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.

scholarly journals Research and Ground Verification of the Force Compliance Control Method for Space Station Manipulator

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Bingshan Hu ◽  
Huanlong Chen ◽  
Liangliang Han ◽  
Hongliu Yu
Keyword(s):  
Real Time ◽  
Contact Force ◽  
Control Algorithm ◽  
Control Method ◽  
Impedance Control ◽  
Space Station ◽  
Gravity Compensation ◽  
Compliance Control ◽  
Experiment Platform ◽  
Dual Arm

The space station manipulator does lots of tasks with contact force/torque on orbit. To ensure the safety of the space station and the manipulator, the contact force/torque of manipulator must be controlled. Based on analyzing typical tasks’ working flows and force control requirements, such as ORU (orbit replacement unit) changeout and dual arm collaborative payload transport, an impedance control method based on wrist 6 axis force/torque feedback is designed. For engineering implementation of the impedance control algorithm, the discretization method and impedance control parameters selection principle are also studied. To verify the compliance control algorithm, a ground experiment platform adopting industrial manipulators is developed. In order to eliminate the influence of gravity, a real-time gravity compensation algorithm is proposed. Then, the correctness of real-time gravity compensation and force compliance control algorithm is verified on the experiment platform. Finally, the ORU replacement and dual arm collaborative payload transport experiments are done. Experimental results show that the force compliance control method proposed in this paper can control the contact force and torque at the end of the manipulator when executing typical tasks.

scholarly journals A model reference adaptive variable impedance control method for robot

2021 ◽  
Vol 336 ◽  
pp. 03005
Author(s):  
Xinchao Sun ◽  
Lianyu Zhao ◽  
Zhenzhong Liu
Keyword(s):  
Real Time ◽  
Tracking Control ◽  
Control Method ◽  
Impedance Control ◽  
Tracking Error ◽  
Reference Trajectory ◽  
Control Parameters ◽  
Model Reference ◽  
Force Tracking ◽  
Model Reference Adaptive

As a simple and effective force tracking control method, impedance control is widely used in robot contact operations. The internal control parameters of traditional impedance control are constant and cannot be corrected in real time, which will lead to instability of control system or large force tracking error. Therefore, it is difficult to be applied to the occasions requiring higher force accuracy, such as robotic medical surgery, robotic space operation and so on. To solve this problem, this paper proposes a model reference adaptive variable impedance control method, which can realize force tracking control by adjusting internal impedance control parameters in real time and generating a reference trajectory at the same time. The simulation experiment proves that compared with the traditional impedance control method, this method has faster force tracking speed and smaller force tracking error. It is a better force tracking control method.

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.

A Modular 2-DOF Serial Robot Manipulator for Education in Robot Control

2016 ◽  
Author(s):  
Stephen Mascaro
Keyword(s):  
Robot Control ◽  
Inverse Dynamics ◽  
Position Control ◽  
Sliding Mode ◽  
Feedforward Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Force Sensor ◽  
Control Techniques ◽  
Serial Robot

This paper describes a modular 2-DOF serial robot manipulator and accompanying experiments that have been developed to introduce students to the fundamentals of robot control. The robot is designed to be safe and simple to use, and to have just enough complexity (in terms of nonlinear dynamics) that it can be used to showcase and compare the performance of a variety of textbook robot control techniques including computed torque feedforward control, inverse dynamics control, robust sliding-mode control, and adaptive control. These various motion control schemes can be easily implemented in joint space or operational space using a MATLAB/Simulink real-time interface. By adding a simple 2-DOF force sensor to the end-effector, the robot can also be used to showcase a variety of force control techniques including impedance control, admittance control, and hybrid force/position control. The 2-DOF robots can also be used in pairs to demonstrate control architectures for multi-arm coordination and master/slave teleoperation. This paper will describe the 2-DOF robot and control hardware/software, illustrate the spectrum of robot control methods that can be implemented, and show sample results from these experiments.

scholarly journals Unified Switching between Active Flying and Perching of a Bioinspired Robot Using Impedance Control

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Shanshan Du ◽  
Heping Chen ◽  
Yong Liu ◽  
Runting Hu
Keyword(s):  
Animal Behavior ◽  
Position Control ◽  
Control Method ◽  
Impedance Control ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Control Methods ◽  
Prior Work ◽  
Control Approach ◽  
Three Dimensional Space

