Development of Mechanical-Impedance-Varying Mechanism in Admittance Control

There have been numerous studies on the physical human-robot cooperative task system with impedance/admittance control in robot motion control. However, the problem of stability persists, wherein the control system becomes unstable when the robot comes into contact with a highly stiff environment. A variable impedance control strategy was proposed to circumvent this stability problem. However, a number of studies on variable impedance control are based on the variation of a parameter in the robot motion control software, and a mechanical variable impedance control has not been proposed. The purpose of this research is to propose a mechanical variable impedance control strategy using a mechanical device based on the lever principle. The proposed mechanism can adjust the magnitude of the input force to the force sensor by changing the position of application of the operating force on the beam. Adjusting the magnitude of the input force to the force sensor is equivalent to varying the impedance parameters of the robot; therefore, it is feasible to achieve mechanical variable impedance control using the proposed mechanism. In this study, the gain adjustment characteristics of the proposed mechanism were evaluated. The experimental results demonstrated that the operator can vary the impedance parameters of the robot by mechanically adjusting the input force to the force sensor and operating the robot using the proposed mechanism.

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Improving robotic impedance control performance employing a cascaded controller based on virtual dynamics model

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211023537 ◽

2022 ◽

pp. 095440622110235

Author(s):

Guanghui Liu ◽

Bing Han

Keyword(s):

Control Method ◽

Robot Manipulator ◽

Impedance Control ◽

Industrial Robot ◽

Mechanical Impedance ◽

Superior Performance ◽

Admittance Control ◽

Dynamics Model ◽

External Loop ◽

Virtual Impedance

We propose a cascaded impedance control algorithm based on a virtual dynamics model (VDM) to achieve robust and effective mechanical impedance for a robot interacting with unknown environments. This cascaded controller consists of an internal loop of virtual impedance control based on a VDM and an external loop of impedance reference control. The VDM-based virtual impedance control can achieve the same effect as the conventional admittance control; its intermediate output of force/torque serves as the input for the external loop reference impedance control. Therefore, this cascaded controller shows superior performance by combining the advantages of admittance control and impedance control. We evaluate the controller in multiple-contact experiments on a six-degrees of freedom (6-DOF) industrial robot manipulator. The result shows that under various contact situations such as soft and rigid surfaces and free space, the proposed method can rapidly track the target and effectively maintain stability. In the experiments conducted on the robot in contact with various environments, the proposed control method reduced the steady-state error by more than 20% compared with the conventional admittance control.

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Novel force-sensor-less contact motion control for quick and smooth industrial robot motion

IECON 2011 - 37th Annual Conference of the IEEE Industrial Electronics Society ◽

10.1109/iecon.2011.6120004 ◽

2011 ◽

Cited By ~ 6

Author(s):

Naoki Shimada ◽

Takashi Yoshioka ◽

Kiyoshi Ohishi ◽

Toshimasa Miyazaki

Keyword(s):

Motion Control ◽

Industrial Robot ◽

Force Sensor ◽

Robot Motion

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Research on a Denoising Method of the Force Sensor Signal Based on Multiple Filter

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.727-728.620 ◽

2015 ◽

Vol 727-728 ◽

pp. 620-625

Author(s):

Xiao Jian Wu ◽

Guo Kun Zuo ◽

Zhong Zhu Yang ◽

Shang Qing Xiao

Keyword(s):

Motion Control ◽

Digital Filtering ◽

Force Sensor ◽

Robot Motion ◽

Rehabilitation Robot ◽

Denoising Method ◽

Filtering Algorithm ◽

First Order ◽

Advantages And Disadvantages ◽

The Common

Forcesensor is very important in the rehabilitation robot. However, the force sensorsignals will introduce noise easily on the process of transmitting, amplifyingand sampling, which is very unfavorable for the robot motion control. Thispaper reviews the common digital filtering algorithm and analyzes theirprinciples, advantages and disadvantages, then designs an improved filteringalgorithm combines the limiting filtering algorithm withthe first-order lag filtering algorithm. At last, this paper verifies thefiltering effect by theoretical analysis, simulation and experiments.

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Virtual Driving Simulator for Measuring Dynamic Properties of Human Arm Movements

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2006.p0177 ◽

2006 ◽

Vol 18 (2) ◽

pp. 177-185 ◽

Cited By ~ 2

Author(s):

Yoshiyuki Tanaka ◽

◽

Ryoma Kanda ◽

Naoki Yamada ◽

Hitoshi Fukuba ◽

...

Keyword(s):

Driving Simulator ◽

Impedance Control ◽

Dynamic Properties ◽

Mechanical Impedance ◽

Rotational Axis ◽

Human Movements ◽

Human Arm ◽

Robotic Devices ◽

Impedance Parameters ◽

Machine Systems

This paper presents a virtual driving simulator using robotic devices as an example of human-machine systems to investigate dynamic properties of human movements in the operation of drive interfaces, such as steering wheels and transmission shifters. The simulator has virtual steering and transmission systems under variable impedance control, providing the operators with realistic operational response. Mechanical impedance parameters around the steering rotational axis were measured to demonstrate the effectiveness of the developed simulator.

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Motion Control of Mobile Robot Based on Immune Clonal Algorithm Evolved by Virus

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.143-144.269 ◽

2011 ◽

Vol 143-144 ◽

pp. 269-273

Author(s):

Yi Shen ◽

Qi Wang ◽

Zhao Li Ye ◽

Juan Chen ◽

Ming Xin Yuan

Keyword(s):

Virus Infection ◽

Local Search ◽

Mobile Robot ◽

Motion Control ◽

Control Strategy ◽

Pid Control ◽

Population Diversity ◽

Robot Motion ◽

Control Precision ◽

Simulation Results

To solve the motion control of mobile robot, a PID control optimized by improved immune clonal algorithm is presented. On the basis of immune clonal algorithm, a new virus evolutionary clonal algorithm (VECA) is provided firstly. The VECA focuses on the virus infection of population after immune mutation, which improves the population diversity and strengths the local search ability of immune clonal algorithm. Then the proposed VECA is used to optimize the algorithm parameters of PID control strategy for the robot motion. The simulation results show that VECA can realize the optimization of PID parameters and improve the control precision of path track.

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