Annin Robotics Community

The PaMiLoCELL project is structured into five progressive development milestones:

#Milestone 01 – Robotic Arm & Basic Cell Assembly

• Complete the Annin Robotics AR4-MK5 mechanical assembly.
• Build the basic robotic cell structure.
• Install and configure the overhead 2D camera.
• Perform preliminary mechanical and electrical checks.

#Milestone 02 – AR4 Software & Motion Control

• Install and explore the latest AR4 control software.
• Learn robot programming, kinematics and motion control.
• Perform controlled tests of individual joints and basic robot movements.
• Verify positioning accuracy and repeatability.

#Milestone 03 – Electrical Control Panel & Functional Safety

• Assemble and wire the electrical control panel.
• Integrate the PLC, power supplies and control components.
• Install emergency stops, safety interlocks and safety relay.
• Verify and validate safety functions before automated operation.

#Milestone 04 – PLC Programming & Cell Automation

• Learn and configure the PLC programming environment.
• Develop control logic and operational sequences.
• Establish communication between PLC, robot controller and peripheral devices.
• Test interlocks, fault management and automated sequences.

#Milestone 05 – AI Vision, Sensor Fusion & Intelligent Sorting

• Integrate the 3D camera and additional material-identification sensors.
• Develop three interconnected functional layers:
• Sensory Layer: 2D/3D vision, data acquisition and material sensing.
• Cognitive Layer: AI-based object recognition, material classification and decision-making.
• Actuation Layer: Robot motion planning, gripping and sorting execution.
• Integrate and validate the complete perception-to-action workflow.

#First Application – Material Identification & Sorting

The initial objective is to demonstrate the automated identification, classification, picking and sorting of small waste objects using a robotic cell integrating industrial automation, AI vision and sensor fusion.

#Development approach: Build → Learn → Integrate → Test → Validate.

PaMiLoCELL | An independent technical development project by PaMiLoLAB.

#PaMiLoCELL #PaMiLoLAB #AnninRobotics #AR4MK5 #Robotics #IndustrialAutomation #PLC #MachineVision #ArtificialIntelligence #WasteSorting

Can a 0.15 mm deviation cause a robotic joint to bind?

During assembly of the Annin Robotics AR4-MK5, I noticed resistance over ~30° of rotation at J4. Loosening the J4 Timing Hub made it disappear.

📏 1. What I measured

• Required hub offset: 25.30 mm

• Measured: 25.15–25.21 mm

• Hub difficult to slide onto the shaft while keeping the pulley face square (90°).

A 0.15 mm offset alone is unlikely to explain the issue. More likely causes: an out-of-square hub, a tight/uneven bore, or excessive axial bearing preload.

🔍 2. Technical feedback from Community

• Keep the bearing contact face flat and parallel: avoid aggressive Dremel machining.

• If the bore is tight, lightly finish it without introducing play.

• Check printed hub thickness: ≤15 mm at the flat face.

• Tighten preload screws only until bearing play is removed and rotation remains smooth.

• Reprint the hub if its bore or face is distorted.

⚠️ 3. A disassembly mistake

I overlooked the different set-screw lengths:

• 1 × M4×10 engages the shaft alignment hole.

• 3 × M4×5 secure the hub around its perimeter.

• 4 × M4×5 face screws adjust bearing preload.

During removal, the longer screw was still engaged, damaging both the printed hub and the aluminum shaft.

🧱 4. Printed polymer vs. aluminum

The hub is designed to be 3D-printed (PETG or equivalent; 50% infill, 4 walls).

Aluminum adds machining cost without a demonstrated performance benefit for this application.

✅ 5. Next steps

Inspect the shaft; reprint the hub if needed; check the 25.3 mm position and squareness; set light preload; verify smooth, play-free rotation.

💡 LESSON LEARNED

A dimensional deviation is not automatically the root cause.

Check alignment, bore fit, bearing preload and screw lengths before modifying a component.

