Vision for Optoelectronics in the Automobile Thomas M. Forest General Motors Research & Development
Outline Optoelectronic Communications Intra-Vehicle Extra-Vehicle Object Detection (LIDAR) Optoelectronic Illumination Optoelectronic Sensing Summary
Disclaimer This is not an official GM presentation The opinions of one researcher Hopefully, presentations like this will open a dialog We ll tell some things we d like to do Hopefully you ll tell us some new things we can do
Intra-Vehicle Communications Two broad categories Infotainment Communications Audio, video, computer displays, etc. Control Communications Powertrain, suspension, customer convenience, etc.
Infotainment Communications Optical Infotainment systems (MOST, D2B) are already on the market Primarily used for multi-channel audio IDB-1394, an automotive variant of IEEE- 1394, is a possible emerging standard. Supports audio and video Not clear if it will be successful Suppliers have already solved most automotive issues for infotainment Temperature, manufacturing, etc.
Infotainment where s the killer app? Optical solutions continue to be more expensive than analog or digital on copper In most cases, the benefits of optical (speed, etc.) are not required Video would seem to be an exception Example - distribution of DVD Video around vehicle Doing this digitally would force us to comply with the content protection requirements of the entertainment industry Analog has acceptable performance without the headaches Limited display size quality is not an issue
Infotainment Communications While there s not universal agreement, widespread adoption of optical communication for infotainment is not certain This could change Cost reductions Content protection issues Some applications would benefit greatly Distribution of uncompressed video (camera) High resolution computer-generated displays Anything we adopt will be a standard
Control Communication Limited current use byteflight passive safety protocol Potential benefits of optical Higher speeds Longer network topologies Better EMI performance Issues with optical in control applications Cost Temperature (150º C in underhood apps.)
Control where s the killer app? Vehicle network lengths and speed requirements not that high 10 s of meters, 5 50 Mbit/s (currently) Can be done with copper Faster is not always better EMI issues may be the driving factor for optical applications in near- to mid-term Widespread adoption not certain Cost and temperature remain issues Anything we adopt will be a standard
Extra-Vehicle Communication Vehicle Vehicle, Vehicle Infrastructure Leading candidate for both applications is probably RF Optical has some compelling benefits Inherently local No spectrum allocation issues Also has some significant issues Difficult to make omnidirectional Problems with dirt, fog, snow, etc.
Object Detection Future vehicles will require substantially improved situational awareness Short Range ( within 25 meters) Blind spot avoidance, park assist, pre-crash prep. 360 degree coverage required Long Range ( within 100 150 meters) Adaptive cruise, lane keeping, pre-crash prep. Angular coverage requirements more limited Three obvious candidate technologies RADAR, LIDAR, and Vision systems
LIDAR System Types Two broad categories of LIDAR Scanned LIDAR One laser and one detector, scanned over FOV by moving mirror or prism Current systems are mechanically scanned Complicated mechanical design Fixed Beam LIDAR Multiple lasers and multiple detectors Simple mechanical design As FOV increases, cost increases (more beams)
LIDAR Characteristics Issues Poor detection of dirty targets Sensitive to weather (fog, snow, dust) Emissions must be eye-safe Performance generally not as good as RADAR Benefits Easier to identify entire target Cost less than current RADAR systems
Future of LIDAR While LIDAR currently has a significant cost advantage, it may not last New CMOS RADAR technology may be an order of magnitude less expensive To remain competitive, LIDAR performance must increase and, under the assumption of cost decreases in RADAR, LIDAR cost must decrease
Optoelectronics for Illumination LED s already widely used for indicators Obvious Applications - exterior lighting LED stop lamps, turn signals, CHIMSL, etc. LED Headlamps (very soon) Less Obvious Applications UV LED s to excite fluorescent inks Active IR illumination for night vision systems Benefits: Efficiency, long life, packaging Cost, temperature, durability still issues Looking for improved solutions
Optoelectronic Sensors - In Use Today Ambient Light Sensing Inside and Outside Controls auto headlights, displays, mirrors Sun Load Sensing Air conditioning comfort models Cam Position Sensing Rain Sense Controls automatic wipers Differences in reflection for glass/air vs. glass/water interfaces
Other Sensors - Examples There have been a number of other optoelectronic sensor applications considered Combustion Pressure Fluid Level Fluid Status (e.g., oil quality estimation) Crash / Impact Sensing Success in these areas, but other sensing methods available for these applications Cost, temperature, vibration, contamination, manufacturing issues
Potential Sensor Applications Things we d like to sense, or sense better Combustion characteristics Engine misfire Chemical composition (fuel, exhaust, coolant) Stress / strain for force or torque measurement Remote temperature sensing (catalyst, etc.) High resolution position sensing (crank, cams)
Potential Sensor Applications (Cont d) Battery State of Charge Road surface condition (ice, rain, etc.) Vehicle dynamic characteristics Acceleration, yaw rate, etc. Undoubtedly there are others You tell us Solutions must meet automotive constraints for cost, environment (temp, vibration, etc.), durability/life, etc.
Summary Several key issues appear in a number of areas Automotive cost sensitivity Harsh automotive environment Widespread use of optical communication possible, but not certain Many possibilities for automotive sensing We d like to hear from you on what else is possible