TRINAMIC Motion Control technology white paper, December 04, 2018
TRINAMIC Motion Control technology white paper, December 04, 2018
In its early days, the Internet of Things (IoT) largely served as the "eyes and ears" of cloud-based services, collecting data from sensors, cameras and other input devices inhabiting the physical world, with less emphasis on manipulating or controlling the things it monitored. IoT-enabled automation and robotic applications have begun to merge, but their cost has generally limited their use to high-end industrial and commercial markets.
This is changing, however, due to increased accessibility of motor control and motion control on the one hand, and reduced cost of components such as small electrical motors. Previously reserved to high-end industrial applications and medical devices, the best motor driver ICs can now be implemented by any engineer to give their customers the best user experience possible. Fueled by these trends, embedded motion control devices have begun to enable development of smart, secure, low-cost motorized products that complement the IoT's eyes and ears with equally capable arms and hands.
The term "embedded motion control" refers to highly-integrated devices that embody precision motor control, high-performance computing, and, in many cases, communication capabilities, within a single device. It is the next stage of evolution for embedded computing which began in the late 1970's, when the advent of low-cost single-chip microcontrollers made it possible to embed intelligence within everything from microwave ovens and children's toys to cash registers and medical equipment. Most of the efficiency gains enjoyed by modern automobiles were made possible by embedded computing.
Almost two decades later, the rise of the Internet, wireless data, and higher levels of silicon integration brought embedded connectivity to everyday items like bathroom scales, fitness monitors, and home entertainment equipment. Embedded connectivity also found applications in some motorized consumer products, such as the Roomba cleaning robot. Unfortunately, the cost of a separate MCU, motor controller and analog motor driver components, and the complexity of developing the motor control software meant that connected motion control was used primarily in manufacturing automation and other industrial applications.
Increasing levels of integration helped reduce the cost and component count of motion control platforms to the point where they only needed a general-purpose MCU and a handful of analog components to implement a complete solution (Figure 1).
Recently, embedded motion controllers have emerged, which integrates these functions with a powerful MCU (Figure 2). In most cases, the on-chip processor has enough computing power to support the complex algorithms needed to precisely control one or more motors. In many cases, the devices also include Ethernet, CAN bus, or other interfaces used for IoT communication. For lower-power applications, a single package can even contain the final output stages needed to drive a modest-sized stepper, brushless PMM (BLDC/BLAC), or other type of motor. The MCU can also be programmed to drive other types of motion-producing devices, such as linear actuators and voice coils.
To accelerate development, these controllers are usually supported by libraries of firmware that provide designers with a rich set of functions that can be invoked through a standard API. The libraries typically include algorithms for several common motor control modes (Torque, Velocity and Position), for torque control i.e. Field Oriented Control (FOC), and motion modes (i.e. profiled position, profiled velocity, profiled torque, etc…).
Medical devices are one of the first markets where embedded motion control is changing expectations about product capability and safety. Infusion pumps, for example, must deliver a steady flow of precisely metered therapeutic agents to patients. Embedded controllers with IoT capability enable these pumps to be programmed and monitored either at the patient's bedside or by a centralized management application. Similarly, the IoT-enabled controllers used in wearable insulin pumps and other personal drug delivery devices can support autonomous operation while providing a patient's health metrics in real-time to a cloud-based analytics application.
Industrial automation has been an early beneficiary of embedded motion control. The low-cost, compact motor controllers can be located close to, or even built into a motor or actuator. Each module's embedded controller performs most of the basic motion control functions locally, creating a distributed control architecture that puts intelligence close to the point where data is translated into motion. This, and the controller's ability to monitor and record its motor(s) vital signs, enables embedded motion control systems to be more responsive, as well as deliver more speed and accuracy at a lower price point.
Embedded motion controllers can also monitor and log the health of the motor and the machinery it drives in real-time, enabling them to react faster to fault or alarm conditions and, in some cases, anticipate problems before they cause product defects or costly downtime. At its simplest, this involves keeping track of how many moves each subassembly has made and comparing it against a schedule for adjustments, part replacements, and other routine maintenance. This can be combined with information collected from the motors to look for early indicators of excess friction somewhere in the mechanism that could quickly lead to more serious, and expensive, problems.
In all of these applications, the controllers' embedded communication capabilities enable a machine to be just as easily monitored and controlled across a LAN by a local application server or across the IIoT by a cloud-based application.
The high levels of silicon integration, and the resulting lower cost of embedded motion control components is helping the technology find a growing number of new applications within consumer markets.
Some examples include:
Embedded motion control is making it easier and more cost-effective than ever to turn data into motion. In doing so, it is helping make existing products better and make new classes of products possible. Furthermore, development of these products will follow the trends associated with the 4th Industrial Revolution – and push them further – thanks to motor control and motion control made easily accessible; increasing the velocity in which new technological breakthroughs hit the market, the scope breakthroughs, and the impact they have.