U.S. Army Tests Modular Wheel System to Convert Any Vehicle Into a Robotic UGV.

U.S.-focused defense innovator AZAK is developing an electrically driven “wheel as a vehicle” concept that embeds propulsion, power, and control directly into each wheel for unmanned ground systems. The approach could simplify military logistics and accelerate deployment of adaptable robotic platforms for dispersed and expeditionary operations.

U.S. based company AZAK is developing an electrically driven “wheel as a vehicle” concept that departs sharply from conventional chassis-and-drivetrain architectures by treating each wheel as a complete propulsion and control unit for unmanned ground systems and other mobility applications. Rather than starting with a fixed frame, axles, and a centralized powertrain, the company has reversed the design logic, making mobility itself the foundational building block of the vehicle. This approach reflects a broader reassessment within the defense sector of how ground systems should be designed for dispersed, expeditionary, and logistics-intensive operations where adaptability and simplicity can outweigh traditional platform-centric thinking. By embedding all essential drive functions at the wheel level, AZAK is proposing a modular mobility layer that can be rapidly adapted to a wide range of military tasks without redesigning an entire vehicle from the ground up.
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AZAK's wheel-centric unmanned mobility system integrates motor, battery, and control electronics inside each wheel, enabling chassis-free platforms with high torque, low center of gravity, rapid assembly, and strong off-road performance for logistics, casualty evacuation, and autonomous ground missions (Picture source: AZAK).

At the center of the approach is the S26 wheel module, engineered as a fully self-contained propulsion node. Each wheel integrates the electric motor, motor controller, gearbox, a proprietary control system, battery management system, and the battery itself. The decision to package these components not only inside the wheel but fixed below the wheel’s center point is a deliberate design choice intended to maintain a consistently low center of gravity regardless of what structure or payload is mounted above the wheels. In practical terms, this directly affects vehicle stability, traction, and controllability when operating over uneven ground, rubble, or steep gradients.

From a technical standpoint, the published S26 Gen 1 characteristics describe a wheel measuring roughly 26 inches in height and 8 inches in width, with a mass of about 86 pounds. The system is rated for constant torque in the region of 147 pound-feet and a sprint speed of approximately 12 miles per hour. AZAK documentation also emphasizes military-relevant handling features, including an installation or replacement time of only a few seconds per wheel, IP67 environmental sealing, and support for wireless, tethered, or autonomous control modes. Range is presented as mission-dependent, with figures typically cited between 20 and 50 miles, supported by a battery capacity of approximately 1.27 kWh per wheel and a charge time on the order of 1.5 hours.

The operational implication of this design is significant. If propulsion, braking, steering logic, and energy storage all reside within the wheels, the “vehicle” becomes whatever structure the mission demands. A simple frame, a casualty litter, a cargo pallet carrier, a sensor platform, or a launcher mount can all be rapidly turned into a mobile system without integrating axles, driveshafts, or centralized powertrains. AZAK promotes a quick-connect philosophy that allows wheels to be attached to almost any object or lightweight structure, shifting vehicle development from a complex mechanical engineering effort to a faster, more modular fabrication process. For tactical units, this aligns with growing demand for adaptable robotic mobility rather than single-purpose unmanned ground vehicles.

Mobility performance is central to AZAK’s claims. The wheel-centric configuration is designed to deliver high torque directly at the contact patch, combined with inherent stability from the low-mounted mass. The company has highlighted obstacle-climbing performance well beyond the height of the vehicle frame itself and the ability to negotiate extreme gradients while carrying substantial loads. If validated under operational testing, this addresses a persistent weakness of many small UGVs, which often struggle when transitioning from roads to steep, broken, or debris-strewn terrain under load.

Product development has followed a steady trajectory rather than a rapid commercial launch. AZAK indicates it has self-funded in-wheel technology development since the mid-2010s, gradually refining the design through prototypes oriented toward defense and security use cases. Government innovation programs in the United States have shown interest in the concept, particularly in relation to contested logistics and rapid deployment scenarios. One focus area has been lightweight, low-signature platforms capable of hauling equipment or evacuating casualties in dispersed operations, where silence, reliability, and ease of repair are more valuable than speed or armor. The distributed nature of the wheel system is also presented as a survivability feature, since multiple wheels would need to be disabled to fully immobilize a platform.

AZAK’s approach matters because it challenges long-standing assumptions about how military ground vehicles must be built. By decoupling mobility from heavy mechanical drivetrains and bespoke hulls, a standardized powered wheel could enable families of mission-specific platforms at lower cost, with simplified logistics and maintenance. Damaged systems could potentially be restored by swapping a wheel rather than repairing a drivetrain in the field. At the same time, the architecture introduces trade-offs that defense users will examine closely, including thermal management inside sealed wheels, vulnerability of distributed batteries, electromagnetic and cyber resilience of wheel-level controls, and the dynamic effects of concentrating mass at the wheel in extreme terrain. Whether AZAK’s concept ultimately reshapes the defense ground mobility sector will depend less on its novelty than on how convincingly it performs under rigorous military testing and integration with autonomous control systems in realistic operational environments.