Master Project Design and simulation of locomotion of - PowerPoint PPT Presentation

Master Project Design and simulation of locomotion of self-organising modular robots for adaptive furniture Rafael Arco Arredondo < rafael.arcoarredondo@epfl.ch > Supervisor: Prof. Auke Jan Ijspeert Biologically Inspired Robotics Group (BIRG) Swiss Federal Institute of Technology Lausanne (EPFL) 19th July 2006 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 1 / 28

The Roombots project Development of modular robots for adaptive and self-organising furniture for the new Learning Centre at the EPFL: Design of the prototypes of the modules Control of locomotion Self-reconfiguration User interface (LASA) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 2 / 28

Overview Design of the modules (with S. Cevey) Simulation of locomotion Design of some multi-unit robots (with S. Cevey) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 3 / 28

Overview Online optimisation of Adaptation to the terrain locomotion using reflexes Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 3 / 28

Outline Background 1 Design of the modules 2 Control of locomotion 3 Conclusions and future work 4 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 4 / 28

Outline Background 1 Design of the modules 2 Control of locomotion 3 Conclusions and future work 4 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 5 / 28

Modular Robotics Design of complex robots out of simple building blocks (modules): Simplicity Homogeneity Flexibility Reliability Adaptability Low cost Origins in Karl Sims’ creatures (1994) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 6 / 28

Modular Robotics: examples M-TRAN (AIST): Polybot (PARC): Conro (USC): YaMoR (BIRG): Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 7 / 28

Control of locomotion with CPGs Central Pattern Generators are responsible of locomotion in chordates (Grillner, 70’s) Neural networks in the spinal cord which produce the necessary rhythms for locomotion Modulation with simple signals (gait transition, control of amplitude and frequency, adaptation) Successfully applied to Modular Robotics (M-TRAN) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 8 / 28

Outline Background 1 Design of the modules 2 Control of locomotion 3 Conclusions and future work 4 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 9 / 28

Characterisation of the modules: requirements and decisions Main design constraints adopted: Homogeneous modules Two orthogonal DOFs Requisites the robots must fulfill: Strong attachment mechanisms (no magnets), Simple control with 4 orientations (0 ◦ , 90 ◦ , Locomotion 180 ◦ and 270 ◦ ) Reconfiguration Dimensions suitable for Self-organisation, adaptation furniture Use as real furniture Static pieces (e.g. the top of a table) Webots+ODE to model the robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 10 / 28

The universal joint module Two identical boxes linked by a universal joint (two perpendicular DOFs) Each DOF can rotate in [ − 90 ◦ , + 90 ◦ ] In principle, 10 attachment points Dimensions: ∼ 24 × 8 × 8 cm (12 × 8 × 8 cm each box) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 11 / 28

The wheeled module One big box and one smaller one that has a wheel (inscribed or circumscribed) on one of the faces Two DOFs: one rotates the small box+wheel group on the vertical plane, the other rotates the wheel on the horizontal plane The small box+wheel can rotate in [ − 112 . 5 ◦ , + 112 . 5 ◦ ] , the wheel rotates freely with no limits 14 attachment points Dimensions: 24 × 8 × 8 cm (16 × 8 × 8 cm the big box, 6 × 8 × 8 cm the small one) Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 12 / 28

Attachments Hermaphrodite: Should: ◮ Be mechanical ◮ Be strong enough to hold the weight of the structure and a person ◮ Need energy just at the moment of attaching/detaching, not to be maintained ◮ Ideally be hermaphrodite, although male/female connectors still offer high Male/female: flexibility Use of docking stations To be studied in further work Simulations done with hermaphrodite connectors abstracting mechanical details Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 13 / 28

Multi-unit robots Pre-defined pieces of furniture: Transient configurations (e.g. during reconfiguration): Fast creation in Webots with the library robot-positioning Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28

Pre-defined pieces of furniture: Multi-unit robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28

iture: Multi-unit robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28

Multi-unit robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28

Multi-unit robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28 configurations (e.g. during

Multi-unit robots Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 14 / 28 during reconfiguration):

Outline Background 1 Design of the modules 2 Control of locomotion 3 Conclusions and future work 4 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 15 / 28

