Movement Of Manipulator Research Articles

Simulation and Analysis of a Kind of Cam Manipulator Based on Rigid Flexible Coupling Dynamics Theory

Based on the theory of rigid flexible coupling, a cam manipulator used in an automatic production line is simulated. By comparing the differences between rigid body system and rigid flexible coupling system in various dynamic performance indexes, it can be seen that the positioning accuracy and stability of manipulator movement are affected by the elasticity of components. In the case of high accuracy requirements, the elasticity of members cannot be ignored. The simulation analysis provides the basis for the following optimization design and machining.

Improved Manipulator Obstacle Avoidance Path Planning Based on Potential Field Method

Aiming at the existing artificial potential field method, it still has the defects of easy to fall into local extremum, low success rate and unsatisfactory path when solving the problem of obstacle avoidance path planning of manipulator. An improved method for avoiding obstacle path of manipulator is proposed. First, the manipulator is subjected to invisible obstacle processing to reduce the possibility of its own collision. Second, establish dynamic virtual target points to enhance the predictive ability of the manipulator to the road ahead. Then, the artificial potential field method is used to guide the manipulator movement. When the manipulator is in a local extreme or oscillating, the extreme point jump-out function is used in real time to make the end point of the manipulator produce small displacements and change the action direction to effectively jump out of the dilemma. Finally, the manipulator is controlled to avoid all obstacles and move smoothly to form a spatial optimization path from the start point to the end point. The simulation experiment shows that the proposed method is more suitable for complex working environment and effectively improves the success rate of manipulator path planning, which provides a reference for further developing the application of manipulator in complex environment.

Emergency Braking Trajectory Control for Manipulator in the Case of Driver Failure

In emergency situation robot control system stops the manipulator by shutdowning drivers and activating brakes. This mode is used in all cases of equipment failure detection or while alarm bottom is pressed on control panel. Emergency braking is uncontrolled motion. As result manipulator movement deviates from program trajectory as the relations between velocities in joints differ significantly. This creates danger of collisions with objects in robot work space. The paper describes device that can be connected to control system. Connection needs insignificant changing in hardware architecture of robot control system. Device consists of controller and individual electronic schemes that are able to activate brakes of each degree of freedom regardless from other one. This feature allows to design braking trajectory by activating brakes in specific sequence and calculated delays. Mathematical solution for deviation minimization problem of braking trajectory from program one is presented. The solution is reduced to mathematical formulas which depend of the temporary velocities and values of braking decelerations in manipulator joints. The considered way of control differs from similar one described earlier by that in emergency situation drivers turn off immediately. On the first stage manipulator brakes by friction forces in gear boxes. Theoretical evaluations show that in all cases this reduces deviations from program trajectory. Additionally the new way can be used even if fault takes place at least one of drivers.

Real-Time Joint Angular-Acceleration Planning for Vision-Based Kinematically Redundant Manipulator in Dynamic Environment

This paper presents an angular acceleration planning for joint configuration spaces of vision-based kinematically redundant robot manipulators to achieve real-time tracking tasks in dynamic environment. In accordance with the proved proposition, the joint velocity formed by the inverse kinematics mapping of the defined pose error is regarded as the system error, and utilized to further deduce the planned joint angular acceleration and with kinematic redundancy for obstacle avoidance simultaneously. Highly-complex nonlinearities in the angular acceleration are equivalent to a system perturbation represented by a synthetic form, thereby simplifying the tedious calculations of the angular acceleration theoretically and converting the planning problem into a control problem. Hyperbolic tangent-based super twisting algorithm, as the control input of manipulator system, is designed to resist the synthetic perturbation. The collision-free movement of redundant manipulators for tracking tasks is thus achieved through the integration of the control input in real time. An error-based S-function is proposed as the internal parameter of the planned joint acceleration to prevent the integral saturation. Lyapunov theoretical analysis proves the stability of the proposed super twisting algorithm. Simulation and contrast experiments in dynamic-obstacles environments indicate that the proposed joint angular acceleration planning for kinematically redundant manipulators owns feasibility, smoothness and practicability.

Моделирование влияния возмущающих воздействий на стабильность воздушной манипуляционной системы в программе UAVManipulatorModeling

The paper discusses the scientific problem of controlling an air manipulation system and describes the experimental results of modeling the influence of disturbing influences on the stability of the manipulator movement with 3 degrees of freedom in the developed software system UAVManipulatorModeling.

