Motion and position sensors for the automotive industry

摘要

We are proposing a novel technique to implement low cost motion and position sensing via micro-photonic devices based on digital diffractive optics. Standard optical encoders based on conventional shadowing effect as well as more complex grating based optical encoders are now becoming commodities in the automation industry. However, they lack many of the requirements for demanding applications as in the automotive industry. The severe automotive requirements are not only linked to high performance (resolution), but also to harsh environmental issues like fast temperature drifts, vibrations, shocks, accelerations, dust, humidity, to drastic cost issues, to small size/footprint, and finally to reliability (very long MTBF or constant monitoring of the wear-out for fault tolerance). Our diffractive optics based motion and position sensors are best suited for such special environments, while providing same or higher accuracy and resolution than standard encoders without the need for slow and/or unreliable electronic interpolation methods as it is done in the vast majority of encoders on the market today. We are proposing a novel method to design, implement and replicate in mass such motion and position sensors, which make them ideal solutions for large volume - low cost - high performance - high reliability applications. As an application example, we are applying our technology to the "Steer By Wire" (SBW) technology. Our SBW implementation requires 3 different sensors, two angular encoders (hybrid and absolute) and one torque sensor.