A Minimal POE-Based Model for Robotic Kinematic Calibration With Only Position Measurements

Abstract

This paper proposes an algorithm for robotic kinematic calibration based on a minimal product of exponentials (POE)-based model for the applications where only position measurements are required. Both joint zero-offset errors and initial frame twist error can be involved in this model. Analysis of the identifiability of these errors shows that at most six elements of these parameters can be identified. It also suggests that at least three noncollinear points on the end-effector should be measured to maximize the identifiability. Compared with the traditional POE-based model with full pose (position and orientation) measurements, the minimal model with only position measurements outperforms in terms of convenience, efficiency, and accuracy.

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Towards Occlusion-Free Surgical Instrument Tracking: A Modular Monocular Approach and an Agile Calibration Method

Abstract

Optical means of instrument tracking has been widely used in image-guided interventions and considered the de facto standard for tracking rigid bodies with a direct line-of-sight. However, the occlusion problem which remains unresolved in current systems frustrates surgeons during the operation. To address this challenge, we propose a surgical instrument tracking system based on multiple reconfigurable monocular modules. The main approach is to enable the system to dynamically reconfigure the multiple monocular modules when occlusion occurs partially within the workspace. In this paper, we focus on the system architecture and an agile multicamera calibration method which only uses the customized tool for the surgical instrument tracking scenario. Additionally, two fast non-iterative algorithms are proposed and studied. In order to show the feasibility and superiority of the corresponding multicamera calibration algorithm, comparison experiments have carried out. The intensive investigation results give a practical instruction to the real implementation of the proposed system in image-guided interventions

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NUS S&T Exhibition Launch at UCC

(9 April 2015) We have been invited to demonstrate our Intelligent Tubular Robotic System (iTubot) at the exhibition showcasing NUS’ contribution to nation-building through groundbreaking research. The event launched at the University Cultural Centre on 9 April to celebrate the 50th birthday of Singapore and the 110th birthday of NUS.

Our Intelligent Tubular Robotic System can potentially assist with minimally invasive procedures and is also endowed with intelligent navigation capabilities, which receives much attention during the event.

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Nonlinear Fuzzy Linguistics for the Determination of Nitrogen Monoxide, Nitrogen Dioxide, and Sulfur Dioxide by Molecular Absorption Spectroscopy

Abstract

The nonlinearity and high dimensionality of spectra affect the precision and the complexity of molecular absorption spectroscopy models. This paper reports a nonlinear fuzzy linguistic method for spectroscopic quantitative analysis. A nonlinear fuzzy linguistic rule is presented. In the rule antecedent, a set operation was used to express the input variables and the fuzzy linguistic terms. A flexible polynomial equation of the input variables was a consequential rule. The fuzzy linguistic terms, the membership functions, and the nonlinear linguistic rules were initialized automatically by Gaussian kernel fuzzy clustering analysis, and the related parameters of nonlinear fuzzy linguistic rules were tuned by the iterative optimization for minimizing the root-mean square error. The principal components of the absorption measurements were extracted as input variables to reduce the complexity of the model. Experimental measurements employed a spectral dataset of flue gas for quantitative determination of the components that included sulfur dioxide, nitric oxide, and nitrogen dioxide. The experimental results verify the effectiveness of the theoretical approach.

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A Novel Tele-Operated Flexible Robot Targeted for Minimally Invasive Robotic Surgery

Abstract

In this paper, a novel flexible robot system with a constrained tendon-driven serpentine manipulator (CTSM) is presented. The CTSM gives the robot a larger workspace, more dexterous manipulation, and controllable stiffness compared with the da Vinci surgical robot and traditional flexible robots. The robot is tele-operated using the Novint Falcon haptic device. Two control modes are implemented, direct mapping and incremental mode. In each mode, the robot can be manipulated using either the highest stiffness scheme or the minimal movement scheme. The advantages of the CTSM are shown by simulation and experimental results.

A Novel Tele-Operated Flexible Robot… (PDF Download Available). Available from: https://www.researchgate.net/publication/281389458_A_Novel_Tele-Operated_Flexible_Robot_Targeted_for_Minimally_Invasive_Robotic_Surgery [accessed May 30 2018].
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Two projects won awards from Asia Pac AR&TTs challenge 2015

(Mar, 2015) In the recent Asia Pac AR&TTs challenge 2015, our project on a soft robotic system for oral intervention (team members: Neera, Yi, Hongliang) won the Commercial Potential Award and the project on magnetic actuated robotic intervention (team members: Shen Shen, Zhu Jingling, Song Shuang, Li Jun, Loh Kai Ting, Ren Hongliang) won the Pitching Award.

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