Template Composition for Synthesis of New Behaviors from Simpler Constituents Avik De Post-doctoral scholar; Ph.D. with Daniel Koditschek (2017), University of Pennsylvania Cofounder & CTO, Ghost Robotics (Philadelphia) ARL/GDRS RCTA W911NF-1020016 AFRL grant FA865015D1845 (subcontract 669737-1) ONR/OSD Vanevar Bush Fellowship N00014-16-1-2817
Legged robotics in the field: status update Vision-60 (30kg, 12dof) Research Scientific Commercial Minitaur (6kg, 8dof direct drive) Jerboa (3kg, 4dof)
Inspiration from Biology [Ting et. al. (2016)] Biology Robotics Motor abundance Multiple solutions Preferred patterns of coordination are modulated across movements Reuse modules across behaviors Facilitate multifunctionality (same muscle, different function) Manage complexity of high-dimensional robots [Ting (2007)]
• Gait control synthesis using compositions of templates • Jerboa [ICRA 2015] [ISRR 2015] [IROS 2016] [IROS 2018] • Minitaur [IJRR 2018] • Role of design in enabling compositional control • Direct-drive machines [RAL 2016] • Multifunctional design [in prep] • Analysis for understanding when it works, and providing guarantees • Hybrid averaging [IJRR 2018] • Symmetry paper [in prep] Outline = Research Agenda
Applications [Shamsah, De, Kod (IROS 2018)] [De, Kod in IJRR (2018)] Minitaur bounding, trotting, pacing, pronking Jerboa tailed hopping [De, Kod (ICRA 2014)]
Control as reduction (anchoring) + composition Classical (analytical) view Templates are themselves compositions [Full and Koditschek (1999)] “Templates and anchors…”
Preliminary observations about parameter regions Orthogonal parameter gradients • “Decoupled parameters” • Cross-product instantiation Feasible parameter regions • Composition must lie in intersection • Affects possible template behaviors [De, Kod (in prep)] Parameter space Contours of performance metric
(Hybrid) dynamical averaging as a verification tool Hybrid averaging [De, Burden, Kod in IJRR (2018)] [Raibert (1986)] Q: When can you do this? [De (2017)]
Putting together coupled systems as if they were decoupled Only terms with even* symmetry remain: Shank energy → Leg angle energy → Using all the prior ideas [De & Koditschek (in prep)] — Full dynamics — Averaged