Fuzzy Logic Based Impedance Control to Monitor on Torque under Impulsive Loading

2011 ◽  
Vol 110-116 ◽  
pp. 5345-5350
Author(s):  
Mostafa Rahimi Dizaji ◽  
Mohammad Reza Hairi Yazdi ◽  
Moteaal Asadi Shirzi
Keyword(s):  
Fuzzy Logic ◽  
Force Control ◽  
Pid Controller ◽  
Force Feedback ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Impulsive Loading ◽  
Reference Trajectory ◽  
End Effector ◽  
Supervisory System

This paper is devoted to design a control system for robot manipulator to optimize motor torque due to external impulsive loading exerted on the manipulator. Under impulsive loading, overloading may occur in the absence of any monitoring on the torque. To avoid the overloading, impedance control is proposed as a force control strategy. Here impedance control based on force feedback of which has hit the end-effector modifies the reference trajectory. In fact, instead of resisting against impulsive loading up to extreme power of the motor, the proposed design generates small movements in the direction of impact. Therefore, the motor produces less torque in comparison to the absence of impedance control. A supervisory system assisting fuzzy logic has been used to adapt impedance controller parameters with various impact conditions. The simulation result confirms the improvement of the manipulator behavior which yields sensible reduction in motor developed torque in comparison to single PID controller.

A hybrid impedance control scheme for underwater welding robots with a passive foundation in the controller domain

SIMULATION ◽  
2017 ◽  
Vol 93 (7) ◽  
pp. 619-630 ◽  
Author(s):  
Sunil Kumar ◽  
Vikas Rastogi ◽  
Pardeep Gupta
Keyword(s):  
Minimum Distance ◽  
Position Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Graph Model ◽  
Proportional Integral Derivative ◽  
End Effector ◽  
Flexible Arm ◽  
Control Scheme ◽  
Effective Stability

A hybrid impedance control scheme for the force and position control of an end-effector is presented in this paper. The interaction of the end-effector is controlled using a passive foundation with compensation gain. For obtaining the steady state, a proportional–integral–derivative controller is tuned with an impedance controller. The hybrid impedance controller is implemented on a terrestrial (ground) single-arm robot manipulator. The modeling is done by creating a bond graph model and efficacy is substantiated through simulation results. Further, the hybrid impedance control scheme is applied on a two-link flexible arm underwater robot manipulator for welding applications. Underwater conditions, such as hydrodynamic forces, buoyancy forces, and other disturbances, are considered in the modeling. During interaction, the minimum distance from the virtual wall is maintained. A simulation study is carried out, which reveals some effective stability of the system.

Robotic force control for deburring using an active end effector

Robotica ◽  
1989 ◽  
Vol 7 (4) ◽  
pp. 303-308 ◽  
Author(s):  
G. M. Bone ◽  
M. A. Elbestawi
Keyword(s):  
Control System ◽  
Force Control ◽  
Pid Controller ◽  
Closed Loop ◽  
Least Squares Method ◽  
Closed Loop Control ◽  
End Effector ◽  
Loop Control ◽  
Positioning Errors ◽  
Force Control System

SUMMARYAn active force control system for robotic deburring based on an active end effector is developed. The system utilizes a PUMA-560 six axis robot. The robot's structural dynamics, positioning errors, and the deburring cutting process are examined in detail. Based on ARMAX plant models identified using the least squares method, a discrete PID controller is designed and tested in real-time. The control system is shown to maintain the force within l N of the reference, and reduce chamfer depth errors to 0.12 mm from the 1 mm possible without closed-loop control.

On the Problem of Constrained Path Following For Manipulators

1988 ◽  
Vol 110 (4) ◽  
pp. 443-448
Author(s):  
A. Sankaranarayanan ◽  
M. Vidyasagar
Keyword(s):  
Collision Avoidance ◽  
Force Control ◽  
Robot Manipulator ◽  
Sufficient Conditions ◽  
Path Following ◽  
Necessary And Sufficient Conditions ◽  
End Effector ◽  
Circular Contour ◽  
Necessary And Sufficient

Force Control involves moving the end-effector of a robot manipulator on the surface of an object while ensuring that no other part of the manipulator collides with the object. Suppose C is a given contour to be followed. If the end-effector can move between two points a and b on C while meeting the collision avoidance requirement, we can say that a path exists between a and b. We begin by considering a planar manipulator and a circular contour and derive the necessary and sufficient conditions for a path to exist between a pair of points. By extending these ideas, sufficient conditions are derived for a noncircular contour. The advantages of a (kinematically redundant) 3-link planar manipulator over a 2-link manipulator are pointed out. Finally, we consider spatial manipulators and derive the necessary and sufficient conditions for the case where the contour lies on the surface of a sphere.

