Transcript TCS3 Servo System - NASA Infrared Telescope Facility

TCS3 Servo System
Proposed Design
Why Model?





Meet Resolution Requirements
What Resolution Encoder to use?
Velocity Configuration
PID Values
Wind Loading Tests
Tests





10 arcsec Offset
15 arcsec/sec Track
Open/Closed Loop Response
Wind Loading
Frequency Sweep
JPL System
Gain10
Continuous
RMS
Step1
Product
206271
CRMS
Gain8
206271
Gain9
Mech
206271
-Kc1
Ramp
a2
Gain7
Manual Switch
Gain
Gain2
1
s
Integrator
s+alpha
s+beta
Transfer Fcn
position
a1
kk1
torque
v elocity
Gain4
Gain5
mechanical_system
m
Step
Gain6
c3
Gain3
c4
Gain1
|u|
Abs
JPL Step
JPL Track
Present System vs. JPL System






Added Transfer Functions
Added Quantization Blocks
Added Rate Limiter
Dual Opposing Motor Mechanical Model
Disturbance Rejection in Velocity loop
Adjust C3 and C4 gains to reflect present
system components
JPL 5 DOF Mechanical Model
Matlab 5 DOF Mechanical Model
IRTF 6 DOF Mechanical Model
Matlab 6 DOF Mechanical Model
Wind Loading Calculations
Wind Loading Calculations
Matlab Model for Wind Disturbances
Mechanical Model Simulation
Present System
produced disturbance (wind) N*m
Subsystem
1
c4
0.162s
DAC
Gain7
0.875
Integrator
470E-6s+1
Integrator
Limit
Command
Filter Fcn
1.2
Rate
Limit
Sum Gain
Torque in
Torque out
Velocity in
Tach Out
torque - a
Tach Loop 1
position
torque - b
velocity - a
disturbance
velocity - b
2 motor mechanical system
1.96
100E-6s+1
Forward
Filter
0.84
Sum Gain1
90E-3s+1
3.5E-6s 2 +8E-3s+1
Lead
Compensator1
Velocity in
Torque out
Torque in
Tach Out
Tach Loop 2
0.488
42E-3s+1
206271
Tach Sum
Transfer
Gain12
206271
c4
Gain3
Gain4
Encoder
206271
Gain5
-KRamp
Quantizer1
Gain
Gain10
206271
Manual Switch
Step
Product
Step1
Continuous
RMS
CRMS
Mech
Present Tachometer Loop
1
Torque in
3
660E-6s+1
Sum Filter
1.33
Positive2
kk1
1
Torque out
Gain5
Gain
0.35
Constant
m
Gain6
450E-6s 2 +99E-3s
0.215
59.4E-9s 3 +121.7E-6s 2+48.7E-3s+1
220E-6s+1
Input filter Fcn3
High pass
filter Fcn1
2
Tach Out
|u|
2
Velocity in
Abs
c3
Gain4
Present Step
Present Track
Present Track with Wind
Present System Response Testing
0
Constant
1
c4
0.162s
DAC
Gain7
Integrator
0.875
470E-6s+1
Integrator
Limit
Command
Filter Fcn
1.2
Rate
Limit
Sum Gain
Torque in
Torque out
Velocity in
Tach Out
torque - a
Tach Loop 1
position
torque - b
velocity - a
disturbance
velocity - b
2 motor mechanical system
1.96
0.84
100E-6s+1
Forward
Filter
Product2
Sum Gain1
Spectrum
Analyzer1
90E-3s+1
3.5E-6s 2 +8E-3s+1
Lead
Compensator1
Velocity in
Torque out
Torque in
Tach Out
Tach Loop 2
0.488
42E-3s+1
Tach Sum
Transfer
Step3
206271
Gain2
206271
Product1
Gain12
Step2
206271
c4
Gain3
Gain4
Encoder
206271
206271
Gain1
Gain5
Spectrum
Analyzer2
Gain10
206271
Pulse
Generator
Product
Step1
Continuous
RMS
CRMS
Mech
Present Open Loop
Present Closed Loop
HA 15srcsec/sec Track
Dec 15 arcsec/sec Track
HA 600 arcsec Offset
HA 1200 arcsec Offset
Dec 1200 arcsec Offset
HA Slew
Dec Slew
Proposed System vs. Present



