"ROCR alternatively grips the wall with one hand at a time and swings its tail, causing a center of gravity shift that raises its free hand, which then grips the climbing surface," the study says. "The hands swap gripping duties and ROCR swings its tail in the opposite direction."
ROCR is self-contained and autonomous, with a microcomputer, sensors and power electronics to execute desired tail motions to make it climb.
Provancher says that to achieve efficiency, ROCR mimics animals and machines.
"It pursues this goal of efficiency with a design that mimics efficient systems both in nature and manmade," he says. "It mimics a gibbon swinging through the trees and a grandfather clock's pendulum, both of which are extremely efficient."
The study says: "The core innovations of ROCR its energy-efficient climbing strategy and simple mechanical design arise from observing mass shifting in human climbers and brachiative [swinging] motion in animals."
Simulating and Testing a Climbing Robot
Before testing the robot itself, Provancher and colleagues used computer software to simulate ROCR's climbing, using such simulation to evaluate the most efficient climbing strategies and fine-tune the robot's physical features.
Then they conducted experiments, varying how fast and how far the robot's tail swung, to determine how to get the robot to climb most efficiently up an 8-foot-tall piece of plywood covered with a short-nap carpet.
The robot operated fastest and most efficiently when it ran near resonance near the robot's natural frequency similar to the way a grandfather clock's pendulum swings at its natural frequency. With its tail swinging more slowly, it climbed but not as quickly or efficiently.
The researchers found it achieve the greatest efficiency 20 percent when the tail swung back
|Contact: Lee Siegel|
University of Utah