Pre-lab 5 - UBC Mechanical Engineering

MECH 421: Mechatronics System Instrumentation
The system parameters are listed in Table 1.
Pre-Lab Assignment
1. Initial Model:
Parameter
Value
J1 – Idle Shaft Inertia
0.001069 Kg-m^2
J2 – Drive Shaft Inertia
0.001089 Kg-m^2
J3 – Gearbox Inertia (Output Side) 0.0007142 Kg-m^2
J4 – Motor Inertia
0.0001363 Kg-m^2
M1 – Total Mass of Belts
3.861 Kg
R1 – Pulley Pitch Radius
0.03183 m
Amplifier Gain
0.6195 A/V
Motor Torque Constant
0.193 Nm/A
Gearbox Reduction Ratio 10:1
Encoder Resolution (After
Quadrature Decoding)
1440 Counts/Rev
Table 1 – Conveyor System Parameters
Based on the information in the lab description and the parameters supplied, draw
a block diagram for the whole system assuming an infinitely stiff shaft coupling,
with input Vc in unit [V] and output drive shaft position in unit [revolution].
Establish a model for the whole system, and derive the transfer function from Vc
to . Draw Bodes plots of your transfer function.
2. Refined model:
Figure 4 shows the system frequency response experimentally measured by Darya
from Vc[V] to [rev]. Compare the Bode plot of your first model in part 1 with
Darya’s measurement result. Discuss and explain the differences. Based on this
measurement result, establish a new refined physical model which fits the
experiment result as much as possible. Draw Bode plots of your refined model.
Try to give an intuitive physical interpretation of the dynamics exhibited from the
frequency response, and relate the measurement results to design parameters of
the system. (HINT: remember the two mass coupled system. Is the shaft coupling
really infinitely stiff? )
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