A self-locking foldable mechanism enables a robotic arm to be folded flat and to maintain high stiffness when deployed.

In this paper, we present a milli-scale integrated jumping-crawling robot that can adjust its launch trajectory and upright itself. This multi-modal robot shows an enhanced performance of overcoming obstacles compared to a robot with a single locomotion mode. To make this possible, the robot uses a newly developed jumping module with improved energy storing-capacity and a height-adjustable active clutch. The jumping module utilizes both linear springs and torsional springs to maximize the energy-storing capacity under the given limit of structural robustness. To adjust the quantity of stored energy and release the energy at any state, an active clutch mechanism based on a single DC motor is developed, which enables the robot to control both jump timing and height. Also, an active shell allows the robot to upright itself after landing and to continue jumping-crawling. The jumping module and the shell are integrated with the lightweight VelociRoACH crawler. To show the usability in real-world applications, the integrated jumping-crawling robot is tested on the cluttered terrain. In result, the robot reaches a target using jumping, crawling, and self-righting.

Chameleon tongue-like manipulators have the potential to be quite useful for mobile systems to overcome access issues by allowing them to reach distant targets in an instant. For example, a quadrotor with this manipulator will be able to snatch distant targets instead of hovering and picking up. In this letter, we present a chameleon-inspired shooting and rapidly retracting manipulator, which is lightweight, compact, and ultimately suitable for mobile systems. To make this possible, two design strategies are proposed: to use a wind-up spring as an energy source and to employ an active clutch to selectively distribute the energy. The wind-up spring enables the device to keep supplying the stored energy for a long time, compared to normal torsion springs. The active clutch controls the direction and the timing of the energy supply, which allows to deploy and retract the end-effector. Thanks to these design strategies, the device achieves snatching manipulation while maintaining compact and lightweight. In result, the Snatcher has a size of 120x85x85mm, weighs 117.48g, and brings a 30g mass located at 0.8m away within 600ms.

In this paper, we suggest a novel transmission for the DC motor-based flapping-wing micro aerial vehicles (FWMAVs). Most DC motor-based FWMAVs employ linkage structures, such as a crank-rocker or a crank-slider, which are designed to transmit the motor’s rotating motion to the wing’s flapping motion. These transmitting linkages have shown successful performance; however, they entail the possibility of mechanical wear originating from the friction between relative moving components and require an onerous assembly process owing to several tiny components. To reduce the assembly process and wear problems, we present a geometrically constrained and origami-based spherical six-bar linkage. The origami-based fabrication method reduces the number of the relative moving components by replacing rigid links and pin joints with facets and folding joints, which shortens the assembly process and reduces friction between components. The constrained spherical six-bar linkage enables us to change the motor’s rotating motion to the linear reciprocating motion. Due to the property that every axis passes through a single central point, the motor’s rotating motion is filtered at the spherical linkage and does not transfer to the flapping wing. Only linear motion, therefore, is passed to the flapping wing. To show the feasibility of the idea, a prototype is fabricated and analyzed by measuring the flapping angle, the wing rotation angle and the thrust.

Hopping locomotion has the potential to enable small-scale robots to maneuver lands quickly while overcoming obstacles bigger than themselves. To make this possible, in this paper, we propose a novel design of a high-power linear actuator for a small-scale hopper. The key design principle of the linear actuator is to use a power spring and an active clutch. The power spring provides a near constant torque along the wide range of output displacement. The active clutch controls the moving direction and operation timing of the linear actuator, which enables the hopper to take off at the right timing. As a result, the hopper has a size of 143 mm, a mass of 45.9 g, and hops up to 0.58 m.

A deployable robotic arm can be a useful tool for mobile systems to widen accessible areas without removing mobility. For practical use, the deployable robotic arm needs to satisfy two requirements: a high extension–compression ratio and robust structural stiffness against the environment. To this end, this paper suggests, for the first time, an origami-inspired zipper chain to achieve a highly compact, one-degree-of-freedom zipper chain arm. The key component is the foldable chain, which innovatively increases the space-saving capability in the stowed state. The foldable chain is fully flattened in the stowed state, allowing for storage of many more chains in the same space. Moreover, a transmission system was designed to transform a 2D flat pattern into a 3D chain shape in order to control the length of the origami zipper. Additionally, an empirical parametric study was performed to choose design parameters to maximize the bending stiffness. For the feasibility test, a prototype was built and performance tests were executed in relation to extension length, speed, and structural robustness.