Bipedal locomotion is among the most difficult challenges in control engineering. Most books treat the subject from a quasi-static perspective, overlooking the hybrid nature of bipedal mechanics. Feedback Control of Dynamic Bipedal Robot Locomotion is the first book to present a comprehensive and mathematically sound treatment of feedback design for achieving stable, agile, and efficient locomotion in bipedal robots. In this unique and groundbreaking treatise, expert authors lead you systematically through every step of the process, including: Mathematical modeling of walking and running gaits in planar robots Analysis of periodic orbits in hybrid systems Design and analysis of feedback systems for achieving stable periodic motions Algorithms for synthesizing feedback controllers Detailed simulation examples Experimental implementations on two bipedal test beds The elegance of the authors' approach is evident in the marriage of control theory and mechanics, uniting control-based presentation and mathematical custom with a mechanics-based approach to the problem and computational rendering. Concrete examples and numerous illustrations complement and clarify the mathematical discussion. A supporting Web site offers links to videos of several experiments along with MATLAB® code for several of the models. This one-of-a-kind book builds a solid understanding of the theoretical and practical aspects of truly dynamic locomotion in planar bipedal robots.

Bioinspired Legged Locomotion: Models, Concepts, Control and Applications explores the universe of legged robots, bringing in perspectives from engineering, biology, motion science, and medicine to provide a comprehensive overview of the field. With comprehensive coverage, each chapter brings outlines, and an abstract, introduction, new developments, and a summary. Beginning with bio-inspired locomotion concepts, the book's editors present a thorough review of current literature that is followed by a more detailed view of bouncing, swinging, and balancing, the three fundamental sub functions of locomotion. This part is closed with a presentation of conceptual models for locomotion. Next, the book explores bio-inspired body design, discussing the concepts of motion control, stability, efficiency, and robustness. The morphology of legged robots follows this discussion, including biped and quadruped designs. Finally, a section on high-level control and applications discusses neuromuscular models, closing the book with examples of applications and discussions of performance, efficiency, and robustness. At the end, the editors share their perspective on the future directions of each area, presenting state-of-the-art knowledge on the subject using a structured and consistent approach that will help researchers in both academia and industry formulate a better understanding of bioinspired legged robotic locomotion and quickly apply the concepts in research or products. - Presents state-of-the-art control approaches with biological relevance - Provides a thorough understanding of the principles of organization of biological locomotion - Teaches the organization of complex systems based on low-dimensional motion concepts/control - Acts as a guideline reference for future robots/assistive devices with legged architecture - Includes a selective bibliography on the most relevant published articles

A wide variety of bipedal robots have been constructed with the goal of achieving natural and efficient walking in outdoor environments. Unfortunately, there is still a lack of general schemes enabling the robots to reject terrain disturbances. In this thesis, two approaches are presented to enhance the performance of bipedal robots walking on modest terrain. The first approach searches for a walking gait that is intrinsically easily stabilized. The second approach constructs a robust controller to steer the robot towards the designated walking gait. Mathematically, the problem is modeled as rejecting the uncertainty in the guard function of a hybrid nonlinear system. Two metrics are proposed to quantify the robustness of such systems. The first metric concerns the 'average performance' of a robot walking over a stochastic terrain. The expected LQR cost-to-go for the post-impact states is chosen to measure the difficulty of steering those perturbed states back to the desired trajectory. A nonlinear programming problem is formulated to search for a trajectory which takes the least effort to stabilize. The second metric deals with the 'worst case performance', and defines the L2 gain for the linearization of the hybrid nonlinear system around a nominal periodic trajectory. In order to reduce the L2 gain, an iterative optimization scheme is presented. In each iteration, the algorithm solves a semidefinite programming problem to find the quadratic storage function and integrates a periodic differential Riccati equation to compute the linear controller. The simulation results demonstrate that both metrics are correlated to the actual number of steps the robot can traverse on the rough terrain without falling down. By optimizing these two metrics, the robot can walk a much longer distance over the unknown landscape.

This book presents the development of a new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation. The aim is to achieve a closer interaction between the robotic device and the individual, empowering the rehabilitation potential of such devices in clinical applications. A new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation is presented. Trends and opportunities for future advances in the field of assistive locomotion via the development of hybrid solutions based on the combination of smart walkers and biomechatronic exoskeletons are also discussed.

Here for the first time in one book is a comprehensive and systematic approach to the dynamic modeling and control of biped locomotion robots. A survey is included of various approaches to the control of biped robots, and a new approach to the control of biped systems based on a complete dynamic model is presented in detail. The stability of complete biped system is presented for the first time as a highly nonlinear dynamic system. Also included is new software for the synthesis of a dynamically stable walk for arbitrary biped systems, presented here for the first time. A survey of various realizations of biped systems and numerous numerical examples are given. The reader is given a deep insight into the entire area of biped locomotion. The book covers all relevant approaches to the subject and gives the most complete account to date of dynamic modeling, control and realizations of biped systems.

This work focuses on how to implement modern online-reactive control strategies developed for robots with backdrivable actuators on robots with conventional high gear ratio, position controlled motors. The vast majority of robots today have motors like this. Robots with torque-controlled proprioceptive actuators which are backdrivable and have high torque density are currently being developed. However, there are still many situations in which robots with more traditional position-controlled, high gear-ratio actuators are more appropriate. For example, since actuator weight scales exponentially with size while torque scales linearly, it is still cost-prohibitive to use torque control for robots that are large and or very tall. In addition, backdrivable actuators typically require low latency communication to function and consume much more current than high gear ratio actuators because they are dampening motion during operation. Both restrictions can make these motors prohibitively difficult to use and expensive to obtain. For these reasons, research on robots with non-backdrivable actuators is still valuable. Many of the basic assumptions made for control systems are violated when using these actuators; with the intent to develop robots capable of dynamic, robust locomotion, we will attempt to categorize these obstacles, record the attempts to overcome them, explain why or why not the interventions were successful and finally, recommend paths of inquiry for future work. Contributions from this thesis project include creation of a bipedal robotic platform for locomotion experiments, multiple gait generators for bipedal robots with non-backdrivable actuators which were tested on physical hardware, investigation of methods to compensate for non-backdrivability during locomotion and several principles for designing control systems for dynamic, stable locomotion. Supplemental media included: - dcm-disturbance-rejection-sim.mp4 - dcm-omnidirectional-walking-sim.mp4 - model-free-omnidirectional.mp4 - parametric-lip-gait-robocup.mp4 - parametric-lip-omnidirectional-walking-sim.mp4 - pebl-spline-based-traj-opt.mp4 - sinusoidal-walk.mp4 - time-optimal-mpc.mp4 - walking-in-simulation.mp4