Impedance Control of Free-Flying Space Robot for Orbital Servicing

2006 ◽  
Vol 18 (5) ◽  
pp. 608-617 ◽  
Author(s):  
Hiroki Nakanishi ◽  
◽  
Kazuya Yoshida
Keyword(s):  
Control Method ◽  
Impedance Control ◽  
Space Robot ◽  
Space Manipulator ◽  
Inertial Space ◽  
Mass Damper ◽  
Fixed Base ◽  
Manipulator Arm ◽  
Spring System ◽  
Target Satellite

One of the most important phases of orbital servicing by a space robot is capturing a target satellite. In this phase, there is the risk that contact will push the target and robot away from each other. Controlling the impedance of the manipulator effectively prevents this. For a free-flying space robot, however, conventional methods used for fixed base robots cannot be used because the motion of the base interferes with the manipulator motion. An impedance control method for a space manipulator arm is proposed, where the end tip of the manipulator is controlled as if a mass-damper-spring system fixed in inertial space. Possible applications in orbital servicing are also discussed.

Patient-Robot-Therapist Collaboration Using Resistive Impedance Controlled Tele-Robotic Systems Subjected to Time Delays

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Mojtaba Sharifi ◽  
Hassan Salarieh ◽  
Saeed Behzadipour ◽  
Mahdi Tavakoli
Keyword(s):  
Time Delays ◽  
Control Method ◽  
Impedance Control ◽  
Robotic Systems ◽  
Virtual Mass ◽  
Healthy Human ◽  
Impedance Model ◽  
Modeling Uncertainties ◽  
Mass Damper ◽  
Spring System

In this paper, an approach to physical collaboration between a patient and a therapist is proposed using a bilateral impedance control strategy developed for delayed tele-robotic systems. The patient performs a tele-rehabilitation task in a resistive virtual environment with the help of online assistive forces from the therapist being provided through teleoperation. Using this strategy, the patient's involuntary hand tremors can be filtered out and the effort of severely impaired patients can be amplified in order to facilitate their early engagement in physical tasks. The response of the first desired impedance model is tracked by the master robot (interacting with the patient), and the master trajectory plus a deviation as the response of the second impedance model is tracked by the slave robot (interacting with the therapist). Note that the first impedance model is a virtual mass-damper-spring system that has a response trajectory to the combination of patient and therapist forces. Similarly, the second impedance model is a virtual mass-damper-spring system that generates the desired slave–master deviation trajectory as its response to the therapist force. Transmitted signals through the communication channels are subjected to time delays, which exist in home-based rehabilitation (i.e., tele-rehabilitation). Tracking of the impedance models responses in the presence of modeling uncertainties is achieved by employing a nonlinear bilateral adaptive controller and proven using a Lyapunov analysis. The stability of delayed teleoperation system is also proven using the absolute stability criterion. The proposed control method is experimentally evaluated for patient–therapist collaboration in resistive/assistive tasks. In these experiments, a healthy human operator simulates a poststroke patient behavior during the interaction with the master robot.

Research on the Space Manipulator Control in Capturing Object Based on Noncontact Impedance Control

2012 ◽  
Vol 546-547 ◽  
pp. 1014-1019 ◽  
Author(s):  
Zhi Gang Chen ◽  
Cui Ru Wu ◽  
Guang Yu Zhang
Keyword(s):  
Control Method ◽  
Impedance Control ◽  
Joint Space ◽  
Space Manipulator ◽  
Object Based ◽  
Space Manipulators ◽  
Impedance Parameters ◽  
The Impact ◽  
Virtual Impedance ◽  
Manipulator Control

This paper discusses the control of free flying space manipulators in the impact process which happens in the capturing operation. To solve the intense coupling of the kinematics and dynamics between the space manipulator and the base, this paper builds the noncontact impedance control model of the 6-joint space manipulator system, which can control the space manipulator before impacting with the objects. Computer simulations are performed to verify that the noncontact impedance control method can make the end-effector of the space manipulator keep desired dynamic characteristics and the adjustment of virtual impedance parameters can control the impact force value efficiently.

