Adaptive force and position control of rigid-link flexible-joint SCARA robots

2002 ◽  
Author(s):  
G. Mester
Keyword(s):  
Position Control ◽  
Flexible Joint ◽  
Rigid Link

Flexible-Joint Humanoid Balancing Augmentation via Full-State Feedback Variable Impedance Control

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Emmanouil Spyrakos-Papastavridis ◽  
Jian S. Dai
Keyword(s):  
State Feedback ◽  
Position Control ◽  
Impedance Control ◽  
Humanoid Robots ◽  
Flexible Joint ◽  
Model Free ◽  
Floating Base ◽  
Full State ◽  
Full State Feedback ◽  
Series Elastic Actuators

Abstract This paper attempts to address the quandary of flexible-joint humanoid balancing performance augmentation, via the introduction of the Full-State Feedback Variable Impedance Control (FSFVIC), and Model-Free Compliant Floating-base VIC (MCFVIC) schemes. In comparison to rigid-joint humanoid robots, efficient balancing control of compliant bipeds, powered by Series Elastic Actuators (or harmonic drives), requires the design of more sophisticated controllers encapsulating both the motor and underactuated link dynamics. It has been demonstrated that Variable Impedance Control (VIC) can improve robotic interaction performance, albeit by introducing energy-injecting elements that may jeopardize closed-loop stability. To this end, the novel FSFVIC and MCFVIC schemes are proposed, which amalgamate both collocated and non-collocated feedback gains, with power-shaping signals that are capable of preserving the system's stability/passivity during VIC. The FSFVIC and MCFVIC stably modulate the system's collocated state gains to augment balancing performance, in addition to the non-collocated state gains that dictate the position control accuracy. Utilization of arbitrarily low-impedance gains is permitted by both the FSFVIC and MCFVIC schemes propounded herein. An array of experiments involving the COmpliant huMANoid reveals that significant balancing performance amelioration is achievable through online modulation of the full-state feedback gains (VIC), as compared to utilization of invariant impedance control.

An Approach for the Dynamics of Robotic Manipulators With Structural Flexibility of Links and Joints

1997 ◽  
Author(s):  
J. Kövecses ◽  
R. G. Fenton ◽  
W. L. Cleghorn
Keyword(s):  
Equations Of Motion ◽  
Robotic Manipulators ◽  
Structural Flexibility ◽  
Flexible Link ◽  
Dynamic Effects ◽  
Flexible Joint ◽  
Modeling And Analysis ◽  
Discrete Parameter ◽  
Rigid Link ◽  
Different Types

Abstract In this paper, an approach is presented for the dynamic modeling and analysis of robotic manipulators having structural flexibility in the links and joints. The formulation allows the user to include different types of flexibilities, as required. This approach includes the dynamic effects of joint driving systems by considering the mass and moments of inertia of their elements, the rotor-link interactions, and the gear reduction ratios; all of which can have significant influences on the behavior of the manipulator. Both distributed-discrete and discretized-discrete parameter models of a robot can be analysed. In the discretized-discrete case, dynamic equations of motion are developed for four model types: rigid link - rigid joint, rigid link - flexible joint, flexible link - rigid joint, and flexible link - flexible joint. An example of a two-link manipulator is considered. Simulation results are presented for different models (flexible joint - rigid link, rigid joint - flexible link, flexible joint - flexible link) of the manipulator. The computations show the influence of joint and link flexibilities on the manipulator performance.

Theoretical investigation into the modelling of a flexible beam with drive-line compliance

2002 ◽  
Vol 216 (8) ◽  
pp. 813-829 ◽  
Author(s):  
D J Purdy
Keyword(s):  
Theoretical Investigation ◽  
Transfer Functions ◽  
Flexible Beam ◽  
Direct Drive ◽  
Flexible Link ◽  
Line Model ◽  
Flexible Joint ◽  
Rigid Link ◽  
Dimensional Parameters ◽  
Weapons Systems

A comparison is made between the dynamics of three possible models for a flexible link and drive-line as used in some robotic or weapons systems. The three models considered are: model 1, a flexible link with compliance in the drive-line; model 2, flexible link with direct drive; and model 3, rigid link with drive-line compliance (flexible joint). Non-dimensional parameters are suggested for the models and comparisons are made between them, by examining the transfer functions poles (resonances) and zeros (anti-resonances). From the study, recommendations are made as to the suitability of the three models for different applications.

Proxy based position control for flexible joint robot with link side energy feedback

2019 ◽  
Vol 121 ◽  
pp. 103272 ◽  
Author(s):  
Lei Sun ◽  
Wen Zhao ◽  
Wei Yin ◽  
Ning Sun ◽  
Jingtai Liu
Keyword(s):  
Position Control ◽  
Flexible Joint ◽  
Energy Feedback

scholarly journals Discrete-Time Sliding Mode Control Coupled with Asynchronous Sensor Fusion for Rigid-Link Flexible-Joint Manipulators

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Guangyue Xue ◽  
Xuemei Ren ◽  
Kexin Xing ◽  
Qiang Chen
Keyword(s):  
Sensor Fusion ◽  
Discrete Time ◽  
Tracking Control ◽  
Sliding Mode ◽  
Estimation Error ◽  
Tracking Error ◽  
Sampling Rate ◽  
Experimental Studies ◽  
Flexible Joint ◽  
Rigid Link

This paper proposes a novel discrete-time terminal sliding mode controller (DTSMC) coupled with an asynchronous multirate sensor fusion estimator for rigid-link flexible-joint (RLFJ) manipulator tracking control. A camera is employed as external sensors to observe the RLFJ manipulator’s state which cannot be directly obtained from the encoders since gear mechanisms or flexible joints exist. The extended Kalman filter- (EKF-) based asynchronous multirate sensor fusion method deals with the slow sampling rate and the latency of camera by using motor encoders to cover the missing information between two visual samples. In the proposed control scheme, a novel sliding mode surface is presented by taking advantage of both the estimation error and tracking error. It is proved that the proposed controller achieves convergence results for tracking control in the theoretical derivation. Simulation and experimental studies are included to validate the effectiveness of the proposed approach.

scholarly journals Global adaptive partial state feedback tracking control of rigid-link flexible-joint robots

Robotica ◽  
2000 ◽  
Vol 18 (3) ◽  
pp. 325-336 ◽  
Author(s):  
W.E. Dixon ◽  
E. Zergeroglu ◽  
D.M. Dawson ◽  
M.W. Hannan
Keyword(s):  
State Feedback ◽  
Robot Manipulator ◽  
Parametric Uncertainty ◽  
State Feedback Control ◽  
Velocity Measurements ◽  
Linear Filters ◽  
Flexible Joint ◽  
Rigid Link ◽  
Flexible Joint Robots ◽  
Partial State

This paper presents a solution to the global adaptive partial state feedback control problem for rigid-link, flexible-joint (RLFJ) robots. The proposed tracking controller adapts for parametric uncertainty throughout the entire mechanical system while only requiring link and actuator position measurements. A nonlinear filter is employed to eliminate the need for link velocity measurements while a set of linear filters is utilized to eliminate the need for actuator velocity measurements. A backstepping control strategy is utilized to illustrate global asymptotic link position tracking. An output feedback controller that adapts for parametric uncertainty in the link dynamics of the robot manipulator is presented as an extension. Experimental results are provided as verification of the proposed controller.

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