Cartesian Space Synchronous Impedance Control of Two 7-DOF robot arm manipulators

2014 ◽  
Author(s):  
Minghe Jin ◽  
Zijian Zhang ◽  
Fenglei Ni ◽  
Hong Liu
Keyword(s):  
Impedance Control ◽  
Robot Arm ◽  
Cartesian Space

Learning peg-in-hole assembly using Cartesian DMPs with feedback mechanism

2020 ◽  
Vol 40 (6) ◽  
pp. 895-904
Author(s):  
Nailong Liu ◽  
Xiaodong Zhou ◽  
Zhaoming Liu ◽  
Hongwei Wang ◽  
Long Cui
Keyword(s):  
Force Feedback ◽  
Impedance Control ◽  
Dynamic Performance ◽  
Feedback Mechanism ◽  
Learning From Demonstration ◽  
Content Type ◽  
Control Approach ◽  
Cartesian Space ◽  
Compliant Behavior ◽  
Dynamic Movement Primitives

Purpose This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration. Design/methodology/approach A modified dynamic movement primitives (DMPs) model with a novel hybrid force/position feedback in Cartesian space for the robotic PiH problem is proposed by learning from demonstration. To ensure a compliant interaction during the PiH insertion process, a Cartesian impedance control approach is used to track the trajectory generated by the modified DMPs. Findings The modified DMPs allow the robot to imitate the trajectory of demonstration efficiently and to generate a smoother trajectory. By taking advantage of force feedback, the robot shows compliant behavior and could adjust its pose actively to avoid a jam. This feedback mechanism significantly improves the dynamic performance of the interactive process. Both the simulation and the PiH experimental results show the feasibility and effectiveness of the proposed model. Originality/value The trajectory and the compliant manipulation skill of the human operator can be learned simultaneously by the new model. This method adopted a modified DMPs model in Cartesian space to generate a trajectory with a lower speed at the beginning of the motion, which can reduce the magnitude of the contact force.

Analysis and simulation of a new Cartesian cable-suspended robot

2009 ◽  
Vol 224 (8) ◽  
pp. 1717-1726 ◽  
Author(s):  
G Castelli ◽  
E Ottaviano ◽  
A González
Keyword(s):  
Numerical Simulation ◽  
Degrees Of Freedom ◽  
Robot Arm ◽  
Fixed Frame ◽  
Cartesian Space ◽  
Compliant Assembly ◽  
Moving Platform ◽  
Geometry Analysis ◽  
Three Degrees Of Freedom

In this article, a manipulator is presented belonging to the class of cable-suspended robots, for which the cable length variations are related by suitable functions in order to achieve specific kinematic characteristics. In particular, in this article, a Cartesian cable-suspended robot is proposed that has eight cables to have three degrees of freedom (DOF) in Cartesian space. The eight cables of the robot are arranged in parallel by pairs with identical length, with the aim of constraining the moving platform to keep a constant orientation with respect to the fixed frame. The robot can be used for selective compliant assembly robot arm (SCARA) motions (when an additional revolute actuated joint is placed on the moving platform) for a variety of applications in which a large workspace is required. In this article, a geometry analysis of the robot is presented together with a numerical simulation of the kinetostatics and dynamics to investigate the robot's performances in several operative conditions. Furthermore, a characterization of the position workspace regions is reported for this cable-suspended robot.

Joint position-based impedance control with load compensation for robot arm

2015 ◽  
Vol 39 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Shih-Hsuan Chiu ◽  
Cheng-Chin Chen ◽  
Kun-Ting Chen ◽  
Xin-Jie Huang ◽  
Sheng-Hong Pong
Keyword(s):  
Impedance Control ◽  
Joint Position ◽  
Robot Arm ◽  
Load Compensation

scholarly journals Optical Torque Sensors for Local Impedance Control Realization of an Anthropomorphic Robot Arm

2006 ◽  
Vol 18 (2) ◽  
pp. 121-130 ◽  
Author(s):  
Dzmitry Tsetserukou ◽  
◽  
Riichiro Tadakuma ◽  
Hiroyuki Kajimoto ◽  
Susumu Tachi
Keyword(s):  
Strain Gauge ◽  
Impedance Control ◽  
Robot Arm ◽  
Torque Sensor ◽  
Optical Torque

We recently developed an optical torque sensor to replace expensive strain-gauge-based sensor on the anthropomorphic robot arm and realize local impedance control in individual joints.

On the role of stiffness and synchronization in human–robot handshaking

2020 ◽  
Vol 39 (14) ◽  
pp. 1796-1811 ◽  
Author(s):  
Domenico Mura ◽  
Espen Knoop ◽  
Manuel G Catalano ◽  
Giorgio Grioli ◽  
Moritz Bächer ◽  
...  
Keyword(s):  
Personality Traits ◽  
Impedance Control ◽  
Robotic Arm ◽  
Robot Arm ◽  
Passive Behavior ◽  
Arm Motions ◽  
Human Arm ◽  
Human Likeness

This article presents a system for soft human–robot handshaking, using a soft robot hand in conjunction with a lightweight and impedance-controlled robot arm. Using this system, we study how different factors influence the perceived naturalness, and give the robot different personality traits. Capitalizing on recent findings regarding handshake grasp force regulation, and on studies of the impedance control of the human arm, we investigate the role of arm stiffness as well as the kinesthetic synchronization of human and robot arm motions during the handshake. The system is implemented using a lightweight anthropomorphic arm, with a Pisa/IIT Softhand wearing a sensorized silicone glove as the end-effector. The robotic arm is impedance-controlled, and its stiffness changes according to different laws under investigation. An internal observer is employed to synchronize the human and robot arm motions. Thus, we simulate both active and passive behavior of the robotic arm during the interaction. Using the system, studies are conducted where 20 participants are asked to interact with the robot, and then rate the perceived quality of the interaction using Likert scales. Our results show that the control of the robotic arm kinesthetic behavior does have an effect on the interaction with the robot, in term of its perceived personality traits, responsiveness, and human-likeness. Our results pave the way towards robotic systems that are capable of performing human–robot interactions in a more human-like manner, and with personality.

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.

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