Skin and whole-body motion of large objects with torque and position controlled humanoid robots

• Applicant: Professor Dr. Gordon Cheng
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 505597051

The goal of HoRoPo is to develop a new scientific paradigm for motion generation considering humanoid robots equipped with a skin. The aim is to manipulate large objects using torque-controlled and non-torque-controlled humanoid robots and comparing the limitations of the two approaches and to fuse them to a uniformed controller. The scientific direction will be to develop model predictive control strategies to take advantage of the skin, and the torque- and non-torque control. A scientific question to solve is the complexity arising from the number of contacts created by the object on the robot. HoRoPo will explore and exploit the potential of the skin for full-body manipulation control. It will take its foundation on the work by the German team (TUM-ICS) on the skin and the French team (LAAS-Gepetto) on whole-body predictive control. The former has realized some impressive breakthroughs in making the transmission of contact on skin patches accessible and manageable. The latter has proposed the new algorithm Crocoddyl for model predictive control for computing whole body motion for a humanoid and make MPC feasible for a torque-controlled robot with state feedback. TUM-ICS has already equipped REEM-C, a full-size humanoid robot (H1), with skin and generated whole body motion using tactile feedback without torque-control. Five years ago, LAAS-Gepetto has proposed improvements with respect to the REEM-C humanoid, in order to have a humanoid which is quite powerful and can be controlled at the torque level for the actuators. The ambition of HoRoPo is to equip a torque-controllable robot (TALOS) with skin to manipulate heavy objects and investigate a comparable strategy for non-torque-controllable humanoids (H-1). LAAS-Gepetto will extend the formulation of Croccodyl to handle multiple contacts, and modify on-line the foreseen behaviour according to the robot state. One difficulty with whole body MPC is the richness of the possible trajectory, since the algorithm can be trapped in unfeasible local minima. To cope with this, a successful approach is to use Machine Learning to learn the most likely solution for the problem through a statistical exploration of the problem. The prototype robotic skin developed at TUM-ICS provides multi-modal sensing capability, pressure, temperature, acceleration. It has already been used to cover their humanoid H-1 for research on balancing and walking control, including a software framework. In HoRoPo, we will join forces with LAAS to work on extending this capability to whole-body manipulation. TUM-ICS will focus on contacts detection and multi-contacts-based control of a humanoid robot with position or torque control capabilities. The new control schemes developed in HoRoPo will open up a new line of humanoid robotic research. Such advanced technologies will have an impact that will go far beyond humanoid robotics to date and will increase the use of these robots across multiple application domains.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partner: Privatdozent Olivier Stasse, Ph.D.