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ARTHROBOT: A new surgical robot system for total hip arthroplasty


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This paper presents mechanisms and control methods of a new surgery robot for total hip arthroplasty (THA). To minimize the disadvantages of the conventional registration method, a new gauge-based registration method has been proposed, and a 3-DOF robot has been developed that can be mounted on a femur The proposed surgical robot can operate along a pre-programmed path autonomously, in addition to allowing a surgeon to directly control the motion of the surgical robot with their experience and judgment during an operation. For this purpose, a master is attached to the surgical robot and admittance display is used in control. ARTHROBOT this new arthroplastic surgical robot system, is expected to be adaptable to surgical needs and practice in the operating room
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ARTHROBOT : A New Surgical Robot System for Total Hip Arthroplasty
Dong-Soo Kwon*, Yong-San Yoon*, Jung-Ju Lee*, Seong-Young Ko*,Kwan-Hoe Huh*,
Jong-Ha Chung*, Young-Bae Park*, Chung-Hee Won**
* KAIST Mechanical Engineering Department (e-mail:
** Chungbuk University Hospital (e-mail:
This paper presents mechanisms and control methods
of a new surgery robot for total hip arthroplasty (THA). To
minimize the disadvantages of the conventional
registration method, a new gauge-based registration
method has been proposed, and a 3-DOF robot has been
developed that can be mounted on a femur. The proposed
surgical robot can operate along a pre-programmed path
autonomously, in addition to allowing a surgeon to
directly control the motion of the surgical robot with their
experience and judgment during an operation. For this
purpose, a master is attached to the surgical robot and
admittance display is used in control. ARTHROBOT, this
new arthroplastic surgical robot system, is expected to be
adaptable to surgical needs and practice in the operating
1. Introduction
Either by trauma or disease, a hip joint can be damaged,
and this induces pain and reduces the range-of-motion in
the hip joint. In this case, Total Hip Arthroplasty (THA),
which is the name of an operation for replacing the
damaged hip joint with an artificial hip-joint, is performed.
The artifical hip joint is composed of an acetabular
component and a femoral stem, the stem being either one
of two types, cemented or cementless. As its name
suggests, a cementless stem does not need cement because
the bone grows into the porous part on the stem and the
stem is fixed to the femur. When using a cementless stem,
the conformity between the bone and the implant greatly
affects the success of the surgery and the recovery of the
patient [1]. Thus it is very important to carve a hole in the
femur that precisely fits the shape of the artificial hip
implant in order to increase conformity and minimize gaps.
In a conventional cementless THA, the surface
conformity between the bone and the implant is less than
30%. This causes slow recovery and shortens the life of
the implant [2]. To improve this situation, robotic surgical
systems that can make a precise cavity in the femur were
developed [3]. In particular, Integrated Surgical System
Co. developed a commercial THA system, the
ROBODOC® Surgical Assistant System [4].
By using these surgical robots, the surface conformity
can be improved and patients can recover more rapidly [5].
In such robotic systems, to register the surgical robot to
the femur, the fiducial markers are implanted onto the
femur of a patient before surgery, and a CT scan of the
femur is performed. In real surgery, the robot system is
registered through comparing the measured positions of
the markers and the positions of the markers in CT scans.
This paper introduces a new arthroplastic surgical
robot system which we call ARTHROBOT. Since a small
surgical robot is mounted onto the patient’s femur by a
bone clamp, the registration procedure becomes simple,
and the cost of the operation can be reduced. Since the
robot has a master/slave-combined structure, a surgeon
can directly control the motion of the surgical robot like
an advanced surgical tool. Through an admittance display,
the surgeon can feel the comfortably pre-defined virtual
environment. Also a virtual hard wall is displayed at the
surgical boundary to ensure surgical accuracy.
2. Gauge-based Registration Method
We have proposed a greatly simplified cavity
machining method for robot-assisted total hip athroplasty
surgery that requires neither CT scanning nor the insertion
of fiducial markers before surgery [6].
