Design And Implementation Of A New Unmanned Express Delivery Vehicle

In the past ten years,the rapid growth of online shopping has promoted the vigorous development of China's logistics industry.At present,the number of express delivery has increased more than ten times compared with ten years ago,but the delivery method of express delivery is still extremely dependent on human transportation.Therefore,electric-driven car,which may possibly replace manpower in the future,can be widely used in urban unmanned express delivery.The car can not only solve the "last mile" problem of express delivery from the express outlet to the user in a short period of time,but also better cope with the problem of rising labor cost and urban pollution in the future,which has great application prospects.In this paper,a new wheeled mobile platform is designed for the practical needs of small steering angle and large storage capacity.The platform is driven by two hub motors and differentially steered,and the two driven wheels are free to steer and rotate under the influence of the drive wheels.The new mobile platform not only retains the advantages of the wheeled structure,but also can accommodate large capacity lithium batteries and 16 express boxes in a limited space due to the elimination of complex deceleration and differential mechanical structures.After a single charge,the vehicle can carry 30 kilograms of goods for 20 kilometers.At the same time,the two-wheel differential steering mode makes the mobile platform turn more flexible,and can be turned around in a narrow road or even indoors.In this paper,the traditional two-wheel drive mobile platform model is further studied based on the double closed-loop DC brushless motor model.The effective moment of inertia of the hub motor is simulated by the load and equivalent moment of inertia of the drive wheel.Then the complete motion model of the express car is obtained through the simplified model of the double closed loop speed control and the model parameters of the genetic algorithm.The dynamic response of the drive wheel reduces the difficulty of future debugging.In the experimental verification phase,the single-chip microcomputer is used to perform Kalman filtering on the speed value returned by the encoder,which effectively reduces the interference of noise on the control program.Then the control effects of incremental PID and fuzzy PID on the motion of the hub motor are compared.Based on this,a new control algorithm combining the left and right drive wheels is designed.The mobile platform not only responds quickly to control commands,but also operates stably when the road surface is uneven.