PDF《arc》

Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Bo-Chiuan Chen Prof.

Huei Peng Vehicle Active Safety Systems Warning and Control Warning and Control for for Vehicle Rollover Prevention Vehicle Rollover Prevention Dept. of Mechanical Engineering and Applied Mechanics University of Michigan Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Rollover Fatality Rates Rollover Fatality Rates All Vehicles Utility Vehicle Utility Vehicle Small Pickup Standard Pickup Small Car Minivan Standard Van Medium Car Large Car Source: 1991-94 Average/Annual deaths per million registered vehicles provided by

19 28

34 40

47 59

93 98

47 Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Traffic Safety Fact

1996 Traffic Safety Fact

1996 Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc New SUV Rollover Stickers New SUV Rollover Stickers News Released on March 5, 1999. Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Heavy Truck Sport Utility Vehicle Rollover Warning Application Rollover Warning Application Pickup Light Truck Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc ?Acceleration or Roll Angle Threshold -Early warning safety monitor (Rakheja and Pich? 1990) -Lateral load transfer ratio (Preston-Thomas and Woodrooffe 1990) -Rollover advisory sign on highway exit ramps (Freedman et al. 1992) -Automatic Truck Rollover Warning System (McGee et al. 1992) -Rollover stability advisor system (Winkler et al. 1998) Literature Review ( Literature Review (Rollover Warning Rollover Warning) ) Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Literature Review ( Literature Review (Rollover Warning Rollover Warning) ) ?Energy threshold -Rollover Prevention Energy Reserve (RPER) (Nalecz et al. 1987) -RPER = the energy needed to bring the vehicle to its tip- over position - the rotational kinetic energy -RPER is positive for non-rollover cases, and when it becomes negative, a rollover will occur if no action is done to take energy out of the roll mode. Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Disadvantages of Existing Algorithms Disadvantages of Existing Algorithms ?The ?distance? away from these threshold levels is not an intuitive measure. ?Use the information to determine the rollover threat at current time. ?A method which assess rollover threat into the future, could give us a better perspective. New Proposal: Time-To-Rollover (TTR) metric New Proposal: Time-To-Rollover (TTR TTR) metric Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Time To Rollover ( Time To Rollover (TTR TTR) ) ? ?TTR: TTR: Index defined to assess rollover threat in this research. Steering angle Vehicle Model Vehicle Model Roll angle TTR TTR Roll angle exceeds threshold? Roll angle exceeds threshold? Yes now Future No Time <

1sec? Time <

1sec? Yes No TTR=1sec Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc TTR TTR Calculations Calculations Initial Conditions at the Kth Sampling Time Steering Angle, Lateral Accel. Steering Angle, Lateral Accel. Roll Angle of the Sprung Mass Roll Angle of the Sprung Mass Model Integrated for up to

1 Seconds Model Integrated for up to

1 Seconds TTR TTR (real-time) Lateral Acceleration Roll Motion Steering angle Yaw Model Yaw Model Roll Model Roll Model TTR Calculation TTR Calculation Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Desired TTR Desired TTR ?For rollover cases, a straight line with slope= -1 is created starting from the rollover point backwards in time. ?It gives a uniform ?countdown? toward rollover threats and thus serves well as the basis of warning/control. TTR=0.5 TTR=0.5 TTR=0.5 The vehicle will rollover 0.5 sec later. Warning and Control of Vehicle Rollover Prevention Automotive Research Center arc Train NN to approach the Desired TTR Neural Network ( Neural Network (NN NN) Architecture ) Architecture Layer