Area: Mobility and Logistics · TRL: 3 of 9 (proof of concept on paper) · Value-engineering target: $1,610 USD (estimated cost $5,065) · Difficulty: 4 of 5
Retrofit kit that turns a manual pallet jack into a powered, walk-behind unit with a UWB follow-me mode and layered stopping.
Exploded render · Detail render · Interactive 3D model · Concept blueprint (PDF) · General arrangement PLP-DWG-001 (PDF) · Sizing calculations · Prototype build plan · Design decisions · Review note
Most small sites already own one or more manual pallet jacks, and the jack's forks, pump and load wheels already do the hard part: lifting and carrying the pallet. What the operator lacks is drive and, for picking, a way to stop walking back to the handle. A bolt-on drive module on the steering yoke adds both without touching the jack's load path, and it can be removed to restore the jack. The kit uses parts a small shop can buy or make: AGV hub motors, a 24 V LiFePO4 pack, folded sheet metal, a safety laser scanner and UWB modules.
Keeping the design open matters because the likely users have no dealer service contract. Published drawings, a priced bill of materials and the sizing script let a maintenance person repair it, adapt the clamp to another donor jack, and check the safety numbers for themselves. The kit is a research prototype, not a certified industrial truck.
Moving loads by hand is one of the most common causes of work injury. In the United States, warehousing and storage recorded 4.8 injury and illness cases per 100 full-time workers in 2024 (BLS, Warehousing and Storage), about twice the private industry rate of 2.3 (BLS, Employer-Reported Workplace Injuries and Illnesses).
In the European Union, about three in five workers report musculoskeletal complaints, and 52 % of establishments name lifting or moving people or heavy loads as a risk factor (EU-OSHA, Healthy Workplaces 2020 to 2022). Powered trucks remove most of that effort, but small sites with a handful of staff are the ones least able to buy them.
| Industry | Use |
|---|---|
| Small warehousing and third-party logistics | Staging, put-away and loading without a forklift or a second worker |
| Grocery and retail backrooms | Receiving early-morning deliveries and restocking aisles, often by one person |
| Beverage and food distribution | Short, repeated moves of heavy pallets from dock to cooler or truck |
| Light manufacturing and workshops | Moving raw stock and finished goods between machines |
| Maker spaces and training centers | Shared material handling and teaching of safe powered-truck practice |
| Agricultural packhouses | Moving filled crates and bins from packing lines to cold rooms |
| Country or region | Why it matters there |
|---|---|
| United States | Warehousing injury rate about twice the private industry average (BLS); OSHA 1910.178 sets the training and modification-approval route |
| European Union | About three in five workers report musculoskeletal complaints (EU-OSHA); many small distributors and workshops share manual jacks |
| Japan | 29.3 % of the population was 65 or older on October 1, 2024 (Statistics Bureau of Japan); cutting push force and walking helps older staff keep working |
| India | Scored 3.4 of 5 in the World Bank's 2023 Logistics Performance Index (World Bank, Connecting to Compete 2023); small distributors that still move pallets by hand could gain a low-cost, locally repairable retrofit instead of importing a complete powered truck |
| Brazil | Scored 3.2 of 5 in the 2023 Logistics Performance Index (World Bank); small wholesalers and supermarkets that move pallets by hand are the target users |
| South Africa | Scored 3.7 of 5 in the 2023 Logistics Performance Index (World Bank); distributors and packhouses could fit a kit built from commodity parts and maintain it locally |
The starting point was Piaggio Fast Forward's gita, a personal cargo robot that went on sale on November 18, 2019 for $3,250. At the push of a button it pairs with its leader and uses visual sensors to follow them at up to about 2.7 m/s (6 mph), carrying up to about 18 kg (40 lb) (Piaggio Fast Forward press release, October 15, 2019). At the other end of the scale, follow-me operation for pallets comes as an option on full order-picking trucks: Jungheinrich's easyPILOT Follow lets its low-level order pickers follow an operator who wears a control unit (Jungheinrich). Nothing sat between them: a follow-me mode for a 1,000 kg pallet at a price a small site can pay. PalletPilot fills that gap by adding the follow-me mode, with layered stopping, to the manual jack the site already owns.
Small warehouses move pallets by hand, and powered pallet trucks with follow-me modes cost more than they can justify. Starting a 1,000 kg pallet on a manual jack takes about 270 N (estimate, PLP-CAL-001), at or past common ergonomic push limits. Basic lithium walkies now cost about $1,640, but follow-me trucks are forklift-class products. Full problem statement: docs/01-problem.md
Retrofit kit that turns a manual pallet jack into a powered, walk-behind unit with a UWB follow-me mode and layered stopping.