In this technique, a surgeon prepares the distal portion
of the femoral cavity using a conventional manual
reaming process which centers the distal end of the cavity
relative to the cortical bone. Next, the surgeon inserts a
reamer-shaped registration gauge into the prepared distal
cavity aligning the front of the gauge with the direction of
the femoral neck; this defines the orientation for the final
implant (Fig. 1).
The surgeon then attaches the base for a small surgical
robot to the gauge part of an external femoral clamp using
an adjustable linkage consisting of two sets of ball and
socket joints and a slider. Both the base frame and the
registration gauge have matching mating surfaces so that,
with the linkage unlocked, the surgeon can maneuver the
base frame into solid contact with the registration gauge
(Fig. 2).
Proceedings of the 2001 IEEE/RSJ
International Conference on Intelligent Robots and Systems
Maui, Hawaii, USA, Oct. 29 - Nov. 03, 2001
0-7803-6612-3/01/$10.00 2001 IEEE 1123
Fig. 1. Proposed hip arthroplasty methods
Fig. 2. Alignment of gauge and base frame
(a) A frame on the sawbone (b) A clamp on the femur
Fig. 3. The frame attached on the femur
Once the linkage is locked, the base frame is fixed
relative to the femur and the registration gauge can be
removed. At this point, the robot can be mounted on the
base frame to machine the femoral hole (Fig 3(a)). It was
verified in the operating room that a bone clamp used in
the frame could be attached to the femur and that there
was enough space for the robot to be mounted (Fig 3(b)).
3. A Surgical Robot Design
In order to perform the proposed surgical method, a
small surgical robot needs to be mounted on the femur.
The minimum degree-of-freedom (DOF) of the robot is
three for most stem shapes of artificial hip joints. This
section presents the mechanism of a surgical robot and its
optimal design.
3.1 The mechanism of the surgical robot
Considering the dexterity of the THA, five kinds of
candidates for the mechanism of the surgical robot are
chosen as shown in Fig. 4.
Fig. 4. Candidates for the surgical robot
Since the robot must be attached onto the patient’s
femur to perform a proposed operation, not only precision
and rigidity, but also weight and size are important. For
decision criteria, the following factors of precision,
rigidity, weight, size, number of joint, disinfection, and
workspace are chosen. Five kinds of candidates are rated
on three levels about each criterion, and these grades are
multiplied by proper weighting factors. Each candidate is
evaluated by the sum of the weighted grades. From these
evaluations, the parallel-3RPS type (Fig. 4 (e)) is selected
as the suitable mechanism for the surgical robot.
3.2. Performance index
A performance index has been formulated to optimize
dexterity, force requirement, and uniformity. To represent
a global dexterity index D
, a global external force index
, and the gradient value of these (GD
, GF
), the overall
performance index is defined as Eq.(1).[7][8]
(a) Femur is exposed.
(b) Femoral head is removed, and frame is attached to femur, the
hole is made using a starter.
(c) A reamer-shaped gauge is inserted into femur
(d) Frame is maneuvered into place against reamer-shaped gauge
and locked into position
(e) Gauge is removed and robot installed on frame to machine
cavity in femur
Here, the bar symbol indicates a normalized value of
each index value.
3.3. Optimization
The surgical robot is optimized over the possible range
of all design variables. The workspace of initial/optimized
design and the performance indices are shown in Fig. 5
and Table 1. The workspace of optimized design is more
similar to the required workspace than that of the initial
design. The precision at the tool tip is much improved by
the concentrated workspace. The maximum force index
shows a triple value compared to the initial design after
optimization. This makes it possible to use a smaller
actuator, so the total weight and size of the robot can be
decreased. Moreover, the overall performance index PI is
doubled. The optimized prototype is shown in Fig. 6 (a)
and a real surgical robot is manufactured as shown in Fig.
6 (b) based upon this optimization result.
