Combining series elastic actuation and magneto-rheological damping for the control of agile locomotion

All-terrain robot locomotion is an active topic of research. Search and rescue maneuvers and exploratory missions could benefit from robots with the abilities of real animals. However, technological barriers exist to ultimately achieving the actuation system, which is able to meet the exigent requirements of these robots. This paper describes the locomotioncontrol of a leg prototype, designed and developed to make a quadruped walk dynamically while exhibiting compliant interaction with the environment. The actuation system of the leg is based on the hybrid use of series elasticity and magneto-rheological dampers, which provide variable compliance for natural-looking motion and improved interaction with the ground. The locomotioncontrol architecture has been proposed to exploit natural leg dynamics in order to improve energy efficiency. Results show that the controller achieves a significant reduction in energy consumption during the leg swing phase thanks to the exploitation of inherent leg dynamics. Added to this, experiments with the real leg prototype show that the combined use of series elasticity and magneto-rheologicaldamping at the knee provide a 20 % reduction in the energy wasted in braking the knee during its extension in the leg stance phase

Study of neutron-proton interaction in the 300--700 MeV energy region. Final progress report, July 1991--August 1994

The experimental program supported by the present grant is a continuation of the work supported under DOE Contract DE-AS05-76ER04449. More detailed discussion of the experimental apparatus and earlier activities can be found in annual reports for that contract and this grant. The primary objective of this program is investigation of the nucleon-nucleon (NN) interaction, in the medium-energy region, in both elastic and inelastic channels

Measurement of K/sub NN/ and K/sub LL/ in p vector p. -->. n vector X at 800 MeV

The spin transfer parameters, K/sub NN/ and K/sub LL/ have been measured in p vector p ..-->.. n vector X at 0/sup 0/ and 800 MeV for neutron momenta between 700 and 1200 MeV/c. Peak values of K/sub NN/ and K/sub LL/ are -.3 +- .05 and -.5 +- .1, respectively