Sidewalk Delivery Robot

Overview

A sidewalk delivery robot is a cooler-sized autonomous vehicle that carries food and small parcels the last mile from a restaurant or depot to a customer's door. It travels at walking pace on sidewalks rather than roads, which keeps kinetic energy low (a 35 kg robot at 6 km/h carries about 49 J, less than a jogging human) and places it under pedestrian rather than motor-vehicle regulation in most jurisdictions.

The machine is built around a Chassis with six wheels on two articulating Rocker Bogie Arm bogies. The rocker-bogie arrangement, borrowed from planetary rovers, lets the robot climb kerbs up to 180 mm while keeping all six Wheel Drive Module wheels loaded. On top sits the Cargo Bay, a 30-litre insulated tub closed by an electronically locked lid that only the paying customer can open.

How it works

Each wheel contains a gearless Hub Motor, an outer-rotor brushless machine with 20 Neodymium Magnet poles around a Stator Assembly, driven by its own Motor Controller running field-oriented control at 1 kHz. Skid steering (running left and right wheels at different speeds) turns the robot in place; there is no steering linkage to break or seal. Solid Solid Tires eliminate punctures, the dominant failure mode for fleet vehicles that roll over broken glass daily.

Perception is camera-first. Twelve Camera Module units give overlapping 360-degree coverage; a neural network running on the Compute SoC Module in the Compute Unit segments the scene into sidewalk, road, obstacles, and people at around 30 frames per second. An ultrasonic ring of eight Ultrasonic Sensor sensors covers the near field below camera view, and a single forward Crossing Radar watches for crossing vehicles before the robot commits to a road crossing, the highest-risk manoeuvre in its repertoire. Localization fuses RTK corrections from the GNSS Receiver receiver with visual landmarks against a pre-driven map, holding position error to a few centimetres even under tree cover where GNSS alone degrades.

The robot is autonomous for the boring 99 % of a trip. When confidence drops, construction blocking the mapped path, an ambiguous crossing, a curious dog, it stops and escalates to a remote operator who views the camera feeds over the Comms Module LTE link and either draws a corrective path or drives it directly. One operator typically supervises ten or more robots, which is the economic core of the product: the marginal delivery costs electricity and a sliver of human attention, not a driver's full hourly wage.

Cargo handling

The Insulated Cargo Tub is a double-walled expanded-polypropylene liner that keeps food above 60 °C or below 5 °C for roughly 40 minutes. The Electronic Lid Lock is a servo-driven rotary Latch Claw that captures a striker pin on the Cargo Lid; it releases only when the recipient taps the unlock button in the delivery app, which sends a one-time code over LTE. A Cargo Sensor (load cell plus IR beam) verifies that the merchant actually loaded the order and that the customer removed everything before the lid relatches.

Power and endurance

The Battery Pack is a 500 Wh, 36 V pack of seventy Li-ion Cell, 18650 cells in 10S7P, supervised by a BMS Board with a Thermal Fuse backstop. Average draw while rolling is about 80 W, giving six hours or ~30 km per charge. Packs swap by hand through a hatch in under a minute, so depot staff rotate batteries instead of parking robots at chargers.

Visibility and safety

A robot that shares space with pedestrians has to be seen and predictable. The Signal System includes addressable LED Strip turn and brake indicators, two Headlights, a Speaker for chimes and a polite "crossing now" voice, and the signature Flag Mast, a 90 cm whip flag that raises the robot's visual signature to car-driver eye level at crossings. Compliant Compliant Bumpers and the low speed cap mean a worst-case collision is a bump, not an injury; the safety Microcontroller watchdog in the compute unit cuts motor power independently if the main SoC hangs.