71 accepted papers
California blackworms constitute a recently identified animal system exhibiting unusual collective behaviors, in which dozens to thousands of worms entangle to form a “blob” capable of actions like locomotion as an aggregate. In this paper we describe a system of pneumatic soft robots inspired by th
Osmosis-driven actuation offers a promising strategy for developing untethered, environmentally responsive soft and shape shifting mechanisms and robots. In this work, we explore the use of superabsorbent polymer (SAP) pellets as large-scale, shape-morphing actuators. Upon exposure to water, these a
While previous studies have explored electroadhesive climbing using the insect-scale Harvard Ambulatory Microrobot platform, the robot's ability to climb reliably over irregular terrain has remained limited. To evaluate potential solutions, we conducted an investigation of the electroadhesive pad de
Tracking and following objects of interest is critical to several robotics use cases, ranging from industrial automation to logistics and warehousing, to healthcare and security. In this paper, we present a robotic system to detect, track, and follow any object in real-time. Our approach, dubbed <it
Soft, wearable systems hold promise for a wide variety of new or enhanced applications in the realm of human-computer interaction, physiological monitoring, wear-able robotics, and a host of other human-centric devices. Soft sensor systems have been developed concurrently in order to allow these wea…
Mantis shrimp are distinguished by their high-speed striking appendages, which achieve tip speeds on the order of tens of meters per second underwater in order to break open the shells of their prey. To better understand the mechanics by which mantis shrimp achieve these speeds, prior research has d
Gripper hardware design often involves a trade-off between distinct and sometimes opposing goals (e.g., high grasping force vs. gentleness). To address this trade-off within a single device, we present a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink
Proprioception, or the perception of the configuration of one's body, is challenging to achieve with soft robots due to their infinite degrees of freedom and incompatibility with most off-the-shelf sensors. This work explores the use of inertial measurement units (IMUs), sensors that output orientat…
Insects can locomote readily in challenging environments, such as over steep inclines and across obstacle-laden terrains, which still frustrate robots of similar size. In this work, inspired by the passive compliant properties of insect limbs, we use the insect-scale Harvard Ambulatory Microrobot an…
As robots begin to move from structured industrial environments to the real world, they must be equipped to not only safely interact with the environment, but also reason about how to leverage contact to perform tasks. In this work, we develop a modeling and motion planning framework for continuum r…
In-hand manipulation is necessary, yet challenging for robotic hands as robots begin to interact with real-world objects and environments. The intentional incorporation of an active palm can lead to improved dexterity. In this work, we demonstrate how controlling the palm-object interaction enables
Fluidic soft actuators have been widely used for applications where compliance is desirable – such as in delicate robotic manipulation. As their operation is based on pressurization, fluidic actuators typically rely on bulky, rigid pumps, valves, and pressure regulators for control. This dependence
Mantis shrimp produce one of the fastest strikes in the animal kingdom, their striking appendages reaching tip velocities of tens of meters per second underwater. Their ultrafast movement is capable of crushing the shells of prey and generating cavitation bubbles, and has long raised interest from t…
Many insects utilize both amplitude and frequency modulation of their wingstrokes to control flight, a combination with potential advantages for flapping-wing micro-aerial vehicle (FWMAV) flight control as we attempt to mimic the agility of small biological fliers. However, frequency-modulated contr
Flapping-wing micro-aerial vehicles (FWMAVs) provide unique control challenges both in control authority and in the complexity of modeling flapping-wing aeromechanics. We provide a control-critical, closed-form model for FWMAV flight, particularly tailored to augmenting yaw torque authority of the v
This paper describes the development of a modular end-effector system (MEES) for autonomous robotic maintenance and repair tasks. The design consists of the following major components: Robot Side Mating Socket Module (RSMS), End-Effector Side Mating Socket Module (EEMS), the Modular Camera System (M…
In this paper, we discuss the role of gripper compliance in successful grasping and manipulation of thin, flexible materials. We show, both conceptually and empirically, that each axis of compliance in a planar gripper provides unique benefits in this domain. Vertical compliance allows robust graspi…
To deploy robots outside of laboratory environments, they must be able to locomote on natural, unstructured terrain. While perception and control strategies for terrain navigation and obstacle avoidance have been developed for human-scale robots, microrobots are often too small to carry the sensors,…
