scholarly journals Adaptive Robust Motion Control of Direct-Drive DC Motors with Continuous Friction Compensation

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Jianyong Yao ◽  
Guichao Yang ◽  
Zongxia Jiao ◽  
Dawei Ma
Keyword(s):  
Motion Control ◽  
High Accuracy ◽  
Friction Model ◽  
Control Input ◽  
Continuous Control ◽  
Direct Drive ◽  
Accuracy Control ◽  
Tracking Accuracy ◽  
Robust Controller ◽  
Output Tracking

Uncertainties including the structured and unstructured, especially the nonlinear frictions, always exist in physical servo systems and degrade their tracking accuracy. In this paper, a practical method named adaptive robust controller (ARC) is synthesized with a continuous differentiable friction model for high accuracy motion control of a direct-drive dc motor, which results in a continuous control input and thus is more suitable for application. To further reduce the noise sensitivity and improve the tracking accuracy, a desired compensation version of the proposed adaptive robust controller is also developed and its stability is guaranteed by a proper robust law. The proposed controllers not only account for the structured uncertainties (e.g., parametric uncertainties) but also for the unstructured uncertainties (e.g., unconsidered nonlinear frictions). Furthermore, the controllers theoretically guarantee a prescribed output tracking transient performance and final tracking accuracy in both structured and unstructured uncertainties while achieving asymptotic output tracking in the absence of unstructured uncertainties, which is very important for high accuracy control of motion systems. Extensive comparative experimental results are obtained to verify the high-performance nature of the proposed control strategies.

Output Feedback Robust Control of Direct Current Motors With Nonlinear Friction Compensation and Disturbance Rejection

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
Jianyong Yao ◽  
Zongxia Jiao ◽  
Dawei Ma
Keyword(s):  
Direct Current ◽  
High Performance ◽  
Controller Design ◽  
High Accuracy ◽  
Friction Model ◽  
Practical Implementation ◽  
Accuracy Control ◽  
External Disturbances ◽  
Output Tracking ◽  
Dc Motors

High accuracy tracking control of direct current (DC) motors is concerned in this paper. A continuously differentiable friction model is adopted to account for the friction nonlinearities, which allows more flexible and suitable practical implementation. Since only output signal is available for measurement, an extended state observer (ESO) is designed to provide precise estimates of the unmeasurable state together with external disturbances, which facilitates the controller design without any transformations. The global stability of the controller is ensured via a certain robust feedback law. The resulting controller theoretically guarantees a prescribed tracking performance in general, while achieving asymptotic output tracking in the absence of time-varying disturbances, which is very important for high accuracy control of motion systems. Comparative experimental results are obtained to verify the high-performance nature of the proposed control strategy.

Motion Control of Ultra-High-Speed Manipulator with a Flexible Link Based on Dynamically Coupled Driving

2006 ◽  
Vol 18 (5) ◽  
pp. 598-607 ◽  
Author(s):  
Tomoari Maruyama ◽  
◽  
Chunquan Xu ◽  
Aiguo Ming ◽  
Makoto Shimojo
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Wrist Joint ◽  
High Accuracy ◽  
Human Motion ◽  
Golf Club ◽  
Direct Drive ◽  
Flexible Link ◽  
Ultra High Speed ◽  
Drive Motor

We have developed a golf robot whose swing simulates human motion. The design concept is to realize ultra-high-speed dynamic manipulation using a dexterous mechanism. The robot consists of a shoulder joint with a high-power direct-drive motor and a wrist joint with a low-power direct-drive motor. High-speed golf swings are realized by a sort of motion control, called dynamically-coupled driving which compensates for the lack of drive in the wrist joint. In this paper a new model accounting for golf club flexibility with all parameters identified in experiments was developed. Based on this, we generated and implemented trajectories for different criteria. Experimental results confirmed the high accuracy of motion control and the feasibility of golf club flexibility in ultra-high-speed manipulation.

