If Jonathan Tippett had his way, the Olympics of the future would showcase more than mere humans—he foresees human-powered robot athletes, too. And at a Toronto tech event this July, the Canadian mechanical engineer asked us to imagine racing events where pilots would embed themselves in massive exo-bionic mechs. Think of it as a pimped-out version of the dual-arm power loader Ripley donned in Extraterrestre or maybe the setups now familiar to Titanfall competitors.
We didn’t have to imagine for long. Tippett soon showed off the first entrant into this idea of mech racing, and the gasps made their way around the room quickly. Tippett had introduced us to Prosthesis, an electric-powered, 8,000-pound, 15-foot-tall exo-bionic platform that amplifies the motions of the pilot sitting within a cockpit in the middle of the mech. Built from chromoly steel, Prosthesis can potentially run at 21mph, jump as high as 10 feet, and operate for two hours on a single charge.
This qualifies as an impressive bit of manufacturing and engineering. But talking to Ars months later, Tippett says his mission is more philosophical than many think. “Prosthesis may be framed as a high-tech machine, but it’s an 8,000-pound metaphor on how tech has enabled us to do what we want and the important role humans still play in robotics.”
That ethos is why Tippett and his team at Furrion, an Indiana tech firm partnering with him on Prosthesis, opted to add a cockpit to the mech and make it a man-machine interface instead of the remote-operated bots we’ve seen in caged battles and drone racing leagues. “Prosthesis is an extension of the pilot’s body,” says Tippett. “It’s like riding a mountain bike, where immediacy is brought to your experience instead of you being a spectator.”
Currently, Tippett is working on pilot training and ensuring its mechanics are refined so it’ll be ready to race. Ultimately it’ll move like a gorilla—using all four limbs to walk or run—unlike us bipedal creatures. So if Tippett wants Prosthesis to race smoothly, what are the next steps for this sci-fi dream to become a reality?
But first, a walking spider robot
This isn’t the first time people have met Prosthesis. The giant mech has appeared at various tech events like CES 2017 and also Burning Man this past summer.
Burning Man is what actually inspired the inventor in Tippett before he began work on Prosthesis. Tippett was focused on engineering after graduating from the University of British Columbia’s mechanical engineering program. And thanks to a small grant from the Nevada festival in 2006, Tippett and fellow Vancouver engineers built the Mondo Spider, a mechanical walking spider propelled by hydraulic pumps and motors. It was later commissioned by CODE Live as part of the Vancouver 2010 Winter Olympic Games to switch to electrical energy, which enabled the Mondo Spider to operate relatively silently, charge from solar power, and perform indoors with no emissions.
In 2013, Tippett told Adam Savage’s Tested sitio: “If you can convert a 750kg walking spider from gas to electric, surely you can convert anything!”
The Mondo Spider project whetted Tippett’s engineering appetite. And when it began to circulate among the roboticists and general public, he was already blueprinting the specs for Prosthesis. Tippett wanted something bigger, faster, cooler.
“Let’s create a wild rollercoaster ride for the pilot,” Tippett remembers of those early days. “To be in a cockpit four metres off the ground, using your limbs to control the movements of a mech…it’s disorienting, terrifying, thrilling, all at once.”
Tippett knows all about thrilling: his hobbies include motor biking, mountain biking, and snowboarding. But tackling Prosthesis would prove to be daunting before he even stepped into the mech.
Building a bot body
When initially approaching Prosthesis, the specs themselves made Tippett’s head swirl. What does the suspension for an 8,000-pound walking machine need to do? With four legs versus eight, how could he ensure the mech is consistently balanced?
Getting the cockpit right was crucial for Tippett’s vision. Using a five-point harness, the pilot places their forearms into metal braces and legs in holders that wrap around his calves. Those limbs are then secured by items similar to a blood pressure cuff.
Tippett decided to forego mirroring the gait of a human and instead opted to riff off a gorilla’s walking patterns, complete with low-swinging “arms” and legs. In the cockpit, the pilot’s body movements control Prosthesis’ ambling: bend the elbow and the mech will attempt a squat. Push your arms and legs forward and Prosthesis will perform its version of a body roll.
To power its limbs, each of the mech’s legs is equipped with two hydraulic actuators. The “hip” actuator connects to the upper tip of the leg and allows it to swing forward and back. The second actuator connects to the backside of the four-bar linkage, Tippett says. Retracting this knee actuator shortens the leg and lifts it off the ground as the hip actuator swings the leg forward. When it clears the ground, the forward-moving leg extends to meet the ground. The hip actuator can pull the leg backward as the shock absorbers support the machine’s weight and cushion the ride.
“The sweet spot in all this is responsive movement,” Tippett says. “We spent weeks fine-tuning the harness, dampers, and bumpers in the cockpit to make sure everything works perfectly for the pilot.” He sighs. “Let’s just say, it’s really exhausting and challenging to pilot Prosthesis.”
As you might expect, Prosthesis’ lofty goals require many hits and misses. Tippett recalls toppling over in the mech several times, likening it to another sport. “With snowboarding, how often do you fall on your ass before you get it right?” he says. “It’s a lot of trial and error with Prosthesis, too.”
Getting the balance right was the first step for Tippett and his team, and now he’s working to get the mech smoothly walking—not running, not yet, Tippett cautions. Walk before you run, right?
“Look at people powering those monster trucks, how they have to get that choreography done right,” Tippett says. “It’s not much different with Prosthesis. It’s physically demanding. And in the end, the fans appreciate the human skill of powering these robots.”
At this point, he stresses, as he has done more than once in our interview, that “the machine is designed around the pilot—not the other way around.” Tippett adds how a mech should be an extension of the human body, creating that symbiosis feeling that remains difficult to replicate.