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COTS servo drive is tough enough for military use

Edited by the Engineeringtalk editorial team Feb 28, 2008

Hardened drives provide networking and stand-alone motion control for brush and brushless motors, and direct drive linear motors and actuators.

Copley Controls has developed a hardened version of its versatile panel-mounting Accelnet servo drive to meet both military and extreme industrial environments.

The drive's extended temperature, humidity, vibration and shock ranges provide added security in nonextreme applications.

Designated Series R20, the hardened drives provide networking and stand-alone motion control for brush and brushless motors, and direct drive linear motors and actuators.

R20 drives deliver up to 3.2kW peak power, are available for operating voltages of 55, 90 and 180V, and deliver 9, 18 and 36A peak currents.

R20 drives operate in stand-alone and networked operating modes.

Their very wide span of command, encoder feedback and communications interfaces allow users to put a single drive model to work in widely differing motion control systems.

Control modes include indexing, point-to-point, PVT (position, velocity and torque control), as well as electronic camming and gearing.

Specific command interfaces include CANopen, DeviceNet, ASC11/Discrete I/O, stepper, +/-10V position/velocity/torque and PWM velocity/torque command.

This communications flexibility highlights the drive's compatibility with so many different motion control architectures.

Copley's CME 2 setup software enables drive users to automate otherwise time-consuming system setup and commissioning functions.

The software provides auto tuning of the amplifier's current loop, and auto phasing of Hall sensors for both rotary and linear motors and actuators.

With setup and tuning completed, the user stores software settings in the drive's nonvolatile Flash memory.

Copley has developed extensive libraries of motion control software (Copley Motion Libraries) and software COM objects to make system development fast and simple.

The development of low level code to control a CANopen network of intelligent drives is eliminated.

All network housekeeping is taken care of automatically by a few simple commands linked into the user's Visual Basic, LabView or C++ application program.

The R20 drives use the advanced carrier cancellation modulation (CCM) for zero crossing linearity and low ripple current.

Ripple frequency is 30kHz.

Current loop bandwidth is 2.5kHz.

The amplifier provides 15kHz current loop update rate (67us) and 3kHz (333us) position and velocity loop update rate.

R20 drives are housed in shielded enclosures measuring 168 x 99 x 30mm.

The drives are protected against overcurrent, overtemperature and incorrect operating voltages.

They are further protected from short circuits between outputs and from output to ground.

In addition, protection circuits guard against loss of signal from either the encoder or the motor's Hall sensors.

Built-in computation algorithms monitor the heating effect of load current, enable a motor to run safely at its outer performance envelope.

Hardening the Accelnet R20 drive for COTS military, aviation and marine applications also creates a motion control solution for extreme industrial environments.

R20 drives handle the high temperatures of solar energy collection, food manufacturing, oil refinery and steel foundry uses, plus the opposite extremes of arctic satellite tracking, industrial cold rooms, and refrigerated meat packing operations.

Model R20 also qualifies for oil rig use, ship-board cargo handling equipment, and off-road vehicles, where resistance to shock and vibration are critical.