Research On The End Position Control Strategy For Multi Degree Of Freedom Of Pneumatic Manipulator Above Rough Ground

With the advent of the era of industrial 4.0,more and more robots appear in various fields,such as welding robot,handling robot,painting robot,picking robot and so on.Some of them are applied robot need to work under special conditions,usually explosion protection and anti-corrision are required.At the same time,along with the rapid development of electronic technology,the pneumatic servo system,espically the pneumatic servo position control system's precision are improved further.On the other hand,the pneumatic system has good flexibility,and has a clean,safe,light and relatively low cost,which make it suitable for working under some special circumstances.The pneumatic manipulator with the advantages of simple structure,no pollution,high cost performance is suitable for agricultural harvest and spraying.Pneumatic system has strong nonlinear and time-varying parameters,the low stiffness,time lag makes in a precise positioning control is diffcult to achieve the ideal effect.Specially,the transient mass flow rate equation model are uncertain and with strong nonlinearity,the quality parameters are uncertainty and the pressure equation is unknow nonlinear.In addition,with the driving force of the cylinder friction is bigger,the friction modeling is diffcult and the linearization is complex,the pneumatic system of low stiffness and the reverse of the friction force restrict the pneumatic servo system trajectory tracking precision.This paper designs a kind of multi degree of freedom of pneumatic manipulator,and six degree parallel platform to simulate rough ground environment.However,control strategy has to be modified when the pneumatic robot worked on a walking machine.So research on the position control strategy for pneumatic robot above rough ground has practical application.In this paper,a 6-DOF electric platform has been built for simulating rough ground and a pneumatic robot has been built.Through co-simulation by Simulink and AMESim,the effectiveness of pressure compensation PID control method has been proved.The corresponding research work has been done for this manipulator,the main research work is presented as follow:Firstly,this paper designs a kind of multi degree of freedom of pneumatic manipulator.The prototype is designed with UG software and the two dimension drawings are produced in AutoCAD.The 6-DOF parallel platform is designed to simulate the rough ground,whose prototype is designed in UG and the kinematic analysis is done in Matlab/Simulink for its routine solution expression.Then,the pneumatic servo system is built to drive the manipulator and the essential force simulation is done.Thus,the pneumatic components are choosen,such as swinging cylinder,linear cylinder,proportional directional valve and air handling unit,etc.Besides,according to the linear hypothesis,this paper analyzes the typical valve controlling cylinder system transfer function and the block diagram of valve inlet pressure independent control system.Moreover,the link coordinate for pneumatic manipulator is established by D-H method.The kinematic modeling and analysis is based on the D-H coordinate,and the Jaccobi matrix is obtained.Besides,Matlab is used to figure the 3-D work space of the manipulator and UG modeling is used for kinematic simulation.Futhermore,the pneumatic system model is built in AMESim due to the real parameters for all the components choosed in prior chapter.Matlab/Simulink is known for its convenient and fast in compile control strategy,and the PID algorithm and fuzzy controller is built in it.Then the co-simulation is worked between these two software to simulate the correctness of the control algorithm.Both PID algorithm and inlet pressure independent fuzzy control algorithm are tested and the results are achieved.At last,the experimental platform combined with both multi degree of freedom of pneumatic manipulator and 6-DOF parallel platform is built.The sensors are equipped and PC is used to control the whole system.LabVIEW is installed in PC to build the control sofeware.Thus,the experiments are conducted and the data are processed to reveal the effectineess of certain control strategy.