A Surface Interpolation Scheme Based on the Theory of Conjugate Surfaces

1994 ◽  
Author(s):  
Chih-Hsin Chen
Keyword(s):  
Robot Motion ◽  
Interpolation Point ◽  
Interpolation Scheme ◽  
Base Plane ◽  
End Effector ◽  
Surface Interpolation ◽  
Surface Patches ◽  
Moving Base ◽  
Conjugate Surfaces ◽  
Interpolation Functions

Abstract A surface interpolation scheme is described for interpolating an array of knot points and normals. The scheme is based on the generation of interpolation surface patches by envelopment of a moving base plane which is fixed in the end effector of a robot of two revolute pairs and one prismatic pair. The initial values, the control values, and the interpolation functions of the robot motion are discussed. The equations for determining the geometrical values of an interpolation point are derived with the aid of the theory of conjugate surfaces, and are arranged in order of the corresponding algorithm. The continuity between neighboring interpolation surface patches is proved to be C1.5. The feasibility of improving the continuity by adjusting the control values of the robot motion is investigated.

Finding Features of Positioning Error for Large Industrial Robots Based on Convolutional Neural Network

2021 ◽  
Author(s):  
Daiki Kato ◽  
Kenya Yoshitugu ◽  
Naoki Maeda ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Production Systems ◽  
Industrial Robot ◽  
Three Dimensional ◽  
Industrial Robots ◽  
Numerical Control ◽  
Robot Motion ◽  
Positioning Error ◽  
End Effector

Abstract Most industrial robots are taught using the teaching playback method; therefore, they are unsuitable for use in variable production systems. Although offline teaching methods have been developed, they have not been practiced because of the low accuracy of the position and posture of the end-effector. Therefore, many studies have attempted to calibrate the position and posture but have not reached a practical level, as such methods consider the joint angle when the robot is stationary rather than the features during robot motion. Currently, it is easy to obtain servo information under numerical control operations owing to the Internet of Things technologies. In this study, we propose a method for obtaining servo information during robot motion and converting it into images to find features using a convolutional neural network (CNN). Herein, a large industrial robot was used. The three-dimensional coordinates of the end-effector were obtained using a laser tracker. The positioning error of the robot was accurately learned by the CNN. We extracted the features of the points where the positioning error was extremely large. By extracting the features of the X-axis positioning error using the CNN, the joint 1 current is a feature. This indicates that the vibration current in joint 1 is a factor in the X-axis positioning error.

Control of a mobile robotic manipulator: a combined design approach

2018 ◽  
Author(s):  
Martín Crespo ◽  
Matías Nacusse ◽  
Sergio Junco ◽  
Vitalram Rayankula ◽  
Pushparaj Mani Pathak
Keyword(s):  
Arm Movement ◽  
Backstepping Technique ◽  
Energy Shaping ◽  
End Effector ◽  
Dc Motors ◽  
Operational Space ◽  
Control Actions ◽  
Moving Base ◽  
The One ◽  
Mobile Base

"This paper focuses on the problem of reducing via control actions the interaction between the mobile platform and the arm in a mobile robot equipped with a redundant planar manipulator. It is solved maintaining the mobile base as immobile as possible once it has been moved to a desired position, which serves to a double purpose. On the one hand, it helps keeping fixed the workspace of the manipulator, as predefined in the world coordinates, in order for the end-effector being able to reach the points where it has to perform its tasks. On the other hand, as this reduces the disturbances that the otherwise moving base would introduce on the arm movement, this serves to improve the precision in the execution of whatever task the end-effector has to perform. The problem is solved via a combination of operational space control to solve the arm tip trajectory tracking problem and energy-shaping and damping assignment to restrict the movement of the mobile base. The latter is achieved using a backstepping technique in the Bond Graph domain which emulates dissipation and stiffness at the base wheels coordinates through the control of the DC motors actuating them. Simulation results show the good performance of the control system."

Loci Conversion and Corner Smoothing with PH Curves in CNC System

2009 ◽  
Vol 419-420 ◽  
pp. 161-164
Author(s):  
Qi Kui Wang ◽  
You Dong Chen ◽  
Wei Li ◽  
Tian Miao Wang ◽  
Hong Xing Wei
Keyword(s):  
Tangent Vector ◽  
Machining Process ◽  
Free Form ◽  
Surface Interpolation ◽  
Pythagorean Hodograph ◽  
Linear Elements ◽  
Smoothing Process ◽  
Ph Curve ◽  
Interpolation Functions ◽  
Tangent Vectors

Free-form surface interpolation functions give more advantages in machining than the traditional line and circle functions. A method is developed to convert lines and circles into Pythagorean-hodograph (PH) curves. In order to get smooth machining process the PH curve is used to replace the joints of the circular/linear elements by the connection situation. The slope of line is used to get the tangent vector in the line conversion. When converting a circle to a PH curve, points of the divided circle are introduced to compute the vectors. The methods of computing tangent vectors are proposed according to the slope of the line and the quadrant of the circle. The transformation errors from lines and circles to PH curves are computed. In the corner smoothing process the tangent vectors are computed by the connection between lines and circles. Replacement errors at the joints are computed for the use of PH curve. The results demonstrate the feasibility of the conversion from line and circle to PH curve. The PH curves at the joints of the circular and linear elements show continuous trajectory.

scholarly journals Design and Fabrication of 3-DOF Robot Arm Using Parallelogram Mechanisms

2021 ◽  
Vol 9 (9) ◽  
pp. 1224-1229
Keyword(s):  
Robotic Arm ◽  
Robot Motion ◽  
3D Printer ◽  
File Format ◽  
Robot Arm ◽  
End Effector ◽  
Stl File ◽  
Stepper Motors ◽  
And Control

This paper focuses on the design, fabrication and control of a 3-DOF robot arm using stepper motors. The robot arm uses three parallelogram mechanisms to position the end-effector of the robot and keep the end-effector always parallel to the horizontal during the robot motion. The robot is designed on the Autodesk Inventor software. Separated parts of the robot are saved in the stereolithography (STL) file format. Then the parts are fabricated by a 3D printer. The movement of the robotic arm is driven by stepper motors and controlled by Arduino. The Arduino board implements kinematics calculation, creates pulses and sends them to three drivers to driven stepper motors. A software is developed to control the robot by sending the command to the Arduino board.

