Dynamics and Control of Vertical-Plane Motion for an Electrohydraulically Actuated Single-Flexible-Link Arm

1992 ◽  
Vol 114 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Liang-Wey Chang
Keyword(s):  
Motion Tracking ◽  
Inverse Dynamics ◽  
Low Cost ◽  
Vertical Plane ◽  
Plane Motion ◽  
Flexible Link ◽  
Actuator Dynamics ◽  
Nonlinear Motion ◽  
Dynamics And Control ◽  
And Control

A research tool was developed for the dynamics and control of a single-flexible-link arm based on the Equivalent Rigid Link System (ERLS) dynamic model and the inverse dynamics of the arm and the actuator. The arm moved in a vertical plane and was actuated by an electrohydraulic motor. The required torque was computed based on the inverse dynamics of the ERLS model. The driving current was then predicted by the inverse actuator dynamics. This paper also presents a 16-bit microcomputer-based low-cost implementation of a nonlinear motion tracking control. The dynamic behavior of the control system was studied through the computer simulation and the experiment. Furthermore, the superiority of the flexible-body control was also proved through the comparison to the rigid-body control.

Robust Stabilization of Large Amplitude Ship Rolling in Beam Seas

1997 ◽  
Vol 122 (1) ◽  
pp. 108-113 ◽  
Author(s):  
Shyh-Leh Chen ◽  
Steven W. Shaw ◽  
Hassan K. Khalil ◽  
Armin W. Troesch
Keyword(s):  
Large Amplitude ◽  
Controller Design ◽  
Sliding Mode ◽  
Robust Stabilization ◽  
Vertical Plane ◽  
Singularly Perturbed Systems ◽  
Strongly Nonlinear ◽  
Beam Seas ◽  
Dynamics And Control ◽  
And Control

The dynamics and control of a strongly nonlinear 3-DOF model for ship motion are investigated. The model describes the roll, sway, and heave motions occurring in a vertical plane when the vessel is subjected to beam seas. The ship is installed with active antiroll tanks as a means of preventing large amplitude roll motions. A robust state feedback controller for the pumps is designed that can handle model uncertainties, which arise primarily from unknown hydrodynamic loads. The approach for the controller design is a combination of sliding mode control and composite control for singularly perturbed systems, with the help of the backstepping technique. It is shown that this design can effectively control roll motions of large amplitude, including capsize prevention. Numerical simulation results for an existing fishing vessel, the twice-capsized Patti-B, are used to verify the analysis. [S0022-0434(00)02701-5]

Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System

2013 ◽  
Author(s):  
Frank Fresconi ◽  
Ilmars Celmins ◽  
Mark Ilg ◽  
James Maley
Keyword(s):  
Low Cost ◽  
Dynamics And Control ◽  
And Control

2 DOF Compliant 3D-PLE System Demonstrating Fundamentals of Vibrations and Passive Vibration Isolation

2020 ◽  
Author(s):  
Niko Giannakakos ◽  
Ayse Tekes ◽  
Tris Utschig
Keyword(s):  
Degrees Of Freedom ◽  
Engineering Students ◽  
Vibration Isolation ◽  
Low Cost ◽  
Educational Systems ◽  
Primary System ◽  
Laboratory Equipment ◽  
Dynamics And Control ◽  
3D Printed ◽  
And Control

Abstract Mechanical engineering students often learn the fundamentals of vibrations along with the time response of underdamped, critically damped, and overdamped systems in machine dynamics and vibrations courses without any validation or visualization through hands-on experimental learning activities. As these courses are highly theoretical, students find it difficult to connect theory to practical fundamentals such as modeling of a mechanical system, finding components of the system using experimental data, designing a system to achieve a desired response, or designing a passive vibration isolator to reduce transmitted vibrations on a primary system. Further, available educational laboratory equipment demonstrating vibrations, dynamics and control is expensive, bulky, and not portable. To address these issues, we developed a low-cost, 3D printed, portable laboratory equipment (3D-PLE) system consisting of primary and secondary carts, rail, linear actuator, Arduino, and compliant flexures connecting the carts. Most of the educational systems consist of a mass limited to 1DOF motion and multi-degrees of freedom systems can be created using mechanical springs. However, in real-world applications oscillations in a system are not necessarily due to mechanical springs. Anything flexible, or thin and long, can be represented by a spring as seen in torsional systems. We incorporated 3D printed and two monolithically designed rigid arms connected with a flexure hinge of various stiffness. The carts are designed in a way such that two flexible links can be attached from both sides and allow more loads to be added on each cart. The system can be utilized to demonstrate fundamentals of vibrations and test designs of passive isolators to dampen the oscillations of the primary cart.

