Boston Dynamics unveils Stretch Gen 2 trailer-unloading robot, built for reliability

Boston Dynamics introduced Stretch Gen 2 this week, the newest version of its autonomous mobile robot that unloads trailers. The company said it built the machine to maximize uptime and streamline maintenance, and that the earlier model has logged more than 100,000 operating hours and handled tens of millions of boxes.

Brian Donnelly, the company's vice president and general manager of logistics robotics, said in an interview with The Robot Report that work on the new version lasted around two and a half years.

“When we made the first generation of Stretch, we were focused on trying to get a product out into the market as fast as possible and really get it in customers’ hands and get it operational”

Brian Donnelly, vice president and general manager of logistics robotics, Boston Dynamics

Fewer cables, sturdier parts

The Waltham, Massachusetts-based company said it removed 81% of the robot's internal cabling, about half a mile's worth. Donnelly said Hyundai helped Boston Dynamics obtain a cable harness through its automotive supply chain. The robot also uses automotive-grade connectors meant to withstand vibration from fast, high-torque box handling and driving over uneven floors.

Continuous rotation joints can turn beyond 360 degrees, so they no longer hit hard stops. The emergency stop now sits lower and is recessed, and new exterior panel materials make it less likely that a falling box will trigger an unintended stop or break a panel, according to the report.

Gripper picks multiple boxes

The upgraded gripper has a valve in each suction cup, which Donnelly said lets the robot pick several boxes in one arm motion and raises throughput. Each cup is individually sensed, so suction is applied only when a box is in good contact, which reduces vacuum pump power use, he said.

Stretch Gen 2 can unload up to 1,000 cases per hour, a rate that depends heavily on case weight and how neatly cases are stacked. It has a battery that lasts two shifts and a fast charger that reaches 90% in about 75 minutes. The report said a pre-trained vision system can detect most packages without programming.

Faster servicing and software updates

A full swerve drive swap can now be done in one hour, whereas it could previously take an entire day, the report said. New onboard diagnostics and maintenance tools are intended to let customers' own maintenance teams handle more routine service.

Boston Dynamics said it will regularly release software updates improving case detection, motion planning, pick strategies and world modeling without hardware changes. Donnelly said the most recent update raised the unload rate by 24% across its fleet of fielded robots, and that new software arrives about monthly.

Donnelly said Stretch Gen 2 is already running at multiple customer sites and that the company deploys robots at existing sites within two weeks.