Robust Impedance Control for Robot Manipulator

1991 ◽  
Vol 3 (6) ◽  
pp. 470-474
Author(s):  
Yoshiharu Nishida ◽  
◽  
Takashi Harada ◽  
Nobuaki Imamura ◽  
Nobuo Kimura
Keyword(s):  
Disturbance Observer ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Joint Space ◽  
Experimental Results ◽  
Control Methods ◽  
Robust Controller ◽  
End Effector ◽  
Cartesian Space ◽  
Modeling Errors

In most robust impedance control methods, error factors such as disturbances and modeling errors in the joint space are dealt with. However, the dynamics for an end effector of the manipulator in the Cartesian space is more important than that of the manipulator in the joint space. In this paper, error factors are described in the Cartesian space, and the influence of these factors on the dynamics of the end-effector are considered. A robust controller is designed using either feedback of impedance error or a disturbance observer based on the Cartesian space, and its effectiveness is confirmed through experimental results.

scholarly journals A Power-Assisted Cart with the Optimal Assistance Ratio and Disturbance Observer-Based Methods for Walking Assistance Applications

2021 ◽  
Vol 11 (3) ◽  
pp. 1079
Author(s):  
Xianglong Wan ◽  
Jiaxin Ma ◽  
Yichi Zhang ◽  
Takahiro Endo ◽  
Fumitoshi Matsuno
Keyword(s):  
Healthy Subjects ◽  
Disturbance Observer ◽  
The Elderly ◽  
Operational Efficiency ◽  
Motor Output ◽  
Experimental Results ◽  
Control Methods ◽  
Road Surfaces

In this paper, we propose two control methods for driving a power-assisted cart made for walking assistance for the elderly. The optimal assistance ratio (OAR) and disturbance observer-based (DOB) methods properly adjust the motor output of the cart with high operational efficiency in response to changes in the environment. Healthy subjects walked with the cart on several road surfaces under various conditions, and the experimental results indicate the high operational efficiency of the two proposed methods. Meanwhile, their drawbacks are also discussed herein. The two methods can be used separately or combined according to the application. The OAR method is more suitable for indoor use, while the DOB method is applicable for outdoor applications. Combining these two methods could overcome the mentioned drawbacks.

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.

Robot Manipulation Using Virtual Compliance Control

2000 ◽  
Vol 12 (5) ◽  
pp. 567-576 ◽  
Author(s):  
Hisaaki Hirabayashi ◽  
◽  
Koichi Sugimoto ◽  
Atsuko Enomoto ◽  
Ichirou Ishimaru ◽  
...  
Keyword(s):  
Real Time ◽  
Position Control ◽  
Control Method ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Experimental Results ◽  
Velocity Control ◽  
Compliance Control ◽  
Robot Hands ◽  
Control Response

Experimental results proved that a unified method of impedance control, already presented as virtual compliance control, can make a robot manipulator without any special mechanism perform various patterns of motion, corresponding to the specified software parameters of the control method. Outcomes demonstrated are as follows. (1) The proposed control method can change the characteristics of spring constant and dashpot constant, that is impedance, of 6 degree of freedom (translational: 3 , rotational: 3) of the robot hand. (2) The change of characteristics mentioned above in (1) can be treated equivalently in both translational and rotational. (3) The change of characteristics mentioned above in (1) and (2) can be implemented in real time. (4) The proposed control method can change the characteristics of transient response in velocity control of 6-d.o.f. of the robot hands. (5) The change of characteristics mentioned above in (4) can be treated equivalently both translationally and rotationally. (6) The change of characteristics mentioned above in (4) and (5) can be implemented in real time. (7) The proposed control method can make impedance control applied to one axis, and position control applied to other axis simultaneously, as to 6-d.o.f. of the robot hands. (8) Experimental results mentioned above in (1) - (7) imply the following advantage and disadvantage; advantage: a unified control method that can perform various patterns of motion by specifying software parameters, disadvantage: control response is not necessarily precise that is because proposed control method is base on not dynamics but kinematics.

Sliding Mode Hybrid Impedance Control of Robot Manipulators Interacting With Unknown Environments Using VSMRC Method

2012 ◽  
Author(s):  
Aghil Jafari ◽  
Reza Monfaredi ◽  
Mehdi Rezaei ◽  
Ali Talebi ◽  
Saeed Shiry Ghidary
Keyword(s):  
Control System ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Variable Structure ◽  
Structure Model ◽  
Robust Controller ◽  
Control Approach ◽  
Chattering Effect

In the present paper, the objective of hybrid impedance control is specified and a robust hybrid impedance control approach is proposed. Based on the concept of hybrid control, the task space is decomposed into position and force controlled subspaces. Impedance control is used in the position controlled subspace. Desired inertia and damping are applied in the force controlled subspace to meliorate the dynamic behavior of robot manipulator. Robust controller using the variable structure model reaching control (VSMRC) is introduced that can realize the objective impedance in the sliding mode in finite time. In order to overcome the chattering effect due to sliding mode approach, fuzzy logic methodology is employed in the control system. In addition, the reaching transient response is undertaken with prescribed quality. Simulating the control system for a 6DOF PUMA560 robot confirms the validity and effectiveness of the proposed control system.

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.

