
Overview
The EYOU RHU25L-80 is a harmonic-drive robot joint motor module for humanoid robots and other supported robotic applications. It combines a built-in driver, dual absolute encoders, and EtherCAT/CANopen communication in an 80 mm outer-diameter module. Selectable 50, 80, and 100 reduction ratios provide distinct output torque and speed values, while brake and non-brake versions are offered.
Features
- Harmonic reducer with built-in driver.
- Dual absolute encoder arrangement: motor side 17-bit and reducer side 19-bit.
- 48 VDC rated operating voltage; 24–48 VDC operating range.
- EtherCAT and CANopen communication protocols.
- Power (DC in, DC out), CAN FD (In, Out), EtherCAT (In, Out), and STO (1, 2) driver interfaces.
- Control modes: Profile Position (PP), Profile Velocity (PV), Profile Torque (PT), Cyclic Synchronous Position (CSP), Cyclic Synchronous Velocity (CSV), etc.
- Brake and non-brake options are available.
Specifications
For rows with three values, values are listed in reduction-ratio order: 50 / 80 / 100.
| Parameter | Value |
|---|---|
| Module model | RHU25L-80 |
| Reducer type | Harmonic |
| Motor rated power | 381 W |
| Motor rated torque | 1.04 N·m |
| Motor peak torque | 3.12 N·m |
| Reduction ratio | 50 / 80 / 100 |
| Joint rated power — life constraint | 113 / 115 / 98 W |
| Rated torque at 2,000 rpm input | 27 / 44 / 47 N·m |
| Average load torque at output | 38 / 60 / 75 N·m |
| Peak torque at output | 69 / 96 / 110 N·m |
| Maximum allowable external torque at output (instantaneous) | 127 / 179 / 184 N·m |
| Backlash | ≤20 / ≤20 / ≤20 arcsec |
| Rated speed at output — life constraint | 40 / 25 / 20 rpm |
| Peak speed at output | 79 / 50 / 40 rpm |
| Brake (B/N) | B/N |
| Dimensions (outer diameter × axial) | Φ80 × 80.5 mm |
| Weight (B/N) | 1.294 / 1.266 kg |
| Hollow diameter | 18 mm |
| Housing appearance (process color) | Black Stone |
| Reducer appearance (process color) | Outer Ring Blackened |
| Radial (dynamic/static) allowable load at output | 440 N |
| Axial (dynamic/static) allowable load at output | 440 N |
| Output bending moment | 62 N·m |
| Reducer torsional stiffness | 12,700 N·m/rad |
| Reducer input inertia (B) | 75.95 / 75.95 / 75.95 kg·mm² |
| Equivalent joint output inertia (B) | 189,875 / 486,080 / 759,500 kg·mm² |
| Rated operating voltage | 48 VDC |
| Operating voltage range | 24–48 VDC |
| Driver | Built-in |
| Encoder/bit | Dual absolute / motor side 17-bit & reducer side 19-bit |
| Driver interface (see terminal model description) | Power (DC in, DC out), CAN FD (In, Out), EtherCAT (In, Out), STO (1, 2) |
| Communication protocol (see communication description) | EtherCAT / CANopen |
| Control modes | Profile Position (PP), Profile Velocity (PV), Profile Torque (PT), Cyclic Synchronous Position (CSP), Cyclic Synchronous Velocity (CSV), etc. |
| Operating ambient temperature | -20–60 °C |
| Housing temperature rise | ≤60 °C |
| Noise | ≤60 dB |
| Life | >10,000 h |
Applications
- Humanoid robots
- Robotic arms
- Exoskeletons
- Quadruped robots
- AGV vehicles
- ARU robots
Documentation
- EYOU CANable — User Manual (PDF)
- EYOU RHU 25L 80 Drawing — Drawing (PDF)
- EYOU PHU RHU Series Joint CANopen EtherCAT Communication — Manual (PDF)
- EYOU Robot Joint Catalog — Robot Joint Product Catalog (PDF)
- EYOU RP Series EN V1.0 20260608 — User Manual (PDF)
- EYOU UART Debug Module — User Manual (PDF)
Visual Details
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Interfaces and Connections

Features and Design


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