The control of high-clearance electric vehicles based on pavement parameter estimations

Abstract

Agricultural high-clearance vehicles are different from traditional vehicles. Agricultural vehicles have particular features that are mainly suited for the agricultural vehicle's working environment. Farmland is relatively complex, mostly unknown and unstructured environment, and it is difficult to accurately model. The complex characteristics of farmland or hilly terrain demands that the agricultural machinery on the ground environment must have sufficient robustness. In this article, a soft road high vacant land vehicle model is established, and then, through the observation of force of tyres and the use of an existing tyre model recursive least square parameter estimation, the road adhesion coefficient is obtained. Considering that the sliding mode control can effectively solve the parameter uncertain nonlinear system, the model established herein has the advantages of robustness and fast response. The sliding mode control and the incremental proportional-integral control were used to test the uniform pavement and the separate pavement, respectively, and the results showed that the sliding mode control was closer to the target value than the incremental proportional-integral control but was less stable than the incremental proportional-integral control on the uniform road surface; in addition, the sliding mode control was superior to the incremental proportional-integral control on the separate road surface.

Development of Online Adaptive Traction Control for Electric Robotic Tractors

“…Due to the need of having high robustness to bounded parameter variations and the modeling imperfections that exist in wheel-terrain interaction systems, and also the issue of unmodeled dynamics due to pitch and roll moments, a sliding mode control (SMC) technique was proposed in this study. SMC has shown superior performance to other controllers such as PI in our previous study [3]. The controller was first designed without considering parameter variations, and later it was made robust to bounded parametric variations.…”

“…First, based on the procedure described in [3,43,51], the wheel torque balance in Equation ( 5) is estimated as J•…”

“…To leverage on the advantages of electric vehicle technologies, electric tractors were developed for pesticide applications and other agricultural purposes. The main advantages are that such operation does not require high power; as such, their power demand can be met by the electric batteries [3][4][5][6][7][8]. Though much progress has been achieved on improving batteries' performance, its energy density is still lower than that of conventional fuel, and the cost is still high [9][10][11][12][13].…”

Review and Comparison of Clearance Control Strategies

“…The existence of kinematic pair clearance will also lead to a collision between the mechanisms, resulting in elastic vibration, excess force, noise, and wear [9], which may eventually lead to oil contamination and loss of control or damage to the system. According to statistical analysis, approximately 30-80% of equipment damage is due to wear between mechanical components [10], and wear is also one of the causes of the subsequent failure of mechanical components [11][12][13]. Therefore, it is of great significance to carry out theoretical and technical research on the nonlinear clearance control of servo systems.…”