Kinematic Model Of Robot Research Articles

Study on formation control system for underwater spherical multi-robot

Aiming at multi robot cooperation application requirements of our small-scaled underwater spherical robots, a cooperative formation control system with static and dynamic target rounding up was proposed and studied in this paper. Considering the complex underwater environment and kinematic modeling of the robot, a simplified kinematic model of underwater spherical robot with horizontal and vertical motion was established. Given the environmental disturbances in practical underwater scenarios, an adaptive control algorithm was designed to control the underwater spherical robot, which has good robustness and adaptability. To handle the application requirement of static and dynamic target rounding up with multi robots, the path planning strategy of multi robot was proposed, the modeling of static and dynamic target rounding up was analyzed and optimized, and a controller based on linear quadratic regulator method was also designed to realize static/dynamic target rounding up with multi robots. In addition, underwater target rounding up experiments with two or three spherical robots were conducted to test the feasibility and performance of the proposed formation control system, and the experimental results confirmed the validity of the proposed system. This study may inspire future underwater multi robot cooperation that have properties of high efficiency, wide range and multi tasks and has low environmental interference of aquatic environments.

Collective Tasks for a Flock of Robots Using Influence Factor

In this paper, a form of steering a swarm of robots is presented using behavior local rules that depends on four parameters. These parameters are related with a general model of the behavior of social animals called repulsion, attraction orientation and influence. By simulations, a kinematic and dynamical math models of robots were made for testing its performance as a swarm and to know the impact of the parameters considering two tasks of location and navigation considering aggregation and flocking as a minimum condition that the swarm must have. An implementation was made building a flock of simple robots with hardware and software limitations. Some statistics to measure the performance of the swarm considering its covered area are proposed and analyze the impact of parameters on the swarm. Results of simulation are similar to the implementations as expected. The proposed behavior rules based on repulsion, attraction and orientation determine the formation of the swarm or the flock and influence emphasizes the principal task; in other words, associate a specific task with a specific perception or signal.

A Novel Path Control Algorithm for Networked Underwater Robot

Under the network environment, the traditional control method of underwater Robot path has the disadvantages of low control accuracy, large error, and inefficiency. This paper proposes a novel path control method for underwater Robots based on the NURBS (nonuniform rational B-spline, NURBS) curve fitting method, which utilizes a sensor or camera to detect the static and dynamic obstacles, establishes the kinematics model of underwater Robots, gets the target function of rob shortest path, and analyzes underwater Robot constraints. According to the basic fluid mechanics, the resistance of the underwater Robot is determined. The filter function is used to smooth the process, and the NURBS curve fitting method is applied to control the path of the underwater Robot. Experimental results show that the improved method that proved to be practical is superior to the traditional one in the aspect of control time and accuracy.

Design and real-time implementation of actuator fault-tolerant control for differential-drive mobile robots based on multiple-model approach

In this article, an actuator fault-tolerant control scheme is proposed for differential-drive mobile robots based on the concept of multiple-model approach. The nonlinear kinematic model of the differential-drive mobile robot is discretized and a bank of extended Kalman filters is designed to detect, isolate, and identify actuator faults. A fault-tolerant controller is then developed based on the detected fault to accommodate its effect on the trajectory-tracking performance of the mobile robot. Extensive experimental results are presented to demonstrate the efficacy of the proposed fault-tolerant control approach.

Solving the pulley inclusion problem for a cable-driven parallel robotic system: Extended kinematics and twin-pulley mechanism

For a cable-driven parallel robot system, the robot kinematic models usually assume that the cable connection in the system comprises ideal fixed points on the base and an end-effector. However, the cables are usually guided around pulleys, so the pulley geometry can induce movable connection points when operating the robot system. Some previous studies have addressed the influence of the geometry of the guiding pulleys on the parallel cable robot’s kinematics, and extended pulley kinematics have been proposed by considering the pulley radius. However, the inverse kinematics of the extended pulley kinematics may hinder the implementation of an actual system, especially owing to the real-time computation capacity. Hence, in this study, to solve the pulley kinematic inclusion problem for a cabledriven robotic system and to improve the position control performance, we investigated the actual pulley kinematic effect and we proposed two methods for a fully constrained planar cable robot. Comparison and evaluations based on simulations and experiments using the proposed methods in terms of the end-effector posture demonstrated their validity for solving pulley inclusion problems for a cabledriven parallel robot.

Research on Trajectory Tracking Control of Large Intelligent Mower Based on Neural Network

A new large intelligent mowing robot based on four wheeled mobile robot structure is proposed in the paper. Trajectory tracking control is a key factor for high efficiency of mowing robot. Firstly, the kinematics model of the intelligent mowing robot is established by Ackerman model in order to solve the trajectory tracking problem. Subsequently, the trajectory tracking algorithm based on BP neural network is designed, which is used to solve the nonlinear problem of trajectory tracking. Finally, the kinematics model and trajectory tracking algorithm are simulated by MATLAB. The simulation experiment results prove that trajectory tracking algorithm is effective.

