Browsing by Subject "Humanoid"
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Item Bipedal Robotic Walking on Flat-Ground, Up-Slope and Rough Terrain with Human-Inspired Hybrid Zero Dynamics(2012-12-10) Nadubettu Yadukumar, Shishir 1986-The thesis shows how to achieve bipedal robotic walking on flat-ground, up-slope and rough terrain by using Human-Inspired control. We begin by considering human walking data and find outputs (or virtual constraints) that, when calculated from the human data, are described by simple functions of time (termed canonical walking functions). Formally, we construct a torque controller, through model inversion, that drives the outputs of the robot to the outputs of the human as represented by the canonical walking function; while these functions fit the human data well, they do not apriori guarantee robotic walking (due to do the physical differences between humans and robots). An optimization problem is presented that determines the best fit of the canonical walking function to the human data, while guaranteeing walking for a specific bipedal robot; in addition, constraints can be added that guarantee physically realizable walking. We consider a physical bipedal robot, AMBER, and considering the special property of the motors used in the robot, i.e., low leakage inductance, we approximate the motor model and use the formal controllers that satisfy the constraints and translate into an efficient voltage-based controller that can be directly implemented on AMBER. The end result is walking on flat-ground and up-slope which is not just human-like, but also amazingly robust. Having obtained walking on specific well defined terrains separately, rough terrain walking is achieved by dynamically changing the extended canonical walking functions (ECWF) that the robot outputs should track at every step. The state of the robot, after every non-stance foot strike, is actively sensed and the new CWF is constructed to ensure Hybrid Zero Dynamics is respected in the next step. Finally, the technique developed is tried on different terrains in simulation and in AMBER showing how the walking gait morphs depending on the terrain.Item Methodology for creating human-centered robots : design and system integration of a compliant mobile base(2012-05) Wong, Pius Duc-min; Sentis, Luis; Deshpande, AshishRobots have growing potential to enter the daily lives of people at home, at work, and in cities, for a variety of service, care, and entertainment tasks. However, several challenges currently prevent widespread production and use of such human-centered robots. The goal of this thesis was first to help overcome one of these broad challenges: the lack of basic safety in human-robot physical interactions. Whole-body compliant control algorithms had been previously simulated that could allow safer movement of complex robots, such as humanoids, but no such robots had yet been documented to actually implement these algorithms. Therefore a wheeled humanoid robot "Dreamer" was developed to implement the algorithms and explore additional concepts in human-safe robotics. The lower mobile base part of Dreamer, dubbed "Trikey," is the focus of this work. Trikey was iteratively developed, undergoing cycles of concept generation, design, modeling, fabrication, integration, testing, and refinement. Test results showed that Trikey and Dreamer safely performed movements under whole-body compliant control, which is a novel achievement. Dreamer will be a platform for future research and education in new human-friendly traits and behaviors. Finally, this thesis attempts to address a second broad challenge to advancing the field: the lack of standard design methodology for human-centered robots. Based on the experience of building Trikey and Dreamer, a set of consistent design guidelines and metrics for the field are suggested. They account for the complex nature of such systems, which must address safety, performance, user-friendliness, and the capability for intelligent behavior.Item Realizing Torque Controllers for Underactuated Bipedal Walking Using the Ideal Model Resolved Motion Method(2014-12-16) Cousineau, Eric AndrewThis thesis presents an application of hybrid zero dynamics to realize underactuated bipedal walking on DURUS, a testbed designed and built by SRI International. The main contribution of this work is the ideal model resolved motion method (IMRMM), which is a simple method to convert ideal torque controllers to PD controllers to implement on hardware. Walking was first achieved using the proven method of the hybrid zero dynamics (HZD) reconstruction, followed by the Input-Output Feedback Linearization (IO) and Rapidly Exponentially Stabilizing Control Lyapunov Function Quadratic Programs (CLF-QPs) torque controllers implemented via IMRMM. The simulation and experimental results are presented and compared, and the best resulting specific cost of electrical transport on hardware was computed as 0.63 for the CLF-QP IM-RMM controller, and the record for walking was achieved on a separate occasion with the same CLF-QP IM-RMM controller, which yielded walking for 2 hours and 53 minutes, covering 7 km.