The Pneumatic Biped ?Lucy? Actuated with Pleated Pneumatic Artificial Muscles

Abstract

This paper reports on the bipedal robot Lucy which is actuated by pleated pneumatic artificial muscles. This novel actuator is very suitable to be used in machines which move by means of legs. Besides its high power to weight ratio the actuator has an adaptable passive behavior, meaning the stiffness of the actuator can be changed on-line. This allows to change the natural frequency of the system while controlling angular joint positions. The main control concept intended for Lucy is joint trajectory control while selecting appropriate actuator compliance characteristics in order to reduce control efforts and energy consumption which is of great importance towards the autonomy of legged robots. Presently Lucy has made her first steps with the implementation of basic control strategies.The pleated pneumatic artificial muscle and its characteristics will be discussed briefly and the design of Lucy which is made modular on mechanical as well as electronic hardware level will be described in detail. To pressurize the muscles, a lightweight valve system has been developed which will be presented together with the fundamental control aspects of a joint actuated with two antagonistically setup artificial muscles. Additionally the first experimental results will be shown and briefly discussed.

Ein Beitrag zur Integration von Sensoren in eine anthropomorphe künstliche Hand mit flexiblen Fluidaktoren

“…Ihr Verhalten wurde in mehreren Armen [143,178,184] und Beinen [190,192] untersucht. Vorteilhaft ist hierbei, dass sich über die Differenz der Aktordrücke die Position und über die Summe der Aktordrücke die Steifigkeit des Gelenks gleichzeitig einstellen lassen.…”

HUmanoid Robotic Leg via pneumatic muscle actuators: implementation and control

“…A small number of human-inspired PMA-actuated leg setups have been proposed in the past fifteen years, with most related research addressing the structural design, modeling and control problems for undertaking motions mainly in the sagittal plane [6][7][8][9][10][11][12][13][14][15][16]. Specifically, [6] presented a robotic leg design with the ability to perform hip and knee 1-DOF motions, with antagonistic pairs of PMAs connected through tendons on the target joints, while the ankle joint remained passive.…”

“…Specifically, [6] presented a robotic leg design with the ability to perform hip and knee 1-DOF motions, with antagonistic pairs of PMAs connected through tendons on the target joints, while the ankle joint remained passive. A similar design strategy was followed in the biped humanoid presented in [7], which incorporated pleated-type PMAs in antagonistic formations to replicate the sagittal motions of the hip, knee and ankle joints. In [8] a below-knee prosthesis for the undertaking of plantar flexion ankle movements was presented, with the goal of facilitating gait patterns, where 3 pleated-type PMAs were connected via ball joints onto the metallic structure in an asymmetrical antagonistic formation.…”

“…Similarly to the techniques used in [6] and [7], researchers in [9] presented a biped prototype with the addition of bi-articular muscles to simultaneously actuate each neighbor joints ankle-knee and knee-hip. The same design techniques were also used in later efforts [9][10][11] for developing lower-limb humanoids for postural analysis and control but also restricted to the sagittal motion plane.…”

Soft Pneumatic Actuators for Rehabilitation

“…This suggests that these pneumatic actuators can be effectively used as substitutes for natural muscles. In particular they have been used for the actuation of robots that simulate human behavior [20][21][22].…”