The Matsuoka oscillator τ ˙ u { e , f } = u 0 − u { e , f } + w fe y { f , e } − β v { e , f } For u 0 = 2 . 05, β = 2 . 5, τ = 0 . 13, τ ′ = 0 . 26, w fe = − 2 . 0 τ ′ ˙ v { e , f } = y { e , f } − v { e , f } y { e , f } = max ( u { e , f } , 0 ) 1 0.8 y osc = y f − y e 0.6 0.4 0.2 output 0 Extensor neuron τ ′ τ −0.2 −0.4 β u 0 u e v e −0.6 −0.8 −1 0 1 2 3 4 5 6 7 8 9 10 time [s] y e = max ( u e , 0 ) 0.7 − w fe y osc 0.6 + 0.5 y f = max ( u f , 0 ) 0.4 v f 0.3 0.2 u 0 u f v f β 0.1 τ ′ 0 τ Flexor neuron −0.1 −1.5 −1 −0.5 0 0.5 1 1.5 excitatory inhibitory u f connection connection Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 16 / 28

Couplings between oscillators � τ ˙ u i , { e , f } = u 0 − u i , { e , f } + w fe y i , { f , e } − β v i , { e , f } + w ij y j , { e , f } j Phase difference between two Structure of the CPG for the oscillators: pieces of furniture: w ij h fr h hr i j w ji 1 h fl h hl 6 0.8 0.6 5 0.4 4 0.2 k fr k hr w 21 0 3 −0.2 2 −0.4 k fl k hl −0.6 1 −0.8 −1 0 −1 −0.8 −0.6 −0.4 −0.2 0 0.2 0.4 0.6 0.8 1 w 12 Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 17 / 28

Exploration of different locomotion gaits Gait θ fl θ hl θ fr θ hr Walk 0 π 3 π/ 2 π/ 2 Trot 0 π π 0 Bound 0 π 0 π u 0 = 2 . 05 , β = 3 . 0 , w fe = − 2 . 0 , τ = 0 . 1 , τ ′ = 0 . 3 Pace 0 0 π π Jump 0 π/ 2 0 π/ 2 Pronk 0 0 0 0 Trot: -0.3 -0.5 k fl fr -0.4 -0.4 +0.4 +0.4 -0.4 -0.8 -0.4 -0.8 -0.5 hl hr 1 flh hlh 0.8 flk 0.6 0.4 0.2 output 0 −0.2 −0.4 −0.6 −0.8 −1 0 5 10 15 time [s] Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 18 / 28

Exploration of different locomotion gaits Gait θ fl θ hl θ fr θ hr Walk 0 π 3 π/ 2 π/ 2 Trot 0 π π 0 Bound 0 π 0 π u 0 = 2 . 05 , β = 3 . 0 , w fe = − 2 . 0 , τ = 0 . 1 , τ ′ = 0 . 3 Pace 0 0 π π Jump 0 π/ 2 0 π/ 2 Pronk 0 0 0 0 Walk: +0.5 -0.2 -0.5 k fl fr +0.2 +0.8 -0.4 +0.8 -0.4 +0.5 hl hr -0.5 1 flh hlh 0.8 frh hrh 0.6 0.4 0.2 output 0 −0.2 −0.4 −0.6 −0.8 −1 0 5 10 15 time [s] Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 18 / 28

Exploration of different locomotion gaits Gait θ fl θ hl θ fr θ hr Walk 0 π 3 π/ 2 π/ 2 Trot 0 π π 0 Bound 0 π 0 π u 0 = 2 . 05 , β = 3 . 0 , w fe = − 2 . 0 , τ = 0 . 1 , τ ′ = 0 . 3 Pace 0 0 π π Jump 0 π/ 2 0 π/ 2 Pronk 0 0 0 0 Bound: -0.3 +0.1 k fl fr -0.5 +0.5 -0.5 +0.5 -0.5 +0.1 hl hr 1 flh hlh 0.8 0.6 0.4 0.2 output 0 −0.2 −0.4 −0.6 −0.8 −1 0 5 10 15 time [s] Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 18 / 28

Exploration of different locomotion gaits Gait transitions: Trot to bound: Trot to walk: 1 flh 1 flh frh frh 0.8 0.8 hrh 0.6 0.6 0.4 0.4 0.2 0.2 output output 0 0 −0.2 −0.2 −0.4 −0.4 −0.6 −0.6 −0.8 −0.8 −1 −1 20 22 24 26 28 30 32 34 36 38 40 15 20 25 30 35 time [s] time [s] Rafael Arco Arredondo (BIRG, EPFL) Roombots, MR for adaptive furniture 19th July 2006 18 / 28