scholarly journals Hybrid Force and Position Control Strategy of Robonaut Performing Object Transfer Task

2018 ◽  
Vol 160 ◽  
pp. 05003
Author(s):  
Gang Chen ◽  
Yu-Qi Wang ◽  
Qing-Xuan Jia ◽  
Pei-Lin Cai
Keyword(s):  
Control Strategy ◽  
Position Control ◽  
Control Method ◽  
Transfer Task ◽  
Internal Force ◽  
Matlab Simulation ◽  
Constraint Force ◽  
Common Control ◽  
Transfer Operation ◽  
External Forces

This paper proposes a coordinated hybrid force/position control strategy of robonaut performing object transfer operation. Firstly, the constraint relationships between robonaut and object are presented. Base on them, the unified dynamic model of the robonaut and object is established to design the hybrid force/position control method. The movement, the internal force and the external constraint force of the object are considered as the control targets of the control system. Finally, a MATLAB simulation of the robonaut performing object transfer task verifies the correctness and effectiveness of the proposed method. The results show that all the targets can be control accurately by using the method proposed in this paper. The presented control method can control both internal and external forces while maintaining control accuracy, which is a common control strategy.

Time-Optimal Coordination Control for the Gear-Shifting Process in Electric-Driven Mechanical Transmission (Dog Clutch) without Impacts

2020 ◽  
Vol 9 (2) ◽  
pp. 155-168
Author(s):  
Ziwang Lu ◽  
◽  
Guangyu Tian ◽  
Keyword(s):  
Control Strategy ◽  
Position Control ◽  
Control Method ◽  
Synchronization Control ◽  
Mechanical Transmission ◽  
Coordination Control ◽  
Optimal Position ◽  
Drive Motor ◽  
Time Optimal ◽  
Optimal Coordination

Torque interruption and shift jerk are the two main issues that occur during the gear-shifting process of electric-driven mechanical transmission. Herein, a time-optimal coordination control strategy between the the drive motor and the shift motor is proposed to eliminate the impacts between the sleeve and the gear ring. To determine the optimal control law, first, a gear-shifting dynamic model is constructed to capture the drive motor and shift motor dynamics. Next, the time-optimal dual synchronization control for the drive motor and the time-optimal position control for the shift motor are designed. Moreover, a switched control for the shift motor between a bang-off-bang control and a receding horizon control (RHC) law is derived to match the time-optimal dual synchronization control strategy of the drive motor. Finally, two case studies are conducted to validate the bang-off-bang control and RHC. In addition, the method to obtain the appropriate parameters of the drive motor and shift motor is analyzed according to the coordination control method.

scholarly journals Position Control of Cable-Driven Robotic Soft Arm Based on Deep Reinforcement Learning

Information ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 310
Author(s):  
Qiuxuan Wu ◽  
Yueqin Gu ◽  
Yancheng Li ◽  
Botao Zhang ◽  
Sergey A. Chepinskiy ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Control Strategy ◽  
Position Control ◽  
Control Method ◽  
Strategy Training ◽  
Soft Robot ◽  
Robot Arm ◽  
Control Task ◽  
Modeling And Control ◽  
And Migration

The cable-driven soft arm is mostly made of soft material; it is difficult to control because of the material characteristics, so the traditional robot arm modeling and control methods cannot be directly applied to the soft robot arm. In this paper, we combine the data-driven modeling method with the reinforcement learning control method to realize the position control task of robotic soft arm, the method of control strategy based on deep Q learning. In order to solve slow convergence and unstable effect in the process of simulation and migration when deep reinforcement learning is applied to the actual robot control task, a control strategy learning method is designed, which is based on the experimental data, to establish a simulation environment for control strategy training, and then applied to the real environment. Finally, it is proved by experiment that the method can effectively complete the control of the soft robot arm, which has better robustness than the traditional method.