scholarly journals Research on Control Strategy of Manipulator Based on Simulation

2021 ◽  
Vol 2093 (1) ◽  
pp. 012007
Author(s):  
JiaLei Su
Keyword(s):  
Control Method ◽  
Impedance Control ◽  
Rapid Development ◽  
Space Robot ◽  
Space Environment ◽  
Robotic Arm ◽  
Control Element ◽  
Feedback Signal ◽  
Robot Arm ◽  
Control Effect

Abstract The force supple control method of robotic arm has been widely researched internationally for many years, and its specific use varies according to the structure of the robotic arm, the location of the sensor, the working space environment, and other factors. Based on the force control principle and control method of the space robot arm, this paper adopts the position-based Cartesian spatial impedance control and proposes an effective forcesmoothing control method after pre-processing the feedback signal of the six-dimensional force sensor installed at the end of the space robot arm with the coordinate system conversion. In addition, the proposed position-based Cartesian spatial impedance control method is modeled and simulated to analyze the effect of each control element on the force-following control effect, to find out the control conditions that can optimize the force-position control effect, and finally to optimize the impedance parameters. This study aims to promote the rapid development of the field of robotic arm control.

Ground verification of space robot capturing the free-floating target based on visual servoing control with time delay

2014 ◽  
Vol 41 (6) ◽  
pp. 543-556 ◽  
Author(s):  
Haitao Yang ◽  
Minghe Jin ◽  
Zongwu Xie ◽  
Kui Sun ◽  
Hong Liu
Keyword(s):  
Time Delay ◽  
Motion Planning ◽  
Visual Servoing ◽  
Space Robot ◽  
Hardware In The Loop ◽  
Space Manipulator ◽  
Content Type ◽  
Operating Space ◽  
Base Disturbance ◽  
Target Satellite

Purpose – The purpose of this paper is to solve the ground verification and test method for space robot system capturing the target satellite based on visual servoing with time-delay in 3-dimensional space prior to space robot being launched. Design/methodology/approach – To implement the approaching and capturing task, a motion planning method for visual servoing the space manipulator to capture a moving target is presented. This is mainly used to solve the time-delay problem of the visual servoing control system and the motion uncertainty of the target satellite. To verify and test the feasibility and reliability of the method in three-dimensional (3D) operating space, a set of ground hardware-in-the-loop simulation verification systems is developed, which adopts the end-tip kinematics equivalence and dynamics simulation method. Findings – The results of the ground hardware-in-the-loop simulation experiment validate the reliability of the eye-in-hand visual system in the 3D operating space and prove the validity of the visual servoing motion planning method with time-delay compensation. At the same time, owing to the dynamics simulator of the space robot added in the ground hardware-in-the-loop verification system, the base disturbance can be considered during the approaching and capturing procedure, which makes the ground verification system realistic and credible. Originality/value – The ground verification experiment system includes the real controller of space manipulator, the eye-in-hand camera and the dynamics simulator, which can veritably simulate the capturing process based on the visual servoing in space and consider the effect of time delay and the free-floating base disturbance.

Hand-eye servo and impedance control for manipulator arm to capture target satellite safely

Robotica ◽  
2014 ◽  
Vol 33 (4) ◽  
pp. 848-864 ◽  
Author(s):  
Gan Ma ◽  
Zhihong Jiang ◽  
Hui Li ◽  
Junyao Gao ◽  
Zhangguo Yu ◽  
...  
Keyword(s):  
Impedance Control ◽  
Experimental System ◽  
Control Law ◽  
Planning Strategy ◽  
Target Field ◽  
Manipulator Arm ◽  
Servo Controller ◽  
Best Fit ◽  
Target Satellite ◽  
Field Robot

SUMMARYA crucial problem is the risk that a manipulator arm would be damaged by twisting or bending during and after contacting a target satellite. This paper presents a solution to minimize the risk of damage to the arm and thereby enhance contact performance. First, a hand-eye servo controller is proposed as a method for accurately tracking and capturing a target satellite. Next, a motion planning strategy is employed to obtain the best-fit contacting moments. Also, an impedance control law is implemented to increase protection during operation and to ensure more accurate compliance. Finally, to overcome the challenge of verifying algorithms for a space manipulator while on the ground, a novel experimental system with a 6-DOF (degree of freedom) manipulator on a chaser field robot is presented and implemented to capture a target field robot; the proposed methods are then validated using the experimental platform.

