It’s one of those things about walking upright. Sometimes two legs are not enough for this, especially if the ground is uneven. Then it is good to be able to hold on to the banister or to be able to support yourself on the wall. That sounds simple and obvious, but it isn’t – at least not for a humanoid robot.
Better arms for robots
So the robot needed LOLAwhich has been developed at the Technical University of Munich since 2004 Upgrade for his upper body. So far, the arms have primarily served to compensate for fluctuations that occurred when walking quickly, explained Philipp Seiwald at the conference Humanoids. In order to be able to use it for support, it was necessary to implement a further degree of freedom in the form of a rotating upper arm. As a result, the volume that can be reached by the tips of the arms (LOLA does not have hands yet) has been increased from 0.286 to 1.303 cubic meters. It also showed that the stiffness of the back and shoulders was insufficient, which would have required a completely redesigned torso.
The new upper body, in turn, needs new software to control it. From the data from the RGB-D camera and the inertial sensors, it first calculates a model of the environment and the orientation of the robot in it. From this, she derives appropriate running behavior, which in turn is stabilized by its own software module. The software architecture is fully developed, said Seiwald. The individual algorithms are still being worked on. Both first experiments the support on the walls was therefore still programmed by hand. However, the robot is quite capable of compensating for deviations in the range of a few centimeters itself.
No holding on to the railing
Hold on to the banister, in case your balance becomes very critical, LOLA couldn’t yet. The spherical stumps at the ends of the arms are not suitable for this. But that is also being worked on. Another research team at the Technical University of Munich is developing a wrist whose two degrees of freedom are controlled by just three tendons – which is the theoretical optimum, as Alexander Toedtheide explained. A developed by the company Shadow, similar wrist work with four tendons. According to Toedtheide, one advantage of using tendons instead of motorized gears is the flexibility and adaptability of the joint, which is easier to achieve.
The wrist is used to align the hand, which can then perform an impressive variety of movements with its five fingers. A research team led by Thomas Feix (Yale University) tried to get this diversity under control five years ago, and one Taxonomy of 33 basic grips suggested. Li Tian (Nanyang Technological University) was referring to this at the Humanoids Conference and presented an artificial hand based on taxonomy. In Video recordings you can see how this hand accomplishes little tricks like turning a pencil or fiddling with chopsticks. Because it is manufactured using 3D printing, it costs less than common robotic hands, but it also has less strength and is not as robust. With one grip on the banister, LOLA couldn’t prevent a fall with this hand. But the research projects presented at Humanoids feed the expectation that humanoid robots will soon not only be able to walk on two legs, but will also be able to use arms and hands specifically for help.