Thanks to the Community for the technical exchange!

❓ Repair or reprint: what criteria guide your decision?

🔧 6. Additional Assembly Issues Resolved

✅ Corrected blind or incompletely drilled holes.

✅ Eliminated minor belt and pulley interference points, ensuring adequate mechanical clearance for safe operation.

Building a robotic arm is not just a sequence of assembly steps. It is a series of small engineering decisions that affect reliability, serviceability and repeatability.

Here are 10 lessons from recent hands-on work:

1️⃣ SOLDERING & WETTING

Solder should wet the heated pin and conductor—not simply melt onto the iron. My trials with Sn99.3Cu0.7 and Sn63Pb37 reinforced the importance of surface preparation, flux and heat transfer. Tip temperature alone is not a quality criterion.

2️⃣ FASTENER DIMENSIONS

An M4×14 countersunk screw is measured including its head; an M3×16 socket-head screw is measured below the head. Geometry matters as much as nominal length.

3️⃣ DRILLING, TAPPING & FIT

For a conventional M4×0.7 cut thread, a Ø3.3 mm pilot hole is typical. Tap alignment, deburring, engagement depth and clearance all need checking. Never use tightening torque to force misaligned parts together.

4️⃣ PULLEYS & MATERIAL SELECTION

A timing hub transfers torque. Aluminium versus engineering polymer must be evaluated against loading, shaft fit, set-screw retention and dimensional stability—not appearance alone.

5️⃣ BACKLASH

Lost motion during reversal is not identical to belt elasticity or friction. Adjust tension without introducing excessive preload, then check smooth motion over the full range.

6️⃣ CABLE PROTECTION

Braided sleeving and cloth harness tape serve different functions. Abrasion, bend radius, strain relief and movement determine the correct choice.

7️⃣ 3-PIN CONNECTORS

For Hall sensor wiring, verify VCC, GND and signal against the actual pinout. Identical black wires and reversible-looking connectors demand clear identification.

8️⃣ J2 ENCODER GND

The 2×12 terminal block does not allow the A/B electrical connection to be identified by row position alone. Follow the manual, then verify electrically.

9️⃣ CONTINUITY TESTING

With all power sources and USB disconnected, I verified continuity between the J2 encoder GND terminal, terminal B/GND and Teensy 4.1 GND.

The multimeter BEEP confirmed continuity—not near-zero resistance or functional encoder performance.

🔟 INCOMING QUALITY & COST

Inspect real screw dimensions, corrosion and threadlocker residue before installation. For imported MK5 components, compare the total landed cost—not just the purchase price.

🎯 Main takeaway:

Assembly quality is built through measurement, inspection and controlled verification. Functional validation comes next.

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At this stage of the PaMiLoCELL project, I am carrying out a high-level brainstorming exercise to understand how the robotic cell could evolve before freezing the final layout.

The objective is not only to define the physical arrangement of the cell, but also to evaluate whether the project can develop into a technically credible and potentially fundable concept.

Step 0 – AR4 Operating Envelope Analysis

The starting point is the AR4-MK5 working envelope: maximum reach, inner non-reachable area, joint limits and the difference between theoretical reach and the actually useful workspace.

Step 1 – Base Cell Layout

The first concept uses a central inspection/pick area with sorting bins distributed around the perimeter, keeping the first development phase simple and easy to validate.

Step 3 – Safety + AI Vision Integration

The next evolution introduces the enclosure, E-stop/reset functions, PLC/safety architecture and AI Vision for object recognition and material sorting.

Step 4 – Modular Expansion with Conveyor

A modular/openable side could allow a small conveyor to be added later without redesigning the entire cell, moving from a static demonstrator toward a more dynamic sorting system.

Beyond the layout itself, I am also starting to look at the project from an innovation and funding perspective:

• What is genuinely innovative compared with the current state of the art?

• Which technical problem does the solution solve, and for whom?

