Modification and Its Application of Identification Inputs for Hydraulic Arms

On the Uncertainty Analysis via Low Frequency Inputs for Hydraulic Cylinder Dynamics

“…From the nonlinear nominal model ( 1), ( 2) and (3), we obtain: (7) We can see that Equation ( 7) can be a system of linear equations in terms of unknown physical parameters. The motion equation for the mechanical system is given as: (8) with…”

“…In fact, Fig. 2 shows an example of the input and outputs in the low-frequency domain (<1.0 Hz) of the previous setup 8) . Indeed, just before three seconds, the piston collides with an end (the rod side) and then the input-output behavior is not linear anymore.…”

“…The Bode diagram of the linearized model ( 5) is obtained from the non-dimensional transfer function (6), in which physical parameter identified from the physical parameter identification experiment. The Bode diagram from the experimental setup is obtained by observing and measuring the input-output behavior under modified sinusoidal inputs 8) within low frequency domain of identification inputs 8) :…”

“…where the sinusoidal amplitude A u = 1.0×10 −4 m, and sinusoidal frequency f u = {0.5,0.6,0.7,0.8,0.9,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0, 10}Hz. The DC component −0.0266 • A u • (A + /A − ) 2 = −4.4×10 −5 m is added to the standard sinusoidal input (4) 8) . The Bode diagram (input: spool displacement, output: driving force) from the experimental setup is obtained using the modified identification input and that of the linearized model ( 5) from ( 6), respectively.…”