Dynamic Modeling and Analysis of a Fruit and Vegetable Picking Robot

2012 ◽  
Vol 241-244 ◽  
pp. 1845-1849
Author(s):  
Yan Wang ◽  
Yun Wang Ge ◽  
Xiao Li Wang
Keyword(s):  
Dynamic Modeling ◽  
Trajectory Planning ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Angular Displacement ◽  
Fruit And Vegetable ◽  
Robot System ◽  
Modeling And Analysis ◽  
Abrupt Changes ◽  
Simulation Results

According to characteristics of the fruit and vegetable picking operations, an articulated picking robot with four degree-of-freedom is developed. And in order to perform an expected motion of picking work, the kinematic and dynamic models have to be constructed firstly. Kinematics is established based on Denavit-Hartenberg notation. Then, the explicit expressions of dynamic models are presented through Lagrange equation. Finally, trajectory planning from one point to another point is carried out with cycloidal motion, and the angular displacement, velocity, acceleration and torque curves of each joint are analyzed. Simulation results show that the torque curves are quite smooth and with no abrupt changes, which indicates that the motions of each joint won’t result vibrations and can ensure stability of the robot system.

Pseudo-rigid-body dynamic modeling and analysis of compliant mechanisms

2017 ◽  
Vol 232 (9) ◽  
pp. 1665-1678 ◽  
Author(s):  
Yue-Qing Yu ◽  
Qian Li ◽  
Qi-Ping Xu
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Dynamic Models ◽  
Compliant Mechanisms ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Modeling And Analysis ◽  
Rigid Body Dynamic ◽  
Body Dynamic

An intensive study on the dynamic modeling and analysis of compliant mechanisms is presented in this paper based on the pseudo-rigid-body model. The pseudo-rigid-body dynamic model with single degree-of-freedom is proposed at first and the dynamic equation of the 1R pseudo-rigid-body dynamic model for a flexural beam is presented briefly. The pseudo-rigid-body dynamic models with multi-degrees-of-freedom are then derived in detail. The dynamic equations of the 2R pseudo-rigid-body dynamic model and 3R pseudo-rigid-body dynamic model for the flexural beams are obtained using Lagrange equation. Numerical investigations on the natural frequencies and dynamic responses of the three pseudo-rigid-body dynamic models are made. The effectiveness and superiority of the pseudo-rigid-body dynamic model has been shown by comparing with the finite element analysis method. An example of a compliant parallel-guiding mechanism is presented to investigate the dynamic behavior of the mechanism using the 2R pseudo-rigid-body dynamic model.

scholarly journals Dynamics Modeling and Analysis of a Novel Constraint Metamorphic Reversible Plough

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Yanyan Song ◽  
Boyan Chang ◽  
Guoguang Jin ◽  
Zhan Wei ◽  
Bo Li
Keyword(s):  
Closed Loop ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Initial Position ◽  
Dynamics Modeling ◽  
Constraint Force ◽  
Vector Method ◽  
Modeling And Analysis ◽  
Acceleration Analysis ◽  
Source Phase

To meet the requirements of different farming objects, this paper presents a novel constraint metamorphic reversible plough (CMRP) which has four distinct working phases and the feature of underactuation, and its prototype has been manufactured for practical testing purposes. Firstly, the kinematics of the mechanism in each phase are studied systematically with the closed-loop vector method, including displacement, velocity, and acceleration analysis. Considering the underactuated characteristics of the mechanism in the source phase, its dynamic models in the source phase are further established by the Lagrange equation. Based on the theory that velocity and acceleration are the same in an extremely brief period, the motion laws of the slider in the source phase can be obtained. To obtain the constraint force/torque acting on the crucial joints in each phase, the dynamic model of the CMRP is established by the Newton–Euler equation. Furthermore, the initial position of the CMRP with a flexible prismatic joint can be determined using the static balance equation. Finally, the obtained kinematic and dynamic models of the CMRP in each phase are verified, respectively, through comparing the simulation results in SolidWorks and Matlab software, and the experiment with the prototype is conducted. The CMRP proposed in this study provides a feasible technical scheme for improving the capability of reversible plough over unknown and complex terrains.

