Planning of Soft-Rigid Hybrid Arms in Contact With Compliant Environment: Application to the Transrectal Biopsy of the Prostate

Abstract

In this study, a rigid robot is hybridized with a soft part to improve its properties of relative positioning and safe interaction. While the design of the device is quite simple, the kinematics, on the other hand, becomes complex. Pre-operative planning of such a robot is a challenge that is faced in this paper. The clinical context is the automation of transrectal prostate biopsy: a robot is connected to a thin ultrasound (US) probe instrumented with a needle through a flexible silicone part. The procedure consists of: moving the probe near the prostate through the rectum, aligning the probe with identified lesions in the prostate, and shooting the needle to collect tissue samples. In this paper we demonstrate in simulation the feasibility of our methods to solve the planning of the entire procedure. The approach we propose is based on numerical models of both robot and soft tissues, using the Finite Element Method (FEM) to model the soft parts, and a mapping mechanism to propagate the forces and displacements between the soft and rigid models. Finally, we extend the optimization algorithm proposed in previous work for the relative positioning of the hybrid robot on targets in the prostate, as it interacts with the soft tissues. With this formulation we can also set an upper limit to the force the robot is applying on its surroundings, which is particularly critical for the application we study in this paper.

Pioneering healthcare with soft robotic devices: A review

“…Ablation tools and a micro camera with lights were embedded in the central channel of the probe. In another study, planning of a soft‐rigid hybrid arm for the transrectal biopsy of the prostate is investigated 65 . The procedure consists of moving the ultrasound probe connected via a compliant soft part to the rigid robot arm near the prostate through the rectum and aligning it with identified lesions in the prostate.…”

Study on the Bending Characteristics of Soft Fingers with Four Grooving Methods

“…(4) Create the analysis step, adopt the statics analysis module, use the direct solution method to solve, and consider the large deformation of the material. (5) Set the general contact between the flexible finger surfaces, consider the friction, and set the friction coefficient to 0.3. ( 6) One end of the flexible finger is fixed, and the cable driving action can be simplified to the bending moment acting on the end of the cable [9] .…”

“…The remarkable flexibility of soft robots enables them to adapt to deformations in complex environments. These robots are currently widely utilized in aerospace and medical rehabilitation fields [3][4][5] . To achieve deeper advancements in the application of soft robots, continuous and in-depth research is essential.…”