Advanced motion control meets open sourceMarch 06, 2019
Stepper and servomotors have long been popular in high-end manufacturing and heavy industry. With advanced control features, these motors represented an excellent investment, but were much too expensive for many low-end applications.
Due to several factors related to mass manufacturing and the open-source movement, stepper and servomotors have dropped in price, and novel control solutions that integrate open-source architectures are coming online.
During the late 20th century, technology reached a point where high-tech advances required not just an engineering degree and a machine shop, but also a chain of technological knowledge and rights that were difficult, if not impossible, for a small company to obtain. Of course there was innovation, such as the proliferation of IBM-compatible PCs, or even those that ran on an Apple OS or Unix. The operating system running each computer was proprietary as was the hardware inside, meaning systems could only be customized to a certain point. An alternative was introduced in 1991 when Linus Torvalds released the free and open-source Linux operating system.
Fast-forward nearly 30 years, and Linux itself has evolved and matured, becoming a vital part of the computing ecosystem. However, this open concept is traceable even further back to Richard Stallman’s GNU project from the early 1980s, has had far-reaching effects. The open-source concept eventually spread to hardware, in large part because of Arduino’s introduction as an open computing platform in the early 2000s. This open-source model is now starting to make its way into actual open-source silicon, such as chips based on the RISC-V open instruction set architecture (ISA). This means that not just software and dev boards, but the actual microcontrollers that power them, can be open source as well. This represents freedom not just from the expense of purchasing the design, but also the ability to modify things to suit a specific project’s needs.
Mass manufacturing for sophisticated motors
Along with, and arguably because of, this open-source revolution, stepper motors, servos and brushless DC (BLDC) motors started to see more demand in consumer-level applications. The 2010 time frame brought affordable 3D-printing and other computer-controlled tools, along with the proliferation of drones and personal robotics. This meant that advanced motors and controllers were needed in larger quantities. With the need for more advanced motors, mass manufacturing continued to drive prices down, supplying more market entrants into this cycle.
The result is sophisticated motors at a price never before seen, along with a wide variety of readily available supporting hardware. This kind of motor requires more involved control, but as processing power has improved and miniaturized, low-level functions can be passed off to embedded motion controllers. In some cases, this hardware can be integrated into the motor itself, for a true all-in-one solution that does not require constant supervision by a higher-level microcontroller unit (MCU).
Open-source ISA motor control
Consider that when open-source concepts are applied to motor controller hardware, this has benefits beyond cost and availability in the form of time savings and the ability to customize things to suit an application. Trinamic is taking advantage of this with their recently announced Rocinante family of motor drivers. These drivers feature an embedded RISC-V ISA core, which allows for enhanced features such as condition monitoring and predictive maintenance capabilities.
While the RISC-V architecture is stable and battle-tested, system designers might reasonably question the long-term support for such a system in applications with long development cycles. This is addressed directly by the non-profit RISC-V Foundation, which states that, “RISC-V ISA delivers a new level of free, extensible software and hardware freedom on architecture, paving the way for the next 50 years of computing design and innovation.”
So while chip designs change rapidly, the underlying architecture is meant to last decades — an eternity in computer hardware terms. This might be optional for some consumer applications, but for industrial, medical and military hardware, which go through arduous qualification processes and customizations, being able to maintain systems in the long term is critical. Using RISC-V architecture, system engineers can design rapidly and rely on hardware that will be supported far into the future.
Trinamic, a global leader in embedded motor and motion control, is a major supporter of open-source software, hardware and now silicon with the Rocinante RISC-V motor controller project. This expands on current product offerings, which feature a wide variety of motors and drives, system-on-modules, and motion controller ICs. With these components, system designers can implement advanced motion control in this expanding field, without having to be experts themselves.