Soft robotsoffer a host of benefits over traditional rigid robots, including inherent compliance that lets them passively adapt to variable environments and operate safely around humans and fragile objects. However, that same compliance makes it hard to use model-based methods in planning tasks requ
McKibben artificial muscles, comprised of an expandable bladder wrapped in a double-helix-braided sheath, have the ability to generate forces without restricting motion to occur exclusively along the direction of actuation. This makes them attractive for a variety of applications including soft, wea
Soft robotics has seen an exponential growth in the past decade, in part because the transition to soft materials has made a wider range of applications possible. Tasks involving contact with fragile objects or unstructured environments are particularly amenable to devices based on soft materials. T…
In-hand manipulation is challenging for soft robotic hands, especially in the real world where robots encounter a variety of object sizes and shapes. As such, the role of the palm is crucial, providing stabilizing contact to objects during grasping and manipulation, and controlling the position of o…
Engineers and scientists often rely on their intuition and experience when designing soft robotic systems. The development of performant controllers and motion plans for these systems commonly requires time-consuming iterations on hardware. We present the SoMo (Soft Motion) toolkit, a software frame…
The need for robotic hands capable of gentle in-hand manipulation is growing rapidly as robots enter the real world. In this work, we show that the arrangement of digits in a soft robotic hand has a strong effect on in-hand manipulation capabilities. Introducing task-based performance metrics which…
In this letter, we show that soft robotic hands provide a robust means of performing basic primitives of in-hand manipulation in the presence of uncertainty. We first discuss the design of a prototype hand with dexterous soft fingers capable of moving objects within the hand using several basic moti
Movement in bio-inspired robots typically relies on the use of a series of actuators and transmissions with one or more degrees of freedom (DOF), allowing asymmetrical ellipsoidal gaits for use in walking, running, swimming, and crawling. In an effort to simplify these multi-component systems, we pr…
Many insects demonstrate remarkable locomotive capabilities on inclined or even inverted surfaces. Achieving inverted locomotion is a challenge for legged insect-scale robots because repeated attachment and detachment to a surface usually requires the design of special climbing gaits, adhesion mecha
The ability to efficiently and precisely manipulate objects in inaccessible environments is becoming an essential requirement for many applications of mobile robots, particularly at small sizes. Here, we propose and implement a mobile micromanipulation solution using a piezoelectric microgripper int
Here we present HAMR-Jr, a 22.5mm, 320mg quadrupedal microrobot. With eight independently actuated degrees of freedom, HAMR-Jr is, to our knowledge, the most mechanically dexterous legged robot at its scale and is capable of high-speed locomotion (13.91bodylengthss-1) at a variety of stride frequenc…
Soft strain sensors have been explored as an unobtrusive approach for wearable motion tracking. However, accurate tracking of multi degree-of-freedom (DOF) noncyclic joint movements remains a challenge. This paper presents a soft sensing shirt for tracking shoulder kinematics of both cyclic and rand…
We present a novel paradigm and algorithm for optimal design of underactuated robot platforms in highly-constrained nonconvex parameter spaces. We apply this algorithm to two variants of the mature RoboBee platform, numerically demonstrating predicted performance improvements of over 10% in some cas…
Soft robots require strong, yet flexible actuators for locomotion and manipulation tasks in unstructured environments. Dielectric elastomer actuators (DEAs) are well suited for these challenges in soft robotics because they operate as compliant capacitors and directly convert electrical energy into
Laryngeal cancer treatments, while curative, often lead to voice impairment. Minimally invasive surgical methods that facilitate greater preservation of healthy tissue have recently emerged, but they are still limited in important ways. In this work, we describe a device that combines the advantages…
Soft robotics has yielded numerous examples of soft grippers that utilize compliance to achieve impressive grasping performances with great simplicity, adaptability, and robustness. Designing soft grippers with substantial grasping strength while remaining compliant and gentle is one of the most imp…
Remoras employ their adhesive discs to rapidly attach to and detach from a wide range of marine surfaces. By analyzing high-speed images of remoras' (Echeneis naucrates) hitchhiking behavior, we describe the fish's detachment mechanism as a lip curling up to break the seal between the disc and subst…
Sea urchins can easily navigate a wide range of challenging environments through the coordinated action of thousands of individually addressable rigid protective spines and flexible, reversibly adhesive tube feet. To investigate the potential implementation of these unusual locomotory appendages in
