One way to improve servo system performance is to increase the gains in the control loop, allowing the system to respond faster to commands and to settle more quickly, with less oscillation. But increasing the servo gains means that any resonances in the system — typically due to mechanical compliance — are further amplified, which can […]
What is external device monitoring and how does it relate to machine safety?
According to the Machinery Directive 2006/42/EC, technical protective measures should be used to reduce risks that cannot be avoided through safe design measures. These technical protective measures include safety devices such as door locks, covers, light curtains, and other equipment that monitors the machine movements. When the safety device controls and external device, such as […]
What machine safety functions address speed, and when are they used?
The Machinery Directive 2006/42/EC states that when a machine manufacturer is unable to eliminate the risks of potential hazardous situations (for example, mechanical hazards such as crushing or cutting) through safe design methods, the next step is to reduce the risks through technical protective measures. These technical measures include protective devices, such as door locks […]
What is Machine as a Service (MaaS) and what are its benefits?
Most of us are familiar with the software as a service (SaaS) business model, in which users pay a fee to access software over the internet, without requiring an application or download to a local machine. The software as a service model made complex software, such as CRM (customer relationship management) systems, more accessible to […]
What are digital twins and how are they used in industrial manufacturing?
Manufacturing even the simplest product requires expertise in materials, equipment, operations, and process flow. And the interdependencies of these elements make it extremely difficult — if not impossible — to “get it right the first time” when setting up a new manufacturing line or modifying an existing process. Every element, from the product design to the […]
How to calculate retaining ring maximum speed (rpm), and when it matters
Selecting an appropriate retaining ring for an application typically involves evaluating factors such as installation stress, the radial load exerted by the ring, and the thrust capacity of the ring. And because the groove that holds the ring is integral to the ring’s performance, groove deformation needs to be considered as well. But when an external […]
What are latency and jitter and why are they important to industrial networks?
Applications that use closed-loop control often require communication networks that provide deterministic, real-time control of data transmission. This means the network guarantees that a message will be transmitted, or an event will be responded to, in a specified, predictable period of time — not faster or slower (deterministic) — and that the message will be transmitted […]
When is motor output power a useful specification and how is it calculated?
In motion applications, motors are typically chosen based on their torque and speed capabilities, using a torque-speed curve that describes the motor’s performance when paired with a specific type of drive and operated under specific conditions. But motors can also be rated, or specified, by their output power. Here, we’ll look at how output power […]
Motion system design: How to manage inertia mismatch
One of the most important parameters when sizing a motion system is the inertia of the load being moved. Regardless of the type of motor being used — AC induction, stepper, brushless DC, or AC servo — the ratio of the load inertia to the motor inertia has an important influence on system performance. If the […]
What does embedded mean in the context of motion control?
Over the past several years, embedded solutions have found their way into the motion control space, with terms such as embedded motion, embedded motion control, and embedded motion controller commonly used in product descriptions and technical articles. Although there are no standard definitions for these terms, they all refer to some level of integration of […]
Why do stepper motors vibrate and what are ways to avoid or dampen vibrations?
With each discrete step that a stepper motor makes, the inertia of the system causes the motor to slightly overshoot (or undershoot) the intended step angle. The motor then oscillates, or “rings,” until it finally settles at the commanded position. If the frequency of these step-by-step oscillations is at or near the motor’s natural frequency, […]
When is the application of overvoltage safe (and common) for stepper motors?
For most types of motors, operating with a supply voltage that is higher than the rated voltage — referred to as overvoltage — can cause an increase in current, and heat, high enough to damage the coils and other motor components. But in some cases, a stepper motor can be operated at a voltage higher than rated […]
Which types of DC motors can be used as servo motors? (And a refresher on DC motor technologies)
Servo motors are used in applications where precise control of position, speed, or torque is required. But many different types of motors can be considered servo motors — the defining feature of a servo motor is that it incorporates or reads feedback in a closed-loop system. In fact, although many servo applications use synchronous AC motors, […]
The top 10 motion control articles of 2021
We cover a wide variety of topics here at motioncontroltips.com — from Industrial Ethernet and networking to springs and shock absorbers. So, naturally, our most-read articles typically span a wide range of subjects. But 2021 was a bit different, with all but one article being related to motors, and more than half of the articles […]
What determines worm gear efficiency, and is it really that low?
