New Control Solutions Speed Robotics Time to Market

BY MURRAY SLOVICK

The rush to develop new robotics-based technologies and applications resembles one of those wildebeest migrations seen on the TV network Animal Planet. During 2012, for example, the number of U.S. patent filings referencing robots rose to an average of nine per week, twice the number in annual filings over the last 30 years.

Texas Instruments' EVALBOT

Industrial robotics combines electronics, control systems, artificial intelligence, computer science and bio-engineering. Robots are generally classified by their purpose: a factory robot or an industrial robot can perform jobs such as cutting and welding, while a service robot or a mobile robot adds movement to its primary tasks. A robot system generally includes sensors, actuators and a control system which is the robot’s intelligence and may be capable of supervising and interpreting vision, force and touch, as well as handling communications and I/O protocols.

The MCU and a motor controller work together to make the robot’s motors move properly. Control boards free up valuable I/O and resources from the microcontroller by offloading the task of positioning robot servos, driving DC motors and providing stepping signals for stepper motors. Once the MCU decides how fast the motor should turn then the servo controllers output a PWM signal to the DC motor controller which provides current at the required voltage.

Mouser Electronics offers the newest robotics technology solutions and components from companies such as Texas Instruments, STMicroelectronics, International Rectifier, Fairchild Semiconductor, ON Semiconductor, and Vishay, to name just a few. Let’s now look at two new-to-Mouser DC motor control solutions and an evaluation kit for robotics designed to help jump start your design projects and speed time to market.

Fairchild’s FCM8531 is an application-specific, dual-core processor for motor control applications that consists of an Advanced Motor Controller (AMC) and a MCS51-compatible MCU core. The AMC processes the algorithms specifically for motor controls and integrates the configurable processing core and peripheral circuits to perform FOC and “Sensorless” motor control. System control, user interface, communication interface, and input/output interface can be programmed through the embedded MCS51 for different motor applications. These two processors operate independently, but complement each other. Fairchild also provides the Motor Control Development System (MCDS) IDE and MCDS Programming Kit for users to develop software, compile programs, and perform online debugging.

Fairchild's MCDS Programming Kit

STMicroelectronics’ dSPIN motor drivers combine fully-digital motion control with a low RDS(on) power stage and high current capability (3 A for each H-bridge). There is no need for a dedicated MCU to perform speed profile and positioning calculations. The digital-control core communicates with the host MCU through a SPI interface, with daisy-chain capability, facilitating the implementation of cost-effective solutions in multi-motor applications. The company’s L6472 dSPIN Microstepping Motor Driver is a fully integrated solution suitable for driving two-phase bipolar stepper motors. Thanks to a new current control, 1/16 microstepping is achieved through an adaptive decay mode which is said to outperform traditional implementations. The digital control core can generate user-defined motion profiles with acceleration, deceleration, speed or target position, programmed through a dedicated register set. A complete set of protections (thermal, low bus voltage, overcurrent) meets the most demanding motor control applications.

The Texas Instruments (TI) EVALBOT is a small robotic device that features a board with a Stellaris LM3S9B92 Cortex-M3 MCU, RJ45 Ethernet connector and USB OTG (On-The-Go). The board also features a range of Texas Instruments analog components for motor drive, power supply and communications functions. Three AA batteries (included) supply power to the EVALBOT, which automatically selects USB power when tethered to a PC as a USB device or when debugging. The TI EVALBOT Kit contains wheels that are easy to attach to the board, a display, batteries, USB cable, the StellarisWare software, and all the documentation required. Two DC gear motors provide drive and steering, opto-sensors detect wheel rotation with 45° resolution and sensors are also provided for “bump” detection. Software examples provided with the EVALBOT demonstrate how to initialize µC/OS-III Real-Time Kernel and create simple tasks, such as how to use the µC/Probe to monitor and change application variables, as well as employ basic motion control functions using the robot.