Motion Control

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

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

Embedded Virtualization Enables Highly Integrated “Soft Motion” Platforms on the PC

With the increased processing power that PCs have attained, a complex machine that used to require an expensive and dedicated hardware-based motion control solution can now be accomplished on a multicore PC running on a real-time operating system (RTOS).

Posted in: Application Briefs, Motion Control, Computer software and hardware

Service Robots Use Flat Motors to Provide Reliable, Safe Motion

Unlike industrial robots for manufacturing, service robots come with their own specification requirements aimed specifically at the end user, and the most discriminating user at that — a human being. That’s why designing and manufacturing service robots takes a particular set of skills and engineering expertise.

Posted in: Application Briefs, Motion Control, Electronic control systems, Robotics

Encoders Ensure Position Accuracy of Linear-Torsion Tester

Instron (Norwood, MA) manufactures materials testing equipment and accessories that are used to test samples ranging from components for jet engines to medical syringes. The company’s ElectroPuls systems are used for fatigue testing, which examines the behavior of materials under fluctuating or cyclic loads in the elastic regime. The E1000, E3000, and E10000 fatigue test systems are suited for biomedical/biomechanical research applications, and feature a wide dynamic performance range and low force characteristics. The all-electric systems use linear motor technology to eliminate the need for ball/lead-screws, and enable slow-speed static tests through to high-frequency dynamic tests at over 100 Hz.

Posted in: Application Briefs, Motion Control, Automation, Test equipment and instrumentation

Motion Solutions for Electric Expansion Valves

Expansion valves are flow-restricting devices present in any refrigeration system. The valve needle remains open during steady state of operation. The size of the opening, or position of the needle, is related to the pressure and temperature of the evaporator. When set and controlled properly, an expansion valve will keep the evaporator active throughout its operation.

Posted in: Application Briefs, Motion Control, Thermal management, Cooling

Hamburg Airport Relies on Drive Technology to Keep Bags Moving

Hamburg Airport in Germany handles nine million pieces of baggage every year. For the baggage handling staff, the reliability of the conveyor system and the prevention of faults are the highest priorities. The breakdown of even a single component of the system would result in a backlog and unacceptable delays.

Posted in: Application Briefs, Motion Control, Ground support

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