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. ...

The crosstalk characteristic is a key factor that affects the pickup actuator dynamic property and consequently the accuracy of reading and writing operation in the future ultra-high density optical storage systems. In this paper, the actuator spatial magnetic field distribution model is first established. Then the crosstalk movement phenomenon of the actuator is analyzed and simulated in CST s...

Scissor lifts, a staple of mechanical design, especially in competitive robotics, are a type of linkage that can be used to raise a load to some height, when acted upon by some force, usually exerted by an actuator. The position of this actuator, however, can affect the mechanical advantage and velocity ratio of the system. Hence, there needs to be a concrete way to analytically compare differe...

An improved version of the membrane actuator has been designed and constructed based on our previous diaphragm actuator. It consists of ferromagnetic shape memory alloy composite (FSMA) diaphragm and an electromagnet system. The actuation mechanism of the membrane actuator is the hybrid mechanism that we proposed previously. The high momentum airflow will be produced by the oscillation of the c...