Michael Rubenstein

Legged machines are becoming increasingly agile and adaptive but they have so far lacked the morphological diversity of legged animals, which have been rearranged and reshaped to fill millions of niches. Unlike their biological counterparts, legged machines have largely converged over the past decade to canonical quadrupedal and bipedal architectures that cannot be easily reconfigured to meet new tasks or recover from injury. Here we introduce autonomous modular legs: agile yet minimal, single-degree-of-freedom jointed links that can learn complex dynamic behaviors and may be freely attached to form multilegged machines at the meter scale. This enables rapid repair, redesign, and recombination of highly-dynamic modular agents that move quickly and acrobatically (non-quasistatically) through unstructured environments. Because each module is itself a complete agent, the bodies that contain them can sustain deep structural damage that would completely disable other legged robots. We also show how to encode the vast space of possible body configurations into a compact latent design space that can be efficiently explored, revealing a wide diversity of novel legged forms.

Despite their growing popularity, swarms of robots remain limited by the operating time of each individual. We present algorithms that allow a human to sculpt a swarm of robots into a shape that persists in space perpetually, independent of onboard energy constraints, such as batteries. Robots generate a path through a shape such that robots cycle in and out of the shape. Robots inside the shape react to human initiated changes and adapt the path through the shape accordingly. Robots outside the shape recharge and return to the shape so that the shape can persist indefinitely. The presented algorithms communicate shape changes throughout the swarm using message passing and robot motion. These algorithms enable the swarm to persist through any arbitrary changes to the shape. We describe these algorithms in detail and present their performance in simulation and on a swarm of mobile robots. The result is a swarm behavior more suitable for extended duration, dynamic shape-based tasks in applications, such as entertainment, agriculture, and emergency response.

What happens when we read the Irish literary canon for energy? We find numerous mentions of wind power, solar power, petrol, coal, peat, gas, and dung, and we find these energy resources and infrastructures trellised into plot lines and character arcs in some unexpected ways in Irish literature, from Joyce and Beckett to Heaney and McCormack. What emerges is a partial but suggestive cognitive map – of Irish energy economies, ecologies, and phenomenologies – that reveals Ireland’s unique energy signature and at the same time links Ireland to other imperial and global regimes of petromodernity.

Communication and position sensing are among the most important capabilities for swarm robots to interact with their peers and perform tasks collaboratively.However, the hardware required to facilitate communication and position sensing is often too complicated, expensive, and bulky to be carried on swarm robots.Here we present Maneuverable Piccolissimo 3 (MP3), a minimalist, single motor drone capable of executing inter-robot communication via infrared light and triangulationbased sensing of relative bearing, distance, and elevation using message arrival time.Thanks to its novel design, MP3 can communicate with peers and localize itself using simple components, keeping its size and mass small and making it inherently safe for human interaction.Here we present the hardware and software design of MP3 and demonstrate its capability to localize itself, fly stably, and maneuver in the environment using peer-to-peer communication and sensing.

Communication and position sensing are among the most important capabilities for swarm robots to interact with their peers and perform tasks collaboratively. However, the hardware required to facilitate communication and position sensing is often too complicated, expensive, and bulky to be carried on swarm robots. Here we present Maneuverable Piccolissimo 3 (MP3), a minimalist, single motor drone capable of executing inter-robot communication via infrared light and triangulation-based sensing of relative bearing, distance, and elevation using message arrival time. Thanks to its novel design, MP3 can communicate with peers and localize itself using simple components, keeping its size and mass small and making it inherently safe for human interaction. We present the hardware and software design of MP3 and demonstrate its capability to localize itself, fly stably, and maneuver in the environment using peer-to-peer communication and sensing.

Human-swarm interaction is facilitated by a low-dimensional encoding of the swarm formation, independent of the (possibly large) number of robots. We propose using image moments to encode two-dimensional formations of robots. Each robot knows its pose and the desired formation moments, and simultaneously estimates the current moments of the entire swarm while controlling its motion to better achieve the desired group moments. The estimator is a distributed optimization, requiring no centralized processing, and self-healing, meaning that the process is robust to initialization errors, packet drops, and robots being added to or removed from the swarm. Our experimental results with a swarm of 50 robots, suffering nearly 50% packet loss, show that distributed estimation and control of image moments effectively achieves desired swarm formations.

