
cent advances in robotic tactile perception (Ba et al.,
2018), our method utilizes the CatBoostClassifier to
analyze interaction forces and motion patterns during
contact tasks. This contrasts with traditional model-
based approaches that require explicit physical mod-
eling of each surface type, which becomes imprac-
tical when dealing with unknown or variable materi-
als (Suomalainen et al., 2022; Elguea-Aguinaco et al.,
2023). By training on comprehensive simulation data
from a 7-DOF Franka Panda robot executing repeti-
tive contact motions, our system learns to distinguish
subtle differences in dynamic behavior across mate-
rials - a capability particularly valuable for industrial
applications like precision assembly or recycling au-
tomation, among others (Paz et al., 2022).
Our validation focused on precisely those chal-
lenging scenarios where traditional methods falter –
particularly in distinguishing material pairs with sim-
ilar frictional coefficients but different compliance
profiles (e.g., brass vs. Teflon, rubber vs. silicone).
We propose analysis of temporal patterns in joint
torques and end-effector vibrations during continu-
ous operation tests looking to obtain a significant im-
provement over model-based approaches that showed
23% higher error rates under identical conditions (Ba
et al., 2018). This performance gap highlights the
advantage of data-driven parameter estimation in dy-
namic industrial environments where surface proper-
ties may vary unpredictably (Kroemer et al., 2021).
Despite these advancements, three limitations
warrant consideration. First, while our proposed clas-
sifier excels on known materials (e.g., metals, poly-
mers), as it will be shown, its accuracy drops by 12-
15% for unseen surface textures – a challenge also ob-
served in (Ba et al., 2018)’s work. Second, the current
implementation requires 3-5 contact cycles to stabi-
lize predictions, limiting applicability in time-critical
tasks. Finally, friction variability due to environmen-
tal factors (i.e., temperature, wear) was not fully mod-
eled in our simulations. These open challenges will
guide our future work toward embedding real-time
surface adaptation in physical robotic cells.
This work demonstrates that machine learning-
enhanced impedance control can effectively bridge
the gap between theoretical modeling and real-world
surface variability in industrial robotics. By com-
bining the CatBoost Classifier’s high-accuracy ma-
terial prediction (99% on known surfaces) with
theoretically-sound parameter tuning, we address a
critical limitation in traditional approaches. Although
current limitations in generalization to novel textures
persist, our framework provides a foundation for en-
abling safer human-robot collaboration through more
responsive contact behavior (Paz et al., 2022). Future
work will focus on real-world validation with multi-
modal sensing (vision, force) to overcome the texture-
dependency challenge identified in Section IV.
2 METHODOLOGY
This Section details the modeling, simulation, data
acquisition, and machine learning methods used to
develop a predictive contact-surface classification
system for industrial robotic tasks. The study was
based on the development of a predictive system for
the estimation of contact surfaces in repetitive tasks.
First, a simulation analysis of the robotic system
was performed, implementing an impedance control
system with the objective of improving the interac-
tion of the robot with different surfaces, in this case
straight surfaces. Impedance control has been widely
applied as a sound and safe solution for robotic tasks
in which the robot interacts with the environment.
It basically refers to the extension and generaliza-
tion of the second-order scalar mechanical system
m ¨x +c ˙x +kx = f , consisting of a mass, a damper, and
a spring with an external force, respectively (Villani
and De Schutter, 2008).
Starting from the dynamic equation of motion of
a robotic manipulator, a definition for joint space
impedance control can be imposed and described
M(q)
¨
q(t) + C
˙
q(t) + Kq(t) = τ
τ
τ
ext
(1)
where q is the vector of the n joint angles, M is the
(n × n) inertia mass matrix, and the damping (C) and
stiffness (K) matrices are all expressed in the joint
space of the robot.
All the modeling and simulation of the robot was
performed using MATLAB/Simulink (MathWorks,
2022), allowing us a deep understanding and analy-
sis of the robot behavior and response of the over-
all system. Since an impedance controller defined in
the Cartesian space was implemented, the control pa-
rameters needed to be chosen in a safe manner, al-
ways having in mind the stability and joint behav-
ior for the entire manipulation task. After perform-
ing the corresponding joint-based analysis (Campos
et al., 2024) and several tests (without any inertia
reshaping), we chose to use the following parame-
ters (Cartesian D
C
damping, and K
C
stiffness matri-
ces) according to the joint configuration of the robot,
all in SI units: D
C
= diag(100, 100, 100, 18, 13, 15),
K
C
= diag(3500, 3500, 3500, 100, 100, 100).
These parameters were validated in the simulator
with the robot and proved to perform correctly for the
given trajectories.
Subsequently, tests were performed under differ-
ent operating conditions, i.e., each trajectory was
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