The question of whether and how aging affects humans’ visuomotor adaptation remains controversial. This study investigates how the effect of aging on visuomotor adaptation is related to age-related cognitive declines. We compared the performance of 100 older people (age: 55–82 years) and 20 young adults (age: 18–27 years) on a visuomotor adaptation task and three cognition tasks. A decline in visuomotor adaptation of older people was well observed. However, this decline was not strongly correlated with chronological age increase but was associated to the age-related declines of cognitive functions and speed of motor planning. We then constructed a structural mediation model in which the declined cognitive resources mediated the effect of age increase on the decline in visuomotor adaptation. The data from the present study was well-explained by the mediation model. These findings indicate that the aging effect on visuomotor adaptation mainly reflects the age-related decline of cognitive functions, which results in insufficient explicit processing on visual perturbation during visuomotor control.

In this study, an active microvibration isolation system is developed for precision space payload. Vibrational environment affects the performance and reliability of measuring instruments. To improve the measurement accuracy of the precision space payload, an active vibration isolation system based on eight vibration isolation modules, which are applied for microvibration isolation on the satellite, is designed. A vibration suppression control strategy for multiple degrees of freedom is studied. A hybrid control method involving a feedback and a feedforward controller based on a nonlinear tracking differentiator and an nth-order weak integrator, respectively, was adopted to optimize the suppression effect of microvibration. As a result, the microvibration of the order of mg can be reduced to the order of μg through the active control of modules. Research experiment results show that the root cumulative power spectral density of the systemic sensitive frequency band in the range of 0.5–200 Hz, i.e., microvibration frequency band in the optical reference cavity, has been reduced to in the order of μg in three directions, which satisfied the requirements of aerospace engineering.

The optical reference cavity in an ultrastable laser is sensitive to vibrations; the microvibrations in a space platform affect the accuracy and stability of such lasers. In this study, an active vibration isolation controller is proposed to reduce the effect of vibrations on variations in the cavity length and improve the frequency stability of ultrastable lasers. Based on the decentralized control strategy, we designed a state-differential feedback controller with a linear quadratic regulator (LQR) and added a disturbance observer (DOB) to estimate the source noise. Experiments were conducted using an active vibration isolation system; the results verified the feasibility and performance of the designed controller. The accelerations along the axis (Z-, X-, Y-) directions were suppressed in the low-frequency band within 200 Hz, and the root-cumulative power spectral densities (PSDs) declined to 1.17 × 10−5, 7.16 × 10−6, and 8.76 × 10−6 g. This comprehensive vibration met the requirements of an ultrastable laser.

A spaceborne mounting method for fixing a 100 × 100 × 100 mm cubic Fabry–Pérot (FP) cavity is presented. The method constrains the FP cavity in eight directions with a titanium bracket, PEEK gaskets, and vacuum glue. Three criteria were proposed for judging whether the FP cavity is offset or not during aerospace vibration tests. Results indicate that the proposed method is a reliable, robust, and stable way to fix a cubic FP cavity in ultra-stable lasers (USLs). This approach paves the way for the use of USLs in space.

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