Research On Control System Of Auto-Following Robot-Car

With the rapid development of science and technology,various intelligent robot products are gradually put into use,which is changing people's life."Following" robot is an important part of them.As a special product,"Auto-following robot-car" has been put forward very early.A few companies at home and abroad have released this kind of product,and most of them are based on active positioning,in which the followed target needs to carry a signal transmitter.This method maybe has many inconveniences in the practical application,also with that its price is expensive,so it can not be widely used at present.In order to make auto-following robot-car to be used widely and provide convenience for people's life.In this dissertation,a new method is presented,which can locate the followed target and identify obstacles with an ultrasonic array.In this design,the possible situations of the followed target and obstacles in front of the robot-car are summarized and analyzed,and the corresponding control strategies are given.Also,the error reasons of ultrasonic ranging are analyzed and the solutions are given.Using the FPGA chip as the controller of the robot-car,a whole control system is designed,which is mainly divided into three parts: the main control unit,the detection unit and the motion unit.The detection unit includes five ultrasonic detection sensors,which realizes the detection of the target and the obstacles in front of the robot-car.Following control is based on the incremental digital PID.The distance between the followed target and the robot-car is compared with the set distance,and then the duty cycle of PWM wave is adjusted in real time by FPGA to achieve tracking control.The robot-car is drived by two DC motors mounted on the front wheels,and the steering control is achieved by controlling the difference in speed between the two motors.In addition,UART debugging module,voice broadcast module and other auxiliary modules are also included.The designed auto-following robot-car has the characteristics of sensitive response,and low cost,so it is easier to spread to people's daily life and has application value.