Compliance and control characteristics of an additive manufactured-flexure stage

Abstract

This paper presents a compliance and positioning control characteristics of additive manufactured-nanopositioning system consisted of the flexure mechanism and voice coil motor (VCM). The double compound notch type flexure stage was designed to utilize the elastic deformation of two symmetrical four-bar mechanisms to provide a millimeter-level working range. Additive manufacturing (AM) process, stereolithography, was used to fabricate the flexure stage. The AM stage was inspected by using 3D X-ray computerized tomography scanner: air-voids and shape irregularity. The compliance, open-loop resonance peak, and damping ratio of the AM stage were measured 0.317 mm/N, 80 Hz, and 0.19, respectively. The AM stage was proportional-integral-derivative positioning feedback-controlled and the capacitive type sensor was used to measure the displacement. As a result, the AM flexure mechanism was successfully 25 nm positioning controlled within 500 μm range. The resonance peak was found approximately at 280 Hz in closed-loop. This research showed that the AM flexure mechanism and the VCM can provide millimeter range with high precision and can be a good alternative to an expensive metal-based flexure mechanism and piezoelectric transducer.

Positioning control effectiveness of optical knife edge displacement sensor-embedded monolithic precision stage

“…It was thought that the error is due to PID gain mismatching as well as the hysteresis and non-linearity of the VCM. In previous research [25], the AM flexure stage was position feedback controlled by using CF, and the hysteresis characteristics of the AM flexure mechanism were discussed. The maximum hysteresis error (difference between loading and unloading conditions) was approximately 20μm for CS-based control systems.…”

“…In Figure 2, A x and A y are the length of the hinge, T is the thickness of the hinge, B is the width of the hinge, L is the length of the flexure and H is the height of flexure. Based on finite element method analysis of the proposed flexure [25], the design parameters of the flexure were set as follows: H=1.0mm, B=15.0mm, L=20.0mm. The maximum flexure stage deflection was estimated 4.125mm at 10N.…”

“…The flexure mechanism was designed in a double compound notch-type with hinges [3]. Each spring was designed with circular flexure hinges at both ends as shown in Figure 2.These hinges are commonly used in compliant micro-motion stages which required high precision of motions [3,5,[25][26][27]. In Figure 2, A x and A y are the length of the hinge, T is the thickness of the hinge, B is the width of the hinge, L is the length of the flexure and H is the height of flexure.…”

Fabrication, Experiments, and Analysis of an LBM Additive-Manufactured Flexure Parallel Mechanism

“…In the existing literature, many researchers have developed prototypes of flexure mechanisms through 3D printing using plastic materials due to their widespread use both in academia and industry [ 11 , 12 ]. However, plastic products suffer disadvantages such as low stiffness, short strength life, and creep deformation, which limit their application in engineering [ 13 ].…”

X-ray computed tomography for additive manufacturing: a review

“…The authors performed morphological deviation and defect analyses in comparison to nominal CAD designs. In the paper that followed, Lee and Tarbutton [105] described the final results of their work and concluded through testing of the flexure stage that their method was capable of producing a cost-effective alternative to other similar stages, achieving 25 nm positional precision over a 500 m range.…”