What is an integrated servomotor? (And when you actually want one)

An integrated servomotor is a single component that combines a motor, driver, motion controller and encoder into one housing, communicating with external devices through a single cable. This eliminates the need for multiple parts and wires typically found in traditional motor setups.

Inside an integrated servomotor, there is usually a stepper motor, an encoder on the rotor to know the shaft position at all times, a driver that powers the motor's windings, and a microcontroller that runs a feedback loop between the encoder and driver to accept high-level commands instead of step pulses. This feedback loop is what makes it a servo motor.

Integrated servomotors replace the traditional setup of a stepper or BLDC motor, a driver board, a controller to generate steps or commands, and an encoder. They combine these into one part with one motor, one driver, one controller, and one encoder, all functioning through a single bus cable.

The main difference between an integrated servomotor and a traditional motor setup is the feedback loop that enables continuous position measurement and correction, ensuring accurate movement. This closed-loop system prevents the motor from losing position under errors or fast moves, unlike an open-loop stepper which silently loses position.

When purchasing an integrated servomotor, consider factors like the loop rate (how fast it corrects), type and resolution of the encoder, the bus connection (multi-drop RS-485 is better for multiple axes), the software interface (real libraries with units are preferred), and whether the hardware and firmware are open-source. The M17 serves as an example of a well-rounded integrated servomotor, offering open hardware and firmware, Python and Arduino libraries, and a first-party MCP server for AI-driven control.