Automated Braking System of Autonomous Trajectory Tracking Vehicle

Abstract

Advancements and breakthroughs in technology brought radical change in vehicle automation. The development of these vehicles is expected to decrease car-related accidents and to aid traffic complexity. Trajectory tracking is one approach in solving car-related accidents and traffic complexity wherein trajectory tracking control law outputs control velocities based on posture error and reference velocities. This paper focuses on automating the braking mechanism. The braking mechanism of an Automated Vehicle (AV) must provide optimum deceleration to minimize error in following a velocity profile. The vehicle platform, built by the Robotics and Automation Laboratory (RAL), equipped with lateral control and acceleration control is modified to incorporate hydraulic braking system. The master cylinder of the brake will be electro-mechanically coupled with a stepper motor in a modified slider-crank fashion. For this research, switching control logic will be employed to avoid simultaneous acceleration and deceleration that will lead to instability of the system. Four different trajectory tests have been carried out: constant deceleration test, two-stage deceleration test, left bump test and right turn test. The results show that the deceleration capability of the vehicle has been improved. Reference posture and control velocities are better followed especially when decelerating, utilizing the automated frictional brakes.