Henrique Manuel Martins Ferrolho

Research project: 

Towards Actuation-Consistency of Redundant Systems and Better Stability for Legged Robots

My PhD research focuses on legged robots and the specific challenges associated with these platforms, e.g., robust stability, multi-contact planning. Preliminary work carried out in the early stages of my research concentrated on the offline encoding of robot kinematic capabilities with the purpose of planning whole-body configurations for a bimanual grasping target — a problem known as end-pose planning — see Figure 1. Robustness with regard to stability over unstructured environments with inclined support regions is paramount for such successful planning results.


Figure 1. Whole-body end-pose planning
with NASA's Valkyrie humanoid robot.
Figure 2. Gait and trajectory optimization
with Edinburgh's ANYmal quadruped robot. [4]


Later, I came to realise that the use of high-dimensional geometric representations can be exploited for the encoding of both internal and external constraints imposed on the system [1], [2], [3]. These specific abstractions and representations are powerful tools to enable other higher-level planning methods like end-pose planning or Center of Mass (CoM) Trajectory Optimization (TO) — see Figure 2. My goal is to investigate ways of encoding dynamic internal constraints (e.g., dynamic torque boundaries of the actuators along the kinematic chain of a robot) and external constraints (e.g. environment obstacles, terrain topology and friction) to enable fast computation of the feasible states for any given system. With such representations available, we should get closer to solving problems such as (i) devising a trajectory over unstructured terrain while maximizing robustness to external disturbances, and (ii) plan motions and environment interactions with robots which have sustained injury or faulty actuation hardware to still complete a task successfully.


Publications:

An up-to-date list of my research output should be available in one of the following external websites:


About me: 

I am a first year PhD student under the supervision of Prof. Sethu Vijayakumar at the Edinburgh Centre for Robotics. I graduated from the Faculty of Engineering of the University of Porto, where I attended the BSc./MSc. in Informatics and Computing Engineering.


References:
[1]
S. Caron, Q.-C. Pham, and Y. Nakamura, “Leveraging Cone Double Description for Multi-Contact Stability of Humanoids with Applications to Statics and Dynamics”, in Robotics: Science and System, July 2015.
[2]
S. Caron, Q.-C. Pham, and Y. Nakamura, “Stability of Surface Contacts for Humanoid Robots: Closed-Form Formulae of the Contact Wrench for Rectangular Support Areas”, in Proceedings of the 2015 IEEE-RAS ICRA, May 2015.
[3]
R. Orsolino, M. Focchi, C. Mastalli, H. Dai, D. G. Caldwell, and C. Semini, “Application of Wrench based Feasibility Analysis to the Online Trajectory Optimization of Legged Robots”, IEEE Robotics and Automation Letters, 2018.
[4]
A. W. Winkler, D. C. Bellicoso, M. Hutter, and J. Buchli, “Gait and trajectory optimization for legged systems through phase-based end-effector parameterization”, IEEE Robotics and Automation Letters (RA-L), July 2018.