Worm gears are often used for their ability to provide very high reduction ratios (and high torque multiplication) in a compact, single-stage design. But traditional thinking says that these benefits come at the expense of efficiency. Here, we’ll look at the factors that determine worm gear efficiency and how to get the benefits they provide […]
What is cyclic synchronous control (position, velocity, and torque)?
Cyclic synchronous control modes — cyclic synchronous position, cyclic synchronous velocity, and cyclic synchronous torque — are standardized operation modes of drives, defined in the CiA 402 profile specification, CANopen device profile for drives and motion control and included in the IEC 61800-7 standard, Adjustable speed electrical power drive systems — Part 7: Generic interface and use of […]
Why is RMS current important in stepper motor applications?
Most precision stepper motor applications — especially those in automation and motion control — use a control method referred to as microstepping, which creates a sinusoidal (or nearly sinusoidal) current waveform, rather than the square wave of current produced with typical full-step control. The current rating of a stepper motor depends on the amount of […]
What is the CANopen over EtherCAT (CoE) protocol?
The CANopen over EtherCAT (CoE) protocol allows devices equipped with CANopen to be used on EtherCAT-based Industrial Ethernet networks. CANopen: Simple and low-cost CANopen is a communication protocol based on the CAN (Controller Area Network) physical communication standard. In the OSI communication model, CAN specifies the physical and data link layers, while CANopen addresses the […]
How do wave springs eliminate problems associated with traditional coil springs?
Coil springs and wave springs are both types of compression springs, meaning the spring’s force increases as its axial length decreases (as the spring is compressed). But coil springs and wave springs react differently to applied loads, especially in terms of how stresses are created in the material, which in turn, affects their working load […]
What are interferometric laser encoders and where are they used?
Optical encoders such as glass scales are often used for linear position measurements that require micron-level resolution. But applications in industries such as semiconductor and aerospace — especially those that involve optics — require measuring capabilities in the nanometer and even picometer ranges, beyond the resolution of most scale-based optical encoders. For these applications, direct, non-contact […]
How do manufacturers address cogging in linear motors?
Iron core linear motors are known for their high continuous and peak force capabilities, good thermal management, and excellent force-to-size ratio. But they’re also known to produce cogging forces, which lead to force ripple, or variation in output force. But how much of a problem is cogging for iron core linear motors, and what are […]
What are recipes in the context of HMIs?
Many companies offer a range of products that are variations of a “base” model, using many of the same components, manufacturing methods, and processing steps to keep inventory and manufacturing costs under control while still providing customers with a range of choices to fit their exact needs. Automobiles are an excellent example. Take the Ford […]
ATEX and IECEx classifications and markings explained
When electrical equipment is used in a potentially hazardous location — one that contains flammable gases, vapors, liquids, dust, or fibers — it’s important that the potential for fire or explosion be minimized. One way to do this is to use equipment that has been certified as suitable for that environment and not likely to […]
What are harmonics and how do they affect motion control systems?
Harmonics are voltages or currents caused by non-linear loads on a power supply. Harmonic frequencies occur at integer multiples of a fundamental frequency and are superimposed on the fundamental voltage or current waveform, creating a distorted waveform. Harmonics are classified first by their order, or the integer multiple of the fundamental frequency. For example, for […]
Classifying hazardous locations: What’s the difference between Class, Division, and Zone?
According to the National Fire Protection Association, a hazardous location is an area where fire or explosion hazards may exist due to electrical equipment operating in the presence of flammable or ignitable gases, liquids, or vapors, or in the presence of combustible dust, fibers, or flyings. But even within this definition, the risk of fire or […]