Force Control of Robot Manipulator by Neural Network Model - Experiment and Evaluation of One-Degree-of-Freedom Manipulator -

1990 ◽  
Vol 2 (4) ◽  
pp. 273-281 ◽  
Author(s):  
Masatoshi Tokita ◽  
◽  
Toyokazu Mitsuoka ◽  
Toshio Fukuda ◽  
Takashi Kurihara ◽  
...  
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Neural Network Model ◽  
Force Control ◽  
Pid Controller ◽  
Robot Manipulator ◽  
Force Sensor ◽  
Robotic Manipulator ◽  
The Neural Network ◽  
The Stability

In this paper, a force control of a robotic manipulator based on a neural network model is proposed with consideration of the dynamics of both the force sensor and objects. This proposed system consists of the standard PID controller, the gains of which are augmented and adjusted depending on objects through a process of learning. The authors proposed a similar method previously for the force control of the robotic manipulator with consideration of dynamics of objects, but without consideration of dynamics of the force sensor, showing only simulation results. This paper shows the similar structure of the controller via the neural network model applicable to the cases with consideration of both effects and demonstrates that the proposed method shows the better performance than the conventional PID type of controller, yielding to the wider range of applications, consequently. Therefore, this method can be applied to the force/compliance control problems. The effects of the number of neurons and hidden layers of the neural network model are also discussed through the simulation and experimental results as well as the stability of the control system.

Surface Tracking with Robot Force Control in Unknown Environment

2011 ◽  
Vol 328-330 ◽  
pp. 2140-2143 ◽  
Author(s):  
Er Chao Li ◽  
Zhan Ming Li
Keyword(s):  
Force Control ◽  
Force Feedback ◽  
Environmental Parameters ◽  
Tangential Direction ◽  
Reference Trajectory ◽  
Unknown Environment ◽  
Surface Tracking ◽  
Line Force ◽  
Feedback Data ◽  
Robot Force Control

Surface tracking with robot force control for position-controlled robotic manipulator is proposed. A neural network is applied to classify the unknown environment based on its dynamic response of the environment, on-line force feedback data are employed to estimate the normal and tangential directions of the unknown environment, the estimated vectors are used to generate the reference trajectory for the target impedance model. Real-time calculates the curvature of curve to be tracked to adjust the speed of the tangential direction, the reference scaling factor is determined by fuzzy reasoning according to current and forecast contact force, in order to adapt the reference trajectory generated for the changeable environmental parameters and control parameters. Simulation is conducted to verify its force tracking capability.

Force Control of a Robot Arm During Contact Task

2002 ◽  
Author(s):  
A. Yetik ◽  
V. Karadag
Keyword(s):  
Force Control ◽  
Control Algorithm ◽  
Force Feedback ◽  
Impedance Control ◽  
Mechanical Impedance ◽  
Contact Forces ◽  
Working Environment ◽  
Robot Arm ◽  
Simulation Results ◽  
End Effectors

There are extremely important applications to investigate the control of contact between the end-effectors and the object. During controlling an object, static or in motion, the robot arm should not be damaged. Forces are important in such conditions. The forces between the end-effectors and the object have to be controlled. The motion of the robot arm changes forces. Thats why, to control forces, a force kontrol algorithm must be developed. Previous conventional force control algorithms could not control the robot effectively by only considering the variation of working environment. In this study, a control algorithm strategy to achieve the desired interactions forces between the robot end-effector and the environment during contact tasks, has been developed. The surface of the object and robot are very stiff, thus contact spring coefficient Kc is very large, because of this Kc effect, the results of the forces simulation results, but we get suitable results. Study include, modelling robot arm, evaluating measured forces during contact and constructing a suitable force control algorithm, dynamics, kinematics and simulation results. In this study, we used impedans control which the surface of the object is very stiff, as known as impedance control does not try to track position and force trajectories directly, but rather to regulate the dynamic relationship between the contact forces and manipulator positions, namely the mechanical impedance. Impedance control focused on the design of a robot’s dynamic behavior as seen from the environment. In this control strategy, no hardware or software, switch is needed in the robot’s control system when the robot travels from the free motion space to the constrained space. The force feedback loop closes naturally as soon as the robot interacts with the environment, which changes the robot’s impedance as seen from the environment. By controlling the manipulator positions, and regulating their relationship to the contact forces, the manipulator can be controlled to maintain appropriate contact forces.

