Development of User-friendly Tuning for Impedance Control Parameters

2001 ◽  
Vol 13 (3) ◽  
pp. 230-237
Author(s):  
Junji shimamura ◽  
◽  
Masaki Arao ◽  
Keyword(s):  
Control System ◽  
Force Control ◽  
Impedance Control ◽  
External Environment ◽  
Parameter Tuning ◽  
Control Parameters ◽  
Trial And Error ◽  
Impedance Parameters ◽  
User Friendly ◽  
Ic Test

Impedance control, a type of indirect force control, is a method for providing a control system with compliance against forces effected by external environment. This method is expected to be applied primarily to industrial purposes, but it has such disadvantages that the process for tuning its parameters is based on a trial-and-error rule and largely depends on the controlling skill of operators. This paper describes a parameter tuning tool capable of readily setting the optimum impedance parameters and then clarifies the effectiveness of the suggested tool according to the results of experiments conducted on IC test inserter. Operators are not necessarily required to acquire the knowledge about impedance control.

scholarly journals Adaptive Variable Parameter Impedance Control for Apple Harvesting Robot Compliant Picking

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Ji Wei ◽  
Ding Yi ◽  
Xu Bo ◽  
Chen Guangyu ◽  
Zhao Dean
Keyword(s):  
Control System ◽  
Contact Force ◽  
Control Method ◽  
Impedance Control ◽  
Viscoelastic Model ◽  
Variable Parameter ◽  
Response Speed ◽  
Self Tuning ◽  
Impedance Parameters ◽  
Harvesting Robot

In order to reduce the damage of apple harvesting robot to fruits and achieve compliant picking, an adaptive variable parameter impedance control method for apple harvesting robot compliant picking is proposed in this paper. Firstly, the Burgers viscoelastic model is used to characterize the rheological properties of apples and study the variation of mechanical properties of apple grasping at different speeds. Then, a force-based impedance control system is designed. On this basis, aiming at the influence of impedance controller parameters on contact force, three impedance parameters self-tuning functions are constructed to complete the design of an improved force-based impedance control system based on the hyperbolic secant function. The simulation and experimental results show that the proposed control makes the desired force smoother, and its overshoot is about 2.3%. The response speed is faster, and the adjustment time of contact force is shorter of about 0.48 s. The contact force overshoot is about 2%, which is 37.5% less than that of the traditional force-based impedance control. This research improves the control performance for apple harvesting robot compliant picking.

INFINITE DIMENSION MODELING OF A NOVEL MICROFORCE SENSOR AND THE APPLICATION IN MICROMANIPULATION

2010 ◽  
Vol 07 (04) ◽  
pp. 299-307
Author(s):  
YIYANG LIU ◽  
YUECHAO WANG ◽  
PENG YU ◽  
ZAILI DONG
Keyword(s):  
Surface Tension ◽  
Control System ◽  
Force Control ◽  
Impedance Control ◽  
Infinite Dimension

To accurately measure the micro-interactive force (for example, adhesion, surface tension, friction, and assembly force) acting on microdevices during micro/nano manipulation, a novel microforce sensor that can reliably measure force in the range of sub-micro-Newton (μN) is designed and developed in this study. During the application of this microforce sensor in micro/nano manipulation, the accuracy of this sensor's model is quite important to the force control of the system. Therefore, the accurate infinite dimension model of the microforce sensor and micromanipulator is built up. Based on the infinite dimension model, the impedance control system is designed. To verify the infinite dimension model and the control system, micromanipulation experiments are designed and realized. Experiment results verify the accuracy of the infinite dimension model of the sensor and show the efficiency of the impedance control system. The developed microforce sensor and the infinite dimension modeling provide a feasible and versatile solution in microforce sensing and feedback force control for micro/nano manipulation, and will promote the technology of automating the micro/nano manipulation.

