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International audience; 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 ac-tuating 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.

International audience; High-pressure consumption during locomotion has been always a major drawback in using hydraulic humanoids. In the framework of the hydraulic humanoid robot HYDROïD, this paper aims to provide a methodology of energy consumption reduction for a hydraulic ankle mechanism. The design of the new integrated hybrid parallel ankle mechanism is presented. High-performance hydraulic servo vales are used for position control of the ankle joints. Besides, hydraulic integration technology is implemented on the mechanism to provide further decreases in leakage and slimmer shape. The parallel solution is chosen to provide the required ankle joints motions without affecting the compact shape of the leg. Four pistons are placed in a parallel way, where the two antagonists and agonists work together as a couple in order to emulate the muscles of the human ankle. A comprehensive study is done on the mechanism design in order to provide the least possible pressure consumption without affecting the output ankle torque. In order to verify the newly generated ankle torque, a locomotion study for the ankle mechanism is provided to ensure the locomotion capability of the new mechanism. Additionally, the new hybrid design is validated experimentally using a MATLAB/Simulink-based position controller for the ankle joints. The new experimental results have showed the validity of the design, controller, and optimized pressure consumption. The new design has been able to achieve a pressure enhancement of 30% in comparison with the old design. © 2022 Praise Worthy Prize S.r.l.-All rights reserved.

The invention relates to a hydraulic actuator comprising a variable-output positive-displacement pump (12), a member (20) allowing the output of the pump (12) to be varied continuously, the member (20) being actuated by a cylinder (40) fed from a first directional-control valve (48) operated according to a command controlling the movement of the actuator (10). According to the invention, the actuator (10) comprises a second directional-control valve (60) controlled according to an output pressure (P) of the pump (12), the second directional-control valve (60) having two positions, one of them (60a), known as the rest position, being obtained as long as the output pressure (P) of the pump (12) is below a predetermined pressure and transmitting the output from the first directional-control valve (48) to the double-acting cylinder (40), and the other (60b), known as the active position, transmitting the output pressure (P) of the pump (12) to the cylinder (40) in such a way as to reduce the output pressure (P) of the pump (12) without passing via the first directional-control valve (48)., L'invention concerne un actionneur hydraulique comprenant une pompe (12) volumétrique à débit variable, un organe (20) permettant de faire varier en continu le débit de la pompe (12), l'organe (20) étant actionné par un vérin (40) alimenté par un premier distributeur (48) commandé en fonction d'un ordre de déplacement de l'actionneur (10). Selon l'invention, l'actionneur (10) comprend un deuxième distributeur (60) commandé en fonction d'une pression de sortie (P) de la pompe (12), le deuxième distributeur (60) comprenant deux positions, l'une (60a) dite repos obtenue tant que la pression de sortie (P) de la pompe (12) est inférieure à une pression prédéterminée et transmettant la sortie du premier distributeur (48) au vérin double effet (40) et l'autre (60b) dite active, transmettant la pression de sortie (P) de la pompe (12) au vérin (40) de façon à réduire la pression de sortie (P) de la pompe (12) sans passer par le premier distributeur (48).

Daily activities are a source of fatigue and stress for people with lower extremity spasticity. The possible aids must be introduced while maintaining priority control by the patient. This work aims to develop such an application in the context of walking on the exoskeleton developed at the Systems Engineering Laboratory of Versailles (LISV). The application results are based on data recorded at the END-ICAP laboratory with gait sensors for healthy subjects, people with CPs, and people who had a stroke. Our contribution is the proposal of a new method of neuromotor control for a rehabilitative exoskeleton. It consists in determining and assisting the motor instructions for the movements of a patient while retaining his expertise; the assistance as needed and the detection of its intention based on a fusion of information. The results show that the proposed index characterizes the relationship of the angle difference with a reference movement for each joint. It dynamically compensates for movements efficiently and safely. This index is applicable for gait pathology studies and robotic gait assistance.