How to Design Load-Bearing Structures for Heavy-Duty AGVs
📋 Key Summary
A standard AGV handles a few hundred kilograms; a heavy-duty AGV must carry tens of tons — a difference of nearly a hundredfold. The load-bearing structure is not just about making the chassis thicker. The chassis frame, drive system, and wheel system all need to be redesigned for tens of tons. This article explains the three core elements of a heavy-duty AGV's load-bearing structure — chassis frame load capacity, drive system matching, and wheel load distribution — and how they are verified and designed.
📌 Core Logic
Load-bearing structure = chassis frame load capacity + drive system matching + wheel load distribution.
All three must be designed and verified for tens of tons of load before the AGV can carry and move reliably.
AGVs come in different sizes and capacities. An AGV moving totes in a warehouse carries a few hundred kilograms; a heavy-duty AGV moving steel coils in a steel mill must handle tens of tons. With load capacities nearly a hundred times apart, the structural design is fundamentally different.
The load-bearing structure of a heavy-duty AGV is not just a thicker version of a standard AGV chassis. The chassis frame, drive system, and wheel system all need to be redesigned and reverified for tens of tons of load.
Here is how the load-bearing structure of a heavy-duty AGV is designed.
Chassis Frame Load Capacity: Supporting Tens of Tons
The chassis frame is the backbone of a heavy-duty AGV — it bears the full weight of tens of tons.
Strength means the stress in the chassis frame must stay within limits. With tens of tons of load on the frame, stress must be verified and the material strength must be sufficient; otherwise, the frame will deform or crack.
Stiffness means the frame must not deflect excessively under load. If the frame deflects too much, the saddle and load mounted on it will shift out of position, which can even affect traveling.
Chassis frame design starts with calculating the load capacity, then verifying strength and stiffness. When Kelude designs heavy-duty AGV chassis frames, it verifies strength and stiffness against tens of tons of load, referencing FEM 1.001 for structural strength requirements.
Drive System: Matching Power for Tens of Tons
For a tens-of-tons AGV to move, the drive system must be properly matched.
Drive power is calculated based on tens of tons of load plus traveling resistance. A 30-ton AGV typically requires over 10 kW of drive power just for startup. Starting, climbing, and accelerating a tens-of-tons AGV all demand sufficient drive power. Insufficient power means the AGV struggles to start and lacks climbing capability.
The drive motor is selected based on power and torque requirements. A heavy-duty AGV's drive motor must deliver high torque to push a tens-of-tons vehicle.
Kelude calculates drive power and selects drive motors based on tens of tons of load, ensuring the AGV can move and start reliably.
Wheel System Load Capacity: Single Wheel Load and Distribution
Tens of tons of load ultimately rest on the wheels.
Single wheel load capacity is the load each wheel bears. Tens of tons distributed across multiple wheels — a heavy-duty AGV typically has 8 to 12 wheels — means each wheel should not exceed 5 tons. The single wheel load must not exceed the wheel's rated capacity, or the wheel will be damaged.
Even wheel load distribution means the load is spread evenly across all wheels. Uneven distribution causes certain wheels to overload, leading to faster wear and shorter service life.
Wheel system design centers on sufficient single wheel load capacity and even load distribution. When Kelude designs wheel systems, it ensures the load is evenly distributed and each wheel stays within its permissible range, referencing GB/T 28264 Safety Monitoring and Management System for operating status recording requirements.
Design Verification: Calculating Load, Checking Strength and Stiffness
Verification is the core of load-bearing structure design.
Calculating the load means determining what the AGV must carry — the weight of the load plus the saddle and the vehicle's dead weight. Accurate load calculation is the foundation for all subsequent verification.
Checking strength means verifying that the stress in the chassis frame stays within limits. Under load, the stress at every point in the frame must be less than the material's allowable stress.
Checking stiffness means verifying that the frame's deformation stays within limits. Under load, the frame's deflection must be less than the permissible value.
Calculate the load, check strength, check stiffness — once these three verification steps pass, the load-bearing structure is qualified. Kelude's technical manager notes: "A heavy-duty AGV is not just a standard AGV with a thicker chassis. The chassis frame, drive system, and wheel system must all be designed from scratch for tens of tons of load — no shortcuts." Kelude follows these three verification steps as the standard procedure for heavy-duty AGV design.
