Maximizing Efficiency in Motion Control Systems

Motion Control Products from Bosch Rexroth

Experts predict that by 2025, 10-15% of jobs in three sectors, namely transportation, manufacturing, and retail trade, will have high potential for automation. As more companies adopt automated processes and technologies, the demand for motion control systems in factories and production lines has grown exponentially. Motion control systems make sure that products are assembled successfully by moving the right components to the right place, in the right orientation, at the right time. 

In this guide, we explore what motion control systems are, how they work, who benefits from them, and how to maximize their effectiveness.

What are motion control systems?

A motion control system generates mechanical motion. It is actuated by a motor and designed for precise torque control, speed, and/or position. In the automation industry, motion control systems enable accurate and controlled movement of machine parts.

Motion control systems are often used in situations that require the rapid start and stop of motion, coordination of separate elements, and exact positioning of a product.

In most cases, motion control systems use computerized controls to produce desired actions and influence force, speed, pressure, and/or positioning. More advanced systems have specialized technology to collect critical process data and feedback such as velocity or position for the improvement of future operations.

The basic structure of a motion control system

Motion control systems are composed of three basic components: a motion controller, motor driver or amplifier, and motor.

Motion controller

The motion controller is the brain of the entire system. It handles all the computational requirements of sequence execution, servo loop closure, and motion path planning. It is controlled by the end-user to accomplish commands that guide the machine’s function. Motion controllers vary depending on the number of axes, required resolution, update time, and the specific commination bus supported.

The motion controller then supplies an analog or digital low-power motor command signal to the motor drive.

Motor drive or amplifier

The motor drive receives the low-power signal from the motion controller, it when send power to the motor.

Motor drives are responsible for delivering the right amount of voltage and current to the motor that produces torque and sets the load in motion.

Drives can be analog, digital, stepper, linear, variable frequency, and servo types. Each drive has a unique function and ability. Each drive works with certain motors and some work better for specific applications.

Motor

Also known as the muscle of motion control systems, the motor converts electrical energy into mechanical energy and produces the torque needed to move to the target position.

Motors in motion control systems are classified as either DC or AC, depending on the type of power they use.

AC motors offer more versatility, controlled acceleration, adjustable torque limit, and fewer power line disturbances. DC motors, on the other hand, have a high starting torque and are easier to install and use.

Feedback device

Feedback devices can be found on both closed-loop and open-loop systems. They feed position, direction, or velocity information back to the motion controller. The controller then makes the necessary adjustments to the current to achieve the target output.

Motion control systems are widely used for industrial and manufacturing applications. They are often found in industries including:

  • Textile
  • Agriculture
  • Semiconductor and electronics
  • Printing and paper
  • Plastic and rubber
  • Oil and gas
  • Metal and machinery manufacturing
  • Medical
  • Furniture and wood
  • Food and beverages
  • Energy
  • Automotive
  • Aerospace and defense

How to improve the efficiency of your motion control system

1. Use the correct motor for the specific application

Using the appropriate motors for the application can lead to better quality output and higher energy savings. Three of the most common motors used in motion control systems today are the DC (brushed & brushless), Stepper, and Servo motors.

Brushed DC motors are simple to control, have excellent torque at low speeds, are reasonably efficient and mostly inexpensive. They produce audible noise and electromagnetic noise which could cause interference within the system. Additionally, a brushed DC motor requires constant maintenance since the brushes can and will eventually wear out.

Common applications: mobile phone vibrator, toys, handheld fans, cordless drills, car windows.

Brushless DC motors are quitter than a brushed motor since there is no contact between surfaces. For this same reason, they are more efficient as well. A brushless DC motor will provide more power than a brushed DC motor with the same size magnet. The downside of these motors is that they are difficult to control and often require a special controller.

Common applications: washing machine, air conditioner, computer fans, disk drives, drones

Stepper motors are used for precise positioning and/or speed control. They have excellent torque at low speeds and are perfect for applications with high holding torque.  They can easily be controlled with low-cost microcontrollers. The downside of a stepper motor is the noise that is created, limited torque at high speeds, and lower efficiency.  Since they constantly draw power, they tend to become hot.

Common applications: security cameras, car side mirror tilts, printers

Servo motors have excellent torque at speeds greater than 2000 rpms. With closed loop feedback, they have the highest positioning accuracy. They are required for most advanced motion control applications. The possible downsides of a servo motor are the cost and the potential jitter trying to maintain position.

Common applications: 3D printing, CNC, packaging, cartesian systems

2. Use appropriate and efficient speed drives

Today’s manufacturers seek greater machine and overall performance efficiency to stay ahead of the competition and meet changing customer needs.

The latest generation of variable frequency drives (VFDs) play a key role in accelerating operational efficiency during both design and production stages. VFDs help align the speed of the motor to the desired speed of the driven machinery. They’re also designed for lower noise, softer start, and reduced maintenance.

3. Select the right Programmable Logic Controller (PLC)

PLCs are a popular automation tool among various industries because they’re easy to use and provide precise and modifiable control.

When selecting your PLC, it’s important to define application requirements including control basics and future scalability. Other important factors to consider include:

  • Number and type of I/O
  • Necessary control functions
  • Data collection and special function requirements
  • Communication options
  • Automation experience and capabilities of plant personnel

While some plant personnel are automation-savvy, others have little experience with newer technologies. Thankfully, there are various PLCs in the market specially designed for beginners. Although often small and simple, these controllers are designed for easy expansion and possess many of the features found in larger PLCs.

4. Use only the appropriate components

Motion control systems consist of various mechanical parts such as belts and bearings. Each component will impact the overall performance of the entire system. This is why all the parts must be consistently reviewed and tested, from the design stage down through installation.

5. Schedule regular maintenance

All components go through normal wear and tear, which may result in lower system efficiency. Planned preventive maintenance eliminates costly downtime caused by a breakdown. It also extends the lifespan of the motion control system, preventing major repairs and premature replacement of machinery.

Powerful automation technologies tailored to your needs

In production lines where power, productivity, and precision of movement are of vital importance, having the right motion control system can make all the difference between success and failure.

John Henry Foster can help you implement a motion control system that is customizable to your specific application. Since 1938, we have been equipping manufacturers with robotics, automation, and industrial systems tailored to each client’s unique needs. Reach out to our team to get a quote.