from both “rope” and “ladder” brachiation modes through an integrated wrist, a locking hand design for minimal power consumption, and distributed electronics packages that communicate wirelessly. A payload mounting point is installed, offering space for a variety of remote sensing packages. Experimental results using a prototype robot demonstrate that the system can reliably brachiate along a single wire, and can also reliably perform a swing-up maneuver after failed swing attempts or when transitioning between the rope and ladder locomotion modes. Energy expenditure for a single swing is quantified using experimental data. Overall, the proposed robot design is shown to provide a promising platform for traversal of wire networks in two dimensions.