Download or read book Whole body Trajectory Generation and Control Strategies for Multi contact Robots written by Jaemin Lee (Ph. D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental objective of robotics is to enhance the productivity of humans while interacting in potentially unstructured environments. In this sense, Human-centered robots must be fast, stable, and robust when performing varied and complicated tasks during mission execution. Although industrial robots have seen some advancements regarding motion planning and control, they are largely limited to simple pre-defined tasks in structured environments. However, to achieve highly dynamic motions for dexterous manipulation or agile locomotion in complex robots, we need to consider the use of nonlinear dynamics, complex constraints, multiple contacts, disturbances, and uncertainties. These are fundamental requirements needed to advance the use of general purpose robots dynamically interacting in a wider variety of environments. Therefore, this thesis addresses challenges that arise from the employment of optimization techniques and sophisticated realtime algorithms for the control and deployment of realistic and practical robots in human environments. Considering the above challenges, we propose efficient trajectory generation and trajectory tracking methods as the next paradigms for whole-body control (WBC). First, we formulate a class of motion planning problems to directly obtain dynamically feasible state trajectories in multi-contact robots and the corresponding control inputs. Typically, it takes a tremendous amount of time to solve the end-to-end trajectory generation problem using large-scale standard Nonlinear Programming (NLP). We propose a new sampling-based method together with a Partially Observable Markov Decision Process to break down the trajectory generation problem into tractable parts. In doing so, the number of decision variables is drastically reduced. As a result, we solve the optimization problem much faster than using existing NLP techniques. In addition, we incorporate reachability analysis tools for determining whether the planned trajectories are reachable and discard unfeasible trajectories during optimization. Because simplified models are frequently utilized in locomotion studies to generate walking patterns, planned contact locations may not be feasible due to model mismatch and robot constraints. In contrast, our method enables the generation of dynamically feasible trajectories to reach planned contact location considering full-body dynamics and realistic constraints. The proposed methods are applied to contact constrained manipulation and bipedal locomotion problems to enhance capabilities of robots maneuvering in complex environments without slip or loss of balance. Second, we explore the fundamentals of WBC and use this insight to push forward the capabilities of WBC approaches. One of the problems we explore is the verification of stability of legged robots under unknown external perturbations. In such cases, the closed-loop control system controlled by WBC approaches may become unstable if external perturbations are not properly analyzed with stability verification. To verify stability, we leverage the so-called Centroidal Dynamics of legged robots and a type of WBC dubbed Whole-Body Locomotion Control (WBLC). Using a feedback-linearized state-space model, we obtain appropriate feedback gains for WBC to make our robot stable and robust under perturbations. Another challenge of WBC stems from the reliance on classical feedback control theory. Classical PD control is unsuitable for a noisy system, therefore WBC cannot be directly applied to stochastic systems. Classical WBC approaches do not consider the covariance of the terminal states as constraints which is a more efficient way to control robots with precision. We propose a new control approach, called Hierarchical Covariance Control (HCC) to enforce covariance constraints. Our proposed HCC is a stochastic version of WBC to decrease task errors when uncertainty is substantial. The last improvement I explore regarding WBC is the employment of Model Predictive Control (MPC) instead of solving an instantaneous optimization problem, which cannot guarantee global optimality. As such, we consider longer receding time horizons for MPC, thus improving the tracking performance by reducing the accumulated error norm while executing hierarchical tasks. Overall, our research focuses on the end-to-end process spanning trajectory planning to feedback control enabling the generating of multi-contact and constrained dynamic motions of complex robots operating in realistic setups. The various contributions of this thesis are in the areas of computational efficiency for whole-body trajectory generation, robustness of WBC control algorithms, and significant improvements in trajectory tracking using WBC algorithms. We verify the proposed approaches both in simulations and real experiments using various robotic systems

