sightline servo control technology
TRANSCRIPT
Sightline Servo Control Technology
Matt MacDonald
Selex Technical Fellow
Sightline Control and Navigation Systems Design Group Leader
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Contents
Introduction
Technology Heritage
Technology Competencies
Servo Design & Development
Future
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Introduction
Both EO and Radar products essentially consist of 3 key sub-systems:
Receiver - EO Camera, Quad diode or Radar Rx etc
Transmitter - Laser or Radar Tx
Beam Pointing - Gimbal, stabilised mirror, Radar ESCAN array etc
Edinburgh has a vast Ferranti-era design heritage in pointing servos from both the EO Targeting and Radar sectors of the business – see next two slides
Servo engineering has been a core EO systems integration specialism since the founding of the Edinburgh based EO business in 1966
Basildon has also had a notable presence in EO Servo products such as MRT, Sea Owl, Titan and the Stormshadow seeker head.
With over 1500 DIRCM Transmitter units delivered into service, the next generation MPT now in low rate production and the latest Eclipse/SPT system in the development pipeline, Selex in Edinburgh has the leading DIRCM sightline servo control capability in the World
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FERRANTI SCOTLAND – EO & NAV HERITAGE Is
t_E
_X
XX
XX
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FERRANTI SCOTLAND - RADAR HERITAGE
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EO Pointing System Heritage - Basildon
MRT
ALLTV
SEA-OWL
Titan 385
Stormshadow
Missile Seeker Head
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Laser DIRCM Product Line
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Technology Competencies
Control Theory Domain Knowledge: Sightline Pointing, Tracking and Stabilisation
Simulation and modelling Component technical Knowledge – motors, encoders, IMUs
Key component Vendor knowledge Mechanism Design Knowledge Sightline and Control Systems Test knowledge General Systems Engineering Knowledge: From spec-it to sell-off
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Servo Systems Design
Ideally a Model Driven Process
Practically model referenced at least
Key requirements are: Pointing Accuracy
Slew time
Tracking accuracy
Sightline Jitter
Achieving these requirements over
the full environmental envelope is
nearly always a significant challenge
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System
Requirements
Specification
Sightline Sub-
system Budget
(Model)
Static Pointing Errors (Optical Engineering)Structural deflection Errors (Mech Eng)
Test Equipment Accuracy (TE Eng)
SIMULINK
MODEL
Servo Rapid
Prototype
Control Tests
(Servo X-model)
Rapid Prototype
Performance Tests(Servo X-model)
Components &
Mechanism
Requirements
Specs
Full Development
Project
DSP/FPGA based
HardwareTarget
Servo Component &
Mechanism
Testing
(System Identification)
Sightline Servo Rapid Development Process
Servo Design
DocumentOpen-loop frequency response
Gain/Phase Margins
Step response etc
Full Tracking/stabilisation
Performance Tests under
temp/vib/OSM
Full Development
Integration
Early System
Performance Risk
Management
information to Project
Support
Sightline Servo
Subsystem Reqts Spec
ICDTest/Verfification
Spec
Representative
Servomechanism
Supplied by
Project
Validate
Verify
Verify
Validate
LabVIEW SIT
C-code/
SYSGEN
Plant Model
Validation
Design
Rapid Prototype TestPlant & Servo
Experimental Rig
(X-model)
Procure Mechanism
Plant Transfer Function
Friction & OoB tests
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Servo Systems Development
Testing and model validation are the keys to a successful Servo Systems Engineering development:
Component testing
Mechanism “plant identification” testing
Servo model validation testing
Xperimental model performance testing
Fully Configured System performance testing
Environmental testing
Possibly “Test Driven and Model Referenced” would be a better description of the Servo development process?
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Component/sub-system Testing - Motor & Drive Control
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Servo Rapid Prototyping – the X-model
Objectives: To test that the
mechanism design meets its spec
and to validate/develop the overall
control systems model
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Servo Lab
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The Future
Radar ESCAN technology has reduced the need for mechanical beam steering – but not entirely
EO solid-state beam pointing based on optical phased array technology currently tends to have significant FoR and/or wavelength limitations
DIRCM and Advanced Targeting applications tend to demand hyper-hemispherical beam pointing
Conventional servomechanism based EO Sightline beam pointing is expected to remain an important core technology in this domain for many years to come