Transparency performance improvement for multi-master multi-slave teleoperation systems with external force estimation

2017 ◽  
Vol 40 (13) ◽  
pp. 3851-3859 ◽  
Author(s):  
Farhad Azimifar ◽  
Saman Ahmadkhosravi Rozi ◽  
Ahmad Saleh ◽  
Iman Afyouni
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Estimation Algorithm ◽  
Lyapunov Theory ◽  
Shared Environment ◽  
Force Estimation ◽  
Teleoperation System ◽  
Common Control ◽  
Control Scheme ◽  
External Forces

Cooperative teleoperation combines two traditional areas of robotics, that is, teleoperation and collaborative manipulation. Cooperative telerobotic systems consist of multiple pairs of master and slave robotic manipulators operating in a shared environment. The most common control frameworks for nonlinear systems, that is, Proportional Derivative (PD) controllers, possess considerable deficiency in contact motion. In this paper, a novel control scheme is proposed for a nonlinear bilateral cooperative teleoperation system with time delay. In addition to position and velocity signals, force signals are employed in the control strategy. This modification significantly enhances the poor transparency when the slave robots are in collision with the environment. To cope with external forces measurement, a modified force estimation algorithm is proposed to estimate human and environment forces. The closed loop stability of the nonlinear cooperative teleoperation system with the proposed control scheme is investigated using the Lyapunov theory. The main achievement of this research is the stability of the closed loop cooperative teleoperation system in the presence of estimated operator and environmental forces. In addition, it is theoretically and experimentally proved that force reflection occurs and transparency is improved at the same time. Experimental results demonstrate the efficiency of the presented control strategy in free motion as well as when the slave robots are in contact with the environment.

Compliance Control and Stability Analysis of Cooperating Robot manipulators

Robotica ◽  
1989 ◽  
Vol 7 (3) ◽  
pp. 191-198 ◽  
Author(s):  
H. Kazerooni
Keyword(s):  
Stability Analysis ◽  
Control Strategy ◽  
Position Control ◽  
Control Method ◽  
Robot Manipulators ◽  
Contact Point ◽  
Sensitivity Function ◽  
Compliance Control ◽  
Cooperating Robots ◽  
The Stability

SUMMARYThe work presented here is the description of the control strategy of two cooperating robots. A two–finger hand is an example of such a System. The control method allows for position control of the contact point by one of the robots while the other robot controls the contact force. The stability analysis of two robot manipulators has been investigated using unstructured models for dynamic behavior of robot manipulators. For the stability of two robots, there must be some initial compliance in either robot. The initial compliance in the robots can be obtained by a non-zero sensitivity function for the tracking controller or a passive compliant element such as an RCC.

scholarly journals Study on motion analysis and force/position hydraulic control of a parallel cylinder transmission system of heavy-duty quadruped robot

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141983155
Author(s):  
Junpeng Shao ◽  
Chaohui Jin ◽  
Xigui Wang ◽  
Yongmei Wang ◽  
Jing Jing ◽  
...  
Keyword(s):  
Control Strategy ◽  
Position Control ◽  
Internal Force ◽  
Quadruped Robot ◽  
Control Synthesis ◽  
Joint Control ◽  
Phase Lag ◽  
Heavy Duty ◽  
Transmission Scheme ◽  
Heavy Load

In the article, a heavy-duty quadruped robot was designed. A parallel cylinder transmission scheme for the heavy load torque of the hip joint of heavy-duty hydraulic quadruped robot is proposed, the mathematical model of the parallel cylinder system is derived, the model characteristics of the parallel cylinder system are analyzed, the characteristics of internal force and joint control of parallel cylinders are considered, the force/position hybrid control of parallel cylinder is proposed to eliminate the internal forces and realize the requirement of joint control and the force/position control is decoupled by the design of the force and position signal. According to the characteristics of the servo cylinder force control model, the flow compensation and speed compensation are introduced, the minimum control synthesis controller is used to control the servo cylinder force and the proportional integral controller is applied to control the position of servo cylinder. The compound control strategy is analyzed on the table of parallel cylinder, and the experimental results show that the amplitude attenuation and phase lag of position and force are less than 10% and 18°, respectively, and the efficiency of the proposed control strategy is verified. The research results of this article will be widely used in many fields of robot control in the future.

