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83 Kalmar AutoStrad | In operation of the charging terminals, the AutoStrads can drive to the nearest one when needed. The charging system, known as the Kalmar FastCharge, is typically constructed as a charging pole that extends its pantograph connector downwards onto a rail atop the straddle carrier. It charges using a fast DC connection – recharging for 5-7 minutes will typically enable another hour’s worth of operating time. The pantograph’s charging is thus far more efficient than conventional automotive-style charging ports, in which a technician or other worker would have to approach the vehicle to plug in a HV cable, with the safety risk of having a person entering the carriers’ operating zones. “The exact location of each charging point needs to be decided differently for every terminal,” Alho says. “We and the terminal operators will plan where to place them to cause the least chance of disruption when a carrier is parking on them. “Generally though we want to put down as few charging stations as possible, to minimise the price of the overall integration, although having too few stations brings the risk of creating a bottleneck in the operations if carriers start having to queue while waiting for their turn to charge.” Post-operational maintenance Schedules and practices for carrier maintenance will also vary between terminals. After their two-day stints, they can undergo a range of checks and tasks to check their safety. These include cleaning the laser rangefinders and other sensor equipment near the ground, inspecting for oil leaks, and testing the responsiveness of the onboard electronics and the traction and lifting machinery. Alho adds that the spreaders and diesel engines need the most maintenance, as they contain the most mechanical parts, and thus the downtime and maintenance costs associated with the latter can be eliminated by going all-electric. “Given that no human drivers or technicians are meant to enter the autonomous carriers’ workspace, the maintenance standards for these vehicles should always be higher than those for users’ manned vehicles, electric or not,” he says. “Smooth execution of logistics plans depends on not having any autonomous carriers suffering defects or breakdowns in the first place. So whenever one of them enters the demarcated interchange area, between the active terminal area and their parking yard, it’s a good idea to run a wider range of inspections and tests – or more frequent ones – than would be typical, before returning it to work.” He adds that the mindset for automated equipment maintenance should be focused more on preventive maintenance than solely corrective maintenance. As with many unmanned systems, Kalmar One’s component connectivity, data storage and analytics engine can provide performance monitoring that could produce valuable predictions to help steer maintenance practices in this direction. The future As Kalmar increasingly automates its cargo terminal solutions, which include cranes and organisational software as well as straddle carriers, the question arises of what more the company can automate. “One approach we’re developing is improving our software’s intelligence on the sustainability side of cargo work – having or running analytics on energy scaling and related areas to save more fuel and battery energy,” says Tuulkari. “We also want to find ways to deploy our automation technologies more easily on site. Many terminals are still wary of adopting autonomy in their straddle carriers, as turning them into UGVs has an impact on every part and operating process of the terminal.” Unmanned Systems Technology | December/January 2021 AutoStrad straddle carrier Diesel-electric, hybrid-electric, or battery-electric Dimensions: 15 x 10 x 5 m Maximum ground speed: 30 kph Maximum lifting speed: 30 m/minute Maximum carrying capacity: 40,000 kg (single-container configuration) or 50,000 kg (twin-lift configuration) Specifications A group of AutoStrads operating at Patrick Fisherman Island Terminal in Brisbane, Australia