Dynamics and Control of Four Wheeled Differentially Steered UGVs

2014 ◽  
Author(s):  
Andrew Narvesen ◽  
Majura F. Selekwa
Keyword(s):  
Autonomous Navigation ◽  
Research Area ◽  
Control Parameters ◽  
Ground Vehicles ◽  
Friction Forces ◽  
Straight Line ◽  
Dynamics And Control ◽  
Left And Right ◽  
And Control ◽  
Very High

Autonomous navigation of ground vehicles is a growing research area. Skid steered wheeled ground vehicles are of interest because of the system’s relatively easy control parameters. Steered wheels require actuation and control for the steering and speed of the steered wheels while skid steering just requires actuation and control of the wheel speeds, usually just a left and right wheel speed. Four Wheeled differentially steered vehicles are built primarily for straight line motion since the instantaneous centers of zero velocities for the four wheels are always at infinity when there is no sliding in the wheels. When the vehicle has to negotiate a corner, it uses the differential velocities between sides to force the wheels to slide and perform the cornering maneuver. Maneuvering is difficult when the ground friction is very high because of undue stresses in the axle structure. This paper analyses the dynamics of such vehicles that relates the traction and skid friction forces and proposes a suitable control system. At this time, the paper is supported by simulation results while experimental work is still going on.

Experimental Investigation on the Dynamic Behavior of Chaotic Jumping in Inverted Flexible Pendulum Under Harmonic Excitation

2018 ◽  
Author(s):  
Hartiny A. Kahar ◽  
Elmira Madadi ◽  
Dirk Söffker
Keyword(s):  
Multiple Equilibria ◽  
Dynamical Behavior ◽  
Harmonic Excitation ◽  
Control Parameters ◽  
Pendulum System ◽  
Dynamics And Control ◽  
Design Requirements ◽  
And Control ◽  
Two Equilibria ◽  
Stimulation Of

Control of flexible systems is effected by design requirements and also manufacturing aspects. The dynamics and control of such systems are challenging, especially in the case of an inverted flexible pendulum system. The experimental study of the dynamical behavior of this kind of system showing jumping phenomenon between three equilibria is not considered in detail in literatures so far. The paper focuses on studying the effects of some parameters to the dynamics of the flexible pendulum. By varying the excitation parameters, control parameters, as well as other distinguished mechanical parameters, different phenomena are observed in experiments discussed in this contribution. In this study, a custom built inverted flexible pendulum on cart system under PID-controlled harmonic excitation is considered. Data are collected from both cart excitation signal and displacement of the pendulum, also to observe their correlation towards jumping behavior. Effects of the variation of the parameters leading to changes in chaotic jumping patterns. Multiple equilibria are observed and analyzed. It can be concluded that depending on the excitation amplitudes, frequencies, and controller parameters, the minimum of two equilibria with an unstable third equilibrium can be detected while jumping phenomena between the equilibria are observed. Questions about the stimulation of the jumping by impulses resulting from imperfect sinusoidal excitation due to control limitations are discussed.

scholarly journals Non Linear Modelling and Control of Hydraulic Actuators

10.14311/354 ◽  
2002 ◽  
Vol 42 (3) ◽  
Author(s):  
B. Šulc ◽  
J. A. Jan
Keyword(s):  
Linear Models ◽  
Hydraulic Actuator ◽  
Friction Forces ◽  
Linear Modelling ◽  
Non Linear ◽  
Object Oriented Approach ◽  
Physical Laws ◽  
And Control ◽  
Nonlinear State ◽  
Very High

This paper deals with non-linear modelling and control of a differential hydraulic actuator. The nonlinear state space equations are derived from basic physical laws. They are more powerful than the transfer function in the case of linear models, and they allow the application of an object oriented approach in simulation programs. The effects of all friction forces (static, Coulomb and viscous) have been modelled, and many phenomena that are usually neglected are taken into account, e.g., the static term of friction, the leakage between the two chambers and external space. Proportional Differential (PD) and Fuzzy Logic Controllers (FLC) have been applied in order to make a comparison by means of simulation. Simulation is performed using Matlab/Simulink, and some of the results are compared graphically. FLC is tuned in a such way that it produces a constant control signal close to its maximum (or minimum), where possible. In the case of PD control the occurrence of peaks cannot be avoided. These peaks produce a very high velocity that oversteps the allowed values.

