DIMLab Stander Symposium Projects

2020

Soft Robot Actuator Design for Digital Light Processing

Dillon Balk

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This research involves the design, simulation and fabrication of novel soft robot actuators. Since the 1970s, robot design engineers have been experimenting with soft materials in robotics components. Inspired by natural organisms, “soft robotics” involves the integration of a soft polymer material into a mechanism in order to achieve a variety of configurations. Pneumatically actuated by air through hollow channels within, a soft robotics component allows for very large, non-linear, displacements compared to classical rigid body components. These attributes allow soft robotics to have potential biomedical, industrial, and rescue applications. This research project involves designing and simulating various soft robotic actuators to mimic primitive motions, including twisting, bending, elongating, and angular displacement. The various actuators can be assembled to form serial and parallel chains to perform basic robotic tasks, such as search-and-retrieval or pick and place operations. Digital light processing (DLP) technology is an appealing fabrication technique because it is able to create very intricate parts with high resolution. Utilizing UDRI’s DLP capabilities, experiments with physical prototypes will calibrate and validate the simulation results.

Design of a Trike for Paraplegics Powered By Functional Electrical Stimulation of Leg Muscles

Anthony Bazler & Nick Lanese

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The goal of this project is to design a performance tricycle for paraplegics whose leg muscles are stimulated to pedal via Functional Electrical Stimulation (FES). FES stimulates muscle contraction with small electrical currents and has proven useful in building muscle in patients while relieving soreness and promoting cardiovascular health. An FES-stimulated cyclist produces approximately 25 Watts of power, nearly 20 times less than a typical rider. At these reduced power levels, the challenges of pedaling are amplified. For example, as the pedal follows the traditional circular path, there are portions referred to as dead zones, where neither FES-stimulated leg actively propels the bike forward. One possibility for reducing or eliminating dead zones is to redesign the circular path of the pedaling motion. Bicycles have recently been marketed that feature pedaling mechanisms that employ alternate pedaling motions. In addition to addressing dead zones, these bikes also optimize the muscle capacity of the rider to deliver torque to the wheels. These new bikes achieve alternate pedaling paths through the introduction of more complicated mechanisms including four-bar and ratchet-and-pawl linkages. Such alternates are being considered for the redesign of the performance tricycle piloted by FES-stimulated riders. To investigate possible changes to the tricycle, quasi-static models have been developed for traditional and alternate cycling mechanisms. This allows for a comparison of torque generation between the mechanisms which facilitates selecting the optimal design. Such a tricycle is viewed as beneficial due to the health advantages, improved mobility, and independence created for the end user.

A Novel Approach to Design Planar Four-Bar Linkages for Approximation Motion Synthesis

Yizhen Cai

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A planar four-bar linkage can be synthesized to achieve at most five positions. Most useful design problems involve many more positions than this with the expectation that the four-bar mechanism will not accomplish the task exactly but will be close. Several methodologies have been proposed in the literature for solving this approximate motion synthesis challenge. Each of these methodologies has a metric central to it. This metric measures how well the mechanism performs at reaching the positions. As each methodology has its own metric, each produces a different optimal design. This research proposes a way to design a four-bar linkage for approximate motion synthesis that does not rely on a position metric. Not only does this produce a unique best solution, but it also provides a method for evaluating other approaches to solve the problem.

A Fast Algorithm for Solving the Kinematics of Hyper Redundant Robots

Tiangang Chen

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Hyper redundant robots consist of many equal length rigid links connected by a large number of revolute joints. This significant number of joints gives the robot many degrees of freedom enabling it to function in highly constrained environments. This work introduces a methodology to solve the kinematics of a hyper redundant robot. Addressing the kinematics includes two issues. The first issue is to approximate a desired curve that specifies the configuration or shape of the robot. The second issue is to accurately position the tool at the end of the robot. These two issues are addressed by analyzing the desired curve describing the hyper redundant robot as piecewise linear similar to the analysis for generating target profiles in shape-changing mechanism theory. There are two advantages to this approach. First, the error will be small. Second, the speed of the calculation is fast.

