Cartesian Impedance Control for Space Robotic Arm Based on End Force/Torque Sensor

2012 ◽  
Vol 268-270 ◽  
pp. 1531-1537
Author(s):  
Xiao Xing Dong ◽  
Ge Li ◽  
Geng Feng Liu ◽  
Jie Zhao
Keyword(s):  
Force Feedback ◽  
Impedance Control ◽  
Dynamic Properties ◽  
Contact Forces ◽  
Robotic Arm ◽  
Torque Sensor ◽  
Redundant Manipulator ◽  
Control Effect ◽  
Impedance Parameters ◽  
Kinematic Solution

A Cartesian impedance control for a 7-DOF space robotic arm (SRA) based on the feedback from a 6-dimensional force/torque sensor on its end effecter is presented in this paper. The unavoidable position error of SRA would generate large contact forces during the connection between SRA’s end effecter (EE) and grapple fixture (GF). To control the contact force we used 6D force feedback to modify the desired trajectory controlling a PID position inner loop to make the manipulator exert desired impedance dynamic properties on its end-effecter. After optimization of impedance parameters in Simulink, this control strategy has significantly improved the force control effect in EE/GF connection experiment. Kinematic solution of the 7-DOF redundant manipulator is also provided.

Force Control of a Robot Arm During Contact Task

2002 ◽  
Author(s):  
A. Yetik ◽  
V. Karadag
Keyword(s):  
Force Control ◽  
Control Algorithm ◽  
Force Feedback ◽  
Impedance Control ◽  
Mechanical Impedance ◽  
Contact Forces ◽  
Working Environment ◽  
Robot Arm ◽  
Simulation Results ◽  
End Effectors

There are extremely important applications to investigate the control of contact between the end-effectors and the object. During controlling an object, static or in motion, the robot arm should not be damaged. Forces are important in such conditions. The forces between the end-effectors and the object have to be controlled. The motion of the robot arm changes forces. Thats why, to control forces, a force kontrol algorithm must be developed. Previous conventional force control algorithms could not control the robot effectively by only considering the variation of working environment. In this study, a control algorithm strategy to achieve the desired interactions forces between the robot end-effector and the environment during contact tasks, has been developed. The surface of the object and robot are very stiff, thus contact spring coefficient Kc is very large, because of this Kc effect, the results of the forces simulation results, but we get suitable results. Study include, modelling robot arm, evaluating measured forces during contact and constructing a suitable force control algorithm, dynamics, kinematics and simulation results. In this study, we used impedans control which the surface of the object is very stiff, as known as impedance control does not try to track position and force trajectories directly, but rather to regulate the dynamic relationship between the contact forces and manipulator positions, namely the mechanical impedance. Impedance control focused on the design of a robot’s dynamic behavior as seen from the environment. In this control strategy, no hardware or software, switch is needed in the robot’s control system when the robot travels from the free motion space to the constrained space. The force feedback loop closes naturally as soon as the robot interacts with the environment, which changes the robot’s impedance as seen from the environment. By controlling the manipulator positions, and regulating their relationship to the contact forces, the manipulator can be controlled to maintain appropriate contact forces.

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.

scholarly journals Design and Impedance Control of a Traveling Wave Ultrasonic Motor with a Spherical Rotor

2019 ◽  
Vol 9 (23) ◽  
pp. 5083
Author(s):  
Yu Guo ◽  
Aiguo Song ◽  
Zhijun Sun
Keyword(s):  
Phase Difference ◽  
Traveling Wave ◽  
Force Feedback ◽  
Control Method ◽  
Impedance Control ◽  
Direct Torque Control ◽  
Ultrasonic Motor ◽  
Torque Control ◽  
Haptic Interaction ◽  
Control Effect

A traveling wave ultrasonic motor (TWUM) with a spherical rotor was designed and fabricated for a haptic interface. The mechanical characteristics testbed was set up to test the performance of the motor under the modulation of frequency and phase difference, as well as for conducting haptic interaction, and the phase difference modulation based on certain frequency was adopted as the driving mode for the proposed motor. Due to the complexity and uncertainty of the contact mechanics of the stator and rotor, the direct torque control effect of the TWUM is not ideal for the force feedback. In this paper, the impedance control method was adopted to realize the force interaction based on positional proportional–integral–derivative (PID) control. The virtual linear spring and virtual wall experiments are conducted to verify the effect of the proposed method. Results show that the position-based impedance control method has a better effect than direct torque control for the haptic interaction based on an ultrasonic motor (USM).

Virtual Driving Simulator for Measuring Dynamic Properties of Human Arm Movements

2006 ◽  
Vol 18 (2) ◽  
pp. 177-185 ◽  
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.

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.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

scholarly journals Research and Implementation of an Automatic Reset Force of a Force Feedback Handle

2020 ◽  
Vol 316 ◽  
pp. 01003
Author(s):  
Xin An Qiu ◽  
Shi Jia Wang ◽  
Dong Tao Ma
Keyword(s):  
Force Feedback ◽  
High Accuracy ◽  
Damping Coefficient ◽  
Robotic Arm ◽  
Force Model ◽  
Stiffness Coefficient ◽  
Application Field ◽  
New Development

Take the force feedback handle applied to the teleoperation of space robotic arm as a requirement. In order to improve users’ experience, we studied the automatic reset force of the handle. This paper proposes a springdamping model and applies it to the torque output of the motor to achieve a good reset of the handle, which is a new development of the application field of the automatic reset force model of the force feedback device. The experiment shows that the automatic reset force model has high accuracy when the handle returns to zero. In addition, through dynamic and reasonable adjustment of the stiffness coefficient and damping coefficient, it can meet the needs of different users for the automatic reset force of the force feedback handle.

scholarly journals Realization of Force Detection and Feedback Control for Slave Manipulator of Master/Slave Surgical Robot

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7489
Author(s):  
Hu Shi ◽  
Boyang Zhang ◽  
Xuesong Mei ◽  
Qichun Song
Keyword(s):  
Feedback Control ◽  
Force Feedback ◽  
Impedance Control ◽  
Three Dimensional ◽  
Surgical Instruments ◽  
Force Output ◽  
Software Environment ◽  
Force Detection ◽  
Academic Field ◽  
Learning Machine

Robot-assisted minimally invasive surgery (MIS) has received increasing attention, both in the academic field and clinical operation. Master/slave control is the most widely adopted manipulation mode for surgical robots. Thus, sensing the force of the surgical instruments located at the end of the slave manipulator through the main manipulator is critical to the operation. This study mainly addressed the force detection of the surgical instrument and force feedback control of the serial surgical robotic arm. A measurement device was developed to record the tool end force from the slave manipulator. An elastic element with an orthogonal beam structure was designed to sense the strain induced by force interactions. The relationship between the acting force and the output voltage was obtained through experiment, and the three-dimensional force output was decomposed using an extreme learning machine algorithm while considering the nonlinearity. The control of the force from the slave manipulator end was achieved. An impedance control strategy was adopted to restrict the force interaction amplitude. Modeling, simulation, and experimental verification were completed on the serial robotic manipulator platform along with virtual control in the MATLAB/Simulink software environment. The experimental results show that the measured force from the slave manipulator can provide feedback for impedance control with a delay of 0.15 s.

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