Download or read book Whole Body Control for Multi Contact Balancing of Humanoid Robots written by Bernd Henze and published by Springer Nature. This book was released on 2021-11-03 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims at providing algorithms for balance control of legged, torque-controlled humanoid robots. A humanoid robot normally uses the feet for locomotion. This paradigm is extended by addressing the challenge of multi-contact balancing, which allows a humanoid robot to exploit an arbitrary number of contacts for support. Using multiple contacts increases the size of the support polygon, which in turn leads to an increased robustness of the stance and to an increased kinematic workspace of the robot. Both are important features for facilitating a transition of humanoid robots from research laboratories to real-world applications, where they are confronted with multiple challenging scenarios, such as climbing stairs and ladders, traversing debris, handling heavy loads, or working in confined spaces. The distribution of forces and torques among the multiple contacts is a challenging aspect of the problem, which arises from the closed kinematic chain given by the robot and its environment.

Download or read book Learning for Adaptive and Reactive Robot Control written by Aude Billard and published by MIT Press. This book was released on 2022-02-08 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods by which robots can learn control laws that enable real-time reactivity using dynamical systems; with applications and exercises. This book presents a wealth of machine learning techniques to make the control of robots more flexible and safe when interacting with humans. It introduces a set of control laws that enable reactivity using dynamical systems, a widely used method for solving motion-planning problems in robotics. These control approaches can replan in milliseconds to adapt to new environmental constraints and offer safe and compliant control of forces in contact. The techniques offer theoretical advantages, including convergence to a goal, non-penetration of obstacles, and passivity. The coverage of learning begins with low-level control parameters and progresses to higher-level competencies composed of combinations of skills. Learning for Adaptive and Reactive Robot Control is designed for graduate-level courses in robotics, with chapters that proceed from fundamentals to more advanced content. Techniques covered include learning from demonstration, optimization, and reinforcement learning, and using dynamical systems in learning control laws, trajectory planning, and methods for compliant and force control . Features for teaching in each chapter: applications, which range from arm manipulators to whole-body control of humanoid robots; pencil-and-paper and programming exercises; lecture videos, slides, and MATLAB code examples available on the author’s website . an eTextbook platform website offering protected material[EPS2] for instructors including solutions.

Download or read book Humanoid Robotics A Reference written by Prahlad Vadakkepat and published by Springer. This book was released on 2017-02-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humanoid Robotics provides a comprehensive compilation of developments in the conceptualization, design and development of humanoid robots and related technologies. Human beings have built the environment they occupy (living spaces, instruments and vehicles) to suit two-legged systems. Building systems, especially in robotics, that are compatible with the well-established, human-based surroundings and which could naturally interact with humans is an ultimate goal for all researches and engineers. Humanoid Robots are systems (i.e. robots) which mimic human behavior. Humanoids provide a platform to study the construction of systems that behave and interact like humans. A broad range of applications ranging from daily housework to complex medical surgery, deep ocean exploration, and other potentially dangerous tasks are possible using humanoids. In addition, the study of humanoid robotics provides a platform to understand the mechanisms and offers a physical visual of how humans interact, think, and react with the surroundings and how such behaviors could be reassembled and reconstructed. Currently, the most challenging issue with bipedal humanoids is to make them balance on two legs, The purportedly simple act of finding the best balance that enables easy walking, jumping and running requires some of the most sophisticated development of robotic systems- those that will ultimately mimic fully the diversity and dexterity of human beings. Other typical human-like interactions such as complex thought and conversations on the other hand, also pose barriers for the development of humanoids because we are yet to understand fully the way in which we humans interact with our environment and consequently to replicate this in humanoids.

Download or read book Compliant Whole body Control of Humanoid Robots written by Taizo Yoshikawa and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A major obstacle that prevents humanoid robots from accomplishing real world tasks is their inability to physically interact with, and effectively manipulate, the most common objects generally found in human environments. Even tasks that seem simple for a human remain a significant challenge for most robots. Robots generally employ precision to perform a manipulation task. Humans, in contrast, employ compliance through tactile and force feedback to overcome their imprecision, allowing them to resolve uncertainties associated with the task. The lack of compliance and force control has been indeed a major limiting factor in the ability of robots to interact and manipulate in human environments. One of the major objectives of this research is to endow humanoid robots with whole-body compliant motion abilities. With compliance, a robot overcomes position uncertainties by moving in directions that reduce contact forces, which in turn directs it towards its goal. Whole-body framework was designed to allow the robot to compliantly interact with its environment at multiple contact points. The synthesis of compliant tasks is greatly simplified by being independent of postures and constraints, which are automatically integrated in the control hierarchy. This research focuses on the development of (I) sensor-based whole-body compliant motion primitives, (II) contact sensing and contact force control, (III) whole-body multi-contact for extended support, kneeling, crawling, leaning table, and locomotion strategy to improve support in unstructured terrains, (IV) dynamic collision-free motion planning and (V) dynamic collision-free walking path planning.

