“As more and more technologies are widely used in industrial automation, we have entered the era of Industry 4.0. New technologies are emerging to enable artificial intelligence and machine learning, data analytics, industrial networks, cybersecurity and functional safety. However, most industrial automation, at the heart of all other technologies, still relies on robotics and motion control.
As more and more technologies are widely used in industrial automation, we have entered the era of Industry 4.0. New technologies are emerging to enable artificial intelligence and machine learning, data analytics, industrial networks, cybersecurity and functional safety. However, most industrial automation, at the heart of all other technologies, still relies on robotics and motion control.
Motion control and motor control often appear together, which can be a bit confusing. What is the difference between these two concepts? In industrial automation, how do we apply the right solution to one of the concepts, or both? Read on to learn the difference between motion control and motor control and how to make them work together.
What is motion control?
Motion control is a subsystem of an industrial automation system. It synchronously controls multiple motors to complete a series of movements. For example, a multi-axis robotic arm requires multiple motors to work together seamlessly to make a specific motion. Motion control is mainly used for trajectory planning, velocity planning, interpolation algorithms and kinematic transformations. Motion control systems are often found in printing, packaging and assembly applications.
As shown below, a motion control system typically consists of the following main components:
• A motion controller that generates trajectory plans and then provides control commands to motor drives.
• A motor driver that converts a motion controller’s control command (usually a speed or torque signal) into a higher power voltage or current signal to drive the motor.
• Several motors, which can execute movements according to control commands.
• The position sensor provides the position/speed data of the motor rotor to the position/speed controller for precise position/speed control.
How to make the design of a new generation of intelligent, connected and safe industrial drives easy to use, please read this blog post >>
Motor Control and Motion Control
Motor control, on the other hand, is a system or technique that focuses more on controlling the rotation of a motor. A typical motor control system adjusts one or more parameters of torque, speed, and position of an individual motor to achieve target values. Depending on the type of motor, the requirements and technology to drive the motor can vary widely. Motor controllers usually have no planning capabilities (advanced drives only have simple position and velocity planning capabilities). So, a simple way to explain the difference between motor control and motion control is:
• Motor control is part of the motion control system (usually a current loop, operating in torque control mode)
• However, sometimes we may confuse them because the position loop/velocity loop/torque loop for motor control can be used both in the motor controller and in the motion controller
Now that we know the differences between these two systems, it is clear that their design requirements and resources are also quite different.
Motor control is more focused on getting the motor to spin properly, or rather, commutate. To do this, the motor controller needs to interface with various sensors, process analog and digital signals, and generate waveforms to drive the motor. All of this happens within very short time loops, ranging from 50 microseconds to 300 microseconds.
However, motion control often acts as a system monitor, requiring commands between multiple motor controllers, data via Ethernet (EtherCAT and TSN), CAN, RS485, and other sources, as well as Human Machine Interface (HMI) panels communication between them. As mentioned above, motion controllers can also participate in some motor control tasks, such as controlling speed loops, position loops, and even torque loops. Therefore, the real-time control loop of a motion controller can vary from 100 microseconds to hundreds of milliseconds, depending on the actual task the motion controller is involved in.
Design of motion control system
The design of a motion control system can be quite complex, covering many aspects such as motor control, industrial networking, human-machine interfaces, codecs, information security, and functional safety. Therefore, it requires multiple control units to coordinate with each other in the system.
This is where a complete set of devices is needed for motion control designers to choose – and that’s where NXP and its broad portfolio of microcontrollers (MCUs) and microprocessors (MPUs) come in.
When it comes to motor controllers, NXP’s Kinetis V MCUs, Kinetis E MCUs, LPC MCUs and digital signal controllers (DSCs) offer a wide range of options, from controlling simple motors using the ARM Cortex-M0+ core, to using the Cortex-M33 core Or a high-efficiency DSC core running the FOC algorithm on dual motors. With the popular flashless i.MX RT crossover MCU, more motors can be precisely controlled simultaneously. These MCUs not only have a wide range of processing power to choose from, but also integrate peripherals that are ideal for motor control, such as high-speed, high-precision ADCs, high-speed comparators, flexible motor control timers and PWMs, and DSP accelerometers. Safety features such as fault detection and automatic shutdown work seamlessly with the industrial safety compliance provided by these devices.
Which MCU is best for your motor control design? For the latest solutions, download our comprehensive motor control guide >>
On the motion controller side, NXP offers i.MX RT crossover MCU and MPU product lines, including Layerscape and i.MX series processors. These devices support the integration of rich industrial communication interfaces such as Ethernet/IP, Profinet, EtherCAT and TSN. The multi-core architecture provides sufficient power for communication protocols, motion trajectory planning, and real-time loop control. They are also equipped with advanced timers to support multi-mode counting and flexible burst output.
As shown in the figure above, the motion control system can use a large number of MCUs and MPUs to implement multiple motor drivers to facilitate the coordinated motion of each robotic arm.
To speed up time-to-market for motion control systems, we desperately need a quick and easy way to proof-of-concept and prototyping. Therefore, NXP has been developing reference design platforms to provide rich industrial motion control functions and comply with industrial automation standards.
We recently introduced the i.MX RT industrial driver development platform, which is based on the i.MX RT crossover MCU with a foundation for multi-motor control, deterministic communication and compliance with the IEC 62443 safety standard. The quad-motor control development platform is available now and supports the full suite of NXP products, including i.MX RT crossover MCUs and EdgeLock SE050 secure elements. These devices work together to demonstrate the functions required in an industrial motor control system, such as power management, driving four motors, industrial communication interfaces, HMI touch Panel interface and safety integration.
In summary, this article introduces the definition of motion control, the difference between motor control and motion control, and industry trends in motion control system design requirements. Continue to follow NXP for more motor control solutions >>
author of this article
Daniel Hou, Technical Marketer in NXP Semiconductors’ Industrial Edge Processing Mass Market Team, supports emerging microcontroller and microprocessor use cases in the industrial segment. He has previously held positions in applied engineering and marketing in the semiconductor industry and holds a master’s degree in electrical engineering from the Rose-Hulman Institute of Technology.
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