Motion Control

Oil Sheer Clutch Cuts Downtime for Metal Stamping Press

Replacing a mechanical clutch, the oil sheer technology supplies constant, reliable tension on the stock feeding a 400-ton press to deliver precision and repeatability.

In the metal stamping business, precision, repeatability, and uptime are key. But stamping accuracy suffers when improper tension on the coil feeders incorrectly supplies metal to the presses, resulting in off-spec parts and increased rejections. ART Technologies of Fairfield, OH, relies on an oil shear clutch brake to supply constant, reliable tension on the coil feeding to one of its 400-ton presses to produce the precision and repeatability it needs, with no downtime for maintenance or adjustment. When the plant is working 20 hours a day, that uptime is as critical as the tolerances it maintains.

Posted in: Application Briefs, Motion Control

Cooling Solution Helps NASA Get Closer to Mars

Cold conditioning systemAggrekoHouston,
Posted in: Application Briefs, Motion Control, Research and development, Cooling, Spacecraft

Custom Brakes Meet the Challenges of Gearless Motor Elevators

Standard braking systems could not meet the difficult speed, energy, and dynamic torque constraints.

A manufacturer of low and high-rise elevators faced a challenge when customers began calling for a flexible elevator to meet the needs of the growing mid-rise, mixed-use building market. The global construction boom of mid-rise buildings can be attributed to several factors. Developers are more apt to build “short” because it requires less capital and the time to get permits approved is reduced considerably, especially in developing countries.

Posted in: Application Briefs, Motion Control, Braking systems, Needs assessment, Product development

Evaluation Standard for Robotic Research

Universal benchmarks can standardize the measurement of robotic manipulation tasks.

The Yale-CMU-Berkeley (YCB) Object and Model Set provides universal benchmarks for labs specializing in robotic manipulation and prosthetics. About two years ago, Aaron Dollar, an associate professor of mechanical engineering and materials science at Yale University, came up with the benchmark idea to bring a level of specificity and universality to manipulation tasks in robotics research. He enlisted the help of two former colleagues in the robotics community, Dr. Siddhartha Srinivasa from Carnegie-Mellon University and Dr. Pieter Abbeel of the University of California, Berkeley.

Posted in: Briefs, Motion Control, Automation, Kinematics, Research and development, Robotics, Quality standards, Biomechanics

Mechanisms for Achieving Non-Sinusoidal Waveforms on Stirling Engines

The current state-of-the-art Stirling engines use sinusoidal piston and displacer motion to drive the thermodynamic cycle and produce power. Research performed at NASA Glenn has shown that non-sinusoidal waveforms have the potential to increase Stirling engine power density, and could possibly be used to tailor engine performance to the needs of a specific application. However, the state-of-the-art Stirling engine design uses gas springs or planar springs that are very nearly linear, resulting in a system that resonates at a single frequency. This means that imposing non-sinusoidal waveforms, consisting of multiple frequencies, requires large forces from the drive mechanism (either the alternator or the crank shaft). These large forces increase losses, and increase the size and requirements of the control system. This innovation aims to reduce the external forcing requirements by introducing internal mechanical components that provide the forces necessary to achieve the desired waveforms.

Posted in: Briefs, Mechanical Components, Mechanics, Motion Control, Alternators, Crankshafts, Engine efficiency, Stirling engines

Improving Stirling Engine Performance Through Optimized Piston and Displacer Motion

Stirling engines typically achieve high efficiency, but lack power density. Low power density prevents them from being used in many applications where internal combustion engines are viable competitors, and increases system costs in applications that require Stirling engines. This limits their operating envelope in both terrestrial and space applications. Sinusoidal piston and displacer motion is one of the causes of low power density. Previous work proposed solving this problem by replacing sinusoidal waveforms with waveforms that more closely approximate those of the ideal Stirling cycle. However, when working with real engines, imposing ideal waveforms has been shown to reduce power density and efficiency due to increased pressure drop through the regenerator and heat exchangers.

Posted in: Briefs, Fluid Handling, Mechanical Components, Mechanics, Motors & Drives, Engine efficiency, Pistons, Stirling engines

Custom Machines Create Engine Lip Skins on Boeing Aircraft

MJC Engineering, a custom machine tool builder in Huntington Beach, CA, specializes in metal-spinning machines for such applications as sheet spinning, flow forming, wheel spinning, and rotary forging. The company was commissioned to build a series of metal-spinning machines for GKN for use at its plants in Camarillo, CA and Orangeburg, SC. These machines produce lip skins for the engine housings on Boeing 777X and 737MAX aircraft. Using CNC from Siemens Industry (Elk Grove Village, IL) and robotic handling technology — in addition to its proprietary servopump-controlled Green Power™ hydraulic power unit that saves up to 40% on energy — the MJC team devised a unique solution to an engineering challenge brought to them by GKN.

Posted in: Application Briefs, Aviation, Motion Control, CAD, CAM, and CAE, Forming, Manufacturing equipment and machinery, Robotics, Commercial aircraft

Motor Controller Provides Custom Electronic Control Solution

A Fortune 200 company needed a turnkey, DC voltage, agency-compliant electronic control solution capable of providing motion control with memory position capabilities and auto run/sense features for a multi-motor application involving four motors. Particularly important to the design criteria was the development of an interactive system of wireless remote control capabilities and other user interface devices, including iPhone and iPad interconnect devices. It was a complicated job, and the company would need to partner with experts who could deliver a time- and cost-effective solution.

Posted in: Application Briefs, Motors & Drives, Stability control, Electronic control systems, Wireless communication systems, Collaboration and partnering, Electric motors

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

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.