scholarly journals Strategies of traversing obstacles and the simulation for a forestry chassis

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877390 ◽  
Author(s):  
Yue Zhu ◽  
Jiangming Kan ◽  
Wenbin Li ◽  
Feng Kang
Keyword(s):  
Multibody Dynamics ◽  
Inclination Angle ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Hydraulic Cylinder ◽  
Single Side ◽  
Simulation Results ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Small Inclination

As to the complicated terrain in forest, forestry chassis with an articulated body with three degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is a novel chassis that can surmount obstacles. In addition, the rear frame of FC-3DOF&LW is regarded as the platform to carry equipment. Small inclination angle for rear frame contributes to stability and ride comfort. This article describes the strategy of traversing obstacles and simulation for FC-3DOF&LW that drives in forest terrain. First, key structures of FC-3DOF&LW are briefly introduced, which include articulated structure with three degrees of freedom and luffing wheel-leg. Based on the sketch of luffing wheel-leg, the movement range of luffing wheel-leg is obtained by hydraulic cylinder operation. Second, the strategy of crossing obstacles that are simplified three models of terrain is presented, and the simulation for surmounting obstacles is constructed in multibody dynamics software. The simulation results demonstrate that the inclination angle of rear frame is 18° when slope is 30°. A maximum 12° decrease of inclination angle for rear frame can be acquired when luffing wheel-legs are applied. For traversing obstacles with both sides, the maximum inclination angle of rear frame is about 1.2° and is only 3° for traversing obstacles with single side.

Actuator Array Dynamics Incorporating Actuator Inertia

2013 ◽  
Author(s):  
Mark D. Bedillion
Keyword(s):  
Degrees Of Freedom ◽  
Friction Model ◽  
Object Motion ◽  
Prior Work ◽  
Control Laws ◽  
Distributed Manipulation ◽  
Actuator Arrays ◽  
Simulation Results ◽  
Two Degree Of Freedom ◽  
Three Degrees Of Freedom

Actuator arrays are planar distributed manipulation systems that use multiple two degree-of-freedom actuators to manipulate objects with three degrees of freedom (x, y, and θ). Prior work has discussed actuator array dynamics while neglecting the inertia of the actuators; this paper extends prior work to the case of non-negligible actuator inertia. The dynamics are presented using a standard friction model incorporating stiction. Simulation results are presented that show object motion under previously derived control laws.

Operational Space Prescribed Tracking Performance and Compliance in Flexible Joint Robots

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Abdelrahem Atawnih ◽  
Zoe Doulgeri ◽  
George A. Rovithakis
Keyword(s):  
Degrees Of Freedom ◽  
Position Tracking ◽  
Admittance Control ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Operational Space ◽  
Control Scheme ◽  
Simulation Results ◽  
Flexible Joint Manipulator ◽  
Three Degrees Of Freedom

In this work, an admittance control scheme is proposed utilizing a highly robust prescribed performance position tracking controller for flexible joint robots which is designed at the operational space. The proposed control scheme achieves the desired impedance to the external contact force as well as superior position tracking in free motion without any robot model knowledge, as opposed to the torque based impedance controllers. Comparative simulation results on a three degrees-of-freedom (3DOF) flexible joint manipulator, illustrate the efficiency of the approach.

The Kinematics Model and Simulation of a Subminiature Based on Marine Ranching

2014 ◽  
Vol 909 ◽  
pp. 135-140
Author(s):  
Jie Jiang Shao ◽  
Feng Peng Wei ◽  
Lan Zhen
Keyword(s):  
Degrees Of Freedom ◽  
Complex Environment ◽  
Kinematics Model ◽  
Model And Simulation ◽  
Simulation Results ◽  
Freedom Movement ◽  
Three Degrees Of Freedom

A subminiature submersible has been designed on the basis of the condition of the marine ranching, especially the shape of the submersible in view of the complex environment of marine ranching. Its mainly designed from three major movements, namely advance, ups-downs and yawing movement; it can complete three degrees of freedom movement. At the same time a force analysishas beengiven. Thetransfer functions have been deduced, and the simulation structure has been designed according to its kinematics model. According to the simulation results, the feasibility of the kinematics model was verified.

