Motion Control

Advantages of Servo Motor and Direct Drive Technology

For many years, stepper motors have been the most popular type of electric motor designed into instrumentation for a wide variety of reasons. Stepper motors have become increasingly commoditized, and can be sourced easily. In addition, the growing “maker movement” has simultaneously made them more popular and reduced their cost. Unlike servo motors, stepper motors don’t require tuning to optimize their performance. What’s more, scaling and motion commands are typically quick and simple to execute using stepper motors. Servo motors often require a bit more expertise in executing complicated (torque, velocity, or position) loop closures. Finally, micro-stepping allows most modern drive electronics to step or increment a stepper motor to a resolution of 50,800 steps per revolution or higher.

Posted in: Articles, Motion Control, Motors & Drives

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An Inside Look at Electromechanical Power-Off Braking Options

Making the right choice between spring set and permanent magnet brakes can impact safety, durability, maintenance, and performance. Power-off brakes are designed to hold or stop motion in the absence of power. Adding an electrical current releases the brake, freeing the load for motion. Given the safety ramifications of keeping a system locked in place until it is powered up, motion control system designers tend to specify power-off brakes more often than power-on brakes. There are, however, two different failsafe brake technologies: one uses compression springs to hold its load in place, and the other uses permanent magnets. Each has specific strengths and weaknesses, and knowing the difference can impact safety, durability, cost, and performance.

Posted in: Articles, Motion Control

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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

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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

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A Soft Control Architecture: Breakthrough in Hard Real-Time Design for Complex Systems

How to cut costs, improve quality, and differentiate your products with a software-based approach to machine automation OEMs have long relied on expensive, cumbersome hardware like FPGAs and DSPs for precision motion control. But new advances in software-based machine automation are changing that paradigm, with huge potential benefits.

Posted in: White Papers, Electronics & Computers, Manufacturing & Prototyping, Motion Control, Machinery & Automation, Robotics, Semiconductors & ICs, Software

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5 Real-Time, Ethernet-Based Fieldbuses Compared

Ethernet-based fieldbus standards have changed the game for machine builders. But with so many protocols competing to be most valuable and viable, how should you decide which to use?

Posted in: White Papers, Electronics & Computers, Motion Control, Machinery & Automation, Robotics, Software

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Software vs Hardware Machine Control: Cost and Performance Compared

OEMs traditionally used DSP-based hardware, plugged into a PC, for motion control. But new software-based solutions have challenged this approach, claiming equal or better performance at lower cost.

Posted in: White Papers, Manufacturing & Prototyping, Motion Control, Machinery & Automation, Robotics

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