control strategy of hardware-in-the-loop simulator epos 2.0 for autonomous docking verification
Post on 22-Jan-2016
24 Views
Preview:
DESCRIPTION
TRANSCRIPT
Melak Zebenay > EPOS- A Robotics-Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30, 2010
Slide 1
Control Strategy of Hardware-in-the-Loop Simulator EPOS 2.0 for Autonomous Docking Verification
M. Zebenay, T. Boge , R. Lampariello , R. Krenn German Aerospace Center (DLR)
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 2Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Content
EPOS- European Proximity Operation Simulator facility
Docking simulation Concept
Control Strategy
1-DOF Docking Modeling
Target Impedance parameter Identification
Results
Conclusion and future work
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 3Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
EPOS 2.0 -European Proximity Operation Simulator
What is EPOS ?
Laboratory simulation of spacecraft proximity operationsReal-time, real size and real motion simulationHardware-in-the-loop simulator
Why EPOS?Calibrated test bed for proximity operations on RVD missions
quantitative performance tests on equipment level Verification and validation on
equipment levelverification and validation on
system level
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 4Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
EPOS 2.0 -European Proximity Operation Simulator
EPOS 2.0 Performance data:
Motion Ranges:
Range: 25 m
Roll/Pitch/Yaw: 360 deg
Commanding frequency: 250 Hz
Natural frequency : 8-10Hz
Max, Payload: up to 200 kgPosition accuracy (3D/3) : 1.56mm
Orientation accuracy (3D/3) : 0.20deg
Coming new feature of EPOS 2.0 :Online measurement system which measures relative position
Commands corrections to the robots
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 5Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Docking simulation Concept
The goal of docking simulation capability:
Satellite simulator shall accept the measured force/torque and simulate the corresponding dynamic response of the two satellites
EPOS 2.0 facility maneuver the docking hardware to follow the output motion data of the satellite simulator
EPOS 2.0 facility shall have the same impedance (or passivity) as the simulated satellites
Advanced robotics control is suggested to fulfill above requirements
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 6Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Docking simulation Concept
Schematic of EPOS facility control architecture :
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 7Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Control Strategies (1/2)
Control challenges and solution strategies:
System time delay problem
What: Robot does not physically respond to a command immediately
Why: Intrinsic for the industrial robots (not a problem for their industrial applications)
Consequence: Unstable simulation process
Solution: Energy-based simulation process control
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 8Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Control Strategies (2/2)
Control challenges and solution strategies:
Impedance mismatching problem
What: Contact impedance of EPOS does not match that of satellite
Why: docking hardware is constrained to the ground via the robot -
the active robot will interacts with the docking process
Consequence: Simulated docking behavior is inaccurate
Solution: Impedance/admittance robot control strategy
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 9Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
1-DOF Docking Modeling (1/3)
Ideal Satellite 1-DOF docking (contact) modeling
1-DOF Modeling of Satellite Docking using Spring-dashpot contact dynamics model of the contact force
)sin()cos()(
))((
))(11
(
)(
21
21
21
2112
22
11
1
tectectx
xkxbmm
mmx
xkxbmm
xxx
xkxbxm
xkxbxm
xkxbF
tt
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 10
1-DOF Docking Modeling (2/3)
Docking conditions using EPOS 2.0
kc
Compliant F/T
sensor Model
m2
k2
b2
x2
Robot 2 Impedance
model
m1
k1
b1
x1
Robot 1 Impedance
model
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 11
1-DOF Docking Modeling (3/3)
m1 m2
k1
b1
kc k2
b2
TargetM2
ServicerM1
k
b
Satellite docking Model
EPOS 2.0 docking Model
Requirements:
The approximated docking simulation shall have the same dynamic behavior like the real satellite docking model. Therefore it is required to have the same :
Final position and velocity after impact
Impact force/torque
Contact duration
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 12
Target Impedance parameter Identification (1/2)
Dynamic equation of the target Impedance model:
21
2211
mm
xmxmv
u
x
x
x
x
mm
tk
mm
b
m
b
mckk
tkbmmm
m
mck
mbtmkmmmm
ck
mm
tk
mm
b
m
b
mckk
x
x
x
x
0
0
0
0
2
2
1
1
)21
2
21
2
2
2(2
)2(
)22
()21
(2
1
2
1000
)2221
()21
(1
1
1)21
1
21
1
1
1(1
)1(
0010
2
2
1
1
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 13
Target Impedance parameter Identification (2/2)
Determining the unknowns k1, b1, k2 ,b2 assuming m1=M1 and m2=M2:
Computing states t=t1 and t=t2 where t1 and t2 is less than the contact duration.
))()(())()(()(
))()(())()(()(
)()(
)()(
21222122211
11121112111
1
2121
1111
1
1
ztxtxktxtxbtxm
ztxtxktxtxbtxm
txtx
txtx
b
k
cc
cc
))()(())()(()(
))()(())()(()(
)()(
)()(
21222122222
11121112122
1
2222
1212
2
2
ztxtxktxtxbtxm
ztxtxktxtxbtxm
txztxd
txztxd
b
k
cc
cc
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 14
Results
Given M1=750kg, M2=1050Kg, k=500000, b=30 v1(0)=0.3, v2(0)=0 kc=30000, bc=0
Assumed:M1=m1, M2=m1
Unknowns: k1, b1 , k2 and b2
Results: k1=8.0571e+005 b1=51.4286 k2=1.1280e+006; b2=72.0
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2-500
-400
-300
-200
-100
0
100
200
300
400
500
Time (s)
For
ce
(N)
Comparing Forces
Sat Force
Target Imp model Force
Servicer Imp model Force
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2-500
0
500Impact Forces Profile for Sat and Impedance model
Time (s)
For
ce
(N)
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2-500
0
500
Time (s)
Tar
Rob
mod
elF
(N
)
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2-500
0
500
Time (s)
Ser
Rob
Mod
el F
(N
)
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 15
Results
Position and velocity comparison between the ideal satellite and chaser satellite impedance model after contact
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
-16
-14
-12
-10
-8
-6
-4
-2
0
x 10-4
Time (s)
Comparing Displacement of Servicer
Dis
plac
emen
t (m
)
Ser Sat Disp
Imp model Disp
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
-0.035
-0.03
-0.025
-0.02
-0.015
-0.01
-0.005
0
Time (s)
Comparing Velocity of Servicer
Vel
ocity
(m
/s)
Ser Sat velocity
Imp model Velocity
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 16
Results
Position and velocity comparison between the ideal satellite and target satellite impedance model after contact
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
0.9984
0.9986
0.9988
0.999
0.9992
0.9994
0.9996
0.9998
1
Time (s)
Comparing Displacement of Target
Dis
plac
emen
t (m
)
Tar Sat Disp
Imp model Disp
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
-0.03
-0.025
-0.02
-0.015
-0.01
-0.005
Time (s)
Comparing Velocity of Target
Vel
ocity
(m
/s)
Target Sat velocity
Imp model Velocity
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 17
Conclusion and future work
Experiment using EPOS 2.0 to investigate the contact duration and contact force using different stiffness material.
Testing the target impedance using EPOS 2.0 is in progress
Extend the target impedance identification method for 3-DOF
Implement the control algorithm using the computed target impedance
Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide 18Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide Melak Zebenay >EPOS-A Robotics- Based Hardware in-the-Loop Simulator for Simulating Satellite RvD Operations >Aug 30,2010
Slide
Thank You!
top related