Robust controls for flexible joint robots: a single link case study with unknown joint stiffness parameter

2002 ◽  
Author(s):  
Y. Aoustin
Keyword(s):  
Joint Stiffness ◽  
Stiffness Parameter ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Single Link

scholarly journals Extended and Unscented Kalman Filtering Applied to a Flexible-Joint Robot with Jerk Estimation

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad Ali Badamchizadeh ◽  
Iraj Hassanzadeh ◽  
Mehdi Abedinpour Fallah
Keyword(s):  
Initial Conditions ◽  
Covariance Matrices ◽  
Flexible Joints ◽  
Velocity Measurements ◽  
Lagrange Equations ◽  
Robust Nonlinear Control ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Simulation Results

Robust nonlinear control of flexible-joint robots requires that the link position, velocity, acceleration, and jerk be available. In this paper, we derive the dynamic model of a nonlinear flexible-joint robot based on the governing Euler-Lagrange equations and propose extended and unscented Kalman filters to estimate the link acceleration and jerk from position and velocity measurements. Both observers are designed for the same model and run with the same covariance matrices under the same initial conditions. A five-bar linkage robot with revolute flexible joints is considered as a case study. Simulation results verify the effectiveness of the proposed filters.

scholarly journals Cascaded Control of Flexible-Joint Robots Based on Sliding-Mode Estimator Approach

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Genliang Xiong ◽  
Jingxin Shi ◽  
Haichu Chen
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Joint Stiffness ◽  
Perturbation Approach ◽  
Regular Form ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Highly Nonlinear ◽  
Position Controller ◽  
High Bandwidth

The inherent highly nonlinear coupling and system uncertainties make the controller design for a flexible-joint robot extremely difficult. The goal of the control of any robotic system is to achieve high bandwidth, high accuracy of trajectory tracking, and high robustness, whereby the high bandwidth for flexible-joint robot is the most challenging issue. This paper is dedicated to design such a link position controller with high bandwidth based on sliding-mode technique. Then, two control approaches ((1) extended-regular-form approach and (2) the cascaded control structure based on the sliding-mode estimator approach) are presented for the link position tracking control of flexible-joint robot, considering the dynamics of AC-motors in robot joints, and compared with the singular perturbation approach. These two-link position controllers are tested and verified by the simulation studies with different reference trajectories and under different joint stiffness.

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