In-Depth Analysis of Core AGV Mobility Components: Technical Applications and Selection Logic of Drive Wheels, Steering Wheels, and Casters

The article analyzes the technical characteristics, advantages, limitations, and selection logic of AGV drive wheels, steering wheels, and casters, explaining how these three core mobility components determine AGV precision, flexibility, load capacity, and overall system performance.

In intelligent manufacturing and intralogistics automation scenarios, the mobility system of an AGV (Automated Guided Vehicle) directly determines its motion accuracy, load capacity, spatial adaptability, and overall cost efficiency.

As the three core components of AGV mobility systems, drive wheels, steering wheels, and casters play a critical role in AGV design and application. Their technical characteristics, application suitability, and selection logic are key engineering considerations.

Differential Drive Systems: Technical Characteristics and Application Boundaries

Drive wheels are the core power output components of an AGV. Differential drive is currently the most mainstream motion solution for small and medium-load AGVs, enabling steering and movement control through the speed difference between the left and right wheels.

1. Core Motion Principle of Differential Drive

In a differential-drive AGV, actions such as steering, straight-line movement, and zero-radius rotation are entirely determined by the linear velocity difference between the two wheels.

The core motion relationship is:

ΔV = VL − VR

Where:

ΔV = linear velocity difference between the two wheels

VL = linear velocity of the left drive wheel

VR = linear velocity of the right drive wheel

When the two wheels rotate in opposite directions at equal speed, the AGV can achieve zero-radius rotation. The angular velocity satisfies:

ω = (VL − VR) / L

Where:

ω = angular velocity

L = center distance between the two drive wheels

2. Technical Advantages and Disadvantages of Differential Drive Wheels

Core Advantages

High motion flexibility

Supports zero-radius rotation and small turning radius, making it suitable for narrow workshop environments.

Low control complexity

Requires relatively lower motor precision and servo control capability, without the need for an independent steering mechanism.

Significant cost advantage

Simple structure and high component standardization help reduce overall BOM cost.

Core Limitations

Limited positioning accuracy

Wheel speed deviations and uneven floor friction can accumulate positioning errors, making it unsuitable for high-precision docking applications.

Restricted motion stability

Side slip can occur during high-speed turning, and trajectory deviation becomes more pronounced under heavy loads.

Weak scalability

Forward/reverse motion often requires redundant drive assemblies, and omnidirectional movement cannot be achieved.

3. Typical Applications of Differential Drive Wheels

Small and medium-load AGVs (≤500 kg) with relatively low positioning accuracy requirements

Early-stage line-following and towing AGVs

Cost-sensitive and simple automation retrofit projects

Steering Wheels: The High-End Integrated Driving and Steering Solution

AGV steering wheels integrate driving, steering, and load-bearing functions into a highly integrated module. They are the core solution for omnidirectional AGV movement and represent one of the most iconic technologies in high-end AGVs.

 4,Key Technical Reasons for the Limited Early Adoption of Steering Wheels

1. Size and Installation Height Constraints

Early imported steering wheel modules typically had a minimum installation height exceeding 200 mm, while low-profile latent AGVs generally required chassis heights below 150 mm with payloads below 500 kg. The dimensional mismatch limited practical integration.

2. Limited Functional Demand in Early Applications

In early automotive manufacturing scenarios, single-direction line following was dominant, and differential drive systems were sufficient.

Bidirectional motion required dual differential drive assemblies, increasing both cost and complexity, which reduced the practical advantages of steering wheel systems at the time.

3, Core Technical Advantages of Steering Wheels

Omnidirectional movement capability

Independent steering and driving functions support 360° steering, enabling lateral movement, diagonal movement, and zero-radius rotation for extremely confined spaces.

High motion accuracy

Integrated servo steering systems can achieve positioning accuracy up to ±5 mm, meeting high-precision production line docking requirements.

High structural integration

A single steering wheel module can replace multiple differential drive assemblies, simplifying chassis structures and improving space utilization.

Strong load adaptability

Suitable for applications ranging from light-duty AGVs to heavy-duty industrial AGVs with outstanding industrial-grade reliability.

4, Development Trends of Steering Wheel Technology

Miniaturization

Domestic manufacturers have overcome height limitations and introduced ultra-low-profile steering wheel modules below 100 mm, suitable for latent AGVs.

Modularization

Integrated designs combining drive, steering, braking, and sensing functions enable plug-and-play deployment.

Higher precision

With absolute encoders, steering repeatability can reach ≤ ±0.1°.

5,Typical Applications of Steering Wheels

Omnidirectional latent AGVs

Lift-type AGVs

Automotive manufacturing, 3C electronics, and new energy industries requiring high precision and compact maneuverability

Heavy-duty AGVs with payloads ≥1000 kg

Casters: Critical Supporting Components for AGV Stability

Casters (idler wheels) are passive components without driving or steering capability. They mainly provide load support, stability, and following motion functions, serving as essential stabilizing components in AGV mobility systems.

Caster selection directly affects overall vehicle smoothness, service life, and operational stability.

6,Key Technical Considerations for Caster Selection

Material Selection

PU (polyurethane) wheels are suitable for cleanroom environments; rubber wheels for rough floors; nylon wheels for heavy-load applications.

Structural Configuration

Fixed casters improve straight-line stability, while swivel casters enhance maneuverability. Appropriate combinations should be selected according to

application requirements.

Precision

Bearing precision and wheel roundness directly affect operating noise and trajectory deviation.

7,Typical Applications of Casters

Passive support for all AGV chassis systems

Fully passive lightweight AGV platforms (without powered drive wheels)

Auxiliary load-bearing components in heavy-duty AGVs

Technical Comparison and Selection Guide for the Three Core Components

Component Type Motion Capability Control Accuracy Cost Level Suitable Load

Core Selection Principles

Cost priority with low precision requirements

→ Differential drive wheels + swivel casters

Limited space with high precision requirements

→ Steering wheels + fixed casters

Heavy-duty and large-tonnage applications

→ Multiple steering wheel modules + heavy-duty casters

Future Trends in AGV Mobility Systems

The evolution of AGV mobility systems is essentially driven by continuous performance improvements and optimization of drive wheels, steering wheels, and caster technologies.

Differential drive wheels dominate the low-end market due to their cost advantages.

Steering wheels have become the core technology of high-end AGVs because of their omnidirectional and high-precision capabilities.

Casters continue to play an indispensable supporting role across all AGV platforms.

Under the trend of intelligent manufacturing upgrades, steering wheel technology is rapidly evolving toward:

• Miniaturization

• Integration

• Higher precision

Meanwhile:

Differential drive systems are becoming more application-specific and cost-focused.

Casters are advancing toward higher load capacity, lower noise, and longer service life.

The collaborative optimization of these three core components represents the key technological pathway for improving overall AGV performance.