Download or read book Robot Force Control written by Bruno Siciliano and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the fundamental requirements for the success of a robot task is the capability to handle interaction between manipulator and environment. The quantity that describes the state of interaction more effectively is the contact force at the manipulator's end effector. High values of contact force are generally undesirable since they may stress both the manipulator and the manipulated object; hence the need to seek for effective force control strategies. The book provides a theoretical and experimental treatment of robot interaction control. In the framework of model-based operational space control, stiffness control and impedance control are presented as the basic strategies for indirect force control; a key feature is the coverage of six-degree-of-freedom interaction tasks and manipulator kinematic redundancy. Then, direct force control strategies are presented which are obtained from motion control schemes suitably modified by the closure of an outer force regulation feedback loop. Finally, advanced force and position control strategies are presented which include passivity-based, adaptive and output feedback control schemes. Remarkably, all control schemes are experimentally tested on a setup consisting of a seven-joint industrial robot with open control architecture and force/torque sensor. The topic of robot force control is not treated in depth in robotics textbooks, in spite of its crucial importance for practical manipulation tasks. In the few books addressing this topic, the material is often limited to single-degree-of-freedom tasks. On the other hand, several results are available in the robotics literature but no dedicated monograph exists. The book is thus aimed at filling this gap by providing a theoretical and experimental treatment of robot force control.

Download or read book An Exploration of Modeling and Control Methods for Bipedal Humanoid Robots written by Melissa Jordan Cruz and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two whole-body motion planning and control methods are presented in this report: trajectory generation and tracking using Centroidal Dynamics and optimization methods and using Reinforcement Learning (RL). Centroidal Dynamics utilizes a simplified model of the robot by assuming that all of the robot’s mass is located at the center of mass of the robot. This assumption greatly reduces the computational cost at the expense of a less accurate robot model. The RL trajectory generation and control is implemented using NVIDIA’s Isaac Gym environment. Isaac Gym massively parallelizes computation by using available GPUs, greatly decreasing computation time, making it a useful tool to develop standing and walking policies using RL on humanoid robots. Both methods produced trajectories that resulted in stable XY-planar movement. The Centroidal Dynamics method produced more promising results, with stable Z movement. More work should be done on the RL method regarding reward tuning

Download or read book Control Strategies for Series Elastic Multi contact Robots written by Gray Cortright Thomas and published by . This book was released on 2019 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: As robots designed for physical interaction with humans---humanoids, exoskeletons and beyond---make their entrance into society, understanding the limitations of their interaction behavior will be key to their effective use. The state of the art method for allowing such systems to be both compliant and force sensitive is to introduce mechanical springs into the joints of these robots, making them "series elastic". But this complicates the control of these robots, making it hard to separate truth from optimism in what they will be able to accomplish using feedback control. Robots are programmed in hierarchical layers, and each layer makes assumptions about the layer below it. The planning layer assumes the plan will be followed. The whole body controller layer assumes the actuators will supply whatever torque it specifies. And the actuator control layer assumes the actuator behaves like a linear system. This dissertation studies the interfaces between these layers as they are influenced by the choice to include series elastic actuation, hoping to resolve the mismatch between assumptions and guarantees that arise from this choice. These questions lead it naturally to the lowest of the layers, where a new system identification system allows the actuator to assume a bounded uncertainty model. The dissertation then refines the insights from studying uncertain SEA models into a simpler model that explains the most important factors. It uses this to design SEA controllers that go beyond the traditional limits of passivity. These insights also apply to the problem of strength augmentation exoskeleton control. Factor of 3 amplification results are reported on a tethered, 12 degree of freedom, powered, lower body exoskeleton with four passive joints using a simplified version of the controller and a far more advanced whole body control framework. These ideas are introduced in the context of the authors's work with various testbeds and state of the art robots including a point foot biped, the DARPA virtual robotics challenge simulator, the NASA R5 Valkyrie Humanoid, and the Apptronik Sagittarius Lower Body Exoskeleton

