טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentPrigozin Amit
SubjectControl of Ultra-Fast Autonomous Vehicles in Dense Urban
Areas
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Elon Rimon
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

In recent years we witness more and more autonomous vehicles integrated into our daily routines. From logistics to military operations, and even autonomous vehicles driving between us in highways.

Most of today’s research focuses on how to preform autonomous driving under safety constrains. The goal of this research is to increase the safety envelopes and thus achieve better performance of autonomous vehicles. The objectives of the research were to achieve a complete stop from initial velocity of 10 m/s within a distance of 1 meter, and preform turn in radius of 1 meter while the autonomous vehicle maintains a constant speed of 10 m/s.

The high-speed braking relies on a novel pneumatic system. A series of suction cups where located in the rear part of the autonomous mobile robot platform. When an emergency brake is required, the suction cups are lowered to the ground and a compressor start to empty the suction cups. The high differential pressure on the suction cups creates a high normal force, which allow high friction force between the suction cups and floor. This allows the autonomous vehicle to brake under 1 meter distance.

Like the high-speed braking system, the high-speed turning system relies on pneumatic means as well. A novel suction cup was developed specifically to allow the vehicle to perform such a fast turn in such a small radius. The unique suction cup is designed in way that allows it to create only lateral force, while there is almost no tangential force at all. A series of wheels located inside the vacuum chamber of the suction cups align with the robot's driving heading direction. While in the tangent direction the wheels are in almost pure roll and therefore do not apply any friction force, in the tangential direction the wheels skidding on the ground and therefor create a massive friction force due the high normal force created by the pneumatic vacuum system.

The high-speed braking system was tested in a series of experiments. The results show that it is possible to brake the robot platform from initial velocity of 10 m/s to a complete stop within one meter, and thus reduce the braking distance in more than 40%.

The high-speed turning system turn out to be more complex. Implementation of such a system involves solving many technological problems, like the material of the sealing element. More than that, this system required very tight control with high band-width. Implementation of such a system requires high computing ability that currently the autonomous robot is not supporting. Despite these limitations a series of simulations and analytical studies of the high speed turning system showed that the system should work as anticipated once all the technological problems will be solved.

By developing those systems, I hope that soon we will see smarter and better autonomous vehicles that integrate into our daily routines, and by that improve the productivity of both the humans, and the autonomous vehicles around us: from security in dense malls, to transport parts and tools in factories.