Deployer with Retrievable Capability for Space Applications 1 st - PowerPoint PPT Presentation

Modeling a New Concept of Tether Deployer with Retrievable Capability for Space Applications 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015 Gilberto Grassi ⋆ , Riccardo Mantellato ⋆ MSc Aerospace Engineering Department of Industrial Engineering University of Padova

Overview 1. Introduction 2. Proposed concept 3. Models & control 4. Simulations 5. Conclusions 1 st Symposium on Space Educational Activities 2 of 24 Padova, December 11 th , 2015

Introduction 1 st Symposium on Space Educational Activities 3 of 24 Padova, December 11 th , 2015

Scope & Requirements What did we want to do? 1. Model a tether deployer with retrievable capability 2. Simple & reliable 3. Compact & light 1 st Symposium on Space Educational Activities 4 of 24 Padova, December 11 th , 2015

Tether heritage (1/2) 1992 – TSS-1 – 20 km tether  670 kg satellite + tether  4800 kg pallet & support 1 st Symposium on Space Educational Activities 5 of 24 Padova, December 11 th , 2015

Tether heritage (2/2) 1994 – SEDS-II – 20 km tether  33 kg tip mass + tether  10 kg deployer hardware 1 st Symposium on Space Educational Activities 6 of 24 Padova, December 11 th , 2015

Proposed concept 1 st Symposium on Space Educational Activities 7 of 24 Padova, December 11 th , 2015

Proposed concept (1/2) Fixed spool Openable bail 1 st Symposium on Space Educational Activities 8 of 24 Padova, December 11 th , 2015

Proposed concept (1/2) Tether Deployment phase Fixed spool Openable bail 1 st Symposium on Space Educational Activities 8 of 24 Padova, December 11 th , 2015

Proposed concept (1/2) Tether Retrieval phase Fixed spool DC motor Openable bail 1 st Symposium on Space Educational Activities 8 of 24 Padova, December 11 th , 2015

Proposed concept (2/2) How to control tether motion during deployment? Low-Inertia (SEDS- like)… … Inductive Brake (TSS-like) PD control 1 st Symposium on Space Educational Activities 9 of 24 Padova, December 11 th , 2015

Proposed concept (2/2) How to control tether motion during deployment? Low-Inertia (SEDS- like)… … Inductive Brake (TSS-like) PD control 1 st Symposium on Space Educational Activities 9 of 24 Padova, December 11 th , 2015

Proposed concept (2/2) How to control tether motion during deployment? Low-Inertia (SEDS- like)… … Inductive Brake (TSS-like) PD control 1 st Symposium on Space Educational Activities 9 of 24 Padova, December 11 th , 2015

Models & control 1 st Symposium on Space Educational Activities 10 of 24 Padova, December 11 th , 2015

Models (1/2) Dumbbell tether model � M z l θ x m y 1 st Symposium on Space Educational Activities 11 of 24 Padova, December 11 th , 2015

Models (2/2) Mechanical brake (low-inertia) Rollers Friction Motion Tether Actuator x 1 st Symposium on Space Educational Activities 12 of 24 Padova, December 11 th , 2015

Control (1/2) Reference trajectory optimization – Nelder-Mead algorithm 1 st Symposium on Space Educational Activities 13 of 24 Padova, December 11 th , 2015

Control (2/2) . Reference trajectories feed-forward – l ref (t), l ref (t) . l ref (t), l ref (t) . l , l Tether/probe - dynamics ε control tension T PD controller 1 st Symposium on Space Educational Activities 14 of 24 Padova, December 11 th , 2015

Equations (deployment) LI IB 1 st Symposium on Space Educational Activities 15 of 24 Padova, December 11 th , 2015

Equations (deployment) LI Control Inner friction IB 1 st Symposium on Space Educational Activities 15 of 24 Padova, December 11 th , 2015

Equations (deployment) LI 15 mN Control Inner friction IB 150 mN 1 st Symposium on Space Educational Activities 15 of 24 Padova, December 11 th , 2015