Research on Painting Robot Manipulator for Irregular Components in Reproducing Cartridge

2011 ◽  
Vol 121-126 ◽  
pp. 1358-1362
Author(s):  
Qian Qian Chen ◽  
Xiu Ting Wei ◽  
Jiang Hai Lin ◽  
Gang Li
Keyword(s):  
Inverse Problem ◽  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Joint Space ◽  
Forward Problem ◽  
Cartesian Space ◽  
Painting Robot

In order to implement the surface painting automation of irregular components of reproducing cartridge, a painting robot manipulator with four degrees of freedom is carried out in this paper. Kinematics forward problem and inverse problem of the manipulator are firstly formulated and then painting trajectory is described by adopting the structure of endpoints and line-style. Furthermore, painting trajectory is generated in both joint space and Cartesian space according to robot’s trajectory planning principle.

scholarly journals End effector position calculation with the ANN for tapping machine

2021 ◽  
Vol 9 (3B) ◽  
Author(s):  
Gullu Akkas ◽  
◽  
Ihsan Korkut ◽  
Murat Tolga Ozkan ◽  
◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Position Control ◽  
Robot Manipulator ◽  
High Reliability ◽  
Future Research ◽  
Robot Arm ◽  
Labor Costs ◽  
End Effector ◽  
Cartesian Space ◽  
End Point

Nowadays, manufacturers give importance to the production of machines that allow for faster production, reduce labor costs, and minimize operation errors to meet the increasing demand. The search for such machines leads the manufacturing sector to automation. In this study, an automation-supported tapping machine prototype was manufactured. Kinematic equations were used for determining the location of the end effector in Cartesian space, whereas inverse kinematic equations were used for angular positions in joint space relative to positions in Cartesian space. Based on the results of the kinematic equations, the data obtained in certain positions were taught to the system through ANN. The position values for the angles known through the artificial intelligence algorithm were taught to the system. Then, the position coordinates to be reached by this manipulator, which has four degrees of freedom, for the intermediate position coordinate values through artificial neural networks (ANN) have been obtained. It is expected that the device controlled by artificial intelligence will not be affected by the variables in parameter or force changes requiring high working performance. With the control of the positions through ANN, it has been ensured that the position control of the tapping robot manipulator is predicted based on artificial intelligence techniques depending on the angle values of the limbs, and the robot is prevented from going to a position that is on a different trajectory. Accordingly, the robot arm has been made controllable with ANN techniques. With ANN modelling, the position of the end point to perform the tapping process was estimated with high reliability. For future research, a rough simulation was made to see whether the end point would go to a different position in space.

scholarly journals An Extended DMPs framework for Decoupled Quaternions Learning and generalization

2021 ◽  
Author(s):  
Zhiwei Liao ◽  
Fei Zhao ◽  
Gedong Jiang ◽  
Xuesong Mei
Keyword(s):  
Riemannian Manifolds ◽  
Gaussian Mixture ◽  
Joint Space ◽  
Robot Learning ◽  
Learning From Demonstration ◽  
End Effector ◽  
Mixture Regression ◽  
Cartesian Space ◽  
Dynamic Movement ◽  
Dynamic Movement Primitives

Abstract Dynamic Movement Primitives (DMPs) as a robust and efficient framework has been studied widely for robot learning from demonstration. Classical DMPs framework mainly focuses on the movement learning in Cartesian or joint space, and can't properly represent end-effector orientation. In this paper, we present an Extended DMPs framework (EDMPs) both in Cartesian space and Riemannian manifolds for Quaternion-based orientations learning and generalization. Gaussian Mixture Model and Gaussian Mixture Regression are adopted as the initialization phase of EDMPs to handle multi-demonstrations and obtain their mean and covariance. Additionally, some evaluation indicators including reachability and similarity are defined to characterize the learning and generalization abilities of EDMPs. Finally, the quaternion-based orientations are successfully transferred from human to the robot, and a real-world experiment is conducted to verify the effectiveness of the proposed method. The experimental results reveal that the presented approach can learn and generalize multi-space parameters under multi-demonstrations.

A Cartesian Workspace Generator for Robot Arm Workcell Obstacle Collision Avoidance

1991 ◽  
Author(s):  
Tak-Lai Daryl Luk ◽  
John E. Sneckenberger
Keyword(s):  
Free Space ◽  
Robot Manipulator ◽  
Joint Space ◽  
Robot Arm ◽  
New Approach ◽  
Cartesian Space ◽  
Manipulator Arm ◽  
Arm Motion ◽  
Space Boundary ◽  
Crank Mechanism

Abstract Most of the methods for planning collision-free robot manipulator arm morions to accomplish collision-free end-effector paths are based on explicit representation of the sub-space of the robot work space that is free of arm motion with obstacles collision. This sub-space is called the robot arm free space and most path planners represent this free space in joint space. If the robot arm free space is represented in joint space, then each point in the free space corresponds to a robot arm configuration for which no arm-obstacle collision occurs. This paper presents a new approach for generating the robot arm free space for an articulated type robot manipulator. This approach uses an oscillating slider crank mechanism for defining the free-space boundary when certain arm-obstacle collisions occurs. The robot arm free space, importantly, is generated in Cartesian space instead of joint space.

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