Multi-degree-of-freedom (DoF) actuation can greatly expand the versatility of soft actuators. However, existing multi-DoF soft actuators often suffer from slow responses, poor energy efficiency, and exponentially increased complexity in nonlinear dynamics, which hinder their applications in practical tasks. 

Recently, a research team led by Dr. CAO Chongjing from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences (CAS) developed a novel bio-inspired soft actuator that can output programmable two-dimensional quasi-static and resonant trajectories through the coordinated actuation of four dielectric elastomer units. This two-dimensional trajectory programmable soft actuator design significantly expands the versatility of soft actuators while maintaining the benefits of optimized power output from resonant actuation. 

This study was published in Advanced Intelligent Systems on March 1^st and was selected as the back cover (issue 5, volume 6) of the journal.  

The bio-inspired soft actuator consists of four independently powered dielectric elastomer units forming a cross configuration. By solving the accurate kinematic and dynamic model of this actuator, an actuation voltage programming algorithm was developed to realize precise mapping between the target output trajectories and the required actuation voltage sequences. 

To showcase the two-dimensional trajectory programming capabilities of the proposed bio-inspired soft actuator, a demonstration of writing the Chinese characters “Zhong Hua” within a 0.5-millimeter square was developed. In addition to precise trajectory following on the submillimeter scale, the researchers also demonstrated the capability of generating rapid (~50 Hz) and large stroke flapping patterns mimicking hummingbirds in nature using the proposed actuator. 

"Our team is dedicated to the fundamental studies of high-performance electroactive soft actuators, including novel mechanisms and nonlinear dynamics," said Dr. CAO. "We are also pushing hard on the novel applications of such soft actuators in the field of biomedical engineering and bio-inspired robotics." 

The proposed design is expected to have wide applications in bio-inspired robotics by mimicking the diverse motions found in their natural counterparts. (Image by SIAT)

Media Contact:
ZHANG Xiaomin
Email:xm.zhang@siat.ac.cn