High altitude electromagnetic pulses (HEMPs) and solar-geomagnetic disturbances (GMDs) both have the potential to impact the reliable operation of the electric power grid. GMDs, and the low-frequency portion of HEMP insults, introduce currents into the grid that can result in the magnetic cores of large power transformers becoming saturated. This paper presents a novel approach to HEMP/GMD mitigation, wherein actively controlled voltage sources are utilized to nullify a low frequency EMP insult. This method is evaluated on several power system case studies, including a single transformer system, a 20-bus system, and a 150-bus system. Results show that the active mitigation is able to successfully prevent transformer saturation in all cases.

As the number of natural disasters and the duration of their aftermath continues to rise, the use of mobile and autonomous energy sources formed into a temporary and adaptive microgrid will improve response time and decrease overall recovery time. The optimal positioning of energy resources in the operating field is critical. There are many options for choosing an optimization technique but many of these assume specific connections between voltage source nodes and loads. This paper presents a brief overview of the genetic algorithm optimization in microgrid resource positioning in an operating field with obstacles. The indexing of the nodes and loads and the formulation for optimization of a general model of a microgrid system are presented. Next, the optimization of microgrids using the genetic algorithm approach is explained, as well as the shortest path algorithm used. The results show the success of optimization applied to a variety of test cases. Further research and expansions of optimization in the test cases are then explained.

This paper presents an architecture for the development of mobile microgrids using autonomous vehicles for the recovery of electrical power in postdisaster scenarios. The goal is to facilitate the integration of the different disciplines involved and address interrelated challenges in interaction between the disparate components of the system and the physical world. The architecture described in this paper has emerged through a combination of hardware development and experimental studies. The proposed layout will create an autonomous mobile microgrid system consisting of a team of ground robots capable of navigating in a disaster-affected area, making electrical connections, and supplying and controlling the electrical power needed by the loads in the area. This system has the scalability characteristics of an ad hoc system and can reconfigure itself depending on the changes in demanded performance of the microgrid.

This paper develops a novel control system design methodology that uniquely combines: concepts from thermodynamic exergy and entropy; Hamiltonian systems; Lyapunov's direct method and Lyapunov optimal analysis; electric AC power concepts; and power flow analysis. Relationships are derived between exergy/entropy and Lyapunov optimal functions for Hamiltonian systems. The methodology is demonstrated with a few fundamental numerical simulation examples: 1) a Duffing oscillator/Coulomb friction nonlinear model that employs PID regulator control; and 2) a linear PID tracking servo control design for a translational single robot link system. The control system performances are partitioned and evaluated based on exergy generation and exergy dissipation terms. This novel nonlinear control methodology results in both necessary and sufficient conditions for stability of nonlinear systems

An optimized path-planning approach is presented for flexible dynamic systems. Feedforward command profiles are determined for rest-to-rest large angle maneuvers that keep vibrations to a minimum. The performance index included both minimum energy and minimum time optimization problems. The feedfoward command profiles were generated by solving a discrete-time optimal control problem via discrete dynamic programming (DDP). A simple planar two-link flexible robot arm was utilized to demonstrate the DDP path-planning scheme. Numerical simulation results included: 1) minimum effort, 2) minimum effort with bounds, 3) minimum time, and 4) minimum torque-rate or power, respectively. The DDP approach demonstrated an effective alternative for numerical optimization, to generate optimal feedforward trajectory profiles.

This paper introduces a robust adaptive control architecture for nonholonomic mobile robots. The concept of backstepping provides a bridge between the kinematics and dynamics. In previous work normally only the vehicle steering, dependent upon the kinematics are considered for vehicle control. Improved tracking performance is achieved by including vehicle dynamics and robustness compensation for variances in parameters. Numerical simulations demonstrate the effectiveness of the robust adaptive control algorithm.

We present an output feedback sliding mode control (OFSMC) architecture for slewing flexible joint and link robot structures. A decoupled two-channel OFSMC is used to servo the flexible structure and suppress residual vibrations. A separate sliding surface is specified for each channel. The results of this study include the analytical dynamic and control system development with experimental verification. The control algorithm uses the output sensor data from the encoder and strain sensor along with filters to derive velocity information to compute the control effort for the motor and strain actuators. Near-minimum time maneuvers based on an equivalent rigid structure are used to slew the flexible active structure. The tip mass was varied to evaluate control system robustness. Experimental slewing studies were performed to compare the benefits of using active rather than passive structures. In addition, the OFSMC was compared against a conventional PID controller. For the active case the experimental results showed a reduction in residual vibration and settling time.

This paper discusses how phase plane analysis can be used to describe the overall behaviour of single and multiple autonomous robotic vehicles with finite state machine rules. The importance of this result is that we can begin to design provably asymptotically stable group behaviours from a set of simple control laws and appropriate switching points with decentralized variable structure control. The ability to prove asymptotically stable group behaviour is especially important for applications such as locating military targets or land mines.

This paper describes two methods for controlling the surface of a liquid in an open container as it is being carried by a robot arm. Both methods make use of the fundamental mode of oscillation and damping of the liquid in the container as predicted from a boundary element model of the fluid. The first method uses an infinite impulse response filter to alter an acceleration profile so that the liquid remains level except for a single wave at the beginning and end of the motion. The motion of the liquid is similar to that of a simple pendulum. The second method removes the remaining two surface oscillations by tilting the container parallel to the beginning and ending wave. A double pendulum model is used to determine the trajectory for this motion. Experimental results of a FANUC S-800 robot moving a 230 mm diameter hemispherical container of water are presented.

Angularly accelerating a cantilevered rod which sags under gravity couples the out-of-lane dynamics of the flexible rod and causes oscillation in both the horizontal and vertical planes. A parameter-scheduled trajectory planner has been analytically developed and experimentally implemented on a commercial robot to suppress the first mode of these vibrations during a horizontal angular move. A load was attached to the tip of the rod and the resulting static, out-of-plane, hub torque was measured with a force-torque sensor. This torque was used to predict the period of the horizontal first mode of vibration of the payload (rod and attached load) from a nonlinear function in order to calculate (schedule) the appropriate control parameters for the angular move. This system has been implemented on a Cincinnati Milacron T3-786 robot, and vibration-suppressed trajectories (which reduce the coupled residual vibrations by over 90%) have been performed by the robot for various payloads.>