The drive configuration of an AGV or AMR directly affects its movement flexibility, load capacity, steering accuracy, chassis height, control complexity, and manufacturing cost. Each drive type has its own suitable applications, and no single solution can meet every requirement. The right choice should be based on the vehicle load, travel speed, floor conditions, installation space, and required movement.
No.1 Horizontal Steering Drive Wheel
A horizontal steering drive wheel combines driving, steering, speed feedback, angle feedback, and braking in one module. By controlling the drive motor and steering motor, the system can accurately adjust the travel speed and steering angle.
The drive motor is usually installed horizontally, which helps reduce the overall height. This makes the design suitable for underride AGVs, low-profile AMRs, and vehicles with limited installation space. A single steering drive wheel can support forward and backward travel and turning. With two or more independently driven and steered wheels, together with a suitable chassis layout and control system, the vehicle can also rotate in place, move sideways, and travel diagonally.
Continuous 360-degree steering depends on the cable routing and structural design. Standard cables may become twisted during rotation, so some products use steering limits. If continuous rotation is required, a slip ring or another anti-twisting design is usually needed.
No.2 Vertical Steering Drive Wheel
A vertical steering drive wheel also combines driving, steering, speed feedback, angle feedback, and braking functions. Unlike a horizontal design, its motor and transmission are usually arranged vertically. This results in a greater overall height but requires less horizontal space.
This structure is suitable for AGVs and AMRs with limited chassis width but enough vertical space. The vertical layout can also make the motor and transmission easier to design as modular units. However, it does not automatically provide better outdoor, waterproof, obstacle-crossing, or explosion-proof performance.
Environmental performance mainly depends on the sealing design, protection rating, bearing configuration, connectors, corrosion protection, and certifications. Climbing ability depends on motor power, gear ratio, wheel traction, and vehicle center of gravity. Obstacle-crossing ability is mainly affected by wheel diameter, ground clearance, suspension, and chassis design. Continuous 360-degree steering also depends on the slip ring, cable routing, or steering limit structure.
No.3 Differential Drive Unit
A two-wheel differential drive usually consists of two independently powered wheels and several supporting caster wheels. When both drive wheels rotate at the same speed in the same direction, the vehicle moves straight. When the wheel speeds are different, the vehicle turns. When the wheels rotate in opposite directions, the vehicle can rotate in place.
This drive system has a simple structure, relatively low cost, and mature control technology. It is widely used in warehouse AMRs, delivery robots, and light- to medium-duty AGVs. It does not require an additional mechanical steering system, so the chassis layout is compact and maintenance is relatively easy.
However, a differential drive wheel cannot move sideways directly. During in-place rotation, the wheels may experience sideways slip as well as rolling motion. This can increase tire wear and steering resistance, especially under heavy loads, on high-friction floors, or with a wide wheel track. Small differences in wheel speed, wheel diameter, or floor friction may also cause the vehicle to drift during straight travel, so encoders and control algorithms are needed for continuous correction.
No.4 Mecanum Wheel Drive
A Mecanum drive usually uses four wheels. By controlling the speed and direction of each wheel, the vehicle can move forward, backward, sideways, diagonally, and rotate in place. It does not require a separate steering mechanism and is suitable for light- to medium-duty indoor applications with limited space and flat floors.
However, Mecanum wheels require good floor flatness and accurate control. Their roller structure is also more likely to produce vibration and wear. For heavy loads, high traction requirements, or floors with many joints, steering drive wheels usually provide better load capacity, stability, and floor adaptability.
No.5 Tracked Drive
A tracked AGV uses left and right tracks for movement and turns by changing the speed of each side. Because the tracks have a large contact area with the ground, they provide strong traction and good terrain adaptability. This makes them suitable for slopes, soft ground, outdoor areas, and uneven surfaces.
However, tracked systems are more complex and usually have higher rolling resistance, energy consumption, and maintenance costs. During turning, the tracks may slide sideways, which can increase track wear and damage indoor floors. For this reason, tracked drive is better suited to special environments and is not usually the first choice for warehouse AGVs.
Conclusion: How to Choose the Right AGV Drive Configuration
Differential drive is suitable for light- to medium-duty AGVs and AMRs that require a simple and cost-effective design. Horizontal steering drive wheel is a good choice for low-profile, underride, and highly flexible vehicles. Vertical steering drive is more suitable for chassis designs with limited horizontal space but enough vertical space. Mecanum wheels are suitable for omnidirectional movement on smooth indoor floors, while tracked drive is better for difficult terrain.
In actual selection, the drive type should not be considered alone. Vehicle weight, maximum payload, travel speed, chassis size, floor condition, slope, duty cycle, positioning accuracy, and budget should also be evaluated. At HKT ROBOT, our engineering team reviews these requirements and recommends a suitable steering drive wheel or differential drive solution. Send us your chassis layout and operating parameters, and we will help you select or customize the right configuration.
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Horizontal Steering Drive Wheels for Efficient and Stable AGV/AMR Operation
Differential Drive Wheels: Enhanced Performance for AGV and AMR Mobility