This paper deals with the problem of reliable guaranteed cost control for linear descriptor time-delay systems with actuator failure. The actuator failure mold adopted in this paper is in complete form to describe variation of the actuator. To design a controller such that, for admissible actuator failures, the plant remains asymptotically stable and guarantees an adequate level of a quadratic ...

A high redundancy actuator (HRA) is composed of a high number of actuation elements, increasing both the travel and the force over the power of an individual element. This provides inherent fault tolerance, because when an element fails, the capabilities of the actuator may be reduced, but it does not become dysfunctional. This paper analyses the likelihood of different reductions in capabiliti...

This paper presents a low-profile bidirectional folding actuator based on annealed shape memory alloy sheets applicable for mesoand microscale systems. Despite the advantages of shape memory alloys—high strain, silent operation, and mechanical simplicity—their application is often limited to unidirectional operation. We present a bidirectional folding actuator that produces two opposing 180 mot...

The optimization of trajectories and actuator torques for a dual arm manipulation system is considered. Given the starting and nal conngurations, we nd the trajectories that minimize (a) the integral of the norm of the vector of derivatives of the actuator forces; and (b) the integral of the norm of the actuator forces. In this way both kinematic and actuator redundancy are resolved. The optimi...

This paper deals with a recently developed actuator based on piezoelectric bimorphs which are useful for ASAC applications. The actuator takes the form of two channels with pairs of bimorphs. Each of the bimorph transducers in the couple is connected separately so that the actuator can act in both moment and force configurations simultaneously. The control algorithm allows the ratio between the...

This paper presents a new type of muscle-like actuator, namely double-acting (DA) sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc.). Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert a...

This paper presentsan adaptive actuator failure compensation method, which compensates for uncertainties due to unknown actuator failures for redundant manipulator systems. The method is first developed for manipulators whose joints are concurrently actuated. While physical realization of concurrently actuated manipulators and the advantages of their use have been understood before, in this pap...

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A linear piezoelectric actuator based on the stick-slip principle is presented and tested in this paper. With the help of changeable vertical preload force flexure hinge, the designed linear actuator can achieve both large travel stick-slip motion and high-resolution stepping displacement. The developed actuator mainly consists of a bridge-type flexure hinge mechanism, a compound parallelogram ...