3. Caterpillar Locomotion - Virginia Tech

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Chapter 3 – Caterpillar Locomotion 146

3. Caterpillar Locomotion

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3.1 Introduction

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3.1.1 Previous Studies of Animal Locomotion

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Left 3

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Figure 3.1 — Gait Diagram of a Cockroach's "Tripod Gait". (Adapted from Wilson, (1966).)

3.1.2 Caterpillars

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Figure 3.2 — Side View of a Standing Tent Caterpillar

Figure 3.3 — Side View of a Pitching Tent Caterpillar

Chapter 3 – Caterpillar Locomotion 151

Figure 3.4 — Bottom View of Turning (Yawing) Tent Caterpillar

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3.2 Experimental Program

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3.2.1 Videotaping Caterpillar Locomotion

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3.2.2 Determination of Workspace

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Chapter 3 – Caterpillar Locomotion 156

Table 3.1 — Approximate Physical and Locomotion Characteristics of Eastern TentCaterpillars

Note 1: This may not have been voluntary. Also note that this is pitching up; negative pitch was not

measured but is believed to be much smaller.

Note 2: After the experiments, when the caterpillars were released, they appeared to move much

faster than this 'maximum'. Unfortunately, this was not documented on video and so their

true top speed is unknown. The caterpillars' decision to finally demonstrate their speed

capabilities may be attributable to their pleasure at finally being released from the jar, or

more likely, the pavement was hot.

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Chapter 3 – Caterpillar Locomotion 157

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Chapter 3 – Caterpillar Locomotion 158

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(Note that the segment numbering scheme used here is different than that used inentomology literature.)

Chapter 3 – Caterpillar Locomotion 159

Figure 3.6 — Tent Caterpillar Gait Diagram

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Chapter 3 – Caterpillar Locomotion 161

Figure 3.7 — Eastern Tent Caterpillar Climbing a Large “Hill”

3.3.2.2 Crossing Large Obstacles

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3.4 Application to Robot Design

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Chapter 3 – Caterpillar Locomotion 164

3.4.1 Legs

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3.4.2 Actuation Units

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3.4.3 Linear Actuators

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Chapter 3 – Caterpillar Locomotion 165

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Figure 3.8 — Comparison of Compound Linear Actuator and Simple Linear Actuator

3.4.4 Motion Programming

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Chapter 3 – Caterpillar Locomotion 166

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3.4.5 Payload Boxes

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Chapter 3 – Caterpillar Locomotion 167

Figure 3.10 — A Crawling Vehicle Using Payload Boxes with Rounded Tops

3.5 Chapter Summary

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