WASHINGTON — Like the four horsemen of the apocalypse, war, terrorism, crime and disaster are driving the development and deployment of fresh armies of robots.

Equipped with "eyes," "ears" and "noses," improved mobility and manual dexterity plus rudimentary "intelligence," many newfangled machines are being tested for use in military situations and civilian catastrophes.

Their sponsors hope they can get over the serious problems and weaknesses that have limited their usefulness in the past.

In Afghanistan, for example, Taliban fighters have developed ways to foil robots that were trying to search caves by using ladders and flipping them onto their sides. Last week, however, robot makers showed off a robot that could climb a steeply slanted roof without falling off.

It was one of a pack of machines that demonstrated their prowess at a demonstration sponsored by the National Institute of Standards and Technology in Gaithersburg, Md.

Unfortunately, even the newest gadgets sometimes didn't work as well as their makers or their users had hoped.

During one demonstration, eight out of 16 robots failed a simple test. They were supposed to drive to a set of checkpoints, but their radios interfered with one another's signals so badly that they couldn't communicate with their controllers.

"It was difficult even to get from the start point to the first building," said Kate Remley, a NIST researcher. "This would be a serious problem in a real situation."

In Iraq, robots have had mixed success. They're useful in detecting hidden explosives, but they frequently get stuck, fall over or fail to distinguish between humans and animals.

"Some maps made by robots have so many errors they are useless," said Steve Balakirsky, an electronics engineer at NIST.

Adam Jacoff, an urban search-and-rescue expert at NIST, said mobile robots had difficulty with such things as curbs, manhole covers, high grass and light poles.

"Dangling wires, plastic bags, dust can bring a robot to a screeching halt," Jacoff said. "Obstacles come up everywhere."

Experts at the Gaithersburg demonstration conceded that humans — even dogs — usually can do better than machines in search-and-rescue missions.

Dave Lesh, the leader of a Federal Emergency Management Agency "first responder" team from Riverside, Calif., said, "Dogs were our most valuable asset" in the hunt for victims of Hurricane Katrina last year.

Nevertheless, Lesh said he was encouraged by some of the new robot skills demonstrated in Gaithersburg.

"I've seen stuff here I never thought would be possible," Lesh said after watching the machines perform their repertory of tricks.

Snakelike robots with cameras on their heads wriggled into tiny spaces where a person couldn't fit. Robots rolling on miniature tank tracks climbed stairs and flipped onto their backs to scramble over obstacles. A diminutive helicopter buzzed overhead, sending back pictures of the scene below. A power mower-sized robot popped the hood, opened the trunk and yanked the door off a car that could have concealed a bomb.

"They're saving lives in Iraq right now," said Charles Shoemaker, a veteran robot expert who recently retired from the Army Research Laboratory in Adelphi, Md.

"They would have been a big help in New Orleans," said Mark Hundley, a hazardous-materials specialist from Virginia Beach, Va., who worked with a FEMA team after Hurricane Katrina.

Elena Messina, a senior engineer in NIST's Intelligent Systems Division, said, "Events in the past few years have stimulated interest in the application of unmanned systems." For example, she said, "Unmanned aerial vehicles developed by the military are starting to be used in border security and other civilian domains."