Design and Implementation of Low Cost Manipulator Robot for Underwater Object Grasping Process

Various developments in the technologies over the industrial sectors, Robots are implemented to perform the several processes like picking and placing objects by using a human hand like structures. These robotic manipulators are mainly employed in the areas which are radioactive or hazardous or the place not accessible by the humans. It uses both direct pneumatics and inverse pneumatics. Underwater object or material grasping is a challenging task in these days. Here we are going to design and implement the robot manipulator at low-cost for object grasping process. The 3 DOF underwater robot manipulator can be developed by using the servo motors embedded in a mechanical setup. A camera based system is used to identify the objects to be grasped. These whole processes can be controlled by using Raspberry pi 3 as a central processor. The movement of the robot manipulator is controlled by using position control joystick through Internet of Things (IoT).

Discrete Model for the Movement of Industrial Manipulator Used in Hot Rolling Process

Discrete Model for the Movement of Industrial Manipulator Used in Hot Rolling Process

Weighted multiple model adaptive boundary control for a flexible manipulator.

In this article, a weighted multiple model adaptive boundary control scheme is proposed for a flexible manipulator with unknown large parameter uncertainties. First, the uncertainties are approximatively covered by a finite number of constant models. Second, based on Euler-Bernoulli beam theory and Hamilton principle, the distributed parameter model of the flexible manipulator is constructed in terms of partial differential equation for each local constant model. Correspondingly, local boundary controllers are designed to control the manipulator movement and suppress its vibration for each partial differential equation model, which are based on Lyapunov stability theory. Then, a novel weighted multiple model adaptive control strategy is developed based on an improved weighting algorithm. The stability of the overall closed-loop system is ensured by virtual equivalent system theory. Finally, numerical simulations are provided to illustrate the feasibility and effectiveness of the proposed control strategy.

Mathematical model of hydromanipulator of forest vehicle with recuperative hydraulic drive

The relevance of using a recuperative hydraulic drive to control the hydraulic manipulator of a timber truck used in conducting selective sanitary cutting of forest care has been substantiated. A mathematical model of the mechanical subsystem of a hydraulic manipulator with a regenerative hydraulic actuator is presented, which describes the movement of a hydraulic manipulator with an assortment in space. Successive states of boom, handle and column of hydraulic manipulator during loading of grades into body of forest truck at different moments of computer experiment time are considered. The research results obtained on the basis of the developed computer program are described.

Fuzzy Torque Control of the Bionic Flexible Manipulator Actuated by Pneumatic Muscle Actuators

A bionic flexible manipulator driven by pneumatic muscle actuator (PMA) can better reflect the flexibility of the mechanism. Current research on PMA mainly focuses on the modeling and control strategy of the pneumatic manipulator system. Compared with traditional electro-hydraulic actuators, the structure of PMA is simple but possesses strong nonlinearity and flexibility, which leads to the difficulty in improving the control accuracy. In this paper, the configuration design of a bionic flexible manipulator is performed by human physiological map, the kinematic model of the mechanism is established, and the dynamics is analyzed by Lagrange method. A fuzzy torque control algorithm is designed based on the computed torque method, where the fuzzy control theory is applied. The hardware experimental system is established. Through the co-simulation contrast test on MATLAB and ADAMS, it is found that the fuzzy torque control algorithm has better tracking performance and higher tracking accuracy than the computed torque method, and is applied to the entity control test. The experimental results show that the fuzzy torque algorithm can better control the trajectory tracking movement of the bionic flexible manipulator. This research proposes a fuzzy torque control algorithm which can compensate the error more effectively, and possesses the preferred trajectory tracking performance.

Вертикальное перемещение рабочей платформы манипулятора

Вертикальное перемещение рабочей платформы манипулятора

Curvature and force measurement of soft manipulator based on stretchable helical optic fibre

Abstract The soft surgical manipulator is a scientific frontier in the fields of minimally invasive surgery and robotics, and it is crucial for improving the performance of surgery. However, owing to its narrow and confined environment in minimally invasive surgeries, some existing methods have not solved its problem of accurate measurement, which limits its application. This paper demonstrates the curvature and force measurement of a hyper-elastic soft manipulator with helically embedded stretchable fibre Bragg grating (FBG)-based fibre optic sensor. Unlike a straight FBG embedding configuration, this unique helical configuration prevents sensor dislocation, supports stretchability, and facilitates the detection of various movements of the soft manipulator. First, the design of the soft manipulator embedded with a stretchable helical optic fibre is described. Second, the sensing theory of the soft manipulator was analysed, and the stretchable helical FBG sensing model was established. Finally, to verify the effectiveness of this design and sensing technique based on the stretchable helical optic fibre, some compression and bending experiments of the soft manipulator were conducted. The results showed that the errors between theoretical and experimental measurements are less than 5%, and the helical structure enables 10% of compression in length, thus facilitating in the measurement of tension and bending curvature of the soft manipulator.