(a) Initial design (b) Optimized design
Fig. 5. Comparison of workspace
a global
index D
a global
index F
a gradient
index GD
a gradient
index GF
index PI
0.929 0.248 4.26 0.18 1.71
0.964 0.705 3.46 0.174 3.43
Table 1. Comparison of performance index
(a) An optimized prototype (b) A manufactured robot
Fig. 6. The parallel-type surgical robot
4. Control of a Master/Slave-Combined
Surgical Robot
Most previous robots used in THA grind the bone
along a pre-programmed path. In surgery, the surgeon’s
experience and judgment are very important factors
affecting the success of its outcome. By combining a
master and a slave robot, a surgeon can control the motion
of the surgical robot directly, thus allowing the surgeon to
exercise his or her discretion during surgery, in addition,
the robot also retains the capability to operate
autonomously along a pre-programed path.
In the master/slave-combined surgical robot, the force
exerted by a surgeon to the master is used as command
signals for desired motion. For easy operation of a
surgical robot in variable environmental characteristics,
the admittance between human guide forces and surgical
robot velocity must be shaped properly. And the virtual
hard wall display has been adopted to make a surgeon feel
the cavity boundary.
4.1. 1-DOF system modeling
The characteristics of a master/slave-combined surgical
robot can be modeled as a 1-DOF mass, damper linear
system as shown in Fig. 7.
Fig. 7. 1-DOF master/slave-combined robot system
In Fig. 7, f
and f
denote an interaction force between
human arm and robot, and between robot and environment,
respectively. The dynamics of a human arm, a robot and
an environment are given by the following equations:
xkxbxmf ++=
xkxbxmf ++=
denote muscle force of the human arm
and force/torque of environment, respectively.
and k
denote mass, damping coefficient, and stiffness of
the human arm, while
, b
and m
denote those of
the robot and environment.
4.2. Admittance display
In order to carve a hole in the femur, it is desired that
the master/slave-combined surgical robot has high
stiffness, and low friction. In this kind of a robot system,
measured interaction forces or torques are used as the
inputs to calculate the desired trajectory. This control
scheme is generally called admittance display mode [9].
In this study, the controller is constructed to maintain
desired admittance between human guide force at the
master and the robot velocity. Measured force
is used as
input for admittance model Y
(s) to generate a trajectory
of the surgical robot based on desired admittance. The
master/slave-combined surgical robot is position-
controlled. If the position controller perfectly follows the
trajectory based on desired admittance, it is possible to
have easy maneuvering of the surgical robot regardless of
environmental conditions.
Local position-controller of the surgical robot is as
The trajectory generation based on desired admittance
is as follows:
, b
and k
denote mass, damping coefficient,
and stiffness of desired admittance model. From equations
(5)~(8), the controller of the master/slave-combined
surgical robot is constructed as shown in Fig. 8,
Fig. 8. Controller for admittance display
where H and E denote impedance of human arm and
environment. G
is the robot system.
4.3. Virtual hard wall display
Since the geometrical information of the artificial
implant is known, the surgical region can be divided as
shown in Fig. 9. In previous research, a virtual hard wall
is displayed using a virtual wall model composed of a
spring and damper [10,11]. However, we have adopted a
new strategy for the master/slave-combined surgical robot
having high stiffness and friction to ensure surgical
Fig. 9. Surgical region division
In Region I, far from the boundary, relatively high
admittance is displayed for easiness of operation. And in
Region II, near the boundary, relatively low admittance is
displayed and the surgeon feels difficulty in maneuvering
the surgical robot. This leads to low robot velocity with
respect to guide force and increases safety. This also gives
the surgeon a feeling of being near the boundary of the
surgical region. Near the surgical boundary that is defined
based on the 3-D CAD model of a femoral stem, the
desired position of surgical robot is generated so as not to
go over the boundary. This makes it impossible for the
robot to exceed the surgical boundary regardless of the
guide force of a surgeon within the actuator capacity.
