In common systems, sensors sense input stimuli and convert them into digital signals. Microcontrollers receive these signals and compute output based on certain logic. Actuators generate the desired output based on these calculations. The most sophisticated actuation systems, however, have coupled sensing and actuation through material computation. These so-called “whippany” actuators combine a microcontroller with an IPMC, or inorganic semiconductor, to perform sensing and actuation. In addition to reducing the size and weight of the actuation system, they also offer high performance and are robust against vibration and shocks.
The control surface actuators on the wings and tail of commercial aircraft are controlled using FBW, or fly-by-wire. FBW allows for more precise and rapid control of the aircraft. However, these systems can be complicated and difficult to operate, especially under varying conditions. This is because actuation systems must be able to provide a large range of responses to different inputs, ranging from low-amplitude to high-frequency.
To satisfy these demands, actuators must have a wide frequency response, and low phase lag. The latter criterion refers to the actuator’s ability to track its command at very small input amplitude, and the former involves the ability to meet a specified maximum rate capability at a given external load, i.e. the rate at which the actuator’s main ram can open its valve ports to full extent. These parameters are determined primarily by the actuator manufacturer, with considerations to the piston area, orifice size, cross-piston leakage, and other factors that affect performance under steady loads.
The actuation system must also be capable of maintaining the actuator’s 50% closed position under changing operating conditions, i.e., during a thrust shift. This is achieved by incorporating a magneto-resistive sensor that detects the actuator’s actual position. If the commanded position is not achieved, the ECU (electronic control unit) will apply a null current to maintain the desired position.
Despite the challenges of designing and manufacturing complex actuation systems, these innovations in technology are making them increasingly popular with aircraft manufacturers worldwide. Whether these systems are used for flight control or utility motion, they enable aircraft to fly higher, faster, and farther than ever before.
Learn More About Whippany Actuation Systems
When demand increased for their electromechanical actuation systems, New Jersey-based company Whippany Actuation Systems needed to either sink a large investment into a new CNC machine or introduce automation. They chose the latter option, deciding to partner with Universal Robots to program an automated system to tend their CNC machine and create their customized adaptive grippers.
This article was written by Phil De Mauro, Manager of Manufacturing Engineering at Whippany Actuation Systems, and originally appeared on the Universal Robots Blog.
This story was originally published on March 14, 2019.
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