Automated Design of Truss-Based Mechanical Components Using Topology Optimization

Robert McCarren

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The goal of this research is to develop a design strategy, and associated algorithms, that take advantage of the topology optimization package within SolidWorks to create easily producible parts. Topology optimization (TO) is a numerical procedure that accepts an initial design space, which includes loads and constraints, and produces a part optimized for structural performance. The optimization objective is commonly posed as maximizing rigidity based on a desired weight percentage, subject to maximum stress and other design constraints. One difficulty with commercial packages, such as SolidWorks, is that the final designs are generally difficult to manufacture without using additive manufacturing (AM) due to the organic nature of the TO results. AM is impractical for many applications and the TO results must be converted to a practical design using conventional manufacturing operations. A consistent method for converting the TO results into manufacturable parts does not exist. Experienced design engineers can produce considerably different practical designs from the TO results. This research focuses on automating the conversion from TO results to practical design using visual basic coding in SolidWorks. TO results will generally resemble truss-like shapes due to the strong nature of trusses. As such, the code produces a three-dimensional sketch of the truss from a Matlab visual processing of the TO result and then uses the weldment tool to create the truss geometry with tubing so the part can be more easily produced by conventional methods.

Designing Fictional Spaces: Questionable Architecture that Supports Sustainable Design

Noel Michel

Not presented as a poster.

This thesis presents the modeling of spaces described in short stories that are difficult to visualize. The three stories are Kafka's "The Burrow", Borges's "The Library of Babel" and Barthelme's "The Balloon." Three dimensional models were created based on the details provided by the authors in each story. Several 2-D images are then generated from these models to match specific scenes. This consideration of these works of fiction provokes the asking of several questions about the science, mathematics and engineering that underpins the stories. In all cases, questions about sustainability arise.

Assessment of the Structural Suitability of Tensegrity Aircraft Wings

Austin Mills

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This research investigates the suitability of tensegrity aircraft wing concepts and compares their simulated structural performance to a baseline conventional wing structure. Tensegrity systems consist of a series of compressed struts connected by tensioned cables that place the system in a self-equilibrium state. With all components being loaded axially, a tensegrity system has a potentially high strength-to-weight ratio. Of specific interest, tensegrity systems may provide pathway to morphing aircraft structures through the actuation of cables. Aircraft with wings that are able to alter their sweep, span, chord, and camber are particularly attractive for their ability to change between high maneuverability to high lift to low drag configurations. With an eye towards this application, the present study compares two tensegrity-based wing designs, generated through designer insights and structural topology optimization methods, to the aluminum Van’s RV-4 aircraft rib/spar wing structure, chosen as the baseline performance case.

Optimization of Solar Array Positioning Actuators for Small Satellites

Mohamed Mohamed

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The goal of this research is to evaluate the benefit of actuating solar arrays for small satellites. CubeSats are small satellites that are built to standard dimensions (Units or “U”) of 10 cm x 10 cm x 10 cm. They can be 1U, 2U, 3U, or 6U in size, and weigh less than 1.33 kg (3 lbs) per U. Since their introduction in 1999 by California Polytechnic State University and Stanford University engineers, more than 1100 have been deployed into orbit. CubeSats rely solely on a solar array to generate energy from the sun. The size and weight limitations place constraints on solar panels' size and thus the available power budget and stored energy reserves, which decrease the CubeSat functions. The CubeSats capabilities could be greatly enhanced by increasing the available on-board power. This research determined the energy capturing capability from various solar panel configurations and positioning. Optimal angles of one and two degree-of-freedom positioning. Each configuration of solar cell is simulated for a CubeSats satellite in geo-synchronous and sun-synchronous orbits. In addition, this research will create design models of these various mechanisms configurations by using Sarrus linkage mechanism that elevates the solar cell away from the body of the satellite to make sure that these configurations are suitable for the size and weight of the CubeSat.

