How Does Motion Control Work?

As machine automation enters an era of technological advancement and rapid changes, businesses realize their capacity for lowering operating costs and improving production efficiency, which inevitably boosts business bottom line.

An essential sub-category in machine automation is motion control. The system features a range of components for controlling motion sequences, while providing precise control over speed, position, and torque.

To learn more about the critical role it plays in robotics and automated systems, let us delve into the world of the motion controller.

What is a motion controller?

Motion controllers are devices used in controlling motor operation, making them the brains behind every motion control system out there. The controller tells the motors what they should do based on the required outcome.

Types of  motion controller

There are three significant categories of motion controllers:

1. Stand-alone controllers

These units are DIN-Rail and panel-mounted. They offer interfaces for stepper drives, servo drives, and Fieldbus-based drives.

The controllers have integrated analog and digital outputs and inputs, serial interfaces for operator and programming panels, and various expansion modules and daughter boards for adding more control over machines using minimal external parts.

In many instances, a stand-alone unit can drive multi-axis machines and auxiliary equipment.

The modular design of these controllers allows users to tailor them to their specific requirements using new modules, should any needs change – essentially making the system future proof.

The incorporated CANbus interface provides for analog or digital input and output expansion. Included software programs allow stand-alone controllers to work seamlessly with hardware, delivering improved system performance.

2. PC-based controllers

These motion controllers provide network communication, high reliability and improved control functions in a single, cost-effective platform.

The controllers contain:

  • Programmable Automation Controllers (PACs)
  • Motion control cards
  • EtherCAT and DMCNET networking for rapid connectivity to servo motors, remote digital analog and I/O modules, linear motors and stepping motors

A PC-based motion controller provides high precision and response control for flexible operation and automation in high-performance multi-axis and synchronous motion control applications.

Simple wiring and fast installation ensure less integration effort.

PC control software provides Fieldbus verification and all parameters required for easy configuration of Fieldbus communication and hardware systems.

3. Individual microcontrollers

These units contain printed circuit boards with driver inputs and outputs for controlling motors and are about the size of a Raspberry. Microcontrollers make it easy to add modern features to a production line without affecting legacy equipment, while allowing businesses to leverage the Industrial Internet of Things (IIoT) with less commitment.

Microcontrollers are inexpensive and provide designers with chip-level access for project customization.

Functionalities of a motion controller

An automation controller contains movement profiles and target positions for an application.

Further, controllers also create trajectories that motors follow to fulfill specific commands. The controllers achieve this by outputting a signal to servo motors, direction and step pulses to stepper motors, or even an electromechanical conductor to switch motor circuits.

Motion controllers are often in a closed circuit, so they can monitor the actual path and correct any speed or position errors.

Effects of motion controllers

The motion controller you choose can have lasting effects on your projects.

Insufficient computing capabilities or power levels that fail your design’s requirements can degrade the unit’s abilities and performance. Conversely, an overly robust or powerful controller adds an unnecessary cost to your project.

The right controllers bring the following benefits to your project:

  • Provide smooth movement while boosting productivity
  • Are cost-effective and generate greater position and speed accuracy
  • Supply consistency to your automated projects

Features of a motion control system

Choosing the right controller for a project is as easy as looking into the following features:

  • The number of axes, which is related to the motor outputs required
  • The time interval between updates
  • A controller’s ability to provide motion for multiple axes
  • Digital to Analog (D/A) resolution

Controllers fall in one of these ranges, depending on capability and complexity:

  • For simple control. Indexing systems provide simple velocity or position control, and primarily have very limited (or no) acceleration control, limiting acceleration and speeds. These systems usually employ motors with an integrated drive and controller. An indexer features a microprocessor with limited coding, which is suitable for hobbyists, thanks to easily accessible open-source software.
  • Full-fledged motion control system. These controllers are capable of operating high-speed motors and provide multiple ways to adjust speed. They have outputs and inputs for monitoring emergency stops, homing, end of travel limit, and other safety features. I/O ports also offer machine-control logic in addition to multi-axis control, pre-buffered movement, positional offsets, and other advanced features.


The motion controller is a central component of any motion system. Selecting the right controller for system architecture determines the machine or automated system performance. Now that you understand the role a controller plays in the production system, it’s time to get creative.

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