2021 Virtual Undergraduate Research Symposium
2021 Virtual Undergraduate Research Symposium
Observed Control Development
Observed Control Development
PROJECT NUMBER: 63 | AUTHOR: Elissa Himes, Mechanical Engineering
MENTOR: Andrew Petruska, Mechanical Engineering
GRADUATE STUDENT MENTOR: Austin Oltmanns, Mechanical Engineering
ABSTRACT
Nonlinear control theory is a research area that looks at ways to control nonlinear systems in an efficient way. This project entailed creating an obstacle avoidance algorithm using a non-linear control paradigm. The obstacle avoidance uses a smoother and observer-based system to calculate and minimize a cost function related to the proximity of an obstacle. A dynamic simulation of the nonlinear system under an LQR controller is performed along with a cost calculation based on obstacle proximity for a horizon. Using a smoother and observer-based system, the control trajectory is iteratively calculated to minimize the obstacle proximity measurement. At each step of the control algorithm, the starting control calculated from the previously simulated sequence is applied. This project was implemented in ROS and simulated using a Husky robot in Gazebo. This project demonstrates how the simulation and testing by weighting the amount of influence the obstacle avoidance had on the robot enabled the robot to avoid or drive around an obstacle on its way to its destination.
PRESENTATION
AUTHOR BIOGRAPHY
Elissa is a senior in Mechanical Engineering with a minor in Robotics. Next year, she will continue her education here at Mines with a non-thesis Masters’s in Robotics. She has enjoyed participating in other research projects through the M3Robotics lab in the Mechanical Engineering Department including testing a program that manipulates a magnetic needle in a magnetic field using a Helmholtz coil and helping write equations to describe the movement of the magnet in the magnetic field. Elissa hopes to work with autonomous robotic systems once she graduates.
Some nice ideas for modifying the obstacle avoidance algorithm. I also noticed that the robot trajectory seems to continue to move away after the robot has passed the obstacle. Is this due to the same effect you mentioned in terms of the algorithm not considering the relative velocity? One other quick question: what is ross?
Thank you for the question.
Yes, the reason the robot keeps moving away from the obstacle point after it has already passed it is due to the fact that the cost function is completely based on distance to the obstacle and nothing else (like the aforementioned velocity or time to collision) The algorithm tries to minimize the cost and maximize the distance so it will continue to move away from the obstacle until it has a cost close to zero before correcting it’s path. A small part of this also depends on the shape of the superellipsoid.
ROS (Robot Operating System) is a collection of open-source software that has a lot of built-in capabilities that make it ideal for robot development.
Elissa, great presentation and well-designed poster. Figure 3 was nicely done to show how the different intensities react to the obstacle. Nice job.