tailieunhanh - Humanoid Robots Human-like Machines Part 4

Tham khảo tài liệu 'humanoid robots human-like machines part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Artificial Muscles for Humanoid Robots 111 a b Figure 11. Roll actuator composed of rolled dielectric elastomers a - from Pei et al. 2003 -and application of this technology to the actuation of an anthropomorphic arm in the framework of the NASA s armwrestling contest - from NASA web site see the three big roll actuators inside the purple box in b b Figure 12. Pleated artificial muscle applied to biped robots a Static characteristics of the pleated artificial muscle b Corresponding antagonist actuator showing the difficulty to place simultaneously the two inflated muscles into antagonism c Lucy biped robot moving in a vertical plane from Lucy web site c 112 Humanoid Robots Human-like Machines a b Figure 13. Two examples of anthropomorphic robot-arm design actuated by pneumatic McKibben muscles a shadow robot-arm equipped with shadow hand showing artificial shoulder musculature placed in the robot s waist from Shadow Robot Group web site b 7R anthropomorphic robot-arm prototype built in the laboratory with 30 cm horizontal shoulder muscles developing a maximum force exceeding 500 dN 5. Control of anthropomorphic limbs actuated by skeletal artificial muscles Non-linearities of robot joints actuated by artificial muscle actuators The use of flexible materials such as the recourse to original stimulus modes pH solvent heat etc. are complexity factors of the physical models of any artificial muscle actuator. What results is a non-linear character generally more manifest than for other robotic actuators. In particular it is well known that the more nonlinear the plant the more imprecise its physical or identified model on which its control can be based. Using Slotine Li terminology Slotine Li 1991 the artificial muscle actuator is more concerned than others by structured or parametric uncertainties as by unstructured uncertainties or unmodelled dynamics . Furthermore in the case of robot-limbs actuated by artificial muscles the specific actuator non-linearities enter