In this contribution we present the novel electro-pneumatic adaptable impedance actuator (EPAIA) consisting of a brushless DC-motor and a rotational pneumatic actuator, applied in series to the gear train. The pneumatic actuator is employed as a pneumatic torsional spring with a continuously adaptable stiffness, controlled by air inflow and pressure control. Thus, a rotary variable stiffness ac...

An actuator is required to change its speed and force depending on the situation. Using multiple actuators for one driving axis is one of the possible solutions; however, there is an associated problem of output power matching. This study proposes a new active joint mechanism using multiple actuators. Because the actuator is made of a flexible bag, it does not interfere with other actuators whe...

The Inertially Stabilized Rifle is a new stabilized rifle system that can eliminate the disturbances induced by the shooter. Recurve actuator is used in this system to provide the precise movement of the rifle barrel. In such a portable device, only low voltage electrical sources are available yet the piezoelectric actuator needs high voltage to drive the actuator. The actuators consume little ...

A better understanding of how actuator design supports locomotor function may help develop novel and more functional powered assistive devices or robotic legged systems. Legged robots comprise passive parts (e.g., segments, joints and connections) which are moved in a coordinated manner by actuators. In this study, we propose a novel concept of a hybrid electric-pneumatic actuator (EPA) as an e...

Abstract: This paper presents a general framework for model-based fault detection and accommodation for a class of distributed parameter systems with control actuator faults. A set of dedicated observers, each with its own time-varying threshold is constructed to detect the occurrence of fault in the corresponding actuator and reduce fault detection time. Additionally, an adaptive diagnostic ob...

We have evaluated the ability of three commercially available deformable mirrors to compensate the aberrations of the eye using a model for aberrations developed by Thibos, Bradley and Hong. The mirrors evaluated were a 37 actuator membrane mirror and 19 actuator piezo mirror (OKO Technologies) and a 35 actuator bimorph mirror (AOptix Inc). For each mirror, Zernike polynomials and typical ocula...

By combining the disciplines of control design, condition monitoring and fault detection identification and accommodation, it should be possible to provide actuators that possess: consistent and tuneable closed-loop performance, a tolerance to sensor faults and the ability to detect actuator deterioration early. This will lead to improved reliability and availability of the actuator. This paper...

The power density and variable compliance in pneumatic actuators makes them an attractive option for actuation in human assistive devices. Interaction safety in these devices can be robustly achieved through energetically passive controllers. Efficacy of these controllers depends on appropriate definition of actuator energy function. In previous works, the energy function was defined by assumin...

This paper presents the development of an integrated reconfigurable control allocation approach. This integrated approach combines frequencyapportioned control allocation with actuator failure detection and isolation. Frequency-apportioned control allocation integrates innovative control effectors with conventional aerodynamic controls and considers both the steady-state performance and frequen...

In this paper a method for piezoelectric stack actuator control is proposed. In addition a brief discussion about the usage of the same methods for estimation of external force acting to the actuator in contact with environment is made. The method uses sliding mode framework to design both the observer and the controller based on an electromechanical lumped model of the piezoelectric actuator. ...