SIMULATION / PHYSICAL COMMISSIONING
Build the physical workstation
A concise starting bill of materials for this xArm 7 cell. Vendor examples are candidates to confirm with the supplier, not a purchased or certified assembly.
Parts and where to buy
| Required part | What to order / supplier |
|---|---|
| Robot + controller | UFactory xArm 7, controller, manufacturer cables and wired emergency stop. Confirm mounting pattern, payload and tool centre of gravity. |
| Robotic pipette + tips | Hamilton ZEUS LT, PN 800888 is an OEM candidate: 1–1000 µL, tip detection, automatic ejection, 24 V and RS232/CAN. Request a quote, interface documentation and compatible CO-RE tips/racks for 100–200 µL. Requires a custom rigid mount and driver. |
| Rigid deck + station nests | At least 1.20 × 0.86 m, load-rated frame, bolted robot base, dowel-located plate/tip/tube nests and clamps. Use a Thorlabs metric breadboard family or local machined grid plate; size the structure for the robot loads. |
| Four cameras + lighting | Wrist, overhead and two fixed stereo views covering the approach workspace. For the stereo pair, consider Basler ace 2 a2A4096-30ucBAS: 4096×3000 color, global shutter, USB3 and hardware triggering. The simulation uses 3840×2880 stereo measurements. Use suitable fixed-focus C-mount lenses, rigid mounts and a measured pixel-to-mm uncertainty budget; wrist/overhead resolution can be lower. Add diffuse workspace light and two Edmund Optics backlights. Plan USB bandwidth and cable strain relief. |
| Station tags | Three 32 mm tags per station: plate 0–2, tips 3–5, sources 6–8, rigidly mounted at the offsets in labware.py. Use OpenCV DICT_4X4_50 and verify printed dimensions. Physical cameras also need measured intrinsics/distortion and mounting geometry; the hosted simulation provides these from its model. |
| Labware + waste | 96-well plate such as Corning 3599, four 15 mL tubes, compatible tip rack and enclosed tip-waste bin. Measure the exact well/tip geometry; the demonstration geometry is not a product-qualified model. |
| Independent validation | Use a traceable optical or dimensional reference to measure tip-to-well error across the workspace, payloads and tip lots. Choose the instrument for the required tolerance. |
| Volume validation | Calibrated balance, draft shield and temperature measurement; Sartorius semi-micro balances are candidates. Select readability and procedure for the actual volumes; validate with water before experimental liquids. |
| Local control + power | Ubuntu 24.04 PC with ROS 2 Jazzy, Ethernet to the controller, sufficient USB3 controllers, regulated pipette supply and isolated serial/CAN interface. Use the official xArm ROS 2 driver and serial-specific robot parameters. |
| Physical safeguarding | Enclosure, interlocked access and emergency-stop circuit designed by a qualified integrator. Pilz supplies safety control components; confirm compatibility with the actual UFactory controller. Measure stopping distances. |
Set it up in six steps
- Bolt and guard: anchor the deck and robot; clamp every station. Keep the controller outside the arm’s reach.
- Fit the real tool: machine its mount, enter mass/centre of gravity, update CAD/URDF collision envelopes and limits. ZEUS LT is not a drop-in replacement for the simulated 200 mm tool.
- Install optics: rigidly mount wrist/overhead cameras, two stereo cameras covering every approach point and controlled illumination. Lock focus and measure target dimensions.
- Connect local controls: implement and validate robot, camera and pipette adapters. Test stop/interlock behavior locally. Connect the web service through an authenticated gateway/VPN; never expose the robot controller directly to the internet.
- Measure and validate: establish the physical camera geometry and independently verify tip-to-well positioning. The simulation’s known geometry cannot be reused as a physical measurement. Repeat with realistic payloads, tip lots and temperature changes.
- Commission with water: slow dry runs, corner/interior well clearance checks, fault/stop tests, then gravimetric volume checks. Enable unattended protocols only after measured acceptance.
The hosted project is a simulation. Physical device drivers, safety wiring, manufactured mounts and hardware acceptance are still integration work. Buying these parts alone does not connect a real arm to the website.
For the detailed measurement methods and literature, see Precision research. For application incident handling, see Safety & recovery and Visual servoing.