Transcript NTNU
Walking Robots Dr. Leonid Paramonov Course: TTK6 – Robotics 13.09.2013 Talk overview Review of state of the art in walking robots Current walking robot project at ITK NTNU (student project opportunities) Walking robots classification “Quasi-static” humanoid robots or the ones based on typical topology of industrial robots 2 dimensional walkers Based on passive walking mechanisms Biologically inspired robots Dynamic multi-pedal robots * the current tendency in the field is in slow merging of different types of walking robot concepts Quasi-static topology Probably above 90% of all existing walking robots and the absolute majority of DIY robotics Relying on static stability of the structure depending on position of the centre of mass of the robot above robot's footprint In a sense the dynamical forces are not desired here because they mess up the stability (design conflict) Coordinated motion of multiple DoF's Difficulty in motion planning which is in many cases just pre-recorded trajectories Recent advances in the field Why industrial robot topology? Typical design – rigid links with cylindrical joints as DoFs controlled by geared DC/brushless motors Often the dynamical trajectory planning for industrial applications requires compensation of the dynamic forces to “free” the robot for a trajectory following task Conceptual problems of this robot topology The worst possible place for a torque actuator Effective inertia of the geared actuators JE = n2 * J, where n is the gearbox ratio Design - “exponential law” Asimo, Honda In development since 1980s Very impressive recent developments like running, hopping High power legs by JSK Lab, Tokyo University Humanoid robots by Kawada Industries Inc. Closely related to JSK Lab in University Tokyo Viki humanoid by SDU, Odense, Denmark World champion in CoboCup 2002 free style competitions Petman, Boston Dynamics Atlas, Boston Dynamics Is being currently developed for DARPA Robotics Challenge 2D “Pole walkers” Spring Flamingo, MIT, Leg Lab 2D “Pole walkers” Rabbit, Grenoble, France 2D “Pole walkers” MABLE, University of Michigan Passive walkers Walking down a small inclination slope using potential energy Passive walkers Research passive walkers - energy efficient periodic gaits Actuated walkers using mechanical principles close to passive ones (example “Ranger” marathon walker by Cornell University) Biologically inspired dynamic walkers/runners (not only bipeds) Elastic compliant actuators, biologically inspired mechanical structures, dynamic periodic gaits Boston Dynamics: Big Dog, RoboMule, Cheetah (fastest running robot on Earth) Biologically inspired dynamic walkers/runners (not only bipeds) The Big Dog robot Biologically inspired dynamic walkers/runners (not only bipeds) The RoboMule robot Biologically inspired dynamic walkers/runners (not only bipeds) The Cheetah robot Biologically inspired dynamic walkers/runners (not only bipeds) MIT Cheetah robot Cheetah cub robot by EPFL Walking robot project Existing theoretical result for 2D walker Walking robot project 2D “Pole walker”, 2 passive degrees of freedom, 1 actuator Theoretical challenges Nonlinear control of periodic motions Trajectory planning with ground collisions Controller design Walking robot project Design challenges Purpose built for verification of a specific theoretical results Direct drive actuator without gear Integration Experiments