Miniature inductive encoder is lightweight and accurate for robotic joints

Celera Motion has released a new range of miniature PCB-based ring encoders for robotic joints. Ideally suited to surgical applications with a hollow bore design to fit into rotary actuators, the IncOder Core non-contact absolute encoder is metal-free and extremely lightweight. In addition to providing the accuracy, resolution and repeatability required for surgical applications, it features a design that is immune to contamination.

Distributed and support in the UK by INMOCO, Celera’s new absolute encoder is fully contained within a printed circuit board kit. Free from a metal housing, the rotary through-bore encoder is an ergonomic fit within robotic joints and is extremely lightweight. Each sensor includes a passive rotor target, coming in at 11.8g, that is combined with an active stator comprising all the required processing electronics weighing just 2.8g. The lightweight package helps increase robotic precision and control.

Surgical application accuracy of 0.1° is combined with a resolution of 10 – 17 bits and a repeatability of ±1 LSB. This high-level sensor performance is achieved using tried and tested inductive technology, chosen for its reliability during surgical procedures.

Highly durable for use in demanding environments, the encoder is impermeable to ingress, and neither liquids or debris impact sensor readings. It can operate in all expected temperature ranges, from -20 to +85 °C, and has a temperature coefficient of <1 ppm, giving it temperature-stable measurement performance. The bearingless design also means the encoder is maintenance-free.

Minimal dimensions make the encoder flexible for a range of compact robot layouts, intended to enhance the ease and speed of OEM design and integration. The rotor has an outside diameter of 36mm with the stator having an outside diameter of 56.8mm, while the unit has a hollow bore of 10.4mm across. With no precision installation tolerances required or need for calibration, this reduces installation time and speeds up production for the robot OEM. The angle sensor is installed into the host assembly by M2 mounting holes and the unit can be screwed (and optionally dowelled) in place for fast and reliable installation.

The encoder is flexible to communication needs featuring integration with SSI, BiSS-C, SPI, and Async Serial. To connect the device, the stator features a 10-way Molex PicoClasp connector for power input and data outputs and the IncOder CORE can be supplied with an axial or radial connector.