Research

--- Publications ---


*: Equal Contribution

--- Publication-related Projects ---

Perception-Integrated, Terrain-Aware Humanoid Locomotion Controller

Summary: Implementation of the ALIP-MPC controller on the Digit robot using perception data for terrain parameter estimation.

Paper :: Code

Exploring Kinodynamic Fabrics for Reactive Whole-Body Control of Underactuated Humanoid Robots (In Review)

Alphonsus Adu-Bredu*, Grant Gibson*, and Jessy W. Grizzle

*: Equal Contribution


Summary: We propose Kinodynamic Fabrics as an approach for the specification, solution and simultaneous execution of multiple motion tasks in real-time while being reactive to dynamism in the environment. Kinodynamic Fabrics allows for the specification of prioritized motion tasks as forced spectral semi-sprays and solves for desired robot joint accelerations at real-time frequencies. We evaluate the capabilities of Kinodynamic fabrics on and diverse physically-challenging whole-body control tasks with a bipedal humanoid robot both in simulation and in the real-world. 


Paper :: Code :: Website

Stair Climbing using the Angular Momentum Linear Inverted Pendulum Model and Model Predictive Control (In Review)

Oluwami Dosunmu-Ogunbi, Aayushi Shrivastava, Grant Gibson, Jessy W Grizzle

Summary: This paper develops a controller that enables the Cassie robot to climb stairs in simulation. Novel contributions include the exploitation of a variation of the ALIP model that allows CoM height to vary within a step, and a novel combination of virtual constraint-based control and MPC to stabilize a stair-climbing gait. 

Paper

Terrain-Adaptive, ALIP-Based Bipedal Locomotion Controller via Model Predictive Control and Virtual Constraints (IROS 2022)

Grant Gibson, Oluwami Dosunmu-Ogunbi, Yukai Gong, Jessy W. Grizzle

Summary: This paper presents a gait controller for bipedal robots to achieve highly agile walking over various terrains given local slope and friction cone information.

Paper :: Code

--- Additional Projects ---

ROS 2 Workspace for Digit Robot Python SDK

Summary:  ROS 2 workspace with packages to interface with the Python SDK for the Digit robot designed by Agility Robotics.


Repository found here

Angular Momentum Linear Inverted Pendulum (ALIP) Controllers: Point Mass & 5-Link Walker

Summary: Development and Implementation of a terrain-aware walking controller based on the Angular Momentum Linear Inverted Pendulum (ALIP). Simulation results for a pendulum and five-link robot are presented.


Pendulum Repository found here 

Five Link Robot Repository found here

Input-Output Nonlinear Model Predictive Control of Five-Link Robot for Stair Climbing

Summary: Preliminary work on achieving robust stair climbing for a planar five-link robot. Offline gait trajectories were generated using the Hybrid Zero Dynamics Framework. A novel control algorithm was developed by combining input-output linearization and nonlinear model predictive control.  


Repository found here

Three-Link Hybrid Zero Dynamics Gait Design & Control

Summary: Hybrid Zero Dynamics Optimization and Simulation for a 3-link walker. Based upon the work presented in Feedback of Dynamic Bipedal Robot Locomotion by Eric Westervelt and Jessy W. Grizzle


Repository found here

Acrobot Control Algorithms

Summary: Implemention of various control strategies for the acrobot (double pendulum model). Fully-actuated and underactuated cases are explored for the pinned model. Passive walking and Passivity-based control methods are also implemented for the floating base model walking at an incline. 


Repository found here