Impedance Control of Space Robots Using Passive Degrees of Freedom in Controller Domain

2005 ◽  
Vol 127 (4) ◽  
pp. 564-578 ◽  
Author(s):  
Pushpraj Mani Pathak ◽  
Amalendu Mukherjee ◽  
Anirvan Dasgupta
Keyword(s):  
Force Control ◽  
Degrees Of Freedom ◽  
Impedance Control ◽  
Space Structure ◽  
Degree Of Freedom ◽  
Robotic Systems ◽  
Stable Method ◽  
Space Robots ◽  
End Effector ◽  
Control Schemes

Impedance control is an efficient and stable method of providing trajectory and force control in robotic systems. The procedure by which the impedance of the manipulator is changed is a very important aspect in the design of impedance based control schemes. In this work, a scheme is presented in which the control of impedance at the interface of the end effector and the space structure is achieved by introduction of a passive degree of freedom (DOF) in the controller of the robotic system. The impedance is shown to depend upon a compensation gain for the dynamics of the passive DOF. To illustrate the methodology, an example of a two DOF planer space robot is considered.

Fractional-Order Impedance Control Design for Robot Manipulator

2021 ◽  
Author(s):  
Xiaolian Liu ◽  
Shaohua Wang ◽  
Ying Luo
Keyword(s):  
Fractional Order ◽  
Force Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Design Method ◽  
Control Design ◽  
Performance Comparison ◽  
Positioning Errors ◽  
Impedance Parameters ◽  
Mass Spring

Abstract In order to make robot manipulators work more compliantly when contacting with the environment, it is necessary to reduce the contact force caused by positioning errors. One effective way to solve this problem is impedance control, which makes the robot manipulator a second-order mass-spring-damping system in principle. In this paper, a position-based fractional-order impedance control design method is proposed for the robot manipulator force control. The end-effector/environment contact model is established, and the closed-loop system is analyzed with the reference force as input. A fractional-order impedance parameters design method is proposed for better force-control performance, which calculates and optimizes parameters through frequency-domain specifications (i.e., phase margin and gain crossover frequency) and time-domain specification (i.e., the minimum JITSE). With the Robotics ToolBox for MATLAB (RTB), the performance comparison between integer-order and fractional-order impedance controls is illustrated in simulation. The fractional-order impedance control system has a faster response, smaller overshoot, and better resistance to external disturbances from the environment.

Optimal control of a planar robot manipulator based on the Linear Quadratic Inverse-Dynamics design

2019 ◽  
Vol 2 (2) ◽  
pp. 2
Author(s):  
Denis Mosconi ◽  
Adriano Almeida Gonçalves Siqueira ◽  
Everthon Silva Fonseca
Keyword(s):  
Feedback Loop ◽  
Inverse Dynamics ◽  
Robot Manipulator ◽  
Linear Quadratic Regulator ◽  
Robotic Systems ◽  
Reference Trajectory ◽  
Linear Quadratic ◽  
End Effector ◽  
The Right

To ensure the correct positioning of the end-effector of robot manipulators is one of the most important objectives of the robotic systems control. Lack of reliability in tracking the reference trajectory, as well as in the desired final positioning compromises the quality of the task to be performed, even causing accidents. The purpose of this work was to propose an optimal controller with an inner loop based on the dynamic model of the manipulator and a feedback loop based on the Linear Quadratic Regulator, in order to ensure that the end effector is in the right place, at the right time. The controller was compared to the conventional PID, presenting better performance, both in the transient response, eliminating overshoot, and steady-state, eliminating the stationary error.

Educational Force Control Using a Modular 2-DOF Serial Robot Manipulator and Low-Cost 2-DOF Force Sensor

2019 ◽  
Author(s):  
Stephen Mascaro
Keyword(s):  
Force Control ◽  
Degrees Of Freedom ◽  
Hybrid Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Low Cost ◽  
Force Sensor ◽  
Physical Contact ◽  
Dynamic Force ◽  
Control Techniques

Abstract This paper describes a modular 2-DOF serial robotic system and accompanying experiments that have been developed to instruct robotics students in the fundamentals of dynamic force control. In prior work, we used this same robot to showcase and compare the performance of a variety of textbook techniques for dynamic motion control (i.e. fast/accurate trajectory tracking using dynamic model-based and robust control techniques). In this paper we now add a low-cost 3D-printed 2-DOF force sensor to this modular robot and demonstrate a variety of force control techniques for use when the robot is in physical contact with the environment. These include stiffness control, impedance control, admittance control, and hybrid position/force control. Each of these various force control schemes can be first simulated and then experimentally implemented using a MATLAB/Simulink real-time interface. The two-degrees of freedom are just enough to demonstrate how the manipulator Jacobian can be used to implement directional impedances in operational space, and to demonstrate how hybrid control can implement position and force control in different axes. This paper will describe the 2-DOF robot system including the custom force sensor, illustrate the various force control methods that can be implemented, and demonstrate sample results from these experiments.

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