Longitudinal Control of an Autonomous Truck With Unobserved Gears

2021 ◽  
Author(s):  
Jose Nuno A. D. Bueno ◽  
Lucas B. Marcos ◽  
Kaio D. T. Rocha ◽  
Marco H. Terra
Keyword(s):  
Longitudinal Control

Predictors of Problematic Video Game Usage in Childhood and Adolescence

2013 ◽  
Vol 59 (3) ◽  
pp. 153-164 ◽  
Author(s):  
Thomas Mößle ◽  
Florian Rehbein
Keyword(s):  
Social Environment ◽  
School Children ◽  
Video Game ◽  
Video Gaming ◽  
Control Group ◽  
Childhood And Adolescence ◽  
Longitudinal Control ◽  
Peer Problems ◽  
Media Usage ◽  
Usage Patterns

Aim: The aim of this article is to work out the differential significance of risk factors of media usage, personality and social environment in order to explain problematic video game usage in childhood and adolescence. Method: Data are drawn from the Berlin Longitudinal Study Media, a four-year longitudinal control group study with 1 207 school children. Data from 739 school children who participated at 5th and 6th grade were available for analysis. Result: To explain the development of problematic video game usage, all three areas, i. e. specific media usage patterns, certain aspects of personality and certain factors pertaining to social environment, must be taken into consideration. Video game genre, video gaming in reaction to failure in the real world (media usage), the children’s/adolescents’ academic self-concept (personality), peer problems and parental care (social environment) are of particular significance. Conclusion: The results of the study emphasize that in future – and above all also longitudinal – studies different factors regarding social environment must also be taken into account with the recorded variables of media usage and personality in order to be able to explain the construct of problematic video game usage. Furthermore, this will open up possibilities for prevention.

Field Theory for Some Traffic Phenomena and Fundamental Diagram

2021 ◽  
pp. 036119812110064
Author(s):  
Daiheng Ni
Keyword(s):  
Field Theory ◽  
Traffic Flow ◽  
Causal Effect ◽  
Microscopic Approach ◽  
Fundamental Diagram ◽  
Longitudinal Control ◽  
Effect Analysis ◽  
Vehicle Trajectories ◽  
Vehicle Motion ◽  
Cross Reference

A fundamental diagram consists of a scatter of traffic flow data sampled at a specific location and aggregated from vehicle trajectories. These trajectories, if presented equivalently, constitute a microscopic version of the (conventional) fundamental diagram. The cross-reference between vehicle trajectories and the microscopic fundamental diagram provides details of vehicle motion dynamics which allow causal-effect analysis on some traffic phenomena and further reveal the microscopic basis of the conventional fundamental diagram. This observation inspires theoretical modeling by a microscopic approach to address traffic phenomena and the conventional fundamental diagram. Derived from the field theory of traffic flow, the longitudinal control model is capable of serving the purpose without the modifications or exceptions used by other approaches.

scholarly journals An Optimal Longitudinal Control Strategy of Platoons Using Improved Particle Swarm Optimization

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhizhou Wu ◽  
Zhibo Gao ◽  
Wei Hao ◽  
Jiaqi Ma
Keyword(s):  
Particle Swarm Optimization ◽  
Control Strategy ◽  
Ride Comfort ◽  
Particle Swarm ◽  
Experimental Simulation ◽  
Driving Safety ◽  
Relative Speed ◽  
Longitudinal Control ◽  
Swarm Optimization ◽  
Improved Particle Swarm Optimization

Most existing longitudinal control strategies for connected and automated vehicles (CAVs) have unclear adaptability without scientific analysis regarding the key parameters of the control algorithm. This paper presents an optimal longitudinal control strategy for a homogeneous CAV platoon. First of all, the CAV platoon models with constant time-headway gap strategy and constant spacing gap strategy were, respectively, established based on the third-order linear vehicle dynamics model. Then, a linear-quadratic optimal controller was designed considering the perspectives of driving safety, efficiency, and ride comfort with three performance indicators including vehicle gap error, relative speed, and desired acceleration. An improved particle swarm optimization algorithm was used to optimize the weighting coefficients for the controller state and control variables. Based on the Matlab/Simulink experimental simulation, the analysis results show that the proposed strategy can significantly reduce the gap error and relative speed and improve the flexibility and initiative of the platoon control strategy compared with the unoptimized strategies. Sensitivity analysis was provided for communication lag and actuator lag in order to prove the applicability and effectiveness of this proposed strategy, which will achieve better distribution of system performance.