Modeling and Simulation of Motorcycle Ride Comfort Based on Bump Road

2010 ◽  
Vol 139-141 ◽  
pp. 2643-2647 ◽  
Author(s):  
Dong Mei Yuan ◽  
Xiao Mei Zheng ◽  
Ying Yang
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Lagrange Equation ◽  
Equations Of Motion ◽  
Vertical Displacement ◽  
Dynamics Model ◽  
Body Dynamics ◽  
Space Formulation ◽  
Simulation Results ◽  
Multi Body

Through analyzing the motion when motorcycle runs on the bump road, the 5-DOF multi-body dynamics model of motorcycle is developed, the degrees of freedom include vertical displacement of sprung mass, rotation of sprung mass, vertical displacement of driver, and vertical displacement of front and rear suspension under sprung mass. According to Lagrange Equation, the differential equations of motion and state-space formulation are derived. Then bump road is simulated by triangle bump, and input displacement is programmed by MATLAB. With the input of bump road, motorcycle ride comfort is simulated, and the simulation results are verified by experiment results combined with two channels tire-coupling road simulator. It indicates that the simulation results and experiment results match well; the 5-DOF model has guidance for development of motorcycle ride comfort.

Performance Analysis of 3-URU Spherical Parallel Mechanism Designed Based on Velocity Transmission and Force Constraint Indices

2015 ◽  
Vol 758 ◽  
pp. 71-76
Author(s):  
Syamsul Huda ◽  
Syafri ◽  
Mulyadi Bur
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Output Link ◽  
Kinematic Synthesis ◽  
Platform Motion ◽  
Spherical Parallel Mechanism ◽  
Velocity Transmission ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Spherical Motion

In this paper was observed performances of developed three degrees of freedom (dof) parallel mechanism named 3-URU spherical parallel mechanism. The mechanism is composed of three identical limbs mounted symmetrically to base (fixed link) and platform (output link). The limb is constructed by universal-revolute and universal joints. The kinematic constants of mechanism consisting of link lengths, radius of platform, radius of base, mounting angle of limb and platform to base and platform were determined with consideration of velocity transmission and force constraint indices. To evaluate performance of mechanism, it was manufactured a prototype of mechanism designed base on these two mentioned indices. There are three steps proposed to realize the mechanism, (i) kinematic synthesis to determine of kinematic constants, (ii) design of mechanical components to define shape and dimension of links and joints by considering collision in wokingspace and static analysis, (iii) evaluation of mechanism performances consisting of workingspace, controllability of platform motion and static payload. Based on obtained results, it can be clarified that, the mechanism can produce spherical motion of platform which rotates on steady point recognized as center of platform rotation. The platform can achieve maximum inclination angle, 80 degree and at this posture occurs translational error, 0.0102 mm. On the other hand, the mechanism can support payload ten times of weight of moving parts.

scholarly journals A novel forestry chassis with an articulated body with 3 degreesof freedom and installed luffingwheel-legs

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774710 ◽  
Author(s):  
Yue Zhu ◽  
Jiangming Kan ◽  
Wenbin Li ◽  
Feng Kang
Keyword(s):  
Complex Terrain ◽  
Mechanical Model ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Hydraulic Cylinder ◽  
The Other ◽  
Dynamics Simulation ◽  
Forest Industry ◽  
Body Dynamics ◽  
Multi Body

One of the challenging problems in the forest industry is to develop a chassis that is well-adapted to the complex terrain conditions in the forest. In this article, a novel forestry chassis with an articulated body with 3 degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is proposed, and the mechanical model of the luffing wheel-leg is built. Based on the mechanical model, the hydraulic cylinder velocity that involves the wheel-leg luffing is calculated. The process of surmounting the obstacle is presented by multi-body dynamics simulation. To demonstrate the improvement of ride comfort, the other simulation of the chassis with an articulated body with 3 degrees of freedom (FC-3DOF) is contrasted in multi-dynamics software. The final result shows that curves of barycenter displacement for FC-3DOF&LW with the front and rear frames are well matched when the front frame surmounts the obstacle; in particular, the barycenter displacement is almost stable when the rear frame surmounts the obstacle. The maximum rotated angle of the articulated joint reaches almost 37° without the luffing wheel-leg, whereas it is only 4° with FC-3DOF&LW, a decrease of 89.1%. Moreover, the acceleration trend for FC-3DOF&LW is more stable than that for FC-3DOF.

Research on Hydraulic and Control System of Manipulator

2012 ◽  
Vol 482-484 ◽  
pp. 1350-1353
Author(s):  
Ji Li He
Keyword(s):  
Degrees Of Freedom ◽  
Hydraulic Cylinder ◽  
Simulation Software ◽  
Simulation Function ◽  
Hydraulic Circuit ◽  
Hydraulic Simulation ◽  
Industrial Manipulator ◽  
Cylindrical Coordinate ◽  
And Control ◽  
Three Degrees Of Freedom

The industrial manipulator has been introduced. The manipulator of cylindrical coordinate type provides with three degrees of freedom including rotation, lifting and expansion, which has corresponding rotation structure, lifting structure, expansion structure. All parts are drove and controlled by using hydraulic cylinder. FluidSIM-H is hydraulic simulation software and tightly integrated the CAD function and simulation function. To simulate and analyze the operation of hydraulic circuit which based on the physical model of hydraulic element and LOGO control. The results showed that the industrial manipulator can work reliably.

