Caveats on the first-generation da Vinci Research Kit latent technical constraints and essential calibrations Zejian Cui12 Joao Cartucho1 Stamatia Giannarou1 and Ferdinando Rodriguez y Baena12

2025-04-30 0 0 1.89MB 15 页 10玖币
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Caveats on the first-generation da Vinci Research Kit: latent technical
constraints and essential calibrations
Zejian Cui,1,2, Jo˜
ao Cartucho,1, Stamatia Giannarou1, and Ferdinando Rodriguez y Baena1,2
Abstract Telesurgical robotic systems provide a well estab-
lished form of assistance in the operating theater, with evidence
of growing uptake in recent years. Until now, the da Vinci
surgical system (Intuitive Surgical Inc, Sunnyvale, California)
has been the most widely adopted robot of this kind, with more
than 6,700 systems in current clinical use worldwide [1]. To
accelerate research on robotic-assisted surgery, the retired first-
generation da Vinci robots have been redeployed for research
use as “da Vinci Research Kits” (dVRKs), which have been
distributed to research institutions around the world to support
both training and research in the sector. In the past ten years,
a great amount of research on the dVRK has been carried out
across a vast range of research topics. During this extensive
and distributed process, common technical issues have been
identified that are buried deep within the dVRK research and
development architecture, and were found to be common among
dVRK user feedback, regardless of the breadth and disparity of
research directions identified. This paper gathers and analyzes
the most significant of these, with a focus on the technical
constraints of the first-generation dVRK, which both existing
and prospective users should be aware of before embarking
onto dVRK-related research. The hope is that this review will
aid users in identifying and addressing common limitations of
the systems promptly, thus helping to accelerate progress in the
field.
I. INTRODUCTION
Robotic-Assisted Minimally Invasive Surgery (RMIS) has
gained significant popularity in recent years due to its
advantage of causing less tissue trauma and reducing hospi-
talization time for patients. Of all surgical robotic platforms
available in the market, the da Vinci robot (Intuitive Surgical
Inc, Sunnyvale, California) has dominated RMIS, with more
than 10M operations having been performed on this platform
in the past twenty years [2]. To further propel RMIS research
on the da Vinci surgical platform, in 2012, an initiative was
launched to repurpose retired first-generation da Vinci robots
by converting them into da Vinci Research Kits (dVRKs)
[3], which consist of both a software package and hardware
controllers. These dVRKs have been distributed to research
institutions around the world. Until now, more than 40
research groups across 10 countries have benefited from
the initiative, forming a thriving dVRK research community,
with more than 250 peer-reviewed research papers on the
dVRK having been published.
These authors contributed equally to the work.
Zejian Cui: zejian.cui19@imperial.ac.uk
Jo˜
ao Cartucho: j.cartucho19@imperial.ac.uk
1The Hamlyn Centre for Robotic Surgery, Imperial College London,
London SW7 2AZ, UK
2Mechatronics in Medicine Lab, Department of Mechanical Engineering,
Imperial College London, London SW7 2AZ, UK
Fig. 1. The first-generation dVRK with two surgeon-side manipulators
(SSMs), three patient-side manipulators (PSMs) and one endoscopic camera
manipulator (ECM)
Although research conducted on the dVRK branches into
different topics, almost all of these works deal with data
directly provided by the dVRK, containing kinematics, image
and system information, as described in [2]. These data are
arguably the best source of information available to users
who wish to keep abreast of the latest state of the robot as
they develop novel research on the dVRK. However, blind
reliance on the fidelity of these data can be risky. The inac-
curacy of dVRK data partly arises from the intrinsic design
of the telesurgical platform, and partly from limitations of
the factory calibration of the hardware, which has only been
improved upon in recent years thanks to a growing interest in
the field and the many contributions of researchers working
with the dVRK. Awareness of these seminal works should be
heightened within the dVRK community, while thus far, there
only exists one review paper about the dVRK [2], which
focuses on categorizing research in terms of relevant high-
level application areas.
To fill in this gap, in this paper we aim to analyze the
technical constraints identified within the first-generation
dVRK so that users can be aware of these shortcomings
and take corrective actions to overcome these, in pursuit of
better research outcomes. We have based this review paper
on existing literature and the feedback from researchers of
the dVRK community, as detailed in Sec. II.
