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In this paper a recursive algorithm for robustly stabilizing an uncertain gained controlled polynomial with affine linear coefficients, is presented. The finite step algorithm is constructed using the results of Hurwitz invariability and the respective results of simulated annealing tuning techniques. The algorithm is appropriately modified expanding the search horizon of previous algorithms aiming...
There are many controllers in the force control of the electro-hydraulic actuator. However they have a limitation of the performance and the application. In this study, to apply the iterative control to the force control, the iterative control strong to nonlinearity of the system was investigated. The role of the learning factor, a gain that make the iterative control strong to nonlinearity, was argued...
A novel nonlinear function parameterization model was proposed for nonlinear adaptive controller design. This approach re-parameterizes the nonlinear function with unknown parameters linearly, which simplifies the adaptive controller design significantly. A recently developed passivity based backstepping controller using a physical compressibility energy function for a chamber hydraulic cylinder was...
Hydraulic actuators are characterized by fast dynamics, high power density, high stiffness, large output force/torque, and in recent years are becoming increasingly attractive in the field of robotics. This paper presents the study of a 3-way proportional valve controlled, spring assisted electro-hydraulic rotary actuator, which consists of a 3-way proportional valve, a linear cylinder and a reciprocal...
This paper is concerned with the application of switching technology to hydraulic actuation. Over the last 50 years with advances in power electronics, faster and faster static switches have been developed and applied to the control of motors. Hydraulic technology evolved in the opposite direction: switching control was not considered, and more and more accurate proportional flow/pressure control...
An excitation means of electrohydraulic vibrator is proposed and aimed to enhance the working frequency. The vibrator is a symmetrical hydraulic cylinder controlled by a 2D valve, in which both rotary and linear motions of a single spool are used to vary the frequency and the amplitude independently. The frequency of the vibrator is proportional to the rotary speed of the spool and thus the high-frequency...
A newly developed hand rehabilitation system is presented that combines robotics and interactive gaming to facilitate repetitive performance of task specific exercises for patients recovering from neurological motor deficits. A two degree of freedom robotic interface allows coordinated motions of the forearm and the hand (pronation/supination and grasp/release, respectively). It is driven by two novel...
This paper is focussed on the modelling and control of a hydraulically-driven biologically-inspired robotic leg. The study is part of a larger project aiming at the development of an autonomous quadruped robot (hyQ) for outdoor operations. The leg has two hydraulically-actuated degrees of freedom (DOF), the hip and knee joints. The actuation system is composed of proportional valves and asymmetric...
A new piezoelectric/ electrorheological hybrid hydraulic ultra-precision step actuator that uses a hybrid mode of piezoelectric stack pump hydro-drive and electrorheological valve control to the precision hydraulic cylinder is presented. It achieves high frequency, ultra-precision hydraulic step drive. The working principle of the step actuator is analyzed and its experimental characteristics are...
In the deep-drawing process of sheet metal, accuracy, consistency and formability of products always determined by the variable blank holder force (VBHF). So, the accuracy of predicted reference input VBHF curves, the response performance of hydraulic actuators, and the tracing performance of machine controller are key technologies which determine the control performance of VBHF. Firstly, outline...
A new type of diphase oppositing giant magetostrictive self-sensing actuator force-feedback water hydraulic servo valve is introduced, including its structure and working principle. The electro-mechanical convert model of the diphase oppositing magetostrictive self-sensing actuator is established, based on this, the mathematical model of the servo valve is constructed. The static output characteristics...
In order to expedite calibrations of force measuring instruments, variable speed control of linkage-weight stacks has been newly introduced to the 540 kN dead-weight type force standard machine (DWM) of the National Metrology Institute of Japan. In contrast with actuators driven by AC servo motors which are adopted in DWMs of relatively small capacities, the hydraulic actuator required more gradual...
This paper presents a novel design for demand dependent active suspension (DDAS) focusing on vehicle rollover control. Active suspensions take credit for improving ride comfort and handling performance, but to use active suspension in vehicle rollover control has not been widely investigated. The proposed active suspension design consists of four double direction hydraulic actuators, hydraulically...
In this article, an optimal control scheme for a piezo- hydraulic actuator exploiting resonance effects is presented. The proposed actuator relies its operation on the significant pressure built up in a fluid pipe during resonance. The actuator's piston houses a valve which rectifies the wave's motion into direct mechanical motion. The discretization of the partial differential equation from the compressible...
This paper presents an approach for design and control of a new servo valve which has variety of applications such as in vehicle active suspension system. The new setup which is referred to as Nitinol-hydraulic actuator consists of a smart spool rod covered by smart materials for operating position assigning of inlet and outlet ports. Inter-metallic compound of Nitinol (Ni-Ti) is used for actuator...
The novel electrohydraulic vibration exciter consists of two-dimension servo control valve (abbr.2D valve) and double acting hydraulic cylinder. Vibration frequency and amplitude of electrohydraulic vibration exciters are controlled by the rotation and linear motion of the 2D valve spool respectively. The frequency of the 2D valve controlled vibration exciter is determined by the rotary speed and...
This communication deals with the key issues of a hybrid actuation system operating in active/no-load mode. The hybrid actuation system under study is made of a servo valve controlled hydraulic actuator (SHA) and an electro-mechanical actuator (EMA). In active/no-load mode, both actuators are actively controlled; the SHA is in position control while the EMA is controlled to generate null force. Virtual...
A multi-fingered robotic hand is developed using hydraulic actuation with fluidic actuators. A miniaturised hydraulic system is designed with all components intrinsically placed inside the palm. All finger parts of the prototype are integrated into a single unit and constructed from two part urethane mould, which is a very flexible material. Fourteen finger joints with 14 DOF are powered by fluidic...
A new concept of diphase oppositing giant magnetostrictive self-sensing actuator is put forward, combining with sea water servo control technology, a flapper-nozzle force feedback sea water servo control valve is designed. Bridge analysis model based on variable inductance is established, dynamic balance separation technology for giant magnetostrictive self-sensing actuators is come true by least...
A method of robust control combined with compensation of feed-forward load force and feedback friction is presented to reduce the motion vibration of 6-DOF (six degree-of-freedom) hydraulic parallel robot. A mathematic model for the asymmetric hydraulic actuator controlled by symmetric valve is established and a Lugre friction observer is designed. The observed friction and ideal load force computed...
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