An Adaptive Approach to Motion and Force Control of Multiple Coordinated Robots

1993 ◽  
Vol 115 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Yan-Ru Hu ◽  
A. A. Goldenberg
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Lyapunov Stability Theory ◽  
Internal Force ◽  
Object Motion ◽  
Tracking Accuracy ◽  
Unknown Parameters ◽  
Adaptive Law ◽  
Control Scheme ◽  
Force Tracking

In this paper an approach to motion and force control of multiple coordinated robots, based on an adaptive scheme, is developed. The approach can be used to control the motion of an object held by the robots, the contact force between the object and the environment, and the internal force which do not contribute to the object motion and contact force. Three subsystem error equations are generated, i.e., position error subsystem, contact force error subsystem, and internal force error subsystem. The adaptive law is derived to estimate the unknown parameters of the multiple coordinated robots, the object, and the environment in terms of the three error subsystem equations. The convergence of the position, contact, internal force errors, and parameter errors is analyzed based on the Lyapunov stability theory. The paper shows that the adaptive control scheme improves the position, and the internal and contact force tracking accuracy for a class of robotic systems with uncertain knowledge of the dynamic model.

An Approach to Motion and Force Control of Coordinated Robot Arms in the Presence of Joint Flexibility

1994 ◽  
Vol 116 (3) ◽  
pp. 326-335 ◽  
Author(s):  
Yan-Ru Hu ◽  
Andrew A. Goldenberg
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Lyapunov Stability Theory ◽  
Internal Force ◽  
System Stability ◽  
Motion Controller ◽  
Flexible Joint ◽  
Robot Arms ◽  
Simulation Results ◽  
And Control

A system consisting of several flexible joint robot arms is studied in this paper. The paper addresses the motion and force control problem of such systems. A coordinating controller, consisting of a motion controller, contact force controller, and internal force controller, is designed to distribute the load between the coordinated flexible joint robot arms, and control the motion of the object, the internal force and contact force between the object and the environment, as well generate the desired joint elastic force. The system stability is analyzed based on Lyapunov stability theory. It is shown that with the proposed controller the motion and force control variables can be regulated to track asymptotically their desired trajectories. Simulation results are given to illustrate the performance of the proposed controller.

scholarly journals Suppress Vibration on Robotic Polishing with Impedance Matching

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 59
Author(s):  
Junjie Dai ◽  
Chin-Yin Chen ◽  
Renfeng Zhu ◽  
Guilin Yang ◽  
Chongchong Wang ◽  
...  
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Impedance Control ◽  
Impedance Matching ◽  
Industrial Robots ◽  
Contact Phase ◽  
Dynamic Tracking ◽  
Force Tracking ◽  
The Difference ◽  
End Effectors

Installing force-controlled end-effectors on the end of industrial robots has become the mainstream method for robot force control. Additionally, during the polishing process, contact force stability has an important impact on polishing quality. However, due to the difference between the robot structure and the force-controlled end-effector, in the polishing operation, direct force control will have impact during the transition from noncontact to contact between the tool and the workpiece. Although impedance control can solve this problem, industrial robots still produce vibrations with high inertia and low stiffness. Therefore, this research proposes an impedance matching control strategy based on traditional direct force control and impedance control methods to improve this problem. This method’s primary purpose is to avoid force vibration in the contact phase and maintain force–tracking performance during the dynamic tracking phase. Simulation and experimental results show that this method can smoothly track the contact force and reduce vibration compared with traditional force control and impedance control.

Contact Stability and Contact Safety of a Magnetic Resonance Imaging-Guided Robotic Catheter Under Heart Surface Motion

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Ran Hao ◽  
E. Erdem Tuna ◽  
M. Cenk Çavuşoğlu
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Motion Prediction ◽  
Resonance Imaging ◽  
Contact Stability ◽  
Heart Motion ◽  
Control Scheme ◽  
Control Schemes ◽  
Position Feedback ◽  
Contact Force Control

Abstract Contact force quality is one of the most critical factors for safe and effective lesion formation during catheter based atrial fibrillation ablation procedures. In this paper, the contact stability and contact safety of a novel magnetic resonance imaging (MRI)-actuated robotic cardiac ablation catheter subject to surface motion disturbances are studied. First, a quasi-static contact force optimization algorithm, which calculates the actuation needed to achieve a desired contact force at an instantaneous tissue surface configuration is introduced. This algorithm is then generalized using a least-squares formulation to optimize the contact stability and safety over a prediction horizon for a given estimated heart motion trajectory. Four contact force control schemes are proposed based on these algorithms. The first proposed force control scheme employs instantaneous heart position feedback. The second control scheme applies a constant actuation level using a quasi-periodic heart motion prediction. The third and the last contact force control schemes employ a generalized adaptive filter-based heart motion prediction, where the former uses the predicted instantaneous position feedback, and the latter is a receding horizon controller. The performance of the proposed control schemes is compared and evaluated in a simulation environment.

scholarly journals RISE-Based Composite Adaptive Control of Electro-Hydrostatic Actuator with Asymptotic Stability

Machines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 181
Author(s):  
Yaowen Ge ◽  
Xiaowei Yang ◽  
Wenxiang Deng ◽  
Jianyong Yao
Keyword(s):  
Adaptive Control ◽  
Tracking Performance ◽  
System Stability ◽  
Unmodeled Dynamics ◽  
Tracking Accuracy ◽  
Adaptive Law ◽  
Control Scheme ◽  
Highly Nonlinear ◽  
Composite Adaptive Control ◽  
Parameter Adaptive

