Introducing the PP Series: Compact Planetary Robot Joint Modules

1. A New Addition to the PlaPivot Family

Until now, PlaPivot's catalog has centered on harmonic-drive rotary joint modules from 2.4 to 420 Nm — the right choice for industrial precision. But humanoid robotics, education platforms and budget automation projects have a different profile: compact dimensions, light weight, low cost, and joints that can absorb occasional impacts without damage. That is exactly the niche the PP planetary series fills.

The series keeps the integrated-module concept our customers rely on — motor, gearbox, dual encoders and communication in one sealed unit — while swapping the harmonic drive for a precision planetary gearbox. The result is a compact integrated servo joint family that is more impact-tolerant and more affordable, at a backlash level (≤12 arcmin) that is entirely adequate for the applications below.

2. The Model Lineup

Six models span rated torques from 0.2 to 10 Nm, all at 24 V with 50 RPM rated speed and CAN 2.0 control:

Model	Diameter	Length	Weight	Ratio	Max Power	Rated Torque	Peak Torque
PP-05	32 mm	33.4 mm	86 g	6	35 W	0.2 Nm	0.48 Nm
PP-08	40 mm	52 mm	189 g	36	36 W	1.0 Nm	2.2 Nm
PP-08D	40 mm	48 mm	199 g	36	36 W	1.0 Nm	2.2 Nm
PP-11	52 mm	64 mm	390 g	36	60 W	6.6 Nm	10 Nm
PP-11L	52 mm	82 mm	521 g	36	72 W	10 Nm	18 Nm
PP-11D	52 mm	61 mm	437 g	36	60 W	6.6 Nm	10 Nm

The D variants (PP-08D, PP-11D) use a shorter housing for the same torque — useful where axial space is the constraint. The PP-11L adds a longer motor section for the highest torque of the family.

3. What's Inside

The architecture follows the same proven layout as our larger modules, scaled down: a 4-point contact bearing supports the output, a precision planetary gearbox delivers the reduction, a frameless torque motor drives the input at high power density, and dual absolute encoders report true output position without homing. Communication runs over a CAN 2.0 bus with hardware FOC drive for smooth torque output.

4. Series-Level Specifications

Parameter	Value
Operating voltage	24 V DC
Protection rating	IP54
Motor type	Frameless torque motor (high power density)
Reducer	Precision planetary gearbox (ratio 6 or 36)
Feedback	Dual absolute encoders
Communication	CAN / CAN 2.0 bus
Backlash	≤12 arcmin
Noise	<60 dB @ 1 m
Operating temperature	−20 to +80 °C
Bearing	4-point contact bearing

5. Where the Planetary Series Shines

• Humanoid robots: the wrists, fingers and lower-torque joints of a humanoid need many small, light modules — see our humanoid joint guide for the full joint map. PP-05 (86 g) and PP-08 (189 g) are sized for exactly these positions.
• Small robotic arms & desktop robots: a 4–6-axis arm for research, bench automation or inspection fits entirely within this torque range.
• Education & STEM: the low entry price and simple CAN control make the series practical for university labs and robotics courses. Our education joint guide covers the selection logic.
• Motion control & orientation platforms: pan-tilt heads, camera gimbals and small turntables.
• Prosthetics & exoskeletons: light weight and 24 V battery compatibility suit wearable applications.

6. Planetary vs Harmonic: Which Do You Need?

Factor	Harmonic series (PP-52L…PP-170P)	Planetary series (PP-05…PP-11D)
Backlash	<1 / <0.5 arcmin	≤12 arcmin
Precision positioning	Excellent	Good for most applications
Impact tolerance	Moderate	Higher (tooth-to-tooth engagement)
Size / weight	Compact	Extremely compact (86 g smallest)
Voltage / bus	48 V, EtherCAT/CANopen	24 V, CAN 2.0
Best for	Industrial precision, higher torque	Humanoids, education, budget builds

For a deeper comparison of reducer technologies, our reducer comparison guide explains the mechanical trade-offs.

7. Wiring and Control Notes

• All models run on a single 24 V DC bus with CAN 2.0 signal lines; the modules are configured and tuned over the CAN bus.
• Supporting accessories are available: planetary communication/daisy-chain cables (XT30PW), power-communication splitter boards (one-to-four), and connection adapters.
• For integration questions, our CANopen protocol guide covers the bus-level details your controller needs.

8. Getting Started

The fastest way to evaluate the series is to order a single module, build a one-axis test rig and confirm your controller integration before scaling to a full arm — the same low-risk path we recommend in our small-batch guide. Datasheets, CAD models and CAN protocol documents are available on request.