Torque sensor improves functional safety in cobots

19th February 2020

Alex Lynn

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To address the growing demand for safe collaborative robots in manufacturing, TE Connectivity (TE), a world leader in connectivity and sensors, has designed a safety torque sensor with integrated and improved functional safety, including increased accuracy and speed, in the next generation of human-robot collaboration.

TE’s ring-shaped safety torque sensor, which can be integrated at each cobot joint, meets the new level of safety requirements up to ISO13849 Category 4 PL e thanks to two electrically segregated channels with no common cause failure. Additional benefits of the safety torque sensor include:

Low susceptibility to cross loads: TE’s safety torque sensor has been primarily designed for collaborative robot applications and to be assembled on harmonic drive gear boxes that result in a highly complex stress state. The sensor design is then optimised to reduce axial, radial load and tilting moment susceptibility providing increased accuracy.
Customisable mechanical interface: Systems like robots require highly integrated components and the safety torque sensor is available with customised mechanical interfaces. The low-profile sensor has an overall height lower than 20mm, but can easily be adapted in terms of size and sensing range to meet customer application requirements. If needed, the sensor can be used as a sealing wall to seal a gear box, all while maintaining high overload capability to help prevent sensor failure.
Digital I2C electrical interface: The standard electrical interface is an I2C serial digital interface with 400kHz communication rate allowing ease of integration. Other electrical interfaces may be designed to fit with customer requirements.
Innovative microfused technology: Microfused technology eliminates age-sensitive organic epoxies used in traditional load cell designs, thus providing a longer life span and zero stability issues resulting from problems with ageing resin. Instead, strain gauges are bonded to the mechanical part using proven microfused technology from TE.

“Providing next-generation sensor solutions to meet safety critical applications continues to be our priority at TE Connectivity,” said Ricardo Garcia, Product Manager, Force and Torque Sensors. “Our safety torque sensor balances the demand for safety with accuracy and speed as it relates to human-robot collaboration. With low susceptibility to crosstalk, a customisable mechanical interface and a standard I2C digital output, this sensor can be easily integrated and adapted to meet our customers’ requirements.”