Tham khảo tài liệu 'crc press mechatronics handbook 2002 by laxxuss episode 3 part 1', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Hypothesizing a bipolar reference signal it can be assumed that the range Vref 0 corresponds to the supply-user connection while the field Vref 0 corresponds to the user-discharge connection. The appropriate equation of flow above must be rewritten in the same way. Calculation of the conductance of the flow proportional valve is made considering the static and dynamic link between the reference voltage Vref and the opening of the passage aperture A v in accordance with modeling of the second order of the type J2a d-A 2 s dAV s2Av KSVf n IV s n Id dt dt where z is the damping factor ơn is the valve s natural frequency and Ks is its area static gain. Assuming a static relation of the linear type between the opening Av and the conductance C as an initial approximation we get C KAv m KvVref where Kv is the flow static gain of the valve function of the maximum conductance Cmax and of the maximum value of the reference voltage Vref max Kv C-- v ref max The complete dynamic relation between reference voltage and conductance is therefore d C dC 2 2 - 2 Sn 7- s C Kc s vref n n c n Id dt dt The nonlinear model of the pneumatic servosystem with the position reference xsel and the force disturbance Fe as inputs is made up of a nonlinear system of nine equations of order eight overall of the type a Cj Q vri j t order 2 conductance of valve Vj see b C2 C2 v . 2 t order 2 flow rate of valve Vj see c Gj Gj Cj Pj order 0 flow rate of valve Vj see - d G2 G2 C2 P2 order 0 flow rate of valve V2 see - e Gj Gj Pj P j x x order j continuity chamber j see f G2 G2 P2 P 2 x x order j continuity chamber 2 see g x x Fe Pj P2 x order 2 piston equilibrium see h vref j ref j xset xret order 0 Vj valve control i vref 2 ref 2 xset xret order 0 V2 valve control If we want to carry out a linear analysis it can be assumed that the equations a b g h i are already written in linear form. As far as the flow rates of valves c .
