What bumping into the delicate structure?

The delicate structure should be the COTSbot itself and it should avoid rock-bumping.
What do you think?

Context:

A Starfish-Killing, Artificially Intelligent Robot Is Set to Patrol the Great Barrier Reef
Crown of thorns starfish are destroying the reef. Bots that wield poison could dampen the invasion
HOW IT WORKS 1. The COTSbot follows a preprogrammed path, moving up and down the Great Barrier Reef with the help of five thrusters. It stays close to the reef—and avoids bumping into the delicate structure—with the aid of sonar and multiple cameras. 2. The cameras scan for starfish, distinguished by their purplish colors, arm and thorn shapes, and creeping motion. Starfish often wrap around and hide under coral outcroppings, but the robot's software has been programmed to recognize those positions. 3. When the robot spots a crown-of-thorns starfish, its needle-capped pneumatic arm lowers and injects 10 milliliters of poisonous bile salts into the echinoderm. The compounds effectively digest the animal from the inside. 4. A poisoned starfish will die within 24 hours, leaving no opportunity for separation and regeneration—a survival tactic that is a boon for the starfish population but maddening to those trying to reduce its numbers. 5. The vehicle's tanks carry enough poison to kill more than 200 starfish in one four- to eight-hour mission. The rapid pace is key because even one starfish can spawn millions of young.
COURTESY OF QUEENSLAND UNIVERSITY OF TECHNOLOGY

More:
http://www.scientificamerican.com/article/a-starfish-killing-artificially-intelligent-robot-is-set-to-patrol-the-great-barrier-reef/