2021 Winners & Finalists

Graduate Category Winners

An In-situ Collaborative Robot for Manufacturing in Confined Spaces

Andrew L. Orekhov, Garrison L. H. Johnston, Colette Abah, Vanderbilt University

(1st Place Winner)

Some manufacturing tasks require workers to operate in confined spaces, which can be dangerous due to a lack of access and are physically demanding for workers due to unergonomic postures. A collaborative robot could alleviate these burdens, but existing robotic systems are not suitable for this application due to a lack of ability to reach deep into confined spaces and a lack of passive and active safety measures. In this project, we present an in-situ collaborative robot that seeks to address the unique challenges of collaborative manufacturing in confined spaces. The design consists of statically-balanced revolute joints for improving load-carrying capacity and passive safety, continuum segments with modular tendon actuation for enhanced dexterity, and multi-modal sensing disks to enable mapping of the environment, contact localization, and physical interaction with the robot. We present the mechanical design and analysis of these design features as well as their integration with the robot’s sensing and control electronics.

A High Precision Mirror Symmetric XY Positioner

Jiaxiang Zhu, University College Cork

(2nd Place Winner)

This project presents a new XY compliant positioner using mirror-symmetry without increasing its footprint, mainly aiming to reduce the undesired parasitic rotations of input and output motion stages. In an XY compliant positioner, the parasitic motion refers to the in-plane rotational yaw of a rigid stage, which is inherent with the primary motion that must be suppressed by design since it can not be compensated by control. The concept of higher degree of stiffness centre symmetry is deployed to tackle the parasitic rotations, leading to a multi-layer compact XY positioner design with each layer being a rotation-symmetrical design. A nonlinear and analytical model of the proposed XY positioner is derived using free body diagrams and the Beam Constrained Model (BCM) to accurately analyse its performance characteristics over a large range of motion. The designed XY positioner is then verified by the nonlinear finite element analysis (FEA) method and a prototype is fabricated for experiment verification. Finally, the proposed multi-layer design is comprehensively compared with the well-received single-layer rotation-symmetrical design. It is shown in the new design that the parasitic rotations of input and output stages along with the actuator isolation are significantly reduced and that the out-of-plane-stiffness is also significantly increased. This XY compliant positioner is expected to be used for medical industry, laser micro-machining, optics and photonics setups and semiconductor metrology where high precision is required.

A Modular, Open-Source Continuum Manipulator for Underwater Remotely Operated Vehicles

Justin Sitler, Stevens Institute of Technology

(3rd Place Winner)

Continuum manipulators are a class of robots with many degrees of freedom, leading to highly flexible motion with natural compliance. These attributes make them well-suited for manipulation tasks and interaction with the environment. However, these robots have been underutilized for mobile robot manipulation. A high impact yet challenging field for exploring continuum robot designs is free-floating underwater manipulation. In this paper, we propose a modular cable-driven continuum robot for free-floating underwater manipulation and present a corresponding kinematics, control, and computation framework. The mechanical design consists of a continuum arm, an actuation unit, and waterproof enclosure. The kinematics model is introduced as two mappings between three spaces: the joint space, the configuration space, and the task space. The differential kinematics for each mapping is also derived.The electronics system design is explained, along with the communication framework between the central computer, on-board electronics, and auxiliary motors and sensors. Future improvements to the design include integration with the free-floating remotely operated vehicle (ROV) platform and development of more advanced controls and planning for specific tasks.

Undergraduate Category Winners

Heavy Lift and Carry Exoskeleton

Hunter Andrieu, Nabra Asgedom, Sarah Bresnahan, Sanghyeon Chang, Bonham Ekleberry, Sara Elnahhas, Nathan Folta, Adam Hinson, John Kuempel, Brita Lyons, Jakob Lyons, Austin Petty, Ben Wardach, Zhao Yu, Virginia Tech, USA

(1st Place Winner)

Repetitive and heavy lifting is one of the leading causes of injury in the workplace. This affects individuals in many industries, but is a distinct problem in manufacturing and logistics settings including stocking, construction, and distribution. The aim of this project is to design a pneumatic full-body exoskeleton suit to be used by any able-bodied person who lifts heavy objects. This will mitigate the risk of injury while allowing them to perform their tasks with reduced physical exertion by artificially increasing their strength and endurance. This team has designed, built, and will test a full-body exoskeleton suit that compensates the weight of an object up to 40 pounds in per arm. This team’s design differs from other industrial exoskeleton designs in that it minimizes the number of actuators present, resulting in reduced cost of production and simplification of the design and control processes.

U5-Video.mp4

Design, Fabrication, and Verification of a Compliant Ankle Rehabilitation Robot (Flex-ARR)

Adam Kim, University of Michigan

(2nd Place Winner)

Flex-ARR is a novel ankle rehabilitation robot that can provide plantarflexion/dorsiflexion and inversion/eversion of the ankle joint for therapeutic exercises. The main intellectual merit of the Flex-ARR is the compliant transmission that mitigates misalignment between the robot’s center of rotation and the user’s center of rotation. Additionally, a novel alignment tool is used during the installation process of the user’s foot into the robot to help further reduce misalignment. Reducing misalignment between the robot’s center of rotation and the user’s center of rotation is critical in preventing reaction loads from potentially overstraining the user’s ankle joint. Special emphasis was given to safety mechanisms and adjustment features in the Flex-ARR design to further improve the safety and comfort of the user during a therapy session.