Tribo-dynamic analysis and motion control of a rotating manipulator based on the load and temperature dependent friction model

2020 ◽  
pp. 135065012095494
Author(s):  
Qi Yan ◽  
Rui Li ◽  
Xianghui Meng
Keyword(s):  
Motion Control ◽  
Sliding Mode ◽  
Static Friction ◽  
Friction Model ◽  
Continuous Control ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Terminal Sliding Mode ◽  
Joint Friction ◽  
Adaptive Property

Joint friction has a significant influence on the dynamics and motion control of manipulators. However, the friction effect is often omitted or simplified in previous studies. In this paper, we establish the dynamics model of a single joint in a rotating industrial manipulator taking detailed friction effects into consideration and propose a new control algorithm for the friction compensation purpose. Firstly, the manipulator dynamics modeling is carried out employing a recently-proposed extended static friction model, which depicts load and temperature influence on Coulomb, Stribeck and viscous terms. Moreover, based on the established dynamics model, the paper presents a new adaptive fast nonsingular terminal sliding mode (AFNTSM) controller. The proposed approach has the advantages of continuous control inputs, fast convergence rate, no singularity and great robustness against disturbances. Furthermore, its adaptive property does not require any prior knowledge of the upper bound of the uncertainties. Finally, the proposed controller is applied to the manipulator joint trajectory tracking problem with varying friction subject to load and temperature changes. The numerical simulation verifies the effectiveness of our proposed method and its advantages over other controllers.

Indirect Adaptive Robust Control of Uncertain Systems With Unknown Asymmetric Input Deadband Using a Smooth Inverse

2009 ◽  
Author(s):  
Amit Mohanty ◽  
Bin Yao
Keyword(s):  
Parameter Estimation ◽  
Tracking Error ◽  
Estimation Algorithm ◽  
Adaptive Robust Control ◽  
Control Input ◽  
Robust Controller ◽  
Output Tracking ◽  
L2 Norm ◽  
Parameter Estimation Algorithm ◽  
Asymptotic Tracking

In this paper, we present an indirect adaptive robust controller (IARC) for output tracking of a class of uncertain nonlinear systems with unknown input asymmetric deadband in presence of uncertain nonlinearities and parametric uncertainties. Most of the parameter adaptation algorithms, such as, gradient-type and least squares-type require that the unknown parameters of a system appear in affine with known regressor functions globally. However, deadband nonlinearity can not be represented in those global linear parametric form. Therefore, the existing parameter estimation algorithms for deadband focus on some approximate linear parametric model. Hence, even in absence of any other uncertain nonlinearities and disturbances, these algorithms can never achieve asymptotic tracking. Departing from those approximate deadband estimation, we design an indirect parameter estimation algorithm with online condition monitoring. This parameter estimation algorithm in conjunction with a well-designed robust controller and a deadband inverse function can be used to obtain asymptotic tracking without restoring to discontinuous control law. With this strong result in our repertoire, we proceed to design a smooth deadband inverse (SDI) function to avoid certain problems during implementation, e.g, control input chattering and significant appearance of high-frequency dynamics. The effect of such an approximation on the L2-norm of output tracking error is analytically determined. We also show that while operating away from the deadband, the proposed controller even with an SDI can achieve asymptotic tracking. In presence of disturbances and other uncertain nonlinearities, the proposed IARC controller attains guaranteed transient performance and final tracking accuracy.

scholarly journals Force-Free Control for Direct Teaching of a Surgical Assistant Robot End Effector with Wire-Driven Bidirectional Telescopic Mechanism

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3498
Author(s):  
Youqiang Zhang ◽  
Cheol-Su Jeong ◽  
Minhyo Kim ◽  
Sangrok Jin
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Friction Model ◽  
Surgical Instruments ◽  
Control Input ◽  
End Effector ◽  
Motor Current ◽  
Direct Teaching ◽  
End Effectors ◽  
Teaching Operation