5. Experiments
Before applying the control method to the proposed
parallel-type surgical robot, to evaluate the machining
performance of a manufactured surgical robot, we carry
out an experiment carving a hole using a parallel-type
surgical robot. The robot is controlled autonomously
along a pre-programmed tool-path by the PID position
controller. The tool-path is generated based on the 3-D
CAD model of a femoral stem. Because the robot is fixed
by the bone clamp in real surgery, the experiment should
be carried out with actual frame to know the accuracy of
the whole system. However, at first, since we want to
know just the accuracy of the robot alone, the experiment
is performed using the jig in Fig.10. Wood is chosen as the
machining material, because its material property lies
between that of cortical and cancellous bone.
After the machining process, the specimen is cut into
halves using a milling machine. Then the surface of
processed specimen is measured by a Coordinate
Measuring Machine (DUKIN Co., ASTRO 543C).
Measuring points are distributed at 2mm intervals. 35~51
valid data points are acquired from each specimen and the
results are compared with the CAD model. The relative
error has been calculated without considering the offset
(Fig. 11).
Fig. 10. Parallel-type surgical robot and experimental set
It can be known that most of the errors are in the range
of ±0.2mm. This is a much improved result compared
with that of manually operated surgery, and below the
allowable error of total hip replacement surgery[13].
Therefore, it is expected that this surgical robot can be
used in real hip surgery.
Fig. 11. Machining error
After the experiment on the machining performance,
we apply the control method to the master/slave-combined
surgical robot. In the experiment, the surgical region is
simplified as a concentric circle. To easily evaluate the
control method, we control the robot in only 2DOF
motion. The cutting materials are polyethylene,
MDF(Medium Density Fiber) board and the femur of a
cow. The Youngs modulus of polyethylene is 1.1GPa ,
and that of MDF is 0.3 Gpa. The spongy bone of a human
is 0.1 ~ 1.0GPa [12], so these materials are suitable to
simulate human spongy bone characteristics.
The first experiment is to view how the operator feels
different force and velocity w.r.t. an admittance model. In
Region I,
= 0.2 [Nsec/mm] and its radius is 13mm. In
Region II,
= 0.8 [Nsec/mm], k
= 0.05 [N/mm], and its
radius is 20mm. When an operator pushes the handle of
the master/slave-combined manipulator in the y-direction,
position and forces are measured as shown in Fig. 12. In
this case, the operator has high-speed motion and
relatively low force for maneuvering in Region I. The
operating force is about 1.0N in Region I, and 2.5N in
Region II. Desired admittance of Region I is
= 1/b
5.0 and real admittance in Region I is about 4.983, which
close to the desired admittance value. This result shows
that admittance of human force to robot velocity can be
shaped to desired value, and the operator can feel the
master/slave-combined system as desired admittance.
2 3 4 5 6 7 8 9 10 11
y (mm)
2 3 4 5 6 7 8 9 10 11
time (sec)
Fy(N) [solid]
region [dash]
Fig. 12. Admittance display with different model
The second experiment shows the performance of the
virtual hard wall display. In this experiment we compare
the cutting result of MDF by autonomous position control
and master/slave-combined control with virtual hard wall
display. The cutting profile is simplified as a half circle.
The radius of the boundary is 20mm and cutting speed is
about 6mm/sec.
10 12 14 16 18 20 22 24 26 28
time (sec)
error (mm)
10 12 14 16 18 20 22 24 26 28
time (sec)
error (mm)
(a) Autonomous control (b) Virtual hard wall display
Fig. 13. Positional error at the surgical boundary
Fig. 13 shows the positional error at the surgical
boundary. The gap between the artificial hip implant and
the bone should be less than 0.3 to 0.5mm[13]. So the
surgical robot needs to have a position accuracy to less
than 0.3mm. By the autonomous control (12(a)), position
error is less than about 0.223 mm. In Fig. 12 (b) by the
virtual hard wall display, the maximum position error at
the surgical boundary is 0.240 mm. From this result, it is
shown that the performance of the virtual hard wall
display is acceptable.
