2,310 research outputs found
A decentralized proportional-integral sliding mode tracking controller for a 2 D.O.F robot arm
Trajectory tracking with high accuracy is a very challenging topic in direct drive robot control. This is due to the nonlinearities and input couplings present in the dynamics of the arm. This paper deals with the tracking control of a class of direct-drive robot manipulators. A robust Proportional-Integral (PI) sliding mode control law is derived so that the robot trajectory tracks a desired trajectory as closely as possible despite the highly non-linear and coupled dynamics. The controller is designed using the decentralized approaches. Application to a two degree of freedom direct drive robot arm is considered
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Robust nonlinear decentralized control of robot manipulators
A new decentralized nonlinear controller for Robot Manipulators is
presented in this thesis. Based on concepts of Lyapunov stability theory and
some control ideas proposed in [3]-[7], we obtain continuous nonlinear
decentralized control laws which guarantee position and velocity tracking to
within an arbitrarily small error.
Assumptions based on physical constraints of manipulators are made to
guarantee the existence of the controller and asymptotic stability of the closed
loop system. Simulations show how well this rather simple control scheme works
on two of the links of the Puma 560 Manipulator.
The main contribution of this thesis is that it extends the results of a
class of complex centralized control algorithms to the decentralized robust
control of interconnected nonlinear subsystems like robot manipulators
Robust Cooperative Manipulation without Force/Torque Measurements: Control Design and Experiments
This paper presents two novel control methodologies for the cooperative
manipulation of an object by N robotic agents. Firstly, we design an adaptive
control protocol which employs quaternion feedback for the object orientation
to avoid potential representation singularities. Secondly, we propose a control
protocol that guarantees predefined transient and steady-state performance for
the object trajectory. Both methodologies are decentralized, since the agents
calculate their own signals without communicating with each other, as well as
robust to external disturbances and model uncertainties. Moreover, we consider
that the grasping points are rigid, and avoid the need for force/torque
measurements. Load distribution is also included via a grasp matrix
pseudo-inverse to account for potential differences in the agents' power
capabilities. Finally, simulation and experimental results with two robotic
arms verify the theoretical findings
A Stability Analysis for the Acceleration-based Robust Position Control of Robot Manipulators via Disturbance Observer
This paper proposes a new nonlinear stability analysis for the
acceleration-based robust position control of robot manipulators by using
Disturbance Observer (DOb). It is shown that if the nominal inertia matrix is
properly tuned in the design of DOb, then the position error asymptotically
goes to zero in regulation control and is uniformly ultimately bounded in
trajectory tracking control. As the bandwidth of DOb and the nominal inertia
matrix are increased, the bound of error shrinks, i.e., the robust stability
and performance of the position control system are improved. However, neither
the bandwidth of DOb nor the nominal inertia matrix can be freely increased due
to practical design constraints, e.g., the robust position controller becomes
more noise sensitive when they are increased. The proposed stability analysis
provides insights regarding the dynamic behavior of DOb-based robust motion
control systems. It is theoretically and experimentally proved that
non-diagonal elements of the nominal inertia matrix are useful to improve the
stability and adjust the trade-off between the robustness and noise
sensitivity. The validity of the proposal is verified by simulation and
experimental results.Comment: 9 pages, 9 figures, Journa
Cooperative Adaptive Control for Cloud-Based Robotics
This paper studies collaboration through the cloud in the context of
cooperative adaptive control for robot manipulators. We first consider the case
of multiple robots manipulating a common object through synchronous centralized
update laws to identify unknown inertial parameters. Through this development,
we introduce a notion of Collective Sufficient Richness, wherein parameter
convergence can be enabled through teamwork in the group. The introduction of
this property and the analysis of stable adaptive controllers that benefit from
it constitute the main new contributions of this work. Building on this
original example, we then consider decentralized update laws, time-varying
network topologies, and the influence of communication delays on this process.
Perhaps surprisingly, these nonidealized networked conditions inherit the same
benefits of convergence being determined through collective effects for the
group. Simple simulations of a planar manipulator identifying an unknown load
are provided to illustrate the central idea and benefits of Collective
Sufficient Richness.Comment: ICRA 201
Pose consensus based on dual quaternion algebra with application to decentralized formation control of mobile manipulators
This paper presents a solution based on dual quaternion algebra to the
general problem of pose (i.e., position and orientation) consensus for systems
composed of multiple rigid-bodies. The dual quaternion algebra is used to model
the agents' poses and also in the distributed control laws, making the proposed
technique easily applicable to time-varying formation control of general
robotic systems. The proposed pose consensus protocol has guaranteed
convergence when the interaction among the agents is represented by directed
graphs with directed spanning trees, which is a more general result when
compared to the literature on formation control. In order to illustrate the
proposed pose consensus protocol and its extension to the problem of formation
control, we present a numerical simulation with a large number of free-flying
agents and also an application of cooperative manipulation by using real mobile
manipulators
Persepsi pelajar terhadap persekitaran fizikal bilik kuliah dia blok FPTV dan blok UTHM dari aspek pengajaran dan pembelajaran
Kajian ini adalah untuk mengenal pasti persepsi pelajar terhadap persekitaran fizikal bilik kuliah di antara blok FPTV dengan blok UTHM (di luar FPTV). Antara faktor tersebut ialah kebersihan, pencahayaan, pengudaraan, susunan perabot dan kemudahan. Reka bentuk kajian yang digunakan dalam kajian ini ialah kajian tinjauan berbentuk kuantitatif. Instrumen kajian yang dipilih ialah set borang kaji selidik. Seramai 313 orang pelajar Fakulti Pendidikan Teknikal dan Vokasional telah dipilih sebagai responden di dalam kajian ini..
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