Projectile Roll Dynamics and Control with a Low-Cost Maneuver System

2014 ◽  
Vol 51 (2) ◽  
pp. 624-627 ◽  
Author(s):  
Frank Fresconi ◽  
Ilmars Celmins ◽  
Mark Ilg ◽  
James Maley
Keyword(s):  
Low Cost ◽  
Dynamics And Control ◽  
And Control

A novel rigid–flexible link combined lunar sampler and its basic dynamics and control

2014 ◽  
Vol 38 ◽  
pp. 41-47 ◽  
Author(s):  
Yun Ling ◽  
Wei Lu ◽  
Changcheng Wu ◽  
Aiguo Song ◽  
Chao Feng
Keyword(s):  
Flexible Link ◽  
Dynamics And Control ◽  
And Control

On Dynamics and Control of Multi-Link Flexible Manipulators

1995 ◽  
Vol 117 (2) ◽  
pp. 134-142 ◽  
Author(s):  
W. Gawronski ◽  
C.-H. C. Ih ◽  
S. J. Wang
Keyword(s):  
Rigid Body ◽  
Inverse Dynamics ◽  
Linear Time ◽  
Flexible Manipulator ◽  
Flexible Manipulators ◽  
Link Length ◽  
Joint Torques ◽  
Control Approach ◽  
Dynamics And Control ◽  
And Control

This paper presents solutions of dynamics, inverse dynamics, and control problems of multi-link flexible manipulators. In deriving the manipulator dynamics, flexible deformations are assumed to be small in relation to the link length, angular rates of the links are assumed to be much smaller than their fundamental frequencies, and nonlinear terms (centrifugal and Coriolis forces) in the flexible manipulator model are assumed to be the same as those in the rigid body model. Flexible displacements are measured with respect to the rigid body configuration, obtained from its rigid body inverse kinematics. As a result, a linear time-varying system is obtained. The inverse dynamics problem consists of determination of joint torques for a given tip trajectory such that joint angles in the flexible configuration are equal to the angles in the rigid body configuration. The manipulator control system consists of the feedforward compensation and feedback control loops. Simulation results of a two-link space crane with a large payload show that the performance of this linearized dynamics and control approach is accurate, and at the same time is robust when subjected to parameter variations during slew operations.

Modeling the Spatial Dynamics of Robotic Manipulators with Flexible Links and Joint Clearances

1993 ◽  
Vol 115 (4) ◽  
pp. 839-847 ◽  
Author(s):  
T. Kakizaki ◽  
J. F. Deck ◽  
S. Dubowsky
Keyword(s):  
Control System ◽  
Spatial Dynamics ◽  
Dynamic Effects ◽  
Nonlinear Functions ◽  
Detailed Model ◽  
Actuator Dynamics ◽  
Dynamics And Control ◽  
Joint Clearances ◽  
And Control ◽  
System Characteristics

A dynamic modeling method is presented for spatial elastic manipulators that can account for a number of their realistic properties, including bearing clearances, actuator dynamics, and control system characteristics. Forces in the bearing clearances are modeled by nonlinear functions of the links’ relative motions and the internal geometry of the connection, or by experimentally measured properties. A detailed model is given for a revolute connection with radial and axial clearances. Results obtained for a SCARA manipulator show that the combined dynamic effects of bearing clearances, link elasticity, and control system characteristics can significantly degrade the system’s performance.

Long Range Six Degree-of-Freedom Magnetic Levitation Using Low Cost Sensing and Control

2020 ◽  
Vol 32 (3) ◽  
pp. 683-691
Author(s):  
Peter Berkelman ◽  
Yu-Sheng Lu ◽  
◽  
Keyword(s):  
Motion Tracking ◽  
Permanent Magnets ◽  
Magnetic Levitation ◽  
Low Cost ◽  
Position Sensing ◽  
Levitation System ◽  
Magnetic Levitation System ◽  
And Function ◽  
Six Degree Of Freedom ◽  
And Control

We have developed a magnetic levitation system which uses an array of cylindrical actuation coils and a set of three position sensing photodiode assemblies for controlled levitation of a moving platform of permanent magnets. The novelty of this system is that low cost, standard off-the-shelf commodity hardware and software components are used for position sensing and feedback control, rather than costly motion tracking sensing systems and controllers. The design and function of the system are described and controlled motion in all directions is demonstrated through motion ranges of 30 mm horizontal and 20 mm vertical translation, and 26° of roll and 43° of yaw rotation.

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