The third experiment shows how the master/slave-
combined manipulator cut an arbitrary profile by the
operator. The femoral bone of a cow is used and the
surgical boundary is defined as a circle with a 15mm
radius. Here, the admittance model of Region I is
= 0.4
[Nsec/mm] and the radius of Region I is 12mm. In Region
II, the admittance model is
= 1.0 [Nsec/mm] and k
0.05 [N/mm].
First, the operator cut around the surgical boundary and
then cut arbitrary spiral profile inside the surgical
boundary as shown in Fig 14. The cutting profile is made
well by the operator using the master/slave-combined
manipulator. In each surgical region, the operator feels a
different force and velocity relationship by a different
admittance model. In Region I, the human guide force is
relatively low and the cutting speed is high with respect to
Region II. At the surgical boundary, human guide force is
larger than that of other regions and the operator can feel
the surgical boundary and the position accuracy is
satisfied by the virtual hard wall display.
Fig. 14. Cutting profile
6. Conclusion
This paper presents an on-going development of a
surgery robot for total hip arthroplasty that includes a new
registration method and a control method. The proposed
gauge-based registration method simplifies the
registration procedure, and the parallel-type surgical robot
is mounted on the bone clamp, which is attached to the
femur. The surgical robot can be controlled along a pre-
programmed path; in addition, it can be directly controlled
by a surgeon with the master/slave-combined structure.
Preliminary experiments show that the proposed surgical
robot can be operated with an acceptable degree of
positional error.
Through experiment, it has been shown that a operator
can carve the femur of a cow into a desired profile,
changing the moving direction and velocity of the
proposed parallel-type surgical robot. Position accuracy at
the surgical boundary by a virtual hard wall display has
been shown to be acceptable.
Currently, plans are being made to design a more
compact second prototype for clinical test.
This work has been supported by the Human-friendly
Welfare Robot System Engineering Research Center
(HWRS-ERC), KAIST in Korea.
[1] Piston R, Engh C, “Osteonecrosis of the femoral head
treated with total hip arthroplasty without cement”,
bone Joint Surg AM
, 1994, 76A(2): 202~214
[2] Lee E H, Yoon Y S, Park Y B., “Study of surgical
robot registration method using block gauge”,
Proceedings of the first International Workshop on
Human-friendly Welfare Robotic Systems, KAIST, 2000
[3] J. Pransky, “Surgeons’ realizations of ROBODOC”,
Industrial Robot Vol.25 No.2 1998, pp105-108
[5] Meister, D.; Pokrandt, P., Both, A.,”Milling accuracy
in robot assisted orthopaedic surgery”,
Proceedings of
the 24th Annual Conference of the IEEE, Volume: 4 ,
1998 , 2502 –2505
[6] Yoon YS, Lee JJ, Kwon DS, Won CH, Hodgson AJ
and Oxland T, “Accurate Femoral Canal Shaping in
Total Hip Arthroplasty Using a Mini-Robot”,
Proc. Of
IEEE Int. Conf. on R&A, 2001, Volume 4,3214-3219
[7] Lee S H. Yi B J. Kwak Y K, “Optimal kinematic
design of an anthropomorphic robot module with
redundant actuators”,
Mechatronics, 1997, 7(5):
[8] Dong-Soo Kwon, Ki Young Woo and Hyung Suck Cho,
“Haptic Control of the Master Hand Controller for a
Microsurgical Telerobot System”,
Proc. Of the 1999
IEEE Int. Conf. On Robotics and Automation
, Detroit,
Michigan, 1999, May, pp.1722~1727
[9] C.L. Clover, “A Control-System Architecture for Robots
Used to Simulate Dynamic Force and Moment Interaction
Between Humans and Virtual Objects”,
IEEE Trans. On
Systems and Cybernetics,Vol.29, No. 4, November 1999
[10] J.E. Colgate, “Implementation of stiff virtual walls in
force-reflecting interfaces”,
IEEE Virtual Reality Annual
International Symposium, 1993
[11] S.C. Ho, R.D. Hibberd, B.L. Davies, “ Robot Assisted
Knee Surgery”,
IEEE Engineering in Medicine and Biology,
[12] Joseph D. Bronzino, “ The Biomedical Engineering
HANDBOOK”, CRC PRESS, pp. 706, 1995
[13] L. Carlsson, T. Rostlund, B. Albrektsson and T.