Simulations 1 st Symposium on Space Educational Activities 16 of 24 Padova, December 11 th , 2015

Deployment scenario (1/2) x E.g. active debris removal local vertical z Target Chaser 1 st Symposium on Space Educational Activities 17 of 24 Padova, December 11 th , 2015

Deployment scenario (1/2) x E.g. active debris removal local vertical z Target Chaser 1 st Symposium on Space Educational Activities 17 of 24 Padova, December 11 th , 2015

Deployment scenario (1/2) x E.g. active debris removal local vertical Target Tethered Chaser de-orbit package 1 st Symposium on Space Educational Activities 17 of 24 Padova, December 11 th , 2015

Deployment scenario (2/2) 1 st Symposium on Space Educational Activities 18 of 24 Padova, December 11 th , 2015

Deployment scenario (2/2) θ 0 . l 0 l goal 1 st Symposium on Space Educational Activities 18 of 24 Padova, December 11 th , 2015

Results Simulations results ( ): successful deployments ( ): insufficient brake authority control ( ): insufficient initial velocity 1 st Symposium on Space Educational Activities 19 of 24 Padova, December 11 th , 2015

Results Simulations results Required higher launch velocity ( ): successful deployments ( ): insufficient brake authority control ( ): insufficient initial velocity 1 st Symposium on Space Educational Activities 19 of 24 Padova, December 11 th , 2015

Results Simulations results Less control authority w.r.t. IB ( ): successful deployments ( ): insufficient brake authority control ( ): insufficient initial velocity 1 st Symposium on Space Educational Activities 19 of 24 Padova, December 11 th , 2015

Deployment example (1/3) Successful deployment 1 st Symposium on Space Educational Activities 20 of 24 Padova, December 11 th , 2015

Deployment example (2/3) Deployment failure – insufficient launch velocity 1 st Symposium on Space Educational Activities 21 of 24 Padova, December 11 th , 2015

Deployment example (3/3) Deployment failure – insufficient deployer control authority 1 st Symposium on Space Educational Activities 22 of 24 Padova, December 11 th , 2015

Conclusions 1 st Symposium on Space Educational Activities 23 of 24 Padova, December 11 th , 2015

Conclusions Inductive brake Low-inertia 1. More control authority 1. Easier ground test phase 2. Requires less energy ( T 0 ) 2. Less actuators 3. Some critical issues during 3. Higher tolerance of design deployment are addressed inaccuracies (less parts in synch. motion) 1 st Symposium on Space Educational Activities 24 of 24 Padova, December 11 th , 2015

Conclusions Inductive brake Low-inertia 1. More control authority 1. Easier ground test phase 2. Requires less energy ( T 0 ) 2. Less actuators 3. Some critical issues during 3. Higher tolerance of design deployment are addressed inaccuracies (less parts in synch. motion) 1 st Symposium on Space Educational Activities 24 of 24 Padova, December 11 th , 2015

- Questions? -

Extras – YES2 2007 – YES2  12 kg endmass + tether  24 kg deployment hardware

Extras – motion equations 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – motion equations Tether tension Gravity gradient (control) Convective Centrifugal . Stabilizing if l > 0 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – system parameters Low-inertia Inductive brake Higher inner friction in IB due to more sliding parts 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – deployment scenario LV LV T@bod Relative T@eo motion d Easier deployment No relative motion but higher v rel @eod! T@bod ≡ T@eod LH LH C C 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – deployment scenarios θ 0 values chosen in the simulations 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – Nelder-Mead algorithm 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – Nelder-Mead algorithm 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – abort capability 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – mechanical brake Mechanical brake 2 α x p α d 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – models α p α d/p = 3 2 α x d x 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – models α p α d/p = 3 60° 2 α x d x 9 cm 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – applications What could we do? New docking techniques 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015

Extras – DC motor R J � τ V 1 st Symposium on Space Educational Activities Padova, December 11 th , 2015