Spherical robots typically require at least two actuators to achieve controlled 2D planar motion. Here we present Rollbot, the first spherical robot capable of controllably maneuvering on a 2D plane with a single actuator, challenging this assumption. Rollbot rolls on the ground in a circular pattern and controls its motion by changing the trajectory's curvature by accelerating and decelerating its single motor and the attached mass according to our derived quasi-stable state dynamics and control laws. We present the theoretical analysis, design, and control of Rollbot, and demonstrate its ability to move in a controllable circular pattern and follow waypoints, validating the efficacy of the proposed theoretical framework.

Complexity, cost, and power requirements for the actuation of individual robots can play a large factor in limiting the size of robotic swarms. Here we present PCBot, a minimalist robot that can precisely move on an orbital shake table using a bi-stable solenoid actuator built directly into its PCB. This allows the actuator to be built as part of the automated PCB manufacturing process, greatly reducing the impact it has on manual assembly. Thanks to this novel actuator design, PCBot has merely five major components and can be assembled in under 20 seconds, potentially enabling them to be easily mass-manufactured. Here we present the electro-magnetic and mechanical design of PCBot. Additionally, a prototype robot is used to demonstrate its ability to move in a straight line as well as follow given paths.

Despite their growing popularity, swarms of robots remain limited by the operating time of each individual. We present algorithms which allow a human to sculpt a swarm of robots into a shape that persists in space perpetually, independent of onboard energy constraints such as batteries. Robots generate a path through a shape such that robots cycle in and out of the shape. Robots inside the shape react to human initiated changes and adapt the path through the shape accordingly. Robots outside the shape recharge and return to the shape so that the shape can persist indefinitely. The presented algorithms communicate shape changes throughout the swarm using message passing and robot motion. These algorithms enable the swarm to persist through any arbitrary changes to the shape. We describe these algorithms in detail and present their performance in simulation and on a swarm of mobile robots. The result is a swarm behavior more suitable for extended duration, dynamic shape-based tasks in applications such as agriculture and emergency response.

Human-swarm interaction is facilitated by a low-dimensional encoding of the swarm formation, independent of the (possibly large) number of robots. We propose using image moments to encode two-dimensional formations of robots. Each robot knows its pose and the desired formation moments, and simultaneously estimates the current moments of the entire swarm while controlling its motion to better achieve the desired group moments. The estimator is a distributed optimization, requiring no centralized processing, and self-healing, meaning that the process is robust to initialization errors, packet drops, and robots being added to or removed from the swarm. Our experimental results with a swarm of 50 robots, suffering nearly 50% packet loss, show that distributed estimation and control of image moments effectively achieves desired swarm formations.

FireAntV3 uses a refined version of the 3D Continuous Docks to attach to other such docks at any location at any orientation with simple control and without alignment. The robot improves upon previous FireAnt-series robots by redesigning the locomotion drive system to improve mechanical and attachment reliability while also reducing the number of motors from six to three. We also expand the sensory capabilities of FireAntV3 to enable the robot to sense forces, sense the direction to a light source, and to sense contacting neighbors using vibrations. We validate this robot through full-robot tests demonstrating phototaxis and neighbor-detecting behavior. This letter also describes the method for manufacturing the continuous docks in a variety of geometries.

We present the Maneuverable Piccolissimo 2 (MP2), an autonomous, controllable, single motor micro aerial vehicle (MAV). The small size of MP2 makes it safe to operate in the presence of humans, and its simple design facilitates the creation of large swarms of capable MAVs. MP2 is equipped with on-board sensing capabilities and uses active environmental beacons to compute its three-dimensional position and yaw orientation. Its novel design enables autonomous takeoff, flight, and landing while maintaining a small, simple form factor. We describe a feedback controller and demonstrate its feasibility in a series of flight tests that display position holding, step response, and path following capabilities. The results indicate that MP2 is capable of controlled autonomous 3D flight with only one actuator.