Servo drivers help weapons platform take accurate aim

The vehicle-mounted T-360 uses vehicle power to operate the AllMotion EZSV23 controller/drivers used for azimuth and elevation control of weapons.

By Michael Jermann, Assistant Editor

Precision Remotes designs and manufactures a line of on-the-move, accurate firing weapons for military and commercial use suitable for weight constrained vehicles. The T-360 weapons platform is Precision Remotes’ main pan and tilt product and is incorporated in each of its platforms, including the T-360FS, the facility security platform. The weapons platform accommodates 5.56 mm (600 rounds) and 7.62 mm (400 rounds) weapons and fits into the NATO standard 2.5-in. ring mount receptacle. The unit operates at only 170 W, provides full motion, and can be installed or removed in less than five minutes using no tools, and reverts to manual operation in seconds.

The T-360 was designed to provide a full 360º-azimuth movement. To do this the company needed fully integrated controllers that required little to no tuning when connected to most motors. As with other equipment to be used outside and in the elements, the stabilization unit required the use of controllers that were robust and stable.

Precision Remotes selected three AllMotion EZSV23 servo drives for the system for the control of the azimuth and elevation functions. The EZSV23 allows fast and easy implementation of either brush or brushless DC motors. The servo controllers’ default PID operation offered a robust and stable platform for the weapons platform’s operations. Another reason for using the EZSV23 family of products was for their large power per volume specification. Precision Remotes needed to save real estate as well as keep the weight of the T-360 system down so that it remained relatively portable. At 2.25 x 2.25 in., the controller/drivers easily fit inside the enclosures.

Commands can be issued from any serial terminal program or from the EZSV23’s Stepper Windows application.

For the azimuth function of the system, Precision Remotes selected two EZSV23 drivers that were synchronized together for ramp up and ramp down operations as well as for accurate position and end-stop control—both soft and hard stops had to be implemented. System resolution for the azimuth operation is about ±100th of a degree. The EZSV23 servo controls get their feedback from 2000 line encoders mounted directly to each motor. The azimuth function operates at the high speed of 150 degrees per second for fast and accurate response. The elevation system for the T-360 incorporates only one motor and one EZSV23 servo controller/driver. Equally as accurate as the azimuth control, the elevation moves at 90 degrees per second.

Other important features of the EZSV23s included their operation temperature range which was greater than Precision Remotes’ specs of –40ºC to 71ºC, and their very small size and weight restraints necessary to make the T-360 light-weight and compact for easy installation and removal. A single 4-wire bus (two power wires and two communications wires) was used to link to 16 motors in a daisy chain configuration. Each EZServo is also capable of standalone operation with no connection to a PC.

The entire T-360 lightweight weapons platform operates from vehicle power, which is 28 VDC. Vehicle power is bumped up to 33 VDC for the controller/drivers, which helped Precision Remotes to increase the performance of its T-360 product line. The controls themselves are rated up to 40 VDC, so they operate well within their allotted specifications. The system is built around the RS45 bus system, and uses a Game-Boy style controller for ease of operation and training.

AllMotion
www.allmotion.com