The Intelligent Servosystems Laboratory

P. S. KrishnaprasadDepartment of Electrical and Computer Engineering

Institute for Systems Research (ISR)

University of Maryland, College Park

July 25, 2003

INSTITUTE FOR SYSTEMS RESEARCH

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, de-Comarmond, ...

Hybrid motor (NSF, ARO), Venkataraman,Loncaric, Dayawansa,Krishnaprasad

Parallel manipulator (NASA, NSF, DOE)Tsai, Tahmasebi, Stamper,...

Snakeboard

Video here

Roller Racer MoviesSean -straight line motion

Sameer - circular arcsand figure eight

Paramecium

Joseph-Louis Lagrange Jean Le Rond d’Alembert Emmy Amalie Noether (1736-1813) (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 ISRFocus 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 ISRFocus 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

Smart System

Neuroscience

Materials

Intelligent Control

Modeling & Optimization

Wireless

Noise &Sensors

Smart PowerMEMS

Signal Processing

Robotics

LINKAGES

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 satellitesTwenty-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

EquationsDistance from receiver to satellite given by:

Pik = i

k + c [dti - dtk] + Tik + Ii

k + dik + ei

k

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

Linearized form of Equation (Using Taylor series)

Pi = -(Uik) ri + Cdti + i

k

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

-Sini*Cosi Sini -Cosi*Cosi

ni = -Sini*Sini ei = Cosi uI = -Cosi*Sini

-Cosi 0 -Sini