Stepper motors have different torque-speed characteristics depending on whether the motor is starting/stopping or already running. These characteristics are depicted in two curves on the motor’s torque-speed chart, and it’s important to understand the differences between these curves and what each one means for the motor’s operation. But a stepper motor can also produce torque […]
Controls for linear axes
Boosting productivity with the right direct-drive motor and linear-motor feedback
Feedback options for linear motors and direct-drive torque motors abound. The most common employ optical, magnetic, capacitive, or inductive measurement. Here we explain how the key application parameters of precision, cost restrictions, and insensitivity to mechanical characteristics and environment dictate which technology is most suitable. By Steffen Preg | CEO • SIKO Products Inc. Machines […]
What types of motion can you create with multi-axis linear systems?
For many tasks, multi-axis linear systems — Cartesian robots, X-Y tables, and gantry systems — travel in straight lines to achieve quick point-to-point movements. But some applications, such as dispensing and cutting, require the system to follow a circular path or a complex shape that can’t be created by simple lines and arcs. Fortunately, modern […]
Stepper motor performance: Is it possible to get high torque at high speeds?
The most notable stepper motor performance characteristics are precise positioning, good holding torque, and good low-speed torque characteristics. But in some cases, application parameters necessitate high torque production at high speeds, while design or control constraints dictate the use of a stepper motor. Although stepper motors aren’t notable for their ability to produce high torque […]
Motion controller basics: What are the differences between PLCs, PACs, and IPCs?
As the “brain” of a servo system, a motion controller is responsible for ensuring the motor is following the specified motion profile and correcting any errors between the commanded value (in terms of position, speed, or torque) and the motor’s actual value. The motion controller also handles other supervisory and processing tasks, such as ensuring […]
What’s the difference between a servo drive and a motion controller?
Servo systems are made up of four key parts: a motor, a feedback device, a servo drive, and a motion controller. The servo drive and motion controller work together (supported by information from the feedback device) to provide the correct power to the motor so that it executes the intended movement or produces the desired […]
How to use a torque-speed curve to select a servo motor
Servo motors are typically used for dynamic applications, where quick acceleration rates necessitate high torque production. In fact, one of the defining characteristics of a servo system is its ability to precisely control torque across a wide speed range, and the various speeds and torques required during the application’s move profile are a key parameter […]
When should you use microstepping control for stepper motors?
Stepper motor operation is relatively straightforward. The drive sends pulses of current to the motor, and each pulse advances the motor by one step, or fraction of a revolution. The amount of movement per current pulse depends on the design of the stator and rotor. For permanent magnet stepper motors, a full step angle of […]
What is servo tuning and why is it important?
Unlike stepper motors, which rely on even pulses of current to turn the motor in discreet steps, servo motors operate with continuous current to reach a specified position, velocity, or torque. The precise amount of current to be delivered to the motor is determined by the servo controller, based on information supplied by an encoder […]
How does closed-loop stepper control work … and why not just use a servo?
Stepper motors are inherently open-loop devices. They don’t require feedback because each pulse of current delivered by the drive equals one step of the motor (or a fraction of a step in the case of microstepping). Plus with small step sizes (or step angles) the motor’s position can be determined very precisely without the need […]
