Acceleration Profiles for Causal Solutions of the Inverse Dynamics Approach to the Control of Single Link Flexible Arms

1991 ◽  
Vol 113 (4) ◽  
pp. 752-754 ◽  
Author(s):  
H. C. Moulin ◽  
E. Bayo
Keyword(s):  
Inverse Dynamics ◽  
Peak Torque ◽  
Discrete Models ◽  
Actuation Time ◽  
End Point ◽  
Single Link ◽  
Flexible Arms

A scheme for the design of rest-to-rest acceleration profiles to be used in the inverse dynamics approach to the control of the end-point of single link flexible arms is described. The scheme uses linear discrete models, and a stable pole-cancellation method to obtain acceleration profiles that yield inverse dynamics torques with the same supports as that of the end-point acceleration profiles; it allows for a design which reaches a balance between overshoot, peak torque and actuation time.

On the Accuracy of End-Point Trajectory Tracking for Flexible Arms by Noncausal Inverse Dynamic Solutions

1991 ◽  
Vol 113 (2) ◽  
pp. 320-324 ◽  
Author(s):  
H. Moulin ◽  
E. Bayo
Keyword(s):  
Flexible Structures ◽  
Open Loop ◽  
Open Loop Control ◽  
Inverse Dynamic ◽  
Element Discretization ◽  
Loop Control ◽  
End Point ◽  
Flexible Arm ◽  
Single Link ◽  
Flexible Arms

The problem of open-loop control of the end-point trajectory of a single-link flexible arm by an inverse dynamic solution is addressed in this paper. A finite element discretization of the system is used to obtain a set of ordinary differential equations describing the motion. Theoretical difficulties pertaining to the inverse problem for flexible structures are exposed, and it is shown that a noncausal solution for the actuating torque enables a tracking of an arbitrary tip displacement with any desired accuracy.

Inverse Dynamics of a Flexible Robot Arm by Optimal Control

1993 ◽  
Vol 115 (2) ◽  
pp. 289-293 ◽  
Author(s):  
T. Kokkinis ◽  
M. Sahraian
Keyword(s):  
Optimal Control ◽  
Inverse Dynamics ◽  
Robot Arm ◽  
Flexible Robot ◽  
Joint Torques ◽  
Practical Applications ◽  
End Point ◽  
Point Tracking ◽  
Flexible Arms ◽  
High Frequency Content

The problem of end-point positioning of flexible arms is discussed. Because of the nonminimum phase nature of the problem, inversion fails to produce bounded joint torques. Bounded noncausal joint torques for achieving the task of end-point tracking for a multilink arm are found using optimal control theory. The torques obtained have no high-frequency content, and are suitable for practical applications. The method is illustrated by simulation of a single-link arm, for which stability and robustness considerations for design are given.

Design of Trajectories With Physical Constraints for Very Lightweight Single Link Flexible Arms

2006 ◽  
Author(s):  
Francisco Ramos ◽  
Vicente Feliu ◽  
Ismael Payo
Keyword(s):  
Design Process ◽  
Internal Control ◽  
Elastic Limit ◽  
Feedforward Control ◽  
Objective Method ◽  
Maximum Deflection ◽  
Robotic Arms ◽  
Physical Constraints ◽  
Single Link ◽  
Flexible Arms

This communication deals with feedforward control of light, flexible robotic arms. In particular we develop a new, objective method to design a family of trajectories that can be used as modified inputs which cancel the tip vibrations during the robot manoeuvres. This method takes into account the constraints encountered in real actuators (motors), such as a maximum motor torque, and those due to the mechanical limits of the link, such as the maximum deflection before reaching the elastic limit of the link. Parameters of the internal control of the actuators are also derived from the design process, gaining the fastest performance without saturating the motor. Lastly, we show some experimental results which clearly demonstrate the benefits of the new trajectories by comparing them to a linear one.

Real-Time Algorithm of the Inverse Dynamics of Flexible Arms

1992 ◽  
Vol 25 (20) ◽  
pp. 199-203
Author(s):  
Wang Guoli ◽  
Lu Guizhang
Keyword(s):  
Real Time ◽  
Inverse Dynamics ◽  
Time Algorithm ◽  
Flexible Arms

End-point position control of a single-link arm using shape memory alloy actuators

2003 ◽  
Vol 217 (8) ◽  
pp. 871-882 ◽  
Author(s):  
Y M Han ◽  
C J Park ◽  
S B Choi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Governing Equation ◽  
Position Control ◽  
Sliding Mode ◽  
Point Position ◽  
End Point ◽  
Single Link ◽  
Point Trajectories ◽  
Sma Spring

This article presents a novel type of actuating mechanism for the end-point trajectory control of a single-link system. The actuating mechanism consists of two sets of shape memory alloy (SMA) springs to generate a desired link motion of the system. The governing equation of motion is derived using the Lagrangian equation and Jacobian matrix. The actuator dynamic of the SMA spring is then empirically identified and incorporated into the governing equation. A sliding mode controller that is robust to parameter variations such as the time constant of the SMA actuator is formulated to achieve desired end-point trajectories of the single-link system. The controller is experimentally realized and tracking control performances for various end-point position trajectories are presented. In addition, the simulated control results are compared with the measured ones in order to validate the proposed control model.

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