MEMS-Scanner Testbench for High Field of View LiDAR Applications

Abstract

LiDAR sensors are a key technology for enabling safe autonomous cars. For highway applications, such systems must have a long range, and the covered field of view (FoV) of >45° must be scanned with resolutions higher than 0.1°. These specifications can be met by modern MEMS scanners, which are chosen for their robustness and scalability. For the automotive market, these sensors, and especially the scanners within, must be tested to the highest standards. We propose a novel measurement setup for characterizing and validating these kinds of scanners based on a position-sensitive detector (PSD) by imaging a deflected laser beam from a diffuser screen onto the PSD. A so-called ray trace shifting technique (RTST) was used to minimize manual calibration effort, to reduce external mounting errors, and to enable dynamical one-shot measurements of the scanner’s steering angle over large FoVs. This paper describes the overall setup and the calibration method according to a standard camera calibration. We further show the setup’s capabilities by validating it with a statically set rotating stage and a dynamically oscillating MEMS scanner. The setup was found to be capable of measuring LiDAR MEMS scanners with a maximum FoV of 47° dynamically, with an uncertainty of less than 1%.

Design of an Object Scanning System and a Calibration Method for a Fingertip-Mounted Dual-Modal and Dual Sensing Mechanisms (DMDSM)-based Pretouch Sensor for Grasping

“…The six datasets are combinations of two different MSM scanning patterns and three laser beam setups with different incident angles. We compare the estimation results from our proposed 3 DoF mirror estimation method and a baseline method employed in [26] that assumes pure MSM rotational motion and precise alignment between the MSM center of rotation and the incident laser beams. We generate three laser beams using the beam splitter and a static mirror.…”

“…In [25], Yoo et al proposed a PSD-based MSM test bench with 0.026 • accuracy in the 15 • MSM scanning range. Baier et al incorporated a PSD camera with a ray-trace shifting technique into their MSM test bench and achieved a measurement uncertainty of less than 1% in the 47 • MSM scanning range [26]. These existing PSD based methods assume a precise alignment of the incident laser beam and the rotation center of the MSM due to their limitation in differentiating MSM translational motion with rotational motion, which impacts their accuracy when MSM out-ofplane translation is non-negligible or the incident beam fails to align with the mirror rotation center.…”

A Fiber-Based Chromatic Dispersion Probe for Simultaneous Measurement of X-Axis and Z-Axis Displacements with Nanometric Resolutions

“…With the miniaturization of equipment and components in the industry, microscale stages have been a powerful tool and widely used in the space-limited and small-cavity fields of micro-electro-mechanical systems (MEMS) [ 1 , 2 , 3 ], precision optics [ 4 , 5 , 6 ], microscale mechanical testing [ 7 ], semiconductor manufacturing [ 8 ], and so on. To ensure the high-accuracy motion of these microscale stages, high-precision, cost-effective, and easy-mounted displacement measurement sensors are necessary and needed [ 9 , 10 , 11 ].…”