Research On Lateral And Longitudinal Control Of Self-driving Vibratory Roller

Application of self-driving technology in the field of engineering machinery is highly expected to decrease driver’s fatigue and speed up construction schedule.Single drum vibratory roller is widely used in road and dam construction.Vibratory roller usually works under the influence of road condition,self-vibration and hydraulic steering response delay.Roller is a center-articulated vehicle and its front drum and rear wheels are fixed to an active revolute joint,which brings challenge to accurate trajectory tracking.For the purpose of achieving lateral and longitudinal control,a selfdriving roller prototype is reconfigured.This paper discusses the kinematic characteristics of pivot and driving steering and proposes the extended kinematic model under the effect of slip angle.The adaptive pure pursuit and nonlinear ADRC feedback algorithm improve the capacity of resisting disturbance and adaptive ability.The research work consists of the following four parts:1.The prototype is equipped with information acquisition system,communication and control system.Steering motor and handle motor is used to realize direction and speed control.The experimental platform provides basic data for lateral and longitudinal control research.2.The steering action is achieved by changing the articulation angle between the front and rear frame using two hydraulic cylinders,which is called torsion effect.In real environment,roller movement is affected by road friction,tire deformation and self-inertia.Deviation from ideal motion can attribute to slip angle α/β and extended kinematic model under the effect of slip angle is proposed.The torsion and slip effect is described as moving disturbance.Hydraulic steering response delay and uncertainty is seen as internal disturbance.3.Adaptive pure pursuit algorithm look for preview point in desired trajectory,which provides desired orientation and road curvature for control.The relationship of drum heading,articulation angle and steering angle is analyzed.A dual loop ADRC lateral controller is used to estimate and compensate the uncertainties.Model information is included in the design of extended state observer,which aimed to reduce observer burden.Fal nonlinear function realize the coordination of error and gain.Desired speed is decided by preview point road curvature in longitudinal control,which can reduce overshoot in case of large curvature turn.4.Three kinds of desired trajectory is tested in simulation environment.Simulation results show that average distance error is about 0.19 m in straight line case,0.32 m in circular trajectory case and 0.38 m in curved trajectory case.In campus test site,straight line tracking experimental results show that average distance error is 0.22 m.The simulation and experimental results demonstrate the anti-disturbance ability of the proposed method.