Cockroaches are often considered pests because they hardly provide any purpose, but they may soon find their purpose as scientists are now developing cooperative cockroaches.

Researchers from the University of California Berkeley Biomimetic Millisystems Lab previously developed the Velocity Robotic Autonomous Crawling Hexapod (VelociRoACH) to aid rescue operations because of their ability to squeeze through tight spaces of collapsed buildings. Researchers said that deployment of these robotic cockroaches in disaster areas would give rescuers valuable information, such as point of entry that would hasten rescue efforts.

While they are relatively affordable to produce because robots use Smart Composite Microstructures (SCM) process, their underactuated legs limit their versatility.

Study lead author Carlos Casarez, inspired by army ants' cooperative behavior to build structures, modified the VelociRoACH to assist each other as they overcome an obstacle by using small magnetic tether systems.

Casarez explained that when two VelociRoACHes coordinate their activity, they become a modular robot that has the ability to extend their conjoined body and maximize the use of their legs. Similarly, one robot can serve as an anchor as the other robot can use the system to assist in pulling.

The minimalistic design of the VelociRoACHes provides more versatility compared to other previous systems. Instead of having one robot climb up, the winch also serves as a tool to help pull the other robot up the stair as well. Although the robots only have a 10 percent success rate, Casarez explained that basic sensor feedback would address the problem. He said 10 percent is still a breakthrough because the VelociRoACHes are not equipped with any sensory feedback system yet that would control the segments of the behavior.

In the paper [PDF], researchers wrote that they are planning to include a closed-loop feedback control that would significantly enhance the cooperative step climbing behavior reliability. Sensory feedback control would include connection contact sensors, robot-to-robot localization, and IMU/motor torque information.

More Robots, More Actions?

Based on the cooperative behavior models of army ants, having more ants increases the complexity of structure that they can build. Will the same theory apply to VelociRoACHes?

Putting together robots using connection components and winch modules can overcome bigger obstacles. Terrain gaps could also be addressed, but Casarez pointed out that this could also limit the reliability of the behavior. Failure, even in one robot pair, could cause the entire operation to collapse.

"I think there is some more interesting work in exploring how far two-robot cooperation can go. For example, instead of climbing a step, the robot with the winch could be used as an anchor for a tethered VelociRoACH that explores down an unknown chasm, which can then be retrieved after exploring," said Casarez.

The team is also looking at interactions of VelociRoAChes with heterogeneous robot swarms.

The researchers will present their work at International Conference on Robotics and Automation 2016 in Sweden.

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