Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

Force and impedance control for hydraulically driven hexapod robot walking on uneven terrain

A variety approach of multi-legged robot designs, especially on a large scale design with hydraulically driven actuators exist, but most of it still unsolved and used primitive techniques on control solutions. This made this area of research still far from demonstrating the scientific solutions, which is more towards developing and optimizing the algorithm, control technique and software engineering for practical locomotion (flexibility and reliability). Therefore in this thesis,the study is done to propose two categories of solution for statically stable and hydraulically driven hexapod robot, named COMET-IV, which are dynamic walking trajectory generation and force/impedance control implementation (during body start patching), in order to solve the stability problems (horizontal) that encountered when walking on extremely uneven terrains.Only three sensors are used for control feedback; potentiometers (each leg joint), pressure sensors (hydraulic cylinders) and attitude sensor (center of body). For dynamic walking trajectory generation, the fixed/determined of tripod walking trajectory is modified with force threshold-based, named as environment trailed trajectory (ETT),on each first step of foot during support phase (preliminary sensing uneven terrain surfaces). Moreover,the proposed dynamic trajectory generation is then upgraded with capability of omni-directional walking with a proposed center of body rotational-based method. The instability of using the ETT module alone and with proposed hybrid force/position control in the previous progress, during body patching on walking session is then solved using the proposed pull-back position-based force control (PPF). PPF controller is derived from the ETT module itself and supported by proposed compliant (switching) mechanism, logical attitude control and dynamic swing rising control. The limitation of PPF controller applied with ETT module for walking on uneven terrain contains extreme soft surface makes the study narrowed to the impedance control approaches as a replacement of PPF controller. Three new adaptive impedance controller are designed and proposed: Optimal single leg impedance control based on body inertia, Optimal center of mass—based impedance control based on body inertia and Single leg impedance control with self-tuning stiffness. To reduce the hard swinging/shaking of the robot's body in motion that arise after applying the proposed impedance controllers, fuzzy logic control via Takagaki-Sugeno-Kang (TSK) model is proposed to be cascaded on the input feedback of the controller.The study has verified the effectiveness of both categories of control unit (dynamic trajectory,force controller and impedance controllers) combination throughout several experiments of COMET-IV walking on uneven/unstructured terrains

DESIGN & IMPLEMENTATION OF A TWO-LEGGED HUMANOID ROBOT

Nowadays, the development of robotic field is developing rapidly. The effort in developing a robot that can act and think like human has been done by various parties including the institutions of higher learning and the private company. This paper presents the design and implementation of a two-legged humanoid robot that capable of walking forward and backward. The robot is having a total of five degree of freedom (DOF), which comprises of two DOFon each knee, two DOFon each pelvis and one DOF used as balancing mechanism. These DOF is implemented using servomotors and are controlled using microchip PIC16F877 and PIC16F84A. The most critical part in designing this robot is to achieve its stability especially when it begins to walk. The stability of the structure is solves using the counterweight mechanism. The development of this biped is done stage by stage through developing and modifying the structure, constructing the circuit, programming the controller and combining both the hardware and software part. The results that have been achieved are the stable and rigid structure and the walking motion and it will be discussed in detail in the result part of this report

