Robot stick-handler

Engineering students at the University of Waterloo and their prof have developed a robot that replicates the perfect slapshot to test composite hockey sticks for fractures and breaking points

June 30, 2011   by Matt Powell

A group of University of Waterloo engineering students are using a robot they developed that accurately mimics a slap-shot to uncover the mystery behind the constant breaking of composite hockey sticks.

The project started five years ago when engineering professor John McPhee realized a robot could test hockey sticks the same way golf manufacturers test golf clubs.
“Professor McPhee realized there was a pretty significant issue with stick breakage, especially surrounding these new composite sticks four or five years ago,” says Jean-Samuel Rancourt, 22, a mechanical engineering student at the Waterloo, Ont. university and the business brain of the operation. “He had worked with golf companies before and thought ‘why not use the same technology?’”

You won’t find many wooden hockey sticks today. Now they’re made of composite materials such as graphite, glass and Kevlar that are layered according to desired stiffness (most have 15 layers) and held together with a resin. These sticks are much lighter than wood ones and generate more power, allowing players to shoot a puck harder, but durability is a major issue. It’s common for NHL players to snap sticks in two after winding up for a one-timer or taking a slash from an opposing player.

The Waterloo engineering students estimate that college and professional hockey players go through 24 to 36 sticks a year. At about $250 a pop, teams are spending thousands of dollars a year per player to replace them.

To solve the problem, the team at Hockey Robotics, a start-up of five mechanical and mechatronics engineering students, developed the SlapshotXT with the help of $100,000 in funding from private and federal government sources. This prototype generates enough power to shoot a puck at 110 miles per hour.

But what differentiates this robot from its golf counterparts are the two synchronized arms that replicate the perfect slap-shot.

“It was fairly tricky to coordinate the arms because if they weren’t perfectly synched, they’d go in opposite directions,” says McPhee.

The robot is a lefty, so the arm drives the motion and does most of the work, while the right arm is synchronized to follow the trajectory of what the left arm should be doing. Six-axis adjustability properly simulates shots in different scenarios and the robot also adjusts the lie angle of the stick’s blade.

NHL All Star
A brushless DC servomotor (generating about four horsepower, driving at a continuous rate of 12 amps) powers a sophisticated gear, sprocket and belt system and communicates with a real-time controller that sends data to a National Instruments LabView application software suite that generates the motion profile.

“The robot has topped out at 60 miles per hour right now, but it’s because the battery requires 240 volts, and we’ve only been able to test with 120 volts,” says Rancourt. “Our goal is to eventually break the NHL record.”

That’s currently held by Boston Bruins defenceman Zdeno Chara, who fired a 105.9 miles per hour shot at this year’s NHL all-star game.

The robot’s body is made of steel framing with aluminum arms to simulate the average body weight of a grown man while minimizing the weight from the machine’s central axis.

The team employed a number of local Waterloo machines shops and metal manufacturers for the parts and sub-assemblies, including Dun Rite Manufacturing Ltd., J.A. Machining and AHBM Systems.

Initial testing procedures were similar to those used by video game companies.
The team used OptoTrak technology to create 3D images and gathered data that explains necessary movements, how energy was being dispersed and the amount of torque the mechanism would need to make testing as realistic as possible.

Shooters were outfitted with motion markers tracked by the system’s OptoTrak motion capture cameras (in some cases, as many as 12 were used) to replicate realistic human movement.

SlapshotXT robot winds up for a 60 mph shot.

With the prototype complete and initial testing underway, the team is already thinking about potential upgrades, which will be easy to go after, says Tristan Lehari, 22, who is the project’s mechanical structure and design lead. “The robot is built on a number of sub-assemblies so taking it apart to make the upgrade won’t be overly difficult.”
Going forward, the team is looking to place sensors along the length of a hockey stick and use the SlapshotXT to identify its weakest areas.

“We’ll be able to identify where the most stress is, where the stress fractures are and where the sticks are breaking,” says Chris Goodine, 22, who is the electrical and data acquisition lead.

Much effort has gone into making sticks light, so the team also plans to coat them in a nanomaterial that would make them stronger.

The company is also in the midst of developing a “Stick Impactor” that will replicate surface damage sustained during play, and compare the true durability of materials, design and construction.

“We’re noticing a new stick right out of the box probably won’t break after a few slashes,” says Goodine. “But these lighter sticks are becoming increasingly prone to micro-fractures or weak spots that can severely affect performance.”

The team believes it has found a way to fill a void since there are no testing procedures like the SlapshotXT available to hockey stick manufacturers.

Hockey Robotics plans to commercialize its research in July by offering to sell the test data to the world’s 40 or so stick makers.

“Our idea is to fill that niche,” says McPhee. “This could truly revolutionize the way sticks are manufactured and designed.”
If he is correct, the fledging robotics company will have scored a big win for Canadian innovation and the world of hockey.

Matt Powell is an online reporter with E-mail

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