Integrated robot joint actuator
RobStride 03 (RS03) integrated robot joint actuator
Quasi-direct-drive joint actuator with a 9:1 reduction giving 20 Nm rated and 60 Nm peak at 48 V, 200 rpm no-load, 14-bit absolute encoder and CAN 2.0 at 1 Mbps, in an 880 g package.
Key specifications
| Voltage (max) | 60 V |
|---|---|
| Temperature | -20–50 °C |
| Data / bus | CAN 2.0 (1 Mbps, extended frame) |
| Rated torque (max) | 20 Nm |
| Peak torque (max) | 60 Nm |
| Speed (max) | 200 rpm |
| Rated speed | 180 rpm |
| Supply | 24–60 VDC (48 V rated) |
| Feedback | 14-bit single-turn absolute encoder |
| Continuous current (max) | 13 A |
| Peak current (max) | 43 A |
| Ratio | 9–9:1 |
| Resolution (max) | 14 bit |
| Weight | 880 g |
| Insulation | Class B |
Summarised in our own words from Beijing Lingzu Times Technology Co., Ltd. (RobStride Dynamics)'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
From the RS03 user manual. The manual's parameter table lists GearRatio 64, which conflicts with the 9:1 ratio stated in section 1.4.5; 9:1 used here, confirm with the maker. Currents are phase current peaks. RobStride 01, 04, 05 and 06 exist but their pages are script-rendered and could not be read.
Specify Motion is not affiliated with Beijing Lingzu Times Technology Co., Ltd. (RobStride Dynamics). RobStride and RobStride 03 (RS03) 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 RobStride 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.
High-rigidity Wanshsin inline planetary with three backlash classes down to super-precision, for machine tools, automation and AGVs.
| Published maximum | RobStride 03 (RS03) | WSH |
|---|---|---|
| Peak torque | 60 Nm | 7,200 Nm meets or exceeds |
| Rated torque | 20 Nm | 2,400 Nm meets or exceeds |
| Speed | 200 rpm | 6,000 rpm meets or exceeds |
Right-angle version of the high-rigidity WSH, with a spiral bevel stage and ratios up to 200:1.
| Published maximum | RobStride 03 (RS03) | WSHR |
|---|---|---|
| Peak torque | 60 Nm | 4,200 Nm meets or exceeds |
| Rated torque | 20 Nm | 1,400 Nm meets or exceeds |
| Speed | 200 rpm | 6,000 rpm meets or exceeds |
Wanshsin inline planetary designed for high radial loads, offered in three precision classes.
| Published maximum | RobStride 03 (RS03) | WTH |
|---|---|---|
| Peak torque | 60 Nm | 6,150 Nm meets or exceeds |
| Rated torque | 20 Nm | 2,050 Nm meets or exceeds |
| Speed | 200 rpm | 6,000 rpm meets or exceeds |
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 RobStride 03 (RS03)
Send these with your enquiry and an engineer can confirm the right RobStride 03 (RS03) 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
RobStride 03 (RS03): frequently asked questions
What is the RobStride 03 (RS03)?
Quasi-direct-drive joint actuator with a 9:1 reduction giving 20 Nm rated and 60 Nm peak at 48 V, 200 rpm no-load, 14-bit absolute encoder and CAN 2.0 at 1 Mbps, in an 880 g package. Published series figures include voltage 60 V, temperature -20 °C, temperature 50 °C, rated torque 20 Nm. It is made by Beijing Lingzu Times Technology Co., Ltd. (RobStride Dynamics); Specify Motion can help source it or propose an equivalent.
Who makes the RobStride 03 (RS03)?
The RobStride 03 (RS03) is made by RobStride (Beijing Lingzu Times Technology Co., Ltd. (RobStride Dynamics)) and is listed here for engineers comparing options. Specify Motion is not affiliated with Beijing Lingzu Times Technology Co., Ltd. (RobStride Dynamics); brand names are used only to identify the product.
What is the voltage of the RobStride 03 (RS03)?
The published series maximum voltage is 60 V. Individual models and sizes in the RobStride 03 (RS03) 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 RobStride 03 (RS03)?
Yes. On published figures, Wanshsin WSH and Wanshsin WSHR 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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