Motion Control Algorithms for Sensor-Equipped Robots

1987 ◽  
Vol 109 (4) ◽  
pp. 335-344 ◽  
Author(s):  
M. Shoham ◽  
Y. Koren
Keyword(s):  
Coordinate System ◽  
Motion Control ◽  
Inverse Kinematics ◽  
Sufficient Conditions ◽  
Design Stage ◽  
Control Algorithms ◽  
Target Point

This paper deals with the development of kinematic algorithms for the control of sensor-equipped robots. The kinematics is solved in the sensor coordinate system, which reduces the computation efforts, and allows the elimination of the first joint encoder. Simplification of the algorithms can be obtained when approximations are used to solve the inverse kinematics. Three control algorithms based on approximations are presented. However, with these algorithms, convergence to the target is not always guaranteed. A Theorem which specifies the sufficient conditions required for a trajectory to converge to a target point is proved. Based on this Theorem robot parameters can be selected in the design stage of the manipulator. This is illustrated for several types of manipulators.

scholarly journals Design and Implementation of Inverse Kinematics and Motion Monitoring System for 6Dof Platform

2021 ◽  
Vol 11 (19) ◽  
pp. 9330
Author(s):  
Ming-Yen Wei
Keyword(s):  
Motion Control ◽  
Inverse Kinematics ◽  
Control Algorithms ◽  
Design And Implementation ◽  
Motion Control Card ◽  
Machine Interface ◽  
Rotor Angle ◽  
Measurement Software ◽  
Displacement Speed ◽  
High Degree

Six-axis motion platforms have a low contraction height and a high degree of freedom. First of all, the designed six-axis crank arm platform, including the motor, reducer, crank arm, link, platform support arm, and upper and lower platforms, can be designed for different bearing requirements. Secondly, it uses a coordinate transform and kinematics theory to derive each motor rotor angle. A set of platform data acquisition (DAQ) monitoring modules was established, and the LabVIEW programming language was used to write measurement software. The monitoring items include displacement, speed, and acceleration, which can be displayed on the screen and recorded by an industrial computer in real time and dynamically. Then, an RS-485 or RS-232 communication transmission interface was used to provide the control system with the related movement information. Finally, an industrial computer combined with a motion control card was used as a control kernel to realize the control algorithms, internet module function, I/O write and read signals, firmware integration, and human–machine interface message. The experimental results validate the appropriateness of the proposed method.

Effects of Dynamic Model Errors in Task-Priority Operational Space Control

Robotica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Paolo Di Lillo ◽  
Gianluca Antonelli ◽  
Ciro Natale
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Null Space ◽  
Control Algorithms ◽  
Model Errors ◽  
Operational Space ◽  
Dynamic Level ◽  
Concurrent Tasks ◽  
Modeling Errors

SUMMARY Control algorithms of many Degrees-of-Freedom (DOFs) systems based on Inverse Kinematics (IK) or Inverse Dynamics (ID) approaches are two well-known topics of research in robotics. The large number of DOFs allows the design of many concurrent tasks arranged in priorities, that can be solved either at kinematic or dynamic level. This paper investigates the effects of modeling errors in operational space control algorithms with respect to uncertainties affecting knowledge of the dynamic parameters. The effects on the null-space projections and the sources of steady-state errors are investigated. Numerical simulations with on-purpose injected errors are used to validate the thoughts.

scholarly journals Autonomous Navigation of a Team of Unmanned Surface Vehicles for Intercepting Intruders on a Region Boundary

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 297
Author(s):  
Ali Marzoughi ◽  
Andrey V. Savkin
Keyword(s):  
Motion Control ◽  
Autonomous Vehicles ◽  
Autonomous Navigation ◽  
Control Algorithm ◽  
Autonomous Vehicle ◽  
Sufficient Conditions ◽  
Real Life ◽  
Unmanned Surface Vehicles ◽  
Necessary And Sufficient ◽  
See Region

We study problems of intercepting single and multiple invasive intruders on a boundary of a planar region by employing a team of autonomous unmanned surface vehicles. First, the problem of intercepting a single intruder has been studied and then the proposed strategy has been applied to intercepting multiple intruders on the region boundary. Based on the proposed decentralised motion control algorithm and decision making strategy, each autonomous vehicle intercepts any intruder, which tends to leave the region by detecting the most vulnerable point of the boundary. An efficient and simple mathematical rules based control algorithm for navigating the autonomous vehicles on the boundary of the see region is developed. The proposed algorithm is computationally simple and easily implementable in real life intruder interception applications. In this paper, we obtain necessary and sufficient conditions for the existence of a real-time solution to the considered problem of intruder interception. The effectiveness of the proposed method is confirmed by computer simulations with both single and multiple intruders.

Starting Processes in Electric Drive of a Passenger Elevator

2021 ◽  
Vol 1 (1) ◽  
pp. 40-49
Author(s):  
S. Rachev ◽  
K. Dimitrova ◽  
D. Koeva ◽  
L. Dimitrov
Keyword(s):  
Coordinate System ◽  
Induction Motor ◽  
Electric Drive ◽  
High Speed ◽  
Induction Motors ◽  
Dynamic Loads ◽  
Design Stage ◽  
Motor Drive ◽  
Induction Motor Drive ◽  
Electric Induction

During the operation of electric induction motors used to drive passenger elevators, electro-mechanical transient processes occur, which can cause unacceptable dynamic loads and vibrations. In this regard, research is needed both at the design stage and for operating elevator systems to determine the arising impact currents and torques, in order to propose solutions for their limitation within pre-set limits. Paper deals with starting processes in a two-speed induction motor drive of a passenger elevator. The equations for the voltages of the induction motor are presented in relative units in a coordinate system rotating at a synchronous speed. The values have been obtained for the torques, the rotational frequencies and the currents when starting at a high speed and passing from high to low speed.

