The iRobot Warrior, using a tool on the end of its arm, is able to grab, lift and carry heavy items. The arm can lift up to 350 pounds and the Warrior can carry a payload of up to 150 pounds. (Photo courtesy of iRobot.)
By Robert Karlsen and Bob Van Enkenvoort
A small car can’t pull a heavy trailer. Sports utility vehicles (SUVs) don’t have a compact car’s fuel efficiency. A perfect, one-size-fits-all vehicle doesn’t exist. The same goes for unmanned ground vehicles (UGVs).
Soldiers use UGVs— such as the 40-pound PackBot or the larger, 115-pound TALON — to detect and defeat roadside bombs, gain situational awareness, detect chemical and radiological agents, and increase the standoff distance between Soldiers and potentially dangerous situations. Just as SUVs offer utility smaller cars can’t match, larger UGVs provide capabilities not available with smaller platforms.
The 300-pound iRobot Warrior, developed in partnership with the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC), is a large UGV that offers more lifting and carrying power, as well as the potential for better dexterity to grab items or open and close doors. The Warrior’s capabilities combine that of a TARDEC-developed map-based navigation and those of the Warrior’s predecessor, the Neomover, which was larger than a PackBot and could perform several dexterous tasks with its robotic arm.
Warrior Holds Up in Exercises
The development team evaluated Warrior UGVs in several live exercises and a real-life disaster response. In February 2009, TARDEC brought the Warrior to the Cobra Gold tactical exercises in Thailand for an assessment at the Marine Experimentation Center.
“A group of Marines were part of the exercise and they tested the system’s mobility, communication-range capabilities, how well can it go up and down stairs and through corridors and hallways,” said Jeremy Gray, TARDEC Ground Vehicle Robotics (GVR) research electrical engineer.
At the exercise, the Warrior was tested with several infantry mission scenarios including: entry-point checkpoint, vehicle security, building clearance, cordon and search, route clearance, assess mobility and casualty extractions. The Cobra Gold evaluations were vital in helping TARDEC associates determine how to move forward with the platform’s development. “We learned that the systems needed some improvements before we could get them to a fieldable maturity level,” noted TARDEC GVR Customer Support Team Leader Lonnie Freiburger. “There were some good data points that showed that if we continued to make S&T investment in mission payloads — such as manipulators, platform intelligence, power, vision and explosive and chemical detection systems — we could have a better product.”
The iRobot 710 Warrior with APOBS provides warfighters with a powerful and rugged unmanned system that facilitates the deliberate breaching of anti-personnel minefields and multi-strand wire obstacles.
Shortly after that evaluation, TARDEC received Congressional funding to work with iRobot in the development of two Warrior manipulator arms in July 2009. The arms were required to weigh less than 45 kilograms (kg), have a reach of 1.5 meters, lift a 50 kg object and move it 50 meters, drag a 100 kg object for 50 meters, dig 25 cm into the soil, and turn over a 50 cm x 50 cm x 4 cm piece of concrete. iRobot eventually doubled the lift capacity and extended the reach to 1.9 meters, increasing the weight to 54 kg.
iRobot also developed a mechanism attaching an Anti-Personnel Obstacle Breaching System (APOBS) to the Warrior to tele-operate it into position and remotely fire the munition. The APOBS has two boxes with a line charge with grenades attached at intervals. An attached rocket is shot to lay out the line. The grenades on the line then detonate and clear a path for users.
The APOBS is a fielded system, but must currently be put in place manually. Because of that, adding it to the Warrior or other tele-operated UGVs meant having to start from scratch.
“Trying to take a system that was designed for that and adapt it and integrate it to a UGV was a great challenge because the technical reports and training manuals don’t have helpful information,” noted Gray. “We had a lot of questions [regarding the APOBS integration] and asked the developers that made the training manuals and they weren’t even sure. So it was a lot of: ‘Let’s see if this works.’ Luckily, we got through it all without blowing up the robot. It ended up being a success. We had a couple of close calls, but we learned a lot from that.”
After those refinements were made, the team put Warrior to the test again. The Congressional funding also allowed them to run more drills at the Navy’s China Lake, CA, facility in November 2009, and then twice at the Combined Arms Live Fire Exercise (CALFEX) during 2010 Cobra Gold, outside of Chai Badan, Thailand.
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“It is a really big show. That’s when you have air and ground forces coming together from different countries. … It’s basically one big exercise of one big assault. So you had air strikes and mortar rounds coming into an area,” Gray commented. “The ground forces used the APOBS for the initial penetration, so the Warrior went up to the concertina wire, launched and blew that out of the way and then the ground forces were able to go in and complete the exercise.”
Currently, one of TARDEC’s Warriors is undergoing final software testing. The other is at Re2’s facility supporting two SBIRs that TARDEC manages on semi-autonomous door opening and enhanced manipulation feedback. They are also being used to support Gray’s innovation project in developing a new gripper design.
“Re2 is developing an enhanced intuitive control,” Gray noted “A lot of the manipulators don’t have real fine movement, and they don’t have haptic feedback, which is a type of feedback that goes back to the users so they have an idea of what is going on.”
