Title :
Actuator design for high force proprioceptive control in fast legged locomotion
Author :
Seok, Sangok ; Wang, Albert ; Otten, David ; Kim, Sangbae
Author_Institution :
Dept. of Mech. Eng., Massachusetts Inst. of Technol., Cambridge, MA, USA
Abstract :
High speed legged locomotion involves high acceleration and extensive loadings of the leg, which impose critical challenges in actuator design. We introduce actuator dimensional analysis for maximizing torque density and transmission `transparency´. A front leg prototype developed based on insight from the analysis is evaluated for direct proprioceptive force control without force sensors. The vertical stiffness controlled leg was tested on a material testing device to calibrate the mechanical impedance of the leg. By compensating transmission impedance from commanded torque, the leg was able to estimate impact force. For the impact test, the mean absolute error as a ratio of full scale sensor force is 0.041 in the 3406 N/m stiffness experiment and is 0.049 in the 5038 N/m experiment. The results indicate that prescribed force profile control is possible during high speed locomotion.
Keywords :
actuators; force control; impact (mechanical); legged locomotion; materials testing; mechanoception; actuator design; actuator dimensional analysis; commanded torque; critical challenges; direct proprioceptive force control; fast legged locomotion; force profile control; full scale sensor force; high acceleration; high force proprioceptive control; high speed legged locomotion; high speed locomotion; impact force; material testing device; mean absolute error; mechanical impedance; stiffness experiment; torque density; transmission impedance; Actuators; Brushless motors; Force; Gears; Impedance; Legged locomotion; Torque;
Conference_Titel :
Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on
Conference_Location :
Vilamoura
Print_ISBN :
978-1-4673-1737-5
DOI :
10.1109/IROS.2012.6386252