Object Manipulation Using Kinect as the 3D Sensor

2013 ◽  
Vol 432 ◽  
pp. 437-441
Author(s):  
Dong Whan Kim ◽  
Jong Eun Ha
Keyword(s):  
Inverse Kinematics ◽  
Target Location ◽  
Vertical Plane ◽  
Object Manipulation ◽  
Robot Motion ◽  
Laser Range Finder ◽  
End Effector ◽  
Laser Range ◽  
3D Data ◽  
Feedback Style

ndustrial robot can extend its capability adopting sensors such as camera and laser range finder. In this paper, we deal with object manipulation including grasping objects on the table and inserting them into the hole on the vertical plane. Kinect is used as the 3D sensor. First, object location and target location is computed after processing 3D data. Robot motion obtained by solving inverse kinematics can have errors so that we adopt visual feedback style approach. Chessboard type marker is attached on the end-effector of the robot and its location with respect to the target is used to correct the robot motion.

Geometric Trajectory Planning for Robot Motion Over a 3D Surface

2019 ◽  
Author(s):  
Bashir Hosseini Jafari ◽  
Nolan Walker ◽  
Ronald Smaldone ◽  
Nicholas Gans
Keyword(s):  
Motion Planning ◽  
Specific Region ◽  
Robot Motion ◽  
Trajectory Design ◽  
Curved Surfaces ◽  
End Effector ◽  
Surface Parameterization ◽  
3D Surface ◽  
Distortion Analysis ◽  
2D Pattern

Abstract Mapping a desired 2D pattern onto a curved surface has many applications. This includes motion planning for mobile robots to perform coverage path planing, robot end effector trajectory design for tasks such as printing, depositing, wielding on a 3D surface. This problem becomes more difficult if we want the mapped pattern to keep the properties of the original pattern (i.e, least possible mapping distortion), and pass over some desired points and/or remain bounded in a specific region on the surface. In this paper, we apply surface parameterization and mapping distortion analysis, which is rarely used in robot motion planning works, to map a pattern onto 3D surface. To meet additional goals such as passing over certain points, a planar mapping determined by constrained optimization is employed on the original pattern. Our focus is on printing/depositing materials on curved surfaces, and simulations and experiments are provided to confirm the performance of the approach.

scholarly journals Kinematic Modelling of a Robot in Form-shaping Milling Complex Surfaces

2019 ◽  
Vol 4 (11) ◽  
pp. 26-31 ◽  
Author(s):  
Ha Thanh Hai
Keyword(s):  
Degrees Of Freedom ◽  
Machining Process ◽  
Multidimensional Space ◽  
Robot Motion ◽  
Machining Efficiency ◽  
Complex Surfaces ◽  
End Effector ◽  
Observation Area ◽  
Kinematic Modelling ◽  
6 Degrees Of Freedom

This paper presents kinematic modelling of a robot in form-shaping milling complex surfaces, illustrated applying in form-shaping milling a molding prototype. The robot have 6 degrees of freedom, with a cutter attaching to the end of the end-effector. The workpiece is fixed on the clamping table. Using robot in form-shaping machining parts enables increasing the flexibility of selecting machining observation area, increasing capability of selecting engineering manipulation, increasing quality and machining efficiency. In machining process, because of the cutter moving along the machining trajectory in multidimensional space, computing and planning trajectory is more complex. In order to planning the trajectory, it need to derive the kinematic equations of the robot, and deal with the kinematic problems. The kinematics problems are solved with the constraints that the position, orientation, velocity of the tool frame must be coincided with the ones of the workpiece frame. After computing, the results are validated by simulation of robot motion.

Transplanting Path Planning and Motion Functions Research of the High-Speed Tray Seedling Transplanting Robot

2013 ◽  
Vol 694-697 ◽  
pp. 1747-1752 ◽  
Author(s):  
Jun Ma ◽  
Jian Ping Hu ◽  
Xiao Yue Yan ◽  
Chun Hui Qi ◽  
Jing Guan
Keyword(s):  
Parallel Mechanism ◽  
High Speed ◽  
Trajectory Analysis ◽  
Robot Motion ◽  
Low Density ◽  
End Effector ◽  
Quintic Polynomial ◽  
Movement Characteristic ◽  
Movement Function ◽  
The Stability

High-speed tray seedling transplanting robot was developed which used two-DOF parallel mechanism as transplanting mechanism, and pneumatic manipulator as the end-effector, so it can achieve high speed of transplanting. According to transplanting seedlings from high-density plug to the low-density plug, a type of transplanting path was put forward which consists of rise, translation and decline, in this paper, it was called three-stage trajectory. Analysis the movement characteristic of each stage, make sure the stability of transplanting, then the sine motion law, quintic polynomial motion law and septic polynomial motion law were put forward as the Transplanting movement function according the analysis of movement characteristic. Compared the transplanting efficiency and stability of the three motion law through their velocity, acceleration and saltus, finally, quintic polynomial motion law was preferred as transplanting robot motion law. Transplanting experiment was taken on the developed prototype, the transplanting frequency was more than 60 per minute and the qualified rate can reach 92.71%.

Sign in / Sign up

Export Citation Format

Share Document