Integrated robot joint actuator
MYACTUATOR RMD-X V4 integrated robot joint actuator
Planetary robot joint actuators with integrated driver, dual encoders and EtherCAT plus CAN bus, from the X2-7 to the X15-450; by the maker's naming the largest gives 450 Nm peak through a 20:1 planetary stage.
Key specifications
| Data / bus | EtherCAT, CAN bus |
|---|---|
| Peak torque (max) | 450 Nm |
| Ratio | 20–36:1 |
| Sizes | X2-7, X4-36, X6-60, X8-120, X12-320, X15-450 (X4-10 now discontinued; L-variants X4-10-L, X4-36-L, X6-50-L; X8-150, X10-200 hollow) |
| Encoder | dual encoder |
Summarised in our own words from Suzhou Micro Actuator Technology Co., Ltd.'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1 · Source 2 · Source 3
Notes on this data
Rechecked 2026-10-30: the technical parameter tables still do not load. The X4-36 page decodes RMD-X4-P36-36-E as P36 = planetary reduction ratio and 36 = peak torque (no unit printed). Peak torque 450 and ratio 20 are inferred from the X15-450 / P20 model code, not from a published table; treat as provisional until the datasheet (downloads-xseries) is read. Series page marks X4-10 discontinued.
Specify Motion is not affiliated with Suzhou Micro Actuator Technology Co., Ltd.. MYACTUATOR and RMD-X V4 are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a MYACTUATOR part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Hollow-shaft harmonic servo actuator: strain-wave gearing, motor, encoder and brake in one unit, run from a separate servo drive. Six frame sizes, from 48 VDC to 220 VAC.
| Published maximum | RMD-X V4 | MAH |
|---|---|---|
| Peak torque | 450 Nm | 800 Nm meets or exceeds |
| Rated torque | — | 557 Nm |
| Speed | — | 125 rpm |
Large-bore version of the harmonic actuator with a frameless 16-pole motor, giving a much bigger through-hole for cabling. Two sizes.
| Published maximum | RMD-X V4 | MAT |
|---|---|---|
| Peak torque | 450 Nm | 800 Nm meets or exceeds |
| Rated torque | — | 557 Nm |
| Speed | — | 102 rpm |
Harmonic actuator with an integrated German-made Synapticon Circulo servo drive on EtherCAT, with STO and optional FSoE functional safety.
| Published maximum | RMD-X V4 | MGM |
|---|---|---|
| Peak torque | 450 Nm | 459 Nm meets or exceeds |
| Rated torque | — | 267 Nm |
| Speed | — | 108 rpm |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What an integrated robot joint actuator is
An integrated robot joint actuator packages a brushless motor, a reduction gear, encoders, a servo drive and often a brake or torque sensor into one module that bolts in as a robot joint. Gearing may be planetary, strain-wave or cycloidal. Many are designed for legged robots, humanoids and cobots, with low gear ratios or quasi-direct drive to keep the joint back-drivable and responsive. Communication is typically over CAN or EtherCAT, with position, velocity and torque control modes.
When engineers choose an integrated robot joint actuator
Choose an integrated joint actuator to build robots faster with fewer parts, especially legged, humanoid, exoskeleton and collaborative robots. Back-drivable versions suit force control and impacts. The trade-offs are torque density, precision and industrial qualification: low-ratio designs trade output torque for transparency, and some units are aimed at research rather than production duty. For industrial arms with heavy duty cycles, a dedicated harmonic actuator or motor and gear set may be better.
How to specify the MYACTUATOR RMD-X V4
Send these with your enquiry and an engineer can confirm the right RMD-X V4 variant or an equivalent:
- Peak and continuous output torque (Nm)
- Output speed (rpm)
- Gear type and ratio
- Back-drivability and torque sensing
- Supply voltage (V DC)
- Communication interface and control modes
- Mass and size (kg, mm)
Common mistakes to avoid
- Using peak torque as continuous torque
- Ignoring thermal limits in legged robots
- Overlooking bus bandwidth with many joints
- Assuming research-grade units meet industrial life requirements
MYACTUATOR RMD-X V4: frequently asked questions
What is the MYACTUATOR RMD-X V4?
Planetary robot joint actuators with integrated driver, dual encoders and EtherCAT plus CAN bus, from the X2-7 to the X15-450; by the maker's naming the largest gives 450 Nm peak through a 20:1 planetary stage. Published series figures include peak torque 450 Nm, ratio 20:1, ratio 36:1. It is made by Suzhou Micro Actuator Technology Co., Ltd.; Specify Motion can help source it or propose an equivalent.
Who makes the MYACTUATOR RMD-X V4?
The MYACTUATOR RMD-X V4 is made by MYACTUATOR (Suzhou Micro Actuator Technology Co., Ltd.) and is listed here for engineers comparing options. Specify Motion is not affiliated with Suzhou Micro Actuator Technology Co., Ltd.; brand names are used only to identify the product.
What is the peak torque of the MYACTUATOR RMD-X V4?
The published series maximum peak torque is 450 Nm. Individual models and sizes in the RMD-X V4 range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the MYACTUATOR RMD-X V4?
Yes. On published figures, MAH and MAT are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
What is a quasi-direct-drive actuator?
A quasi-direct-drive actuator uses a high-torque motor with a low gear ratio, typically below about 10:1, so the joint is back-drivable and responds quickly to external forces. This suits legged robots and force control. The trade-off is lower output torque than high-ratio joints of similar size.
Why integrate the drive in a robot joint actuator?
Integrating the drive reduces cabling and lets each joint communicate over a shared bus, which simplifies robot design. It also allows the drive to sit close to the motor, improving control. The trade-off is that heat from both motor and drive must be managed inside the joint.
Further reading: How to select a harmonic actuator · Frameless motor sizing robot joints · Gearboxes and harmonic drives
Other integrated robot joint actuator series
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