May 2, 2006 Safeguarding the soldier is the key aim of the Unmanned Ground Combat Vehicle – giving soldiers enhanced stand-off capability was the reason DARPA funded the Grand Challenge and backed up again two years later with the second challenge and is now holding the challenge in an urban area – such contests dramatically accelerated research into autonomous navigation and identified the most capable people to for the military to work with. The National Robotics Engineering Center (NREC) is part of the Robotics Institute in Carnegie Mellon University's School of Computer Science, unveiled Crusher last week. Carnegie Mellon vehicles finished a close second and third in the Grand Challenge though everyone knew they were at the bleeding edge of robotics knowledge, the Challenge just confirming it. Crusher demonstrates just what we can expect to see on the battlefield a decade from now. In what might well be seen as an offspring of the Grand Challenge, “Crusher” is a new breed of UGV – an NREC-designed, six-wheeled, all-wheel drive, hybrid electric, skid-steered, unmanned ground vehicle. The bohemoth weighs 14,000 pounds fully fueled, and is designed to carry a 3,000-pound payload – at this 17,000 pound total weight, two Crusher vehicles can be carried by a single C-130H aircraft and dropped into any region in the world. Once on the ground, Crusher can carry up to 8,000 pounds of payload without compromising its mobility – read that as 8000 pounds of smart stuff – any combination of cargo, armour, armaments, or surveillance equipment. Crusher is also designed to withstand extreme terrain, with the ability to take in its stride regular impacts with trees, boulders, fences, tree stumps and ditches at high speed. With six wheel independent drive, Crusher can go up and over almost anything, and if in the process it should get upside down, it moves its wheels to the other side of the vehicle and starts all over again. Crusher's hybrid electric system is silent, using a high-performance SAFT-built lithium ion battery module which delivers power to the six, in-wheel UQM traction motors located in the hub drive system of each wheel. Much, much, more … interesting stuff!
The suspension is designed by Timoney offering a remarkable 30 inches of travel with reconfigurable ride stiffness and ride height.
Crusher and its predecessor, Spinner, demonstrate the realm of the possible with regard to a combination of autonomous behaviors, hybrid electric propulsion and robust vehicle design so we should start the story with reference to Crusher’s dad, Spinner.
Spinner was designed to take maximal advantage of the uncrewed UGCV aspect. Whereas the DARPA challenge was all about working out how to replace the capabilities of a human being (navigation/driving), and contestants chose conventional proven vehicles designed to incorporate a driver, Spinner could use the entire internal space with complete design freedom.
The most obvious manifestation of this in Spinner’s design was its ability to invert itself. Humans aren’t comfortable upside down but a purpose built machine doesn’t mind at all. Ingeniously, this overcomes the problem of the vehicle being capsized and immobilised. With wheels transferable to the other side of the carriage, the Crusher and its direct forebear, Spinner, can drive out of anywhere.
The advantages of removing the driver go well beyond the inversion though, as the large central, payload bay rotates to position payloads upright or downward. In addition to rollover crash survivability, the hull, suspension and wheels were designed for extreme frontal impacts such as striking a tree, rock or unseen ditch at high speed.
With a brief of being able to cover extreme terrain, and with navigation still in its infancy, Unmanned Ground Vehicles must be able to surmount terrain obstacles, as well as survive and recover from impacts with obstacles and unpredictable terrain. They must also be fuel efficient and highly reliable so that they can conduct long missions with minimal logistical support.
Resilience was imperative – manned vehicles have people to fix them when things go wrong, whereas unmanned vehicles do not. An unmanned ground vehicle must have the ability to withstand considerable abuse during a mission and still get the job done. Such abuse is common to unmanned vehicles that are controlled by distant teleoperators or by semi-autonomous sensors and software.
To focus prototype development, DARPA established primary design metrics: • Obstacle capability (1m+ positive, 2m negative, 35 slopes) • Resilience (withstand abusive use while remaining lightweight) • Endurance (14-day missions; 450 km range without refuelling) • Payload Fraction (more than 25% of gross vehicle weight)
Spinner’s demonstrated performance during two years of intense testing in extremely rugged terrain exceeded these metrics.
As prime contractor, NREC managed the performance of over 30 trade studies, risk reduction activities, subsystem design and test activities. NREC also led all integration and assembly operations, and executed all performance testing. Additionally, NREC was responsible for many subsystems, including thermal management, prime power, ride height control, braking, safety, command station, OCU, communications, and teleoperation. Moreover, NREC developed all the vehicle positioning, automation, data gathering and data analysis systems that were used on a continuous basis to test the vehicle.