Multi-Degree-of-Freedom Modeling of Mechanical Snubbing Systems

2011 ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Experimental Data ◽  
Data Collection ◽  
Rigid Body ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Rigid Frame ◽  
Identification Technique ◽  
Simulation Results ◽  
Stiffness And Damping ◽  
Three Degrees Of Freedom

This paper presents a multi-degree-of-freedom model for the analysis of mechanical snubbing in elastomeric isolators. The model uses a system of elastomeric isolators and snubbers to assemble a rigid body with three degrees-of-freedom to a rigid frame. The isolators are supplemented by the snubbing system so as to limit the displacement of the rigid body in all three directions of motion when the system undergoes transient loading or overloading conditions. The model is piecewise non-linear and uses normalized Bouc-Wen elements in order to capture inherent hysteresis of the elastomeric isolators and the snubbing system as well as the transition in stiffness and damping properties resulting due to inherent coupling between the isolators and the snubbing system. Separate elements are used to model the enhanced stiffness resulting from the snubbing system in the translational directions of motion. A set of elastomeric isolators and snubbing systems is used for data collection, characterization and model validation. The data collection is carried out at multiple strain amplitudes and strain rates. A conventional least squares based parameter identification technique is used for characterization. The completely characterized model is then used for simulating the response of the rigid body and the simulation results are compared to experimental data. The simulation results are found to be in general agreement with the experimental data.

scholarly journals An Investigation on a Novel 3-RCU Flexible Micromanipulator

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 423 ◽  
Author(s):  
Junnan Qian ◽  
Yangmin Li ◽  
Lukai Zhuge
Keyword(s):  
Carrying Capacity ◽  
Degrees Of Freedom ◽  
Transmission Efficiency ◽  
Element Analysis ◽  
Margin Of Error ◽  
Simulation Results ◽  
Amplification Mechanism ◽  
Working Performance ◽  
Three Degrees Of Freedom ◽  
Ansys Workbench

A novel type of spatial three revolute-cylindrical-universal (3-RCU) flexible micro manipulator is designed based on flexible hinges, and analyzed by finite element analysis (FEA). The piezoelectric actuators are adopted as driving devices in this platform, a new lever amplification mechanism is designed as its micro-displacement amplification mechanism, the workspace of the platform is enlarged, and the theoretical and simulation amplification ratios of the amplification mechanism are 3.056 and 2.985, respectively. The margin of error is just 2.3%. In space, the 3-RCU platform can realize the micro movement of three degrees of freedom. Also, the platform has a high carrying capacity, less motion loss, and the transmission efficiency is higher when the platform works. The decoupling performance, stress under extreme conditions and natural frequency of the platform are simulated by ANSYS Workbench software. A series of simulation analyses show the feasibility and security of the platform. The platform has good decoupling and working performance. The simulation results show that the platform has high simulation stiffness and high positioning accuracy.

scholarly journals Hierarchical Control of Nonlinear Active Four-Wheel-Steering Vehicles

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2930 ◽  
Author(s):  
Jie Tian ◽  
Jie Ding ◽  
Yongpeng Tai ◽  
Ning Chen
Keyword(s):  
Degrees Of Freedom ◽  
Reference Model ◽  
Hierarchical Control ◽  
Front Wheel ◽  
Sideslip Angle ◽  
Yaw Rate ◽  
Rate Feedback ◽  
New Type ◽  
Simulation Results ◽  
Three Degrees Of Freedom

A new type of hierarchical control is proposed for a four-wheel-steering (4WS) vehicle, in which both the sideslip angle and yaw rate feedback are used, and the saturation of the control variables (i.e., the front and rear steering angles) is considered. The nonlinear three degrees of freedom (3DOF) 4WS vehicle model is employed to describe the uncertainties originating from the operating situations. Further, a normal front-wheel-steering (2WS) vehicle with a drop filter of the sideslip angle is selected as the reference model. The inputs for the rear and front steering angles of the linear 2DOF 4WS, required to achieve the performances described by the reference model, are obtained and controlled by the upper controller. Further, the lower controller is designed to eliminate the state error between the linear 2DOF and nonlinear 3DOF 4WS vehicle models. The simulation results of several vehicle models with/without the controller are presented, and the robustness of the hierarchical control system is analyzed. The simulation results indicate that using the proposed hierarchical controller yields the same performance between the nonlinear 4WS vehicle and the reference model, in addition to exhibiting good robustness.

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