INSTITUTE FOR SYSTEMS RESEARCH
The Intelligent Servosystems Laboratory
P. S. Krishnaprasad
Department of Electrical and Computer Engineering
Institute for Systems Research (ISR)
University of Maryland, College Park
July 25, 2003
BRIEF HISTORY
• 1986: Began as a small lab devoted to the
study of
– Control of flexible-link robotic arms
(Westinghouse)
– Tactile sensory processing for Si membrane
sensor (NRL)
– 3-D graphics and related algorithms (NASA,
AFOSR)
BRIEF HISTORY (cont’d)
• Evolution in A.V. Williams Bldg. as a lab
devoted to the study of
– actuators
– manipulators
– complex multi-body systems
via physical experiments and
simulations.
BRIEF HISTORY (cont’d)
• Highlights include experiments in
– friction modeling and adaptive control
(Westinghouse)
– impact control (ARO)
– design, fabrication and grasp analysis (NSF)
– testbed for space robotics (NASA)
– smart motor network (NSF)
– walking robots (NASA, NSF)
Modular dextrous
hand,
(NSF, AFOSR)
Loncaric, deComarmond, ...
Hybrid motor (NSF,
ARO), Venkataraman,
Loncaric, Dayawansa,
Krishnaprasad
Parallel manipulator
(NASA, NSF, DOE)
Tsai, Tahmasebi,
Stamper,...
Snakeboard
Video here
Roller Racer Movies
Sean -straight line
motion
Sameer - circular arcs
and figure eight
Paramecium
Joseph-Louis Lagrange
(1736-1813)
Jean Le Rond d’Alembert Emmy Amalie Noether
(1717-1783)
(1882-1935)
GOALS OF LAB
• To advance the state-of-the-art in design and
real-time control of smart systems, drawing
on advances in
– Novel sensing and actuation materials and
mechanism designs
– New principles for actuation, propulsion,
detection, reduction, learning and adaptation
– Conceptualizing and prototyping across scales,
to sense, actuate, communicate and control
RESEARCH & EDUCATION
The lab as a facility for education and training
– Education and training of some 30 M.S.
students and 34 Ph.D. students since 1986, all
of whom had participated in some significant
way in the lab through experimental and
computational investigations in addition to
engaging in theoretical investigations.
RESEARCH & EDUCATION
The lab as a facility for education and training
– Involvement of undergraduates and high school
students in the lab through REU programs and
Young Scholar programs, continually, over the
past 14 years.
ROLE IN ISR
Focus on
• research in problems of interaction of
physical systems with software systems
– mobile robots with on-the-fly motion planning
algorithms
• integrated approach to the design and
control of smart systems
– biologically inspired approaches to sensory
processing and motion control
ROLE IN ISR
Focus on
• research in the science of controllable
materials
– hysteresis from first principles
– nonlinearity in adaptive optics
• A facility for research in real time control
prototyping
– dSPACE
LINKAGES
Wireless
Neuroscience
Robotics
Intelligent Control
Smart System
Noise &
Sensors
Signal Processing
Smart Power
MEMS
Modeling & Optimization
Materials
CURRENT PROJECTS
• Robotics (serial, parallel, mobile, small, …)
– GPS-enhanced robotics
• Smart materials, devices and systems
(CDCSS)
– Hysteresis
– Actuator arrays for adaptive optics (CDCSS
and ARL)
CURRENT PROJECTS
• Smart manufacturing (NG, NSF)
– Understand Si epitaxy, Si-Ge epitaxy via CFD
– Process Control
• Links with biology (LIS, CAAR, NACS)
– Learning and intelligence
– Robotic barn-owl
ROBOTIC BARN OWL
GPS CAR
GPS CAR
GPS CAR AND ANTENNA
MENTORING
GPS CONFIGURATION
GPS is a satellite navigation system using NAVSTAR
satellites
Twenty-four operational satellites provide GPS
receivers with satellite coverage at all times
GPS Orbit Configuration
GPS-aided Location Determination and Navigation
Receiver requires minimum of four satellites
GPS in Differential mode
Equations
Distance from receiver to satellite given by:
Linearized form of Equation (Using Taylor series)
Pik = ik + c [dti - dtk] + Tik + Iik + dik + eik
Pi = -(Uik) ri + Cdti + ik
Pik = pseudorange
ik = ||ri – rk|| = distance between satellite and
receiver
= {(Xi – Xk)2 + (Yi – Yk)2 + (Zi – Zk)2}1/2
ri = position of receiver
rk = position of satellite
c = speed of light
dti = clock bias in receiver
dtk = clock bias in satellite
Tik = Tropospheric correction
Iik = Ionospheric correction
dik = multipath correction
eik = noise
Pi = observed position – calculated position
(Uik) = unit vector from receiver to satellite
ri = actual position – initial estimate
dti = actual receiver clock bias – initial estimate
ik = error terms
Global to Local coordinates transformation
-Sini*Cosi
ni = -Sini*Sini
-Cosi
Sini
-Cosi*Cosi
ei = Cosi uI = -Cosi*Sini
0
-Sini