Development of behaviors for a simulated humanoid robot

Mestrado em Engenharia de Computadores e TelemáticaControlar um robô bípede com vários graus de liberdade é um desafio que recebe a atenção de vários investigadores nas áreas da biologia, física, electrotecnia, ciências de computadores e mecânica. Para que um humanóide possa agir em ambientes complexos, são necessários comportamentos rápidos, estáveis e adaptáveis. Esta dissertação está centrada no desenvolvimento de comportamentos robustos para um robô humanóide simulado, no contexto das competições de futebol robótico simulado 3D do RoboCup, para a equipa FCPortugal3D. Desenvolver tais comportamentos exige o desenvolvimento de métodos de planeamento de trajectórias de juntas e controlo de baixo nível. Controladores PID foram implementados para o controlo de baixo nível. Para o planeamento de trajectórias, quatro métodos foram estudados. O primeiro método apresentado foi implementado antes desta dissertação e consiste numa sequência de funções degrau que definem o ângulo desejado para cada junta durante o movimento. Um novo método baseado na interpolação de um seno foi desenvolvido e consiste em gerar uma trajectória sinusoidal durante um determinado tempo, o que resulta em transições suaves entre o ângulo efectivo e o ângulo desejado para cada junta. Um outro método que foi desenvolvido, baseado em séries parciais de Fourier, gera um padrão cíclico para cada junta, podendo ter múltiplas frequências. Com base no trabalho desenvolvido por Sven Behnke, um CPG para locomoção omnidireccional foi estudado em detalhe e implementado. Uma linguagem de definição de comportamentos é também parte deste estudo e tem como objectivo simplificar a definição de comportamentos utilizando os vários métodos propostos. Integrando o controlo de baixo nível e os métodos de planeamento de trajectórias, vários comportamentos foram criados para permitir a uma versão simulada do humanóide NAO andar em diferentes direcções, rodar, chutar a bola, apanhar a bola (guarda-redes) e levantar do chão. Adicionalmente, a optimização e geração automática de comportamentos foi também estudada, utilizado algoritmos de optimização como o Hill Climbing e Algoritmos Genéticos. No final, os resultados são comparados com as equipas de simulação 3D que reflectem o estado da arte. Os resultados obtidos são bons e foram capazes de ultrapassar uma das três melhores equipas simuladas do RoboCup em diversos aspectos como a velocidade a andar, a velocidade de rotação, a distância da bola depois de chutada, o tempo para apanhar a bola e o tempo para levantar do chão. ABSTRACT: Controlling a biped robot with several degrees of freedom is a challenging task that takes the attention of several researchers in the fields of biology, physics, electronics, computer science and mechanics. For a humanoid robot to perform in complex environments, fast, stable and adaptable behaviors are required. This thesis is concerned with the development of robust behaviors for a simulated humanoid robot, in the scope of the RoboCup 3D Simulated Soccer Competitions, for FCPortugal3D team. Developing such robust behaviors requires the development of methods for joint trajectory planning and low-level control. PID control were implemented to achieve low-level joint control. For trajectory planning, four methods were studied. The first presented method was implemented before this thesis and consists of a sequence of step functions that define the target angle of each joint during the movement. A new method based on the interpolation of a sine function was developed and consists of generating a sinusoidal shape during some amount of time, leading to smooth transitions between the current angle and the target angle of each joint. Another method developed, based on partial Fourier Series, generates a multi-frequency cyclic pattern for each joint. This method is very flexible and allows to completely control the angular positions and velocities of the joints. Based on the work of developed by Sven Behnke, a CPG for omnidirectional locomotion was studied in detail and implemented. A behavior definition language is also part of this study and aims at simplifying the definition of behaviors using the several proposed methods. By integrating the low-level control and the trajectory planning methods, several behaviors were created to allow a simulated version of the humanoid NAO to walk in different directions, turn, kick the ball, catch the ball (goal keeper) and get up from the ground. Furthermore, the automatic generation of gaits, through the use of optimization algorithms such as hill climbing and genetic algorithms, was also studied and tested. In the end, the results are compared with the state of the art teams of the RoboCup 3D simulation league. The achieved results are good and were able to overcome one of the state of the art simulated teams of RoboCup in several aspects such as walking velocity, turning velocity, distance of the ball when kicked, time to catch the ball and the time to get up from the ground

Realistic behaviour simulation of a humanoid robot

This paper describes a humanoid robot simulator with realistic dynamics. As simulation is a powerful tool for speeding up the control software development, the proposed accurate simulator allows to fulfil this goal. The simulator is based on the Open Dynamics Engine and GLScene graphics library, providing instant visual feedback. User is able to test any control strategy without bringing damage to the real robot in the early stages of the development. The proposed simulator also captures some characteristics of the environment that are important and allows to test controllers without access to the real hardware. Experimental and simulator results are presented in order to validate the proposed simulator

Design and manufacture of a biped robot to implement the inverted pendulum foot placement algorithm

This project aims to design and manufacture a bipedal robot speci cally designed to be controlled with the Inverted Pendulum Foot Placement algorithm. This algorithm, models the robot as an inverted pendulum. This inverted pendulum is formed from the support points of the leg of the robot with the ground, to the center of gravity of the robot. Then using the kinetic and potential energy of the inverted pendulum, the correct position of the point that represent the center of gravity, is calculated so that the robot does not fall to the ground. The project includes the design and manufacture of the robot's electronics, mechanics and software. But not the implementation of the Inverted Pendulum Foot Placement algorithm although, a Test Algorithm will be created in order to test that all the mechanics, electronics and that the robot can be controlled by this type of algorithm. This robot is powered by lithium batteries and it uses six Dynamixel motors to move. The input signals are from an IMU (Inertial Measurement Unit) and the encoder inside the motors. All the electronics are controlled by a microcontroller, but the algorithm is implemented inside of a Microcomputer. Concerning the mechanics, the entire robot parts were designed in 3D models and printed using ABS plastic. There is a second design of the robot that is connected to a PC, as well as, to a power source in order to have in nite autonomy. Also a Stability Assistance has been made in order to help the algorithm development