A Service Robot with Lightweight Arms and a Trinocular Vision Sensor

2010 ◽  
Vol 439-440 ◽  
pp. 396-400
Author(s):  
Xian Hua Li ◽  
Shi Li Tan ◽  
Wu Xin Huang
Keyword(s):  
Control System ◽  
Coordinate System ◽  
Inverse Kinematics ◽  
Robot Control ◽  
Service Robot ◽  
Algebraic Solution ◽  
Vision Sensor ◽  
Solution Methods ◽  
Space Coordinate ◽  
Position And Orientation

This paper describes a household service robot with two lightweight arms and a trinocular vision sensor. According to DH convention, the coordinate system of two arms is established, and position and orientation of the hand is computed. The inverse kinematics of the arm is solved with geometric and algebraic solution methods. By the trinocular vision sensor, robot can recognize the bottle and get its 3-D space coordinate. Through experiments, both correctness of the algorithm and stability of the robot control system are validated.

A Variational Approach for Modeling Flexibility Effects in Manipulator Arms

Robotica ◽  
1991 ◽  
Vol 9 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Ali Meghdari
Keyword(s):  
Motion Control ◽  
Variational Approach ◽  
Control Algorithms ◽  
General Technique ◽  
Robotic Arms ◽  
Cartesian Space ◽  
The Matrix ◽  
Structural Deformations ◽  
Castigliano’S Theorem ◽  
Compliance Coefficients

SUMMARYThis paper presents a general technique to model flexible components (mainly links and joints flexibilities are considered) of manipulator arms based on Castigliano's theorem of least work. The robotic arms flexibility properties are derived and represented by the matrix of compliance coefficients. Such expressions can be used to determine the errors due to the robotic tip deformations under the application of a set of applied loads at the tip in a Cartesian space. Once these deformations are computed, they may be used to correct for the positional errors arisen from the robotic structural deformations in the motion control algorithms.

MBARS2: A New Design for a 3- Degrees of Freedom Parallel Structure for Joint Arthroplasty

2008 ◽  
Author(s):  
A. Wolf ◽  
S. Amir ◽  
A. B. Mor
Keyword(s):  
Coordinate System ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Joint Arthroplasty ◽  
Robotic System ◽  
Parallel Structure ◽  
Tracking Systems ◽  
Mechanical Structure ◽  
Workspace Analysis

In this report we present the second prototype of a 3-degrees-of-freedom active, miniature bone-attached, robotic system. The report focuses on the mechanical structure, workspace analysis and inverse kinematics solution. The robot is capable of preparing the bone cavity for an implant during joint arthroplasty procedures. This system, just as its predecessor is image-free and all planning is performed intraoperatively in the robot coordinate system, eliminating the need for external tracking systems in the OR. Experiments were conducted using the first robot prototype to evaluate its accuracy and the results supported the feasibility of the concept.

Regulating a Formation of a Large Number of Vehicles

2005 ◽  
Author(s):  
Akira Okamoto ◽  
Dean B. Edwards
Keyword(s):  
Control Problem ◽  
Coordinate System ◽  
Formation Control ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Relative Distance ◽  
Control Algorithms ◽  
Distance Measurements ◽  
Six Degree Of Freedom

Various control algorithms have been developed for fleets of autonomous vehicles. Many of the successful control algorithms in practice are behavior-based control or nonlinear control algorithms, which makes analyzing their stability difficult. At the same time, many system theoretic approaches for controlling a fleet of vehicles have also been developed. These approaches usually use very simple vehicle models such as particles or point-mass systems and have only one coordinate system which allows stability to be proven. Since most of the practical vehicle models are six-degree-of-freedom systems defined relative to a body-fixed coordinate system, it is difficult to apply these algorithms in practice. In this paper, we consider a formation regulation problem as opposed to a formation control problem. In a formation control problem, convergence of a formation from random positions and orientations is considered, and it may need a scheme to integrate multiple moving coordinates. On the contrary, in a formation regulation problem, it is not necessary since small perturbations from the nominal condition, in which the vehicles are in formation, are considered. A common origin is also not necessary if the relative distance to neighbors or a leader is used for regulation. Under these circumstances, the system theoretic control algorithms are applicable to a formation regulation problem where the vehicle models have six degrees of freedom. We will use a realistic six-degree-of-freedom model and investigate stability of a fleet using results from decentralized control theory. We will show that the leader-follower control algorithm does not have any unstable fixed modes if the followers are able to measure distance to the leader. We also show that the leader-follower control algorithm has fixed modes at the origin, indicating that the formation is marginally stable, when the relative distance measurements are not available. Multi-vehicle simulations are performed using a hybrid leader-follower control algorithm where each vehicle is given a desired trajectory to follow and adjusts its velocity to maintain a prescribed distance to the leader. Each vehicle is modeled as a three-degree-of-freedom system to investigate the vehicle’s motion in a horizontal plane. The examples show efficacy of the analysis.

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