Download or read book TOWARDS A REACTIVE MOTION GENERATION ON EXTEROCEPTIVE FEEDBACK FOR GENERALIZED LOCOMOTION OF HUMANOID ROBOTS written by Kevin Giraud--Esclasse and published by . This book was released on 2019 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humanoid robots need exteroceptive sensors such as cameras to perceive their environment and fulfill tasks in it. This thesis deals with the integration of visual information for robot control. More specifically, in order to realize a behavior, visual data are needed to drive the robot's whole body trajectory generator either on flat ground or in multicontact. We first recall how a humanoid robot is controlled for a locomotion task, starting from the reference positions sent to the planner that computes sequence of contacts used to generate centroidal trajectory. This one is injected in a Whole body trajectory generator that provides joint trajectories to be sent to the robot through a stabilizer. Depending on the type of data given by the vision block algorithm (considered as an input during this thesis), visual loops can be made at different levels of the previous pipeline. The objectives were to use on the shelf visual blocks outputs to provide experimental results bas! ed on former blocks integration. We treated first motion capture data as high level information giving them to a Pattern Generator (PG) in charge of computing steps for the robot. One goal was to realize integrative tests for the Koroibot challenge by connecting motions created to pass obstacles like stairs or a beam. Results on the robot were not satisfying due to poor motion repeatability. The fault was due to the assumptions used between model and real robot or external phenomena like mechanical wear and stabilizer effects. To have better quantification of the repeatability and reliability of the walking algorithms on the HRP2 robot, we realized experiments in collaboration with the French Metrology and Tests Laboratory (LNE). Our collaborators provided test plateforms like climatic room, adjustable angle slope and horizontal oscillations floor to measure Key Performance Indicators (KPI). Finally, to reach multicontact motions based on vision output, 2D features projecte! d on image camera plan have been expressed in a promising opti! mal control solver called DDP (Differential Dynamic Programming). It allows to take into account non-linearities of the features projection directly in the whole body trajectory generator. Simulations for locomotion motions with multicontact using simulated visual features were provided with the robot TALOS. The remaining main issue lies in the inequality constraints that are not implemented yet in the DDP solver core. In that last part, all the elements of the pipeline previously exposed are used together : from the pose specification to the motion passed on simulation that uses stabilization module before beeing sent to the actuator commands.

Download or read book Modern Robotics written by Kevin M. Lynch and published by Cambridge University Press. This book was released on 2017-05-25 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern and unified treatment of the mechanics, planning, and control of robots, suitable for a first course in robotics.

Download or read book Trajectory Planning for Automatic Machines and Robots written by Luigi Biagiotti and published by Springer Science & Business Media. This book was released on 2008-10-23 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the problems related to planning motion laws and t- jectories for the actuation system of automatic machines, in particular for those based on electric drives, and robots. The problem of planning suitable trajectories is relevant not only for the proper use of these machines, in order to avoid undesired e?ects such as vibrations or even damages on the mech- ical structure, but also in some phases of their design and in the choice and sizing of the actuators. This is particularly true now that the concept of “el- tronic cams” has replaced, in the design of automatic machines, the classical approach based on “mechanical cams”. The choice of a particular trajectory has direct and relevant implications on several aspects of the design and use of an automatic machine, like the dimensioning of the actuators and of the reduction gears, the vibrations and e?orts generated on the machine and on the load, the tracking errors during the motion execution. For these reasons, in order to understand and appreciate the peculiarities of the di?erent techniques available for trajectory planning, besides the ma- ematical aspects of their implementation also a detailed analysis in the time and frequency domains, a comparison of their main properties under di?erent points of view, and general considerations related to their practical use are reported.

