LiDAR: How MEMS is enabling the new trend in spatial sensing

Published by Coventor at June 15, 2018

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Coventor_June_2018_blog-Figure 1. Mode shape of a dual-axis micromirror

You’ve probably heard a lot about LiDAR. It stands for Light Detection and Ranging, and it’s playing a central role in many emerging technologies like autonomous vehicles, robotics and home automation. What sets LiDAR apart from other spatial sensing technologies is the precision and density of the distance data than can be attained from such sensors. The output signals from LiDAR sensors can be used to quickly build very detailed 3D models of a space, which makes them well suited for applications that involve autonomous vehicles and robots. Recent demonstrations of robots somersaulting over office furniture^[1] , or drones mapping every leaf in a forest^[2],are examples of feats enabled by LiDAR sensor technology. Experts forecast that LiDAR technology will experience a 12-22% compounded annual growth rate in global market size through the next decade ^[3-4], making it one of the fastest growing areas of high tech.

LiDAR systems commonly use electrostatically-actuated mirrors to rapidly scan a laser beam across a target area. These mirrors are another example of a MEMS device in an emerging application. Engineers who design such systems require rapid and accurate means of simulating and designing these mirror structures and their associated actuators. Coventor’s CoventorMP platform provides design and analysis tools which are tailored and optimized for this application.

With the MEMS+ tool of CoventorMP, LiDAR designers can quickly get analysis results reporting the capacitance, modal frequencies and harmonic behavior of LiDAR micromirrors in both linear and highly nonlinear operating regimes. An example of a MEMS+ model in a dual-axis micromirror is shown below, demonstrating one of the mode shapes of the design:

Figure 1. Mode shape of a dual-axis micromirror.

Moreover, using the MATLAB^® Simulink^® plugin of MEMS+, the full transient behavior of the micromirror can be analyzed, allowing analysis of startup, ringdown, and steady-state behavior. The transient startup signals from the same design using MEMS+ and MATLAB Simulink is shown below:

Figure 2. Transient startup behavior of a dual-axis micromirror.

Moreover, since the micromirror device exists as a system block in Simulink, the collective behavior of micromirror arrays can be examined. Each micromirror can be analyzed in-situ within a control loop, and co-simulated with readout circuit models.
As MEMS design begins to encompass elements from the systems-level, and as system-level design considerations become more important for the MEMS designer, system-level analysis capabilities, in turn, become more important. Using the tool-flow offered by MEMS+, system-level modeling becomes accessible and practical.