18 KiB
18 KiB
Simscape Model - Nano Active Stabilization System
- Introduction
- Control Kinematics
- Decentralized Active Damping
- Centralized Active Vibration Control
- Conclusion
- Bibliography
Introduction ignore
From last sections:
- Uniaxial: No stiff nano-hexapod (should also demonstrate that here)
- Rotating: No soft nano-hexapod, Decentralized IFF can be used robustly by adding parallel stiffness
In this section:
- Take the model of the nano-hexapod with stiffness 1um/N
- Apply decentralized IFF
- Apply HAC-LAC
- Check robustness to payload change
- Simulation of experiments
| Sections | Matlab File |
|---|---|
| Section ref:sec:nass_1_a | nass_1_.m |
Control Kinematics
<<sec:nass_kinematics>>
Introduction ignore
- Explain how the position error can be expressed in the frame of the nano-hexapod
- positioning_error: Explain how the NASS control is made (computation of the wanted position, measurement of the sample position, computation of the errors)
- Control architecture, block diagram
- Schematic with micro-station + nass + metrology + control system
- Zoom in the control system with blocs
- Then explain all the blocs
- Say that there are many control strategies. It will be the topic of chapter 2.3. Here, we start with something simple: control in the frame of the struts
Micro Station Kinematics
- from ref:ssec:ustation_kinematics, computation of the wanted sample pose from the setpoint of each stage.
Computation of the sample's pose error
From metrology (here supposed to be perfect 6-DoF), compute the sample's pose error. Has to invert the homogeneous transformation.
Position error in the frame of the nano-hexapod
Explain how to compute the errors in the frame of the struts (rotating)
Decentralized Active Damping
<<sec:nass_active_damping>>
Introduction ignore
- How to apply/optimize IFF on an hexapod? ()
- Robustness to payload mass
- Root Locus
- Damping optimization
- [ ]control_active_damping
- [ ]active damping for stewart platforms
- [ ]Vibration Control and Active Damping
IFF Plant
- Show how it changes with the payload mass (1, 25, 50)
- Effect of rotation (1rpm, 60rpm)
Controller Design
- Apply IFF
- Show Root Locus
- Choose optimal gain. Here in MIMO, cannot have optimal damping for all modes. (there is a paper that tries to optimize that)
- Show robustness to change of payload (loci?)
- Reference to paper showing stability in MIMO for decentralized IFF
Sensitivity to disturbances
- Compute transfer functions from spindle vertical error to sample vertical error with IFF (and compare without the NASS)
- Same for horizontal
- Maybe noise budgeting, but may be complex in MIMO…
Centralized Active Vibration Control
<<sec:nass_hac>>
Introduction ignore
- uncertainty_experiment: Effect of experimental conditions on the plant (payload mass, Ry position, Rz position, Rz velocity, etc…)
- Effect of micro-station compliance
- Effect of IFF
- Effect of payload mass
- Decoupled plant
- Controller design
From control kinematics:
- Talk about issue of not estimating Rz from external metrology? (maybe could be nice to discuss that during the experiments!)
- Show what happens is Rz is not estimated (for instance supposed equaled to zero => increased coupling)
HAC Plant
- Compute transfer function from u to dL (with IFF applied)
Effect of Payload mass
- Show effect of payload mass + rotation
Controller design
- Show robustness with Loci
Sensitivity to disturbances
- Compute transfer functions from spindle vertical error to sample vertical error with HAC-IFF Compare without the NASS, and with just IFF
- Same for horizontal
- Maybe noise budgeting, but may be complex in MIMO…
Tomography experiment
- With HAC-IFF, perform tomography experiment, and compare with open-loop
- Take into account disturbances, metrology sensor noise. Maybe say here that we don't take in account other noise sources as they will be optimized latter (detail design phase)
- Tomography + lateral scans (same as what was done in open loop here)
- Validation of concept
Conclusion
<<sec:nass_conclusion>>