In that light, Re2 is building an end-effector tool kit for the Warrior arm with automatic tool- change capabilities. “On the end of your arm, there is some sort of tool — whether it’s a gripper, whether it’s a knife — that they have the ability to change out automatically.”
In marsupial mode, the iRobot 710 Warrior carries a PackBot to approach, investigate and neutralize IEDs while keeping personnel at a safe standoff distance.
An assessment using the Warrior manipulator arm and the Re2 Modular Intelligent Manipulation and Intuitive Control (MIMIC) was completed in December 2011 at Camp Pendleton, CA. Scenarios involved opening doors, getting through locked doors and finding a locked device. The tasks were also done with smaller UGVs without the tool-change capabilities.
Engineers took a unique approach to gather information in terms of what tools to design for the system. “We went out to Fallujah, Iraq, when we deployed and took photos of all the tools being strapped onto the robots. This is the ad-hoc stuff that the user is putting on,” Freiburger added.
It makes sense to have conformed hardware designs instead of the makeshift tools added in the field. “It sounds like there is an opportunity to leverage what industry is doing, but industry is a little different. They’re more focused on very precise tasks in a benign environment. We’re dealing with very complex environments. Our tolerances are a little more open than what they have to deal with.” Tools currently being designed include:
- End effectors – grippers – for different style of doors.
- Engineering tools for route clearance, diggers and trenchers.
- Small pneumatic sledgehammers that can pick through the ground.
- Wire rakes to pull command wire from the ground.
- Window breakers to do entry control point type of jobs.
Real-life Disaster Testing
In addition to the California and Thailand exercises, iRobot sent two PackBots and two Warriors to Japan after the March 2011 magnitude 9.0 earthquake and tsunami that left around 19,000 people dead or missing and damaged several nuclear reactors to the point of near failure.
The PackBots were first sent into a reactor to gain situational awareness, where the investigation found radiation levels of 72.0 Sieverts inside the reactor’s containment vessel — enough to kill a person in minutes.
Tim Trainer, interim general manager of iRobot’s Military Business Unit, said the UGVs stood up well to the conditions. “We knew going into the operation that Warrior was a very rugged platform, but we didn't know how much of an effect the high radiation levels would have on the robot operationally. We're pleased that Warrior has continued to perform unaffected in this environment.”
Workers also outfitted the platform with an industrial vacuum cleaner to remove radioactive debris and further reduce radiation levels.
The Right Machine for the Job
Moving ahead, the challenge is building the right size robot for the job. “There isn’t a perfect robot,” Gray noted. “Eventually, you’re going to have an arsenal of robots, and you’re going to pick the one that’s going to help your mission the best each day.”
Today, Soldiers primarily tele-operate robots. “There are some intelligent features that vendors are selling such as scripts for movements, such as manipulation. Maybe you need to reposition an arm before it can go upstairs. You push a button and the center of gravity is recalibrated from the manipulator for all the payloads and now you can climb up the stairs. Maybe you have a user that is continually picking up objects so now you have a script for that task,” Freiburger added. “We know we want to reduce the cognitive load of our warfighters and eventually be a force multiplier.”
For now, engineers are working on augmented tele-operation to improve the op-tempo in any way possible, and continue the quest for improved autonomy and dexterity. “A robot is an enabler,” Freiburger said. “We’re constantly working on improving the touch, senses, and other ways of communicating and understanding our environment. [We’re] trying to make the robots more like humans in any way possible.”
The 300-pound, 35-inch-long and 29- to 32.5-inch-wide (depending on the model) iRobot Warrior was built to be durable and have myriad capabilities. The Warrior:
- Operates in all weather conditions
- Can haul a payload of 150 pounds and lift up to 350 pounds
- Features a dual-track system with articulated flippers for enhanced mobility
- Has extreme mobility in aggressive terrain and urban environments
- Can be used for indoor or outdoor missions
- Runs on battery power that lasts 2-16 hours depending on mission profile
- Needs only one minute for battery trade-out
- Can handle a multitude of functions including: Explosive ordnance disposal, vehicle-borne improvised explosive devices, SWAT, reconnaissance, hazardous materials, chemical and biological weapon detection, battlefield casualty extraction, physical security, firefighting, surveillance, target acquisition and weaponized missions.
Robert Karlsen is a research physicist with TARDEC’s Ground Vehicle Robotics. He began working at TARDEC in 1994 for the Survivability Technology Area and moved to Ground Vehicle Robotics in 2003. He earned a bachelor's degree in physics from the University of Washington in 1986 and a doctorate in physics from the University of Arizona in 1993. He is a member of IEEE and SPIE.
Bob Van Enkenvoort, Alion Science & Technology, provides technical writing support to TARDEC's Chief Scientist's Office. He holds a B.A. in journalism from the University of Wisconsin-Whitewater, and brings 20-plus years of editorial experience managing newspapers and magazines in Wisconsin, Minnesota, Michigan and Iowa.
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