That's one of the best articles I've seen on this event.
I run one of the Grand Challenge teams,
Team Overbot.
We have a vehicle (a modified six wheel drive Polaris Ranger), a shop in Redwood City, funding,
equipment, and people. We're well along; the vehicle has most of its actuators and some of the sensors working, and about a third of the software is running. We're one of the five DARPA-accepted teams.
Many of us are Stanford alumni or students, but this is not a Stanford project.
We need three more good programmers in Silicon Valley. "No pay, some risk, a fraction of the prize." If you're interested, we want to see 1000 lines of C++ you're proud of. You'll need to put in at least 250 hours between now and March. Click here to join.
Our basic technical approach is to build a rugged, reliable vehicle with conservative control strategies. Others may be faster, but we expect they'll get into trouble at high speed. Our top speed is 40MPH. The real problem with the Grand Challenge is not going fast on the easy parts; it's getting through the hard parts.
The 6WD chassis we're using is one of the most bump-tolerant platforms around. It can go over railroad ties at top speed without problems and
without going airborne. The center of gravity is low. The front and mid axles have independent suspension; the rear axle is a swing arm. This simplifies low-level vehicle control. All wheels can be driven, although at higher speeds, we will switch from 6WD to 4WD.
We have five computers on board. Three are small PC/104 machines, and two are Pentium 4 machines.
All run QNX (the OS for when it has to work.) All are industrial-strength ruggedized units. The actuators are all servomotors driven by industrial microcontrollers. All this hardware is off-the-shelf industrial control gear.
Sensors include LIDAR, doppler RADAR, sonars, cameras, INS, GPS, etc. Some of them are used in unusual ways. That's all I'll say about that.
The pathfinding strategy is indeed borrowed from video game technology. It's more structured than Brooks-type behavior based robotics, and it's less structured than Latoumbe-type planning. There are three layers of control; the top one we call the "back seat driver", because it has only advisory authority over the "driver".
We have road map and topo data onboard, but it's used more as a hint than as rigid guidance. We take the waypoints DARPA gives us (on a CD, at 0430 hrs the
morning of the race) and load it in. There's no offline preplanning. Wouldn't help in the real world.
If nobody wins this year, which is quite likely, we'll be back next year with a faster vehicle.
Actually, the main reasons electric cars are not more popular are:
1) Lengthy refuelling time 2) Limited cruising range 3) Cost is not competitive - either the vehicle is prohibitively expensive (as in this case) or the batteries need to be replaced after a relatively small number of charge cycles, and the cost of electricity to charge the vehicle is not competitive with gasoline or diesel.
Solve all of these problems at the same time, and you will be wealthier than Billy G. (And less resented for your wealth) I won't hold my breath though, barring some revolution in battery technology, I put my best hopes for an alternative energy vehicle in fuel cells.
It has long been possible to get good acceleration out of an electric car, I remember a 1970's popular science article describing an electric vehicle with regular lead acid batteries that used an energy storage flywheel that recovered braking energy and fed it back into the transmission when you hit the accelerator for quick takeoffs. While you were idling at a stoplight, the battery would gradually be topping up the flywheel velocity, ready for a jackrabbit getaway on the green light.
Slashdot Mirror
I run one of the Grand Challenge teams, Team Overbot. We have a vehicle (a modified six wheel drive Polaris Ranger), a shop in Redwood City, funding, equipment, and people. We're well along; the vehicle has most of its actuators and some of the sensors working, and about a third of the software is running. We're one of the five DARPA-accepted teams.
Many of us are Stanford alumni or students, but this is not a Stanford project.
Our basic technical approach is to build a rugged, reliable vehicle with conservative control strategies. Others may be faster, but we expect they'll get into trouble at high speed. Our top speed is 40MPH. The real problem with the Grand Challenge is not going fast on the easy parts; it's getting through the hard parts.
The 6WD chassis we're using is one of the most bump-tolerant platforms around. It can go over railroad ties at top speed without problems and without going airborne. The center of gravity is low. The front and mid axles have independent suspension; the rear axle is a swing arm. This simplifies low-level vehicle control. All wheels can be driven, although at higher speeds, we will switch from 6WD to 4WD.
We have five computers on board. Three are small PC/104 machines, and two are Pentium 4 machines. All run QNX (the OS for when it has to work.) All are industrial-strength ruggedized units. The actuators are all servomotors driven by industrial microcontrollers. All this hardware is off-the-shelf industrial control gear.
Sensors include LIDAR, doppler RADAR, sonars, cameras, INS, GPS, etc. Some of them are used in unusual ways. That's all I'll say about that.
The pathfinding strategy is indeed borrowed from video game technology. It's more structured than Brooks-type behavior based robotics, and it's less structured than Latoumbe-type planning. There are three layers of control; the top one we call the "back seat driver", because it has only advisory authority over the "driver".
We have road map and topo data onboard, but it's used more as a hint than as rigid guidance. We take the waypoints DARPA gives us (on a CD, at 0430 hrs the morning of the race) and load it in. There's no offline preplanning. Wouldn't help in the real world.
If nobody wins this year, which is quite likely, we'll be back next year with a faster vehicle.
Post questions and I'll answer them here.
John Nagle
Team Overbot
Actually, the main reasons electric cars are not more popular are:
1) Lengthy refuelling time
2) Limited cruising range
3) Cost is not competitive - either the vehicle is prohibitively expensive (as in this case) or the batteries need to be replaced after a relatively small number of charge cycles, and the cost of electricity to charge the vehicle is not competitive with gasoline or diesel.
Solve all of these problems at the same time, and you will be wealthier than Billy G. (And less resented for your wealth) I won't hold my breath though, barring some revolution in battery technology, I put my best hopes for an alternative energy vehicle in fuel cells.
It has long been possible to get good acceleration out of an electric car, I remember a 1970's popular science article describing an electric vehicle with regular lead acid batteries that used an energy storage flywheel that recovered braking energy and fed it back into the transmission when you hit the accelerator for quick takeoffs. While you were idling at a stoplight, the battery would gradually be topping up the flywheel velocity, ready for a jackrabbit getaway on the green light.