Dynamics and Control of a Flexible Flapping Wing Aircraft

2012 ◽  
Vol 246-247 ◽  
pp. 537-542
Author(s):  
Zhuang Zhao ◽  
Hai Yuan Jiang ◽  
Hua Chang ◽  
Jing Guo
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Research Area ◽  
Aerodynamic Performance ◽  
Flapping Wing ◽  
Aerodynamic Forces ◽  
Dynamics And Control ◽  
Wind Velocities ◽  
Set Up ◽  
And Control

To investigate the aerodynamic performance of a flexible flapping wing aircraft, a flapping-wing system were design and an experiment were set up to measure the unsteady aerodynamic forces of the flapping motion. The thrust formula and resistance formula described aerodynamic forces. The lift and thrust of this mechanism were measured for different angles of attack and wind velocities. Results indicate that the thrust increases with the flapping frequency and the lift increase with the wind velocity, while the lift coefficient decreases while the velocity increases. It is realized that the wing’s transformation which imitated birds leads less resistance when flapping upward which impacts the aerodynamic lift generation and the bionic winglet leads to a change in the leading edge vortex and span-wise flow structures, which decrease the airflow’s backward pull. Models were introduced which were used in the design process and show its aerodynamic performance. The flexible flapping wing vehicle is still an open research area.

Dynamics and Control of a Small-Scale Boom Crane

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
Ehsan Maleki ◽  
William Singhose
Keyword(s):  
Material Handling ◽  
Physical Structure ◽  
Control Technique ◽  
Small Scale ◽  
Command Shaping ◽  
Straight Line ◽  
Theoretical Predictions ◽  
Dynamics And Control ◽  
And Control ◽  
Boom Crane

Cranes are vital to many manufacturing and material-handling processes. However, their physical structure leads to flexible dynamic effects that limit their usefulness. Large payload swings induced by either intentional crane motions or external disturbances decrease positioning accuracy and can create hazardous situations. Boom cranes are one of the most dynamically complicated types of cranes. Boom cranes cannot transfer the payload in a straight line by actuating only one axis of motion because they have rotational joints. This paper presents a nonlinear model of a boom crane. A large range of possible motions is analyzed to investigate the dynamic behavior of the crane when it responds to operator commands. A command-shaping control technique is implemented, and its effectiveness on this nonlinear machine is analyzed. Experimental results verify key theoretical predictions.

Probability model for control parameters in the aircraft's information and control systems

2018 ◽  
Vol 2 ◽  
pp. 9-16
Author(s):  
A. Al-Ammouri ◽  
◽  
H.A. Al-Ammori ◽  
A.E. Klochan ◽  
A.M. Al-Akhmad ◽  
...  
Keyword(s):  
Control Systems ◽  
Probability Model ◽  
Control Parameters ◽  
And Control

PROJECT ON ELECTRONIC STEERING SYSYTEM

2018 ◽  
Vol 4 (5) ◽  
pp. 7
Author(s):  
Shivam Dwivedi ◽  
Prof. Vikas Gupta
Keyword(s):  
Steering System ◽  
Essential Elements ◽  
Variable Pressure ◽  
Passenger Cars ◽  
Control Techniques ◽  
Steering Mechanism ◽  
Dynamics And Control ◽  
Active Research ◽  
Electronic Steering ◽  
And Control

As the four-wheel steering (4WS) system has great potentials, many researchers' attention was attracted to this technique and active research was made. As a result, passenger cars equipped with 4WS systems were put on the market a few years ago. This report tries to identify the essential elements of the 4WS technology in terms of vehicle dynamics and control techniques. Based on the findings of this investigation, the report gives a mechanism of electronically controlling the steering system depending on the variable pressure applied on it. This enhances the controlling and smoothens the operation of steering mechanism.

Sign in / Sign up

Export Citation Format

Share Document