Recursive Newton-Euler Method Research Articles

Dynamic Analysis and Control of Redundant Manipulator for Agricultural Applications in a Virtual Environment

In the development of automated manipulators for fruit and vegetable picking technologies, the challenge of ensuring an efficient, stable, and loss-free picking process has been a complex problem. In such an environment, manipulators require the most efficient and robust control for effective operations. In this paper, a serial 9-DOF redundant manipulator (1P8R) is proposed with various controllers for trajectory tracking problems in agricultural applications. The dynamic analysis of redundant manipulator has been carried out using the Recursive Newton-Euler method. The joint configurations of the robot are determined using optimization techniques for specific Task Space Locations (TSLs) by avoiding obstacles. The process of generating joint trajectories has been implemented by considering the cubic polynomial function. For the task of controlling the robot trajectory tracking in the virtual agricultural environment, different combinations of Proportional (P), Integrative (I), Derivative (D), and Feed-Forward (FF) controllers are employed, and a comparative analysis has been performed among these controllers. To verify the performance of the manipulator, simulations are carried out in a virtual environment using Simulink software. Results show that the robot is able to reach specific TSL accurately with better control and it is found that the implementation of Feed-Forward and PID-CTC controllers has better performance in a complex environment.

Modeling and Simulation of an Octorotor UAV with Manipulator Arm

In this paper, the conceptual design, modeling, and simulation are proposed for an octorotor UAV with a manipulator arm. The conceptual design of the octorotor UAV with a manipulator arm is developed, and for the study and analysis, the design is implemented and validated in Matlab (Simulink-SimMechanics) software. The kinematics and dynamics models of the octorotor UAV with a manipulator arm are obtained using the classical Denavit–Hartenberg convention and the recursive Newton–Euler method, respectively. In this sense, a cascade PID controller for the attitude and navigation of the UAV and a simple PID controller for the manipulator arm are proposed and simulated in a closed-loop system in order to highlight the performance of the proposed design. Finally, simulations show the feasibility and behavior of the mathematical model and the flight controller in a closed-loop system.

Dynamic analysis of a three-fingered deployable metamorphic robotic grasper

This paper selects a three-fingered deployable metamorphic robotic grasper as the studied object and presents a distributed dynamic modeling method for the multi-body system based on the metamorphic mechanism. Considering that the grasper contains two independent motion configurations, dynamic models of them are independently established, and then the final dynamic model of the whole grasper is formed. To further improve the modeling accuracy, it is creatively proposed that irregular links can be seen as rigid connections of multiple regular links, by which the dynamic model for the deployment motion of the grasper is firstly established via the Lagrange equation. For the grasping motion, since the finger of the grasper can be equivalent to a planar 4R serial mechanism, the dynamic models of the base mechanism and the basic module are established by the Lagrange equation to obtain the relationships between the driving forces and the equivalent torques. The whole grasper is then established by the recursive Newton-Euler method to enhance the modeling efficiency. Finally, the effectiveness of the dynamic model is well verified by the dynamic simulation.

A Recursive Dynamic Modeling and Control for Dual-arm Manipulator With Elastic Joints

A recursive dynamic modeling and control is presented for the dual-arm manipulator with elastic joints carrying a common object. For decoupling the effect of elastic joints, the dynamic modeling approach is based on the classic recursive Newton-Euler method but involves high-order derivatives of motion and force variables. The high-order inverse kinematics which is needed in the motion control is presented firstly. With the classic Recursive Newton-Euler (RNEA) method, two-order dynamic model of the dual-arm robot is established, for decoupling the effect of the elastic joints, the form of four-order dynamic model is presented, meanwhile, combining with the high-order dynamic model of the carried object, the completed Dual-Arm Elastic Joints Newton-Euler Algorithm (DA-EJNEA) is established. Then the feedback linearization method is adopted to the motion control based on the DA-EJNEA. Finally, to verify the effectiveness of the proposed method, feedback linearization method based on the DA-EJNEA and the computed torque method based on the dynamic model with rigid joints are used to control the dual-arm coordinated system respectively, the simulation results illustrate the feedback linearization method based on the DA-EJNEA has an obvious advantage for trajectory tracking of the object in the operation space, it behaves reasonable potentials for the model-based control.

Dynamic Modeling and Control for a Deployable Grasping Manipulator

This paper presents a special type of truss-shaped deployable grasping manipulator (DGM) that is suitable for grasping the large-scale objects, but its dynamic modeling is a challenging task because of its multiple closed-loop structures. To address this issue, an iterative dynamic modeling approach is proposed. First, the mechanism structure of the DGM is introduced. Second, the kinematics of the basic deployable parallel mechanism unit with scissor-shaped elements is established, and then, its deployment dynamics are modeled based on the Lagrange method. Third, an iterative dynamic modeling approach for the DGM is proposed to realize the real-time computation based on the recursive Newton-Euler method. Then, a controller with the desired feedforward dynamic compensation for the DGM is proposed to improve the control performance in comparison with the one without feedforward. Finally, experiments are completed to verify the proposed controller on a DGM, and experimental results show that the proposed controller is effective.

