Using sensory feedback to improve locomotion performance of the salamander robot in different environments

Motivation

Salamanders, as tetrapods which most resemble the first terrestrial vertebrates in terms of morphology, show two very distinct types of motion: walking and swimming. Models have been used at Biorob to demonstrate how the transitions between gaits are performed by the animal which eventually led to the creation of the salamander robot, which has been used as test-bed for hypothesis regarding biological concepts behind locomotion. With the creation and further development of the salamander robot, new questions regarding the locomotion control of the robot started arising, one of which is the role of sensory feedback and the possibility of using it to improve the performance of locomotion. It is now quite accepted that even though there is no need for sensory feedback to generate rythmic activity in CPGs, it is used to adjust parameters of locomotion depending on the environment. Based on the positive results of sensory feedback integration on other quadruped robots, such as Tekken2 ([1]) or the Aibo, iCub, or Ghostdog ([2]), the motivation for this project is to implement the same type of control in the salamander robot.

 control scheme

 

[1] H. Kimura, Y. Fukuoka, and A. H. Cohen. Adaptive dynamic walking of a quadruped robot on natural ground based on biological concepts. The International Journal of Robotics Research, 26:475, 2007. 

[2] L. Righetti and A. J. Ijspeert. Pattern generators with sensory feedback for the control of quadruped locomotion. Proceedings of the 2008 IEEE International Conference on Robotics and Automation (ICRA 2008), 26:819-824, May 19-23, 2008.

Original contributions

 
  1. Theoretical adaptation to the salamander robot of a feedback controller previously designed for other quadruped robots.
  2. Optimization of the open-loop controller of the salamander robot in a standard at terrain to obtain the highest speeds possible for each pair of swing and stance frequencies.
  3. Implementation of the closed-loop controller in the salamander robot to realize adaptive walking through sensory feedback.
  4. Analysis and comparison of the performance of open- and closed-loop controllers regarding speed and gait stability of the salamander robot in different environments with several degrees of difficulty.

Report and presentation