Robotic Force Control Using Virtual Trajectory Generation

1999 ◽  
Vol 121 (2) ◽  
pp. 320-322
Author(s):  
Timothy S. Fielding ◽  
James K. Mills
Keyword(s):  
Force Control ◽  
Control Algorithm ◽  
Control Method ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Initial Value ◽  
Control Capability ◽  
Six Degree Of Freedom ◽  
Virtual Trajectory ◽  
Contact Force Control

A control method is introduced to permit the retrofit of a large class of commercially available industrial robots with a contact force control capability. In this control algorithm, the outer force loop modifies the desired position input trajectory by solving two sets of differential equations as initial value problems. Experimental results, obtained on a CRS Robotics Corporation A460 six degree of freedom industrial robot, are presented which demonstrate the effectiveness of the proposed approach.

A Polishing Robot Force Control System Based on Time Series Data in Industrial Internet of Things

2021 ◽  
Vol 21 (2) ◽  
pp. 1-22
Author(s):  
Chen Zhang ◽  
Zhuo Tang ◽  
Kenli Li ◽  
Jianzhong Yang ◽  
Li Yang
Keyword(s):  
Time Series ◽  
Control System ◽  
Force Control ◽  
Time Series Data ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Series Data ◽  
Industrial Internet Of Things ◽  
Industrial Internet ◽  
Force Control System

Installing a six-dimensional force/torque sensor on an industrial arm for force feedback is a common robotic force control strategy. However, because of the high price of force/torque sensors and the closedness of an industrial robot control system, this method is not convenient for industrial mass production applications. Various types of data generated by industrial robots during the polishing process can be saved, transmitted, and applied, benefiting from the growth of the industrial internet of things (IIoT). Therefore, we propose a constant force control system that combines an industrial robot control system and industrial robot offline programming software for a polishing robot based on IIoT time series data. The system mainly consists of four parts, which can achieve constant force polishing of industrial robots in mass production. (1) Data collection module. Install a six-dimensional force/torque sensor at a manipulator and collect the robot data (current series data, etc.) and sensor data (force/torque series data). (2) Data analysis module. Establish a relationship model based on variant long short-term memory which we propose between current time series data of the polishing manipulator and data of the force sensor. (3) Data prediction module. A large number of sensorless polishing robots of the same type can utilize that model to predict force time series. (4) Trajectory optimization module. The polishing trajectories can be adjusted according to the prediction sequences. The experiments verified that the relational model we proposed has an accurate prediction, small error, and a manipulator taking advantage of this method has a better polishing effect.

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

scholarly journals Comparison of Contact Force Control Strategies on Different Robot Arm Types

2010 ◽  
Author(s):  
Hu¨seyin Yaltirik ◽  
A. Kerim Kar ◽  
Bu¨lent Ekici
Keyword(s):  
Force Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Control Algorithms ◽  
Robot Arm ◽  
Interaction Forces ◽  
Static Contact ◽  
Contact Tasks ◽  
Control Interaction ◽  
Contact Force Control

Nowadays robots are used in various areas. There are extremely important applications where the robot arm tip comes in contact with the environment or an object. During controlling an object, static or in motion, the object or the robot arm should not be damaged. The interaction forces are important in such conditions. Whether the task succeeds or fails depends on how accurate the interaction forces are controlled. The interaction forces are changed depending on the motion of the robot arm. Therefore, to control interaction forces a force control algorithm must be developed. In this research a force control algorithm will first be developed for the quasi-static contact tasks, then it will be extended to the dynamic cases. The goal of this study is to compare force control strategies to achieve the desired interaction forces between the robot arm tip (end-effector) and the environment during contact tasks. Taguchi L9 method is used for comparison of selected force control algorithms which are modeled in SIMULINK MATLAB program.

An Analytical Inverse Kinematics Solution Method for Robotic Manipulators

2000 ◽  
Author(s):  
Tuna Balkan ◽  
M. Kemal Özgören ◽  
M. A. Sahir Arikan ◽  
H. Murat Baykurt
Keyword(s):  
Inverse Kinematics ◽  
Industrial Robot ◽  
Robotic Manipulators ◽  
Inverse Kinematic ◽  
Industrial Robots ◽  
Solution Approach ◽  
Joint Variable ◽  
Forward Kinematic ◽  
Six Degree Of Freedom ◽  
Kinematic Solution

Abstract In this study, an inverse kinematic solution approach applicable to six degree-of-freedom industrial robotic manipulators is introduced. The approach is based on a previously introduced kinematic classification of industrial robotic manipulators by Balkan et al. (1999), and depending on the kinematic structure, either an analytical or a semi-analytical inverse kinematic solution is obtained. The semi-analytical method is named as the parametrized joint variable (PJV) method. Compact forward kinematic equations obtained by utilizing the properties of exponential rotation matrices. In the inverse kinematic solutions of the industrial robots surveyed in the previous study, most of the simplified compact equations can be solved analytically and the remaining few of them can be solved semi-analytically through a numerical solution of a single univariate equation. In these solutions, the singularities and the multiple configurations of the manipulators can be determined easily. By the method employed in this study, the kinematic and inverse kinematic analysis of any manipulator or designed-to-be manipulator can be performed and using the solutions obtained, the inverse kinematics can also be computerized by means of short and fast algorithms. As an example for the demonstration of the applicability of the presented method to manipulators with closed-chains, ABB IRB2000 industrial robot is selected which has a four-bar mechanism for the actuation of the third link, and its compact forward kinematic equations are given as well as the inverse kinematic solution.

