Upload
tatiana-pace
View
31
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Design of Low-Power Silicon Articulated Microrobots. Richard Yeh & Kristofer S. J. Pister. Presented by: Shrenik Diwanji. Abstract - PowerPoint PPT Presentation
Citation preview
Design of Low-Power Silicon Articulated Microrobots
Richard Yeh & Kristofer S. J. Pister
Presented by:
Shrenik Diwanji
Abstract
To design and build a class of autonomous, low power silicon articulated micro-robots fabricated on a 1 cm2 silicon die and mounted with actuators, a controller and a solar array.
Designing
Primarily based on micro-machining Pros
Feature sizes in sub micronMass production
ConsDesigning from scratch
Basic model of the micro-robot.
Actuator Design
Main backbone of the robot designShould have high W/kg3 ratioDifferent types of actuators:-
Piezoelectric Thermal and shape-memory alloy Electromagnetic Electrostatic
Piezoelectric actuators
Pros Produce large force Require low power
Cons Require high voltage ~ 100v. difficult to integrate with CMOS electronics
Thermal and Shape-memory alloy actuators
Pros Robust Easy to operate
Cons High current dissipation ( 10s of mA)
Electromagnetic actuators
Pros High Energy Density
Cons Needs external magnet and / or high
currents to generate high magnetic fields
Electrostatic actuators
Pros Low power dissipation. Can be designed to dissipate no power
while exerting a force. High power density at micro scale. Easy to fabricate.
Electrostatic actuator design
Gap Contraction Actuator
_ 1Et l v2
2 d2Fe =
Scaling EffectsActuator force
Frequency
Dissipative forceGravitational force
Squeeze-film damping
Resistance of spring support
Power density
Inch Worm Motors.
Design of Inch Worm Motors
Inch Worm Cycle
Prototype design and working
Power requirements
Main areas of power dissipation CMOS controller Actuators
Power dissipation in actuators Weight - 0.5mN Adhesion force - 100µN
C = Total capacitanceF = frequency
Designing Articulated Rigid Links
Shape of the links Flat links
Cons Less strength due to 2 thin poly crystalline layers
HTB Pros
Good weight bearing capacity
Mounting of the solar array and the chip
Designing Articulated Rigid Links
Mechanical Coupling of the legs
Power Source Solar array is used η = 10 % ( max 26%) Power density = 10mW/cm2 (100 mw/cm2, η = 26%)
Controller
Open loop control (as no sensors)CMOS controller
Simple finite state machine Clock generator Charge pump
Logic behind walking of the Robot
Gait speed
Gait speed = Δx/T In one leg cycle
Δx = 100μm
T = 15 ms.
With GCA to leg displacement factor of 1:10 GCA gap – stop size of 2μm. Operating frequency of 1kHz.
Gait Speed = 100/15 = 7mm/s
Robot assembly
Difficulty The size of the robot The strength needed for perfect
mechanical couplingSolution
Flip chip bonding Allows the micro machined devices to be
transferred from substrate to another.
Conclusion
Key design issues Actuation power density Actuators used
Key tools Micro machining