The work presented in this paper is based on a novel integrated and compact hydraulic robotic actuator [1] (BIA patentUS20110085922), intended for the hydraulic humanoid robot HYDROïD. This actuator solves the problem of autonomy for hydraulic humanoid robots as it can be integrated to operate each joint separately. Thus, eliminating the need for a central hydraulic power pack. Also, due to its...

Impedance control of a hydraulic servoactuator joint system is discussed in this paper. Impedance control imparts a desired behavior to a system, rather than it controls position or force individually. Due to nonlinear properties of hydraulic actuators, impedance control is difficult. The control strategy presented here involves a combined feedforward and feedback control. An impedance filter m...

For a quadruped robot with 12 active joints driven by linear hydraulic actuators, some important parameters, such as the oil flow of the hydraulic system and the needed maximum output force of each actuator, are hard to calculate precisely with kinematics and dynamics equations. The oil flow is mainly determined by the walking speed of the quadruped robot, but also influenced by the stride freq...

Parallel manipulators have advantages such as high stiffness, low moving inertia, high payload capability, and high accuracy. In this paper, the servo drive system of valve controlled asymmetrical hydraulic cylinder is designed for 4SPS/S parallel manipulator with redundant actuator. A unified nonlinear model suitable for forward and inverse motion is deduced for the valve controlled asymmetric...

The positioning accuracy of conventional servo hydraulic cylinders is limited by oil compressibility, leak oil, nonlinearities, hysteresis effects, etc. This affects the control quality of the actuator, which is essential for a use in high dynamic positioning tasks, such as applications in active damping systems for machine tools. The presented hydraulic actuator design is a new approach to ext...

Hydraulic actuator has been widely used in industrial applications due to its fast response and capability of moving heavy load. The nonlinear properties of hydraulic cylinder had challenged researchers to design a suitable controller for position control, motion control and tracking control. Based on these problems, we had done a real-time digital tracking control studies on electrohydraulic c...

Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a serie...

joint flexibility is a very important factor to consider in the controller design for robot manipulators if high performance is expected. most of the research works on control of flexible-joint robots in literature have ignored the actuator dynamics to avoid complexity in controller design. the problem of designing nonlinear controller for a class of single-link flexible-joint robot manipulator...

In this paper, reinforcement learning is applied to coordinate, in a decentralized fashion, the motions of a pair of hydraulic actuators whose task is to firmly hold and move an object along a specified trajectory under conventional position control. The learning goal is to reduce the interaction forces acting on the object that arise due to inevitable positioning errors resulting from the impe...