publications

2021

1. The design and development of Branch Bot: a branch-crawling, caterpillar-inspired, soft robot

   Rozen-Levy, Shane, Messner, William, and Trimmer, Barry A

   The International Journal of Robotics Research Jan 2021

   Abs

   A soft climbing robot has the potential to access locations such as wiring ducts and tree canopies that are unreachable by humans and traditional rigid robots. In addition, a soft robot is robust and can fall without damaging itself or its environment. We present a soft, branch-crawling robot that is inspired by the passive gripping mechanisms used by caterpillars. The conformability of the robot’s soft body makes it uniquely suited to move in a complex 3D environment. A key innovation is that grip release is actively controlled and coordinated with propulsion generated by stored elastic energy. The robot is molded from silicone rubber and actuated using remote motor-tendons coupled to the structure through Bowden cables. Grip is achieved passively through an elastic flexure that pushes a compliant finger against the dowel. Experimental results show that the gripper is easily able to support the weight of the robot, and that the body structure allows the robot to crawl horizontally, vertically, and along branches. This robot demonstrates some key advantages of a soft robotic platform over traditional rigid robots.

2018

1. Functional Safety Assessment of an Automated Lane Centering System

   Becker, Christopher, Yount, Larry, Rozen-Levy, Shane, Brewer, John, and John A. Volpe National Transportation Systems Center (U.S.),

   Aug 2018

   Abs

   This report describes the research effort to assess the functional safety of a generic automated lane centering (ALC) system,. a key technology that supports vehicle automation by providing continuous lateral control to keep the vehicle Within the travel lane. This study follows the Concept Phase process in the ISO 26262 standard and applies hazard and operability study, functional failure modes and effects analysis, and systems-theoretic process analysis (STPA) methods. This study identifies 5 vehicle-level safety goals, 47 functional safety requirements (an output of the STPA process) for the ALC system, and 26 additional safety requirements (also an output of the STPA process) for the ALC system based on the results of the safety analysis. This study also uses the results of the analysis to develop potential test scenarios and identify possible areas for diagnostic trouble code coverage.

2017

1. Passive gripper inspired by Manduca sexta and the Fin Ray® Effect

   Crooks, Whitney, Rozen-Levy, Shane, Trimmer, Barry, Rogers, Chris, and Messner, William

   International Journal of Advanced Robotic Systems Jul 2017

   Abs

   Soft robotic grippers are advantageous for tasks in which a robot comes into close contact with a human, must handle a delicate object, or needs to conform to an object. Most soft robotic grippers, like their hard counterparts, require actuation to maintain a grip on an object. Here, we present a passive, soft robotic gripper that requires power to open and close but not to maintain a grip, which can be problematic in environments with limited energy availability (e.g. solar or battery power). Passive grip, by not requiring power to maintain grip on an object, provides a unique and safe alternative to energy-limited or energy-scarce environments. The Tufts Passive Gripper was inspired by the passive grip of the Manduca sexta and the simplicity of the Fin Ray® Effect. The gripper can be three-dimensional printed as one part on a multimaterial three-dimensional printer and only requires four additional steps to install the motor/tendon actuation mechanism. The gripper was capable of picking up over 40 common household objects, including a tissue, a pen, silverware, a needle, a stapler, a cup, and so on. The maximum load a gripper could hold when oriented perpendicular and parallel to the ground was 530 g (1 lb) and 240 g (0.5 lb), respectively.

2. Soft foam robot with caterpillar-inspired gait regimes for terrestrial locomotion

   Donatelli, Cassandra M., Serlin, Zachary T., Echols-Jones, Piers, Scibelli, Anthony E., Cohen, Alexandra, Musca, Jeanne-Marie, Rozen-Levy, Shane, Buckingham, David, White, Robert, and Trimmer, Barry A.

   In 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) Sep 2017

   Abs

   Caterpillars are the soft bodied larvae of lepidopteran insects. They have evolved to occupy an extremely diverse range of natural environments and to locomote in complex three-dimensional structures without articulated joint or hydrostatic control. These animals make excellent bio-inspiration for the field of soft robotics because of their diversity and adaptability. In this paper, we present SquMA Bot, a caterpillar-inspired soft robot. The robot’s body is primarily composed of a soft viscoelastic foam, and it is actuated using a motor-tendon system. SquMA Bot is able to mimic the inching gait of a caterpillar and can use its flexible body to adapt to a range of environments. This bio-inspired prototype demonstrates the effectiveness of a soft robot as a potential tool for exploring environments too dangerous for humans.