Autonomous Driving and the ROAD System48.pdfB 1 B 2 B 3 B 5 B 4 The transition model Case 1: A...

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m Probability Robustly-Safe Automated Driving (ROAD) Systems Changliu Liu, Graduate Student Researcher; Masayoshi Tomizuka, Professor Autonomous Driving and the ROAD System Layer 2: Learning and Decision Making The ROAD System Case Study Efficiency: Navigate to the destination in minimum time Predict the future course for each surrounding vehicle (learning and prediction); Find a trajectory in the safe region (decision making). Safety: Interact with surrounding vehicles properly Behavior 1 (B1) : Lane Following Behavior 2 (B2) : Lane Changing to the Left Behavior 3 (B3) : Lane Changing to the Right Behavior 4 (B4) : Lane Merging Behavior 5 (B5) : Lane Exiting Steady State Behavior Maneuvers Exiting Behavior The Optimization Problem in Decision Making 1. Solve the optimal control problem without the safety constraint 2. Check if the resulting trajectory violates the safety constraint 3. If no, execute the resulting trajectory 4. If yes, modify the trajectory to make it safe Baseline Planner Safety Planner Knowledge Kinematic Model Planned Trajectory + + Strategy Vehicle State Estimator Learning Center and Predictor Procedures in solving the optimization problem: To be learned To be designed Simplified The Multi-Agent System Learning and Prediction The probability of lane changing rises since the lateral speed is nonzero. After observing lane changing, the probability of lane following rises. B 1 B 2 B 3 B 5 B 4 The transition model Case 3: Overtaken by a fast vehicle Case 2: A slow front vehicle Case 1: A stationary obstacle Objective: speed tracking and lane following, e.g. the cost function penalizes 1) the deviation from the desired speed and 2) the deviation from the lane center (the target lane center is subject to change according to different strategies) Safety constraint: the distance d between the automated vehicle and the front and rear vehicles on the same lane should be greater than d min =40m. The safety index . φ = d 2 min - d 2 - ˙ d minimize a cost function for the automated vehicle subject to constraint on control, vehicle dynamics safety constraint regarding surrounding vehicles

Transcript of Autonomous Driving and the ROAD System48.pdfB 1 B 2 B 3 B 5 B 4 The transition model Case 1: A...

Page 1: Autonomous Driving and the ROAD System48.pdfB 1 B 2 B 3 B 5 B 4 The transition model Case 1: A stationary obstacle Case 2: A slow front vehicle Case 3: Overtaken by a fast vehicle

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Robustly-Safe Automated Driving (ROAD) SystemsChangliu Liu, Graduate Student Researcher; Masayoshi Tomizuka, Professor

Autonomous Driving and the ROAD System

Layer 2: Learning and Decision Making

The ROAD System

Case Study

Efficiency: Navigate to the destination in minimum time

• Predict the future course for each surrounding vehicle (learning and prediction); • Find a trajectory in the safe region (decision making).

Safety: Interact with surrounding vehicles properly

Behavior 1 (B1) : Lane FollowingBehavior 2 (B2) : Lane Changing to the LeftBehavior 3 (B3) : Lane Changing to the RightBehavior 4 (B4) : Lane MergingBehavior 5 (B5) : Lane Exiting

Steady State Behavior

Maneuvers

Exiting Behavior

The Optimization Problem in Decision Making

1. Solve the optimal control problem without the safety constraint 2. Check if the resulting trajectory violates the safety constraint 3. If no, execute the resulting trajectory 4. If yes, modify the trajectory to make it safe

Baseline Planner

Safety PlannerKnowledge

Kinematic Model Planned

Trajectory++

Strategy

Vehicle State Estimator

Learning Center and Predictor

Procedures in solving the optimization problem:

To be learned

To be designed

Simplified

The Multi-Agent System Learning and Prediction

The probability of lane changing rises since the lateral speed is nonzero.

After observing lane changing, the probability of lane following rises.

B1

B2

B3

B5

B4

The transition model

Case 3: Overtaken by a fast vehicleCase 2: A slow front vehicleCase 1: A stationary obstacle

Objective: speed tracking and lane following, e.g. the cost function penalizes 1) the deviation from the desired speed and 2) the deviation from the lane center (the target lane center is subject to change according to different strategies) Safety constraint: the distance d between the automated vehicle and the front and rear vehicles on the same lane should be greater than dmin=40m. The safety index .� = d2min � d2 � d

minimize a cost function for the automated vehicle subject to constraint on control, vehicle dynamics

safety constraint regarding surrounding vehicles