Most Common Mistakes in Heavy-Duty Structure Design
The first mistake is modifying a standard AGV for heavy-duty use. A standard AGV's chassis frame, drive system, and wheel system are all designed for light loads; forcing it into heavy-duty service will cause structural failure. A heavy-duty AGV must be designed from the ground up.
The second mistake is calculating load capacity without a safety margin. If the tens-of-tons load is calculated right at the limit with no margin, any eccentric loading or impact will push it over. Load capacity must include a safety margin.
The third mistake is ignoring even wheel load distribution. Uneven load distribution overloads certain wheels, causing rapid wear. Kelude ensures the load is evenly distributed and each wheel stays within its permissible range.
Heavy-Duty Structure Design Comparison
| elements | function | design verification | failure consequences |
|---|---|---|---|
| chassis frame | load capacityframework | StrengthStiffness | Deformationcracking |
| drive | trolley propulsion | PowerTorque | hard starting |
| wheel system | load capacitytraveling | single wheelWheel load | wheel crushing |
Quick Reference of Standard Clauses for Heavy-Duty Structures
| Standard | key provisions | versusstructurerelationship |
|---|---|---|
| FEM 1.001 Crane Design Standard-2008 | structural strength requirements | chassis frameStrengthdatum |
| GB/T 28264 Safety Monitoring and Management System-2017 | operation status recording | operation logrequirements |
| TSG (Special Equipment Safety Technical Regulation) 51 Safety Technical Specification for Special Equipment-2023 Crane Safety Technical Supervision Regulation | safety technical regulations | operational safety requirements |
Heavy-Duty AGV Structure: FAQ
Q: What sets a heavy-duty AGV apart from a standard AGV?
A: The chassis frame, drive system, and wheel system are all fundamentally different. Standard AGVs are designed for loads of a few hundred kilograms, with lighter frames, smaller drives, and lighter-duty wheels. Heavy-duty AGVs, on the other hand, are engineered for loads of tens of tons, requiring a reinforced chassis frame, high-power drives, and a wheel system built for substantial load capacity. The core difference is a load capacity gap of nearly a hundredfold, which means the structure must be designed from the ground up—not just adapted from a standard AGV.
Q: How is the load capacity of a heavy-duty AGV determined?
A: It starts with the weight of the materials to be transported, plus a safety margin. First, establish the maximum weight of the load. Then, add a safety margin to arrive at the AGV's rated load capacity. This capacity must cover the material weight while also providing a buffer for uneven load distribution and impact forces. The key is to accurately calculate the material weight and then build in a generous safety margin—never spec it too close to the limit.
Q: Why is uniform wheel load distribution so critical?
A: Uneven wheel load distribution causes certain wheels to become overloaded. When a load of tens of tons is distributed across multiple wheels, any imbalance puts excessive stress on some wheels, leading to accelerated wear, a shortened service life, and even structural damage. The goal is to ensure the load is spread evenly across all wheels, keeping the single wheel load capacity within its permissible range. This is what gives the wheel system its longevity.
Q: Can a heavy-duty AGV handle inclines?
A: Yes, but within a limited grade. Heavy-duty AGVs are typically designed with a gradeability of up to 3 degrees. Steeper grades require increased drive power and greater wheel adhesion. In steel mills, AGV travel paths are kept as flat as possible. Where slopes are unavoidable, the drive system is verified against the specific grade. At Kelude, we factor the incline into the drive power calculations for every steel mill application—if the grade exceeds the limit, we adjust the route or add drive power.
The structural design principles for heavy-duty AGVs align closely with those for overhead crane structures. For a deeper dive into structural verification methods, refer to our guide on Overhead Crane Main Girder Design: Load Calculation, Finite Element Analysis & Deflection Checks.
Supporting tens of tons comes down to the structure. Kelude designs the chassis frame, drive system, and wheel load distribution for loads of tens of tons, with thorough strength and stiffness verification—ensuring a heavy-duty AGV that carries the load, moves reliably, and lasts.
