Software Development for Automated Measurement and Analysis of Spring Characteristics in Serial Elastic Robotic Actuators

Abstract

The Institute of Robotics and Mechatronics of the German Aerospace Center researches biological locomotion and applies the insights to robotic locomotion by developing the quadrupedal robot Bert. Bert's drives are Serial Elastic Actuators, which use a spring as elastic component [13]. These springs play a significant role in the robot's dynamic behavior, thus determining their characteristics is crucial. To measure these characteristics, a software system for the spring testbed of the Institute of Robotics and Mechatronics is developed within the scope of this thesis. The developed software system covers all aspects to setup and perform test procedures including control and communication of all hardware components. The testbed software system is built on the Links and Nodes middleware of the Institute of Robotics and Mechatronics and utilizes its process control and interprocess communication. The modular software framework Robotkernel, developed at the Institute, is used to interface to the hardware components and publishes and receives data using the Links and Nodes functionalities. In order to simultaneously execute, control, and record test procedures, the developed software system applies a Client-Server structure, in which each task is handled by an individual server. The services of the servers are called using a new Python scripting library that is also implemented in the scope of this thesis. This scripting library together with the graphical user interface offers the interface for setup and operation of the testbed. The developed testbed software system is already applied to measure the characteristics of springs built into a robotic leg prototype for Bert.