Effect of Variations in Weight or Normal Acceleration on the Ceiling of Jet-Propelled Aircraft

1955 ◽  
Vol 59 (534) ◽  
pp. 435-437
Author(s):  
P. L. Sutcliffe
Keyword(s):  
High Altitude ◽  
Normal Force ◽  
Control Surface ◽  
Military Aircraft ◽  
Longitudinal Control ◽  
The Past ◽  
Normal Acceleration

The ability to manoeuvre at high altitude has become one of the main requirements in the design of modern military aircraft. Ability to manoeuvre enables the fighter pilot to execute tight turns during the attack on a bomber and the bomber pilot to perform evasive manoeuvres and so make the task of the fighter more difficult.Normally the main manoeuvre considered is the application of increased normal acceleration, or g, and if we assume that (a) there is sufficient pitching power available from the longitudinal control surface to increase the wing incidence to give the necessary increase in normal force, and (b) that the new wing incidence is below the stalling incidence of the wing, then the degree of manoeuvrability available is a function of thrust and drag alone. In the past the manoeuvrability required at a given altitude has been expressed in terms of the rate of climb available at that altitude and thus we have such definitions as “ the 1,000 ft./min. ceiling ” and so on.

scholarly journals Adaptive Longitudinal Control of UAVs with Direct Lift Control

2016 ◽  
Vol 49 (1) ◽  
pp. 296-301 ◽  
Author(s):  
Ravi Jaiswal ◽  
Abhishek Shastry ◽  
Swati Swarnkar ◽  
Mangal Kothari
Keyword(s):  
Longitudinal Control ◽  
Lift Control

Design and Experimental Implementation of Longitudinal Control for a Platoon of Automated Vehicles

1998 ◽  
Vol 122 (3) ◽  
pp. 470-476 ◽  
Author(s):  
R. Rajamani ◽  
S. B. Choi ◽  
B. K. Law ◽  
J. K. Hedrick ◽  
R. Prohaska ◽  
...  
Keyword(s):  
Control System ◽  
Torque Converter ◽  
Stable Operation ◽  
Automated Vehicles ◽  
Longitudinal Control ◽  
The Public ◽  
Automated Highways ◽  
Experimental Implementation ◽  
Special Challenge ◽  
Upper Level

This paper presents the design and experimental implementation of a longitudinal control system for the operation of automated vehicles in platoons. The control system on each vehicle is designed to have a hierarchical structure and consists of an upper level controller and a lower level controller. The upper controller determines the desired acceleration for each vehicle in the platoon so as to maintain safe string-stable operation even at very small intervehicle spacing. The lower controller utilizes vehicle-specific parameters and determines the throttle and/or brake commands required to track the desired acceleration. A special challenge handled in the design of the lower level controller is low-speed operation that involves gear changes and torque converter dynamics. The paper also presents the design of longitudinal intra-platoon maneuvers that are required in order to allow any car in the platoon to make an exit. The paper presents extensive experimental results from the public NAHSC demonstration of automated highways conducted in August 1997 at San Diego, California. The demonstration included an eight-car platoon operating continuously over several weeks with passenger rides given to over a thousand visitors. The maneuvers demonstrated included starting the automated vehicles from complete rest, accelerating to cruising speed, allowing any vehicle to exit from the platoon, allowing new vehicles to join the platoon and bringing the platoon to a complete stop at the end of the highway. [S0022-0434(00)01903-1]

Sign in / Sign up

Export Citation Format

Share Document