Trajectory tracking sliding mode control system and control method for spraying mobile robot

Abstract

The invention discloses a trajectory tracking sliding mode control method for a spraying mobile robot. The method comprises the following steps of: performing mechanism analysis on a mobile robot, and establishing a mobile robot kinematic model with non-integrity constraint; establishing a controlled object mathematical model of each branch controller of a wheeled mobile robot provided with a motor driving shaft disturbance term; identifying a traveling path by utilizing a computer vision system, and determining an expected motion track of each branch driving motor according to the kinematic model deduced in the previous step; detecting the rotating speed of the motor, calculating the actual motion angular velocity and actual motion angular acceleration of left and right driving motors of the mobile robot, and calculating the deviation and deviation derivative between the expected angular velocity and the actual angular velocity of each driving motor; establishing a sliding mode switching function which meets the speed control requirement of the driving motor; determining the sliding mode controller control quantity of the left and right driving motors of the mobile robot on the basis of the sliding mode surface function s; and respectively transmitting the control quantity of the motor of the mobile robot to the left and right driving motors.

Description

technical field [0001] The invention relates to a trajectory tracking control of a mobile robot, in particular to a construction method of a sliding mode controller for the trajectory tracking control of a two-wheel drive spraying mobile robot in a greenhouse environment. Background technique [0002] Since the 1970s, China has gradually promoted plastic greenhouse planting technology and achieved significant economic and social benefits. Today, China has become the largest producer of greenhouse crops. However, there is still a certain gap between my country's greenhouse production management level and automation level compared with advanced countries. In terms of greenhouse production equipment, manual sprayers are still used for crop application. In order to effectively improve the utilization rate of pesticides, reduce labor intensity, and reduce the harm of pesticides to operators, it is necessary to improve the automation level of greenhouse production equipment in my...

AI Technical Summary

Problems solved by technology

In addition, factors such as temperature, humidity, illuminance, ground flatness, and manufacturing errors of driving wheels in the greenhouse environment, as well as the presence of disturbances such as certain crops, greenhouse skeletons, pipes, and road appendages, make it difficult for the above-mentioned PID control method to control the robot along the planned path. The actual trajectory is easy to deviate from the ideal operation route, so there will be a large area of ​​heavy spraying and missing spraying in the working area

[0006] In addition, reviewing domestic patents on the control of wheeled mobile robots shows that most of the patents on mobile robot control are the structural design of the control system. The accuracy of information collection will inevitably affect the trajectory tracking accuracy of greenhouse mobile robots

[0007] It can be seen from the above-mentioned trajectory tracking control related technologies of greenhouse mobile robots that the existing research has achieved some results, but there are certain limitations.

The fuzzy control method lacks self-learning ability, and the fuzzy control rules cannot be adjusted online in the mobile robot trajectory tracking control system, and there is a certain degree of subjectivity in the selection of the membership function of the input and output, and the adaptive ability is limited, so it is difficult to obtain the ideal trajectory. Tracking effect. In addition, fuzzy rules depend on the experience of the operator. For the control system of the greenhouse spraying mobile robot with multiple input and output, the reasoning rules and fuzzy control tables are more complicated; the PID control method is only for linear system or simple Non-linear systems are applicable, but for complex greenhouse spraying mobile robot systems with multi-variable, highly nonlinear, uncertain factors and disturbances, the control effect is not ideal; the main problem of the sliding mode control based on the Backstepping method lies in the controller’s The structure and design process are complex, and the robot is required to provide sufficient acceleration, which is difficult to meet the real-time requirements of the control of the greenhouse spraying mobile robot

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