Robotics and Control Lab


Stochastic control: nonlinear and hybrid system control, Hamiltonian approach, open-loop control of stochastic dynamical systems, use of stochastic processes for computing control

GPS-free navigation: The navigation of aerial and ground ve- hicles based on the GPS signal presents a major challenge for the general use of autonomous vehicles. The absence of the GPS signal can lead to catastrophic outcomes. We work on a feedback control design that allows a Dubins vehicle, which is a mathematicl model for limited turning rate vehicles and mobile robots, to enter a circular trajectory using only range based measurements from the vehicle to the center of the trajectory. Our work is based on a novel state space kinematic model with the state that is composed of two continuous and one discrete state variables. The evolution of the discrete state variable is not completely defined by the model and the control design has to deal with the ambiguity of this variable.

Navigation with the avoidance of unsafe configurations: Long-time planning horizons are required to safely navigate one vehicle in the presence of another, possibly non-cooperative vehicle. They give rise to computational issues preventing the real-time implementation of safe navigation algorithms. We test our results in numerical simulations and small-scale robot experiments. The image on the right shows snapshots of an experiment in which two robots safely navigate around each other until one of them succeeds to enter safely a circular sector behind the other robot. This sort of experiments help us advance the field of autonomous navigation.  

Microrobotics: In the core of the promise of using microrobots  for diagnostics, surgery, drug delivery and other potential medical applications is the design of microrobots that can be manipulated in physiological environments. Our work has been focused on modeling and controlling a 10um swimming robot, the so-called achirial microswimmer, composed of firmly connected magnetic beads which can be propelled through a fluid environment by a roational magnetic field. 

Control of a mini segway (MinSeg) device: This device is composed of an NXT Lego motor driving the wheels and an Arduino board with a shield that has a solid state gyro. The motor encoder measures wheel rotations while the gyro measures the turning rate of the board. We derived dynamic systems equations, performed numerical simulations, and designed a digital control that achieves balancing the two-wheel mechanism. We continue to use the device as an experimental platform for advanced control concepts. 

Miniature quadrotors are attractive  systems for experiments with an advanced control concept. Our work is focused on a feedback, off-board control of quadrotors that fly with an off-the-shelf on-board controller. The presence of the on-board controller completely changes the original quadrotor dynamics, which requires the off-board control to be robust,or adaptive to changes.

Multi-vehicle formation stochastic control: The illustrative movie on the right (link) shows five differential drive robots navigating into a formation. The unique property of the implemented control algorithm is that it anticipates the uncertainity of teammate navigation. We implement the Kalman smoother for computing the control based on a path-integral approach. The early version of this work received the best student paper award at the DARS 2012 symposium.

Dubins vehicle stochastic control: We use stochastic processes to model any lack of data resulting in a dynamic uncertainty, for example, an unknown target trajectory, or even a disappearing target. These stochastic models are integrated in a feedback control that anticipates the uncertainty. Follow the (link) for an animation illustrating our work on a Dubins feedback control for stochastic target tracking. The same controller robustly follows the target that goes along a straight line (link), sinusoid (link), or complex path (link). For a control under the presence of a stochastic wind, follow the (link).

Airport surface traffic management: This research has been performed in collaboration with NASA Ames and its SARDA (Spot and Runway Departure Advisor) team. We investigated the integration of ramp-area aircraft trajectories and their timing into the optimization of airport taxiway and runway operations. Our analysis included Dallas/Fort Worth (DFW) and Charlotte Douglas (CLT) International Airports. Since data for aircraft ramp area trajectories are typically unavailable, we used an inexpensive, scaled-down robot experiment to collect some critical data about aircraft trajectories. Our robot experiment was featured in the Airspace Systems Program Newsletter, Apr-Jun, 2014. (video)

Rehabilitation robotics: Understanding the relation between manipulator design, workspace and performance is important not only for a robot manipulator executing a complex task, but also for wearable robots closely interacting with human body movements, which can be used in stroke rehabilitation. So far we have studied healthy human arm movements, grasping and joint coordination in reach-to-grasp movements. We also proposed novel methods for measuring the dissimilarity of movements based on mapping the complexity between arm trajectories and a low-dimensional dissimilarity analysis. This research contributes with a quantitative analysis of high-resolution trajectory data for the purpose of diagnostics, as well as therapy planning.

