# Development of a Piezoelectric-Driven XYθz Nano-Positioning Stage with High Load-Bearing Capacity Enabled by Over-Constrained Guiding Configuration

## TL;DR

A new nano-positioning stage with high load-bearing capacity is developed using an over-constrained guiding configuration for precise three-axis motion.

## Contribution

The novel over-constrained XYθz nano-positioning stage with enhanced load-bearing and anti-deformation capabilities is introduced.

## Key findings

- The stage achieves a motion range of up to 152.22 μm × 151.3 μm × 2.885 mrad.
- It maintains anti-deformation capability of 200 nm under 4 kg loading.
- Hybrid amplification mechanisms improve displacement output and structural stiffness.

## Abstract

A novel over-constrained XYθz nano-positioning stage with a high load-bearing capacity is proposed. This serially connected displacement stage adopts an embedded structural design that integrates a translation stage with a rotation stage in series. The Z-axis amplification mechanism employs out-of-plane actuation, realising a compact solution for three-axis independent motion. The hybrid amplification mechanism designed in the translation stage ensures enhanced output displacement and structural stiffness. The hybrid-parallel amplification mechanism comprises a lever-type displacement amplifier and a Scott–Russell displacement amplifier connected in series, which is then connected in parallel with a bridge-type displacement amplifier. An over-constrained mechanism is introduced to impose redundant constraints along the Z-axis, effectively suppressing parasitic displacement in the Z-direction while enhancing resistance to out-of-plane deformation. A quasi-static model of the XYθz motion stage was established to comprehensively characterise the deformation behaviour of the stage, which was verified by finite element simulations and experiments on the prototype. The experimental results indicate that the XYθz stage achieves a large motion range (up to 152.22 μm × 151.3 μm × 2.885 mrad) while maintaining excellent anti-deformation capability 200 nm at 4 kg loading.