scholarly journals Dynamic Modeling, Response, and Chaos Analysis of 2-DOF Hybrid Mechanism with Revolute Clearances

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Xiulong Chen ◽  
Yuefei Tang
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Modeling And Analysis ◽  
Hybrid Mechanism ◽  
Nonlinear Dynamic Models ◽  
Collision Force

Due to the errors arising from machining or assembly, the deformation during movement, and the wear of movement pairs, the clearance will be generated at the kinematic pair of the mechanism, and the service life or working accuracy of the mechanism is reduced. At present, most of the researches are in a simple mechanism with a single clearance, and there are few papers on the complex mechanism, such as the high-speed mechanism which contains multiple clearances. In order to give a computational methodology for the dynamic modeling and analysis of the planar multilink mechanism with multiple degrees of freedom and multiple clearances and master the dynamic characteristics of the planar multilink mechanism, the nonlinear dynamic models of the multiclearance hybrid seven-bar mechanism under different clearance numbers, different clearance values, different clearance positions, and different driving velocities are established and analyzed. The dynamic output response comparison diagram of the mechanism and the collision force diagrams and center trajectory diagrams of the mechanism at the clearance are given. Then, nonlinear dynamics of the mechanism is studied by different clearance values and driving speeds. The corresponding trajectory phase diagrams, Poincare maps, and bifurcation diagrams are given. The above research results provide an effective theoretical basis for the study about the nonlinear dynamic characteristics of the planar link mechanism with clearance and how to compensate or control the clearances.

scholarly journals Dynamic Modeling and Analysis of the Telescopic Sleeve Antiswing Device for Shipboard Cranes

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jianli Wang ◽  
Shenghai Wang ◽  
Haiquan Chen ◽  
Anqi Niu ◽  
Guoliang Jin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Structural Design ◽  
Three Dimensional ◽  
Modeling And Analysis ◽  
Research Results ◽  
Simulation Results ◽  
Reduction Characteristics

In order to explore the dynamic characteristics of the telescopic sleeve antiswing device for shipboard cranes under coupling excitation, a three-dimensional dynamic model of the ship crane telescopic sleeve antiswing device is established in this study, and the accuracy of the model is verified through experiments. By dynamic analysis, the influence of sleeve extension and contraction, damper parameters, and ship excitation on the payload swing is found; meanwhile, the influence of payload swing on ship stability is discovered. At the same time, the simulation results show that the three-dimensional dynamic model can accurately simulate the swing reduction characteristics of the antiswing device. The in-plane and out-plane angles of the swing are reduced by 70% and 90%. The research results have great significance to further explore the antiswing mechanism and structural design of the mechanical antiswing device.

Utilizing an Adaptive Controller (Azadi Controller) for Trajectory Planning of PUMA 560 Robot

2011 ◽  
Vol 403-408 ◽  
pp. 4880-4887
Author(s):  
Sassan Azadi
Keyword(s):  
Steady State ◽  
Trajectory Planning ◽  
Positive Feedback ◽  
Fuzzy Controller ◽  
Research Work ◽  
Adaptive Controller ◽  
The Novel ◽  
Transient Responses ◽  
Simulation Results ◽  
Good Substitute

This research work was devoted to present a novel adaptive controller which uses two negative stable feedbacks with a positive unstable positive feedback. The positive feedback causes the plant to do the break, therefore reaching the desired trajectory with tiny overshoots. However, the two other negative feedback gains controls the plant in two other sides of positive feedback, making the system to be stable, and controlling the steady-state, and transient responses. This controller was performed for PUMA-560 trajectory planning, and a comparison was made with a fuzzy controller. The fuzzy controller parameters were obtained according to the PSO technique. The simulation results shows that the novel adaptive controller, having just three parameters, can perform well, and can be a good substitute for many other controllers for complex systems such as robotic path planning.

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