Design and Analysis of a Robotic Modular Leg Mechanism

2016 ◽  
Author(s):  
Wael Saab ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Body Height ◽  
Point Contact ◽  
Dynamic Simulations ◽  
Uneven Terrain ◽  
Quadruped Robots ◽  
System A ◽  
Passive Suspension System ◽  
And Performance ◽  
Multi Body ◽  
Body Dynamic

This paper presents the design and analysis of a reduced degree-of-freedom Robotic Modular Leg (RML) mechanism used to construct a quadruped robot. This mechanism enables the robot to perform forward and steering locomotion with fewer actuators than conventional quadruped robots. The RML is composed of a double four-bar mechanism that maintains foot orientation parallel to the base and decouples actuation for simplified control, reduced weight and lower cost of the overall robotic system. A passive suspension system in the foot enables a stable four-point contact support polygon on uneven terrain. Foot trajectories are generated and synchronized using a trot and modified creeping gait to maintain a constant robot body height, horizontal body orientation, and provide the ability to move forward and steer. The locomotion principle and performance of the mechanism are analyzed using multi-body dynamic simulations of a virtual quadruped and experimental results of an integrated RML prototype.

scholarly journals Modeling, Design, and Implementation of an Underactuated Gripper with Capability of Grasping Thin Objects

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 347
Author(s):  
Long Kang ◽  
Sang-Hwa Kim ◽  
Byung-Ju Yi
Keyword(s):  
Lower Cost ◽  
Point Contact ◽  
Torsion Spring ◽  
Passive Joint ◽  
Design And Implementation ◽  
Different Types ◽  
Dynamic Simulator ◽  
Multi Body ◽  
Body Dynamic ◽  
Underactuated Finger

Underactuated robotic grippers have the advantage of lower cost, simpler control, and higher safety over the fully actuated grippers. In this study, an underactuated robotic finger is presented. The design issues that should be considered for stable grasping are discussed in detail. This robotic finger is applied to design a two-fingered underactuated gripper. Firstly, a new three-DOF linkage-driven robotic finger that combines a five-bar mechanism and a double parallelogram is presented. This special architecture allows us to put all of the required actuators into the palm. By adding a torsion spring and a mechanical stopper at a passive joint, this underactuated finger mechanism can be used to perform parallel grasping, shape-adaptive grasping, and environmental contact-based grasp. Secondly, the dynamic model of this robotic finger is developed to investigate how to select an appropriate torsion spring. The dynamic simulation is performed with a multi-body dynamic simulator to verify our proposed approach. Moreover, static grasp models of both two-point and three-point contact grasps are investigated. Finally, different types of grasping modes are verified experimentally with a two-fingered underactuated robotic gripper.

An intelligent multiple-articulated rubber-tired vehicle based on automatic steering and trajectory following method

2021 ◽  
pp. 107754632199918
Author(s):  
Lei Xiao ◽  
Ke Wang ◽  
Sheng Zhou ◽  
Sai Ma
Keyword(s):  
Computational Cost ◽  
Steering System ◽  
Visual Navigation ◽  
Dynamic Simulations ◽  
Automatic Steering ◽  
Trajectory Following ◽  
Design Speed ◽  
Prediction Control ◽  
Multi Body ◽  
Body Dynamic

For manually driven rubber trams to track, virtual tracks can easily cause driver fatigue. Therefore, based on visual navigation, an automatic steering and trajectory following method are proposed. First, the vehicle kinematic and dynamic model of the Delight Tram is proposed. Then, the automatic steering and trajectory following methods are introduced, which are based on model prediction control and Ackermann steering theory, respectively. Finally, the effectiveness of the proposed methods has been evaluated via both multi-body dynamic simulations and road tests under various working conditions. The results show that the vehicle has excellent steering and trajectory following ability whether in a transient phase or a steady-state circumference. Furthermore, the steering system can stabilize the vehicle in the whole range of design speed, with a smaller computational cost.

