 |
 |
 |
 |
| |
|||||
|
|
|
|
|
||||
Increasing Mission Footprint through Robot Pairs By Bob Grabowski Unmanned systems are proving themselves to be effective replacements for humans in performing tasks that are dull, dirty, or dangerous. Such tasks range from the mundane, like border patrol and sentry, to the more hazardous, such as forward scouting and ordinance disposal. A robot does not get tired or lose focus. However, a single robot type cannot fulfill every need. Current robots tend to be designed for specific tasks and perform poorly at anything else. Like an army of specialists, robot teams of the future will be composed of different types of robots, each selected for its particular specialty.
Robots are inherently limited by their size. Large robots tend to be well-equipped, can carry large payloads, and travel great distances. However, they are limited by the terrain they can navigate. While some unmanned vehicles can travel off-road, they all have difficulties when moving in cluttered environments such as side streets or alleys. Small ground robots are more maneuverable, can access smaller spaces, and are less expensive to produce. However, their size can also be a liability. These smaller robots do not have the power, range, and speed for long distance operations and tend to be more restrictive in the payloads they can support. Moreover, their lower profile limits their ability to see. One way to quickly overcome the limitations of a single robot type is to look for ways to combine robots so that each compensates for the other's weakness. The idea is to pair the power and distance strengths of the larger robots with the maneuverability of their smaller cousins. MITRE has researched multiple robot designs for several years (see "Securing the Building with Multi-Robot Teams"). The MITRE Team To demonstrate the effectiveness of pairing different robot types, MITRE is combining the capabilities of two radically different platforms—the PackBot and the Meteor. The PackBot, designed by the company iRobot, is a rugged, tracked platform about the size of a small suitcase, designed to support military forces operating in harsh environments. Two articulated flippers, mounted at the end of each tread, can be operated independently, allowing the PackBot to grip and climb obstacles higher than its own body. Recessed in the center of its body is a head assembly that houses a field-hardened computer and sensor suite, including three cameras, an inertial navigation system, and a small global positioning system unit. The head assembly is mounted to the end of a retractable boom that can be extended above the robot to increase its sensing profile or retracted into the body well for protection. When extended, the head can rotate, pan, and tilt, giving the PackBot the ability to look around completely without moving its body. The PackBot is already being used extensively overseas in both Iraq and Afghanistan. It is designed to operate in some of the harshest environments and conditions. It can survive a fall of two stories onto a cement floor with no damage. It can run in a wide variety of terrain including hard road surfaces, packed earth, sand, and even high grass. It can climb stairs and maneuver through rubble. Its low profile allows it to easily navigate under parked cars and into tight spaces, making it ideal for inspection and reconnaissance. Its counterpart is the Meteor, a retrofitted Ford Sport Trac originally designed to compete in the 2005 DARPA Grand Challenge (see "MITRE Participation in the DARPA Grand Challenge"). This larger vehicle is capable of autonomously following a designated route, adjusting to road terrain while dynamically avoiding obstacles. A retractable ramp assembly mounted on the back of the vehicle allows it to deploy and recover the PackBot (or other smaller robots). Individually, each robot is competent at the range of tasks for which it was designed. Together, they complement each other's strengths to accomplish a broader range of missions. The IED Problem One mission that is particularly dangerous for humans is the handling and disposal of improvised explosive devices (IEDs). These are often hidden or buried alongside roads and designed to detonate when vehicles or troops pass by. In addition to their explosive hazard, IEDs are also being used to lure "first responders" into an ambush. Secondary IEDs are often buried or hidden in close proximity to the first. Terrorists frequently monitor these operations and quickly learn our patterns and limitations. Robots are already being used to disarm IEDs. For example, a robot can be armed with a small charge or disruptor. The remote operator then maneuvers the robot to within a few centimeters of the suspected IED. Through video feedback, the operator can place the small charge or discharge the disruptor. This role for the PackBot has proven to be highly effective and is being used extensively in both Iraq and Afghanistan. However, it has some drawbacks. First, the range of the robot is limited by how far it can communicate—typically on the order of 100 meters. Second, the operator must navigate the robot either by visual sighting or through feedback from the robot's video cameras. In addition to video signal latency, the operator is handicapped by the perspective of the small robot. The world looks radically different from only a few inches off the ground. The operator's view can easily be occluded by simple clutter like grass and rocks.
A Robot Pairs Approach The mission scenario for our robot pair is simple: An IED is identified and needs to be handled. The Meteor is deployed with a PackBot in its rear bay. The commander designates the route to the IED through a graphical overlay. The Meteor follows the designated route while making any necessary corrections based on terrain and road hazards. During transit, the Meteor relays its position and status as well as a live video feed of the area around it. Under normal operation, the Meteor travels autonomously to its destination. However, if the Meteor finds itself stuck or confused, it defers control back to the user, who can operate the vehicle remotely. Once the Meteor has reached its destination, it extends its ramp, and the PackBot drives out of the rear bay. Since the PackBot contains its own GPS unit, its route can be designated, similar to the way the Meteor operates. For tighter maneuvering, the operator can take control and, guided by the robot's main cameras, directly maneuver the PackBot. The PackBot makes its way over to the IED, places its charge, and retreats to a safe distance. Once the IED is disabled, the PackBot returns to the Meteor. As the PackBot comes within visual range of the Meteor, it is directed back on board. The Meteor and PackBot are now free to return to base or continue to their next mission. Field Testing In addition to several weeks of field testing in appropriate terrain
and conditions, we hope to have extensive interaction with the soldiers
that will actually use the robots. Warfare is an ever-changing landscape;
quite often a fielded system is not always used as it was originally intended.
The only way to adapt is through constant interaction and feedback. As
unmanned systems perform more and more missions once reserved for humans,
they will excel at them in the same way as humans have always done—through
teamwork. |
|
||||
| For more information, please contact Bob Grabowski using the employee directory. Page last updated: August 22, 2007 | Top of page |
|||||
Solutions That Make a Difference.® |
|
|
Robot
Synergy
Download this issue [1.1MB]