Advancing Soft Robotics: A High Energy-Efficient Actuator Design Using Single-Tube Pneumatic for Bidirectional Movement

Abstract

Soft robotics offers unprecedented adaptability and safety in human–machine interactions but faces challenges in achieving energy-efficient bidirectional movement with simplified pneumatic systems. This study introduces an innovative soft pneumatic actuator design concept with high efficiency inspired by inchworm locomotion, featuring a single air pathway for bidirectional control. The design utilizes a unique 45 deg sloped tail and strategically placed contact areas, enabling efficient bidirectional movement through a stick-slip mechanism controlled by modulating air pressure and actuation frequency. The study demonstrates a 31.2% reduction in internal energy consumption and a 36.4% improvement in energy-to-motion efficiency compared to conventional designs with complicated structures. New metrics, including the energy efficiency ratio (EER), internal energy, kinetic energy, and bending efficiency (BE), are introduced to evaluate actuator performance. The study reveals an exponential relationship between bending angle and length to height (L/H), with θmax of 71 deg at the lowest L/H ratio. Rigorous testing across diverse surface conditions validates the efficiency of the approach, with the actuator demonstrating consistent performance on surfaces with static friction coefficients ranging from 0.3 to 1.7. Analysis of bending dynamics, velocity characteristics, and energy consumption across various pressure ranges (100–400 kPa) and frequencies (1/8 Hz to 1.0 Hz) provides a framework for fine-tuning soft actuators. This research contributes to the design of energy-efficient soft robotics, paving the way for more adaptable and energy-conscious systems with potential applications in medical devices, industrial manipulators, and confined space exploration.