This paper is focused on the motion control problem for a laparoscopic surgery robot assistant with an actuated wrist. These assistants may apply non-desired efforts to the patient abdomen. Therefore, this article proposes a control methodology based on three feedback levels, which have been defined as layers. These layers control different aspects of the endoscope movement. A low level assures the dynamic of the robot assistant is performed accordingly. The mid level emulates a passive wrist behavior to avoid any efforts over the abdomen. An external high level deals with the global movement planning. This architecture also makes easier to analyze the stability of the whole system. Finally, a real in-vitro experiment has been implemented with an industrial robot in order to contrast the validity of this article procedure.

1. International Conference on Robots and Systems 2009
THREE-LAYER CONTROL FOR ACTIVE WRISTS IN
ROBOTIZED LAPAROSCOPIC SURGERY
Enrique Bauzano-Núñez, Víctor Muñoz-Martínez
Isabel García-Morales, Belén Estebanez-Campos
System Engineering and
Automation Department
System Engineering and Automation Department
http://www.isa.uma.es
University of Malaga (Spain)
Enrique Bauzano Nuñez
ebauzano@uma.es

2. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
OUTLINE
I. General Overview
II. Laparoscopic Navigation Problem
III.Control Strategy
IV.Implantation and Experiments
System Engineering and
Automation Department
V. Conclusions and Future Works
Enrique Bauzano Nuñez
ebauzano@uma.es

3. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments
V.Conclusions
I. GENERAL OVERVIEW
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es

4. I. General Overview
CISOBOT: SEMI-AUTONOMOUS ROBOT ASSISTANT
INDEX
I. Overview
II.Laparoscopic Surgeon
Navigation
Tool Movement Voice Command
III.Control
Strategy
IV.Experiments
V.Conclusions
3D Tracking
Navigation
Tool
Position/Orientation
Controller
Surgeon Maneuver
Model Robot
System Engineering and
Automation Department
Direct Intervention
Processed Assistant
Image
Image
Processing
Patient
Enrique Bauzano Nuñez
ebauzano@uma.es

5. I. General Overview
ROBOTIC WRISTS COMPARATIVE
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy •  Null forces on abdomen
IV.Experiments •  Precision depends on fulcrum
V.Conclusions
accuracy
•  Null forces on abdomen
•  Special instruments needed
•  Previous calibration
System Engineering and
Automation Department
•  Voluminous mechanisms
•  No additional mechanisms on wrist
•  No special instruments needed
•  Low volume
•  May apply forces on abdomen
Enrique Bauzano Nuñez
ebauzano@uma.es

6. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments
V.Conclusions
II. LAPAROSCOPIC NAVIGATION PROBLEM
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es

7. II. Laparoscopic Navigation Problem
GLOBE-SHAPED MOVEMENTS
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments {I} Fulcrum point
V.Conclusions
 Orientation angle
 Altitude angle
 External distance
System Engineering and
Automation Department
Aim: “Solve the motion problem of an endoscope for a laparoscopic
surgery robot assistant with an actuated wrist.”
Enrique Bauzano Nuñez
ebauzano@uma.es

8. II. Laparoscopic Navigation Problem
NAVIGATION STRATEGY
INDEX
I. Overview
ZI
II.Laparoscopic
Navigation
L3
III.Control
L1
Strategy
1. Rotate around estimated fulcrum
IV.Experiments
Fulcrum displacement over the abdomen
V.Conclusions
2. Passive Wrist Behavior
Endoscope rotation over the wrist to reduce C
fulcrum displacement
System Engineering and
Automation Department
3. Altitude angle correction
Recover desired altitude angle
XI I
Enrique Bauzano Nuñez
ebauzano@uma.es

9. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments
V.Conclusions
III. CONTROL STRATEGY
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es

10. III. Control Strategy
SYSTEM ARCHITECTURE
INDEX
I. Overview
Layer-1 Voice Command
II.Laparoscopic
Spherical Control Surgeon
Navigation
III.Control
Strategy Spherical Reference
IV.Experiments
Layer-2
Passive Wrist Emulation
V.Conclusions
Spherical
Cartesian Reference
Location
Layer-3
Cartesian Control
Joints
Location
System Engineering and
Joint
Automation Department
Reference
Fulcrum
Robot Arm
Estimation
Arm
displacement
Endoscope-Abdomen Force
Interaction
Patient
Enrique Bauzano Nuñez
ebauzano@uma.es

11. III. Control Strategy
SPHERICAL CONTROL LOOP (LAYER-1)
INDEX
I. Overview
II.Laparoscopic
Navigation d e
Fd
III.Control Robot
T1  (kT1 )
+
Strategy Trajectory
e
Lr PWE
Generator
IV.Experiments  d (kT1 ) r Controller
+-
V.Conclusions T1
c
Control PI
Layer-1
Spherical Control PI
System Engineering and
Automation Department
Action: Recover desired trajectory, which has been changed
with the passive wrist emulation (Layer-2).
1 1  e T1 / 
Control PI Law: K I1 
1  e T1 / 
; K P1 
(1  e T1 /  )  e
Enrique Bauzano Nuñez
ebauzano@uma.es

