Motion Analysis And Control Of Cutting Arm Of The Boom-type Roadheader

With the continuous development of science and technology,unmanned and intelligent coal mining has become a key factor in achieving sustainable development in the coal industry.The boom-type roadheader plays a vital role in the coal mining process,and its intelligent control can increase work efficiency,reduce labor,ensure coal mining safety,and improve the forming quality of tunnels.This paper studies the motion control of the cutting arm,one of the key technologies in the intelligence process of the boom-type roadheader.For the purpose of position control of the cutting head,the research includes the kinematics modeling of the cutting arm,the modeling of the hydraulic control system and the control method of the cutting head position under the interference of external load force.The main work and conclusions are as follows:(1)The kinematics model of the boom-type roadheader’s cutting arm is established.The movement of the cutting arm includes the horizontal swing,the vertical lifting,the telescopic of the cutting head,which can be equivalent to a three-joint series mechanical arm.According to the theories of robotics,the forward kinematics model of the cutting arm was established based on the D-H parameter method;the inverse kinematics equation of the cutting arm was derived by using the geometric method.Through the spatial geometric relationship of the cutting arm,the mathematical relationship between the swing angle of the cutting arm and the stroke of the driving hydraulic cylinder is obtained.The 3D model of the main working mechanism of the boom-type roadheader is established,and the correctness of the kinematics model is verified by simulation.(2)The hydraulic control system model of the cutting arm is established,and the PID and fuzzy PID controllers are designed.According to the principle of the hydraulic transmission,the mathematical models such as the valve-controlled asymmetric hydraulic cylinder and the electro-hydraulic proportional reversing valve are derived,and the model of the hydraulic control system of the cutting arm is established.In order to improve the control performance,a PID controller and a fuzzy PID controller are designed.The simulation results show that under the PID control,the rise time of the output response is reduced from the original 2 seconds to 0.4 seconds,which improves the response speed and anti-interference ability of the system,but the stability of the system has decreased.Under the fuzzy PID control,the response speed of the system output is faster than that of the PID control,and the overshoot is reduced by half,which improves the stability of the control system.(3)The position control method of the cutting head of the roadheader is designed.Based on the kinematics equation of the cutting arm and the mathematical model of the hydraulic control system,a simulation model for the position control of the cutting head of the EBZ230 roadheader is established.The position control of cutting head under different external load conditions is simulated.The results show that under fuzzy PID control,the trajectory of the cutting head can track the target trajectory.Without external load interference,the tracking error of the cutting head’s trajectory is kept within 2cm;under the condition of random external load force interference,the tracking error of the cutting head’s trajectory is kept within 5cm,which meets the requirements of the actual cutting operation of the roadheader.