George Boiadjiev

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.

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.

Application of the Servo-control Method with Standard Corrections for Robot-manipulators Control

This work presents a modified computed torque method application for a 7 d.o.f. robot control. Generally it could be applied to any other robotics system. The effectiveness and stability of the proposed controller have been discussed and the results from experiments presented. The proposed control method introduces additional corrections for the joints positions, velocities and accelerations and can compensate uncertainties due to the inexactness of the dynamics, describing the system or some parameter variation.

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.

Control System for Data Acquisition and Processing of Ankle-Foot Orthosis

Abstract The aim of this paper is to present an autonomous control system for active ankle-foot orthoses (AFO). An ankle-foot orthosis is commonly used to help persons with weakness of ankle dorsiflexor muscles due to peripheral or central nervous system disorders. The proposed orthosis has one degree of freedom which foot segment is connected to the shank segment by a rotational joint. In order to assure automatic adaptation of the joint torque the joint is fitted with direct drive actuator attached laterally and controlled by a microcontroller ATmega128. Realizing flexion/extension the actuator applies a torque adequate to the joint position of the human ankle during level ground walking. The control signals are received from two tactile sensor arrays incorporated in the foot part of AFO and in the insole of the healthy leg. During each gait cycle a microcontroller estimates the forward speed and modulates the swing phase flexion and extension in order to achieve quite normal walking dynamics. A feedback with Proportional-Integral-Derivative control (PID control) was used to estimate the trajectory of the foot and positioning the actuated foot segment of the AFO when the foot rotates about the ankle. A graphical presentation of the mathematical model and simulation of the dynamic system is done building a Matlab Simulink block diagram model. The proposed intelligent system is oriented to control different models of personalized ankle-foot orthoses designed using reverse engineering and rapid prototyping by the joint team Bulgarian Academy of Sciences/Cardiff University.

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.

Sensibility Control of Redundant Robots: Position Control by Image Trajectories

This work is dedicated to position control of redundant robots, realized with the help of the sensibility theory. The control method allows controlling the robot position following some working trajectory, and at the same time maintaining its orientation state unchanged or vice-versa. The latter is achieved by using the features of the four robot configuration space orthogonal fibrations. Their characteristics and role are clarified. A concept of robot image trajectories is formulated and its application is analyzed. The proposed method is going to be applied for a real-time control to a 7 d.o.f robot, based on Puma type construction. Simulations have been done for it, taking into account its dynamics and sensibility models and also by applying the position control method. The results and conclusions are presented.

Sensibility control of redundant robots: sensibility directions along trajectory tangent vectors

This work is dedicated to accuracy control of redundant robot-manipulators using sensibility approach. A manifold structure is applied to realize bases transition at local robot level. This assures optimal choice of drive subsets or combination of drives realizing motion with desired sensibility. The formulated condition satisfaction in the robot configurational space leads to precise trajectory tracing in the working zone (coincidence of the sensibility direction with the trajectory tangent vector). An illustrative example is presented and the explicit results are shown. The group theory application completes the considerations and it is helpful for better mechanical interpretation