Review of electro-hydraulic hitch system control method of automated tractors

The automatic and intelligent degree of tractor hitch system determines the operations quality,efficiency,tractor power output and energy consumption,and automatic control of electro-hydraulic hitch is one of the key technical problems in the realization of automated tractor.In this study,the adjustment methods and characteristics of electro-hydraulic hitch system were summarized.The development of electro-hydraulic hitch control technologies was elaborated and analyzed from both the electro-hydraulic control strategy and slip control strategy perspectives.The implementation methods and control characteristics were discussed.A new idea for the development of automated tractor was put forward that integrating cutting-edge technologies such as big data,fusion control and artificial intelligence.In addition,based on the precise and efficient control of electro-hydraulic hitch system,a high reliability of the control system of the tractor with intelligent application of the control algorithm was obtained.The results can provide a reference for the precise operation of automated tractors under the big data in agriculture.

Longitudinal and lateral slip control of autonomous wheeled mobile robot for trajectory tracking

This research formulates a path-following control problem subjected to wheel slippage and skid and solves it using a logic-based control scheme for a wheeled mobile robot （WMR）. The novelty of the proposed scheme lies in its methodology that considers both longitudinal and lateral slip components. Based on the derived slip model, the controller for longitudinal motion slip has been synthesized. Various control parameters have been studied to investigate their effects on the performance of the controller resulting in selection of their optimum values. The designed controller for lateral slip or skid is based on the proposed side friction model and skid check condition. Considering a car-like WMR, simulation results demonstrate the effectiveness of the proposed control scheme. The robot successfully followed the desired circular trajectory in the presence of wheel slippage and skid. This research finds its potential in various applications involving WMR navigation and control.

Determination of the dynamic characteristics of locomotive drive systems under re-adhesion conditions using wheel slip controller

To investigate the re-adhesion and dynamic characteristics of the locomotive drive system with wheel slip controller,a co-simulation model of the train system was established by SIMPACK and MATLAB/SIMULINK.The uniform running and starting conditions were considered,and the influence of structural stiffness of the drive system and the wheel slip controller on the re-adhesion and acceleration performance of the locomotive was investigated.The simulation results demonstrated that the stick-slip vibration is more likely to occur in locomotives with smaller structural stiffnesses during adhesion reduction and recovery processes.There are many frequency components in the vibration acceleration spectrum of the drive system,because the longitudinal and rotational vibrations of the wheelset are coupled by the wheel‒rail tangential force when stick-slip vibration occurs.In general,increasing the structural stiffness of the drive system and reducing the input energy in time are effective measures to suppress stick-slip vibration.It should also be noted that inappropriate matching of the wheel slip controller and drive system parameters may lead to electro-mechanical coupling vibration of the drive system,resulting in traction force fluctuation and poor acceleration performance.