Although legged robots have demonstrated effective mobility in some natural settings, as robot size decreases, obstacles in their environment become challenging to overcome. Small arthropods scale obstacles many times their size through jumps powered by mechanisms that overcome speed and power limitations of muscle alone. The motivation for this study was to explore the marriage of impulsive (jumping) and nonimpulsive (cyclic legged ambulation) behaviors in a centimeter-scale robot. Here, jumping is achieved by striking the ground with a bioinspired appendage connected to a parallel linkage. As the linkage configuration passes through the singularity, a torque reversal occurs whereby elastic energy slowly stored by force-dense velocity-limited shape memory alloy actuators is rapidly released. A passively driven elastic hinge is introduced in the striking arm to mediate ground contact forces and direct jumping. High-speed video recording of the 14-millisecond launch phase reveals previously undocumented takeoff dynamics closely resembling those of springtails. A dynamic model was derived, and an experimentally validated simulation was used to optimize the design of key components. The 2.2-gram, 6.1-centimeter-long mechanism achieved a maximum horizontal jumping distance of 1.4 meters (23 body lengths), surpassing that of similarly sized insects. The mechanism was integrated with an agile quadrupedal microrobot with leg articulation suitable to achieve the ideal jumping posture. The platform demonstrated repeatable directional takeoffs and upright landings, enabling complex maneuvers to overcome obstacles and gaps. Last, we used this bioinspired robot to offer reflection on hypotheses related to springtail jumping behavior.

The rising number of devices created using pop-up microelectromechanical systems (MEMS) and related folding-based assembly techniques highlights the need for robust design and manufacturing workflows to support the wide range of device variations. To push the bounds of miniaturization, design for manufacturing is key in dealing with fabrication challenges. Iterative building of intermediate device prototypes is a promising way to explore an often very large design space and can highlight mechanical limitations that may not be obvious to the designer. Manufacturing of pop-up MEMS devices is, however, typically a lengthy process with lamination taking a significant percentage of the build time, compared to layer machining and component assembly. To expedite the design process, researchers often prototype multiple iterations at larger scales prior to committing to at-scale designs. In this study, an at-scale rapid prototyping workflow for pop-up MEMS devices is introduced. This study also includes flexure design considerations for castellated hinges, to approach the behavior of an ideal pin joint. The new proposed workflow uses more accessible lower-cost equipment and materials and reduces lamination time by over 95% (10 min lamination vs a 3.5 h lamination) compared to the previous heated press process, which is validated through a series of prototypes. Manufacturing of pop-up MEMS devices is typically a lengthy process with lamination taking a significant percentage of the build time. Herein, an at-scale rapid prototyping workflow for pop-up MEMS devices is developed and validated through a series of prototypes. The proposed accelerated workflow is a promising way to explore a large design space and can expedite microrobot research. image

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 designed and modeled a striking microrobot to mimic the mantis shrimp's high speed appendage's striking behavior. Here, we utilize a similar mantis shrimp mechanism for small-scale throwing. After adapting the mechanism for projectiles, we describe improvements to the throwing speed via a process of modeling and experimental validation of key components. This work explores the inclusion of a passive joint on the throwing arm and different projectile carriage designs. The current device achieves throwing speeds of over 10 m/s for a 65 mg ball bearing, making it the fastest microrobot “pitcher” demonstrated to date.

Ultrafast movements propelled by springs and released by latches are thought limited to energetic adjustments prior to movement, and seemingly cannot adjust once movement begins. Even so, across the tree of life, ultrafast organisms navigate dynamic environments and generate a range of movements, suggesting unrecognized capabilities for control. We develop a framework of control pathways leveraging the non-linear dynamics of spring-propelled, latch-released systems. We analytically model spring dynamics and develop reduced-parameter models of latch dynamics to quantify how they can be tuned internally or through changing external environments. Using Lagrangian mechanics, we test feedforward and feedback control implementation via spring and latch dynamics. We establish through empirically-informed modeling that ultrafast movement can be controllably varied during latch release and spring propulsion. A deeper understanding of the interconnection between multiple control pathways, and the tunability of each control pathway, in ultrafast biomechanical systems presented here has the potential to expand the capabilities of synthetic ultra-fast systems and provides a new framework to understand the behaviors of fast organisms subject to perturbations and environmental non-idealities.

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 the scientific community. To study the underlying mechanisms and operating principles behind these behaviors, prior research has developed physical models that mimic the motions and speeds of mantis shrimp. That microrobot demonstrated speeds of approximately 5 m/s in water and 26 m/s in air. Here we utilize an accurate dynamical model of the four-bar mechanism and geometric latch observed in biological shrimp in a numerical trajectory optimization approach to find the design changes that can maximize the microrobot's striking velocities. Through a suboptimization problem maximizing the energy loaded in the mechanism's spring, we manage to improve the performance of the microrobot by over 58%, reaching tip velocities of $41.2 \pm 0.6$ m/s.

Efficient and effective generation of high-acceleration movement in biology requires a process to control energy flow and amplify mechanical power from power density-limited muscle. Until recently, this ability was exclusive to ultrafast, small organisms, and this process was largely ascribed to the high mechanical power density of small elastic recoil mechanisms. In several ultrafast organisms, linkages suddenly initiate rotation when they overcenter and reverse torque; this process mediates the release of stored elastic energy and enhances the mechanical power output of extremely fast, spring-actuated systems. Here we report the discovery of linkage dynamics and geometric latching that reveals how organisms and synthetic systems generate extremely high-acceleration, short-duration movements. Through synergistic analyses of mantis shrimp strikes, a synthetic mantis shrimp robot, and a dynamic mathematical model, we discover that linkages can exhibit distinct dynamic phases that control energy transfer from stored elastic energy to ultrafast movement. These design principles are embodied in a 1.5-g mantis shrimp scale mechanism capable of striking velocities over 26 m [Formula: see text] in air and 5 m [Formula: see text] in water. The physical, mathematical, and biological datasets establish latching mechanics with four temporal phases and identify a nondimensional performance metric to analyze potential energy transfer. These temporal phases enable control of an extreme cascade of mechanical power amplification. Linkage dynamics and temporal phase characteristics are easily adjusted through linkage design in robotic and mathematical systems and provide a framework to understand the function of linkages and latches in biological systems.

We present AutoConnect, an automatic method that creates customized, 3D-printable connectors attaching two physical objects together. Users simply position and orient virtual models of the two objects that they want to connect and indicate some auxiliary information such as weight and dimensions. Then, AutoConnect creates several alternative designs that users can choose from for 3D printing. The design of the connector is created by combining two holders, one for each object. We categorize the holders into two types. The first type holds standard objects such as pipes and planes. We utilize a database of parameterized mechanical holders and optimize the holder shape based on the grip strength and material consumption. The second type holds free-form objects. These are procedurally generated shell-gripper designs created based on geometric analysis of the object. We illustrate the use of our method by demonstrating many examples of connectors and practical use cases.

We present AutoConnect, an automatic method that creates customized, 3D-printable connectors attaching two physical objects together. Users simply position and orient virtual models of the two objects that they want to connect and indicate some auxiliary information such as weight and dimensions. Then, AutoConnect creates several alternative designs that users can choose from for 3D printing. The design of the connector is created by combining two holders, one for each object. We categorize the holders into two types. The first type holds standard objects such as pipes and planes. We utilize a database of parameterized mechanical holders and optimize the holder shape based on the grip strength and material consumption. The second type holds free-form objects. These are procedurally generated shell-gripper designs created based on geometric analysis of the object. We illustrate the use of our method by demonstrating many examples of connectors and practical use cases.