Samer Alfayad

Lightweight high performance integrated actuator for humanoid robotic applications: Modeling, design & realization

Actuation of robotic systems is still an open question and represents a big challenge. Demanding performances including high power to mass ratio, capability of producing high power at low speed within a small-occupied volume are some of the key issues that required careful consideration. These criteria aimed to increase autonomy of humanoid robots. In this paper, a novel hydrostatic transmission actuator is proposed. The proposed actuator is controlled by displacement and has capacities for energy storage. This leads to an optimal solution in terms of power consumption. First, the proposed hydrostatic actuation principle is explained. A simplified hydraulic scheme to illustrate the energy storage capability is then provided. A mathematical model of the proposed solution is detailed showing our ability to access to the payload “jerk”. The built prototype is presented and its properties are outlined. Finally, a prototype of the actuator and the preliminary results of the actuator performance are presented, demonstrating the novelty of our solution.

Comparison of several kinds of feet for humanoid robot

This paper describes our research efforts aimed in the analysis of the humanoid robot feet role during walking gait. To improve the humanoid robot walking performances, a dynamic simulation using ADAMS software is carried out. To analyze the foot model effects virtual locomotion system has been built. Four foot models are compared through two criteria: the total energy consumption and the normal contact force component. These models are plate, flexible, active and hybrid flexible active feet parts. Simulation results show the relative effects of the flexibility and the introduction of the active joint at the toes level. The results prove the efficiency of the flexible active foot model

New 3-DOFs Hybrid Mechanism for Ankle and Wrist of Humanoid Robot: Modeling, Simulation, and Experiments

This paper deals with the design of a new class of hybrid mechanism dedicated to humanoid robotics application. Since the designing and control of humanoid robots are still open questions, we propose the use of a new class of mechanisms in order to face several challenges that are mainly the compactness and the high power to mass ratio. Human ankle and wrist joints can be considered more compact with the highest power capacity and the lowest weight. The very important role played by these joints during locomotion or manipulation tasks makes their design and control essential to achieve a robust full size humanoid robot. The analysis of all existing humanoid robots shows that classical solutions (serial or parallel) leading to bulky and heavy structures are usually used. To face these drawbacks and get a slender humanoid robot, a novel three degrees of freedom hybrid mechanism achieved with serial and parallel substructures with a minimal number of moving parts is proposed. This hybrid mechanism that is able to achieve pitch, yaw, and roll movements can be actuated either hydraulically or electrically. For the parallel submechanism, the power transmission is achieved, thanks to cables, which allow the alignment of actuators along the shin or the forearm main axes. Hence> the proposed solution fulfills the requirements induced by both geometrical, power transmission, and biomechanics (range of motion) constraints. All stages including kinematic modeling, mechanical design, and experimentation using the HYDROiD humanoid robots ankle mechanism are given in order to demonstrate the novelty and the efficiency of the proposed solution.

Three DOF hybrid mechanism for humanoid robotic application: Modeling, design and realization

This paper deals with a research work aimed to develop a new three degrees of freedom (DOF) mechanism for humanoid robots. The main idea is to build hybrid (3DOF) mechanism, which avoids the drawbacks of the serial and parallel mechanisms. The new solution has to merge the advantages of both classical (serial and parallel) structures in order to achieve optimal performances. The proposed mechanism can be used as a solution for several modules in humanoid robot. The hip mechanism is taken as an example to illustrate the contribution of this paper. To evaluate the performances of the system, simulation of this new mechanism is carried out with Adams software. Geometrical and Kinematic models are developed and included in the simulation tool. Based on biomechanical data, analysis of the new kinematic structure is carried out. The design of the proposed solution is then described. Finally the first prototype developed for the HYDROi¿D robots hip is presented. This mechanism is a part of an International patent accepted at INPI- France.

New three DOF ankle mechanism for humanoid robotic application: Modeling, design and realization

Designing and control of biped robot are still open questions. Design of ankle joint which is considered one of the more compact with high power capacity and low weight is a big challenge. The very important role played by this joint during walking, makes its design and control the first step of having a robust walking biped. In this paper, a novel three dof hybrid mechanisms has been proposed. This mechanism is actuated hydraulically and uses cable technology for power transmission. The proposed solution fulfils the requirements induced by both geometrical and biomechanical constraints. At first, the geometrical and kinematics properties of the proposed solution have been developed. A simulation tool has been built using ADAMS software and used to carry out early design dimensioning of the several components. Singularity study is detailed showing the advantage of this new solution. Control method has been proposed and tested. Finally manufactured prototype of this solution is presented with preliminary results showing the performances of the mechanism. This mechanism is a part of an International patent accepted at INPI- France.

Humanoid Head Prototype with Uncoupled Eyes and Vestibular Sensors

This paper deals with the biomimetic design of a humanoid head prototype. This prototype is developed in order to offer some mechanical device for multimodality objectives, and to demonstrate the importance of uncoupled eyes mechanism in humanoid head function. Indeed, the prototype development is based on our understanding of the humans head properties in the filed of visual and vestibular capabilities. The final prototype will have 3 DOF for each eye and 2 DOF for the neck. The developed device based as on one dof for each eye and one dof for the neck is able to show the vestibular ocular reflex (VOR) and the target tracking (TT) in real time. To carry out all these capabilities, a generic visual perception processor is developed and used. The first experiments on 3 DOF mechanism are given

HYDROïD Humanoid Robot Head with Perception and Emotion Capabilities: Modeling, Design, and Experimental Results

In the framework of the HYDROiD humanoid robot project, this paper describes the modeling and design of an electrically actuated head mechanism. Perception and emotion capabilities are considered in the design process. Since HYDROiD humanoid robot is hydraulically actuated, the choice of electrical actuation for the head mechanism addressed in this paper is justified. Considering perception and emotion capabilities leads to a total number of 15 degrees of freedom for the head mechanism which are split on four main sub-mechanisms: the neck, the mouth, the eyes and the eyebrows. Biological data and kinematics performances of human head are taken as inputs of the design process. A new solution of uncoupled eyes is developed to possibly address the master-slave process that links the human eyes as well as vergence capabilities. Modeling each sub-system is carried out in order to get equations of motion, their frequency responses and their transfer functions. The neck pitch rotation is given as a study example. Then, the head mechanism performances are presented through a comparison between model and experimental results validating the hardware capabilities. Finally, the head mechanism is integrated on the HYDROiD upper-body. An object tracking experiment coupled with emotional expressions is carried out to validate the synchronization of the eye rotations with the body motions.

Modeling and Simulation of a New Integrated Electrohydraulic Actuator for Humanoid Robots

The work presented in this paper is an important step toward a better understanding of a compact hydraulic robotic actuator, based on the Integrated Electro-Hydraulic Actuator (IEHA) developed by Alfayad and Ouezdou [1]. The novel advantage of this actuator is being highly compact and autonomous (no need for central hydraulic source), while keeping a good power to weight ratio. In order to present and develop the working dynamics of this actuator, a highly detailed mathematical model for the system is presented. The proposed model is simulated using MATLAB-Simulink software to identify the effect of the internal system parameters on system dynamics and prepare an input-output test-bed model. Such test-bed model is used to obtain the transfer function of the system and its order. Analysis of the effects of the main parameters was carried out and a lower order of the system was identified. A linear model of the system is derived and validated using system identification technique. Finally, a robust motion controller is applied on the proposed linear model and the simulation results are presented.