Delta Tau PMAC Configuration for PID
Use present Tachometer Loop
Adjust C4 gain for 16 bit DAC
Proposed System
c4
double
double
1
T
double
z
Gain7
Cycle Delay
double
z-1
Ki
double
double
Gain9
Discrete-Time
Integrator
Kp
double
double
Gain8
double
Positive
double
Velocity in
DAC
0.35
Signal
Torque in
Torque out
double
Tach Out
double
Tach Loop 1
double
0
Constant1
double
double
z2
Discrete
Transfer Fcn
z-1
Kfa
z
Discrete
Transfer Fcn1
Kfv
velocity - a
disturbance
velocity - b
double
NCD
OutPort 1
double
double
NCD_Outport1
double
Gain2
double
position
torque - b
2 motor mechanical system
Constant2
z2 -2z+1
torque - a
double
double
Negative
double
-0.35
Gain6
double
DAC1
Torque in
Torque out
double
Velocity in
Tach Out
double
Tach Loop 2
double
Constant
double
Kd
Gain1
1
double
z
Cycle Delay1
0.488
double
42E-3s+1
double
206271
Tach Sum
Transfer
double
Gain12
206271
double
double
Encoder
double
Gain4
c4
double
206271
Gain3
Gain5
double
double
Ramp
-KGain
double
double
Gain10
206271
Manual Switch
double
double
Step
doubleContinuous
Product
double
Step1
RMS
CRMS
double
Mech
double
Proposed Tachometer Loop
1
Torque in
1
kk1
660E-6s+1
1
Torque out
Gain5
Sum Filter1
450E-6s 2 +99E-3s
0.215
59.4E-9s 3 +121.7E-6s 2+48.7E-3s+1
220E-6s+1
High pass
filter Fcn1
m
|u|
Gain6
Abs
Input filter Fcn3
2
Tach Out
2
Velocity in
c3
Gain4
Proposed Step 8P
Proposed Step 35P
Proposed Step 50P
Proposed Step 100P
Proposed Track with Wind 8P
Proposed Track with Wind 35P
Proposed Track with Wind 50P
Proposed Track with Wind 100P
Proposed Track without Wind 50P
Proposed Negative Track without Wind
50P
Proposed Track without Disturbance
Rejection
Proposed System Response Testing
c4
double
1
double
T
double
z
Gain7
double
z-1
Cycle Delay
Ki
double
double
Gain9
Discrete-Time
Integrator
Kp
double
double
Gain8
double
Positive
double
Velocity in
DAC
Torque out
double
Tach Out
double
Tach Loop 1
double
0.35
Signal
Torque in
double
0
Constant1
double
z-1
Gain2
double
z
double
Product2
double
DAC1
Torque in
Torque out
double
Velocity in
Tach Out
disturbance
velocity - b
double
double
double
double
Tach Loop 2
double
-0.35
Gain6
Constant
double
double
double
double
Negative
double
Kfv
Discrete
Transfer Fcn1
velocity - a
double
Kfa
z2
Discrete
Transfer Fcn
position
torque - b
2 motor mechanical system
Constant2
z2 -2z+1
torque - a
Spectrum
Analyzer1
Kd
Gain1
1
double
0.488
double
z
42E-3s+1
double
Tach Sum
Transfer
Cycle Delay1
206271
Step3
double
Gain12
206271
double
double
Gain11
double
c4
Gain3
Encoder
double
double
206271
Product1
double
Gain4
Step2
double
206271
206271
double
Gain5
Spectrum
Analyzer2
Gain13
double
double
Gain10
206271
Pulse
Generator
double
doubleContinuous
Product
double
Step1
RMS
CRMS
double
Mech
double
Proposed Open Loop
Proposed Closed Loop
Proposed System Sweep Testing
Averaging
Spectrum
Analyzer
1
T
z
z-1
Cycle Delay
Discrete-Time
Integrator
Ki
Kp
Gain9
Gain8
Positive
0.1
Torque out
Velocity in
DAC
Tach Out
Tach Loop 1
0.35
Chirp Signal
Signal
Torque in
0
Constant1
Negative
DAC1
-0.35
Torque in
Torque out
Velocity in
Tach Out
position
torque - b
velocity - a
disturbance
velocity - b
2 motor mechanical system
Constant2
Sum Gain2
torque - a
NCD
OutPort 1
NCD_Outport1
Tach Loop 2
Constant
Kd
Gain1
1
0.488
z
42E-3s+1
Cycle Delay1
206271
Tach Sum
Transfer
Gain12
206271
Gain4
c4
Gain3
Encoder
206271
Gain5
Mech
Proposed System Sweep
Encoder Resolution
Encoder
Resolution
1
arcsec
0.5
arcsec
0.1
arcsec
0.05
arcsec
0.02
arcsec
0.01
arcsec
Present
System (track – no wind)
0.260
0.130
0.032
0.021
0.023
0.024
Present
System (step – no wind)
0.209
0.090
0.027
0.029
0.027
0.029
Present
System (track – wind)
0.319
0.217
0.160
0.156
0.153
0.152
Present
System (step – wind)
0.331
0.225
0.166
0.158
0.161
0.161
Proposed
System (track – no wind)
0.260
0.133
0.037
0.030
0.026
0.027
Proposed
System (step - no wind)
0.100
0.076
0.031
0.021
0.012
0.008
Proposed
System (track – wind)
0.258
0.150
0.091
0.088
0.088
0.088
Proposed
System (step - wind)
0.232
0.165
0.092
0.090
0.089
0.088
Conclusion




PMAC will meet 0.1 arcsec resolution
requirement
Present Encoder will meet resolution
requirement
Present Tachometer loop is necessary
Starting PID Values