Following design, fabrication and assembly, Spinner completed two years of intense testing to assess its capability in a variety of terrains, weather conditions, and operational scenarios. For example, during a government-controlled field test at the Yuma, Arizona Proving Grounds, Spinner covered nearly 100 miles of very rough off-road terrain.
The 6.5-ton Crusher combines Spinner's strength and mobility with NREC-developed autonomy capabilities to create an extremely robust unmanned ground combat vehicle that can operate in complex terrain.
Crusher and Spinner feature technologies that are six to 10 years ahead of their time and give an unprecedented glimpse into the future capabilities of unmanned military vehicles. Crusher will undergo extensive field tests for the next two years. The platform is expected to influence future unmanned vehicle design efforts funded by the Army's Future Combat System.
Crusher has a new space frame hull designed by CTC Technologies and made from high-strength aluminum tubes and titanium nodes. A suspended and shock-mounted skid plate made from high-strength steel allows Crusher to shrug off massive, below-hull strikes from boulders and tree stumps.
The nose was completely redesigned for Crusher to sustain normal impacts with trees and brush while also absorbing the impact of major collisions.
As a core building block in the Army's future force, tactical UGVs enable new war-fighting capabilities while putting fewer soldiers in harm's way. The full benefit of this new capability can only be achieved with field-validated understanding of UGV technology limits and consideration of the impact to Army doctrine, personnel, platforms and infrastructure.
UPI experiments encompass vehicle safety, the effects of limited communications bandwidth and GPS infrastructure on vehicle performance, and how vehicles and their payloads can be effectively operated and supervised.
By mid 2006, NREC will integrate its latest automation technology onto both Crusher vehicles. A combination of ladar and camera systems allow the vehicles to dynamically react to obstacles and travel through mission waypoints spaced over a kilometer apart.
The use of overhead data via terrain data analysis will continue to be utilized for global planning. Over the next year these two vehicles will analyze, plan, and execute mobility missions over extreme terrains without any human interaction at all. Crusher’s suspension system allows it to maintain high offroad speeds across extreme terrains
DARPA created the Unmanned Ground Combat Vehicle (UGCV) program to develop vehicle prototypes based on novel designs unrestrained by the need to accommodate human crews. The resulting prototypes demonstrate advanced configurations and technology that are applicable to UGV design programs for the US Army’s Future Combat System (FCS).
NREC with its three first level subcontractors (Boeing, Timoney Technology and DRS-TEM) developed and tested Spinner, a highly durable, invertible, six-wheel-drive, hybrid-powered vehicle that responds to the need of a UGCV to surmount challenging terrain obstacles, be easily teleoperated, and able to withstand an occasional moderate crash and rapidly recover.
Crusher is being equipped with state-of-the-art perception capabilities, and will be used to validate the key technologies necessary for an unmanned ground vehicle to perform military missions autonomously. Crusher will be equipped with representative sensing and weapons payloads for planned field experiments. DARPA Director Tony Tether noted, “With the combination of a robust, highly mobile vehicle design and an innovative autonomous control system, Crusher defines the state-of-the-art in autonomous unmanned ground vehicles systems. DARPA is pleased to be working with the Army to bring this new capability to fruition.”
“The Future Combat Systems (Brigade Combat Team) program has been working with DARPA’s UPI program for some time now, leveraging their advancements in robotics field testing, perception algorithm development, autonomy, and, more recently, in understanding wheeled system design characteristics for mobility and remote control latency and bandwidth effects on mobility performance,” explained Maj. Gen. Charles Cartwright, Program Manager Future Combat Systems (Brigade Combat Team).
“The FCS (BCT), Lead Systems Integrator, and platform providers have all witnessed and participated in dialog with DARPA and Carnegie Mellon University’s National Robotics Engineering Center related to Spinner and now Crusher experimentation. This interaction has been of great benefit to the FCS program, and we look forward to continued interaction and transition of technologies from this new vehicle system to our FCS UGV systems.” “The two new Crusher vehicles are a major improvement in unmanned ground vehicle capability,” added Larry Jackel, DARPA UPI program manager. “The original Spinner UGCV is an excellent platform, but in shakeout experiments, the new Crushers have already outperformed Spinner in all aspects. Combined with its autonomous control system, the Crusher defines the state-of-the-art in autonomous unmanned ground vehicles systems.” The UPI program will conduct rigorous field experiments of the two Crusher vehicles and their perception and payload systems, with experiments planned at Fort Carson, Colo., this summer. The program will culminate in 2007 with Army users operating Crusher vehicles during representative missions in natural terrain. The UPI effort will merge all Crusher functions (mission planning, perception monitoring, vehicle monitoring, and payload operation) into an operator workstation interface and determine interaction requirements via experimentation.