Abstract: Plants offer a rich source of bioinspiration for robot design that has, up to this point, not been extensively explored. These natural systems have an incredible ability to access difficult to reach areas while remaining flexible and responsive to their environments; think of a blade of grass strong enough to poke through the sidewalk but flexible enough to spring back when stepped on. In my work, I investigate one particular type of plant-inspired soft robot, called vine robots, that can effectively grow from the tip using eversion of pressurized material, moving independent of the environment and creating a structure along the grown path. In this presentation, I will show how plant inspired growth can allow new ways of moving through and interacting with the world. I will start by answering the question of what it means to grow as a robot, showing the basic behaviors and models underlying growth and how this behavior allows growing robots to access sticky, slippery, or otherwise hostile environments. I will then show how simplified geometric modeling can be leveraged to create the forward and inverse kinematics for growing robot steering, allowing us to actuate the shapes needed for a task. Finally, I will discuss how we can leverage the natural interactions of vine robots with obstacles to decrease steering uncertainty and to achieve proprioceptive and extero-sensing with minimal sensors.

Abstract: Medical implants have long been designed using traditional methods, relying on multiple parts, rigid components, and sliding surfaces due to their predictability and familiarity. Compliant mechanisms, devices that use mechanical compliance to obtain motion, offer opportunities to reimagine the underlying science behind medical implant design to create systems that are more compatible with the musculoskeletal system. A systematic review of existing technology in the literature has provided a roadmap for areas of impact in the field of orthopedic implants. These principles can then be extended to the development of patient-specific, bio-emulative devices that can improve post-operative recovery.

Because of the spatially constrained environment within which medical devices operate, inspiration for future device development can also be informed by and inspire the development of other space-constrained devices. This presentation will also discuss how the evolution of developable mechanisms, devices that conform to and deploy from particular curved surfaces, may serve as an enabling technology for medical devices, planetary science robotics, and space-based applications.

Abstract: Co-robots allow the full use of human’s intelligence and robots’ precision and strength to improve the combined performance as a team in various scenarios including manufacturing, logistics, military, medical care, home companion and others. A fundamental challenge for the development of co-robots has been finding a balance between high performance and high safety for human interaction. With respect to rigidity, achieving high performance (high accuracy and payload) often relies on high stiffness co-robots, while safe interactions with humans often requires low stiffness. This has led to the development of variable stiffness actuators (VSAs) which can change the stiffness levels between low and high. This talk will present a concept of discrete variable stiffness change principle to develop new VSAs, named DVSAs, for fast stiffness change and low energy consumption through representative stiffness levels. Recently developed DVSAs and their design methods will be presented and extended to compliant manipulators, grippers and mechanisms.

Abstract: Polynomial homotopy continuation has proven to be an effective technique for solving equations associated with kinematic synthesis. Such techniques help better inform decisions on the geometries of robots to improve their motion capabilities and energetic characteristics. The constituent equations involved naturally take polynomial form, and possess a large, but finite number of zeros. The success of polynomial homotopy continuation is due to its numerical nature, its ability to find (nearly) all zeros, and its computational scalability. This talk covers advancements in scalability, new directions related to the role of homotopy in optimization, and challenges related to numerical precision that limit the practical value of these algorithms.