Armored Fighting Vehicles (AFVs) play a critical role—keeping soldiers safe while achieving mission objectives. When a defense contractor sought to upgrade its first-generation AFV with electromechanical subsystems, the company turned to Elmo Motion Control for a unique set of servo drive and controller capabilities that met the high-performance requirements of the multi-functional defense system.

Read this case study to learn about:

  • How a combination of servo drives and a controller power a multi-functional defense system
  • Achieving precise and reliable motion in high-shock, high-vibration machines
  • Remote control via highly intelligent Wi-Fi application


The Armored Fighting Vehicle (AFV) is a multi-functional defense system that combines operational mobility with offensive and defensive capabilities. These ultra-rugged, reliable vehicles are designed to achieve mission objectives while protecting the soldiers they carry.

When a defense contractor sought to upgrade its first-generation AFV with electromechanical subsystems, the company turned to Elmo Motion Control for support.

Machine requirements

The AFV carries two critical weapons systems: a turret-mounted machine gun and a portable antimissile launcher. Its support systems include night vision and radar and a rear door functions as a ramp for personnel entry and exit. Other essential capabilities include power vehicle control (braking, acceleration, and steering) with a remote option. The company wanted to use servo systems to position the turret and machine gun, aim the antimissile launcher, and to control the rear door ramp. They also wanted to upgrade the vehicle control system and convert the life-support system to electromechanical technology.

The application presented numerous challenges, including tight weight restrictions and limited space in the control cabinet. The weapons systems and rear door are high-inertia systems that require strict precision and repeatability, so the servo axes needed to provide high torque output. However, the portable nature of the AFV limits both the size and power consumption of the electronics. Meanwhile, the electronics must be rugged enough to survive prolonged exposure to harsh conditions, including high shock and vibration, extreme temperatures, and contamination.

Motion control solution

For the machine gun, the team chose the ExtrlQ Gold Eagle, an ultra-high current/low voltage servo drive that generates up to 650A of continuous current, allowing it to respond to feedback from high-resolution encoders and accurately track the target. The drive operates with 99% efficiency, maximizing battery life. When the gun fires, it can generate recoil shock loads as high as 70 G, which the ExtrIQ drives can tolerate, as they are ruggedized for extreme environments.

For the anti-missile launcher, the team chose the Gold Solo Hornet, a standalone intelligent servo drive that eliminates the need for a multi-axis controller. Each unit can control two brushed motors, and the drives use sensor-less feedback to control speed, torque and position without an encoder, reducing size, weight and cost. They incorporate Smart Drive Technology, enabling the drive to analyze system response to motion commands. Using filtering algorithms, the drive adjusts the output signal to prevent it from exciting resonances, avoiding overshoot and reducing settling time.

The ExtrlQ Gold Solo Double Bee, a high-power-density (160A/80VDC), extremely compact drive, proved a good fit for the rear door ramp subsystem. A ruggedized drive, it can tolerate the shock and vibration of the door and can operate in Torque-Limited Position Mode, protecting the axes by allowing the door position to change if the current exceeds a threshold. The door is maintained in servo mode without using brakes, and the regenerative energy is channeled back to the drive, where it is stored in a capacitor to extend battery life.

For remote steering control, Elmo assisted the customer in building a subsystem based on its ExtrlQ Platinum Lion Multi Axis Controller. Together with the Elmo Application Studio (EAS), the controller modifies nonlinear responses in real time, smoothing the performance of the AFV. To enable the emergency takeover feature, three Gold Bee drives deliver the power density and current resolution required for steering actuation. The Platinum Lion uses built-in Ethernet/IP networking to interface with the drives and communicates with a remote operator via Wi-Fi. This complex solution was implemented onsite in just two weeks.

Elmo ran the condenser blower with a Gold Solo Bee 80A/80VDC and the compressor with a Double Gold Bee 160A/80VDC. To maximize the efficiency of the air conditioning blower, the team chose a Gold Bee 80A/80VDC operated in inverter mode. With its extended I/O support, the Platinum Lion Multi-Axis Controller manages the various sensors, enabling a single unit to manage the entire system.

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