A hybrid manufacturing process combining abrasive jet and laser micromaching enables the creation of living hinges in nitinol that retain the superelastic properties of the bulk material. The former selectively etches through the thickness of a workpiece and the latter defines the part's final geome…
Flapping-wing micro-aerial vehicles rely on subtle changes in the kinematics of high-frequency wing flapping to produce roll, pitch, and yaw torques. To generate yaw torque, the Harvard RoboBee changes the ratio of upstroke to downstroke speed (“split-cycling”) by applying a second harmonic to the f…
The development of soft, compliant force sensors is greatly sought after in areas such as soft robotics and prosthetics. Nevertheless, solutions for measuring forces in multiple axes, while being mechanically compliant, have been few and far between. Here we present a compliant sensor able to detect…
Modular robotic systems that integrate distally with commercially available endoscopic equipment have the potential to improve the standard-of-care in therapeutic endoscopy by granting clinicians with capabilities not present in commercial tools, such as precision dexterity and feedback sensing. Wit
Movement in echinoderms is facilitated by the coordinated activity of thousands of individually addressable and reversibly adhesive tube feet. To investigate the potential applicability of these unique biological actuators as a locomotory structure for robotics applications, we describe here the des
Dynamic tactile displays represent a class of haptic devices of particular interest to the blind and visually impaired. Despite many years of research and development efforts, the low-cost, low-power, compact tactile display remains elusive. This paper describes a low-cost electromechanical actuator…
We present a power and control autonomous, insect-scale legged robot the Harvard Ambulatory MicroRobot with RF communication (HAMR-F). At only 2.8 g and 4.5 cm in length, HAMR-F is capable of locomotion at speeds up to 17.2 cm/s (3.8 body lengths per second) with an onboard battery. Two microcontrol
Force feedback during robotic surgery is critical in order to minimize potential injury to the patient and decrease recovery time from surgical procedures. Here we describe the use of a novel strain gauge printing method to apply low profile, low cost sensors directly to the surface of da Vinci surg…
In this work, we show that sensors based on soft, intentionally-lossy optical waveguides are well-suited for soft robotic grasping applications in the deep-sea. Each finger of a soft robotic hand is outfitted with a 2×1 array of optical sensing elements to enable proprioception and contact force sen…
Piezoelectric materials are an attractive option for electromechanical transduction on the mesoscale due to their intrinsic high force production, large bandwidth, and favorable scaling characteristics. However, the small displacements they inherently produce are typically too small to be directly u…
This paper develops a custom motion capture system that uses vision-based methods to rapidly and accurately track the body and leg position/orientation of a 1.43g legged microrobot, the Harvard Ambulatory MicroRobot (HAMR). Two new generalized metrics for quantifying locomotion performance are defin…
A multilayer fabrication method has been used to create crawling soft robots based on dielectric elastomer actuators. These actuators are created without the need for pre-stretch, eliminating the need for rigid components. A four-legged, multi-gait capable crawler can be fabricated in a matter of ho…
`Snap-On' robotic modules that can integrate distally with existing commercially-available endoscopic equipment have the potential to provide new capabilities such as enhanced dexterity, bilateral manipulation and feedback sensing with minimal disruption of the current clinical workflow. However, th…
Onboard vision sensing is a current challenge in micro-scale robotics. Small flapping-wing robots such as the RoboBee present significant constraints on power, weight, and image quality for an onboard vision sensor. Here we report the integration of a 1 × 1 × 1.7 mm camera capable of video capture i…
This paper presents an off-board trajectory controller for a range of stride frequencies (2-45 Hz) that enables zero-radius turns and holonomic control on one of the smallest and fastest legged robots, the Harvard Ambulatory MicroRobot (HAMR). An experimental model is used as the basis for control t…
Wearable robotic systems which aid or enhance human performance are the subject of substantial ongoing research efforts. Soft exosuits to assist with walking represent one class of system that leverage textiles and apparel to provide a lightweight and nonrestrictive means to interface to the lower e…
We present an off-board phase estimator and controller for leg position near the resonance of the Harvard Ambulatory MicroRobot's (HAMR) two degree-of-freedom transmission. This control system is a first step towards leveraging the significant increase in stride length at transmission resonance for…
