Two VelociRoACH Robots Cooperatively Climb a Step Taller than Their Size

Two VelociRoACH Robots Cooperatively Climb a Step Taller than Their Size

May 6, 2016 @ 20:49 |

Researchers at Biomimetic Millisystems Lab, University of California, Berkeley, have taken inspiration from the cockroach and created a Cockroach-Inspired Robot VelociRoACH (Velocity Robotic Autonomous Crawling Hexapod) and demonstrated that two VelociRoACH robots cooperatively can climb a Step. Researchers will be presenting their research work “Step Climbing Cooperation Primitives for Legged Robots with a Reversible Connection” in IEEE ICRA conference 2016.

In this research paper, researchers demonstrated that physical cooperation between robots (VelociRoACH) can enable mobility over tall obstacles relative to their size.

Small bio-inspired robots have the potential to improve the effectiveness of robot-assisted search and rescue in disaster scenarios (e.g. collapsed buildings). Small-scale robots can navigate through narrow spaces in a collapsed building that would be otherwise inaccessible. Furthermore, these robots can be produced cheaply and quickly. Deploying many capable and low-cost robots throughout the disaster area will help to accelerating the discovery and rescue of survivors. While underactuated, bio-inspired legged robots have demonstrated high-speed running performance (A Legged Robot Running Beyond the Bio- inspired Methods) on level ground with some obstacles (Cockroach-Inspired Robot uses Body Shape to Negotiate Densely Cluttered Terrain).

But climbing over step obstacles that are larger than the robot’s length scale poses a great challenge for an individual robot. To solve this problem, UCB researchers tried multi-robot physical cooperation such as Australian jumping ants, which are shown cooperatively traversing complex terrain in the attached video.

(This video demonstrates step climbing cooperation primitives that enable a team of two VelociRoACH robots to climb a taller step than they could individually. The addition of a winch module that exerts tensile forces on a tethered magnetic connector allows the robots to form connections, provide tether pulling assistance, and remove connections. Successful trials for (I) single robot transition, (II) form connection, (III) connected climbing, (IV) release connection, and (V) tether-assisted climbing primitives are shown. When these independent primitives are performed sequentially, the robot team can climb a high-traction sandpaper step 6.5 cm in height, which is tall relative to their 10 cm body length.)

The proposed two-robot team for cooperatively climbing step obstacles is shown in video. The base robot platform is VelociRoACH, a 47 g, 10 cm long bio-inspired legged robot. On each side of the robot, a brushed DC motor with a 64:1 reduction spur gear transmission drives an SCM kinematic linkage made of PET and Nylon.
VelociRoACHThe back robot is outfitted with a rapidly-prototyped winch module, which is used to tension the tether between the two robots. The winch tether is attached to a magnetic connector, which can be retained by the back robot (Fig.a). When the magnetic connector joins the robots together with a compliant pin connection (Fig.b)

Limitations of experimental system:

  • In forming the connection, alignment of the two robots is important for success, so detection of relative heading and distance of the robots is important.
  • The front robot should always find an anchoring point to support the back robot’s tether pulling loads (primitive V).


 

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