Albrektsson, “Implant Fixation Improved by Close Fit.
Cylindrical Implant- Bone Interface Studied in Rabbits”,
Acta Ortho. Scand., Vol. 59, 272-275, 1988
... Дальнейшее развитие роботизированных систем было проведено в исследовательском институте SRI International и Intuitive Surgical с внедрением хирургической системы da Vinci Surgical System и компьютерного движения с роботизированной хирургической системой AESOP и ZEUS [17]. Эволюция роботических систем кратко представлена на рисунке 2 [18][19][20][21][22][23][24][25][26][27][28]. ...
... e c u r o . r u 46 Рис. 2. Эволюция роботических систем [18][19][20][21][22][23][24][25][26][27] Fig. 2. Evolution of surgical robots [18][19][20][21][22][23][24][25][26][27] дика, которая позволила сохранить уретру, матку, влагалище и оба яичника. Мочевой пузырь был заключен в эндоскопический мешок и удален через небольшой субумбиликальный разрез. ...
... e c u r o . r u 46 Рис. 2. Эволюция роботических систем [18][19][20][21][22][23][24][25][26][27] Fig. 2. Evolution of surgical robots [18][19][20][21][22][23][24][25][26][27] дика, которая позволила сохранить уретру, матку, влагалище и оба яичника. Мочевой пузырь был заключен в эндоскопический мешок и удален через небольшой субумбиликальный разрез. ...
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A l’heure actuelle, les robots sociaux representent une innovation sociale dans le secteur de l’intervention aupres des personnes presentant une deficience intellectuelle (DI) ou un trouble du spectre de l’autisme (TSA). Toutefois, pour assurer leur deploiement optimal en intervention, il convient de realiser une analyse de certaines dimensions. L'article realise cette analyse en s'appuyant sur le MAP2S. Au niveau clinique des impacts positifs sont observes sur plusieurs dimensions. Au niveau technologique, des caracteristiques a considerer lors du choix du robot sont identifiees. Au niveau de la gestion, les couts et la compatibilite technique constituent des elements consideres. En somme, la recherche devra poursuivre les travaux dans le domaine et aussi documenter les enjeux associes a l'utilisation de tels outils d'intervention.
The aim of this work, which was part of a research programme to develop a minimally invasive multirobotic neurosurgery system for cerebral tumour ablation, was the design and modelling of a robot that can be deployed inside the brain, along curved trajectories, with no free space surrounding its structure nor any natural guide to help its progression. After definition of the deployment task, a state of the art search found a wide range of systems, from which a bio-inspired continuum design based on the elephant's trunk was selected. The modular robot approach was defined and geometrically modelled by combining a cinematic chain with the continuum mobility of the robot. A deployment strategy, based on an ordered succession of local extensions/retractions for an iterative elongation of the robot, was formalised for the generic case of N modules, then validated with plans of simulations of robots composed of 1 to 3 modules (trajectory following error less than 1 mm). The agar gel (whose texture is close to that of the brain) study model was used to estimate the penetration efforts of the robot in the brain, and CAD to construct a demonstrator robot on springs. A human/machine interface was programmed to simulate and control the robot, and tests were conducted to validate certain aspects of the deployment. A second, pneumatically actuated, demonstrator will be constructed to carry out a comparative study of the two prototypes. While there is room for improvement in some areas, the preliminary results are encouraging. Collaborative works with specialists from different fields should make it possible to optimize the deployment robot.
