A. Oscillograms
An oscillogram is a printout from a digital oscilloscope. Figures VI.A.1 to VI.A.4 illustrate oscillograms taken during the experimental trial runs. The oscilloscope used is a Siglent SDS1000X.
Payload moving towards right solenoid
The oscillograms in Figures VI.A.1 and VI.A.2 are taken when the payload is traveling 1 centimeter to the right. In both figures, the range of time is for the 200 milliseconds surrounding the transition.
Figure VI.A.1: Oscillogram of the inputs to the voltage-controlled current sources (VCCS) for both solenoids.
Figure VI.A.1 illustrates the traces of the voltage inputs to the VCCS for both the left and right solenoids. The blue trace represents the right solenoid while the red trace represents the left solenoid. Note that the right solenoid pulls the payload first to get it moving to the right. The left solenoid then exerts a pulling force on the payload to get it to stop. Also, note that when the solenoid is on the right, the left solenoid must have a higher input to exert the minimum tension force on the payload.
Figure VI.A.2: Oscillogram of position and input to one solenoid.
For Figure VI.A.2, the red trace refers to the potentiometer output, which is the measurement of the payload displacement. The leftward direction is positive on the potentiometer. The blue trace refers to the input to the VCCS that drives the right solenoid.
Payload moving towards left solenoid
The oscillograms in Figures VI.A.3 and VI.A.4 are taken when the payload is traveling to the left.
Figure VI.A.3: Oscillogram of the VCCS inputs for both solenoids.
Once again, Figure VI.A.3 illustrates the traces of the voltage inputs to both solenoids. Note that the left solenoid pulls the payload first to get it moving to the left. The right solenoid then exerts a pulling force on the payload to get it to stop. When the solenoid is on the left, the right solenoid must have a higher input to exert the minimum tension force.
Figure VI.A.4: Oscillogram of position and input to one solenoid.
For Figure VI.A.4, the red trace refers to the payload displacement. The blue trace refers to the voltage input for the right solenoid. Note that the force generated by the right solenoid initially drops to zero before it goes high to stop the payload from moving.