How Mathematics & Physics are Used in Motion Control

How Mathematics & Physics are Used in Motion Control

December 21, 2022

When we consider the sophisticated machinery that’s used in the manufacturing sector, several things come to mind. The first, is that the machinery needs to be able to perform tasks consistently, efficiently, and above all, safely. While all three of these things must be achieved before the equipment can be sold, none of them can be done without two subjects: mathematics and physics. The use of mathematics and physics makes our world possible, from computers and smartphones to the automation equipment used in the production of goods and services. More specifically, when it comes to automation, math and physics are used in the development of software used to prevent collisions and upsets through motion control and kinetics. If you’re interested in learning more about this subfield of automation, read on.  

What Is Motion Control? 

artificial intelligence machine

Motion control is a subfield of automation that is responsible for ensuring that every component of an autonomous system operates the way it is programmed (i.e., operating with repeatable and predictable movements). This is achieved by manipulating the speed and/or position of a device using things like actuators (devices that cause a machine to operate), hydraulic pumps, or servos (devices that convert electricity into movement). Depending on the system, ensuring that every sub-assembly operates as it should is no small feat. Though the components of a motion control system can vary widely, most will include a motor controller, a motor, and at least one amplifier, but we’ll explore that in a bit. For now, let’s dive into how math and physics make motion control possible.

Where Does Mathematics and Physics Come Into Play? 

Torque, force, and motion are all things that most of us are familiar with, at the very least in terms of how they impact the use of objects in the physical world. When studying motion control, having a clear understanding of how mathematical formulas and physical principles are vital to the process of designing complex algorithms. These algorithms are necessary for autonomous robotics to successfully operate in the physical world. 

Fortunately, the development of these algorithms can be iterative, meaning that you don’t necessarily need to get it right the first try. Simulation software like RoboLogix, LogixSim, or PLCLogix 500 allow programmers to continuously test their work in a virtual environment. PLC simulation software is also an effective learning tool for students to apply the concepts and practical information they’ve learned in class.

Kinetics is another discipline of physics that makes motion control in automation possible. Kinetics of course refers to the study of the various forces that can be applied to an object that result in the movement of said object. When designing robotics, this translates into studying and calculating things like torque and the electrical current that will be applied to the automation system. Kinetic equations help the programmer to create a model of the system so they can ensure the forces applied to the rigid robotic components are within acceptable limits.

Those already familiar with science will likely know that kinematics is a subfield of physics that is used to define the motion of points, bodies, and systems of bodies in relation to one another using geometry. When applied to robotics, kinematics is used to consider the relationship between a robot’s joint coordinates (e.g., an angle or transition distance) and the space that surrounds it. Kinematic equations make the precise movements of a robot possible and are used when designing a system that requires a robotic arm to grab an object and move it from point A to point B. It is also used to keep workers and infrastructure safe as it can help predict whether a robot’s movements will collide with an object or human.

The Components of Motion Control

As mentioned above, a basic motion control system will include a controller, a motor and an amplifier (or drive). Additional common components include things like sensors, actuators, and motors. Let’s describe these components in a bit more detail. 

Controllers – As the name implies, controllers are responsible for sending the desired commands to the amplifier or drive; it contains all of the positional information for all movements for a given process. In this respect, we can say that the controller is the brain of the motion control system; it “knows” all the movements that are required for the successful completion of the programmed tasks, and it communicates commands to the other system components. 

Amplifier – If the controller is the brain of the motion control system, the amplifier could be likened to a central nervous system. The amplifier receives the signal from the controller and supplies the required amount of power to the servo motor or actuator to perform the specified action. 

Actuators and Servo Motors – Once the actuator or servo motor receives the signal from the amplifier, the action is executed. These devices essentially convert electrical energy into mechanical energy, which allows movement of a component to a desired position.

Sensors – Provide feedback to the system so that the controllers can make the necessary adjustments so that the output is consistent. Encoders in particular are good at relaying position, velocity, and directional information back to the controller. 

In most settings, PLCs are the computers that will contain the necessary programs for the automated processes. If the machine being controlled is particularly complex, a dedicated motion controller may be utilized. 

Controlling the Motions with Physics & Geometry

Motion control is vital to automated systems to ensure that all moving components are working in synchronization with the others. Not only is this of utmost importance for the equipment to function correctly, it is also required to mitigate potential collisions and costly accidents. If you’re new to the concept of motion control or you’re interested in advancing your skills, consider applying for our Automation Technician program. There, you’ll gain experience using  LogixSim, a simulation software that will allow you to apply the mathematical theories you’ve learned  to real-world applications.


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