ERDEN Utility platform selection
ERDEN Utility is opened as the second ERDEN platform, starting from a factory VEVOR four-wheel electric utility cart: roughly 51.2 by 25.6 inches, 125.7 lb, rated for 660 lb of payload, driven by a 500 W brushless system to about 5 km/h on 13 inch pneumatic tyres. The vehicle is factory-standard. No conversion work has been done, nothing has been measured first-hand, and every figure recorded so far is vendor-published. The purpose of opening the record now is to have somewhere honest to put the characterisation work as it happens, rather than reconstructing it later.
What we learned
- The specification sheet is a starting point, not a baseline. Nothing here has been verified against the vehicle.
- The unknowns worth writing down first are the ones that block everything else: how the drive is commanded, how the brake fails, and what the pack actually is.
- A platform rated to carry 660 lb changes what a mistake costs. The safety architecture is a prerequisite on this platform, not a later phase.
Next steps
- Take delivery and complete a full inspection and photographic inventory, as was done on Scout.
- Measure the accelerator, direction selector, and controller signalling before proposing any drive-by-wire approach.
- Characterise the pack, charging behaviour, and any auxiliary rail before selecting compute or sensing.
- Characterise brake behaviour on power loss and on controller fault, including holding capability on a slope.
Hardware referenced
- VEVOR 4-wheel electric utility cartVEVOR51.2 × 25.6 in flatbed cart, 660 lb rated payload, 125.7 lb
- 500 W brushless drive systemVEVOR (OEM)500 W brushless, approx. 5 km/h maximum
- OEM battery systemVEVOR (OEM)OEM pack, specification not established
- OEM motor controllerVEVOR (OEM)Factory controller, interface not established
Open challenges touched
Factory motor control interface is unknown
The vehicle's 500 W brushless drive is commanded by a factory controller with no published interface. Until the signalling between the accelerator, the direction selector, and the controller is measured, there is no way to say whether autonomy commands the existing controller, intercepts its inputs, or replaces it entirely.
Electrical baseline is unmeasured
Battery chemistry, pack voltage, capacity, charging behaviour, and the availability of any auxiliary rail are all unknown. Compute and sensor selection cannot be specified against a power budget that does not exist.
Braking behaviour and fail-state are uncharacterised
The factory electronic brake's behaviour on power loss, on controller fault, and under command is unknown, as is its holding capability on a slope with payload. On a vehicle rated to carry 660 lb, this is the unknown that keeps the platform stationary.
Decisions referenced
Start ERDEN Utility from a commercial electric utility vehicle
ERDEN Utility begins as a factory VEVOR four-wheel electric utility cart rather than a purpose-built work platform, so the engineering effort goes into control, safety, and autonomy rather than building a vehicle.
- A production work vehicle already solves load carrying, drivetrain, and durability at a payload rating we would spend a year reaching on our own.
- Starting from a known vehicle makes every conversion decision comparable against a documented factory baseline.
- The interesting risk on this platform is commanding a heavy machine safely, not fabricating one.
- Build a purpose-designed work platform — Rejected for now — mechanical work ahead of any autonomy learning, at a cost the programme has no evidence to justify yet.
- Scale ERDEN Scout up — Rejected — Scout's base is a development rover, not a load carrier, and the payload requirement is an order of magnitude apart.
Keep Utility a work platform, distinct from Scout
Utility is a load-carrying work platform; Scout remains a small observation and development rover. The two platforms share engineering practice, not a mission.
- Carrying material across a property and observing a property are different problems with different failure modes; one vehicle doing both would do neither well.
- Separating the roles keeps each platform's requirements honest, particularly around payload, speed, and stopping distance.
- Shared value comes from the registries, safety boundaries, and tooling — not from shared hardware.
- Treat Utility as a Scout variant — Rejected — it would inherit requirements shaped by a 10 kg rover onto a vehicle rated for 660 lb.
Characterise the factory vehicle before any conversion work
No control, compute, or sensing hardware is specified for Utility until the factory drive, braking, steering, and electrical systems have been measured first-hand.
- Every conversion option — command the factory controller, intercept its inputs, or replace it — depends on measurements nobody has taken yet.
- Specifying compute against an unknown power budget produces a bill of materials shaped by guesswork.
- On Scout, the largest schedule saving came from inspecting the base thoroughly before modifying it.
- Order conversion hardware in parallel with characterisation — Rejected — faster on paper, and historically produces parts that do not match what the vehicle turns out to be.