Researchers at the Italian Institute of Technology have developed an underactuated flying humanoid robot that has Iron Man-style jet propulsion system. These types of robots may have thousands of applications of its own like performing inspections or repairs, or might help in developing human flight exoskeleton.
The very first step is developing control framework for underactuated flying humanoid robots. They have capabilities of flight and contact locomotion and advantages of technologies, especially developed for aerial manipulation and full-body control.
The robot is powered by 4 thrust forces placed at the robot’s feet and hands. The controls are based on asymptotic stabilization of the robot centroidal momentum, which would allow us to track robot’s centre of mass trajectory.
The research team is still working at the theoretical stage and they hope to put their discoveries into practice very soon.
Daniele Pucci, lead author, came up with the idea 4 years ago. ‘Richard Browning recent successful story demonstrates futuristic actuated exoskeletons. We’ve invited Richard to IIT to discuss this in details and he is quite excited about our work. However, the journey is still too long, and we can use flying robots to enhance this journey and avoid plenty of tests on humans’ said Pucci.
So far, they have got a basic control framework for controlling simulated iCub robot in a hover and gentle motion. It relies on simulated jet engine thrust. Aerodynamic effects and minor practical issues are not taken into account.
QP (quadratic programming) solver is applied to deal with actuation limits. The robot joint torques, which stabilize the joint velocities (to get momentum control) are created through a high-gain control system at the joint level. Plenty of tests were done on iCub robots, and simulation results prove the soundness of this proposed method.
Reference: Momentum control of flying humanoid robot
Conclusion and Future
The research work has proposed extensions of vector thrust control technique used in vertical take off and landing (VTOL) control. The primary assumption is that four thrust forces are used to power the robot. These forces decrease but do not completely remove the human robot underactuation.
The paper has uncovered control laws providing stability as well as convergence properties for centroidal momentum of the robot. A little bit of modifications in these laws enables us to track robot’s center of mass trajectory and retain small tracking error between the robot base frame and a reference orientation.
In this way, future study proposing control laws doesn’t only guarantee convergence and stability of suitable center of mass location and angular momentum, but also frame’s reference orientation.
Moreover, external forces exerting on the robot neglect aerodynamic occurrence. Therefore, future work will also involve extension of vector thrust control technique with aerodynamic effects.