Stochastic Responses of Vehicle-Bridge Coupling System

2012 ◽  
Vol 178-181 ◽  
pp. 2312-2315
Author(s):  
Min Lin ◽  
Xiang Wei Zhang ◽  
Si Yuan Chen
Keyword(s):  
Active Suspension ◽  
Coupling Model ◽  
System A ◽  
Coupling System ◽  
Virtual Vehicle ◽  
Stochastic Controller ◽  
Multi Body ◽  
Pseudo Excitation ◽  
Method Model ◽  
Body Dynamic

In this paper,we want to obtain the research of virtual vehicle-birdge coupling system, a vehicle-bridge coupling model was established based on the multi-point Pseudo Excitation Method model, and then the simulation result was gained by ANSYS. First,a detailed multi-body dynamic model of the vehicle was established by using ADAMS/VIEW software package; secondly, a stochastic controller was designed for active suspension system and worked out by means of Matlab/Simulink, the proposed control algorithm was integrated with the multi-body dynamic vehicle model and the coupling system simulations could be performed repeatedly until a satisfactory controller was achieved, the system was compared with a conventional passive one. Simulation results showed that the proposed active suspension considerably improved both the ride and handling performance of the vehicle.

scholarly journals Design and Analysis of a Multi-Legged Robot with Pitch Adjustive Units

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Qiang Ruan ◽  
Jianxu Wu ◽  
Yan-an Yao
Keyword(s):  
Complex Terrain ◽  
Degrees Of Freedom ◽  
Virtual Model ◽  
Legged Robot ◽  
Dynamic Simulations ◽  
Compact Structure ◽  
Multi Body ◽  
6 Degrees Of Freedom ◽  
Body Dynamic ◽  
Pitch Adjustment

AbstractThe paper proposes a novel multi-legged robot with pitch adjustive units aiming at obstacle surmounting. With only 6 degrees of freedom, the robot with 16 mechanical legs walks steadily and surmounts the obstacles on the complex terrain. The leg unit with adjustive pitch provides a large workspace and empowers the legs to climb up obstacles in large sizes, which enhances the obstacle surmounting capability. The pitch adjustment in leg unit requires as few independent adjusting actuators as possible. Based on the kinematic analysis of the mechanical leg, the biped and quadruped leg units with adjustive pitch are analyzed and compared. The configuration of the robot is designed to obtain a compact structure and pragmatic performance. The uncertainty of the obstacle size and position in the surmounting process is taken into consideration and the parameters of the adjustments and the feasible strategies for obstacle surmounting are presented. Then the 3D virtual model and the robot prototype are built and the multi-body dynamic simulations and prototype experiments are carried out. The results from the simulations and the experiments show that the robot possesses good obstacle surmounting capabilities.

Application Fuzzy Logic System for Accurate Sheet Trim Shower Position

2019 ◽  
Vol 3 (1) ◽  
pp. 186-192
Author(s):  
Yudi Wibawa
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Dc Motor ◽  
Automation System ◽  
Paper Making ◽  
System A ◽  
Accurate Position ◽  
And Performance ◽  
Better Than ◽  
Logic System

This paper aims to study for accurate sheet trim shower position for paper making process. An accurate position is required in an automation system. A mathematical model of DC motor is used to obtain a transfer function between shaft position and applied voltage. PID controller with Ziegler-Nichols and Hang-tuning rule and Fuzzy logic controller for controlling position accuracy are required. The result reference explains it that the FLC is better than other methods and performance characteristics also improve the control of DC motor.

Continuous multi-body dynamic analysis of float-over deck installation with rapid load transfer technique in open waters

2021 ◽  
Vol 224 ◽  
pp. 108729
Author(s):  
Shujie Zhao ◽  
Xun Meng ◽  
Huajun Li ◽  
Dejiang Li ◽  
Qiang Fu
Keyword(s):  
Dynamic Analysis ◽  
Load Transfer ◽  
Multi Body ◽  
Body Dynamic

scholarly journals Research on Coupled Dynamic Model of Tracked Vehicles and Its Solving Method

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Yuliang Li ◽  
Chong Tang
Keyword(s):  
Dynamic Performance ◽  
Tractive Force ◽  
Actual Structure ◽  
Discrete Method ◽  
Tracked Vehicles ◽  
Coupled Equations ◽  
Calculation Results ◽  
Dynamic Software ◽  
Multi Body ◽  
Body Dynamic

In order to conveniently analyze the dynamic performance of tracked vehicles, mathematic models are established based on the actual structure of vehicles and terrain mechanics when they are moving on the soft random terrain. A discrete method is adopted to solve the coupled equations to calculate the acceleration of the vehicle’s mass center and tractive force of driving sprocket. Computation results output by the model presented in this paper are compared with results given by the model, which has the same parameters, built in the multi-body dynamic software. It shows that the steady state calculation results are basically consistent, while the model presented in this paper is more convenient to be used in the optimization of structure parameters of tracked vehicles.

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