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 […]
FAQs + basics
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, […]
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 […]