A Semiparametric Model-Based Friction Compensation Method for Multi-Joint Industrial Robot

2021 ◽  
Author(s):  
Miao He ◽  
Xiaomin Wu ◽  
Guifang Shao ◽  
Yuhua Wen ◽  
Tundong Liu
Keyword(s):  
Industrial Robot ◽  
Lyapunov Theory ◽  
Industrial Robots ◽  
Learning Ability ◽  
Robot System ◽  
Joint Friction ◽  
Tracking Tasks ◽  
Physical Information ◽  
The Stability ◽  
Six Degree Of Freedom

Abstract Industrial robots have received enormous attention due to their widespread uses in modern manufacturing. However, due to the frictional discontinuous and other unknown dynamics in robotic system, existing researches are limited to simulation and single- or double-joint robot. In this paper, we introduce a semiparametric controller combined by a radial basis function neural network (RBFNN) and complete physical model considering joint friction. First, to extend the NN controller to real-world problems, the continuously differentiable friction (CDF) model is adopted to bring physical information into the learning process. Then, RBFNN is employed to approximate the model error and other unmolded dynamics, and the parameters of CDF model are updated online according to its learning ability. The stability of the robot system can be guaranteed by the Lyapunov theory. The primary parameters of CDF model are determined by the identification experiment and subsequently iteratively updated by the NN. Real-time tracking tasks are performed on a six degree of freedom (DoF) manipulator to follow the desired trajectory. Experimental results demonstrate the effectiveness and superiority of the proposed controller, especially at low speed.

Force Control Based on Model Predictive for Lower Limb Rehabilitation Training

2015 ◽  
Vol 738-739 ◽  
pp. 991-994
Author(s):  
Fu Cheng Cao ◽  
Hong Wu Qin
Keyword(s):  
Force Control ◽  
Lower Limb ◽  
Control Method ◽  
Control Strategies ◽  
Industrial Robot ◽  
Control Law ◽  
Rehabilitation Robot ◽  
Patient Centered ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

Human as a varying dynamic system, the control strategies of human-robot interacts differ significantly from that of conventional industrial robot. Considered the patient-centered exercise regimens, a force control method based predict is presented to control a lower limb rehabilitation robot. The control law is introduced that optimises the the maintained force level and limits excessive forceto injury the subject's lower extremity joints. Simulation results show that the robot could guide thelower limb of subjects to move under predefined model of the external force.

Research on Contact Force Control in Process of Aspheric Surface Polish

2012 ◽  
Vol 621 ◽  
pp. 216-222
Author(s):  
Jie Qiong Lin ◽  
Tong Huan Ran ◽  
Li Feng
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Position Control ◽  
Control Method ◽  
Free Form ◽  
Force Output ◽  
Compliant Control ◽  
Free Form Surface ◽  
Polishing Tool ◽  
Contact Force Control

Contact force control is one of the key technologies of polishing aspheric optical parts, and keeping a stable polishing contact force on the basis of accurate position control is an important condition to obtain high quality aspheric. The paper bases on ideal surface, decouples the contact force that between polishing tool and workpiece in each direction of the drive shaft in process of polish. Then get output force of all sports shaft. Finally, realize the polishing contact force control that take the position as a control goals, and take constant force output as a constraints. Simulation results show that the control method can achieve constant contact force output in the processing of polishing free-form surface, which provide a new idea to research the compliant control of polishing free-form surface.

Position-Force Control for a Six Coordinate Industrial Robot when Performing Complicated Surface Treatment

2019 ◽  
Vol 20 (1) ◽  
pp. 34-43
Author(s):  
V. L. Afonin ◽  
L. V. Gavrilina ◽  
A. N. Smolentsev
Keyword(s):  
Surface Treatment ◽  
Control Method ◽  
Industrial Robot ◽  
Complex Surface ◽  
Industrial Robots ◽  
Complex Surfaces ◽  
Simultaneous Control ◽  
Cutting Surface ◽  
Assembly Operations ◽  
Executive Body

When performing certain technological operations, multi-coordinate industrial robots require simultaneous control of the movement of the executive body and the developed effort. When performing assembly operations (for example, a shaft with a bush), it is necessary to perform a free movement of the shaft along the bore of the bushing and to ensure minimum pressure on the bore walls. When performing operations to handle complex surfaces of parts, it is simultaneously required to move the tool over the surface at a specified speed and to perform a metered pressure on the surface. Since it is impossible to control the force and motion simultaneously at the same coordinate, it is necessary either to switch from one control method to another, or to control various actuators and different controllable coordinates of the actuator. In multi-coordinate robots, this task is complicated by the fact that to control the movement of one of the Cartesian coordinates of the executive body, and by another force, it is simultaneously necessary to control the interrelated generalized coordinates of the robot’s mechanism. In the work presented, the solution of the problem of control of a six-coordinate industrial robot is described, in which the separation of the degrees of mobility into power control and positional control of trajectory motion is carried out. In order to accomplish the task, additional variable parameters are introduced for the treatment of complex surfaces, which determine the position of the cutting edge on the cutting surface, which makes it possible to expand the service area of the robot during selection, for example, one of the coordinates for controlling the pressure force. This task is considered using the example of a six-coordinate industrial robot when performing a complex surface treatment operation, when it is required to program the tool at a specified speed along a path on the surface and at the same time carry out the controlled pressure of the tool on the surface.

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