An article in the magazine “Embedded Systems Design” describes an algorithm that produces linear acceleration in stepper motors, but without the heavy math overhead often required. This technique, presented by Pramod Ranade, CTO at SPJ Embedded Technologies, appears in the April 2009 issue of ESD: www.embedded.com/design/multicore/21640186.The author’s algorithm uses only addition and subtraction operations to produce a triangular or trapezoidal speed profile for a stepper motor. Due to space limits in a printed magazine, this article covers only the triangular algorithm. You can download the complete C code at: /www.embedded.com/code.new. You’ll find other code on this page, too.Although the author implemented his algorithm in a combination of an MCU and an FPGA, you can still adapt his code to an MCU-firmware-only approach. The C code should compile properly regardless of which compiler you use. The author used Microsoft’s C compiler.Stepper motors require a linear increase in speed based on the motor’s characteristics and the load it will drive. If you attempt to start a stepper motor by giving it a high-speed start–akin to stomping on your car’s gas pedal–the motor can stall and take time to get up to speed with many drive pulses wasted by generating heat. That’s not what you want. Most vehicle drivers realize they cannot get from 0 to 60 mph instantly. The same holds true for stepper motors. –Jon TitusFor more information about stepper-motor drive techniques, refer to:Austin, David, “Generate stepper-motor speed profiles in real time,” embedded.com/columns/technicalinsights/56800129. (Lots of math.)–, Industrial Circuits Application Note, “Stepper Motor Basics” www.solarbotics.net/library/pdflib/pdf/motorbas.pdf.–, “Stepper Motor Reference Design,” AN155, Silicon Laboratiories, www.silabs.com/Support%20Documents/TechnicalDocs/an155.pdf. (Reference information, circuit, and code.)
Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
Robots that walk have come a long way from simple barebones walking machines or pairs of legs without an upper body and head. Much of the research these days focuses on making more humanoid robots. But they are not all created equal.
The IEEE Computer Society has named the top 10 trends for 2014. You can expect the convergence of cloud computing and mobile devices, advances in health care data and devices, as well as privacy issues in social media to make the headlines. And 3D printing came out of nowhere to make a big splash.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.