TECHNOLOGY-BASED LAB ACTIVITIES

DEVELOPING THE MODEL
A plot of the proper position of a robotic arm for a specific task can be generated
by manually moving a robotic arm through the required task while the arm is
monitored with a motion detector. The motion detector can collect data on the
position of the arm at small time intervals, and a graphing calculator can then be
used to present the data in graphic form. Once a graph is generated and stored, it
can serve as a program—a set of instructions that can be repeated over and over
again.
Before starting this activity, do the following exercises:
1. A robotic arm may have to move back and forth at different velocities and
into different positions to complete a single task. To familiarize yourself
with how this kind of information might look when stored as a graph,
sketch a graph of distance versus time for each of the following situations:
a) The robotic arm is at rest.
b) The robotic arm is moving away from the reference point at a constant
speed.
c) The robotic arm is moving toward the reference point at a constant
speed.
d) The robotic arm is accelerating away from the reference point, starting
from rest.
2. When you program a robotic arm, information about the speed at which
the arm moves is important. To familiarize yourself with how this kind of
information might look when stored as a graph, sketch a graph of velocity
versus time for each of the situations described above.
PROCEDURE
Part l Generating Graphs
1. Lay out an area that represents the positions over which the robotic arm can
move. Place the motion detector near the edge of a table, and point it
toward an open space at least 3 m long. Secure the motion detector with a
bracket or clamp. Use short strips of masking tape on the floor to mark the
origin and distances of 1 m, 2 m, and 3 m from the motion detector.
2. Connect the Vernier motion detector to the SONIC port of the CBL unit.
Use the black link cable to connect the CBL unit to the calculator. Firmly
press in the cable ends.
3. Set up the calculator and CBL for the motion detector.
• Start the PHYSICS application and proceed to the MAIN MENU.
• Select SET UP PROBES from the MAIN MENU.
• Select ONE as the number of probes.
• Select MOTION from the SELECT PROBES menu.
4. Set up the calculator and CBL for data collection.
• Select COLLECT DATA from the MAIN MENU.
• Select TIME GRAPH from the DATA COLLECTION menu.
• Enter “0.1” as the time, in seconds, between samples.
• Enter “99” as the number of samples. The CBL will collect data for about
10 seconds.
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2 HOLT PHYSICS Technology-Based Lab Activities