Application of Double Motor DC Drive in the Crane Control System

2013 ◽  
Vol 385-386 ◽  
pp. 886-889
Author(s):  
Shang Feng Guo ◽  
Hong Li
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Automatic Control System ◽  
Position Control ◽  
Control Method ◽  
Matlab Simulation ◽  
Crane Control ◽  
Maintenance Work ◽  
Dc Drive

Crane with its advantages is widely used in industrial and mining enterprises, but the old control system will bring a series of problems which increased the daily maintenance work. This article adopts the double machine automatic control system of dc drag, and position control method based on the standard stroke was designed, and its validity is verified by Matlab simulation.

scholarly journals Internal and External Forces Measurement of Planar 3-DOF Redundantly Actuated Parallel Mechanism by Axial Force Sensors

ISRN Robotics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Harada ◽  
Podi Liu
Keyword(s):  
Parallel Mechanism ◽  
Force Sensor ◽  
Internal Force ◽  
Time System ◽  
Constraint Force ◽  
Real Time System ◽  
Axial Forces ◽  
Redundantly Actuated ◽  
Internal Forces ◽  
External Forces

This paper proposes a method for measuring the internal and external forces of a planar 3-DOF (degree of freedom) redundantly actuated parallel mechanism. The internal forces, force acts inside the endplate and mechanism constraint force, and the external forces, forces act on the endplate and thrusts by actuators, were measured simultaneously using the axial forces of the rods. Kinetostatic equations of the parallel mechanism were used to derive algorithms for measuring the internal and external forces. A link axis force sensor was developed using a strain gauge sensor. To verify the actual internal force of the endplate, a force sensor was also installed on the endplate. A real-time system for measuring the forces of the parallel mechanism was developed using RT-Linux. The external and internal forces were measured accurately.

Development of a two-wheel mobile manipulator: balancing and interaction control

Robotica ◽  
2014 ◽  
Vol 32 (7) ◽  
pp. 1135-1152 ◽  
Author(s):  
Jae Kook Ahn ◽  
Seul Jung
Keyword(s):  
Force Control ◽  
Position Control ◽  
Control Method ◽  
Experimental Studies ◽  
Service Robot ◽  
Mobile Manipulator ◽  
Interaction Control ◽  
External Forces ◽  
And Control ◽  
Balancing Control

SUMMARYThis paper focuses on practical application of a mobile manipulator by presenting the development and control of a two-wheel mobile robot with two arms called a balancing service robot (BSR) designated for indoor services. The mobile manipulator requires not only robust balancing position control but also force control to interact with objects. Movements with two wheels are controlled to satisfy stable balancing control for navigation and manipulation with two arms to perform given tasks. The robot is required to deal with external forces to maintain balance. The position-based impedance force control method (the admittance control) is utilized by filtering the force with the impedance function to react to the applied force from the operator. Experimental studies of navigation control under balancing condition and interacting control with a human operator are demonstrated. Experimental results confirm that the robot has smooth reaction against the disturbance induced by the applied external force.

Posture adjustment method for large components of aircraft based on hybrid force-position control

2020 ◽  
Vol 47 (3) ◽  
pp. 381-393 ◽  
Author(s):  
Wenmin Chu ◽  
Xiang Huang
Keyword(s):  
Position Control ◽  
Control Method ◽  
Screw Theory ◽  
Interaction Force ◽  
Internal Force ◽  
Numerical Control ◽  
Content Type ◽  
Homogeneous Transformation Matrix ◽  
Adjustment System ◽  
Posture Adjustment

Purpose Flexible tooling for adjusting the posture of large components of aircraft (LCA) is composed of several numerical control locators (NCLs). Because of the manufacture and installation errors of NCL, the traditional control method of NCL may cause great interaction force between NCLs and form the internal force of LCA during the process of posture adjustment. Aiming at this problem, the purpose of this paper is to propose a control method for posture adjustment system based on hybrid force-position control (HFPC) to reduce the internal force of posture adjustment. Design/methodology/approach First of all, the causes of internal force of posture adjustment were analyzed by using homogeneous transformation matrix and inverse kinematics. Then, axles of NCLs were divided into position control axle and force control axle based on the screw theory, and the dynamic characteristics of each axle were simulated by MATLAB. Finally, a simulated posture adjustment system was built in the laboratory to carry out HFPC experiment and was compared with the other two traditional control methods for posture adjustment. Findings The experiment results show that HFPC method for redundant actuated parallel mechanism (RAPM) can significantly reduce the interaction force between NCLs. Originality/value In this paper, HFPC is applied to the control of the posture adjustment system, which reduces the internal force of LCA and improves the assembly quality of aircraft parts.

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