This document discusses compliant mechanisms. It defines compliant mechanisms as flexible mechanisms that transfer force or motion through elastic body deformation without joints or linkages. The document outlines the advantages of compliant mechanisms over rigid body mechanisms and describes common design techniques like pseudo-rigid body modeling and topology optimization. It provides examples of compliant mechanism applications and concludes with references on the topic.
2. Compliant Mechanism
Transmission
Some figures of prototype of Compliant mechanism
Advantages of Compliant Mechanisms
Difference between Kinematic and Compliant
mechanism
Design Techniques
PSUEDO-Rigid Body Model
Beam Deformation Modes
Topology Optimization
Manufacturing Technique
Applications
Pipe Crawling Robot
Reference
3. Compliant mechanisms are flexible mechanisms that transfer
an input force or displacement to another point through
elastic body deformation.
These may be monolithic (single piece) or jointless structures.
In other words, A compliant mechanism is a single-piece
mechanism that transfers motion without any relative motion
between joints or linkages, thus causing no friction or
hysteresis loss.
It is a recent development in the field of MEMS designing and
Robotics.
Units- macro, meso, micro, nano..
4. Amplify force or motion
Change direction
Change the dynamics
Change state
8. No joints: No joint friction, backlash or need for lubrication
Easy integration: Can be coupled with modern actuators
(piezoelectric, electromechanical, etc.)
Scalable: equally effective at micro, meso or macro scale
Materials-friendly: Wide range of applicable materials
including steel, aluminum, titanium, polymers, GFRP (Glass
fibre reinforced polymer), CFRP (Carbon Fibre Reinforced
polymer), and metal-matrix composites, shape memory
alloys.
Smaller and lighter: no need to accomodate springs,
fasteners or hinges
Fatigue resistant: stresses are distributed through the whole
device.
9. Kinematic
Ideally…
Zero stiffness along or
about the intended axis.
Infinite stiffness along or
about all other five axes.
Almost no cross-axis errors.
Friction and backlash cause
deviation from the ideal
condition.
Elastic
Ideally and realistically…
Finite but low stiffness
along or about the
intended axis.
Finitely large stiffness
along or about all other five
axes.
Finite cross-axis errors
Friction and backlash are
absent.
Viscoelastic behaviour may
cause deviations.
Axis may drift.
10. Compliant mechanisms are usually designed
using two techniques:
Pseudo-rigid body model
Topology optimization
11. A pseudo rigid-body (PRM) model of a compliant
mechanism can be analyzed using
– Kinematic update equations
– Static equilibrium
The Pseudo-Rigid-Body Method is so called
because it accurately simulates elastic beams
using rigid links and torsion springs which obey
Hooke’s law.
It therefore enables the simulation of
complicated non-linear elastic behaviours using
well-established and comparatively simple
methods for simulating constrained rigid bodies.
12. PRBM Supported
PRBM Unsupported
a) Twist ,+x
axis
b) Bend ,z axis c) bend, y axis
d) Squash , x axis e) Stretch, x axis
f) Shear , z axis
13. Topology Optimization typically involves considering
quantities such as weight, stresses, stiffness, displacements,
buckling loads and resonant frequencies, with the objective
function and others constraints.
Topology optimization can be regarded as an extension of
methods for size optimization and shape optimization.
Size optimization considers a structure which can be
decomposed into a finite number of members.
Shape optimization is an extension of size optimization in
that it allows extra freedoms in the configuration of the
structure such as the location of connections between
members. The designs allowed are restricted to a fixed
topology and thus can be written using a limited number of
optimization variables.
14. (1) Rapid prototyping is a group of techniques used to quickly
fabricate a scale model of a physical part or assembly using
three-dimensional computer aided design (CAD) data.
Construction of the part or assembly is usually done using 3D
printing or "additive layer manufacturing" technology.
(a) 3D printing, also known as additive manufacturing (AM),
refers to processes used to create a three-dimensional
object in which layers of material are formed under computer
control to create an object. Objects can be of almost any
shape or geometry and are produced using digital model data
from a 3D model or another electronic data source such as
an Additive Manufacturing File (AMF) file.
15. (2) Injection Moulding-
Injection moulding is a manufacturing process
for producing parts by injecting material into
a mould. Injection moulding can be performed
with a host of materials like metals, glass,
elastomers, confections, thermoplastic and
thermosetting polymers.
16. Pipe Crawling Robot
Polishing Robot
An Active Uprighting Mechanism for Flying
Robots
Compliant leg
Artificial Heart
Compliant Robotic Arm and so on..
17. Compliant external pipe-crawling robot that can inspect
a closely spaced bundle of pipes in hazardous
environments and areas that are inaccessible tohumans.
The robot consists of two radially deployable compliant
ring actuators that are attached to each other along the
longitudinal axis of the pipe by a bidirectional linear
actuator.
The robot imitates the motion of an inchworm.
Circumferential motion to ring actuators is provided by
two shape memory alloy (SMA) wires that are guided by
insulating rollers. Crawling speed is 45 mm/min.
23. "Ananthasuresh". Mecheng.iisc.ernet.in.
Singh And Ananthasuresh: Compact And Compliant External Pipe-Crawling Robot,
IEEE Transactions On Robotics, Vol. 29, No. 1, February 2013
A. Zagler and F. Pfeiffer, “MORTIZ, a pipe crawler for tube junctions,” in Proc. IEEE
Int. Conf. Robot. Autom., Taipei, Taiwan, Sep. 13–14, 2003,pp. 2954–2959.
L. L. Howell, Compliant Mechanisms. New York: Wiley, 2001.
P. Singh and G. K. Ananthasuresh, “An SMA-actuated, compact, compliant ring-
actuator with uniform deformation,” presented at the 15th Nat. Conf. Mach.
Mechanisms, Chennai, India, Dec. 2011.
K. Hirai, M. Hirose, Y. Haikawa, and T. Takenaka. The development of Honda
humanoid robot in Proceedings of the IEEE International Conference on Robotics
and Automation, volume 2, pages 1321–1326,Leuven, Belgium, 1998.
Nicolae Lobontiu, Compliant Mechanisms: Design of Flexure Hinges.: CRC Press,
2003
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http://compliantmechanisms.3me.tudelft.nl/mw/index.php/CoMe2011