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.

scholarly journals Design of a User-Friendly Control System using Least Control Parameters

2014 ◽  
Vol 9 (1) ◽  
pp. 67-77
Author(s):  
Youngjin Heo ◽  
Daegil Park ◽  
Jinhyun Kim
Keyword(s):  
Control System ◽  
Control Parameters ◽  
User Friendly

Constant-Value Control of Joystick Operating Force Using Acoustic System Having Feedback Control System

2008 ◽  
Vol 20 (4) ◽  
pp. 578-584
Author(s):  
Taichi Sato ◽  
◽  
Yuta Murayama ◽  
Hiroshi Igarashi ◽  
◽  
...  
Keyword(s):  
Control System ◽  
Control Parameter ◽  
Control Experiment ◽  
Parameter Tuning ◽  
Test Subject ◽  
Control Parameters ◽  
Tuning Method ◽  
Acoustic Control ◽  
Tuning Methods ◽  
Time Waveform

We have conducted experiments of operating a force operating joystick to the sound. Test subjects listen to white noise with square envelope in a semi anechoic room and joystick operating force is measured. We have seen that time waveform of operating force varies among experiments. Variation in operating force depends on day, test subject, etc. And, we have established an acoustic control system that feedbacks operating force for realizing target value of joystick operating force. We conducted a constant-value control experiment using PI control in which each control parameters’ effects are studied. As a result, among three existing control parameter tuning methods, Cohen-Coon’s control parameter tuning method is the most appropriate for our system.

Special Issue on Force and Compliance Control

1991 ◽  
Vol 3 (6) ◽  
pp. 445-445
Author(s):  
Kazuo Tanie ◽  
Keyword(s):  
Force Control ◽  
Impedance Control ◽  
Editorial Staff ◽  
Control Technique ◽  
Special Issue ◽  
Constraint Forces ◽  
Compliance Control ◽  
Research Activities ◽  
Impedance Parameters ◽  
Control Forces

When robots perform tasks in which constraint forces are applied to the end effector from the environment, the interactive forces must be controlled. Considering this problem, in robotics, force control has been recognized as one of the most important research topics since the beginning of robotics research. In order to control forces dexterously, several studies have been conducted concerning sensors, actuators, and control algorithms. Currently, compliance and impedance control is a newly identified topic in force control. In the biological analysis of human behavior, it is well known that man adjusts the impedance of skeletal muscles according to the kind of task and can perform them dexterously. A compliance/impedance control technique has been proposed in order to realize such a function in robot motion. The feature of compliance/impedance control is control of the interacting forces not directly but through adjustment of compliance/impedance parameters of the system. This control structure provides several benefits to enable robots perform to complex tasks dexterously; however, there are still a lot of problems to be solved before it can be put to practical use. This Special Issue provides an overview of recent research activities concerning force control technology in robotics with an emphasis on compliance and impedance control. The papers compiled in this issue include various topics of force control, such as compliant motion control, biological aspects of compliance control and this force control using different kinds of actuators. I believe that the contents of this issue contains useful information for researchers and engineers with interests in this area. Finally, I would like to express my appreciation to the authors for their efforts and contributions to this issue and also to the members of the editorial staff for their skillful assistance.

Variable impedance control of finger exoskeleton for hand rehabilitation following stroke

2019 ◽  
Vol 47 (1) ◽  
pp. 23-32
Author(s):  
Fuhai Zhang ◽  
Legeng Lin ◽  
Lei Yang ◽  
Yili Fu
Keyword(s):  
Control System ◽  
Real Time ◽  
Control Method ◽  
Impedance Control ◽  
Contact Forces ◽  
Hand Rehabilitation ◽  
Content Type ◽  
Flexion Extension ◽  
Output Trajectory ◽  
Impedance Parameters