Currently, a bottleneck problem for battery-powered microflying robots is time of endurance. Inspired by flying animal behavior in nature, an innovative mechanism with active flying and perching in the three-dimensional space was proposed to greatly increase mission life and more importantly execute tasks perching on an object in the stationary way. In prior work, we have developed some prototypes of flying and perching robots. However, when the robots switch between flying and perching, it is a challenging issue to deal with the contact between the robot and environment under the traditional position control without considering the stationary obstacle and external force. Therefore, we propose a unified impedance control approach for bioinspired flying and perching robots to smoothly contact with the environment. The dynamic model of the bioinspired robot is deduced, and the proposed impedance control method is employed to control the contact force and displacement with the environment. Simulations including the top perching and side perching and the preliminary experiments were conducted to validate the proposed method. Both simulation and experimental results validate the feasibility of the proposed control methods for controlling a bioinspired flying and perching robot.

Operational “Feel” Adjustment by Reinforcement Learning for a Power-Assisted Positioning Task

2009 ◽  
Vol 3 (6) ◽  
pp. 671-680 ◽  
Author(s):  
Tetsuya Morizono ◽  
◽  
Yoji Yamada ◽  
Masatake Higashi ◽  
◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Real Time ◽  
Task Performance ◽  
User Satisfaction ◽  
Learning Algorithm ◽  
Impedance Control ◽  
Experimental Results ◽  
Multiple Goals ◽  
And Task

Controlling “feel” when operating a power-assist robot is important for improving robot operability, user satisfaction, and task performance efficiency. Autonomous adjustment of “feel” is considered with robots under impedance control, and reinforcement learning in adjustment when a task includes repetitive positioning is discussed. Experimental results demonstrate that an operational “feel” pattern appropriate for positioning at a goal is developed by adjustment. Adjustment assuming a single fixed goal is expanded to cases including multiple goals, in which it is assumed that one goal is chosen by a user in real time. To adjust operational “feel” to individual goals, an algorithm infers the goal. The same result as that for a single fixed goal is obtained in experiments, but experimental results suggest that design must be improved to where the accuracy of inference to the goal is taken into account by the adjustment learning algorithm.

Real-time PID control of a novel RCM mechanism designed and manufactured for use in laparoscopic surgery

2019 ◽  
Vol 47 (2) ◽  
pp. 153-166
Author(s):  
Serhat Aksungur ◽  
Muhammet Aydin ◽  
Oğuz Yakut
Keyword(s):  
Laparoscopic Surgery ◽  
Real Time ◽  
Pid Control ◽  
Position Control ◽  
Control Method ◽  
Operation Time ◽  
Position Error ◽  
Reference Points ◽  
Design Stage ◽  
Content Type

Purpose The purpose of this study is to design and manufacture a new remote center of motion (RCM) mechanism for use in laparoscopic surgical operations. In addition, obtaining the forward and inverse kinematic equations of the RCM mechanism and performing real-time position control with the Proportional–Integral–Derivative (PID) control method. Design/methodology/approach At the design stage, it is benefited from similar triangle rule. To obtain the kinematic equations in a simple way and facilitate control, two-fold displacement ratio is provided between the limbs where linear motion occurs. The rotation and displacement amounts required to move at the RCM point have been calculated by using the kinematic equations of the mechanism. Limb dimensions and motion limits are determined in the manner to avoid singularities and collisions. The x, y and z coordinates of the end effector have been defined as the reference point. Control of the mechanism was provided by PID control. To generate the user interface and control algorithm, MATLAB/Simulink real-time toolbox has been used. Four reference points were determined, control was performed and position error values were examined. MF634 Humusoft data acquisition card has been preferred to collect data from encoders. Findings A novel RCM mechanism has been designed and manufactured. Kinematic equations of this mechanism have been obtained. Position control of the cannula tip has been performed using PID control method for four different reference points. After settlement, maximum position error has been observed as 0.45 mm. Practical implications Structure of the designed mechanism is quite simple. Thus, costs are quite low. The operation area of the operator is widened by hanging the mechanism from the ceiling, so operational capability of health personnel is increasing. It helps to decrease the operation time and increase the success of the operation. Originality/value With this study, it is aimed to contribute to the literature by designing a new RCM mechanism. The rotation of the mechanism around the RCM point is provided by only one rotary motor, and the displacement of the RCM point in the vertical axis is provided by only one linear motor. The mechanism is also a surgical robot. The designed system is suitable for use in robot-assisted laparoscopic surgery in terms of maneuverability.