12. III. Control Strategy
PASSIVE EMULATION BEHAVIOR LOOP (LAYER-2)
Endoscope-Abdomen Interaction
INDEX F (kT2 ) Gravity
I. Overview M (kT2 ) Sensor
External Distance
+ T2 
II.Laparoscopic Estimator -
Navigation
III.Control e (kT2 )  (kT2 )
Strategy
Control PI
IV.Experiments Layer-2
V.Conclusions r
-
+
Fc (kT2 )
Lr
Robot T2  (kT2 )
+
Cartesian
Fd - Fr (kT2 ) 1 r (kT2 ) +  r (kT2 ) Controller
-
+ ee
System Engineering and
Automation Department
Control PI Forces
Action: Reduce abdominal forces through a passive wrist
emulation movement.
Fx2  F y2 M
e 
Passive Angle: 
 e Fx2  Fy2
1 e (1  e T /  )
2
KI2  ; K P2 
Control PI Law: 1  e T2 /  (1  e T2 /  )
Enrique Bauzano Nuñez
ebauzano@uma.es

13. III. Control Strategy
CARTESIAN CONTROL LOOP (LAYER-3)
INDEX
e
I. Overview
r 
X r (kT3 )
II.Laparoscopic Cartesian
Navigation Planner
III.Control T3 X r (kT3 )  T3
Lr  r (kT3 )
Strategy + KX ++ 1
J ( ) Robot T3
- z 1
IV.Experiments
V.Conclusions
X (kT3 )  (kT3 )
F ( )
 (kT3 )
Cartesian-Spherical
Transform
System Engineering and
Automation Department
Action: Adapt robot dynamics to a first order behavior.
Control Law:  r  J 1 ( )(K x X  X r )
 
Enrique Bauzano Nuñez
ebauzano@uma.es

14. III. Control Strategy
STABILITY
INDEX
I. Overview
II.Laparoscopic Spherical Level (Layer-1) and Passive Wrist Emulation (Layer-2):
Navigation
Eigenvalues on dynamic matrices must be lower than one.
III.Control
Strategy
IV.Experiments  1 e    1  1 e  1 1
A1   A2    (   e )  1 ;  e ( e   )  1
1 1 
;
V.Conclusions  1       e
Stability condition:
System Engineering and
Automation Department
 e  2  ;  e  0.5
Enrique Bauzano Nuñez
ebauzano@uma.es

15. III. Control Strategy
STABILITY
INDEX
I. Overview
II.Laparoscopic Cartesian Level (Layer-3): Null dynamic error for proposed trajectory.
Navigation
III.Control
Strategy  
 r  J 1 ( )( K x X  X r )
IV.Experiments
V.Conclusions
Cartesian planner
PID
System Engineering and
Automation Department
K x X  X r  J 1  
 
T T
 kT3  T3   kT3 
 d

Kx X  X r  0
Enrique Bauzano Nuñez
ebauzano@uma.es

16. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments
V.Conclusions
IV. IMPLANTATION AND EXPERIMENTS
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es

17. IV. Implantation and Experiments
EXPERIMENT 1: IN-VITRO TRIAL
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy 2
IV.Experiments
V.Conclusions
forces (N)
System Engineering and
Automation Department
-2
0 time (sec) 30
Enrique Bauzano Nuñez
ebauzano@uma.es

18. IV. Implantation and Experiments
EXPERIMENT 2: ALTITUDE ORIENTATION
INDEX
I. Overview
II.Laparoscopic
Navigation
Orientation Angle
III.Control
Strategy
IV.Experiments
V.Conclusions
Altitude Angle
System Engineering and
Automation Department
Force on Fulcrum
Enrique Bauzano Nuñez
ebauzano@uma.es

19. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
INDEX
I. Overview
II.Laparoscopic
Navigation
III.Control
Strategy
IV.Experiments
V.Conclusions
V. CONCLUSIONS AND FUTURE WORKS
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es

20. V. Conclusions
CONCLUSIONS
INDEX
The methodology proposed simplifies the
I. Overview
II.Laparoscopic
controller design by dividing the problem in
Navigation
simpler subtasks.
III.Control
Strategy
IV.Experiments
System behavior may be easily studied:
V.Conclusions stability, transient response, or steady state.
Useful scheme for fault tolerance analysis.
FUTURE WORKS
System Engineering and
Automation Department
Extend the controller features to read interaction forces inside the
abdominal cavity in order to perform tasks like displace tissues, cutting
operations, stitch…
Planning automatic movements according to surgeon commands.
Use flexible tools instead a rigid endoscope.
Enrique Bauzano Nuñez
ebauzano@uma.es

21. 3-Layer Control for Active Wrists in Robotized Laparoscopic Surgery
Thanks for your attention
System Engineering and
Automation Department
Enrique Bauzano Nuñez
ebauzano@uma.es