AGV Drive Wheel Selection Guide: Load, Torque and Drive Architecture

Selecting an AGV drive wheel is not just a question of vehicle weight or motor power. The drivetrain must provide enough wheel load, tractive force and torque while fitting the required speed, floor condition, installation space and steering architecture.

This guide provides a practical starting point for choosing drive wheels and drive modules for AGV and AMR platforms.

1. Start With Actual Wheel Load

Total vehicle mass should not simply be divided by the number of wheels. Battery position, payload location, centre of gravity and chassis geometry can create different loads at each wheel.

The maximum expected load on each driven wheel should be established first. This determines whether the wheel, bearing structure and drive module have sufficient mechanical capacity.

2. Calculate the Required Tractive Force

The drive system must overcome rolling resistance, acceleration resistance and grade resistance. A simplified screening relationship is:

F = F_rolling + F_acceleration + F_grade

Additional allowance may be required for floor joints, contamination, turning resistance or application-specific conditions.

For a detailed calculation method, see the AGV tractive force and wheel-load calculation guide.

3. Convert Tractive Force Into Wheel Torque

Required wheel torque depends on tractive force and wheel radius:

T = F × r

This means wheel diameter cannot be selected independently from torque. A larger wheel can improve obstacle crossing and ground clearance, but it also increases the wheel torque required for the same tractive force.

4. Choose the Drive Architecture

5. Match the Architecture to the Required Vehicle Motion

If the vehicle mainly travels forward and reverse and can turn by controlling the speed difference between two driven wheels, a differential drive module can provide a mechanically straightforward solution.

If individual wheel direction must be actively controlled for docking, special chassis geometry or higher manoeuvrability, consider a drive-steering unit.

For compact wheel-side integration, see the integrated servo wheel selection guide.

If true lateral or omnidirectional motion is required, compare Mecanum and omni-wheel architectures before freezing the chassis layout.

6. Wheel Diameter, Speed and Floor Condition Must Be Checked Together

Wheel diameter affects more than vehicle height. It also changes wheel torque requirement, obstacle-crossing behaviour, ground clearance and available packaging space.

Required travel speed determines wheel rpm and affects motor and reduction-ratio selection. Floor joints, gaps, ramps and surface contamination can also increase resistance or reduce usable traction.

A small wheel may help reduce chassis height, but it should not be selected before checking floor conditions and the required wheel torque.

7. Voltage, Controller and Feedback Interface

The drive-wheel system must match the vehicle electrical architecture. Confirm supply voltage, motor controller type, encoder feedback, braking requirements and communication interface before finalizing the wiring harness.

Depending on the product architecture, interfaces may include CANopen, RS485, Modbus RTU or other controller-specific signals. The available interface should be verified against the selected product configuration rather than assumed from the wheel type alone.

8. A Practical AGV Drive Wheel Selection Sequence

1. Define vehicle gross weight and maximum payload.
2. Calculate actual load carried by each driven wheel.
3. Estimate rolling, acceleration and grade resistance.
4. Calculate required tractive force and wheel torque.
5. Define travel speed and acceptable wheel diameter.
6. Choose differential, drive-steering, integrated servo or omnidirectional architecture.
7. Check floor condition, wheel material and traction.
8. Confirm voltage, controller, feedback and communication interface.
9. Verify installation envelope, ground clearance and service access.

9. Common AGV Drive Wheel Selection Mistakes

• Selecting by vehicle weight alone: actual driven-wheel load and load distribution must be checked.
• Selecting by motor power alone: required tractive force and wheel torque are more useful engineering inputs.
• Ignoring floor condition: joints, ramps, contamination and surface friction can change real traction demand.
• Choosing wheel diameter only for chassis height: wheel diameter also affects torque requirement and obstacle crossing.
• Choosing a drive type before defining vehicle motion: steering, differential and omnidirectional architectures solve different motion requirements.
• Freezing the chassis too early: installation envelope, ground clearance, cable routing and service access should be reviewed with the drivetrain.

10. Project Data to Prepare Before Selection

Before requesting a drive-wheel recommendation, prepare the vehicle gross weight, payload, driven-wheel load, maximum speed, acceleration, maximum slope, floor condition, preferred wheel diameter, available installation space, supply voltage, controller interface and expected duty cycle.

With these inputs, the drive wheel or drive module can be evaluated as part of the complete AGV or AMR chassis rather than as an isolated component.