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Rigid-flex circuit boards are becoming more prevalent as the limits are pushed on the size, mass, and geometry of electronic systems. A key aspect of designing a rigid-flex printed circuit boards (PCB) system is an assessment of the dynamic properties of the PCB and predicting system performance under dynamic loading. Among current modeling methodologies for rigid-flex PCB, a simplified modeling methodology that adequately captures the system dynamics does not exist. This article presents a novel, computationally efficient approach for modeling rigid-flex PCB systems and the calibration of the material models via modal testing. The resulting simplified model is able to capture system frequencies, mode shapes, and representative force-displacement behavior. The proposed methodology is used to model NASA Jet Propulsion Laboratory's Pop-Up Flat Folding Explorer Robot (PUFFER) and assess the sensitivity of a system model to input parameters. [ABSTRACT FROM AUTHOR]

Relatively recent discoveries have shown that large quantities of water can be found on moons of some of the planets among the gas giants in our solar system. Robotic mobility systems can study the varied geology and origins of these bodies if they are able to navigate the complex terrains of ocean worlds. The topographical features of ocean worlds present a unique combination of challenges for mobility. These include cryogenic ice, penitentes, salt evaporites, chaotic regions, and regolith with uncertain shear and sinkage properties. Uncertainty in both terrain properties and geometry motivates design of a platform that is mobile within a large range of obstacle geometries and terrain properties. This article reports on a research effort to study the requirements and numerically optimize the kinematic parameters of the rover to satisfy these goals. The platforms selected in the process were further verified via simulation. A simulation and analysis of grousers generated suitable designs for interaction with similar ledges and rough terrain. From this analysis, a prototype was developed and tested to meet the wide range of topography and terramechanics conditions expected on these bodies. [ABSTRACT FROM AUTHOR]

Tactile sensing is an instrumental modality of robotic manipulation, as it provides information that is not accessible via remote sensors such as cameras or lidars. Touch is particularly crucial in unstructured environments, where the robot's internal representation of manipulated objects is uncertain. In this study we present the sensorization of an existing artificial hand, with the aim to achieve fine control of robotic limbs and perception of object's physical properties. Tactile feedback is conveyed by means of a soft sensor integrated at the fingertip of a robotic hand. The sensor consists of an optical fiber, housing Fiber Bragg Gratings (FBGs) transducers, embedded into a soft polymeric material integrated on a rigid hand. Through several tasks involving grasps of different objects in various conditions, the ability of the system to acquire information is assessed. Results show that a classifier based on the sensor outputs of the robotic hand is capable of accurately detecting both size and rigidity of the operated objects (99.36 and 100% accuracy, respectively). Furthermore, the outputs provide evidence of the ability to grab fragile objects without breakage or slippage e and to perform dynamic manipulative tasks, that involve the adaptation of fingers position based on the grasped objects' condition. [ABSTRACT FROM AUTHOR]

In this letter, three-dimensionally (3-D) printed shaped inhomogeneous dielectric lens antennas are synthesized using a novel approach based on geometrical optics (GO) and the particle swarm optimization (PSO) method. The GO method is used to trace rays to the aperture following the amplitude, phase, and polarization along curved space trajectories through inhomogeneous media to evaluate potential designs. These designs are specified by power series polynomials describing the surface topology and permittivity functions filling the volume of the shaped lens. The optimum design is obtained by integrating the GO analysis engine with the PSO into an optimization loop. The complex designed materials that result can be printed using new 3-D printers. New techniques are developed to print structures using fused deposition modeling (FDM), which contain complex overhanging features. Measured and simulated results are provided for all 3-D printed synthesized inhomogeneous lenses. [ABSTRACT FROM AUTHOR]

This article discusses hardware and software improvements to the RoboSimian system leading up to and during the 2015 DARPA Robotics Challenge (DRC) Finals. Team RoboSimian achieved a 5th place finish by achieving 7 points in 47:59 min. We present an architecture that was structured to be adaptable at the lowest level and repeatable at the highest level. The low-level adaptability was achieved by leveraging tactile measurements from force torque sensors in the wrist coupled with whole body motion primitives. We use the term ˵behaviors″ to conceptualize this low-level adaptability. Each behavior is a contact-triggered state machine that enables execution of short order manipulation and mobility tasks autonomously. At a high level, we focused on a teach-and-repeat style of development by storing executed behaviors and navigation poses in object/task frame for recall later. This enabled us to perform tasks with high repeatability on competition day while being robust to task differences from practice to execution. [ABSTRACT FROM AUTHOR]

This paper discusses hardware and software improvements to the RoboSimian system leading up to and during the 2015 DARPA Robotics Challenge (DRC) Finals. Team RoboSimian achieved a 5th place finish by achieving 7 points in 47:59 min. We present an architecture that was structured to be adaptable at the lowest level and repeatable at the highest level. The low-level adaptability was achieved by leveraging tactile measurements from force torque sensors in the wrist coupled with whole-body motion primitives. We use the term 'behaviors' to conceptualize this low-level adaptability. Each behavior is a contact-triggered state machine that enables execution of short-order manipulation and mobility tasks autonomously. At a high level, we focused on a teach-and-repeat style of development by storing executed behaviors and navigation poses in an object/task frame for recall later. This enabled us to perform tasks with high repeatability on competition day while being robust to task differences from practice to execution. [ABSTRACT FROM AUTHOR]

The Jet Propulsion Laboratory is developing a class of lightweight, highly mobile, crash-proof robots for reconnaissance and security applications. Arrays of independently compliant rotary microspines are used to build wheels that enable the robots to climb stairs, mount curbs, and climb rough vertical walls. This study presents many improvements to the rotary microspine wheels and several new configurations of the robotic platforms, including miniaturized robots weighing less than 10 g. New microspine flexure materials are presented including viscoelastic flexures that dampen the impact of individual hook elements, and mass-manufacturable microspines made using a single cast process over steel wire in place of elastic flexures. Rapid iteration of microspine designs was done using shape deposition manufacturing and a single-wheeled test robot. This process allowed new wheel concepts to go from design to testing in just three days. In addition, new configurations of robots with a powered wheel in the tail have improved reliability and demonstrated new capabilities like climbing heavily painted curbs, climbing stairs with overhanging face angles, and vertical climbing of concrete block buildings as tall as six stories. These results are presented in this paper and in the accompanying video. [ABSTRACT FROM PUBLISHER]

The use of bulk metallic glasses (BMGs) as the flexspline in strain wave gears (SWGs), also known as harmonic drives, is presented. SWGs are unique, ultra-precision gearboxes that function through the elastic flexing of a thin-walled cup, called a flexspline. The current research demonstrates that BMGs can be cast at extremely low cost relative to machining and can be implemented into SWGs as an alternative to steel. This approach may significantly reduce the cost of SWGs, enabling lower-cost robotics. The attractive properties of BMGs, such as hardness, elastic limit and yield strength, may also be suitable for extreme environment applications in spacecraft. [ABSTRACT FROM AUTHOR]