Kamen Delchev

Design and performance study of an orthopaedic surgery robotized module for automatic bone drilling

Many orthopaedic operations involve drilling and tapping before the insertion of screws into a bone. This drilling is usually performed manually, thus introducing many problems. These include attaining a specific drilling accuracy, preventing blood vessels from breaking, and minimizing drill oscillations that would widen the hole. Bone overheating is the most important problem. To avoid such problems and reduce the subjective factor, automated drilling is recommended.

Robotized System for Automation of the Drilling in the Orthopedic Surgery. Control Algorithms and Experimental Results

Abstract Many orthopedic operations involve drilling and tapping before the insertion of screws into bone. Usually the drilling is executed by hand which brings lots of problems. The accuracy of the drilling, the possibility of braking the blood vessels after the rear hole, the oscillations widening the hole diameter – there are some of examples for that. But the bone overheating is the most important problem. To avoid these problems and reduce the subjective factor the automation drilling is recommended. In the work the automatic drilling module is presented as well as the experimental setup design for establishment the drilling process technical parameters and especially the bone resistant force measurement. The obtained results are shown and the corresponding conclusions are done.

Computer Simulation-Based Synthesis of Learning-Control Law of Robots #

Abstract The paper deals with computer simulation and synthesis of learning trajectory-tracking robot control based on the explicit form dynamic equations. Robots with inaccurate inertia parameters are considered. Two learning operators are proposed. The simplified one is a scalar function identical to the minimal eigenvalue of the inertial matrix of the dynamic equations. The complicated one is the inertial matrix itself. The learning operators are the basis of two learning-control laws, both with a feedback controller attached. For comparison of the results, a computer model of a virtual (test) robot with precise inertia parameters is assumed. The convergence of the learning procedure for both control laws proposed is examined by computer dynamics simulation of the resulting trajectory-tracking motion of the virtual robot. In spite of significant initial trajectory-tracking errors, good convergence of the learning procedures is achieved. The results are promising when the learning operator is in compliance with the robot inertial matrix.

Identification of Bone Structure During Automatic Drilling in Orthopedic Surgery

In orthopedic surgery the manipulation “bone drilling” is used very often and it is performed by hand drilling, which causes a lot of problems—getting the big outlets, breaking the tendons or blood vessels, protecting the rear bone wall (which brings one more cutting of the tissue), overheating, and so on. Automatic bone drilling could successfully solve these problems. The drilling orthopedic robot (DORO) is presented as a device for automatic bone drilling execution as well as its technical features and functional applications. The experimental results are shown for identification of the parameters of the drilling process, including the bone structure in part.

Eliminating of Far Pedicle Cortex Perforation by Automatic Spine Drilling

The need of the most precise manipulations in the orthopedic surgery concerns spine. The drilling takes place very often there. If spine cortices are broken by mistake then fatal problems appear as paralysis, block of breathing and death. Therefore in operation as pedicle drilling the far cortex perforation must be avoided. This paper shows that it can be done by bone drilling hand-hold robot ODRO. It is able to detect the bone far cortex and stops just before contact registration. Experimental results are presented. Also the results based on new algorithms and software are presented and discussed.

Far cortex automatic detection aimed for partial or full bone drilling by a robot system in orthopaedic surgery

ABSTRACT Far cortex detection during the bone-drilling process is a specific task in orthopaedic surgery. Any errors in its execution could damage the cortex wall from the inside, which often causes additional trauma even with a fatal result. Here we present some functionality enhancements of the drilling orthopaedic robot ODRO concerning the solution of the far cortex detection problem. The solution is based on software control of the thrust force applied to the bone during the drilling process. A new algorithm is created and its software realisation is provided. Experimental results are presented which verify and confirm the new functional characteristics of the robot. The risk of far cortex damage may be avoided by robot application and such precise operations may guarantee better success.

Design of a hand-held robotized module for bone drilling and cutting in orthopedic surgery

Bone drilling and cutting procedures are widely used in orthopedic surgery. Relatively high forces and temperatures experienced during bone drilling and cutting can cause significant damage to the bone as necrosis, widening of holes, breaking the tendons or blood vessels, which can make patient recovery long and painful. This paper presents a concept design of a hand-held robotized orthopedic system for bone drilling and cutting manipulations. The system consists of two executive modules for drilling and cutting, respectively. : bone drilling module detecting bone breakthrough is developed. It can monitor time, linear velocity, angular velocity, resistant force, depth of penetration and temperature during the drilling process. A design concept of a robotized oscillating saw for bone cutting is also presented. The saw is intended to perform cutting operations with preliminary setting of depth and stop automatically after the cutting process is completed. Cutting conditions will automatically change in accordance with bone density. Dynamical model using graph theory and the orthogonality principle is provided. CAD models of the prototype of the robotized bone cutting module are presented.

Automatic Bone Drilling in Orthopedic Surgery - Overcoming of the Drill Bit Bending at the Second Cortex

This paper discusses a problem appeared by drill bit bending during bone drilling in the orthopedic surgery, where precision is needed for screws to be implanted. The bone surface has a specific shape and the drill bit may slip a little along the bone before the process start, when a large thrust force is applied by hand-drilling. That could be seen and correct by the surgeon. But he can’t see inside – where the second cortex drilling starts. The drill bit bending leads to the worse screw fixation and even to the bone damage – if the drill bit stays off broken inside. To solve this problem an active force control is made by robot application. Experiments and results are presented.

Automatic Bone Drilling in Orthopedic Surgery Parameter Tuning of an Active Force Control

This paper deals with an active force control for automatic bone drilling. Orthopedic surgery often requires precise bone drilling for screws to be implanted. The hole quality in drilling process strongly depends on the applied thrust force (resistance force). In particular, a relatively large thrust force, applied in hand-drilling process, could cause a bone trauma (thermo necrosis or bone damage). To solve this problem we apply an active force control in order to achieve constant and safety drilling thrust force. Moreover, we propose an algorithm for parameter tuning of the considered control system.

Suppression of Deviations and Vibrations of Tethered Satellite

Abstract The present paper discusses the problems of planning and optimization of maneuver (reorientation) strategies of large-space flexible structures as long booms and tethered satellites subject to conditions for minimization of deviations and vibrations. An approach based on the multibody system methodology for dynamics simulation and forward analysis is proposed. The optimization problem is defined as nonlinear programming problem. Iterative procedure based on directional derivatives and consequential dynamic analysis is applied. Polynomial approximation of the input motion is used, its coefficient being changed using optimization techniques. The principle for minimization of the total energy of the deformable system is applied in an algorithm for planning of controlled motion and computation of driving forces of the actuators. Admissible velocities of the maneuvers are estimated. The process of exaggeration of high order vibrations is analyzed. Examples of maneuver implementation of extremely flexible tethered satellite and suppression of vibrations are presented.