Purpose The purpose of this paper is to propose a variable impedance control method of finger exoskeleton for hand rehabilitation using the contact forces between the finger and the exoskeleton, making the output trajectory of finger exoskeleton comply with the natural flexion-extension (NFE) trajectory accurately and adaptively. Design/methodology/approach This paper presents a variable impedance control method based on fuzzy neural network (FNN). The impedance control system sets the contact forces and joint angles collected by sensors as input. Then it uses the offline-trained FNN system to acquire the impedance parameters in real time, thus realizing tracking the NFE trajectory. K-means clustering method is applied to construct FNN, which can obtain the number of fuzzy rules automatically. Findings The results of simulations and experiments both show that the finger exoskeleton has an accurate output trajectory and an adaptive performance on three subjects with different physiological parameters. The variable impedance control system can drive the finger exoskeleton to comply with the NFE trajectory accurately and adaptively using the continuously changing contact forces. Originality/value The finger is regarded as a part of the control system to get the contact forces between finger and exoskeleton, and the impedance parameters can be updated in real time to make the output trajectory comply with the NFE trajectory accurately and adaptively during the rehabilitation.

Effect of Inner and Outer Wheels Driving Force Control on Small Electric Vehicle

2020 ◽  
Vol 17 (4) ◽  
pp. 8246-8254
Author(s):  
K. Shibazaki ◽  
H. Nozaki
Keyword(s):  
Control System ◽  
Angular Velocity ◽  
Electric Vehicle ◽  
Force Constant ◽  
Force Control ◽  
Driving Force ◽  
Vehicle Control ◽  
Steering Angle ◽  
Force Control System ◽  
The Difference

In this study, in order to improve steering stability during turning, we devised an inner and outer wheel driving force control system that is based on the steering angle and steering angular velocity, and verified its effectiveness via running tests. In the driving force control system based on steering angle, the inner wheel driving force is weakened in proportion to the steering angle during a turn, and the difference in driving force is applied to the inner and outer wheels by strengthening the outer wheel driving force. In the driving force control (based on steering angular velocity), the value obtained by multiplying the driving force constant and the steering angular velocity,  that differentiates the driver steering input during turning output as the driving force of the inner and outer wheels. By controlling the driving force of the inner and outer wheels, it reduces the maximum steering angle by 40 deg and it became possible to improve the cornering marginal performance and improve the steering stability at the J-turn. In the pylon slalom it reduces the maximum steering angle by 45 deg and it became possible to improve the responsiveness of the vehicle. Control by steering angle is effective during steady turning, while control by steering angular velocity is effective during sharp turning. The inner and outer wheel driving force control are expected to further improve steering stability.

Combined Temperature and Force Control for Robotic Friction Stir Welding

2013 ◽  
Author(s):  
Axel Fehrenbacher ◽  
Christopher B. Smith ◽  
Neil A. Duffie ◽  
Nicola J. Ferrier ◽  
Frank E. Pfefferkorn ◽  
...  
Keyword(s):  
Control System ◽  
Force Control ◽  
Closed Loop ◽  
Interface Temperature ◽  
Closed Loop Control ◽  
Weld Quality ◽  
Loop Control ◽  
Friction Stir ◽  
Tool Position ◽  
Robotic Friction Stir Welding

The objective of this research is to develop a closed-loop control system for robotic friction stir welding (FSW) that simultaneously controls force and temperature in order to maintain weld quality under various process disturbances. FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. During FSW, several process parameter and condition variations (thermal constraints, material properties, geometry, etc.) are present. The FSW process can be sensitive to these variations, which are commonly present in a production environment; hence, there is a significant need to control the process to assure high weld quality. Reliable FSW for a wide range of applications will require closed-loop control of certain process parameters. A linear multi-input-multi-output process model has been developed that captures the dynamic relations between two process inputs (commanded spindle speed and commanded vertical tool position) and two process outputs (interface temperature and axial force). A closed-loop controller was implemented that combines temperature and force control on an industrial robotic FSW system. The performance of the combined control system was demonstrated with successful command tracking and disturbance rejection. Within a certain range, desired axial forces and interface temperatures are achieved by automatically adjusting the spindle speed and the vertical tool position at the same time. The axial force and interface temperature is maintained during both thermal and geometric disturbances and thus weld quality can be maintained for a variety of conditions in which each control strategy applied independently could fail.

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