Electromate Announces High-Efficiency Joint for Mobile Robotics

Electromate has recently expanded its mobile robotics portfolio with the addition of the maxon HEJ 90 high-efficiency joint, a compact, integrated actuator designed for high-torque robotic joints. The new enclosed unit combines multiple motion subsystems into a single package, aiming to reduce wiring and external electronics while improving efficiency on battery-powered platforms.

The maxon HEJ 90 is designed for applications that need high torque density and a compact build, such as legged robots, autonomous outdoor systems, and mobile manipulators.

Electromate’s new maxon HEJ 90 Joint features a peak torque of up to 140 Nm. Image used courtesy of Electromate

HEJ 90 High-Efficiency Joint

The maxon HEJ 90 high-efficiency joint comes with a peak torque of 140 Nm, with configurable options that can extend to 180 Nm under modified designs. The unit features joint speeds up to 13 rad/s, making the new joint suitable for dynamic motions and responsive steering. When it comes to efficiency, the HEJ 90 comes with efficiencies as high as 86%, which reduces power losses and limits heat generation, an important consideration in autonomous robots.

Besides its torque, the HEJ 90 weighs about 1.96 kg and is designed to save space in tight mechanical setups. It measures approximately 110 mm in diameter and 90 mm in length, making it a good fit for quadruped robot legs, humanoid joints, steering or propulsion joints in wheeled robots, and mobile manipulators.

EtherCAT Control and Multi-Axis Architecture

The HEJ 90 supports EtherCAT communication with real-time control rates up to 1 kHz, enabling control of speed, torque, and position in dynamic robots. Dual EtherCAT ports enable daisy chaining, simplifying wiring in multi-joint robots. Its absolute encoder feedback and low-backlash design enable precise positioning and stable force control, which are important for robots operating on uneven surfaces or near people.

The HEJ 90 joint is suitable for a wide range of robotic applications, including mobile manipulators. Image used courtesy of Adobe Stock

The HEJ 90 is built for outdoor and industrial use and has an IP67 rating, making it suitable for wet or dusty conditions. It includes temperature sensors and internal protection for demanding duty cycles. Active cooling helps it keep performing under high loads. With forced-air cooling, it can dissipate about 250 W of heat, making it suitable for long-term field use.

Integrated Joints for Next-Gen Mobile Robots

As mobile robots face space limits, wiring challenges, and the need for compact drives, integrated joint actuators like the HEJ 90’s combination of a brushless motor, encoder, precision gearbox, servo drive electronics, and thermal monitoring in one enclosed unit make mechanical integration easier and reduce the need for a separate control enclosure.

As the use of legged and mobile robots increases in industry, there is a growing demand for actuator solutions that minimize wiring, operate reliably in challenging conditions, and use energy efficiently. Electromate’s new maxon HEJ 90 joint offers a compact and efficient option for users seeking advanced actuator solutions for mobile robots.