NASU -- Novel Actuating Screw Unit: Origami-inspired Screw-based Propulsion on Mobile Ground Robots

TL;DR

This paper introduces NASU, a reconfigurable screw-based propulsion system inspired by origami, enabling dynamic adjustment of the angle of attack to optimize locomotion across diverse terrains for mobile robots.

Contribution

The paper presents the first screw propulsion design with adjustable angle of attack, allowing real-time optimization for different media and mission objectives.

Findings

Trade-off observed between efficiency and velocity based on angle of attack.

NASU demonstrates effective locomotion in gravel, grass, and sand.

Reconfigurable screw design enhances adaptability for mobile robots.

Abstract

Screw-based locomotion is a robust method of locomotion across a wide range of media including water, sand, and gravel. A challenge with screws is their significant number of impactful design parameters that affect locomotion performance. One crucial parameter is the angle of attack (also called the lead angle), which has been shown to significantly impact the performance of screw propellers in terms of traveling velocity, force produced, degree of slip, and sinkage. As a result, the optimal design choice may vary significantly depending on application and mission objectives. In this work, we present the Novel Actuating Screw Unit (NASU). It is the first screw-based propulsion design that enables dynamic reconfiguration of the angle of attack for optimized locomotion across multiple media and use cases. The design is inspired by the kresling unit, a mechanism from origami robotics, and the angle of attack is adjusted with a linear actuator, while the entire unit is spun on its axis to generate propulsion. NASU is integrated into a mobile test bed and experiments are conducted in various media including gravel, grass, and sand. Our experiment results indicate a trade-off between locomotive efficiency and velocity exists in regards to angle of attack, and the proposed design is a promising direction for reconfigurable screws by allowing control to optimize for efficiency or velocity.