Design and evaluation of a serial elastic actuator for human assistance

In this article, the systematic development of a serial elastic actuator for human assistance is presented. First, requirements for the actuator are deduced from the specific application, as part of an assistance robots for partially paralyzed patients. A test bench was developed to evaluate the serial elastic actuator under various conditions and to produce reference sensor data. The device was tested in four different scenarios, ranging from stiff fixation of the output to interaction with the knee joint of an active or passive human test subject. A variable system inherent friction was identified and the potential of this (usually undesired) characteristic is discussed for the special case of human assistance.