Inspired by the exoskeletons of insects, we have developed a number of manufacturing methods for the fabrication of structures for attachment, protection, and sensing. This manufacturing paradigm is based on infrared laser machining of lamina and the bonding of layered structures. The structures have been integrated with an inexpensive palm-sized legged robot, the VelociRoACH [Haldane et al., 2013, “Animal-Inspired Design and Aerodynamic Stabilization of a Hexapedal Millirobot,” IEEE/RSJ International Conference on Robotics and Automation, Karlsruhe, Germany, May 6–10, pp. 3279–3286]. We also present a methodology to design and fabricate folded robotic mechanisms, and have released an open-source robot, the OpenRoACH, as an example implementation of these techniques. We present new composite materials which enable the fabrication of stronger, larger scale smart composite microstructures (SCM) robots. We demonstrate how thermoforming can be used to manufacture protective structures resistant to water and capable of withstanding terminal velocity falls. A simple way to manufacture traction enhancing claws is demonstrated. An electronics layer can be incorporated into the robot structure, enabling the integration of distributed sensing. We present fabrication methods for binary and analog force sensing arrays, as well as a carbon nanotube (CNT) based strain sensor which can be fabricated in place. The presented manufacturing methods take advantage of low-cost, high accuracy two-dimensional fabrication processes which will enable low-cost mass production of robots integrated with mechanical linkages, an exoskeleton, and body and limb sensing.

Many animals, modern aircraft, and underwater vehicles use fusiform, streamlined body shapes that reduce fluid dynamic drag to achieve fast and effective locomotion in air and water. Similarly, numerous small terrestrial animals move through cluttered terrain where three-dimensional, multi-component obstacles like grass, shrubs, vines, and leaf litter also resist motion, but it is unknown whether their body shape plays a major role in traversal. Few ground vehicles or terrestrial robots have used body shape to more effectively traverse environments such as cluttered terrain. Here, we challenged forest-floor-dwelling discoid cockroaches (Blaberus discoidalis) possessing a thin, rounded body to traverse tall, narrowly spaced, vertical, grass-like compliant beams. Animals displayed high traversal performance (79 ± 12% probability and 3.4 ± 0.7 s time). Although we observed diverse obstacle traversal strategies, cockroaches primarily (48 ± 9% probability) used a novel roll maneuver, a form of natural parkour, allowing them to rapidly traverse obstacle gaps narrower than half their body width (2.0 ± 0.5 s traversal time). Reduction of body roundness by addition of artificial shells nearly inhibited roll maneuvers and decreased traversal performance. Inspired by this discovery, we added a thin, rounded exoskeletal shell to a legged robot with a nearly cuboidal body, common to many existing terrestrial robots. Without adding sensory feedback or changing the open-loop control, the rounded shell enabled the robot to traverse beam obstacles with gaps narrower than shell width via body roll. Such terradynamically 'streamlined' shapes can reduce terrain resistance and enhance traversability by assisting effective body reorientation via distributed mechanical feedback. Our findings highlight the need to consider body shape to improve robot mobility in real-world terrain often filled with clutter, and to develop better locomotor-ground contact models to understand interaction with 3D, multi-component terrain.

Papers from a flagship conference reflect the latest developments in the field, including work in such rapidly advancing areas as human-robot interaction and formal methods. Robotics: Science and Systems VIII spans a wide spectrum of robotics, bringing together contributions from researchers working on the mathematical foundations of robotics, robotics applications, and analysis of robotics systems. This volume presents the proceedings of the eighth annual Robotics: Science and Systems (RSS) conference, held in July 2012 at the University of Sydney. The contributions reflect the exciting diversity of the field, presenting the best, the newest, and the most challenging work on such topics as mechanisms, kinematics, dynamics and control, human-robot interaction and human-centered systems, distributed systems, mobile systems and mobility, manipulation, field robotics, medical robotics, biological robotics, robot perception, and estimation and learning in robotic systems. The conference and its proceedings reflect not only the tremendous growth of robotics as a discipline but also the desire in the robotics community for a flagship event at which the best of the research in the field can be presented.

For maximum maneuverability, terrestrial robots need to be able to turn precisely, quickly, and with a small radius. Previous efforts at turning in legged robots primarily have used leg force or velocity modulation. We developed a palm-sized legged robot, called TAYLRoACH. The tailed robot was able to make rapid, precise turns using only the actuation of a tail appendage. By rapidly rotating the tail as the robot runs forward, the robot was able to make sudden 90° turns at 360 °s-1. Unlike other robots, this is done with almost no change in its running speed. We have also modeled the dynamics of this maneuver, to examine how features, such as tail length and mass, affect the robot's turning ability. This approach has produced turns with a radius of 0.4 body lengths at 3.2 body lengths per second running speed. Using gyro feedback and bang-bang control, we achieve an accuracy of ± 5° for a 60° turn.