Design Modeling of Spatial Shape-Change Linkages

Chengwei Shi

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The goal of this research is to develop mechanical designs of spatial shape-changing linkages. Mechanical systems often benefit from the capacity to vary between specific shapes in a controlled manner, such as a morphing aircraft wing that can adapt to different in-flight requirements. Spatial shape-changing linkages consist of a chain of three-dimensional bodies connected with ball joints. When the chain segments are repositioned, they match a set of arbitrary spatial curves. These chains are composed of two segments types: a twisted rigid segment and a helical segment with constant curvature and torsion but varying length. The research project involves creating the mechanical designs of the segments and motion control schemes that move the chain from the origin position to the target position. Animations are created in SolidWorks that demonstrate various motion schemes and illustrate the chain’s approximation to the target spatial curves.

DIMLabyrinths: Printable 3D Cube Mazes

Adam Wicks

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DIMLabyrinths are 3-dimensional marble mazes designed for 3D printing. The maze body is a cube with an evenly-spaced grid of round holes from top-to-bottom, left-to-right, and front-to- back. The holes are one of two sizes inside the cube, either too small for the marble to pass through or just big enough to allow the marble passage. As such, the solver can see the marble at all times as it moves through the maze embedded in the cube. The design of the maze itself is generated using an algorithm developed in MATLAB. The maze is guaranteed to visit every location in the cube on a path that connects the top-front-left corner to the bottom-back-right corner. This unique geometry is well-suited for manufacturing via 3D printing. DIMLabyrinth files suitable for rapid prototyping are available for free download on the DIMLab My Mini Factory site. The result is a unique puzzle, partially designed in MATLAB, that can be 3D printed at home for free.

Dimensioning Mechanical Press Architecture for Improved Dwell using Advanced Algebraic Techniques

Tianze Xu

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A mechanical press is a machine that shapes parts by driving a ram into metal and deforming the material into a desirable shape. As this is an incredibly common process for forming metal parts, from pop cans to car fenders, presses see significant use in industry. This research project seeks to develop a numerical algebraic method for determining mechanical press dimensions from a desired dwell displacement pattern. This dwell pattern occurs when the ram lingers near the bottom of the stroke while the rest of the press stays in motion. Longer dwell produces improved part forming at no additional cost. This study focuses on knuckle presses architectures to test the proposed method on a variety of systems and to produce the most feasible design. Numerical algebraic methods are particularly relevant here due to their capacity to accurately describe mechanical press architectures while allowing solutions via current numerical methods that guarantee the determination of all solutions to a set of algebraic equations. As such, there are a significant number of companies designing and building mechanical presses to meet a variety of end-user needs. A particularly common need is dwell, the capacity of the press to hold the position on one of its parts while the rest of the machine stays in motion. Dimensioning a new architecture for a mechanical press that produces significantly improved dwell allows for manufacturing parts at a higher rate with lower operating costs.

Dimensioning Mechanical Presses Driven by a Geared Five-Bar for Desired Dwell using Advanced Algebraic Techniques

Xingyu Zhu

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A mechanical press uses a linkage that oscillates a ram in order to form or cut sheet metal. This research develops design theories that use a unique mechanical linkage to obtain alternative ram oscillation patterns, such as a prolonged dwell. A geared five-bar press with sliding output is proposed to produce these alternative motions. In one alternative motion, an extended dwell involves a ram that remains near the bottom of the stroke while the crank continues to rotate. A prolonged dwell is ideal for coining operations. Non-linear loop closure equations are generated using isotropic coordinates. After specifying a desired motion pattern, an algorithm that uses the closure equations with numerical algebraic geometry obtains all possible sets of appropriate dimensions for the links. Lastly, a process to determine the best possible set is formulated.