By Tom Quartararo, Mechatronics Engineer
Integrated actuators are quickly becoming the preferred solution for a majority of industries including industrial automation, unmanned vehicles, and laboratory applications for reasons including higher reliability, ease of use, and cost/space savings. The recent advances in microcontrollers and digital signal processing have enabled manufacturers to build highly capable motor control electronics directly into actuator housings making for compact and tidy motion control solutions. Integrated control electronics eliminate the additional cable management, space/mass, and learning curves that come with external control electronics while decreasing costs and complexity for the end-user.
Brushless DC motors offer superior performance characteristics and reliability compared to their brushed DC counterparts, but have the downside of requiring more advanced control electronics. Field-Oriented Control (FOC) is a commutation method that offer the best BLDC motor performance, but implementation requires complex and high-speed control algorithms. FOC provides very high efficiency at both slow and fast rotational speeds, extremely smooth motion even at very slow speeds, excellent acceleration capability, and control over the motor’s phase currents. Abstracting this control complexity away from the user by directly integrating the FOC drive electronics into the actuator provides users with best-in-class performance in a simple to use, robust, and economic solution.
Ultra Motion’s Servo Cylinder has built-in brushless DC motor control electronics with Field-Oriented Control, and our high-resolution Phase Index absolute position feedback that eliminates homing and provides high reliability feedback throughout the actuator’s stroke. Phase Index is Ultra Motion’s patented contactless absolute position sensor that is seamlessly integrated with the Servo Cylinder’s controller and is the heart of the motion control system. Phase Index has proven itself extremely reliable in a range of harsh environmental conditions including temperature extremes and especially high shock/vibration applications. Our sensor does not have wear concerns like those seen with potentiometers, requires no battery backup to maintain absolute position, and is inherently resistant to electrical noise.
Ultra Motion actuators are designed to provide reliable operation in the most adverse environmental conditions possible. The Servo Cylinder can withstand 24/7 exposure to the elements, constant bombardment by waves in unmanned surface vehicles, harsh industrial environments, and has even been used for thrust vector control of small rocket engines. The Phase Index architecture makes for a mechanically robust sensor that is capable of withstanding extreme shock and vibration environments without issue. This is in contrast to linear potentiometers or LVDTs that are susceptible to vibration, wear, and take up larger volumes.
A variety of communication protocols are available in order to suit the needs of many different industries. The Servo Cylinder supports RS-232 and RS-422 serial protocols, RC PWM, 4-20 mA in/out, CANopen, CAN, and more. The large range of supported protocols ensures simple integration with PLCs, LabVIEW/MATLAB, autopilots, and simple Python or C programs. Detailed telemetry can be broadcast to the user for real-time information regarding actuator health. Telemetry options includes actuator position, temperature, bus voltage, phase currents which are proportional to force, relative humidity within the enclosure, total stroke over the life of the actuator, etc. This data can be used for process monitoring, preventative maintenance, and to detect potential failures before being launched into the field.
Users no longer have to deal with the hassle of external controllers and sourcing multiple components from multiple vendors for their actuation needs. Robust electromechanical actuators with state-of-the-art control electronics and absolute position feedback are available that offer all of the advantages of EMAs with a streamlined user experience.
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