Bio-inspired motion planning for reaching movement of a manipulator based on intrinsic tau jerk guidance

This study proposed a bio-inspired motion planning approach for the reaching movement of a robot manipulator based on a novel intrinsic tau jerk guidance strategy, which was established by some cognitive science researchers when they studied motion patterns through biology. In accordance with the rules of human reaching movement, the intrinsic tau jerk guidance strategy ensures continuity of the acceleration; further, it also ensures that its value is zero at the start and end of the movement. The approach has been implemented on a three-degrees-of-freedom 3R planar manipulator. The results show that, within a defined time, both the position gap and attitude gap can be reposefully closed, and the curves of joint velocity, acceleration, and driving torque are continuous and smooth. According to the dynamic analysis, the proposed approach tends to consume less energy. The bio-inspired method has the potential to be applied in particular scenarios in the future, such as a mobile robot with a manipulator exploring an unknown environment.

Travelling salesman problem concerning to manipulator Kawasaki FS03N trajectory formation

An idea of travelling salesman problem (TSP) application to an optimal manipulator path finding was implemented. A set of known poses robot should pass is given. The poses sequence may vary. A traveling time is a performance criteria to be minimized. This task was realized concerning to a special case of Kawasaki FS03N manipulator movement by dynamic programming method. A special Bellman function state notation was used that in some cases gives an ability to solve the task at industrial robot controller. The state notation rule is one-one mapping rule between TSP state and array index it is stored.

A Vision-Based Coordinated Motion Scheme for Dual-Arm Robots

With the rise of service robots, research on cooperation between two-arm robots has become increasingly important. In this paper, two NAO two-armed robots are used as the experimental platform and are combined with projective geometry, vision, robotics and other knowledge to carry out theoretical derivation and experiments on the coordinated movements of dual-arm robots. From the aspect of visual information processing, we analyse and solve the detailed target recognition process. Then, on this basis, we propose a set of complete coordinated motion control schemes. For object recognition, in this paper, we propose a highly adaptable linear stick recognition method. To solve the control flow of coordinated movement, we calculate the inverse kinematics of the unreachable pose of a single NAO manipulator by ignoring the degree of freedom of rotation around an end axis, and propose a trajectory planning method for the vertical constraint relationship between the tool and the workpiece plane in the coordinated manipulator movement. A comparison of the results of a simulation and a real experiment reveals that the trajectories of a workpiece clamped at the ends of the two robots’ mechanical arms are roughly the same; consequently, the coordinated control scheme proposed in this paper is feasible. Moreover, the scheme proposed in this paper is sufficiently accurate to meet service robot applications in daily life. Because the joint active clearance of the NAO robot arm is large and its sensor sensitivity is high, clearance change can be used in the future to replace the force sensor for hybrid control.

A manipulator control in an unknown environment

An algorithm for a n-link manipulator movement amidst unknown static obstacles in a continuous space is presented. Given theorem stating that if the manipulator moves according to the algorithm will be discovered in a finite number of steps whether a given target configuration is reachable or not. The number, shapes and dispositions of obstacles may be arbitrary.

Development of Robot Platform for Autonomous Underwater Intervention

KRISO (Korea Research Institute of Ship & Ocean Engineering) started a project to develop the core algorithms for autonomous intervention using an underwater robot in 2017. This paper introduces the development of the robot platform for the core algorithms, which is an ROV (Remotely Operated Vehicle) type with one 7-function manipulator. Before the detailed design of the robot platform, the 7E-MINI arm of the ECA Group was selected as the manipulator. It is an electrical type, with a weight of 51 kg in air (30 kg in water) and a full reach of 1.4 m. To design a platform with a small size and light weight to fit in a water tank, the medium-size manipulator was placed on the center of platform, and the structural analysis of the body frame was conducted by ABAQUS. The robot had an IMU (Inertial Measurement Unit), a DVL (Doppler Velocity Log), and a depth sensor for measuring the underwater position and attitude. To control the robot motion, eight thrusters were installed, four for vertical and the rest for horizontal motion. The operation system was composed of an on-board control station and operation S/W. The former included devices such as a 300 VDC power supplier, Fiber-Optic (F/O) to Ethernet communication converter, and main control PC. The latter was developed using an ROS (Robot Operation System) based on Linux. The basic performance of the manufactured robot platform was verified through a water tank test, where the robot was manually operated using a joystick, and the robot motion and attitude variation that resulted from the manipulator movement were closely observed.

