Momentum Control with Hierarchical Inverse Dynamics on a Torque-Controlled Humanoid

Hierarchical inverse dynamics based on cascades of quadratic programs have been proposed for the control of legged robots. They have important benefits but to the best of our knowledge have never been implemented on a torque controlled humanoid where model inaccuracies, sensor noise and real-time computation requirements can be problematic. Using a reformulation of existing algorithms, we propose a simplification of the problem that allows to achieve real-time control. Momentum-based control is integrated in the task hierarchy and a LQR design approach is used to compute the desired associated closed-loop behavior and improve performance. Extensive experiments on various balancing and tracking tasks show very robust performance in the face of unknown disturbances, even when the humanoid is standing on one foot. Our results demonstrate that hierarchical inverse dynamics together with momentum control can be efficiently used for feedback control under real robot conditions.Comment: 21 pages, 11 figures, 4 tables in Autonomous Robots (2015

Balancing experiments on a torque-controlled humanoid with hierarchical inverse dynamics

Recently several hierarchical inverse dynamics controllers based on cascades of quadratic programs have been proposed for application on torque controlled robots. They have important theoretical benefits but have never been implemented on a torque controlled robot where model inaccuracies and real-time computation requirements can be problematic. In this contribution we present an experimental evaluation of these algorithms in the context of balance control for a humanoid robot. The presented experiments demonstrate the applicability of the approach under real robot conditions (i.e. model uncertainty, estimation errors, etc). We propose a simplification of the optimization problem that allows us to decrease computation time enough to implement it in a fast torque control loop. We implement a momentum-based balance controller which shows robust performance in face of unknown disturbances, even when the robot is standing on only one foot. In a second experiment, a tracking task is evaluated to demonstrate the performance of the controller with more complicated hierarchies. Our results show that hierarchical inverse dynamics controllers can be used for feedback control of humanoid robots and that momentum-based balance control can be efficiently implemented on a real robot.Comment: appears in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 201

ロボティクスのための深層強化学習による運動シナジー発現と冗長性定量化に関する研究

Tohoku University林部充宏課

Development Of Walking Gaits For Quadruped Robot (4-Legged Robot)

The project outcomes of this project are to develop the walking gaits for the quadruped robot including trotting gait, to produce printed circuit board (PCB) for the electronic parts of the robot and to improve on the motor torque for better lifting capability and to model the gaits and implementation of the quadruped robot on ADAM software. This project is the continuation of the project completed by Mr. Yee Yuan Bin whereby he managed to develop the control system that enables the robot to perform crawling gait on the flat and horizontal surface. The control system designed involves gait control, stability control and motor control. Therefore, the existing crawling gait is to be improved into trotting gait. Besides, the modelling of the quadruped robot is to be performed using ADAMS software and the PCB for the electronic parts of the robot is to be produced in order to reduce the weight of the body. This project is split to two phases. Phase 1 is to be carried out during semester FYP 1 while Phase 2 is commenced during FYP 2. The work aspects of phase 1 are on producing printed circuit board (PCB), modelling the walking gaits using ADAMS software and also to learn about C programming for PIC18. Phase 2 is the testing stage with the presence of servomotors and circuit board as well as improvement and development of the walking gaits. At the end of project, the quadruped prototype is meant to perform forward trotting gait on flat and horizontal grounds