The history of medical robotics is recent with the first experiments in the field of neurosurgery dating from the 1980s. Important factors relating to its progress have been the rapid evolution of medical imaging technology, as well as in the medical world a growing interest in robotics, which is today a major and practical form of improving medical practice. The recent developments in medical robotics in the last few years have coincided with the arrival of small robots, which are more economical, concentrating on precise indications, in contact with the patient in a way that frees us from the problem of compensating for physiological movement. medical image processing; medical robotics
Robotic–assisted surgery is a new trend in medicine. To overcome problems in artificial cervical disc replacement surgery, a robot-assisted surgery system which consists of an active 6-UPS parallel robot and its control system, a surgical planning system and an optical tracking system was developed to replace the cumbersome mechanical positioning device. A positioning method for robot-assisted cervical disc replacement surgery will be studied. Firstly, the robot-assisted surgery system is described. Secondly, the coordinate transformation method for robot-assisted surgery positioning is given. Then, a preoperative position and pose planning method is given. Finally, a robot-assisted surgery positioning by using the method in this paper is carried out. The result shows that the robot-assisted surgery positioning method in this paper is an effective method for artificial cervical disc replacement surgery.
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In this paper, a study on the optimal dynamic design for an anthropomorphic robot module with redundant actuators is performed. Musculoskeletal structure of human body is a typical example of redundantly actuated mechanism, and provides superior features than general robotic mechanisms. An anthropomorphic robot module that resembles the structure of human upper limb is introduced to utilize the advantages of redundant actuation system. Optimal dynamic design of the proposed robot module that follows optimal kinematic design is carried out to maximize the advantages. Five design indices are introduced, which are associated with inertia matrix, inertia power array representing nonlinear terms and gravity terms of the dynamic modeling equation. A concept of composite design index based on max-min principle of fuzzy theory is employed to deal with multi-criteria based design. As a result of dynamic optimization, a set of dynamic parameters, representing optimal mass distribution of the manipulator is obtaind. It is shown that the dynamic optimization yields a notable enhancement in dynamic performances, as compared to the case of kinematic optimization only.
Conference Paper
The performance of a haptic interface is often reported in terms of the dynamic range of impedances it may represent. At the low end, the range is typically limited by inherent dynamics of the interface device, such as inertia and friction. At the high end, the range is typically limited by system stability. In a number of the applications, the principal limitation has proven to be the achievable upper limit on impedance. Therefore, a benchmark problem of considerable importance is the implementation of a stiff "wall". Contacting a wall may be described as the reversible transition from a region of very low impedance to one of very high impedance. A theoretical analysis (supplemented with discussion of experimental and simulation results) of stiff wall implementation is presented. The main result is a criterion for the passivity of a virtual wall in terms of two nondimensional parameters
Motivated by the redundant actuation mode of the human body, which produces several unique functions that general robotic mechanisms cannot generate, an anthropomorphic robot module resembling the musculoskeletal structure of the human upper limb is investigated. Specifically, optimal kinematic design of the proposed robot module is treated. Initially, the kinematic model of the robot module is obtained, and five design indices are then defined based on the kinematic model. These indices include workspace area, Jacobian isotropic index, maximum force transmission ratio, and gradient design indices for the Jacobian isotropic index and the maximum force transmission ratio. To deal with this multi-criteria based design, a kinematic composite design index (KCDI) is introduced which combines several individual design indices as a unique design index using the max-min principle of fuzzy theory. Two KCDIs are considered as objective functions in the kinematic optimization. One includes the three design indices without the two gradient design indices, and the other includes all five design indices. As a result of optimization based on the two KCDIs, two sets of nine optimal kinematic design parameters are obtained. The two designs are compared with respect to three operational performances: maximum load handling capacity, maximum hand velocity and maximum hand acceleration capability. Optimal actuator sizes of the two designs are also compared for the given specifications of three operational performances. The design taking into account all five design indices shows superior operational performances and smaller actuator sizes than those of the design ignoring gradient design indices.
Describes interviews with the two surgeons that have performed the most surgeries worldwide using the RoboDoc system, an integrated system that combines computer-based medical imaging and surgical robotics systems. For both doctors, the RobDoc system has exceeded their initial expectations. The article also describes the benefits of the RobDoc system as compared to the manual method of cementless implantation.
