Let’s start with the basics. Motion controllers are special devices that control the engine operating modes. In other words, it’s the brain of every motion control system. As such, its task is telling the motor what to do based on the desired production outcome.

In fact, a motion controller contains the movement profiles and the target positions for the application, and creates the trajectories that the engine must perform to satisfy the commands. Motion control is often a closed circuit, so controllers monitor the actual path and corrects positioning or speed errors.

How do motion controllers work?

In feedback-based systems, motion controllers take an input command sent by the user, compare it with a feedback signal from the motor and apply corrective actions so that the desired input/position and actual output/position match with little – or zero – margin of error.

When creating trajectories for the motor (and/or actuator), the motion controller generates motion profiles. These are the sequences of position commands in relation to time that indicate to the motor where and how fast to place a load. Finally, the motion controller uses the trajectories created to generate the correct torque commands, which are then sent to the drive.

What Are the Components of Motion Control?

The term “motion control” doesn’t describe a particular component or part. Rather, it describes a group of individual components that all work together to create controlled movement in a machine. Some of the major parts include:

Controller – The controller is just that – an electronic device that serves as the “brain” of a motion control system that controls the motors and drives. The number of controllers used in a particular application, such as in a production line, will vary based on the number of individual processes that need to be controlled. For a complex system, there could be numerous controllers. Each of these controllers has the ability to receive instructions from, and provide feedback to, the main computer that controls the entire production line.

Motor Drive – The motor drive serves as a middle-man of sorts between the controller and motor. It interprets the signal from the controller and then supplies the correct level of power to the motor to achieve the desired motion result.

Motor – Motors used in motion control systems can take many forms and have many different applications. Their main function, though, is to receive inputs from the motor drive and convert these inputs into motion. Some types of motors typically used in motion control systems include:

Stepper – Stepper motors tend to operate in a similar fashion to regular electric motors. However, due to the specific arrangement of magnets inside of them, each shaft rotation is able to be broken down into individual “steps”. An average stepper motor might have 200 steps of 1.8 degrees each per shaft rotation. This allows for highly accurate positioning of production line components.

Servo – A servo motor provides a very accurate and powerful way to control angular motion.

Linear Actuator – Linear actuators convert the rotational motion of a motor into linear motion similar to a pneumatic cylinder.

These three main components, along with subsidiary components such as sensors and cabling, are the bulk of modern motion control systems.