Retrofitting of the IRB6-S2 robotic manipulator using Computer Numerical Control- based controllers

This work presents a comparative and descriptive study of numerical control machines solutions using Linux and Windows operating systems, used for the retrofitting of two similar models of old industrial robots, using controllers based on Computer Numerical Control (CNC). Federal University of Minas Gerais (UFMG) and University of Brasilia (UnB) adopted two different softwares, including the robot kinematics model and the generation of joint signal control. Furthermore, this article proposes a comparative study of the two open architecture controllers’ implementation advantages and CAD/CAM integration option, by describing and analyzing each academic solution and choosing the best alternative controller to implement the retrofitting technique for old industrial robots. The comparative study validated the developed generic robot retrofitting methodology, which can be considered as the work’s greatest contribution, as well as providing the open-source project, hardware and software, for ASEA IRB6-S2 Robot retrofitting. The proposed methodology is composed by a set of methods and activities described through an IDEF0 (Icam DEFinition for Function Modeling) model, which can be applied to the retrofitting of any industrial robot with serial or parallel kinematics, which guides the developer in five steps associated with the hardware and software specification for a desired robotic platform implementation as a custom solution based on LinuxCNC system.

Design of a lightweight dual arm system for aerial manipulation

ABSTRACT This paper presents the development and experimental validation of a low weight and inertia, human-size and highly dexterous dual arm system designed for aerial manipulation with multirotor platform. The arms, weighting 1.8 kg in total and with a maximum lift load per arm around 0.75 kg, provide five degrees of freedom (DOF) for end-effector positioning and wrist orientation. A customized aluminum frame structure supports the servo actuators, placing most part of the mass close to the shoulder structure in order to reduce the inertia. A double flange bearing mechanism in side-by-side configuration isolates the servos from impacts and radial/axial overloads, increasing robustness. This is important to prevent that the arms are damaged during physical interactions with the environment, as they should support the kinetic energy of the whole platform. The motivation in the development of a dual arm aerial manipulator is extending the range of applications and tasks that can be performed with respect to the single arm case, like grasping large objects or assembling. The paper covers the kinematic and dynamic modeling of the aerial robot, proposing a control scheme that deals with the technological limitations of the smart servo actuators. The performance of the arms and the interactions with the aerial platform are evaluated in test bench experiments. The proposed dual arm design is validated through outdoor flight tests with two commercial hexarotor platforms equipped with standard industrial autopilots.

Optimization Design by Genetic Algorithm Controller for Trajectory Control of a 3-RRR Parallel Robot

In order to improve the control precision and robustness of the existing proportion integration differentiation (PID) controller of a 3-Revolute–Revolute–Revolute (3-RRR) parallel robot, a variable PID parameter controller optimized by a genetic algorithm controller is proposed in this paper. Firstly, the inverse kinematics model of the 3-RRR parallel robot was established according to the vector method, and the motor conversion matrix was deduced. Then, the error square integral was chosen as the fitness function, and the genetic algorithm controller was designed. Finally, the control precision of the new controller was verified through the simulation model of the 3-RRR planar parallel robot—built in SimMechanics—and the robustness of the new controller was verified by adding interference. The results show that compared with the traditional PID controller, the new controller designed in this paper has better control precision and robustness, which provides the basis for practical application.

CONCERTINA LOCOMOTION OF A SNAKE ROBOT IN THE PIPE

Urgency of the research. Nowadays robotics and mechatronics come to be mainstream. With development in these areas also grow computing fastidiousness. Since there is significant focus on numerical modeling and algorithmization in kinematic and dynamic modeling. Inspection of the pipes is well-known engineering application. For this application are usually used wheel-based robots. Another approaches are based on biologically inspired mechanisms like inchworm robot. Our study deals with another kind of pipe inspection robot, namely snake robot. Target setting. Modeling and testing of snake robot moving in the pipe for the inspection purposes. Actual scientific researches and issues analysis. Pipe inspection is usually done by wheel-based robots. However, snake robots have great potential to do these applications. Uninvestigated parts of general matters defining. Inspection in section of curved pipes is still the actual point of research. The research objective. In the paper the locomotion pattern of namely snake robot is designed and experimentally verified. The statement of basic materials. This paper investigates the area of numerical modeling in software MATLAB. The paper presents locomotion pattern of snake robot moving in the narrow pipe. Next, kinematic model for robot is derived and motion of robot simulated in the software MATLAB. Subsequently the experiments are done with experimental snake robot LocoSnake. In the conclusion the simulation and experiment results are compared and discussed. Conclusions. The paper introduces concertina locomotion pattern of namely snake robot with numerical modeling as well as experimental verification. The results of experiment are different from simulation mainly because of differences of kinematic configuration between simulation and real model. The experiment also shows uniqueness of kinematic configuration using revolute as well as prismatic joints, what is for concertina locomotion significant.