According to our initial research, there is a general con-
sensus among dVRK users about the inaccuracies within the
dVRK kinematics and image data, which necessitates studies
on essential kinematics and camera calibration. Allowing for
arXiv:2210.13598v2 [cs.RO] 12 Jul 2023
the fact that hand-eye calibration is an indispensable part of
teleoperation, the accuracy of which can have a profound
impact on subsequent task implementations, we also stress
technical concerns about hand-eye calibration. Additionally,
we address potentiometer calibration after weighing up its
substantial impact on the performance of autonomous task
execution, even though, thus far, to the best of our knowl-
edge, there is no literature about this topic. In the follow-
ing sections, kinematics calibration, hand-eye calibration,
potentiometer calibration and camera calibration problems
are detailed in Sec.III, VI, IV and V, respectively. For each
of these, we first identify the nature of the problem, then
distill prevailing schools of thought concerned on how to
tackle them, and finally we point out potential paths for better
addressing these problems, placed in the dVRK framework.
A discussion is presented in Sec.VII, where we summarize
the main findings, and other miscellaneous dVRK technical
issues uncovered during the survey.
II. SEARCH METHODOLOGY
A. Literature review
To identify the most significant technical constraints that
have hampered research progress with the dVRK, we first
looked into all papers on the dVRK across different re-
search application areas and gathered common issues that
researchers claimed to have affected task performance, taking
advantage of the latest review paper on the subject, which
encompasses papers on the dVRK from year 2014 to 2021
[2]. We also employed the keywords “dVRK” paired with
“error”, “calibration” and “task performance” individually on
Google Scholar, ScienceDirect and RefWorks and included
all relevant findings in this survey.
B. Consultation with researchers
1) Leading researchers: Having gathered a list of tech-
nical issues reported by dVRK users in the literature, we
consulted with leading researchers of the dVRK community
(Mr. Anton Deguet and Dr. Simon DiMaio) about whether
these issues have been discovered under the first-generation
dVRK and thus can be regarded as universal.
2) Peer researchers: We designed a questionnaire fea-
turing selected technical issues, which we deemed to be
“universal”, and had it distributed within the dVRK com-
munity1. The design of the questionnaire and a summary of
user responses are detailed in Appendix I.
III. KINEMATICS CALIBRATION
A well-acknowledged technical issue within the dVRK
is its time-variant inaccurate forward kinematics, which
induces a poor surgical tool tip pose estimation, reflected
by a discrepancy in readings of up to 1.02mm [4], [5]
between the alleged tip pose streamed from the dVRK
and the ground truth observed by an external means. This
discrepancy, termed positioning error in this paper, has
exceeded the sub-millimetre positioning accuracy required by
1More info at: https://jhudvrk.slack.com
RMIS [6], having repercussions on diverse research projects
implemented on the dVRK. Note that kinematics errors
exist in all individual joints of the dVRK; however, it is
in the end effector position that the discrepancy caused
by the kinematics errors is most evident, because of the
accumulation of errors across all the joints.
A. Need for kinematics calibration
For research on surgical subtask automation, accurate
positioning is required, such as in debridement [7], suturing
[8], [9], needle extraction [10], and peg transfer [11]–[13],
where a surgical instrument is required to move to the target
grasping point. For research on the development of Active
Constraints (AC, also known as virtual fixtures) via the
dVRK, positioning accuracy will affect the proximity query
result, and therefore the entire enforcement stage of the AC
implementation [14]–[17]. Even for research on image-based
hand-eye calibration [18], inaccurate surgical tool kinematic
data leads to an inaccurate 3D pose estimation and thereby
affects the accuracy of its back-projected 2D pixel position,
which serves as a criterion for evaluating different hand-eye
calibration strategies.
B. Challenges in accurate positioning
1) Cable-driven effects: The dVRK surgical platform,
which is a cable-driven robotic system [19], has an inherent
issue in obtaining accurate joint readings from the built-
in encoders. This is because all encoders are mounted
adjacent to actuators but distant from joints, where the actual
joint angles are estimated through transmission kinematics
[20]. However, unknown parameters such as pulley-cable
friction and nonlinearities [21] contribute to inaccuracies in
joint angle estimation, which result in dVRK joint encoder
readings not reflecting actual joint positions. These errors
in joint space subsequently affect the estimated end effector
tip pose through Denavit-Hartenberg (DH) parameters and
forward kinematics. The DH parameters here only concern
active joints.
2) Inaccurate kinematic parameters: The wear and tear of
the dVRK not only induces cable slack [22], which affects
the parameters in the transmission kinematics, resulting
inaccurate joint encoder readings, but also entails instrument
damage which leads to additional inaccuracies in the DH
parameters of the forward kinematics, causing the estimated
tool-tip pose to stray from the actual one. Another significant
source of error is due to the potentiometers, as explained in
detail in IV.
