Tele-Operation systems summer 2013 @ Tehran

1. Tele-Operation Systems
Presence of “Linear Control Systems”
Lecturer : Mansour.Nch
TeleOperation Conference
Email:PowerSt.Basu@gmail.com
Tel: +98 – 935 658 9590
Summer 2013
R(S) G(S) F(S)
H(S)
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2. Introduction
 indicates operation of a machine at a distance.
 but is most commonly associated with robotics and
mobile robots
 but can be applied to a whole range of
circumstances in which a device or machine is
operated by a person from a distance.
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3. Integrated Model
R(S) G(S) F(S)
H(S)
Tele-Operation
System
Human
Operator
Environment
Xh -Xe
Fh Fe
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4. Diagramof the bilateralTeleoperation
Master
System
Slave
System
Communication
System
Vm Vmd
fsfsd
I. the human operator commands via a master manipulator by exerting a force fh
II. The master moves with velocity: Vm
III. the slave manipulator responds to the reference signal: Vmd
IV. the force fs sensed as a result of contact with the environment and/or some
external source.
V. fe , is transmitted back to the master network, which results in the force fsd to
the master.
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5. Infrastructures needed
Communication Infrastructure
Control Infrastructure
Network Infrastructure
Security Infrastructure
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6. Communication Infrastructure
• This Scenario needs a high availability Connection to respond
more faster! , so maybe H-system can solve this Problem
H-System
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7. Master Device Slave Device
A link with high availability Connection
Usually uses Fiber-Optic Technology
When Master fails , Slave Portion Detect this fault immediately
and achieve the control mechanism so fast!
This is a High Redundant Scenario
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8. Control Infrastructure
Human
Operator
Hand
Controller
Local Delay
Compensation
Environment
Remote Delay
Compensation
Mobile
robot
H1
H2
Delay
Delay
Remote SiteLocal Site
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9. A big challenge: Time Delay
When local station sends electronic bits to remote station, some delay will be appeared in system
output. several methods are presented since 1957 considering time delay.
1. in 1957, Time delay problem in process control was first tackled by Smith
2. 1981, Vertut showed that the stability of teleoperation systems with delay time could be achieved
by decreasing bandwidth of the system
3. In 1997, Niemeyer and Slotine used wave variables method in teleoperation systems using
passivity theory
4. In 1999, Maza and Velasco-Villa predicted the state of linear systems with time-delays in the input
and the state
5. Park and Cho applied sliding mode methods for controller design in teleoperation systems with
delay time in 1999
6. Prediction, generally in the form of smith predictors (smith 1957), can be combined with wave-
based systems to reduce the effects of the delay (Ganjefar, Momeni & Janabi-sharifi 2002)
7. In 2003 Azorin used A new control method of teleoperations with time delay
8. In 2006 Sirouspour used a LQG controller in teleoperation systems with constant time delay
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11. General Bilateral Teleoperation
• Bilateral: When the contact force is reflected via the master
• actuator to the operator’s hand, the teleoperator system
• is said to be bilateral or force reflecting.
• A bilateral teleoperation Components
Human Master Controller Slave Environment
Vh Vm Vmd Ve
fh fsd fs fe
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12. Scenario of Time Delay in WAN
• The challenge of delivering a packet to the remote station
contains the following factors:
• 1. TTL
• 2. bandwidth
• 3. WAN Speed
• 4. security parameters
• 5. signal processing (Noise , etc.)
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13. Wave variables method
• presents a modification or extension to the theory of passivity
• This method is also closely related to the scattering and small
gain theories.
b
√(2b)
√(2b)
X
F
U
V
F is force
X is velocity
U is forward
V is backward
The basic wave transformation
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14. SMITH Predictor Method
• For systems with a pure transport lag
• allowed for a high loop gain in order to provide better accuracy
• C(s) is a proportional controller (i.e. C(s)=k)
• P(s) is a first order filter with transport lag
•
•C(s)=k ;
C(S) P(S)
r e u y
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( )
1
Ts
e
P S
Ts

15. 4/23/2014
( )
( ) 1
Ts
Ts
y s Ke
r s Ts Ke
( )S
A Delay Term has been appeared in
characteristic equation
So, What the scenario?
In order to remedy this problem
SMITH proposed a minor correction loop around the controller
C(S)
e u•
P(S)(1-e^TS) Compensation
loop

16. C(S) P(S)
r e u y•
P(S)(1-e^TS)
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C(S) P(S)
r e u y

17. 4/23/2014
C(S) P(S)
r e u y•
P(S)(1-e^TS)
The closed-loop system is stable
for any ∆T if:
and for a finite ∆T , if :

18. Network Infrastructure
• Commonly Operating in a Isolated Network
• Using Cisco Technologies
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19. Conclusion
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Velocity in master and slave (rad/s)

20. 4/23/2014
Position in master and slave (rad)

21. 4/23/2014
Force in Master/slave (N.m)

22. 4/23/2014
Position error in master and slave (rad.)

23. 4/23/2014
Velocity error in master and slave (rad./s)

24. References
IEEE Journals:
[1] G. Niemeyer and J.-J. E. Slotine. “Using Wave
Variables for system Analysis and Robot Control”.
Proc. 1997 IEEE. Int. Conf. Robotics and
Automation, Albuquerque, New Mexico, pp 1619-
1625.
[2] J. H. Park and H. Cho, “Sliding–Mode Controller
for Bilateral Teleoperation with Varing Time Delay
[3] Elhajj and N. Xi, “Real–Time Control of Internet
Based Teleoperation with Force Reflection”, Proc.
2000 IEEE Int. Conf. Robotics and Automation,
San Francisco CA, April 2000.
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