A continuum manipulator with phase changing alloy

Abstract

A new type of cable-driven continuum manipulator (CM) is presented, in which the stiffness of the device along its body length can be controlled using the thermomechanical properties of a phase changing alloy. The liquid phase of the alloy is used for achieving high dexterity and the solid phase for high stiffness. Joule heating and water cooling is used for transitioning the phase changing alloy between stiff and compliant states. Single-segment and two-segment working prototypes of the CM are demonstrated. The mechanical and thermodynamic features of these prototypes are discussed and their physical performance is investigated. Advantages of the presented design with phase changing alloy include: significantly improved dexterity, high payload to weight ratio, controllable stiffness, energy efficiency, and a large lumen.

A Geometry Deformation Model for Braided Continuum Manipulators

“…However, as the manipulator becomes softer and the cross-section diameter to the module length ratio increases, the cross-section deformation becomes more important. This cannot be neglected in case of emerging studies on embedding regional stiffness-tunable structures in continuum manipulators (Alambeigi et al, 2016;Meerbeek et al, 2016;Shiva et al, 2016).…”

“…Different mechanisms to control soft robot stiffness for safe interaction and minimally invasive applications are gaining increasing interest recently. To this end, stiffness-tuneable structures by granular jamming (Steltz et al, 2010;Jiang et al, 2012;Ranzani et al, 2015) and low-melting point alloys (Cheng et al, 2014;Alambeigi et al, 2016), morphing structures (Kuder et al, 2013), stiffness controllable interfaces by granular (Follmer et al, 2012;Stanley et al, 2016), layer (Kim et al, 2013), and scale jamming (Hadi Sadati et al, 2015;Santiago et al, 2016) are recently investigated. The new interest in the continuum manipulators with stiffness varying and inhomogeneous compound structures indicates the need for further investigation of their modeling and control problems.…”

A variable‐stiffness continuum manipulators by an SMA‐based sheath in minimally invasive surgery

“…Intelligent materials like magnetorheological (MR) or electrorheological (ER) fluids are focused on due to their variable physical properties . Phase change materials, such as paraffin, solder, thermoplastic polymers, and low melting point liquid metal (LMPA), have become a new research hotspot . In spite of the fact that experiments have demonstrated a wide range of changes in stiffness and strength for phase change materials, most phase change materials have a relatively longer activation timescale compared with others.…”

“…[6][7][8] Phase change materials, such as paraffin, solder, thermoplastic polymers, and low melting point liquid metal (LMPA), have become a new research hotspot. [9][10][11] In spite of the fact that experiments have demonstrated a wide range of changes in stiffness and strength for phase change materials, most phase change materials have a relatively longer activation timescale compared with others. In addition, granular jamming technology based on granular media has recently been focused on in the field of variable stiffness.…”

Approximating Markov Chain Approach to Optimal Feedback Control of a Flexible Needle

“…Advancements in robotic minimally invasive surgeries have extended its applications to a variety of the diagnostic and therapeutic tasks. In addition to the sophisticated design and fabrication of surgical tools [1][2][3][4][5], estimation [6][7][8], motion planning, and control [9][10][11][12][13][14][15] of the surgical tool tip are crucial problems in many of such procedures. Particularly, in the needle biopsies and drug injections, bevel tip of the needle along with its flexibility allows for driving the needle through a curved trajectory.…”