design-implementation-bespoke-robotic-manipulator-for-extra-corporeal

Design and Implementation of a Bespoke Robotic Manipulator for Extra-corporeal Ultrasound

With the potential for high precision, dexterity, and repeatability, a self-tracked robotic system can be employed to assist the acquisition of real-time ...

King's College London

We describe a novel approach for the localization of tissue abnormalities during minimally invasive surgery using a force-sensitive wheeled probe. The concept is to fuse the kinaesthetic information from the wheel-tissue rolling interaction into a pseudocolor rolling mechanical image (RMI) to visualize the spatial variation of stiffness within the internal tissue structure. Since tissue abnormalities are often firmer than the surrounding organ or parenchyma, a surgeon then can localize abnormalities by analyzing the image. Initially, a testing facility for validating the concept in an ex vivo setting was developed and used to investigate rolling "wheel-tissue" interaction. A silicone soft-tissue phantom with embedded hard nodules was constructed to allow for experimental comparison between an RMI and a known soft-tissue structure. Tests have also been performed on excised porcine organs to show the efficacy of the method when applied to biological soft tissues. Results indicate that the RMI technique is particularly suited to identifying the stiffness distribution within a tissue sample, as the continuous force measurement along a given rolling trajectory provides repeatable information regarding relative variations in the normal tissue response. When compared to multiple discrete uniaxial indentations, the continuous measurement approach of RMI is shown to be more sensitive and facilitates coverage of a large area in a short period of time. Furthermore, if parametric classification of tissue properties based on a uniaxial tissue indentation model is desirable, the rolling indentation probe can be easily employed as a uniaxial indenter.

Rolling mechanical imaging for tissue abnormality localization during minimally invasive surgery.

This paper investigates the use of inverse finite-element modeling (IFEM)-based methods for tissue parameter identification using a rolling indentation probe for surgical palpation. An IFEM-based algorithm is proposed for tissue parameter identification through uniaxial indentation. IFEM-based algorithms are also created for locating and identifying the properties of an embedded tumor through rolling indentation of the soft tissue. Two types of parameter identification for the tissue tumor are investigated (1) identifying the stiffness (μ) of a tumor at a known depth and (2) estimating the depth of the tumor (D) with known mechanical properties. The efficiency of proposed methods has been evaluated through silicone and porcine kidney experiments for both uniaxial indentation and rolling indentation. The results show that both of the proposed IFEM methods for uniaxial indentation and rolling indentation have good robustness and can rapidly converge to the correct results. The tissue properties estimated using the developed method are generic and in good agreement with results obtained from standard material tests. The estimation error of μ through uniaxial indentation is below 3 % for both silicone and kidney; the estimation error of μ for the tumor through rolling indentation is 7-9 %. The estimation error of D through rolling indentation is 1-2 mm.

Inverse finite-element modeling for tissue parameter identification using a rolling indentation probe.

This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor's main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human-robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery) robot, and includes its design, fabrication, and evaluation tests.

Hongbin Liu

Department of Informatics

King's College London

Design and Implementation of a Bespoke Robotic Manipulator for Extra-corporeal Ultrasound

Hongbin Liu

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Informatics

King's College London

Design and Implementation of a Bespoke Robotic Manipulator for Extra-corporeal Ultrasound

Department of Informatics