A Method of Robot Base Frame Calibration by Using Dual Quaternion Algebra

When the robot is required to execute a certain task in the world coordinate system (WCS), it is necessary to find the coordinate transformation between the robot base coordinate system (RBCS) and WCS to enable the high precision motion planning. This paper presents a simple and accurate method that allows a simultaneous computation of the coordinate transformations (i.e., rotation and translation) from WCS to RBCS. Based on the dual quaternion, the robot kinematic model and formulas for calculating the transformation are derived, which allow calculating the rotation and translation simultaneously. Taking the unit dual quaternion as a constraint, the Lagrangian multiplier method is employed to obtain the optimum transformation. Both simulation and experiment results show that higher calibration precision is obtained. The proposed approach has certain reference value and guiding sense for other calibration problems.

Bionic Attitude Transformation Combined with Closed Motion for a Free Floating Space Robot

In order to realize the small error attitude transformation of a free floating space robot, a new method of three degrees of freedom(DOF) attitude transformation was proposed for the space robot using a bionic joint. A general kinematic model of the space robot was established based on the law of linear and angular momentum conservation. A combinational joint model was established combined with bionic joint and closed motion. The attitude transformation of planar, two DOF and three DOF is analyzed and simulated by the model, and it is verified that the feasibility of attitude transformation in three DOF space. Finally, the specific scheme of disturbance elimination in attitude transformation is presented and simulation results are obtained. Therefore, the range of application field of the bionic joint model has been expanded.

Leader-Follower Control Strategy with Rigid Body Behavior

Abstract This work presents a control strategy for a leader-follower formation distance-based model of two single order kinematic model of robots. It uses feedback linearization techniques to derive the control action on the follower robot to maintain a desired distance and orientation with respect to the leader robot. Besides, it is shown that a suitable selection of the desired parameters make the formation behave as a rigid body. The control strategy is applied in a laboratory environment with two omnidirectional robots to show its performance.

Kinematics simulation analysis and trajectory planning of a moving robot based on ADAMS

The study of kinematics modeling and simulation of industrial robots is the basis of robot development and optimization. According to the configuration characteristics of a moving robot, the coordinate system and the kinematics equation of the connecting rod are established based on the DH coordinate transformation method. The kinematics positive solution problem is solved in detail. The moving robot is established by the joint simulation of Solid works and ADAMS The motion model of the moving robot is verified by the kinematic analysis, and the displacement and angle curve of the end point are obtained. The rationality of the kinematics model of the moving robot is verified. The trajectory planning of the moving robot is carried out according to the actual situation, the results show that the moving robot is running smoothly and meets the requirements, which provides an important basis for the subsequent control research.

Modeling and experimental evaluation of an improved amphibious robot with compact structure

Abstract This paper describes an improved three-dimensional (3D)-printed, low-cost, multi-functional, high-maneuverability, high-concealment, turtle-inspired mobile amphibious spherical robot for environmental monitoring and data collection. The major challenge in developing such a robot lies in its limited physical size and compact structure that allows for only one type of propulsion system to be used both on land and in water. This paper focuses on the optimization of the kinematic and hydrodynamic model of the amphibious spherical robot, so as to improve the control accuracy and stability of the robot. In order to optimize some kinematic and dynamic modeling parameters of the robot, such as the drag coefficient of robot, the angular velocity and swing angle of each joint, a solid model of the 3D-printed robot was built by SolidWorks. Our simulation results and theoretical calculations confirmed the validity of the virtual model and facilitated identification of key parameters in the design. The correctness of the modeling was demonstrated by the stability of consecutive crawling and underwater movements, providing a basis for driving and controlling methods for this amphibious robot, as well as guidance for the robot's gait trajectory. Combining the robot's crawling mechanism with related simulation results, an optimized prototype of the 3D-printed amphibious spherical robot was constructed. A series of crawling experiments on a common floor were performed with the improved robot prototype, which was also done using the previous robot. The results were evaluated by a novel optical positioning system, NDI Polaris. Moreover, several experiments were carried on land crawling and underwater swimming to verify the performance of the improved amphibious spherical robot. Comparison of experimental and simulation results demonstrated the improved robot had better amphibious motion performance, as well as more potentiality and applicability to the real structures.

