Effective locomotion at multiple stride frequencies using proprioceptive feedback on a legged microrobot

Doshi, Neel; Jayaram, Kaushik; Castellanos, Samantha; Kuindersma, Scott; Wood, Robert J.

doi:10.1088/1748-3190/ab295b

Cited by 24 publications

(22 citation statements)

References 113 publications

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“…Wood and co‐workers commonly utilize bimorph piezoelectric elements to realize complex motion, including flight (linear, bending, rotary) 120. Demonstrations include climbing microrobots (Figure 6e),121 microaerial vehicles, high speed microrobots such as the Harvard Ambulatory MicroRobot (HAMR‐VP) (Figure 6f),122 insect robots123 such as the centipede‐inspired robot in Figure 6g,124 proprioceptive, high speed quadrupedal robots (Figure 6h),125 and mini resonant ambulatory robots 106,118,126,127. The piezoelectric actuators in the HAMR, the centipede, and the RoboBee (Figure 6i–k) are composite laminates of two piezoelectric ceramic layers (PZT‐5H) with nickel electrodes bonded to a central conductive carbon fiber layer tipped with aluminum 5,123.…”

Section: Piezoelectric Ceramics Polymers and Compositesmentioning

confidence: 99%

Materials as Machines

2020

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of responsive materials as machines is in robotics. The vision, leadership, and research of Bar-Cohen is seminal in both invigorating and focusing current-day research activities to develop responsive materials [2] and implement [3] them as lightweight, dexterous, and gentle (e.g., soft) robotic elements. In this spirit, this review exhaustively details the materials, the nature of their stimuli-response, and discusses considerations for their implementation in robotic systems and subsystems.Robotics is a well-established but growing field of research. Sustained progress in both performance and functionality continue to be realized in commercial robotic systems largely based on conventional materials and their integration with mechanisms. A recent example is the Atlas robot from Boston Dynamics [4] (Figure 1a). The incorporation of stimuli-responsive materials in robotics has largely focused on component-level demonstrations to extend the performance of a subsystem (such as a hand or gripper).Stimuli-responsive materials, spanning nearly all classes of materials and size scales, are currently subject to widespread examination in corporate, government, and academic research laboratories (Figure 1b-d). [5][6][7] In some cases, these materials have already found widespread commercial implementation in end use and are comparatively mature. The materials and fundamentals of their responses are summarized in Figure 2. Shape memory alloys (SMAs) and ceramic piezoelectric materials are distinctive in that they are hard, stimuli-responsive materials. Deformation of these materials can produce large energy densities due to their inherent stiffness. Electroactive polymers (EAPs) remain a topic of considerable interest, particularly dielectric elastomer actuators (DEAs). Engineered systems are rapidly emerging and enabling performance gains in robotics, largely based on pneumatic or fluidic (such as HASEL [8] actuators) transport processes that localize deformation to generate force or produce motion. Soft materials, such as shape memory polymers (SMPs), hydrogels, and liquid crystalline polymer networks (LCNs) and elastomers (LCEs) may offer distinctive functional performance to robotic systems in allowing local control of deformation without the need for complex interfacing with mechanisms. As will be evident, each of these materials has inherent advantages and performance tradeoffs that must be considered in functional implementations. However, responsive material systems have a common obstacle to widespread use: the performance and Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walk...

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Section: Piezoelectric Ceramics Polymers and Compositesmentioning

confidence: 99%

Materials as Machines

2020

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“…1) Vertical Leg Stiffness: Template dynamics resulting from bioinspired locomotion models [20] such as Single Leg Inverted Pendulum (SLIP, [21]) and Lateral Leg Spring (LLS, [22]) have informed the design of robotic systems including HAMR. Specifically, recent studies [10] on HAMR have demonstrated the importance of vertical leg stiffness to robot locomotion performance as a function of locomotion frequency.…”

Section: Transmission Dynamicsmentioning

confidence: 99%

“…As a first step towards predicting the sagittal plane dynamics resulting from scaling down, we experimentally determined the stiffness of the lift transmission using the procedure described in Doshi et al, [10]. Using the experimental setup depicted in Figure 3a, we measured vertical stiffness as a function of leg height for each of the four lift transmissions and found that it ranged from 34.52 to 72.11 Nm −1 (Figure 3b).…”

Section: Transmission Dynamicsmentioning

confidence: 99%

“…In this work, we introduce a new smaller-scale version of HAMR-VI, hereafter referred to as HAMR-Jr (Figure 1). This robot builds on extensive previous work on the HAMR platform [12], [13], [14], [10]. In particular, its design is derived from HAMR-VI (4.51 cm long, 1.43 g mass, [13]), a robot capable of achieving high-speed, level ground locomotion using multiple closed-loop gaits [10] at a variety of leg cycling frequencies [14].…”

Section: Introductionmentioning

confidence: 99%

“…This robot builds on extensive previous work on the HAMR platform [12], [13], [14], [10]. In particular, its design is derived from HAMR-VI (4.51 cm long, 1.43 g mass, [13]), a robot capable of achieving high-speed, level ground locomotion using multiple closed-loop gaits [10] at a variety of leg cycling frequencies [14]. Despite measuring half the body length and less than one fourth the body mass relative to its larger counterpart, HAMR-Jr does not compromise any mechanical dexterity or control authority (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

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Scaling down an insect-size microrobot, HAMR-VI into HAMR-Jr

Jayaram¹,

Shum²,

Castellanos³

et al. 2020

Preprint

Self Cite

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Here we present HAMR-Jr, a 22.5 mm, 320 mg 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 (13.91 bodylengths s −1 ) at a variety of stride frequencies (1-200 Hz) using multiple gaits. We achieved this using a design and fabrication process that is flexible, allowing scaling with minimum changes to our workflow. We further characterized HAMR-Jr's open-loop locomotion and compared it with the larger scale HAMR-VI microrobot to demonstrate the effectiveness of scaling laws in predicting running performance.

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Multidirectional Planar Motion Transmission on a Single‐Motor Actuated Robot via Microscopic Galumphing

Tang,

Wang,

et al. 2023

Advanced Science

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Insect‐scale mobile robots can execute diverse arrays of tasks in confined spaces. Although most self‐contained crawling robots integrate multiple actuators to ensure high flexibility, the intricate actuators restrict their miniaturization. Conversely, robots with a single actuator lack the requisite agility and precision for planar movements. Herein, a novel eccentric rotation‐dependent multidirectional transmission is presented using a tilted eccentric motor and a simplistic two‐legged structural configuration for planar locomotion. The speed of the eccentric motor is modulated to enable alternating microscopic jumps to propel the system, creating a mode of motion analogous to galumphing of seals. Upon modeling the motion dynamics and conducting experiments, the effectiveness of direct motion transmission is substantiated through microscopic galumphing encompassing left/right crawling and straight‐forward crawling. Finally, a 1.2 g untethered robot is developed, which demonstrates enhanced straight crawling and spot turning, traverses narrow tunnels, and achieves precise movements. Therefore, the proposed motion‐transmission technique provides a comprehensive set of innovative solutions of underactuated agile robots.

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Effective locomotion at multiple stride frequencies using proprioceptive feedback on a legged microrobot

Cited by 24 publications

References 113 publications

Materials as Machines

Materials as Machines

Scaling down an insect-size microrobot, HAMR-VI into HAMR-Jr

Multidirectional Planar Motion Transmission on a Single‐Motor Actuated Robot via Microscopic Galumphing

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