SUMMARY The soft actuator is made of superelastic material and embedded flexible material. In this paper, a kind of soft tube was designed and used to assemble two kinds of pneumatic soft actuators. The experiment and finite element analysis are used to comprehensively analyze and describe the bending, elongation, and torsion deformation of the soft actuator. The results show that the two soft actuators have the best actuation performance when the inner diameter of the soft tube is 4 mm. In addition, when the twisting pitch of the torsional actuator is 24 mm, its torsional performance is optimized. Finally, a device that can be used in the production line was assembled by utilizing those soft actuators, and some operation tasks were completed. This experiment provides some insights for the development of soft actuators with more complex motions in the future.

Because the current actuator assemblies in hard disk drives (HDDs) are flexible systems, the resonant modes of the system inevitably limit its servo control bandwidth, which in turn limits the aerial density growth of HDDs, and also its shock robustness especially when HDDs are being increasingly deployed for consumer applications. The design and analysis method of a dynamic absorber to improve dynamic properties and shock resistance of HDDs is presented in this article. The HDD and the attached absorber were established and modeled as a 2 degrees-of-freedom (2DOF) system. The design parameters and structural configuration of the damping device, which is suitable for HDDs under base excitation, have been specified. Theoretical studies on the dynamic characteristics and shock resistance of the actuator assembly of the HDDs with attached dynamic absorbers have been described. The effectiveness of the dynamic absorber and the adopted design procedure are illustrated from the point of view of both bandwidth improvement and shock protection capacities. It has been clearly demonstrated that the introduction of a dynamic absorber into the actuator arm system, if properly designed, can greatly improve the capabilities of shock handling and residual vibration suppression in either operating or nonoperating conditions of HDDs.

Based on derivation of fluid inertia velocity distribution, the paper proposes an analytical model for pressure distribution of squeeze film damper (SFD) in long bearing assumption under impact loading. Compared with numerical simulation and test results, the model is reasonable. The model analysis results reflect the reversion behavior about SFD radial force. Therefore, a design rule of synchro-response for SFD is recommended, and then an expression of SFD parameters is given which is in accordance with the rule. These results are useful for design and for real-time active control of SFD-rotor-system, and are helpful for further theoretical investigation on oil film dynamic behavior also.

No abstract