Many areas of robotics, particularly locomotion and grasping, can benefit from the ability to modulate friction on surfaces that come into contact with objects in the environment. Previous research has tried to address the challenge of tunable friction; however, those efforts only provide modest gai…
Small, lightweight micro-aerial vehicles (MAVs) must rely on a limited number of actuators for flight stability and control. A method for six-degree of freedom control in a dual-actuator MAV has been previously proposed which employs stroke amplitude, bias, and split-cycle timing modulation. This co
This paper presents a biologically inspired, 3.2g untethered vehicle capable of both active (flapping) and passive (gliding) flight. We discuss the overall vehicle design, as well as its validation with thrust data from benchtop testing, simulation, and flight test results. The vehicle has one pair
Self-folding provides an efficient way of creating complex 3D geometries from 2D composites. However, the precision of self-folding structures is often limited by the use of open-loop folding mechanisms. In this paper we demonstrate feedback-controlled self-folding using a shape memory polymer and o…
Here we experimentally quantify the effects of wing morphological and inertial parameters on flapping flight performance. Through running at-scale, passive pitching experiments with different wing designs, we compare the relative importance of wing inertia, wing shape, and wing-actuation pairing. We…
Insect-scale flying robots are currently unable to carry the power source and sensor suite required for autonomous operation. To overcome this challenge, we developed and experimentally verified a non-linear damping model of actuation-limited flapping-wing vehicles with passively rotating wing hinge
Burgeoning transendoscopic procedures, such as endoscopic submucosal dissection (ESD), provide a promising means of treating early-stage gastric neoplasia in a minimally-invasive way. However, the remote locations of these lesions, coupled with their origination in the submucosal layers of the gastr
This paper introduces a manufacturing technique which enables the integration of soft materials and soft fluidic micro-actuators in the Pop-up book MEMS paradigm. Such a technique represents a promising approach to the design and fabrication of low cost and scalable articulated mechanisms provided w
The agility and ease of control make a quadrotor aircraft an attractive platform for studying swarm behavior, modeling, and control. The energetics of sustained flight for small aircraft, however, limit typical applications to only a few minutes. Adding payloads - and the mechanisms used to manipula
This paper presents the design and control of a teleoperated robotic system for dexterous micromanipulation tasks at the meso-scale, specifically open microsurgery. Robotic open microsurgery is an unexplored yet potentially a high impact area of surgical robotics. Microsurgical operations, such as m…
Without sufficient payload capacity to carry necessary electronic components, flying robots at the scale of insects cannot fly autonomously. Using a simple scaling heuristic to determine a few salient vehicle properties, we develop a vehicle design that possesses the requisite payload capacity for t…
Full autonomy remains a challenge for miniature robotic platforms due to mass and size requirements of on-board power and control electronics. This paper presents a solution to these challenges with a 2.3g autonomous legged robot. An off-the-shelf optical mouse sensor is adapted for use on the Harva…
Here we present a suite of theoretical, computational, and experimental studies culminating in the first aerial and aquatic capable insect-scale robot. We develop a computational fluid dynamics (CFD) simulation to model fluid-wing interaction in air and water. From CFD and a system dynamics analysis…
This paper presents a non-linear, dynamic model of the flexure-based transmission in the Harvard Ambulatory Microrobot (HAMR). The model is derived from first principles and has led to a more comprehensive understanding of the components in this transmission. In particular, an empirical model of the…
Self-folding is a promising technique for assembling robots from flat sheets. However, existing implementations do not include reliable methods for sensing the folding angle, making feedback control impossible. In this paper, we present novel angle sensors for foldable robots and machines. They are…
The Harvard Robobee is a fly-sized aerial vehicle that can perform controlled flight maneuvers. But this robot is unable to control its yaw or heading angle to a desired value. Motivated by this deficiency, we propose a new method to produce yaw-axis rotations. Termed wriggle-steering, it consists o…
Self-assembling robots can be transported and deployed inexpensively and autonomously in remote and dangerous environments. In this paper, we introduce a novel self-assembling method with a planar pneumatic system. Inflation of pouches translate into shape changes, turning a sheet of composite mater…
Despite having achieved unconstrained stable flight, the insect-scale flapping-wing robot is still tethered for power and control. Towards the goal of operating a biologically-inspired robot autonomously outside of laboratory conditions. In this paper, we simulate outdoor disturbances in the laborat…