New Simulation Tool for Mimicking Movements of Soft, Limbed Robots

At present, video games and motion picture animation are magnificently lifelike, capturing a canvas sail that snaps crisply in the wind or a wisp of hair that falls across the eyes of a heroine.

Researchers from the University of California, Los Angeles (UCLA) and Carnegie Mellon University have employed this advanced computer graphics technology to mimic, for the first time, the movements of soft robots with limbs.

The study outcomes were reported in a paper titled, “Dynamic Simulation of Articulated Soft Robots,” published in Nature Communications on May 6^th, 2020.

“We have achieved faster than real-time simulation of soft robots, and this is a major step toward such robots that are autonomous and can plan out their actions on their own,” stated study author Khalid Jawed, an assistant professor of mechanical and aerospace engineering at UCLA Samueli School of Engineering.

Soft robots are made of flexible material which makes them intrinsically resilient against damage and potentially much safer in interaction with humans. Prior to this study, predicting the motion of these robots has been challenging because they change shape during operation.

Khalid Jawed, Assistant Professor of Mechanical and Aerospace Engineering, UCLA Samueli School of Engineering

An algorithm known as discrete elastic rods (DER) is often used in movies to animate free-flowing objects. Within a second, DER can predict hundreds of movements. The team intended to develop a physics engine using DER, with the ability to mimic the movements of bio-inspired robots and robots in difficult environments, like the surface of Mars or underwater.

Finite elemental method (FEM), another technology based on algorithms, can mimic the movements of rigid and solid robots. However, it is not well-equipped to handle the complexities of soft, natural movements. Moreover, it needs considerable computational power and time.

To date, roboticists have employed a laborious trial-and-error method for analyzing the dynamics of soft material systems, as well as for designing and manipulating soft robots.

According to Carmel Majidi, an associate professor of mechanical engineering at Carnegie Mellon’s College of Engineering, “Robots made out of hard and inflexible materials are relatively easy to model using existing computer simulation tools.”

Until now, there haven’t been good software tools to simulate robots that are soft and squishy. Our work is one of the first to demonstrate how soft robots can be successfully simulated using the same computer graphics software that has been used to model hair and fabrics in blockbuster films and animated movies.

Carmel Majidi, Associate Professor of Mechanical Engineering, College of Engineering, Carnegie Mellon University

The researchers began their collaborative work in Majidi’s Soft Machines Lab over three years ago. As a continuation of their teamwork in this recent study, Jawed performed the simulations in his lab at UCLA and Majidi conducted the physical experiments that confirmed the simulation results.

The study was partially funded by the Army Research Office.

Experimental advances in soft-robotics have been outpacing theory for several years. This effort is a significant step in our ability to predict and design for dynamics and control in highly deformable robots operating in confined spaces with complex contacts and constantly changing environments.

Dr Samuel Stanton, Program Manager, Army Research Office

The Army Research Office is an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory.

At present, the researchers are making efforts to use this technology for soft robots of other types, like the ones inspired by the movements of starfish and bacteria. Swimming robots such as those could be completely untethered and employed in oceanography to track seawater conditions or investigate delicate marine life status.

The new simulation tool can considerably bring down the time required to translate a soft robot from the drawing board to application. Although robots still have a long way before they can match the capabilities and efficiency of natural systems, researchers can use computer simulations to bridge this gap.

Weicheng Huang from UCLA and Xiaonan Huang from Carnegie Mellon are the co-first authors of the paper.

Journal Reference:

Huang, W., et al. (2020) Dynamic simulation of articulated soft robots. Nature Communications. doi.org/10.1038/s41467-020-15651-9.