Lab members (alphabetical order):
Graduate students: 
Alexey Munishkin, PhD
Jay Ryan Roldan, PhD 
Marco Carmona, PhD 

Andrew Wong, MS
Margaret Clinton, MS (co-advised  with  Prof. Wehner)
Won Ko, MS

Former lab members:

Graduate students: 
Megan Boivin, 2021, PhD thesis (co-advised with Prof. Wehner), "Study of Kinesthetic Feedback Control for
    Compliant Proprioceptive Touch for Soft Robotic Finger-Like Actuators"

William Jeremy Coupe, 2017, PhD thesis, "Optimization of Ramp Area Aircraft Push Back Time Windows in
    the Presence of Uncertainty", Aerospace Engineer, NASA Ames
Zhi Li, 2014, co-supervised PhD thesis, "The Synergy of Human Arm and Robotic System",
    now Assistant Professor, Mechanical Engineering Department, Worcester Polytechnic Institute
Ross Anderson, 2014, PhD thesis, "Uncertainty-Anticipating Stochastic Optimal Feedback Control of Autonomous
    Vehicle Models", Senior Software Engineer, Waymo

Leo Chen, 2019 MS, "Navigation of the Cozmo Robot using Computer Vision"
Joseph Grant, 2018, MS, "2-D Lidar Slam with V-REP Simulated Robot"
Alex Aranburu, 2018, MS thesis, "IMU Data Proceessing to Reconize Activities of Daily Living with Smart Headset"
Brad Thompson, 2017, MS, "A Study of Reinforcement Learning Improvement of Dubins Vehicle Circumnavigation Based Upon Range Measurements"
Hsin-Liang Liu, 2016, MS, "Dubins Vehicle Circumnavigation Controller: UAV Circumnavigation
    Study and Simulation"

Jay Ryan Roldan, 2016, MS thesis, "Robotic Rehabilitation Gaming Strategies and Low-Dimensional
    Analysis of Hand Trajectories"
William Jeremy Coupe,  2013, MS thesis, "Robot Experiment Analysis of Airport Ramp Area Time
    Constraints and Generation of Optimal Taxiway Schedules"

Georgi Dinolov, AMS graduate student (first-year advisee)
Chien-Pin Chen, CE graduate student
(visiting student)
Iris Huang, visiting graduate student
Michael Murray, CE graduate student (visiting student)
Sisi Song, AMS graduate student (first-year advisee)

Undergraduate students: 
Zachary Lamb, 2021, B.S. thesis, "Multi-Phase Non-Linear/LQR Control Design for a 2D Reusable Launch Vehicle"
Rory Grant, 2019, B.S. thesis, "Soft Robotic Finger Simulation Control"
Minghan Zhu, 2019, B.S. thesis, "Robot Following Control"
Jacob Stelzriede, 2018, B.S. thesis, "Navigation with Cozmo Modeled as a Two Wheeled Robot"
Cooper Smith, 2017, B.S. thesis, "Development of a Variable Output Maximum Power Point
Tracking Controller for Photovoltaic Systems"

Javier Ruiz, 2017, B.S. thesis, "Control and Estimation of a Self-Balancing MinSeg Robot"
Alexey Munishkin, 2016, B.S. thesis, "Control of a 'Desktop' Quadrotor"
Travis Rogers, visiting student
Jenny Anne Maun, 2015, B.S. thesis, "Quantifying the Progress of Learning of Hemiparetic Stroke
    Patients Performing in a Circle-Tracing Experiment"
Olivia Carey-de la Torre, 2015, B.S. thesis, "Modeling and Control of a MinSeg-like Robot"
Edwin Ramirez, undergraduate researcher
Aaron Palmer, junior researcher