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Research
Compliant Mechanism Synthesis for Adaptive Shape Change Applications (Kerr-Jia Lu)
Compliant Building Block Synthesis (Charles Kim)
Disk Drive Microactuation (Charles Kim)
Embedded Actuation and Biomimetic Compliant Systems (Brian Trease)
Compliant Joints (Brian Trease)
Utilizing Compliance in Human Assistance Applications (Michael Cherry)
Biologically Inspired Compliant Mechanisms (Christine Vehar)
Tape Springs as Elements of Fully Compliant Mechanisms (Christine Vehar)
Design of Compliant Mechanisms for Dynamic Performance (Tanakorn Tantanawat)
Application of Compliant Mechanisms to Active Vibration Isolation Systems (Tanakorn Tantanawat)
Projects
Motorcycle Suspension System with Large-Displacement Compliant-Joints (Cavin Daniel)
Five-Bar Haptic Control Device (Audrey Plinta and Brian Trease)
Navy Fins (Brian Trease)
Minimally Invasive Vascular Clamp (Michael Cherry and Tanakorn Tantanawat)
Compliant Hemostat (Christine Vehar and Zachary Kreiner)
Kidney Gripper (Zachary Kreiner)
Compliant Mechanical Pencil (Kerr-Jia Lu, Charles Kim, Christine Vehar, Audrey Plinta, and Tanakorn Tantanawat)
Statically Balanced Compliant Mechanisms (Brian Trease)
Robo-Fish (Dragan Maric)
Compliant Mechanism Synthesis for Adaptive Shape Change Applications
Kerr-Jia Lu
Compliant Building Block Synthesis
Charles Kim
The synthesis of fully compliant mechanisms is typically performed
either by optimization or intuition. Research in synthesis by
optimization has yielded satisfactory results that are usually eclipsed
by designs produced by intuition. In this work, a conceptual approach
is taken for the design of compliant mechanisms. To this end, a
building block methodology is implemented at the conceptual stage of
compliant mechanism design, while a size and geometry optimization is
implemented to refine the design to satisfy performance criteria. To
implement a building block synthesis, it is necessary to both identify
and characterize specific building blocks. A library of building blocks
is to be identified along with tools to quantify a building block’s
kinematic and energy characteristics. Additionally, a method for task
decomposition is being investigated for the building block methodology.
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Slide Shows:
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Related Papers
An Instant Center Approach to the Conceptual Design of Compliant Mechanisms
Disk Drive Microactuation
Charles Kim
One of the bottlenecks limiting data density in conventional disk
drives is the resonant frequency of the suspension arm connecting the
actuator and the read-write elements. In this work a compliant
transmission is integrated with a secondary electrostatic microactuator
to address this limitation. The compliant transmission was designed to
reduce overall footprint.
The device was refined using size and geometry optimization with
respect to energy efficiency. A tight constraint was imposed on the
natural frequency of the entire device to facilitate sufficient
bandwidth. The device was fabricated by the MEMX Corporation.
Slide Shows:
[Powerpoint File]
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Related Papers
Design of a Novel Compliant Transmission for Secondary Microactuators in Disk Drives
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Embedded Actuation and Biomimetic Compliant Systems
Brian Trease
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While all compliant mechanisms are “biologically-inspired” in their dependence on
elastic deformation, I am working to take biomimetic design several steps
further, beyond singly-actuated, planar isolated mechanisms. The goal is to
include actuators, sensors, structures, and other material needs all in one
optimization problem. Thus, the research effort is to move from compliant
mechanisms to compliant systems.
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There is also the task of mimicking specific biological systems.
Kerr-Jia and I are currently working to join our technology with new artificial
muscles from the Navy to develop a compliant hydrofoil. This actuated fin will
be capable of producing aquatic propulsion in the same manner as a fish,
including the complex 3-D deformation of fins in stroke motion. The task is
accomplished in part by arranging 2-D compliant building blocks in a spatial
configuration.
Slide Shows:
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Synthesis of Adaptive and Controllable Compliant Systems with Embedded Actuators and Sensors
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Compliant Joints
Brian Trease
Slide Shows:
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Utilizing Compliance in Human Assistance Applications
Michael Cherry
The purpose of this research is to increase performance of healthy individuals and restore mobility
to people with disabilities. The two major thrusts are: (1) Upper body: develop a flexible backpack
suspension, allowing user to carry additional load while decreasing metabolic cost and user fatigue
and (2) Lower body: design a spring-like exoskeleton, increasing stride length for faster running and
provide strain-energy storage/transfer for jumping. The research is founded on fundamentals of design
and analysis of passive dynamic compliant systems and modeling human motion.
Slide Shows:
[Powerpoint File]
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Biologically Inspired Compliant Mechanisms
Christine Vehar
I propose that medical applications, such as the cleverly intrinsic, multi-part prosthetic devices and
artificial organs, can be astronomically improved if redesigned as biologically inspired compliant mechanisms.
I wish to unlock nature’s design “rules of thumb” and put it in a language that can be understood by both design
engineers and optimization software. I feel that my approach to compliant mechanism creation is innovative and
more comprehensive than other approaches since it is based on flexible mechanisms that work, and have been
working for millenniums.
Slide Shows:
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Tape Springs as Elements of Fully Compliant Mechanisms
Christine Vehar
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Tape spring fold acting as a revolute joint
with a large range of motion |
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A 3-fold closed-loop tape spring |
This research introduces tape springs as elements of fully compliant mechanisms. The localized folds
of tape springs serve as compact revolute joints, with a very small radius and large range of motion,
and the unfolded straight segments serve as links. By exploiting a tape spring’s ability to function
as both links and joints, we present a new method of realizing fully compliant mechanisms with further
simplification in their construction. Tape springs, typically found in carpenter tape rules, are thin-walled
strips having constant thickness, zero longitudinal curvature, and a constant transverse curvature.