U1-Video.mp4

Coupled Finger Robot

Jacob Shapiro, University of Notre Dame, USA

(3rd Place Winner)

This robot will closely replicate the motion of a human finger by coupling the movement of the middle and distal linkages. Unless double-jointed, a human cannot independently move the end link of the finger without also moving the middle link. This robot will mechanically replicate this relationship without the use of an additional actuator. Instead, the joint will be constructed as a flexible four-bar mechanism, 3D printed from TPU. Spherical four-bar mechanisms, driven by DC motors, will be used to actuate the other two finger joints. The finger will be fabricated from 3D printed PLA and controlled using an RC controller.

U6-Video.mp4

Graduate Category Finalists

A soft manipulator with variable stiffness, proprioceptive and tactile capabilities

Francesco Stella, TU Delft, Netherlands

I propose a soft robotic manipulator which can show variable stiffness, length change, and complex shape control. The manipulator is based on a tri-tube soft actuation method, and its capabilities are enhanced with a parallel variable stiffness mechanism. Thanks to the variable stiffness mechanism, the robot is able to execute both delicate and high force tasks, which often result unfeasible for soft manipulators. The proposed prototype is manufactured via molding, 3D printing and laser cutting technologies. The robot is modeled and controlled based on a Piecewise Constant Curvature approximation. The robot can sense its pose thanks to encoders and Inertial Measurement Units (IMUs) spread through the body. Hence, the pose is controlled in closed loop, while the stiffness of the tip of the manipulator is controlled in open loop via optimal control techniques. Potential applications range from dexterous manipulation, human robot cooperation to exploration of challenging environments.

Undergraduate Category Finalists

Design and Prototyping of a Novel Transmission Mechanism for a Planar Cable-Driven Parallel Crane without Parasitic Tilt

Lionel ETIENNE, Centrale Nantes, CNRS, LS2N, France

Cable-Driven Parallel Robots (CDPRs) offer high payload capacities, large translational workspace and high dynamics performances. Their rotational workspace is generally far more limited, however, it can be resolved by using cable loops, as was shown in previous researches. In the case of suspended CDPRs, cable loops can induce unwanted torques on the moving platform, causing it to tilt and move away from its intended position, which we call parasitic tilt. Hence, the orientation accuracy of such robots is usually limited. This project deals with the design and prototyping of a novel transmission system to remove the parasitic tilt of a planar CDPR with infinite rotations. This robot, which we call a Cable-Driven Parallel Crane (CDPC), is composed of a mobile platform (MP) with an embedded mechanism and a transmission module to control the added cable. The MP is linked with the frame by a parallelogram composed of three cables to constrain its orientation, including a cable loop, as well as a fourth cable. The two-degree-of-freedom (dof) motions of the moving-platform of the CDPC and the internal dof of its embedded mechanism are actuated by a total of three actuators, which are fixed to the frame. As a consequence, the overall system is fully-actuated, its total mass and inertia in motion is reduced and it is free of parasitic tilts.

4CablesTraj1c.mp4

Mechanical Actuation via Resorbable Materials

Bethany Parkinson, Corinne Jackson, and Clark Roubicek, Brigham Young University

Mechanical systems often require gradual or delayed actuation for complete functionality. Typical actuation methods use electrical systems and require the use of a micro- controller with a timer. A novel and passive means for gradual or delayed actuation is the use of resorbable materials, which are materials that gradually dissolve or resorb when subjected to a certain solvent. This method is predictable, highly tailorable, and requires no additional energy input to catalyze task completion. Resorbable materials—particularly bioresorbable materials—are widely researched and used. They are desirable materials for resorbable stents or other static implants or stabilizers for implants [1, 2]. However, they are not currently used as a primary method of actuation for mechanical devices. As resorbable materials erode, they lose both mass and volume, leading to a loss in mechanical strength. This change in shape and strength may be leveraged in a device to change the device’s configuration or mechanical properties and therefore to actuate the device. This use of resorbable materials allows for previously impossible applications of mechanisms and proves promising for devices that must be embedded or implanted out of reach of further manipulation. For example, utilizing bioresorbable materials to activate medical devices—e.g. self-adapting corrective implants—allows for minimally-invasive, more gradual, and less painful in vivo corrective procedures.

Resorbable_VideoSubmission.mp4

Octopod Robot

Kyle Barry and Richard Hume, University of Notre Dame, USA

The goal of this project was to create an 8-legged walking robot that utilizes a highly sensitive 6-bar walking mechanism that was invented by the advising professor. The purpose in creating an 8-legged walking robot was to demonstrate the ability and effectiveness of the walking mechanism while maintaining the greatest stability and ease of control of the robot. The robot is controlled remotely through the use of a BeagleBoneBlue and power is transmitted through timing belt and pulley systems that are driven by a single motor for each side of the robot. It is our goal to enable differential turning and zero radius turning abilities in the robot. In proving the effectiveness of the walking mechanism, our hope is to be able to create a variety of different robots that may feature fewer legs or altered foot designs that will optimize the robots for different tasks such as running or traversing over uneven terrain.

U8-Video.mp4

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