Download or read book On Line Trajectory Generation in Robotic Systems written by Torsten Kröger and published by Springer. This book was released on 2010-01-10 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: By the dawn of the new millennium, robotics has undergone a major tra- formation in scope and dimensions. This expansion has been brought about bythematurityofthe?eldandtheadvancesinitsrelatedtechnologies.From a largely dominant industrial focus, robotics has been rapidly expanding into the challenges of the human world. The new generation of robots is expected to safely and dependably co-habitat with humans in homes, workplaces, and communities,providingsupportinservices,entertainment,education,heal- care, manufacturing, and assistance. Beyond its impact on physical robots, the body of knowledge robotics has produced is revealing a much wider range of applications reaching across - verse research areas and scienti?c disciplines, such as: biomechanics, haptics, neurosciences, virtual simulation, animation, surgery, and sensor networks among others. In return, the challenges of the new emerging areas are pr- ing an abundant source of stimulation and insights for the ?eld of robotics. It is indeed at the intersection of disciplines that the most striking advances happen. The goal of the series of Springer Tracts in Advanced Robotics (STAR) is to bring, in a timely fashion, the latest advances and developments in robotics on the basis of their signi?cance and quality. It is our hope that the wider dissemination of research developments will stimulate more exchanges and collaborations among the research community and contribute to further advancement of this rapidly growing ?eld.

Download or read book Field Robotics written by Philippe Bidaud and published by World Scientific. This book was released on 2012 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides state of the art scientific and engineering research findings and developments in the area of mobile robotics and associated support technologies. The book contains peer reviewed articles presented at the CLAWAR 2011 conference. A great deal of interest is vested in the use of robots outside the factory environment. The CLAWAR conference series, established as a high profile international event, acts as a platform for dissemination of research and development findings and supports the trend to address current interest in mobile robotics to meet the needs of mankind in various segments of the society. Field robotics aims to bring technologies that allow autonomous systems to assist and/or replace humans performing tasks that are difficult, repetitive, unpleasant, or take place in hazardous environments. These robotic systems will bring sociological and economic benefits through improved human safety, increased equipment utilisation, reduced maintenance costs and increased production.

Download or read book Robot Trajectory Generation and Control written by David Euros Thomas Davies and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Joint Trajectory Generation and High level Control for Patient tailored Robotic Gait Rehabilitation written by Santiago Focke Martinez and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Robotics, Gait rehabilitation, Trajectory generation, Robot-human interaction, Kinematics.

Download or read book Multi body Dynamic Modeling of Multi legged Robots written by Abhijit Mahapatra and published by Springer Nature. This book was released on 2020-02-27 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the development of an integrated approach for generating the path and gait of realistic hexapod robotic systems. It discusses in detail locomation with straight-ahead, crab and turning motion capabilities in varying terrains, like sloping surfaces, staircases, and various user-defined rough terrains. It also presents computer simulations and validation using Virtual Prototyping (VP) tools and real-world experiments. The book also explores improving solutions by applying the developed nonlinear, constrained inverse dynamics model of the system formulated as a coupled dynamical problem based on the Newton–Euler (NE) approach and taking into account realistic environmental conditions. The approach is developed on the basis of rigid multi-body modelling and the concept that there is no change in the configuration of the system in the short time span of collisions.

Download or read book Trajectory Generation for Mobile Manipulators written by Foudil Abdessemed and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work proposed two different methodologies to generating desired joint trajectories for both holonomic and non-holonomic mobile manipulators given prespecified operational tasks. The first part considers a non-holonomic platform where the generalized inverses in the resolution of a redundant system are used. The additional degrees of freedom are exploited to avoid unforeseen obstacles and joint limits. In the second part of the work a holonomic platfrom is used. In this case, the trajectory is generated using a reactive approach based on virtual impedance and additional tasks. When the robot task is about a stationary point, the mobile manipulator showed a good tracking for the manipulator. As perspective an estimate procedure must be conducted in order to estimate the contact forces and the unknown holonomic mobile manipulator parameters driving the system Computer.