scholarly journals Optimal Fuzzy Impedance Control for a Robot Gripper Using Gradient Descent Iterative Learning Control in Fuzzy Rule Base Design

2020 ◽  
Vol 10 (11) ◽  
pp. 3821 ◽  
Author(s):  
Ba-Phuc Huynh ◽  
Yong-Lin Kuo
Keyword(s):  
Real Time ◽  
Iterative Learning Control ◽  
Control Method ◽  
Impedance Control ◽  
Learning Control ◽  
Iterative Learning ◽  
Rule Base ◽  
Control Approach ◽  
Robot Gripper ◽  
Gripping Force

This paper proposes a novel control approach for a robot gripper in which the impedance control, fuzzy logic control, and iterative learning control are combined in the same control schema. The impedance control is used to keep the gripping force at the desired value. The fuzzy impedance controller is designed to estimate the best impedance parameters in real time when gripping unknown objects. The iterative learning control process is employed to optimize the sample dataset for designing the rule base to enhance the effectiveness of the fuzzy impedance controller. Besides, the real-time gripping force estimator is designed to keep an unknown object from sliding down when picking it up. The simulation and experiment are implemented to verify the proposed method. The comparison with another control method is also made by repeating the experiments under equivalent conditions. The results show the feasibility and superiority of the proposed method.

Autonomous motion of a mobile manipulator using a combined torque and velocity control

Robotica ◽  
2004 ◽  
Vol 22 (6) ◽  
pp. 623-632 ◽  
Author(s):  
Damir Omrčen ◽  
Leon Žlajpah ◽  
Bojan Nemec
Keyword(s):  
Real Time ◽  
Motion Control ◽  
Obstacle Avoidance ◽  
Control Method ◽  
Mobile Platform ◽  
Mobile Manipulator ◽  
Velocity Control ◽  
Unstructured Environments ◽  
Time Motion ◽  
Fixed Base

The paper presents an algorithm for real-time motion control of a mobile manipulator in unstructured environments. The mobile manipulator consists of a velocity controlled mobile platform and a torque controlled manipulator. Therefore, a combination of torque and velocity control is used. For the obstacle avoidance two different principles are used: virtual repulsive velocity and action-reaction principle. The proposed control method has been verified on real system, composed of a mobile platform and a four DOFs manipulator arms. The results have been compared to the manipulator with a fixed base.

scholarly journals Design and control of a diagnosis and treatment aimed robotic platform for wrist and forearm rehabilitation: DIAGNOBOT

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774970 ◽  
Author(s):  
Mehmet Emin Aktan ◽  
Erhan Akdoğan
Keyword(s):  
Position Control ◽  
Control Method ◽  
Force Measurement ◽  
Impedance Control ◽  
Diagnosis And Treatment ◽  
Measurement Unit ◽  
Robotic Platform ◽  
Therapeutic Exercises ◽  
Flexion Extension ◽  
And Control

Therapeutic exercises play an important role in physical therapy and rehabilitation. The use of robots has been increasing day by day in the practice of therapeutic exercises. This study aims to design and control a novel robotic platform named DIAGNOBOT for diagnosis and treatment (therapeutic exercise). It has three 1-degree-of-freedom robotic manipulators and a single grasping force measurement unit. It is able to perform flexion–extension and ulnar–radial deviation movements for the wrist and pronation–supination movement for the forearm. The platform has a modular and compact structure and is capable of treating two patients concurrently. In order to control the DIAGNOBOT, an impedance control–based controller was developed for force control, which was required for the exercises, as well as a proportional–integral–derivative controller for position control. To model the resistive exercise, an angle-dependent impedance control method different from traditional methods has been proposed. Experiments were made on five healthy subjects and it has been demonstrated that the proposed robotic platform and its controller can perform therapeutic exercises.

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