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Custom Servo Motors: Why And When?

More often than once in a blue moon, a newly purchased engine would fail to meet expectations—in terms of performance, sizing, ergonomics, or cost of ownership. Some features turn out superfluous, whereas essential functions are missing. A wise solution to save disappointments and prevent trouble before it actually happens is to go after custom servo motors from the start.

Why customize

Whereas modification implies introducing particular features to tune operating variables, customization is a major redesign to deliver a totally new product based on a standard offer. In contrast to off-the-shelf solutions, tailor-made items are manufactured to comply exactly with technical specifications, or cost limitations, or personal preferences of a specific user

  • Custom servo motors are typically intended to address the following issues:
  • Meeting size and shape restrictions to facilitate integration
  • Improving protection and reinforcing structural design (e.g., to withstand excessive shocks or hazardous effects)
  • Providing performance and/or functionality to suit application requirements
  • Enabling to drive multiple axes
  • Adding peripherals (e.g, control electronics or sensors)
  • Introducing custom work algorithms
  • Ensuring network connectivity, including compatibility with user-side connectors
Customizable RDrive characteristics
RDrive servo by Rozum Robotics


Though requiring extensive investments at the initial stage, custom-made servomechanisms bring a range of financial and technical benefits in the long-term perspective, such as:

  • Saving time, efforts, and money spent on integration, operation, and maintenance
  • Efficient utilization of production space
  • Next-to-perfect alignment and interoperability with driven machines and user networks
  • Short timespan from shipment to commissioning
  • Curbing risks associated with challenging environmental conditions (e.g., explosive or flammable atmospheres)
  • Increased productivity and compliance of the manufacturing output to stringent quality assurance standards

To put it short, customization translates into tangible competitive advantages through boosted performance, enhanced convenience of use and service, and reduced expenses.

Expertise plays a role

Customizing a servomechanism requires not only time and monetary investments, but also extensive engineering efforts to implement desired functionality and meet preset specifications. Specialized expertise in building turnkey motion solutions is a valuable asset and essential prerequisite to succeed in delivering a tailor-made product.   

Specialists at Rozum Robotics know what it takes to get an actuator truly matching desired characteristics. Actually, the company‘s way into manufacturing actuators started from developing custom servo motors to accomplish an in-house project—the PULSE robotic arm.

The original intention was to simply buy an out-of-the-box robotic actuator with proper characteristics. The perfect match was defined as having an affordable price, while being robust enough to drive an industrial-grade robot and sufficiently precise to ensure accurate positioning.

The cheapest quotes came from Asia. Though good enough to assemble a hobby robot, the drives were not acceptable for a machine targeted at industrial applications due to quality and functionality issues. Established manufacturers in Europe and America had a lot of more to offer—both in terms of capabilities and robustness, but prices went up accordingly. Any minor deviation from default configurations entailed further expenses, making the idea of ordering even a single tailor-made drive infeasible. And we needed, at least, six actuators.  

Finally, we ended up with designing a servomechanism from scratch, personalizing it to our preferences and objectives. Major original features include:

  • controller, perfectly in sync with the motion core, to orchestrate angular positioning
  • two 19-bit absolute encoders to obtain feedback
  • gearbox to maximize torque output
  • a temperature sensor to secure servomechanisms from overheating

building a custom servo motor

The experience gave us valuable insights into the customization process—both the pricing pressure behind it and development tricks. We got to understand how to approach requirement gathering and utilize the output of the procedure to deliver a fully functional engine with tailored properties.

RDrive custom servo motors

Customization proposals are about just as numerous and varied as market offers of baseline servo configurations. Some involve structural changes or unorthodox mounting arrangements, others relate to connectivity or communication methods. Based on its standard lineup, Rozum Robotics proposes the below extensions and alternatives to the basic design.

RDrive servo by Rozum Robotics
RDrive servo by Rozum Robotics
  • Shape and sizing: Though the baseline range includes cylinder-shaped models of 50, 60, 70, 85 and 110 mm in diameter, the dimensions and the form factor are modifiable on demand.
  • Housing: There is an option to change the ingress protection (IP) rating to match specific process conditions or to make a motor suitable for clean rooms, autoclave, and extreme temperatures.
  • Cooling: Extra cooling, such as with a fan or water, allows to improve power density and speed output.
  • With or without a shaft: In addition to the original hollow-shaft housing, a shafted body is also available—with a round or a star shaft or with a threaded spindle and nut assembly.
  • Torque and speed: Standard specifications are from 11 to 216 Nm and 40 to 55 RPM accordingly. The parameters are optimizable upon demand.
  • Mounting method: Select either the front mount (round/ square/ NEMA) or back mount (e.g., flange, bearing, etc.).
  • Geared or gearless: In the basic configuration, RDrive engines comprise harmonic gearheads. Additional solutions include gearless versions or models incorporating a different gearbox type—spur, cycloidal, or planetary.
  • With or without controller: The RDrive series features inbuilt controller boards of in-house design specifically matched to the motion hub characteristics. Removing a controller is an optional modification.
  • Wiring: The wiring output on the back or on the side. Available lengths vary from 50 to 500 mm. Optional insulating materials—PVC, FEP; the connector selection—terminals, soldered wires, or Molex.
  • Feedback: As an alternative to the standard feedback contour of two multi-turn absolute magnetic encoders, users can choose Hall sensors or single-turn devices with power supply from batteries or otherwise.
  • Interface: Basic models support CANOpen, as well as Python and Java-based API communication. Other data exchange formats available for implementation include EtherCAT, RS232, Wi-Fi, to mention a few.

The extensive list of customizable features and extras enables constructing a turnkey motion system to satisfy whatever needs you have.

Rozum Robotics is there to provide assistance throughout the project stages—from consulting and analysis to subsequent servicing. Note that we have no customization restrictions or additional charges based on order volumes!