Control Of A Path Following Caterpillar Robot Based On A Sliding Mode Variable Structure Algorithm

Crawler chassis walking mechanism has outstanding advantages of high mobility,high off-road performance,high flexibility,strong environmental adaptability and high carrying capacity.Especially in the field under complex terrain conditions and harsh environment,crawler chassis walking mechanism has higher adaptability and passing ability than wheeled walking mechanism.But in the process of the actual driving because the crawler traction coefficient is unknown,complex factors such as soil conditions harsh environment will cause walking tractor chassis institution deviates from the desired trajectory,precise driving along a given path,avoid walking tractor chassis institution deviates from the given trajectory appears out of control,is walking tractor chassis agencies in various operating environment(such as monitoring,mechanical spraying herbicides or pesticides)in one of the most important tasks.But walking tractor chassis agency with complex track-ground interaction interface,and crawler chassis two crawler travel mechanism exists between different trajectories,greatly increasing the difficulty of crawler travel mechanism chassis control,using the traditional control methods,such as control,as a result of the existence of timevarying parameters can reduce the control performance,this is due to the traditional control algorithm is not according to the soil of unknown terrain parameters to adjust the control parameters,the sliding mode variable structure control algorithm for the uncertainty of the controlled system,external disturbances and parameter perturbations can adjust in time,Under the influence of external disturbance and uncertainty,it can reliably track the expected time-varying trajectory in an exponential convergence way and improve the fault tolerance of the control process.Therefore,sliding mode variable structure control is suitable for the traveling control of crawler chassis mechanism.In this paper,based on the previous research,a differential control method for crawler chassis system with double motors is designed based on the sliding mode structure.The specific contents of this paper are as follows:First of all,this paper has designed and produced a double motor drive crawler chassis system,pedrail around respectively for brushless dc motor drives the driving wheel drive,through the control about crawler double motor drive motor speed to achieve differential control caterpillar chassis system,using SICK radar sensor scanning double motor drive crawler chassis system environment for the established path,using industrial computer to control,the design of double electric crawler chassis system is installed on the thermal spraying fog machine is suitable for plant protection field operations system,at the same time crawler chassis system of double motor driving principle is analyzed,On this basis,the kinematics model of the tracked chassis system with two motors is established.Then,the sliding mode variable structure control algorithm is introduced,and based on the synovial variable structure algorithm designed a double electric crawler chassis system differential control method,and set up a control algorithm in / software simulation program,and has carried on the simulation test,the preliminary design of double motor is proved by the crawler chassis system differential control method is feasible.Next,in the multi-body dynamics simulation software,the dynamics model of the tracked chassis driven by double motors was established.Meanwhile,the control program of the joint simulation test was built in /,and the joint control simulation test was carried out.Under conditions closer to the actual environment,the performance of tracked chassis controlled by synovium variable structure control and traditional PID control is compared.Based on the simulation structure,the tracked chassis controlled by synovium variable structure control is more stable and more adaptable to complex drivingFinally,the article simulated conditions of corn roots of double motor drive crawler chassis system driving test,verify the square design in this paper based on the feasibility of synovial variable structure control algorithm,double motor drive crawler chassis in soft soil surface set of corn roots straight driving test,the effect of the experiment shows that adopting synovial variable structure control algorithm of double motor drive crawler chassis is able to drive along the given trajectory,does not appear significantly deviate from the track and out of control phenomenon.