Efficient Control of a Non-Linear System Using a Modified Sliding Mode Control

Trajectory tracking is an essential requirement in robot manipulator movement and localization applications. It is a current research topic of interest, and several researchers have proposed different schemes to achieve the task accurately. This research proposes efficient control of a hydraulic non-linear robot manipulator using a modified sliding mode control, named proportional derivative sliding mode control with sliding perturbation observer (PDSMCSPO), to overcome parameter uncertainties and non-linearity. The proposed new control strategy achieves higher accuracy and better time convergence than the previous one. A positive derivative gain, which has a value less than one, is multiplied with the velocity error term of the sliding surface. The proposed control (PDSMCSPO) also achieves robustness. Results show that by introducing the derivative gain, the chattering from the system has been reduced more than classical sliding mode control (SMC). The reason is that during reaching phase this small gain multiplies with the perturbation and minimizes the effect of perturbation on the system. A smaller value of switching gain K is required as compared to SMC, and the transfer function between sliding surface and perturbation in proportional derivative sliding mode control (PDSMC)has low pass filter characteristics. The proposed PDSMCSPO has a faster response than previous sliding mode control with sliding perturbation observer (SMCSPO), and the output and sliding surface convergence to the desired value is much quicker than conventional logic. Some other characteristics such as error in the output are small because of more attenuation of the perturbation signal. Simulation and experimental results are presented for a link between the hydraulic robot manipulator and the mass damper system.

Optimal cascaded control of mobile manipulators

In this study, the solution to the kinematically optimal control problem of the mobile manipulators is proposed. Both dynamic equations are assumed to be uncertain, and globally unbounded disturbances are allowed to act on the mobile manipulator when tracking the trajectory by the end effector. We propose a computationally efficient class of cascaded control algorithms, which are based on an extended Jacobian transpose matrix. Our controllers involve two new non-singular terminal sliding mode manifolds defined by nonlinear integral equalities of both the second order with respect to the task space tracking error and the first order with respect to reduced mobile manipulator acceleration. Using the Lyapunov stability theory, we prove that the proposed Jacobian transpose cascaded control schemes are finite time stable provided that some practically reasonable assumptions are fulfilled during the mobile manipulator movement. The numerical examples carried out for mobile manipulators [consisting of a non-holonomic platform of type (2, 0) and holonomic manipulators of 2 and 3 revolute kinematic pairs], which operate in two-dimensional and three-dimensional work spaces, respectively, illustrate both the trajectory tracking performance of the proposed control schemes and simultaneously their minimising property for some practically useful objective function.

Synthesis of Optimal Dynamic Mode of Manipulator Boom Movement Mounted on Elastic Base

In order to increase reliability and accuracy of robot manipulators or other construction equipment used for lifting operations an optimum dynamic mode for moving its boom system has been calculated in the paper. Results of the research have made it possible to construct a mathematical model for manipulator movement and obtain kinematic characteristics of the optimum dynamic mode. While determining the optimum dynamic motion mode, a criterion action has been used as an optimization criterion which represents a time integral with an integrand function expressing a dynamic component of manipulator drive power. Functions for changing kinematic characteristics of an manipulator boom have been calculated when it moves from one predetermined position to another one and which correspond to optimum dynamic mode of motion. Search for an optimum motion mode has been performed by minimizing the optimization criterion using the Euler–Poisson equations. In this case a generalized angle of rotation has been used which permits to relate movement of the boom and oscillations of its support part. As a linking component differential equations of system motion have been also applied, in which relationships between an oscillation angle, rigidity of a manipulator support, and its mass-geometric characteristics have been recorded. Results of the work can be useful for refinement and improvement of existing engineering methods for calculating the drive mechanisms of manipulators both at design/construction stages and in real operation modes, and the results can also be used while making design or improvement of similar executive mechanisms for construction equipment and robots.