Modeling and calibration of high-order joint-dependent kinematic errors for industrial robots

Abstract Robot positioning accuracy is critically important in many manufacturing applications. While geometric errors such as imprecise link length and assembly misalignment dominate positioning errors in industrial robots, significant errors also arise from non-uniformities in bearing systems and strain wave gearings. These errors are characteristically more complicated than the fixed geometric errors in link lengths and assembly. Typical robot calibration methods only consider constant kinematic errors, thus, neglecting complex kinematic errors and limiting the accuracy to which robots can be calibrated. In contrast to typical calibration methods, this paper considers models containing both constant and joint-dependent kinematic errors. Constituent robot kinematic error sources are identified and kinematic error models are classified for each error source. The constituent models are generalized into a single robot kinematic error model with both constant and high-order joint-dependent error terms. Maximum likelihood estimation is utilized to identify error model parameters using measurements obtained over the measurable joint space by a laser tracker. Experiments comparing the proposed and traditional calibration methods implemented on a FANUC LR Mate 200i robot are presented and analyzed. While the traditional constant kinematic error model describes 79.4% of the measured error, the proposed modeling framework, constructed from measurements of 250 poses, describes 97.0% of the measured error. The results demonstrate that nearly 20% of the kinematic error in this study can be attributed to complex, joint-dependent error sources.

Sensitivity Analysis and Model Validation of a 2-DoF Mini Spherical Robot

This paper is focused on the development and validation of an error kinematic model of a mini spherical robot, aimed at its kinematic calibration. The robot is actually a spatial five-bar linkage, provided with two rotational degrees of freedom. A non-overconstrained kinematics is assumed for the robot in order to provide a simple mathematical model and allow a sensitivity analysis of all the involved geometric parameters. A simplified version of the model is proposed. It differs only for the degree of approximation. A comparison between full and reduced models is presented by means of numerical simulations, analyzing their behavior in a significant region of the robot workspace. In order to validate both of them a robot calibration is carried out on a physical prototype of the robot using a vision system, namely a fixed camera in a eye-to-hand configuration. An iterative algorithm aimed at the experimental identification of the geometric data of the robot is used. Some experimental results show the effectiveness of the study.

Accurate Task-Space Tracking for Humanoids with Modeling Errors Using Iterative Learning Control

Precise task-space tracking with manipulator-type systems requires an accurate kinematic model. In contrast to traditional manipulators, sometimes it is difficult to obtain an accurate kinematic model of humanoid robots due to complex structure and link flexibility. Also, prolonged use of the robot will lead to some parts wearing out or being replaced with a slightly different alignment, thus throwing off the initial calibration. Therefore, there is a need to develop a control algorithm that can compensate for the modeling errors and quickly retune itself, if needed, taking into account the controller bandwidth limitations and high dimensionality of the system. In this paper, we develop an iterative learning control algorithm that can work with existing inverse kinematics solvers to refine the joint-level control commands to enable precise tracking in the task space. We demonstrate the efficacy of the algorithm on a theme-park-type humanoid doing a drawing task, serving drink in a glass, and serving a drink placed on a tray without spilling. The iterative learning control algorithm is able to reduce the tracking error by at least two orders of magnitude in less than 20 trials.

A Guiding Vector-Field Algorithm for Path-Following Control of Nonholonomic Mobile Robots

In this paper, we propose an algorithm for path-following control of the nonholonomic mobile robot based on the idea of the guiding vector field (GVF). The desired path may be an arbitrary smooth curve in its implicit form, that is, a level set of a predefined smooth function. Using this function and the robot's kinematic model, we design a GVF, whose integral curves converge to the trajectory. A nonlinear motion controller is then proposed, which steers the robot along such an integral curve, bringing it to the desired path. We establish global convergence conditions for our algorithm and demonstrate its applicability and performance by experiments with wheeled robots.

Simulation and Analysis of the Movement of a Group of Mobile Robots in ROS

The paper presents a simulation of a group movement of mobile robots in absence of obstacles in ROS and a kinematics model of the mobile robots used in the simulation. Three types of motion behavior of the mobile robots in a group were considered. First, the authors achieved a synchronization of the mobile robots in a group using the centralized method, which requires a control center, and the decentralized method, in which the mobile robots in a group communicate with each other. Second, the authors simulated movement of four mobile robots in Zhukov forms, when each robot was controlled according to the relative position of the two neighboring robots. Different trajectories of the mobile robots were obtained depending on the selected control parameters. The authors analyzed the relation between the control parameters and the resulting trajectories. Finally, the authors simulated movement of a group of the mobile robots in a convoy type of formation. Three different control algorithms were considered. The authors analyzed and compared the trajectories of the mobile robots moving in the convoy type of formation using three different control algorithms. The advantages and disadvantages of the three control algorithms were presented. The authors discussed a range of problems, which could be encountered when conducting physical experiments, for example, communication between the robots, the process of localization of the mobile robots in a group, and the impact of a sensor noise.