| Modern forestry operation tasks are facing mechanization and intelligence,and higher requirements are put forward for field operation robots to be able to adapt to variable and complex field environments as well as various climatic environments.The operation robot installed above the driving vehicle is affected by the complex terrain in the field,which is easy to cause the loss of the operation object recognition and the difficulty of target feature extraction,so ensuring the operation accuracy and stability of the operation robot has become an important issue for the intelligent vehicle-mounted operation robot.In this paper,the dynamics modeling and control technology of the system is studied in depth with the vehicle-mounted operation robot as the research object,mainly focusing on the following four aspects:(1)Firstly,the overall design scheme of the vehicle-mounted operation robot is introduced,which is divided into two modules: the load-bearing vehicle system and the operation robot operation platform system,and the system composition and functions,working principles,and design requirements and parameters are described in detail.The all-terrain vehicle provides advanced control architecture for speed control,trajectory tracking and required navigation functions;the rotating joint configuration of the two-degree-of-freedom operation robot is slew-pitch,which is flexibly operated through PID closed-loop control.(2)Then the mathematical model of the operational robot is established based on the Lagrangian method,and the dynamics of each joint of the operational robot is analyzed to obtain the influence law of the controlled object torque on the joint motion;the forward and reverse kinematics of the operational robot are analyzed to obtain the relationship between the end position posture and the position of each joint of the operational robot,which provides a theoretical basis for the PID control method in the servo control system of the operational robot.This provides a theoretical basis for the PID control method in the servo control system of the robot.In addition,the inertial stability and spatial positioning conversion characteristics of the gyro manipulator platform are studied,and the switching control strategy under the non-inertial position control mode and the master-slave control structure under the inertial rate control mode of the gyro manipulator platform are designed,and the target conversion law is summarized.The overall provides the theoretical basis for the next step of operational robot simulation.(3)Secondly,a mathematical model of the steering system of the all-terrain vehicle was established,and the positioning tracing of the all-terrain vehicle was achieved through the steering control with the rate as the controlled object and the speed control with the distance and remaining time to the destination.The mathematical model of the suspension system of the all-terrain vehicle was established,and the suspension system vibration control law was obtained by implementing PID control in the system for the difference between the spring mass velocity and the non-spring mass velocity.It provides the theoretical basis for the next step of target identification and positioning and vibration control of the vehicle-mounted operation robot.(4)Finally,both modeling and simulation of the vehicle-mounted operational robot system were carried out in OpenModelica software.For the modeling aspect,a two-degree-of-freedom(azimuth and pitch)mechatronic model library was developed to quickly establish the dynamics model of the operating robot;a complete vehicle system was assembled,and the digital grade road surface on which the vehicle travels was combined with the vibration model of the driving system to construct the dynamic random load time course of the vehicle system under all levels of road surfaces and gears as well as the road load spectrum for the subsequent vehicle-mounted operating robot The purpose is to establish the model of gyroscope based on Modeilca language,and measure the motion control process of vehicle-mounted work robot through gyroscope platform.The aim is to establish the model of gyroscope based on Modeilca language,and measure the attitude of the motion control process of the vehicle-mounted operation robot through the gyroscope platform.Overall the pitch and azimuth angles achieved by the two-degree-of-freedom robot arm are more capable of rapid convergence and stability,both of which can quickly approximate the theoretical trajectory curve and make reasonable compensation for the angular deviation during robot arm motion,with better control effects;case verification shows that the change trend of azimuth and pitch angle response using modelica simulation is consistent with the change trend of the case using matlab simulation results,and the Compared with the matlab/adams joint control simulation study,the modelica component-based model library study,which integrates the control system and mechanical system in one software,brings greater convenience to the study of turret system dynamics and control system.Therefore,modelica can be used for system modeling and PID control strategy simulation of vehicle-mounted operational robots. |