This paper shows the design and modeling of an end effector with a bidirectional telescopic mechanism to allow a surgical assistant robot to hold and handle surgical instruments. It also presents a force-free control algorithm for the direct teaching of end effectors. The bidirectional telescopic mechanism can actively transmit force both upwards and downwards by staggering the wires on both sides. In order to estimate and control torque via motor current without a force/torque sensor, the gravity model and friction model of the device are derived through repeated experiments. The LuGre model is applied to the friction model, and the static and dynamic parameters are obtained using a curve fitting function and a genetic algorithm. Direct teaching control is designed using a force-free control algorithm that compensates for the estimated torque from the motor current for gravity and friction, and then converts it into a position control input. Direct teaching operation sensitivity is verified through hand-guiding experiments.

Obstacle avoidance control of a human-in-the-loop mobile robot system using harmonic potential fields

Robotica ◽  
2017 ◽  
Vol 36 (4) ◽  
pp. 463-483 ◽  
Author(s):  
C. Ton ◽  
Z. Kan ◽  
S. S. Mehta
Keyword(s):  
Mobile Robot ◽  
Obstacle Avoidance ◽  
Sliding Mode ◽  
Harmonic Potential ◽  
Control Allocation ◽  
Control Input ◽  
Continuous Control ◽  
Control Effort ◽  
Human In The Loop ◽  
Allocation Function

SUMMARYThis paper considers applications where a human agent is navigating a semi-autonomous mobile robot in an environment with obstacles. The human input to the robot can be based on a desired navigation objective, which may not be known to the robot. Additionally, the semi-autonomous robot can be programmed to ensure obstacle avoidance as it navigates the environment. A shared control architecture can be used to appropriately fuse the human and the autonomy inputs to obtain a net control input that drives the robot. In this paper, an adaptive, near-continuous control allocation function is included in the shared controller, which continuously varies the control effort exerted by the human and the autonomy based on the position of the robot relative to obstacles. The developed control allocation function facilitates the human to freely navigate the robot when away from obstacles, and it causes the autonomy control input to progressively dominate as the robot approaches obstacles. A harmonic potential field-based non-linear sliding mode controller is developed to obtain the autonomy control input for obstacle avoidance. In addition, a robust feed-forward term is included in the autonomy control input to maintain stability in the presence of adverse human inputs, which can be critical in applications such as to prevent collision or roll-over of smart wheelchairs due to erroneous human inputs. Lyapunov-based stability analysis is presented to guarantee finite-time stability of the developed shared controller, i.e., the autonomy guarantees obstacle avoidance as the human navigates the robot. Experimental results are provided to validate the performance of the developed shared controller.

Control for Robots With Braking Actuators in a Uniform Force Field

2015 ◽  
Author(s):  
Erlend Framstad ◽  
Mark D. Bedillion
Keyword(s):  
Force Field ◽  
Control Strategy ◽  
Coulomb Friction ◽  
Energy Equation ◽  
High Accuracy ◽  
Friction Model ◽  
Second Law ◽  
Inclined Plane ◽  
Position And Orientation ◽  
Coulomb Friction Model

This paper concerns the control strategy of a robot with controllable brakes placed in a uniform force field. Without loss of generality this force field is assumed to be gravity, and the robot to be an object resting on an inclined plane. The controller’s objective is then to use the brakes to lead the robot into a desired position and orientation. The system’s dynamics were derived from Newton’s second law with a Coulomb friction model. The controller was derived from geometric properties and the energy equation. The controller was then tested using Matlab and Simulink on the dynamics that were derived. The results of the simulation shows high accuracy even with some disturbances, and uncalibrated parameters.

Disturbance observer-based motion control of direct drive motors

1991 ◽  
Vol 6 (3) ◽  
pp. 553-559 ◽  
Author(s):  
S. Komada ◽  
M. Ishida ◽  
K. Ohnishi ◽  
T. Hori
Keyword(s):  
Motion Control ◽  
Disturbance Observer ◽  
Direct Drive
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