Summary
Boston Dynamics mechanical engineer Diane Heinle describes how the company endurance-tests the moving cables on its Stretch warehouse robot. Lab rigs cycle cable sections millions of times, while customer-site data helps set the target for expected use.
Boston Dynamics has described how it tests the moving cables on Stretch, its warehouse robot, in an interview with Diane Heinle, a mechanical engineer on the company’s Stretch Interconnects team. The cables route power and data through the robot; those running along its arm flex whenever Stretch moves a box.
The company’s approach combines accelerated laboratory cycling with estimates of how much work the robot is expected to do at customer sites. The aim, Heinle says, is to identify wear early enough to improve the design or adjust maintenance plans.
Testing for wear in moving cables
A cable that repeatedly bends can develop wear in its outer jacket or in the copper conductors inside it. Heinle says Boston Dynamics tests individual cable sections on separate rigs, cycling them millions of times and tracking when even small signs of wear begin. Other robot components, such as slip rings and clock springs, require different endurance tests.
To shorten the testing period, the lab runs its testers faster and applies more force than the cables would experience on the robot. Heinle says this can bring an issue that might appear years into field use to light within weeks. The company calls its endurance lab the “Tick-Tock Room” because the testers move back and forth continuously.
The test is not simply a contest to see how quickly a component can be broken. As Heinle describes it, the objective is to design for the conditions of warehouse operation, where Stretch needs to work reliably over repeated cycles.
Using warehouse data to set a target
Laboratory results need a target tied to expected use. Boston Dynamics collects data from customer sites to estimate how many cases a Stretch robot is likely to move over its lifetime. The company uses that estimate to set a target number of dynamic cable cycles, then tracks how many millions of cycles a design survives in testing.
If testing reveals a problem, the team can refine the cable design or update maintenance schedules to help avoid interruptions later in operation. Heinle also describes testing at Boston Dynamics and customer sites around the world, which the company uses to broaden its data on how designs perform.
The interview explains the testing process but does not give a specific cycle-life figure for a cable design or a field failure rate. Its central point is how the company connects accelerated component tests to an estimate of the repeated work Stretch is expected to perform.