• Can the concept improve existing solutions in performance, flexibility, safety, maintainability or cost?

• Is there a real market/user need behind the technical idea?

• How does it compare with existing and competing solutions?

• What are the main technical and market risks?

• Which elements could generate proprietary know-how, IP or potentially patentable solutions?

• Can the concept be validated through measurable technical and economic KPIs?

This changes the brainstorming process: the goal is no longer only “Can I build it?”, but also “Why should this solution exist, and what measurable value can it create?”

Questions I am currently asking myself:

1. What innovative aspects can I introduce compared with the current state of the art?

2. Is reducing construction and maintenance costs alone enough to create meaningful innovation?

3. Which measurable benefit would make this solution attractive to a real industrial user or investor?

4. Which technical result should I demonstrate first to reduce the project risk and strengthen a future funding application?

Note: The images shown in this post are AI-generated concept simulations created to support layout studies.

Analyze → Design → Validate → Improve

#PaMiLoCELL #PaMiLoLAB #Robotics #IndustrialAutomation #RobotCell #AR4MK5 #AnninRobotics #AIVision #MachineVision #FunctionalSafety #PLC #AutomationEngineering #MaterialSorting #Innovation #TechnologyTransfer #OpenSourceRobotics

While assembling the AR4-MK5 and studying industrial robots, I am realizing that robot motion is not only about motors, software and kinematics.

Between the motor and the joint there is a fundamental element:

the mechanical transmission.

Its architecture directly influences torque, stiffness, inertia, backlash, vibration, accuracy, payload and dynamic behaviour.

Main transmission families used in robotics include:

• Gear trains – robust and stiff torque transmission.

• Planetary gearboxes – compact, efficient and with high torque density.

• Cycloidal / RV reducers – high stiffness, low backlash and high load capacity, often suited to the main robot axes.

• Harmonic / Strain-Wave drives – compact, lightweight and with very low backlash, often used where low inertia is important.

• Timing belt & pulley systems – transfer motion between separated shafts and allow more flexibility in motor positioning.

• Direct drive – eliminates intermediate transmission stages, but requires high-torque motors.

A useful distinction is also between robot axes.

J1–J3 mainly position the arm and normally manage higher loads and moments, so torque, stiffness and load capacity are critical.

J4–J6 mainly control wrist orientation, where compactness, low mass and low inertia become increasingly important.

Where does the AR4-MK5 fit?

The AR4-MK5 uses a hybrid mechanical transmission architecture rather than a single transmission technology.

During assembly, several axes clearly show a chain based on:

Stepper Motor → Pulley → Timing Belt → Pulley → Shaft / Joint

combined with couplers, shafts, keys/keyways, bearings and mechanical reduction stages.

So the AR4 can be associated mainly with a:

Timing Belt & Pulley + Mechanical Reduction architecture.

This allows the motor to be positioned away from the joint and the transmission ratio to be adapted to the required motion.

The basic principle is:

Motor: high speed / lower torque → Reduction → Joint: lower speed / higher torque

or, in simplified form:

Tjoint ≈ Tmotor × i × η

where i is the reduction ratio and η the transmission efficiency.

This is also why small assembly details matter.

Incorrect belt tension, coupler tightening, key fit, shaft alignment, bearing preload or backlash can later appear as:

lost motion, vibration, reduced repeatability or positioning errors.

Key takeaway

Same 6-axis architecture does not mean the same mechanical behaviour.

Robot performance depends not only on software and kinematics, but also on what happens mechanically between each motor and joint.

For PaMiLoCELL, assembling the AR4-MK5 is therefore also a practical way to understand how belts, pulleys, shafts, bearings and reduction systems work together to create robot motion.

#PaMiLoCELL #PaMiLoLAB #AR4MK5 #Robotics #IndustrialRobotics #RobotMechanics #MechanicalTransmission #TimingBelt #Gearbox #MotionControl #RobotKinematics #MechanicalEngineering #Automation