Brian K. Taylor

Design and validation of a Whegs robot in USARSim

Simulation of robots and other vehicles in a virtual domain has multiple benefits. End users can employ the simulation as a training tool to increase their familiarity and skill with the vehicle without risking damage to the robot, potential bystanders, or the surrounding environment. Simulation allows researchers and developers to benchmark the robots performance in a range of scenarios without needing to physically have the robot and or necessary environment(s) present. Beyond benchmarking current designs, researchers and developers can use the information gathered in the simulation to guide and generate new design concepts. USARSim (Urban Search and Rescue Simulation) is a high fidelity simulation tool that is being used to accomplish these goals within the realm of search and rescue. One particular family of robots that can benefit from simulation in the USARSim environment is the Whegs#8482; series of robots developed in the Biologically Inspired Robotics Laboratory at Case Western Reserve University. Whegs robots are highly mobile ground vehicles that use abstracted biological principles to achieve a robust level of terrestrial locomotion. This paper describes a Whegs robot model that was designed and added to USARSims current array of robots. The model was configured to exhibit the same kind of behavioral characteristics found in the real Whegs vehicles. Once these traits were implemented, a preliminary validation study was performed to ensure that the robot interacted with its environment in the same way that the real-life robot would.

Descending commands to an insect leg controller network cause smooth behavioral transitions

Biological inspiration has long been pursued as a key to more efficient, agile and elegant control in robotics. It has been a successful strategy in the design and control of robots with both biologically abstracted and biomimetic designs. Behavioral studies have resulted in a good understanding of the mechanics of certain animals. However, without a better understanding of their nervous systems, the biologically-inspired observation-based approach was limited. The findings of Hess and Büschges, and Ekeberg et al. describing the neural mechanisms of stick insect intra-leg joint coordination have made it possible to control models of insect legs with a network of neural pathways they found in the animals thoracic ganglia. Our work with this model, further informed by cockroach neurobiological studies performed in the Ritzmann lab, has led to LegConNet (Leg Controller Network). In this paper we show that LegConNet controls the forward stepping motion of a robotic leg. With hypothesized additional pathways, some later confirmed by neurobiology, it can smoothly transition the leg from forward stepping to turning movements. We hypothesize that commands descending from a higher center in the nervous system inhibit or excite appropriate local neural pathways and change thresholds, which, in turn, create a cascade of reflexes resulting in behavioral transitions.

Analysis and benchmarking of a Whegs™ robot in USARSim

Simulation of robots in a virtual domain has multiple benefits, including serving as a training tool for end users and serving as a tool for robot testing and development. USARSim (Unified System for Automation and Robot Simulation) is a simulation tool that is being used to accomplish these goals. It is based on the Unreal Tournament 2004 gaming engine, which approximates the physics of how a robot interacts with its environment. A family of robots that can benefit from simulation in USARSim are Whegstrade* robots. Developed in the Biorobotics Laboratory at Case Western Reserve University (CWRU), Whegstrade robots are highly mobile ground vehicles that use abstracted biological principles to achieve a robust level of locomotion, including passive gait adaptation and enhanced climbing abilities. This paper describes a Whegstrade robot model that was constructed and benchmarked in USARSim. The model was given the same kinds of physical characteristics found in real Whegstrade vehicles. With these traits in place, a validation study was performed for the simulation by comparing the rotational body motions of the virtual and real robot. Specifically, we examine the robotpsilas pitch and roll ranges and frequencies (found to be about 10 degrees to 12 degrees and 5.5 Hz respectively). By altering the simulation parameters in a physically relevant way, the virtual robotpsilas performance was moved to be more in line with these values.

Modeling, validation and analysis of a Whegs robot in the USARSim environment

Simulation of robots in a virtual domain has multiple benefits. End users can use the simulation as a training tool to increase their skill with the vehicle without risking damage to the robot or surrounding environment. Simulation allows researchers and developers to benchmark robot performance in a range of scenarios without having the physical robot or environment present. The simulation can also help guide and generate new design concepts. USARSim (Unified System for Automation and Robot Simulation) is a tool that is being used to accomplish these goals, particularly within the realm of search and rescue. It is based on the Unreal Tournament 2004 gaming engine, which approximates the physics of how a robot interacts with its environment. A family of vehicles that can benefit from simulation in USARSim are WhegsTM robots. Developed in the Biorobotics Laboratory at Case Western Reserve University, WhegsTM robots are highly mobile ground vehicles that use abstracted biological principles to achieve a robust level of locomotion, including passive gait adaptation and enhanced climbing abilities. This paper describes a WhegsTM robot model that was constructed in USARSim. The model was configured with the same kinds of behavioral characteristics found in real WhegsTM vehicles. Once these traits were implemented, a validation study was performed using identical performance metrics measured on both the virtual and real vehicles to quantify vehicle performance and to ensure that the virtual robots performance matched that of the real robot.

A Miniature Vehicle with Extended Aerial and Terrestrial Mobility

This chapter describes the design, fabrication, and field testing of a small robot (30.5 cm wingspan and 30.5 cm length) capable of motion in both aerial and terrestrial mediums. The micro-air–land vehicle (MALV) implements abstracted biological inspiration in both flying and walking mechanisms for locomotion and transition between modes of operation. The propeller-driven robot employs an undercambered, chord-wise compliant wing to achieve improved aerial stability over rigid-wing micro-air vehicles (MAVs) of similar size. Flight maneuverability is provided through elevator and rudder control. MALV lands and walks on the ground using an animal-inspired passively compliant wheel-leg running gear that enables the robot to crawl and climb, including surmounting obstacles larger than its own height. Turning is accomplished through differential activation of wheel-legs. The vehicle successfully performs the transition from flight to walking and is able to transition from terrestrial to aerial locomotion by propeller thrust on a smooth horizontal surface or by walking off a vertical surface higher than 6 m. Fabricated of lightweight carbon fiber the ~100 g vehicle is capable of flying, landing, and crawling with a payload exceeding 20% its own mass. To our knowledge MALV is the first successful vehicle at this scale to be capable of both aerial and terrestrial locomotion in real-world terrains and smooth transitions between the two.

Photonically controlled phased-array null steering using wavelets

This paper presents a modified version of a true time delay, broadband nulling approach to beamforming for a linear antenna array. The approach begins with the well known Davies method of narrowband beamforming; alters it to include time delays via tunable lasers and high dispersion optical fiber; and finally modifies the Davies tree itself to resemble decomposition filters from wavelet theory. This last modification cuts the required number of tunable lasers for an N element array but also decreases the number of independent null.