Power Amplification for Jumping Soft Robots Actuated by Artificial Muscles.

Adriane Fernandes Minori,Haojin Chen,Saurabh Jadhav,Samantha Fong,Michael T Tolley

doi:10.3389/frobt.2022.844282

Abstract

Robots composed of soft materials can passively adapt to constrained environments and mitigate damage due to impact. Given these features, jumping has been explored as a mode of locomotion for soft robots. However, for mesoscale jumping robots, lightweight and compact actuation are required. Previous work focused on systems powered by fluids, combustion, smart materials, electromagnetic, or electrostatic motors, which require one or more of the following: large rigid components, external power supplies, components of specific, pre-defined sizes, or fast actuation. In this work, we propose an approach to design and fabricate an electrically powered soft amplification mechanism to enable untethered mesoscale systems with continuously tunable performance. We used the tunable geometry of a liquid crystal elastomer actuator, an elastic hemispherical shell, and a pouch motor for active latching to achieve rapid motions for jumping despite the slow contraction rate of the actuator. Our system amplified the power output of the LCE actuator by a factor of 8.12 × 103 with a specific power of 26.4 W/kg and jumped to a height of 55.6 mm (with a 20 g payload). This work enables future explorations for electrically untethered soft systems capable of rapid motions (e.g., jumping).

Highlights

Soft robots—i.e., robots composed primarily of soft materials—have the potential to be more adaptable, conformable, and resilient than their rigid counterparts (Rus and Tolley, 2015)
We propose an approach to the design and fabrication of a modular soft robot with a mechanism for amplifying the power output of artificial muscles to achieve rapid motions using a motor-spring-latch design (Figure 1)
The height of the top cap can be assigned as a design constraint since the weight of the top cap increases with the geometry of the Liquid Crystal Elastomer (LCE) and shell, and overall increasing the size required for a mesoscale jumping robot

Summary

Introduction

Soft robots—i.e., robots composed primarily of soft materials—have the potential to be more adaptable, conformable, and resilient than their rigid counterparts (Rus and Tolley, 2015). Previous actuation methods for soft jumping robots used pneumatic actuation (Gorissen et al, 2020), chemical combustion (Tolley et al, 2014b; Bartlett et al, 2015), or high-voltage artificial muscles (Duduta et al, 2019) that required either large rigid components or heavy external power supplies. Another challenge of soft jumpers is the trade-off between weight and speed, given their dependency on the size of the system and its actuation. Variable actuation speeds, and can be triggered by different stimuli (e.g., light, magnetism, moisture)

Methods

Results

Conclusion