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Trapezoid Profile Calculator

Run the Trapezoid Profile Calculator MicroSim Fullscreen

You can include this MicroSim on your website using the following iframe:

<iframe src="https://dmccreary.github.io/robot-arm/sims/trapezoid-profile-calculator/main.html"
        height="642px" width="100%" scrolling="no"></iframe>

Description

Set a distance, a speed limit and an acceleration limit and watch the speed graph of a joint move change between a trapezoid and a triangle. Then calculate the times and the peak speed for six problems. Used in Chapter 11.

The graph shows the speed of one joint against time. The joint speeds up at the acceleration limit, cruises at the speed limit and slows down at the same rate. If the distance is shorter than v² / a, the joint never reaches the speed limit and the graph is a triangle. The panel shows the working with your numbers.

The formulas are from the Chapter 11 section "Velocity Profiles and the Acceleration Limit". The values in the problems are illustrative, and problems 1 to 5 use the chapter's two worked examples.

Lesson Plan

Grade level: Middle school and up (age 12+). Time: 10 to 15 minutes.

  1. Explore. Start with D = 90, v = 60 and a = 120. Read the speed-up, the cruise and the total time off the panel.
  2. Find the change. Make the distance shorter, five degrees at a time. At what distance does the trapezoid become a triangle? Compare it with v² / a.
  3. Change one limit. Raise the acceleration limit. What happens to the ramps, and what happens to the cruise speed?
  4. Six problems. Switch to Six problems. Test D ≥ v² / a first, choose the formula, work out the number and type it. You get one try for each.
  5. Think about it. Why is the total time longer than the distance divided by the speed limit?

Specification

The learning objective, evidence of mastery and content for this MicroSim are specified in Chapter 11: Moving the Arm: Trajectories, Grippers, and Teleoperation.