An Integrated Soft Jumping Robotic Module Based on Liquid Metals

Abstract

The feasibility of liquid metal (LM) to serve for soft robots has been audaciously conceived. While most practices prefer its flexible conductivity or deformation, the LM‐activated hydrogen production with high efficiency should be emphasized that it provides another promising option about portable power supply for robots, which is beneficial for autonomy. Herein, a soft jumping robotic module featuring independent hydrogen supply and explosion‐actuated motion is proposed and fabricated. A necessary processing for raw materials is of priority that ensured convenient utilization in practice. Then the specific configuration of module is discussed and tested. As for applications, the module is integrated into a spherical‐shaped soft robot and a rigid‐wheeled robot as a functional unit. The former one shows vertical jumps, whereas the latter demonstrates its ability to jump over barriers. In general, the real‐time hydrogen supply together with pneumatic actuation from combustion enables a flexible way to realize powerful motion, and the modular characteristic expands its universality for more devices, enabling them with new forms of movement that is quite useful in expedition and rescue. An important trial toward the wish of more deeply combining LM with the development of soft robots and exploiting its diverse potentials is represented.

Liquid Metal Actuators: A Comparative Analysis of Surface Tension Controlled Actuation

“…[190] As a mobile robot, the liquid metal droplets are suitable for moving through a confined space such as channel and tube due to their high deformability. [47,53,191] • Self-Reconfigurability: Liquid metals are capable of encoding information (e.g., logical on/off, [56] fluidic open/closed, [62] electrically conducting/insulating, [61] optically passing/blocking [192] ) in bistable states, which are switchable through actuation (Figure 8C). Higherorder manipulation beyond bistability is possible and can be achieved in a magnetic field.…”

“…• LM logic gates can be created from combinations of binary LM switches [ 191] (Figure 9J). and Table 9) by analyzing the role of liquid metals for each particular task.…”

“…This process is similar to traditional field-effect transistors, in which an electrical control signal at the gate alters the conductivity between the source and drain. Similar to transistors, which are the fundamental building block for logic cir-cuits, computer memory, and microprocessors, the bistability in liquid metals make them a promising candidate for logic and computation, which is shown as a pure electrical switch [56] (Figure 9G), a transistor-like device [61] (Figure 9K), and higherlevel logic gates [191] (Figure 9J).…”

A Data‐Driven Review of Soft Robotics

“…[580,581] Metallic reactions also facilitate the use of chemical media as a mode of locomotion in liquid metals. [582,583] Chemical-driven processes, such as combustion, [533,584] have been explored more deeply since we initially conducted our analysis. Another exciting new publication discusses the Marangoni effect as a propulsion mechanism utilizing a surface tension gradient generated by the release of alcohol into the water on which a robot locomotes.…”

“…As discussed below, untethered devices appear to be much more achievable with an onboard power source. Recent research exemplifies this notion with three different approaches: a combustion-driven jumping robot that chemically creates its own hydrogen fuel from liquid metal, [584] a battery that can stretch and also bend at a radius of curvature of 10 mm, [598] and a soft robot that traverses across the surface of water propelled by a surface tension gradient via alcohol released from an onboard porous medium. [585] Figure 6b shows a majority of physical tethering for all component types except a power-providing robotic component.…”