ECE 662- Project Presentation

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14 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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ECE 662
-

Project Presentation


Discrete
-
Time
-

Optimal Control
of a Telerobotic System


Alireza

Mohammadi

Department of Electrical and Computer Engineering

University of Alberta

1 April 2010

Telerobotic Systems


Robotic by remote control (Look at following figure from [2]);


Telerobotic systems are used to extend “a person’s sensing
and manipulation capability to a remote location.”[1]


Standard Telerobotic Systems


Slave robot responds to human operator’s
commands who is interacting with the master
device (joystick/manipulator). Slave device
interacts with the remote environment. (Look
at following block diagram from [2].)



Unilateral VS. Bilateral Telerobotic
Systems


In a unilateral telerobotic system we don’t have any
force/velocity feedbacks from the slave side, we just
use visual and audio feedback from the slave side;
unilateral flow of power variables (velocity/force) from
master to slave.


In a bilateral telerobotic system interaction forces with
the remote environment are reflected back to the
human operator.


Advantage: Human operator can use his/her tactile senses
to perform the remote task efficiently like telesurgery;


Disadvantage: Even a small amount of time delay in
communication channel destabilizes our system; slave
starts oscillating or even moving madly!



Design Specifications for a Unilateral
Telerobotic System


Internal/closed loop stability;


Master compliance, i.e. master velocity should
be a desired function of , ;


Free motion tracking, i.e. slave should be able
to follow master motions when there is no
contact with the remote environment, .

h
f
s
m
v
v

h
m
m
f
v


Leung et al. [1] Proposed Method for
CT Control of Telerobotic Systems


Two
-
step design for a unilateral telerobotic
system;


For a unilateral telerobotic system:


An optimal controller to achieve master
compliance;


An optimal controller to achieve free motion
tracking.

Design for Master Compliance




























m
m
m
m
m
m
m
m
m
P
W
P
W
P
W
P
W
W
G
3
2
1
1
1
0
0
0
How to Connect them Using
Analysis and Synthesis Toolbox


systemnames

=

' Pm Wm1 Wm2 Wm3 F '
;

inputvar

=

'[
fh

; dm1 ; tau_m1]'
;

outputvar

=

'[Pm ;
fh
-
Pm ; Wm1 ; Wm2 ;
F]'
;

input_to_Pm

=

'[fh
-
tau_m1]'
;

input_to_Wm1 =

'[
fh
-
Pm]'
;

input_to_Wm2 =

'[tau_m1]'
;

input_to_Wm3 =
'[dm1]'
;

input_to_F

=
'[Pm+Wm3]'
;

sysoutname

=

'
CTMasterOpenLoop
'
;

cleanupsysic

=

'yes'
;

sysic
;



F: Anti
-
aliasing filter used to before
sampler in the SD control of the master
robot

Design for Free Motion Tracking

Design for Free Motion Tracking







































s
s
s
m
s
s
s
m
s
P
W
W
G
W
P
W
G
W
G
0
0
0
0
0
0
0
0
0
4
3
2
1
1
DT control


Analog design and SD implementation:


SIT of designed CT controller;


BT of designed CT controller.


Direct design in discrete domain:


SIT of open
-
loop system:
G
d
=SGH;


Apply techniques we learnt to the DT open loop
system.

Example


Master robot : one link rigid manipulator:




Slave robot: one link manipulator with two flexible
modes (hard to control), shoulder joint of the
Shuttle Remote Manipulator System:



s
s
P
m
1
)
(

Weighting Functions



design technique tries to make the
tf

from
f
h

to
v
m
-
v
s

like:



Choose
ω
n

and
ζ

such that
desired transient
response

is achieved for :

Master Compliance Test Using a
Triangular Pulse

Master Compliance Test Using a
Triangular Pulse

Master Compliance Test Using a
Triangular Pulse

Master Compliance Test Using a
Triangular Pulse

Master Compliance Test Using a
Triangular Pulse

Master Compliance Test Using a
Triangular Pulse (DT
Hinf

Control!!)

Master Compliance Test Using a
Triangular Pulse (DT
Hinf

Control!!)

Free Motion Tracking Test Using a
Triangular Pulse

Free Motion Tracking Test Using a
Triangular Pulse

Free Motion Tracking Test Using a
Triangular Pulse


References


[1] G. M. H. Leung, B. A. Francis and J.
Apkarian
,
"Bilateral controller for teleoperators with time
delay via &
mu
;
-
synthesis,"
Robotics and
Automation, IEEE Transactions on,
vol. 11, pp.
105
-
116, 1995;


[2] P. F.
Hokayem

and M. W. Spong, "Bilateral
teleoperation: An historical survey,"
Automatica
,
vol. 42, pp. 2035
-
2057, DEC. 2006;


[3] G. J. Balas, J. C. Doyle, K. Glover, A. Packard, R.
Smith, “
mu

analysis and synthesis toolbox for use
with MATLAB”.


Any Questions?