trajectory planning and steering control for evasive steering assist
2022-01-0096
03/29/2022
- Event
- Content
- Recently, vehicle safety has drawn great attention from both academia and industry. Increasing number of vehicles on market are equipped with active safety features, such as forward collision warning (FCW), automatic emergency braking (AEB), lane departure warning (LDW), lane departure assist (LDA), etc. While AEB is able to mitigate frontal collision or reduce collision impact by active braking, braking alone is not as effective as steering when host vehicle is in high speed. The reason is that when host speed is high, it takes a long time and distance for host vehicle to brake to full stop. For example, if the host vehicle travels at 24m/s and it brakes with a deceleration of -6m/s^2, it takes 4s and 48m to reach full stop. If the host speed is 30m/s and brakes with -6m/s^2, to stop the host vehicle, it needs 5s and 75m. But it may just take around 2s for an evasive steering to avoid collision compared with 5s of braking alone. That’s why evasive steering is more effective in avoid collision in high speed than AEB. The evasive steering assist (ESA) supports the driver to steer by amplifying his/her steering maneuver in the case of an imminent front collision with another vehicle or VRU. If the driver is judged to induce a steering maneuver to avoid an imminent threat, but that steering input is just not enough to avoid the collision, then an additional steering will be applied in the direction of the driver input. In this process, the host vehicle will move around the obstacle with a safe distance. In this paper, we will discuss our recent development effort in trajectory planning and steering control in ESA. The 5th order jerk minimum trajectory is designed taking consideration of obstacle position. Then an LQR controller is utilized to calculate the steering angle needed to track the trajectory. Real car tests are conducted in test track with an EuroNCAP-style balloon car as an obstacle. The test cases involve stationary obstacle as well as moving obstacle and braking obstacle.
- Citation
- Zhang, G., Wang, Q., Mujumdar, T., and Sugiarto, T., "trajectory planning and steering control for evasive steering assist," SAE Technical Paper 2022-01-0096, 2022, .