Integrated Servo Wheel for AGV/AMR: Selection Guide
An integrated servo wheel combines several drivetrain functions into a compact wheel-side assembly. Depending on the architecture, the module may integrate the wheel, motor, reduction mechanism, servo drive and communication interface.
For AGV and AMR projects, the main selection factors are wheel load, required wheel torque, travel speed, wheel diameter, available installation space, supply voltage, communication interface and functional-safety requirements.
Key Takeaways
- An integrated servo wheel combines wheel, motor, gearbox and servo drive in one unit; a hub motor places the motor in or around the wheel with little or no external transmission.
- JY Robot options: hub drive Ø106–130 mm, 5–5.6 N·m; common-body servo wheel Ø165/Ø180 mm, 22–75 N·m, 24–60 VDC; STO servo wheel 22–75 N·m with STO and Modbus RTU/CANopen; 5.5-inch hub motor Ø140 mm, 8.5/25.5 N·m, IP65.
- Select by wheel torque (T = F × r) and maximum load per driven wheel, not by motor power.
- Choose the STO version when the vehicle safety design requires it; STO does not replace the vehicle risk assessment.
- A separate motor, gearbox and wheel can be better for very high wheel loads, unusual ratios or special wheel materials.
1. Integrated Servo Wheel, Hub Drive or Hub Motor?
These terms are often used together, but they can describe different levels of integration.
An integrated servo wheel typically combines the wheel, motor, gearbox and servo drive into one compact unit. A hub motor places the drive system directly around or inside the wheel structure, reducing the need for a separate external transmission.
The correct architecture depends on vehicle load, packaging space, required torque and how much control electronics should be integrated into the wheel-side module.
2. Current JY Robot Integrated Wheel Options
| Series | Key Configuration | Typical Engineering Focus |
|---|---|---|
| Integrated Servo Wheel Hub Drive | Ø106–130 mm, 5–5.6 N·m, up to 5.4 km/h | Compact mobile robots |
| Common-Body Integrated Servo Wheel | Ø165/180 mm, 22–75 N·m, 24–60 VDC | Higher-torque AGV/AMR drive |
| STO Integrated Servo Wheel | 22–75 N·m, STO, Modbus RTU / CANopen | Applications requiring functional-safety interface |
| 5.5-inch Integrated Servo Hub Motor | Ø140 mm, 8.5 N·m rated, 25.5 N·m max | Compact robot and AGV platforms |
3. Start With Wheel Torque, Not Motor Power Alone
Motor power does not by itself determine whether an integrated wheel can move the vehicle. The wheel-side torque must be sufficient for rolling resistance, acceleration, slope and other operating resistance.
Required wheel torque is related to tractive force and wheel radius:
T = F × r
This is why wheel diameter and torque should be evaluated together. A larger wheel changes both vehicle packaging and the torque required at the wheel for the same tractive force.
4. How to Choose Between the Four Product Architectures
| Requirement | Product Direction |
|---|---|
| Small wheel diameter and compact robot chassis | Integrated Servo Wheel Hub Drive |
| Higher wheel torque for AGV/AMR traction | Common-Body Integrated Servo Wheel |
| Drive architecture requiring an STO input interface | STO Integrated Servo Wheel |
| Compact hub-motor architecture with IP65 protection | 5.5-inch Integrated Servo Hub Motor |
The final choice should still be checked against actual wheel load, required tractive force, duty cycle, floor condition and available installation envelope.
5. Voltage and Communication Affect Vehicle Integration
The drive voltage must match the vehicle electrical architecture rather than being selected independently. For example, the common-body integrated servo wheel series supports a 24–60 VDC drive-power range, while the control system must also be matched to the selected communication interface.
CANopen is useful when the wheel modules are integrated into a coordinated vehicle-control network. RS485 or Modbus RTU can be relevant for commissioning, parameter access or architectures that already use serial communication.
Communication compatibility should therefore be confirmed before the chassis and electrical harness are frozen.
6. When Is an STO Version Relevant?
Safe Torque Off, or STO, is relevant when the machine safety architecture requires a dedicated method to prevent the drive from producing motor torque after a safety command.
The STO version should not be selected simply because it has more functions. It is most useful when the vehicle-level safety design specifically requires this interface and the surrounding controller, wiring and safety logic are designed to use it.
The integrated STO interface does not replace a complete vehicle risk assessment or the rest of the machine safety system.
7. Wheel Load Still Has to Be Checked Separately
Integrated electronics do not change the basic mechanical selection rule: vehicle gross weight is not the same as the load carried by each driven wheel.
Battery position, payload location, chassis geometry and centre of gravity can all create unequal wheel loads. The maximum expected driven-wheel load should be checked against the selected module rather than dividing vehicle mass evenly by the number of wheels.
8. Practical Selection Sequence
- Calculate the maximum load carried by each driven wheel.
- Estimate required tractive force from rolling resistance, acceleration and slope.
- Convert required wheel force into wheel torque using wheel radius.
- Confirm required travel speed and wheel diameter.
- Check available installation space and ground-clearance limits.
- Match drive voltage and communication interface to the vehicle controller.
- Confirm whether the vehicle safety architecture requires an STO interface.
- Review duty cycle, floor condition and thermal requirements before final selection.
9. When an Integrated Servo Wheel May Not Be the Best Choice
An integrated servo wheel is attractive when compact packaging and simplified vehicle wiring are important, but it is not automatically the best architecture for every AGV or AMR.
A separate motor, gearbox and wheel arrangement may be preferable when the project requires unusual reduction ratios, very high wheel loads, special wheel materials, easier field replacement of individual drivetrain components or a mechanical layout that does not suit an integrated module.
For heavier vehicles that also require active steering, a dedicated drive-steering unit may be more appropriate. For vehicles using twin-wheel differential steering, see the differential drive module range.
10. Common Integrated Servo Wheel Selection Mistakes
- Selecting by motor power alone: wheel torque and actual tractive-force demand must also be checked.
- Ignoring wheel load: gross vehicle mass does not show the maximum load on each driven wheel.
- Choosing the smallest wheel only to reduce chassis height: wheel diameter also affects obstacle crossing, ground clearance and required wheel torque.
- Checking voltage but not communication: electrical supply and control interface both need to match the vehicle architecture.
- Choosing STO without a system-level safety design: the interface only has value when it is correctly integrated into the machine safety concept.
- Freezing the chassis before drivetrain selection: mounting space, cable routing and service access should be reviewed before the mechanical design is finalized.
11. Data to Prepare Before Selection
For an engineering review, prepare vehicle gross weight, maximum driven-wheel load, required travel speed, acceleration, maximum slope, floor condition, preferred wheel diameter, available installation envelope, supply voltage, communication interface and expected duty cycle.
If these inputs are available, the integrated wheel can be checked as part of the complete AGV or AMR drivetrain rather than as an isolated motor component.