Conference Paper
We propose a greatly simplified femoral canal shaping method for robot-assisted total hip replacement surgery that requires neither CT/MRI imaging nor insertion of fiducial markers before surgery. A reamer-shaped registration gauge is inserted into the femoral canal and used to position a base for a robot that is mounted on the top of the femur and used to prepare the femoral canal. In a study using 5 fresh cadavers, the average registration error for selected points near the surface of the femoral cavity was 0.59 mm; this is comparable to the errors reported for the geometry-based registration methods.
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Cylindric titanium implants of three different diameters were inserted and stabilized in a 3.7-mm burr hole in the rabbit tibia. the purpose of the study was to investigate the interfacial reaction to screw- and cylinder-shaped implants, and to determine if there is a critical gap at the insertion between bone and implant that prevents direct cortical bone apposition on the implant. the study indicated that this critical gap approached zero. © 1988 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.
With use of porous-coated implants, total hip arthroplasty was performed in a consecutive series of thirty patients (thirty-five hips) who had a preoperative diagnosis of late-stage (Ficat and Arlet stage-III or IV) osteonecrosis of the femoral head. The patients were evaluated clinically and radiographically, and the data were recorded in a prospective manner. The average duration of follow-up was seven and one-half years (range, five to ten years). The average age of the patients at the time of the operation was thirty-two years (range, twenty-one to forty years). Signs of osseointegration of the femoral stem to the host bone were demonstrated in thirty-three hips (94 per cent). In the porous-coated hemispherical acetabular cups of these hips, an optimum bone-implant interface was identified and maintained, suggesting bone ingrowth. The rate of revision was 3 per cent (one hip) for the femoral side and 6 per cent (two hips) for the acetabular side, for an over-all rate of 6 per cent. All patients maintained a high level of activity postoperatively. There was moderate or severe remodeling of proximal femoral resorptive bone and stress-shielding in six hips (17 per cent) and osteolytic reactions in six hips. Complications were frequent (six hips) and included one deep infection; two dislocations; two instances of heterotopic ossification; and one fracture of the calcar femorale, which occurred intraoperatively. The thirty patients had a lower rate of revision and improved clinical outcomes compared with other reported series of young patients managed with total hip arthroplasty with cement who had the same diagnosis and similar postoperative follow-up. However, the latter series involved implants of an earlier design that had been inserted with older techniques of cementing. When arthroplasty is considered for the treatment of late-stage osteonecrosis of the femoral head in young patients, the use of total hip implants without cement that allow for bone ingrowth appears to be a viable alternative to arthroplasty with use of cement. However, longer follow-up is needed to determine the outcome of the osteolytic reactions that we observed. We therefore recommend this procedure with some caution because of the high rate of complications and the potential for failure of the arthroplasty related to the osteolytic reactions.
Conference Paper
A microsurgical telerobot system has been developed based on the results of the operation task analysis. The telerobot system is composed of a 6-DOF parallel micromanipulator attached to the macro-motion industrial robot and a 6-DOF force-reflecting haptic master device. The master device uses five-bar parallel mechanisms driven by harmonic DC servomotors. The proposed 6-DOF master hand controller has nonlinear coupled dynamics and friction. Since the disturbance force due to friction, gravity and coupled inertia can distort the operator's perception, a disturbance observer is introduced in the operational space and implemented in the microsurgery master hand controller
Conference Paper
Experiments with industrial robot systems showed that the accuracy of these systems is not sufficient for many surgical applications. Hence, we developed an algorithm which takes the trajectory generator of the robot control system into account. Furthermore, the inhomogeneous milling characteristics of a bone are predicted by its computed tomography (CT). Results from experiments demonstrated that the demanded accuracy can be achieved using this approach. Since December 1997 several patients have been treated with our surgical robot CASPAR, which encapsulates this strategy in the field of total hip replacement (THR)