Adaptive Visual Tracking Control for Manipulator With Actuator Fuzzy Dead-Zone Constraint and Unmodeled Dynamic

This paper focuses on a problem of adaptive visual tracking control for an uncalibrated image-based visual servoing manipulator system with actuator fuzzy dead-zone constrain and unknown dynamic. Without a prior knowledge of the system, fuzzy logic systems are employed to approximate the unmodeled nonlinear manipulator dynamics and external disturbances. By using the recursive Newton–Euler method, the total number of fuzzy rules can be reduced significantly as compared with the traditional fuzzy logic system. By defuzzifying the fuzzy slope $\tilde {k}$ of the fuzzy dead-zone model to a deterministic value $\bar {k}$ , a novel fuzzy adaptive controller is constructed to eliminate the harmful effect of fuzzy dead-zone constrain. Lyapunov functions are presented for stability analysis of visual feedback control problem with unknown dynamics and actuator fuzzy dead-zone constrains. Experimental results are carried out to test the visual tracking performance of the proposed controller and the boundedness of the closed-loop system.

Complexity Analysis for Calculating the Jacobian Matrix of 6DOF Reconfigurable Machines

The Jacobian matrix for machinery systems is challenging due to the kinematic structure, the machine behaviour, the machine configurations, and the singularity conditions. In the area of singularity, small velocities in the operational space may result in large velocities in the joint space. Therefore the control processes of machines may sometimes run into difficulties, since the inverse mapping from a Cartesian space to a joint space may cause problems. For solving the singularity of the kinematic structure, the development of the Jacobian matrix is the first priority. All of the different methods used for the Jacobian calculation are complex and require mathematical tools for symbolic calculation. It is important to select the most appropriate method with the minimum complexity for quick and accurate Jacobian matrix calculation. Thus, the authors were motivated to choose different procedures for developing the Jacobian matrix. In this study, the most general reconfigurable machinery kinematic structure, a remodelled n-DOF Global Kinematic Model, CNC-R GKM, is selected for the Jacobian matrix computation analysis. Each joint represents a combination of either rotational and/or translational joints type with any joint positive direction, with total number of 36 possible configurations in one joint. Calculation of the Jacobian matrix for this highly complex reconfigurable kinematic model, gives a comprehensive and unique results. The selected methods for Jacobian calculation are recursive Newton-Euler method and Vector cross multiplication method. The symbolic mathematical tool MAPLE 16 has been used. The comparison between these two calculation procedures has been completed with respect to the calculation complexity, and the results have been validated using the new developed CNC-Robot Global Kinematic Model (CNC-R GKM). The kinematic model and Jacobian matrix calculation used in this study are applicable in reconfigurable robotic and machines in industry, space and health care.

Dynamic analysis of the upper limb during activities of daily living: Comparison of methodologies

Often researchers use kinematics and kinetics to evaluate the effect of limb pathology. The net forces and moments that cause motion depend on kinematics, body segment parameters and the external loads applied. This study aimed to evaluate the discrepancies caused by different methods and assumptions of kinetic analysis. Dynamic analysis was performed on 12 subjects with no known pathology while performing 12 activities of daily living. The recursive Newton-Euler method, along with two robotic models containing 7 and 14 degrees of freedom representing the upper limb, was used to calculate the net forces and moments across the shoulder. The data were calculated using different body segment parameter values from the literature and, in order to concentrate on the effects of kinematics only, these results were presented as both a percentage of the body weight and a novel technique using constant body segment parameter. The greatest net forces and moments on the glenohumeral joint were observed for lifting a 2-kg shopping bag task (forces: 60 ± 8 N and moments: 18 ± 2 N m) and the lowest was observed for drinking (forces: 40 ± 8 N and moments: 6 ± 1 N m). Overall, the results from different techniques (recursive Newton-Euler vs robotic 14 degrees of freedom) were similar, while the 7-DoF model showed less agreement. The use of different body segment parameter values resulted in a maximum increase of 25% in the glenohumeral moment. Following normalisation of the body segment parameter, dynamic parameters were found to have less variation. In order to focus on the effect of variation in movement in dynamic study, it is therefore necessary to normalise the body segment parameter.

The effect of base replacement on the dynamic load carrying capacity of robotic manipulators

The problem of establishing the load carrying capacity of mobile base manipulators operated by limited force or torque actuators is presented. It is shown the maximum allowable load on a given load trajectory, is a function of base position. The load workspace is defined as the union of places where the base can be located on them and it carries a load by the manipulator on a desired trajectory. The load workspace is discretised into some grid points, and the base is positioned on each grid point. The recursive Newton-Euler method is used to compute the dynamic effects of the load and manipulator on each joint actuator, then the load carrying capacity of the mobile manipulator at each base location is computed by considering the manipulator joints and actuator torque constraints. By applying a simple procedure, a smaller subspace of the load workspace is selected, so that the load carrying capacity is near to a maximum. This procedure is repeated until the optimum base location is found so that the load carrying of the manipulator is a global maximum in the load workspace for the desired dynamic trajectory. Finally, the effect of base mobility on optimising the dynamic load carrying capacity for different robotic arms is investigated in separate case studies.

An approach to validation of a leg simulation by the comparison of two dynamic models

The dynamics of a jointed leg were simulated using two different models, one based on a recursive Newton-Euler method and one on a closed-form Lagrange method. To validate the models, the simulations were run in parallel and the intermediate steps and output of the two methods were compared to one another to reveal the presence and locations of errors. Sources of error and the use of this method for the detection of errors are discussed. Some errors could not have been detected using only a single simulation.