The electro-hydrostatic actuator (EHA), the actuator of electric drive and hydraulic transmission, is competitive since it is small in size, light in weight and high in power density. However, the existence of the velocity loop error of servo motors, unmodeled dynamics and highly nonlinear uncertainties restrict the improvement of the tracking accuracy of the EHA system. In order to achieve high-precision motion control of EHAs, a RISE-based composite adaptive control scheme is proposed in this paper. In the proposed composite adaptive control design, a novel parameter adaptive law is synthesized to compensate for the parametric uncertainties and a robust integral of the sign of error (RISE) feedback is utilized to suppress the adverse effects caused by the lumped disturbances, including the velocity loop error of a servo motor and other unmodeled dynamics. The synthesized parameter adaptive law possesses the advantage of fast convergence, which is beneficial to achieve transient tracking performance improvement. In addition, the proposed controller is more suitable for practical applications since it is chattering free. The closed-loop system stability analysis shows that the proposed control scheme guarantees an excellent asymptotic tracking performance. Finally, comparative simulations are conducted to verify the high-performance nature of the proposed controller.

scholarly journals Contact Force Control of Three-Dimensional Flexible Manipulator

2020 ◽  
Author(s):  
Minoru Sasaki ◽  
Shunta Ito ◽  
Daiki Maeno ◽  
Waweru Njeri ◽  
Muguro Josephh ◽  
...  
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Three Dimensional ◽  
Flexible Manipulator ◽  
Force Tracking ◽  
Feedback Method ◽  
Three Degrees Of Freedom ◽  
Contact Force Control

This paper proposes a contact force controller for a constrained flexible manipulator in three-dimensional motion. This controller used the conversion formula obtained empirically and experimental results showed the effectiveness of the proposed contact force controller. First, the manipulator was operated with the tip of the second link restrained, then, time response of the root strain, joint angles and contact force were used to derive the relational between the three quantities. The effectiveness of the relational expression was verified by conducting a target contact force tracking experiment by inputting the angle from the relational expression. The contact force control using the strain feedback method was proposed with the strain amount estimated from the target contact force as the target value, and its effectiveness was verified by experiments. From the results obtained, controller using the strain feedback method was designed for the purpose of controlling the contact force at the tip of a flexible manipulator with two links and three degrees of freedom that performs three-dimensional spatial motion, and its effectiveness was shown by comparison with the contact force feedback method.

scholarly journals ADAPTIVE SYNCHRONIZATION FOR RÖSSLER AND CHUA'S CIRCUIT SYSTEMS

2002 ◽  
Vol 12 (07) ◽  
pp. 1579-1597 ◽  
Author(s):  
A. S. HEGAZI ◽  
H. N. AGIZA ◽  
M. M. EL-DESSOKY
Keyword(s):  
Phase Space ◽  
Direct Method ◽  
Lyapunov Stability Theory ◽  
Adaptive Synchronization ◽  
Unknown Parameters ◽  
State Variable ◽  
Chua Circuit ◽  
Control Scheme ◽  
Stable Means ◽  
Error System

This study addresses the adaptive synchronization of Rössler and Chua circuit systems with unknown parameters. By using Lyapunov stability theory the adaptive synchronization law with a single-state variable feedback is derived, such that the trajectory of the two systems are globally stabilized to an equilibrium point of the uncontrolled system (globally stable means that the method of the solution is restricted in area of phase space i.e. globally in a subset of a phase space with bounded zero volume). We use the Lyapunov direct method to study the asymptotic stability of the solutions of error system. Numerical simulations are given to explain the effectiveness of the proposed control scheme.

ADAPTIVE SWITCHING CONTROL AND SYNCHRONIZATION OF CHAOTIC SYSTEMS WITH UNCERTAINTIES

2005 ◽  
Vol 15 (10) ◽  
pp. 3381-3390 ◽  
Author(s):  
JING YAO ◽  
ZHI-HONG GUAN ◽  
DAVID J. HILL
Keyword(s):  
Chaotic Systems ◽  
Lyapunov Stability Theory ◽  
Switching Control ◽  
Control Law ◽  
Unknown Parameters ◽  
Control Scheme ◽  
Control And Synchronization ◽  
Adaptive Switching Control ◽  
Adaptive Control Law ◽  
Synchronization Problems

In this paper, a new adaptive switching control scheme is presented to solve control and synchronization problems. Based on Lyapunov stability theory, an adaptive control law is applied to globally stabilize chaotic systems and achieve states synchronization of two chaotic systems whose dynamics are subjected to the system disturbances and/or some unknown parameters. Simulation examples, the chaotic Chen's system and Chua's circuit, are given to show the feasibility and effectiveness of the proposed theory and method.

scholarly journals Adaptive Reinforcement Learning-Enhanced Motion/Force Control Strategy for Multirobot Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Phuong Nam Dao ◽  
Duy Khanh Do ◽  
Dinh Khue Nguyen
Keyword(s):  
Reinforcement Learning ◽  
Force Control ◽  
Tracking Control ◽  
Dynamic Control ◽  
Additional Term ◽  
Control Law ◽  
Force Coefficient ◽  
Constraint Force ◽  
Control Scheme ◽  
Force Tracking

This paper presents an adaptive reinforcement learning- (ARL-) based motion/force tracking control scheme consisting of the optimal motion dynamic control law and force control scheme for multimanipulator systems. Specifically, a new additional term and appropriate state vector are employed in designing the ARL technique for time-varying dynamical systems with online actor/critic algorithm to be established by minimizing the squared Bellman error. Additionally, the force control law is designed after obtaining the computation of constraint force coefficient by the Moore–Penrose pseudo-inverse matrix. The tracking effectiveness of the ARL-based optimal control is verified in the closed-loop system by theoretical analysis. Finally, simulation studies are conducted on a system of three manipulators to validate the physical realization of the proposed optimal tracking control design.

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