Motion Control

Fluidic Oscillator Array for Synchronized Oscillating Jet Generation

This technology can be used in aerospace applications, shipbuilding, gas turbines, and commercial spa equipment.NASA’s Langley Research Center develops innovative technologies to control fluid flow in ways that will ultimately result in improved performance and fuel efficiency. Often called fluidic oscillators, sweeping jet actuators, or flip flop oscillators, these flow-control devices work based on the Coanda effect. They can be embedded directly into a control surface (such as a wing or a turbine blade) and generate spatially oscillating bursts (or jets) of fluid to improve flow characteristics by enhancing lift, reducing drag, or enhancing heat transfer. Recent studies show up to a 60% performance enhancement with oscillators. NASA offers two new fluidic oscillator designs that address two key limitations of these oscillators: coupled frequency-amplitude and random oscillations. One oscillator effectively decouples the oscillation frequency from the amplitude. The other design enables synchronization of an entire array. The new oscillators have no moving parts — oscillation, decoupling, and synchronization are achieved entirely via internal flow dynamics.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling


Multiphysics CAE of a Shock Absorber

Figure 1. CAE simulation of a shock absorber. Shock absorbers are important parts of vehicles. The shock absorber is used to observe the vibrations from shock loads due to irregularities of the road surface, and operates without affecting the stability, steering, or handling of the vehicle. Generally, for light vehicles, cylindrical coil springs are used as suspension elements. The application described in this article attempts to analyze performance of a shock absorber with different suspension springs. This analysis includes comparative modeling and analysis of solid height, damping performance, oscillation capabilities of closed coil conical and cylindrical compression springs, and a suggested suitable design for improved performance.

Posted in: Application Briefs, Motion Control, Dampers and shock absorbers, Springs, CAD, CAM, and CAE, Performance tests


A Method for Accurate Load/Position Control of Rigidly Coupled Electromechanical Actuators

NASA has developed a technique designed to prevent cross-coupling in systems where two or more linear electro-mechanical actuators (EMA) are rigidly connected and are in danger of becoming cross-coupled. In such systems where the linked EMAs are commanded to achieve two distinct goals, such as position and load control, control problems often arise — especially at higher load and linear velocity levels. Both position and load control become inaccurate and in certain situations, stability of the overall system may be compromised. The NASA-developed approach mitigates the problem and achieves both accurate position following and desired load levels between the two (or more) actuators.

Posted in: Briefs, Mechanical Components, Mechanics, Positioning Equipment, Electronic control systems, Electronic equipment, Sensors and actuators


Dust Tolerant Connectors

The ruggedized housing for electrical or fluid connectors is designed to withstand harsh environments and rough handling. John F. Kennedy Space Center, Florida NASA’s Kennedy Space Center has developed a novel ruggedized housing for an electrical or fluid umbilical connector that prevents intrusion of dust, sand, dirt, mud, and moisture during field use under harsh conditions. The technology consists of a pair of hand-sized protective umbilical interface housings, each containing a connector with an integrated end cap. When the end cap covers the connector, the connector is protected. Each housing has a unique lever assembly connected to the end cap that, when squeezed, flips the end cap up to expose the connector. When in the up position, the two end caps face each other. To mate the connectors, the levers on both housings are squeezed, raising the end caps, and the two umbilicals are joined and twisted to couple them. Once the connectors are mated, the levers on both housings are released. This simultaneously seals both the umbilicals and the end caps. When dealing with cryogenic connectors, a purge can be applied to the housings to prevent icing when the connectors are demated.

Posted in: Briefs, Mechanical Components, Fluid Handling, Machinery & Automation, Connectors and terminals, Humidity, Particulate matter (PM), Seals and gaskets, Icing and ice detection


Anti-Creep Mechanism Enables Ultra-Precise Motor Table Positioning

Motion control is essential for the digitization and automation of high-tech equipment, but bearings remain basic to frictionless movement. Bearing Engineers, a bearing distributor, recently changed its name to Motion Solutions (Aliso Viejo, CA) to better reflect their evolution into a custom designer of motion solutions for high-tech electromechanical systems. Developing custom solutions has lead to developing lines of proprietary products that the company manufactures in-house.

Posted in: Application Briefs, Motion Control, Microelectromechanical devices, Suppliers, Bearings


Motion Control Challenges for Deep-Sea ROVs

Deep-sea remotely operated vehicles (ROVs) present motion control design engineers with some difficult challenges. Applications may include ROV propulsion, position thrusters, dive vanes, rudders, or robotic arms. Some problems are common to all of them.

Posted in: Application Briefs, Motion Control, X-by-wire, Autonomous vehicles, Marine vehicles and equipment


Automation System Retrofit Transforms 175-Ton Hydraulic Forming Press

Southern Manufacturing Group (SMG) of Morrison, TN, makes automotive components and industrial valves. In 2012, the automation system for its 175-ton hydraulic forming press received electrical damage resulting from a lightning strike (Figure 1). Purchasing a new hydraulic forming press would be prohibitively expensive — in the range of hundreds of thousands of dollars. Therefore, SMG needed a company that could repair the forming press in a short timeframe to maintain its production schedule.

Posted in: Application Briefs, Motion Control, Maintenance, repair, and service operations, Automation, Forming, Hydraulic equipment


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