3) Other non-kinematic error sources: Other than kine-
matic factors, non-kinematic factors such as external forces
exerted onto the tool shaft and backlash between the tool
shaft and cannula, illustrated in Fig. 2, would also con-
tribute to an overall erroneous end-tip pose estimation [23],
[24]. These external forces will affect the tension of cables
associated to tool tips, leading to an error in transmission
kinematics. In addition, they will also cause a displacement
of the tool shaft because of compliance, as illustrated in Fig.
3; this displacement is not detectable by the encoders [23],
and thus positioning error accumulates.
Fig. 2. As illustrated in red (d), there is a gap between the surgical
instrument’s shaft and the cannulae. Therefore, the point of contact between
this shaft and the cannulae can change. This phenomenon is known as
backlash. Backlash causes the tool to move without being reflected by the
encoder readings. Backlash is evident in the figure, illustrated in green,
where the “S” character of Intuitive’s logo has moved to a different location,
given that the camera is static.
Fig. 3. Compliance of the surgical instrument. Similarly to backlash, this
compliance is not reflected on encoder readings, and hence not reflected in
the joint position estimation.
C. Methods for kinematics calibration
In this subsection, we gather methods that are available in
the current literature to compensate for dVRK positioning er-
rors, and we classify these in term of the specific error source
they are aiming to address, namely encoder readings, kine-
matics parameters and other non-kinematic factors. Methods
within the former category aim to estimate the current joint
positions, whereas those within the latter category aim to
force the system to reach the desired position.
1) Compensation for encoder readings: For methods that
aim to compensate encoder reading inaccuracies, we further
divide these into two classes: encoder reading calibration and
tool-tip pose estimation. Both classes recognize the nature of
the erroneous encoder readings; however, the former focuses
on finding actual joint positions in joint space, while the
latter places an emphasis on finding the actual tool-tip pose.
a) Encoder reading calibration: Methods for calibrat-
ing encoder readings follow a standardized pipeline that
involves modeling, measurement and parameter fitting [25].
To start with, a model parameterized by η, which maps
encoder readings obtained from transducers to actual joint
positions, is conceived. In the subsequent measurement stage,
robot joints are commanded to move to designated positions
while ground truth values of joint positions are gathered
via an external measurement system. Finally, different fitting
models, which can be either linear or nonlinear, are adopted
to estimate the ηthat best fits designated joint positions to
ground truth measurements.
Major differences between methods in this class are the
selection of calibration models and approaches to measuring
the ground truth. Following the calibration paradigm, Huang
et al. [24] started off using a linear model to map encoder
readings to ground truth values gathered by tracking infrared
markers mounted on the end effector with an optical camera
system, namely the NDI Polaris [26]. To better estimate and
account for the nonlinear nature of cable stretch and friction,
Hwang et al. adopted a data-driven approach to training deep
learning models that map collected readings to actual joint
positions gathered in a similar way [11].
With access to the forward kinematics of a system, which
maps encoder readings to actual joint positions, one can find
an inverse calibration model that generates encoder com-
mands that drive a robot to reach desired joint positions. Such
methods lend themselves to implementing automatic surgical
tasks [7], [11], [13], where a surgical tool is requested
to accurately move to a given pose. However, there are
several drawbacks in model-based calibration methods. First,
as pointed out in [27], model-based calibration methods are
hard to implement outside of a lab setting because of the need
for additional sensors, calibration objects, and tedious data
collection procedures. Second, an invariant calibration model
fails to accurately reflect a dynamic mapping relationship as,
e.g., the cable wears and tears over time. Third, adopting
model-based approaches requires greater efforts to find the
ground truth values of the joint positions for the 7-DoF
da Vinci robot. Although there exists numerical inverse
kinematics solvers for the SSMs and the PSMs, running
at 1.5 KHz 2, there is a lack of kinematics parameters
identification procedures. Hence the fidelity of the nominal
kinematics parameters for the disposable surgical instruments
relies on the quality of manufacture, which, however, can
be imprecise. Furthermore, the accuracy of the ground truth
measurement provided by an external sensor, a depth-sensing
camera for example, is also inevitably affected by the inaccu-
racy in camera parameters and the hand-eye transformation
matrix, as analyzed in V and VI, respectively.
b) Tool-tip pose estimation: In addition to generating
joint commands that drive a robot to reach the desired
state, there are times when the actual tool-tip pose in the
2One numerical solver is provided at https://github.com/jhu-cisst/cisst
摘要:

Caveatsonthefirst-generationdaVinciResearchKit:latenttechnicalconstraintsandessentialcalibrationsZejianCui∗,1,2,Jo˜aoCartucho∗,1,StamatiaGiannarou1,andFerdinandoRodriguezyBaena1,2Abstract—Telesurgicalroboticsystemsprovideawellestab-lishedformofassistanceintheoperatingtheater,withevidenceofgrowingupt...

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