699 research outputs found
Oscillation Damping Control of Pendulum-like Manipulation Platform using Moving Masses
This paper presents an approach to damp out the oscillatory motion of the
pendulum-like hanging platform on which a robotic manipulator is mounted. To
this end, moving masses were installed on top of the platform. In this paper,
asymptotic stability of the platform (which implies oscillation damping) is
achieved by designing reference acceleration of the moving masses properly. A
main feature of this work is that we can achieve asymptotic stability of not
only the platform, but also the moving masses, which may be challenging due to
the under-actuation nature. The proposed scheme is validated by the simulation
studies.Comment: IFAC Symposium on Robot Control (SYROCO) 201
Nonlinear control of a class of underactuated systems
A theoretical framework is established for the dynamics and control of underactuated systems, defined as systems which have fewer inputs than degrees of freedom. Control system formulation of underactuated systems is addressed and the class of second-order nonholonomic systems is identified. Controllability and stabilizability results are derived for this class of underactuated systems. Examples are included to illustrate the result
Reinforcement Learning Adaptive PID Controller for an Under-actuated Robot Arm
Abstract: An adaptive PID controller is used to control of a two degrees of freedom under actuated manipulator. An actor-critic based reinforcement learning is employed for tuning of parameters of the adaptive PID controller. Reinforcement learning is an unsupervised scheme wherein no reference exists to which convergence of algorithm is anticipated. Thus, it is appropriate for real time applications. Controller structure and learning equations as well as update rules are provided. Simulations are performed in SIMULINK and performance of the controller is compared with NARMA-L2 controller. The results verified good performance of the controller in tracking and disturbance rejection tests
Motion Control of an Underactuated 2-DOF Robotic Manipulator
This paper deals with the motion control of the end effector of a 2-DOF linkage type underactuated robotic manipulator. A simulation procedure is implemented for the motion control in which actuation and braking actions were applied on the two joints of the manipulator subsequently, hence moving the end effector in a point to point manner through the desired path. From the results obtained, it was found that the percentage error in trajectory mainly does not exceed (1%). In some specific points on the trajectory, error reached its maximum value which was found to be (3.64%). In general, these error values are almost acceptable, although an effort will be achieved in future work to reduce this error and improve the design. Keywords: Underactuated Manipulators, Motion Control, Simulation
Observer-based Controller Design for Oscillation Damping of a Novel Suspended Underactuated Aerial Platform
In this work, we present a novel actuation strategy for a suspended aerial
platform. By utilizing an underactuation approach, we demonstrate the
successful oscillation damping of the proposed platform, modeled as a spherical
double pendulum. A state estimator is designed in order to obtain the
deflection angles of the platform, which uses only onboard IMU measurements.
The state estimator is an extended Kalman filter (EKF) with intermittent
measurements obtained at different frequencies. An optimal state feedback
controller and a PD+ controller are designed in order to dampen the
oscillations of the platform in the joint space and task space respectively.
The proposed underactuated platform is found to be more energy-efficient than
an omnidirectional platform and requires fewer actuators. The effectiveness of
our proposed system is validated using both simulations and experimental
studies.Comment: 7 pages, 11 figures, Accepted for publication to ICRA 202
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