MACCEPA: the Actuator with Adaptable Compliance for Dynamic Walking Bipeds

Abstract

Walking robots can be divided into two categories: on one hand the fully actuated robots that don't use passive dynamics, and on the other hand the energy efficient passive walkers. For autonomous robots the energy storage is a problem, forecasting a bright future for passive walkers. At this moment the passive walkers are restricted to one walking speed due to the eigenfrequency, which is fixed by the mechanical constructions. Several actuators with adaptable compliant have been designed, but due to size, complexity or controllability these are difficult to implement in mpliance ca for dynamic walking, human-robotic interfaces and robotic rehabilitation devices. mpliance, Equilibrium Position, Actuators, Compliance control, Spring bipeds. Another application of the use of adaptable compliance is safe robothuman interaction. Sometimes a robot has to be stiff, e.g. for pick and place operations, but when moving between humans, a robot is preferably compliant. Also for exoskeletons or rehabilitation devices this co n improve ergonomics and speed up the rehabilitation process. The MACCEPA is a straightforward and easy to construct rotational actuator, of which the compliance can be controlled separately from the equilibrium position. The generated torque is a linear function of the compliance and of the angle between equilibrium position and actual position. This makes this actuator perfectly suitable

Advanced Swing Leg Control for Stable Locomotion

“…Similar adjustments of elastic properties have already been implemented in technical legs [4]. In the present study we propose a linear stiffness change of the leg during swing phase in addition to swing-leg retraction.…”

Double actuation architectures for rendering variable impedance in compliant robots: A review

“…In the Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator (MACCEPA, [55]) the stiffness variation is achieved by changing the pretension of a spring.…”

Mechanism and Control of Continuous-State Coupled Elastic Actuation

“…Recently, several safe and efficient robot actuation techniques have been proposed, such as series elastic actuators (SEAs) [6][7][8][9][10][11][12][13], programmed impedance actuators [14,15], and variable stiffness actuators [15][16][17][18][19][20][21][22]. In all these designs, a critical feature is the stiffness of the series elastic component, which dominates the bandwidth and the payload capacity of the overall system, and therefore the safety level in the pHRI field.…”