This paper presents a six-legged, sprawl-tuned autonomous robot (STAR). This novel robot has a variable leg sprawl angle in the transverse plane to adapt its stiffness, height, and leg-to-surface contact angle. The sprawl angle can be varied from nearly positive 60 degrees to negative 90 degrees, enabling the robot to run in a planar configuration, upright, or inverted (see movie). STAR is fitted with spoke wheel-like legs which provide high electromechanical conversion efficiency and enable the robot to achieve legged performance over rough surfaces and obstacles, using a high sprawl angle, and nearly wheel-like performance over smooth surfaces for small sprawl angles. Our model and experiments show that the contact angle and normal contact forces are substantially reduced when the sprawl angle is low, and the velocity increases over smooth surfaces, with stable running at all velocities up to 5.2m/s and a Froude number of 9.8.

We study the locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of 3 mm diameter glass particles at speeds up to 5 body length/s, approaching the performance of certain desert-dwelling animals. To reveal how the robot achieves this performance, we used high-speed imaging to capture its kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated simulation of the granular medium. Average speeds measured in experiment and simulation agreed well, and increased nonlinearly with stride frequency, reflecting a change in propulsion mode. At low frequencies, the robot used a quasi-static "rotary walking" mode, in which the substrate yielded as legs penetrated and then solidified once vertical force balance was achieved. At high frequencies the robot propelled itself using the speed-dependent fluid-like inertial response of the material. The simulation allows variation of parameters which are inconvenient to modify in experiment, and thus gives insight into how substrate and robot properties change performance. Our study reveals how lightweight animals can achieve high performance on granular substrates; such insights can advance the design and control of robots in deformable terrains.

Rapid and consistent turning of running legged robots on surfaces with moderate friction is challenging due to leg slip and uncertain dynamics. A tail is proposed as a method to effect turns at higher yaw frequencies than can be obtained by differential velocity drive of alternate sides. Here we introduce a 100 mm scale dynamic robot - OctoRoACH - with differential-drive steering and a low-mass tail to investigate issues of yaw rate control. The robot without tail is underactuated with only 2 drive motors and mass of 35 grams including battery and control electronics. For some surface conditions, OctoRoACH can maintain heading or turning rate using only leg velocity control, and a basic rate-gyro-based heading control system can respond to disturbances, with a closed-loop bandwidth of approximately 1 Hz. Using a modified off-the-shelf servo for the tail drive, the robot responds to turning commands at 4 Hz and up to 400°/sec.

We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of closely packed 3 mm diameter glass particles at speeds up to 50 cm/s (5 body length/s), approaching the performance of small, highperforming, desert-dwelling lizards.To reveal how the robot achieves this high performance, we used high speed imaging to capture kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated discrete element method (DEM) simulation of the granular media.Average forward speeds measured in both experiment and simulation agreed well, and increased non-linearly with stride frequency, reflecting a change in the mode of propulsion.At low frequencies, the robot used a quasi-static "rotary walking" mode, in which the granular material yielded as the legs penetrated and then solidified once vertical force balance was achieved.At high frequencies, duty factor decreased below 0.5 and aerial phases occurred.The propulsion mechanism was qualitatively different: the robot ran rapidly by utilizing the speed-dependent fluid-like inertial response of the material.We also used our simulation tool to vary substrate parameters that were inconvenient to vary in experiment (e.g., granular particle friction) to test performance and reveal limits of stability of the robot.Using small robots as physical models, our study reveals a mechanism by which small animals can achieve high performance on granular substrates, which in return advances the design and control of small robots in deformable terrains.

Traditional monitoring of current flow in power lines involves breaking the circuit for through-the-sensor type monitoring or separating individual wires for around-the-conductor “clamp” metering. Such techniques for measurement are invasive and disruptive for many applications. Using 0.9 cm diameter permanent magnets attached to piezoelectric bimorph elements in conjunction with the fluctuating magnetic fields generated by alternating currents, sensors have been developed that enable in-situ, self-powered measurement of current flow without the need to encircle or disconnect the wire being measured. Whereas previous development [1, 2] of these devices has focused on two-wire applications for low (<600V) voltages, single-wire configurations for higher-voltage (up to 15kV) applications are also considered here. Outputs have been found to be linear through a wide ranges of current (0–200A on 0.6–120V AC), with resolution limited primarily by sensor distance from the target wire (3cm or less from wire edge). Sensitivity studies have been performed on conductors of varying dimensions (18 gauge to 4 gauge) and geometries (single conductor and two-wire) for known sensor placements and current flows. Initial integration has been performed with a wireless radio device to produce a self-contained sensor package 8cm by 10cm by 3cm that can sample data at 2 kHz and transmit results to a base station for further analysis. Initial numerical modeling of the magnetic field gradients around current-carrying wires has been performed to optimize sensor placement. Potential applications include customer (home, business, industry) and distribution grid-level monitoring.