Development of a Humanoid Robot Arm for Use in Urban Environments

The Bucknell Humanoid Robot Arm project was developed in order toprovide a lightweight robotic arm for the IHMC / Bucknell University bipedal robot that will provide a means of manipulation and facilitate operations in urban environments. The resulting fabricated arm described in this thesis weighs only 13 pounds, and is capable of holding 11 pounds fully outstretched, lifting objects such as tools, and it can open doors. It is also capable of being easily integrated with the IHMC / Bucknell University biped. This thesis provides an introduction to robots themselves, discusses the goals of the Bucknell Humanoid Robot Arm project, provides a background on some of the existing robots, and shows how the Bucknell Humanoid Robot Arm fits in with the studies that have been completed. After reading these studies, important items such as design trees and operational scenarios were completed. The completion of these items led to measurable specifications and later the design requirements and specifications. A significant contribution of this thesis to the robotics discipline involves the design of the actuator itself. The arm uses of individual, lightweight, compactly designed actuators to achieve desired capabilities and performance requirements. Many iterations were completed to get to the final design of each actuator. After completing the actuators, the design of the intermediate links and brackets was finalized. Completion of the design led to the development of a complex controls system which used a combination of Clanguage and Java

High-performance series elastic actuation

textMobile legged robots have the potential to restructure many aspects of our lives in the near future. Whether for applications in household care, entertainment, or disaster response, these systems depend on high-performance actuators to improve their basic capabilities. The work presented here focuses on developing new high-performance actuators, specifically series elastic actuators, to address this need. We adopt a system-wide optimization approach, dealing with factors which influence performance at the levels of mechanical design, electrical system design, and control. Using this approach and based on a set of performance metrics, we produce an actuator, the UT-SEA, which achieves leading empirical results in terms of power-to-weight, force control, size, and system efficiency. We also develop general high-performance control techniques for both force- and position-controlled actuators, some of which were adopted for use on NASA-JSC's Valkyrie Humanoid robot and were used during DARPA's DRC Trials 2013 robotics competition.Electrical and Computer Engineerin

Predictive Whole-Body Control of Humanoid Robot Locomotion

Humanoid robots are machines built with an anthropomorphic shape. Despite decades of research into the subject, it is still challenging to tackle the robot locomotion problem from an algorithmic point of view. For example, these machines cannot achieve a constant forward body movement without exploiting contacts with the environment. The reactive forces resulting from the contacts are subject to strong limitations, complicating the design of control laws. As a consequence, the generation of humanoid motions requires to exploit fully the mathematical model of the robot in contact with the environment or to resort to approximations of it. This thesis investigates predictive and optimal control techniques for tackling humanoid robot motion tasks. They generate control input values from the system model and objectives, often transposed as cost function to minimize. In particular, this thesis tackles several aspects of the humanoid robot locomotion problem in a crescendo of complexity. First, we consider the single step push recovery problem. Namely, we aim at maintaining the upright posture with a single step after a strong external disturbance. Second, we generate and stabilize walking motions. In addition, we adopt predictive techniques to perform more dynamic motions, like large step-ups. The above-mentioned applications make use of different simplifications or assumptions to facilitate the tractability of the corresponding motion tasks. Moreover, they consider first the foot placements and only afterward how to maintain balance. We attempt to remove all these simplifications. We model the robot in contact with the environment explicitly, comparing different methods. In addition, we are able to obtain whole-body walking trajectories automatically by only specifying the desired motion velocity and a moving reference on the ground. We exploit the contacts with the walking surface to achieve these objectives while maintaining the robot balanced. Experiments are performed on real and simulated humanoid robots, like the Atlas and the iCub humanoid robots

Implementation of a robot platform to study bipedal walking

On this project, a modi cation of an open source, 3D printed robot, was implemented, with the purpose to create a more a ordable bipedal platform proper for studying Bipedal Walking algorithms. The original robot is a part of an open-source platform, called Poppy, that is formed from an interdisciplinary community of beginners and experts. One of the robots of this platform, is the Poppy Humanoid. The rigid parts of the Poppy Humanoid (as well as the rest of the Poppy platform robots) are 3D printed, a key factor of lowering the cost of a robot. The actuators used though, are expensive commercial DC-motors that increase the total cost of the robot drastically. This high cost of the actuators of Poppy, led this project to modify cheaper actuators while maintaining the same performance of their predecessors. Taking apart the components of the cheaper actuator, only the motor, the gears and the case that host them were kept, and a new design was made to control the motor and to meet the requirements set from the commercial motors. This new design of the actuator include a 12-bit resolution magnetic encoder to read the position of the shaft of the motor, a driver to run the motor, and also an embedded Arduino micro-controller. This feature of an Arduino as part of the actuator, gives the advantage over the commercial motor, as the user has the freedom to upload his own codes and to implement his own motor controllers. The result is a fully programmable actuator hosted on the same motor case. The size of this actuator though, is di erent from the commercial one. In order to mount the new actuators to the platform, Joan Guasch designed proper 3D printed parts. Apart of these parts, Joan also modi ed the leg design, in order to add another joint on the ankle (roll) as this Degree of Freedom (DoF) is important for Bipedal Walking algorithms and was missing from the original Poppy Humanoid leg design. The modi ed robot, is called Poppy-UPC and is a 12 DoF biped platform. For the communication between the motors and the main computer unit, a serial communication protocol was implemented based to the RS-485 standard. Multiple receivers (motors and sensors) can be connected to such a network in a linear, multi-drop con guration. The main computer unit of Poppy-UPC is an Odroid-C1 board. Essentially, this board is a Quad-core Linux computer fully compatible to run ROS. Odroid is acting as the master of the network and is gathering all the informations of the connected nodes, in order to publish them in ROS-topics. That way, the Poppy-UPC is connected to the ROS environment and ROS packages can be used for any further implementation with this platform. Finally, following the open-source spirit of the Poppy platform, all the codes and information are available at https://github.com/dimitris-zervas