Talk about a power user.
As an independent consultant who specializes in computer simulation of electro-mechanical products, Chuck Pitzer has put Pro/ENGINEER to use for years. He and his company, Pitzer Consulting, have worked with companies from Boeing and Intel to Raytheon and Volvo. They’ve helped design or improve everything from bulldozer blades to missile wings.
But pull him aside, and Pitzer likes to tell how Pro/ENGINEER, and specifically, its simulation solutions, has helped him with some off-the-wall, hobby-inducing projects.
Battling bots. For one thing, he likes to build BattleBots, those enormously intimidating machines that roll around fighting each other with blades, saws, punches, and just about every other weapon a 60-or-so-pound robot can muster. BattleBots are built to take a beating, and move fast – a 60-pound Bot might have a four horsepower motor. They operate by remote control, run by a human pilot who stands outside the arena. And each Bot typically has one weapon – it may be a whirling saw, a hammer, or even a titanium “lifter” for instance, that is employed to put its competitors out of business.
Pitzer has designed BattleBots that use each of these weapons – see his Team Raptor Web site for the lurid details. For his lightweight-class Alpha, Beta, and Gamma Raptors, he designed titanium “scoop spikes” as lifter weapons. The method is to hook the spikes under the enemy’s chassis, lift its wheels off the ground, and thus render it useless.
Pro/ENGINEER Structural and Thermal Simulation helps in a number of ways. During the original design, Pitzer uses it to determine how, and where, the machine should be strengthened or stiffened. Following a battle, he may use it to improve his Bot’s chances in the next encounter.
Gamma’s lifter. In one of Pitzer’s lightweight Bots, Gamma Raptor, his goal was to design a lifter that could lift twice the weight of its own Bot (lightweights are 60 pounds or under). That way, he could team up two Gamma Raptors to fight against a single middleweight machine.
“We use an electric actuator that drives the lifter up and down,” he says. “First, we figured out how much weight we wanted to lift, how much the actuator could actually push, and what height we wanted.
“Then I used motion optimization capabilities in Pro/ENGINEER to determine the best configuration for the lifter linkage. This can be tricky, because you’ve got another variable (packaging) to consider. It all has to fit into your Bot, and the components can get pretty crowded.”
A hole in the side. As for an example of a Bot in need of repair, Pitzer tells of a nasty encounter with Ziggo, a Bot that uses a whirling, cutting-edge disk as a weapon.
“He put Beta Raptor out of commission when the disc broke through our titanium side armor,” says Pitzer. “What was surprising was that there was just a one-inch hole in the side, but the thrust of the disk caused lots of internal damage, including a bent chassis and broken sprockets.”
Pitzer used Pro/ENGINEER Structural and Thermal Simulation to measure the total deformation by reverse-engineering the scenario.
“I determined the extent of the load that had hit the Bot, built a load case, and then used what-if scenarios to help with adding gussets and stiffening the chassis,” he says. A key benefit of using Pro/ENGINEER wasn’t so much the time saved over manual calculations, he says, but in the accuracy of the results.
“The key to winning is to do the most with the least weight, and Pro/ENGINEER helped me find just the right amount of re-design, without going too far,” he says.
An arena on wheels. Pitzer has also applied his lifting expertise to help build an entire arena – actually, a mobile arena – for fighting robots. The arena was to be built into its own truck, so its designers, Chuck and his brother, Bob, had to find a way to stow and deploy the 2,000-pound side floors that would unfold to create the full arena.
“We needed a very powerful lifting mechanism that would permit fast setup and takedown of the facility,” says Pitzer. He used the kinematics and structural analysis capabilities in Pro/ENGINEER to optimize the linkage configuration.
“I designed the basic linkage, and then used Pro/ENGINEER Motion Dynamics to run it under different load scenarios. I took the worst-case loads from the motion analysis and applied them to the structural analysis, and then fine-tuned my linkages based on that.”
“Change your tire?” Recently, Pitzer turned his attention to another type of lifting challenge: designing a human “exoskeleton” that will give its wearer Superman-like lifting strength.
“This will basically fit the lower half of the body,” he says. “And it will have an apparatus the wearer can use to lift tremendous weights.”
So far, he’s used Pro/ENGINEER —with its kinematics capabilities and behavioral modeling to optimize the lift paths for his hydraulic systems. The next challenge will be to teach the exoskeleton to walk. This will raise the design complexity to a new level, since walking requires an ability to balance – however briefly -- on one foot at a time.
He’ll do it, though, thanks to Pro/ENGINEER. And, he says, he’ll still have time for his day job.
Pitzer Consulting is based in El Segundo, CA, USA. They specialize in developing better products through simulation. Their software and service solutions have been helping engineers and manufacturers do their jobs with an unmatched level of excellence.
· Special limited time offer: Pro/ENGINEER and Structural and Thermal Simulation for $4,995 USD.
· Revenge of the Robots: An Interview with Chuck Pitzer (March 2001)