This research presents a closed-loop tape spring mechanism. By representing its folds as idealized
revolute joints and its variable length links as sliding joints connecting rigid links, we present a
modified Gruebler’s equation to determine its kinematic and idle degrees of freedom. To realize practical
utility of tape spring mechanisms, we demonstrate a simple actuation scheme incorporating shape memory
alloy (SMA) wire actuators in a physical tape spring model.
Slide Shows:
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Related Papers
Closed-Loop Tape Springs as Fully Compliant Mechanisms - Preliminary Investigations
Design of Compliant Mechanisms for Dynamic Performance
Tanakorn Tantanawat
When analyzing or designing compliant mechanisms, early researchers usually assumed a
quasi-static condition. Consequently, the analysis and design tools developed based on
this assumption are limited to quasi-static applications. In addition, some benefits of
compliant mechanisms in dynamic applications may be hidden by a quasi-static assumption.
In this research, energy storage capability of compliant mechanisms, which has not been
fully exploited at least in a systematic manner in any previous research, will be exploited
to reduce energy consumption of a system under dynamic loads. A design method directly
addressing energy consumption is proposed as a proof of concept. Design of a flapping mechanism
for a mechanical flying insect will be used as a case study to illustrate the proposed design
method.
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| In conventional mechanisms, kinetic energy in a flywheel can be used to reduce input power requirement |
Similarly, strain energy in a compliant mechanism can be used to reduce input power requirement. |
Slide Shows:
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Design of Compliant Mechanisms for Minimizing Input Power in Dynamic Applications
Application of Compliant Mechanisms to Active Vibration Isolation Systems
Tanakorn Tantanawat
In this research, we explore an application of compliant mechanisms for active vibration isolation
systems. An actuator and a compliant mechanism are used to cancel undesired disturbance, resulting
in attenuated output amplitude. An actuator provides external energy to the system while a compliant
mechanism functions as a transmission controlling the amount of displacement transmitted from the
actuator to the payload to be isolated.
Slide Shows:
[Powerpoint File]
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Related Papers
Application of Compliant Mechanisms to Active Vibration Isolation Systems
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Motorcycle Suspension System with Large-Displacement Compliant-Joints
Cavin Daniel
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The relatively high number of parts present in traditional suspension
systems can often adversely affect the total cost and weight of the
system. Minimizing suspension weight and complexity through use of
compliant revolute joints has many benefits in manufacturing and
system performance. Minimizing complexity reduces the assembly costs
of creating the suspension and minimizing sprung weight will enable
a suspension to perform better (i.e. more responsive). The compliant-joint
suspension omits many of the bearings, bushings, and coil spring(s) of a
conventional system and replaces the joints with stiffness supplying
compliant joints.
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| Conventional System |
Compliant Revolute Joint |
Compliant System |
Slide Shows:
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Five-Bar Haptic Control Device
Audrey Plinta and Brian Trease
Compliant revolute joints were integrated into a five-bar haptic device with two degrees of freedom.
This haptic device was used for testing by undergraduate students. The mechanism provides a
force-feedback interface with the student at a single point in the working plane. Any two-dimensional
virtual environment can be created, complete with interactive virtual springs, sprung masses, walls,
gratings, viscous fluids, negative stiffness, and more.
The initial motive for integrating the compliant revolute joints into this mechanism was to reduce
the manufacturing cost by eliminating the bearings originally used at the joints. Another benefit
gained is the friction from the conventional joints has now been replaced with torsional spring forces.
Spring forces are much easier to model than friction (non-conservative, nonlinear), and thus make it
much easier to implement a controller.
Slide Shows:
[Powerpoint File]
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Navy Fins
Brian Trease
Slide Shows:
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Minimally Invasive Vascular Clamp
Michael Cherry and Tanakorn Tantanawat
A blood vessel clamp is a device commonly used during an organ transplant to stop flow
in a blood vessel. However, with the current blood vessel clamp design, many doctors found
that the clamp often damages the vessels (more than 50% of cases). After investigating the
current clamp design, we were able to identify two issues. In this project, a compliant vascular
clamp was designed to solve the problems through the use of material compliance.
Slide Shows:
[Powerpoint File]
[HTML File]
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Compliant Hemostat
Christine Vehar and Zachary Kreiner
Slide Shows:
[Powerpoint File]
[HTML File]
Kidney Gripper
Zachary Kreiner
Slide Shows:
[Powerpoint File]
[HTML File]
Compliant Mechanical Pencil
Kerr-Jia Lu, Charles Kim, Christine Vehar, Audrey Plinta, and Tanakorn Tantanawat
Five parts of the conventional mechanical pencil consolidated in to one part
A new, compliant mechanical pencil offers novel features through the consolidation of multiple parts
into one. The current design of a mechanical pencil consists of various small parts. The function of
the pencil’s mechanism is to feed an object by using a reciprocal input motion to produce a unidirectional
output motion on the object. The compliant mechanical pencil utilizes flexural elements to provide
various functions usually performed by the members of conventional mechanical pencils. The mechanism
is scalable and a building block for compliant feeding mechanisms. Further benefits include ease of
assembly and reduced manufacturing capital costs.
Slide Shows:
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Statically Balanced Compliant Mechanisms
Brian Trease
Slide Shows:
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Robo-Fish
Dragan Maric
[Download Robo-Fish Video]
Slide Shows:
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One of the many superior features of compliant mechanisms is the distributed deformation field,
which is particularly attractive when dealing with adaptive systems, such as shape change in
aircraft wings and antenna reflectors. In order to achieve a desired shape change, the objective
of this research is to develop a systematic compliant mechanism synthesis approach for a desired shape change.
