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Abstract: We design a new high performance integrated electro-hydraulic actuator (IEHA). We propose a new solution to a still open question in robotics, to provide an efficient and compliant actuation. The proposed actuator, which is dedicated to motorize independently each joint of a robotic system is designed to be fixed as near as possible to the joint itself, enhancing the performances while reducing the usual drawbacks of classical hydraulic actuation. The novel IEHA contains an integrated micro-pump with a floating barrel allowing the inversion of the flow direction without inverting the rotation of the input electric motor. The integration of a micro-valve and a rotary hydraulic distributor ensure the compactness of the proposed solution. In this paper, first, the proposed hydraulic actuation principle is given in detail. Then the designed prototype and the first experiments are presented demonstrating the novelty and the efficiency of our solution. [Copyright &y& Elsevier]

Abstract: The paper deals with the theoretical modelling of the high performance Integrated Electro-Hydraulic Actuator (IEHA) introduced in the first part of this work. Based of the hydraulic and dynamic equations, we carried out an analysis of the IEHA input/output relation. A simulation based on this input/output model is detailed showing the ability to access several time derivatives of the payload position mainly its “jerk”, which represents an important issue whenever motion control is considered. We show the theoretical dynamic properties of the proposed solution through open and closed loop simulation results based on Matlab-Simulink. A comparison between the theoretical and experimental results obtained by a built prototype is given in order to demonstrate the promising performances of the proposed solution. [Copyright &y& Elsevier]

Electro-hydraulic actuators have witnessed significant development over recent years due to their remarkable abilities to perform complex and dynamic movements. Integrating such an actuator in humanoids is highly beneficial, leading to a humanoid capable of performing complex tasks requiring high force. This highlights the importance of safety, especially since high power output and safe interaction seem to be contradictory; the greater the robot's ability to generate high dynamic movements, the more difficult it is to achieve safety, as this requires managing a large amount of motor energy before, during, and after the collision. No matter what technology or algorithm is used to achieve safety, none can be implemented without a stable control system. Hence, one of the main parameters remains the quality and reliability of the robot's control architecture through handling a huge amount of data without system failure. This paper addresses the development of a stable control architecture that ensures, in later stages, that the safety algorithm is implemented correctly. The optimum control architecture to utilize and ensure the maximum benefit of electro-hydraulic actuators in humanoid robots is one of the important subjects in this field. For a stable and safe functioning of the humanoid, the development of the control architecture and the communication between the different components should adhere to some requirements such as stability, robustness, speed, and reduced complexity, ensuring the easy addition of numerous components. This paper presents the developed control architecture for an underdeveloped electro-hydraulic actuated humanoid. The proposed solution has the advantage of being a distributed, real-time, open-source, modular, and adaptable control architecture, enabling simple integration of numerous sensors and actuators to emulate human actions and safely interact with them. The contribution of this paper is an enhancement of the updated rate compared to other humanoids by 20% and by 40 % in the latency of the master. The results demonstrate the potential of using EtherCAT fieldbus and open-source software to develop a stable robot control architecture capable of integrating safety and security algorithms in later stages. [ABSTRACT FROM AUTHOR]

This paper presents a new hydraulic robotic leg for the humanoid hydraulic robot HYDROïD. The main parts of this leg are divided into two main parts; the knee subsystem and the ankle subsystem. The presented leg mechanism consists of 4 DOFs, all of which are operated using highly dynamic servo valves. The design of the leg is thoroughly presented and all of its parts are demonstrated. Moreover, the inverse kinematics for both sub-mechanisms are presented to be able to control the angular position of the leg joints. Also, a virtual dynamic model is introduced in which a position controller is applied to the model to regulate the actuating pistons, check the new structure, and analyze the position of the joints and their torques. To test the new leg experimentally, the new leg is assembled with the rest of the robot, and rapid prototyping software is used with a position controller. Experimental position tracking responses are introduced showing the validity of the new design and the implemented controller. [ABSTRACT FROM AUTHOR]