A sprung module with two 24 V hub motors clamps to the jack's steering yoke, with a 25.6 V 20 Ah LiFePO4 pack and the electronics in a low enclosure under the handle's sweep. In walk mode the operator steers with the handle and a walkie-style tiller head. With the kit fitted the handle turns about 40° each way, set by rubber stops (a bare jack turns about 90°), so the jack turns more widely than before: a turning radius of roughly 1.5 m about the load wheels, to be confirmed in the TRL 4 aisle test. In follow mode the operator wears a UWB tag and the motors steer by differential drive to hold a 1.5 m gap. Stopping is layered: a safety laser scanner watches a 0.80 m field ahead of the truck in follow mode, hardwired emergency stops act through a dual-channel safety relay and two contactors in series, and a contact bumper is the last layer.
The sizing note (PLP-CAL-001) finds that the kit moves 1,000 kg, starts on a 2 % ramp, works a 60-move shift with 24 % of the pack left and stops from 0.6 m/s in 0.36 to 0.70 m. Two targets are missed on paper: follow bearing accuracy (about ±16° against ±10°) and the 40 kg kit mass goal (42.9 kg, inside the 45 kg prototype limit). Value-engineering target: USD 1,610. Estimated cost of the constructable design: USD 5,065 (USD 3,455 over the target), because personnel detection now uses a safety-rated laser scanner. With the kit fitted the jack steers about 40° each way, against about 90° bare. Requirement status is in docs/03-requirements.md; decisions are in PLP-DDR-001 and PLP-DDR-002; the changes that made the design buildable are in PLP-DDR-003.
Full design precis: docs/02-concept.md
- Drive module with two 24 V, 200 mm hub motors and spring-applied brakes
- Dual-channel motor driver
- 25.6 V 20 Ah LiFePO4 pack with BMS
- Tiller control head with throttle, belly-reverse paddle and mode key
- Two hardwired emergency stops, a safety relay and two main contactors
- Safety laser scanner (PL d class) for personnel detection in follow mode, to ISO 3691-4
- Contact bumper (safety edge) as the last layer
- Three UWB anchors and an operator tag
- ESP32-S3 class controller
The working bill of materials is in bom/bom.csv.
The prototype build plan (PLP-BLD-001) shows how to make each of the 17 components and fit them to a donor jack in 15 steps, with a making sketch for every made part, close-ups of the joints and a picture for every step. Eleven parts are cut, drilled, welded or folded in a small fabrication shop; the motors, battery, electronics, safety edge, safety scanner and tiller head are bought. The subframe grips the jack's yoke plate between a top plate and a bolted jaw, so nothing on the jack is drilled. It is a plan, not a record of a build: building and testing to it is TRL 4 work. Decisions still open are in the design decisions register.
Moving machinery near people. The design uses hardwired emergency stops, walking-pace speed limits, a safety laser scanner stop layer in follow mode and a bumper that stops the unit on contact. The scanner layer is not yet built or tested, so follow mode stays at 0.15 m/s or less in a closed area until the layer is built and tested. Follow mode is treated as a driverless truck function under ISO 3691-4, so its personnel detection and stopping functions must meet that standard before any trial with people present. Contains a lithium battery pack. Use a BMS with cell-level protection, fuse the pack, and charge on a non-combustible surface. In the United States a powered pallet jack needs trained operators and the jack maker's written approval for modifications (29 CFR 1910.178). Builds are research prototypes, not certified industrial trucks. See docs/02-concept.md.
| Folder | Contents |
|---|---|
docs/ |
Problem, concept, requirements, calculations and design decisions |
cad/src/ |
build123d Python source, the source of truth for all geometry |
cad/step/, cad/stl/ |
Exported models for FreeCAD, other CAD tools and printing |
cad/drawings/ |
General arrangement PLP-DWG-001 (generated by cad/src/sheets.py) |
bom/ |
Bill of materials |
electronics/ |
KiCad schematics and PCB layouts |
firmware/ |
Microcontroller code |
media/ |
Renders, perspectives and photos |
build-log/ |
Dated prototyping notes |
Controlled documents follow the portfolio documentation standard. Each carries a document ID (PLP-PRC-001 for the precis), a version and a revision history. Branded PDFs are built with python .kit/render.py and attached to GitHub Releases when a document is tagged, for example PLP-PRC-001/v1.0.
Designed by Amish Chadha. See CONTRIBUTORS.md for roles. To cite this design, use CITATION.cff (GitHub shows it as "Cite this repository").
AI assistance (Claude) was used to accelerate concept renders, prototype documentation and first-pass sizing calculations. Design direction and all decisions are Amish Chadha's, recorded in this repository's decision records (docs/decisions/).
- Hardware (CAD, drawings, BOM, electronics): CERN-OHL-S v2
- Software (firmware, scripts, notebooks): MIT
A project of the Design Molecule lab.