Design Of Wheeled Robot Speed Control System Based On Fractional Sliding Mode Internal Model

Wheeled robots have the advantages of high speed and high efficiency,and are widely used in industrial,medical,agricultural,and inspection fields.With the increasing use of wheeled robots,the operating environment of wheeled robots has become more and more complicated.Brushless DC motor(BLDCM)has the advantages of high torque and high efficiency,and is widely used in wheeled robot drive control.For current wheeled robots,there are problems such as slower speed adjustment,poor anti-interference ability,and internal jitter.It affects the control accuracy during the operation of the wheeled robot and reduces the accuracy during the work.In view of the above problems,the optimization of the brushless DC motor drive control system for wheeled robots has been studied.Firstly,in order to make the wheeled robot more flexible,the turning radius is smaller.A steering motion model of a wheeled robot was established.Through analysis,the front wheel steering motion model and the four-wheel differential steering motion model were compared.Four-wheel differential steering was selected as the steering control system of the wheeled robot;The mathematical model and working principle are introduced in detail.Then,in order to solve the problems of large speed balance overshoot and long adjustment time for the brushless DC motor drive control system of wheeled robots,based on the original fuzzy PID control algorithm,a combination of anti-integral saturation and variable-speed integral algorithm was used to control the fuzzy PID.The integral term of the controller is improved.At the same time,in view of the existence of system chattering in sliding mode control,a new fractional sliding mode internal mode control strategy is proposed based on the fractional-order integral operator and internal-mode control,which is applied to the wheeled robot brushless DC motor drive control system.Secondly,according to the motion mode of the wheeled robot,a four-wheel differential motion model is established using Matlab / Simulink and Carsim,and the signal transmission between the drive system of the wheeled robot and the vehicle model is completed through the interface settings of Simulink and Carsim.Based on Carsim's unique pavement input response,the wheeled robot is compared and analyzed for the stability of the vehicle's speed during walking on different pavements.And select the overshoot,rise time Tr and time multiplied by the absolute error integration criterion ITAE for evaluation.The experimental results show that the fractional-order sliding mode internal model controller has strong anti-interference ability to external interference,fast speed response,small fluctuation of speed response curve,can reach the set speed quickly,and run smoothly at the set speed.Finally,according to the operation mode of the wheeled robot,the STM32F103VCT6 is selected as the main controller,and the hardware circuit design of the signal output circuit and feedback detection is completed,and the software control such as the main strategy control program and the control program of the adjustable speed motor design.