Disturbance Compensation Control of a Free-Flying Robot

1994 ◽  
Vol 6 (5) ◽  
pp. 360-369
Author(s):  
Hirohiko Arai ◽  
◽  
Kazuo Tanie
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Reaction Force ◽  
Space Robot ◽  
Joint Torque ◽  
Coordinate Frame ◽  
Disturbance Compensation ◽  
Compensation Control ◽  
Fixed Base ◽  
Unknown Disturbances

Disturbance compensation control of a free-flying space robot is considered in this paper. In the method proposed here, disturbances imposed on a nominal dynamic model are estimated and compensated by utilizing a combination of joint torque input and acceleration signals. The dynamics of the equivalent manipulator with a fixed base is treated as the nominal model, noting that the mass of the base satellite is usually much larger than that of the manipulator. The attitude of the base satellite changes because of the reaction force generated by the manipulator. However, the influence of the change is estimated and compensated as a disturbance based on a combination of the joint torque and the acceleration of the end-effector in the operational coordinate frame. Computation of the proposed control method is as simple as the control of a manipulator with a fixed base. The proposed method is robust against unknown disturbances and modeling errors. This method can also be extended to the case of a space robot with multiple manipulators and attitude control of the base satellite. The effectiveness of the method is demonstrated by computer simulations.

Impedance Control Based Sliding Mode for Lower Limb Rehabilitation Robot

2014 ◽  
Vol 672-674 ◽  
pp. 1770-1773 ◽  
Author(s):  
Fu Cheng Cao ◽  
Li Min Du
Keyword(s):  
Dynamic Response ◽  
Sliding Mode Control ◽  
Lower Limb ◽  
Control Method ◽  
Sliding Mode ◽  
Impedance Control ◽  
Rehabilitation Robot ◽  
Active Rehabilitation ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

Aimed at improving the dynamic response of the lower limb for patients, an impedance control method based on sliding mode was presented to implement an active rehabilitation. Impedance control can achieve a target-reaching training without the help of a therapist and sliding mode control has a robustness to system uncertainty and vary limb strength. Simulations demonstrate the efficacy of the proposed method for lower limb rehabilitation.

A novel tuned mass-conical spring system for passive vibration control of a variable mass structure

2021 ◽  
pp. 107754632110004
Author(s):  
Sanjukta Chakraborty ◽  
Aparna (Dey) Ghosh ◽  
Samit Ray-Chaudhuri
Keyword(s):  
Variable Mass ◽  
Design Procedure ◽  
Time History ◽  
Tuned Mass Damper ◽  
Water Tank ◽  
Mass System ◽  
Mass Damper ◽  
Linear Spring ◽  
Spring System ◽  
Elevated Water

This article presents the design of a tuned mass damper with a conical spring to enable tuning to the natural frequency of the system at multiple values, as may be convenient in case of a system with fluctuations in the mass. The principle and design procedure of the conical spring in the context of a varying mass system are presented. A passive feedback control mechanism based on a simple pulley-mass system is devised to cater to the multi-tuning requirements. A design example of an elevated water tank with fluctuating water content, subjected to ground excitation, is considered to numerically illustrate the efficiency of such a tuned mass damper associated with the conical spring. The conical spring is designed based on the tuning requirements at different mass conditions of the elevated water tank by satisfying the allowable load bearing capacity of the spring. Comparisons are made with the conventional passive tuned mass damper with a linear spring tuned to the full tank condition. Results from time history analysis reveal that the conical spring-tuned mass damper can be successfully designed to remain tuned and thereby achieve significant response reductions under stiffening conditions of the primary structure, whereas the linear spring-tuned mass damper suffers performance degradation because of detuning, whenever there is any fluctuation in the system mass.

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