Public Release: 

New computational method provides optimized design of wind up toys

New approach unveiled at ACM SIGGRAPH Asia

Association for Computing Machinery

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IMAGE: Wind-up mechanism of Angry Bird constructed by the researchers' method (left), 3-D printed wind-up toy (right). The method constructs and optimizes a compact and lightweight internal wind-up mechanism to realize... view more 

Credit: Courtesy of ACM SIGGRAPH Asia 2017

A team of leading computer scientists has developed a novel computational system to aid the design and fabrication of wind-up toys, focusing on automating the intricate interior machinery responsible for the toys' wind-up motion. The new computational system includes analytic modeling of a wide variety of elemental mechanisms found in common wide-up toys, including their geometry and kinematics, and automating the construction of the toys accurately and with moving parts that consume less energy.

The researchers, from University of Science and Technology of China, the Chinese University of Hong Kong and University College London, will present their work at SIGGRAPH Asia 2017 in Bangkok, 27 November to 30 November. The 10th annual conference and exhibition will showcase some of the world's leading professionals, academics and creative minds at the forefront of computer graphics and interactive techniques.

Wind-up toys are typically lightweight with compact internal mechanical assemblies that are powered by clockwork motors attached to a spring key. Once the toy is wound up and the interior spring is released, the stored potential energy drives the toy's internal mechanical parts, which then prompts the additional parts of the toy to perform their specified motions, like swinging arms, a moving tail, a bobbing head, for example. The interior assembly often consists of small mechanical parts of nontrivial shapes. These parts have to compactly stay within the toy's body shell and connect to each other with minimal friction for efficient motion transfer, making wind-up toys difficult to design manually.

"In the era of personalized fabrication like 3-D printing, we asked, why can't novices still design customized wind-up toys?" said Dr. Peng Song, a former associate researcher of University of Science and Technology China and a lead author of the research. "We set out to computationally design these expressive toys with moving parts but requiring low energy."

Detailed in the paper, the researchers identified 11 elemental mechanisms commonly found in wind-up toys--fundamental motion patterns such as swinging while moving or bobbing up and down while bumping right to left--and modeled their geometry, kinematic properties, and connections. Given user inputs such as toy parts, motion range and motor pose, the team's new method automatically constructs and arranges the mechanical parts inside the toy for delivering the desired toy motion. The researchers optimized the geometry of the wind-up mechanism by aiming to compact the mechanism, minimize its weight, avoid collision between any internal parts with the spring motor and body shell, and assure the desired motion of the toy is achieved.

Novices were able to successfully design their own wind-up toys using the new computational system. The designs were 3-D printed to test the functionality of the new model. Using a prototype--a wind-up toy teapot--the researchers showed that their computer-aided design resulted in a more compact mechanism with smaller mechanical parts, and the ability to run motions for longer durations and move over a longer distance. Down the road, the researchers plan to explore the use of their methods on micro-robot design and mechanical toys that run on limited battery power.

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"Computational Design of Wind-Up Toys" is coauthored by Peng Song, Xiaofei Wang, Xiao Tang, Hongfei Xu and Ligang Liu of the University of Science and Technology of China; Chi-Wing Fu of the Chinese University of Hong Kong; and Niloy J. Mitra of University College London.

For the full paper and presentation video, visit the project page.

About SIGGRAPH Asia 2017

The 10th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia will take place in Bangkok, Thailand at the at the Bangkok International Trade and Exhibition Centre (BITEC) from 27 - 30 November 2017. The annual event held in Asia attracts the most respected technical and creative people from all over the world who are excited by research, science, art, animation, gaming, interactivity, education and emerging technologies. The four-day SIGGRAPH Asia 2017 conference includes a diverse range of juried programs, such as the Art Gallery, Computer Animation Festival, Courses, Emerging Technologies, Posters, Symposium on Education, Symposium on Mobile Graphics and Interactive Applications, Symposium on Visualization, Technical Briefs, Technical Papers, VR Showcase and Workshops. A three-day exhibition held from 28 - 30 November 2017 will offer a business platform for industry players to market their innovative products and services to the computer graphics and interactive techniques professionals and enthusiasts from Asia and beyond.

About ACM SIGGRAPH

The Association of Computing Machinery's Special Interest Group on Computer Graphics and Interactive Techniques (ACM SIGGRAPH) sponsors SIGGRAPH Asia 2017. Founded in 1947, ACM is an educational and scientific society uniting the world's computing educators, researchers, and professionals to inspire dialogue, share resources, and address the field's challenges. ACM strengthens the profession's collective voice through strong leadership, promotion of the highest standards, and recognition of technical excellence. The ACM SIGGRAPH deals with all aspects of graphical user/computer communication and manipulation: hardware, languages, data structure, methodology, and applications

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