Houston - Landing gear modifications

Task Description

The current Houston landing gear has tipped over several times during landing in areas of high wind. The objective of this task is to modify the landing gear to prevent the drone from tipping over easily.

Constraints

Relevant Contacts

Assignees

Task Progression/Updates

Author: @Agapa Goombs and @Sam Wong updating Date: 2024/03/04

Initial Ideas:

Due to the requirement to decrease the height of the drone as well increase the footprint of the landing gear, the decision was made to try to increase the angle of the landing legs while retaining the mounting for the top plate connection.

A benefit of this design is that it would fulfill the defined constraints while not increasing the the weight by a significant margin. A potential drawback would be a redesign of the bottom mounting plate with extensions to the corners to connect to the landing legs that would be farther out.

A spacer to connect the plate to the arm could but used but may present some structural concerns. Not only does this increase the complexity of assembly, it also creates structural weakness in the event of crash. If installed incorrectly, it can become unstable on the ground due to different angles of the landing legs.

Author: @Agapa Goombs and @Sam Wong updating Date: 2024/03/06

Version 1:

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Figure 1: Current Design (Version 1)

As seen in Figure 1, the current design fulfills the rigidity constraint due to the flange bends on each side of each leg which increase the strength of the landing legs. Alongside this, their current design allows for the connection into the top platform with the arms. Consequently, the decision was made to iterate on this design as opposed to make drastic changes, leading to more more integration effort required.

The idea was to retain the distance between and orientation of each of the screw holes at the top of each leg to allow it to screw into the existing top platform. This is a pattern forms a square with a side length of around 110 mm which would need to be maintained in any new designs.

The design constraints require a lower height, lowering the CG, and greater landing gear footprint with a mass increase of at most 300 g. To achieve this, the decision was made to increase the angle between the top platform and the landing legs from 110 degrees (current) to 125 degrees. This resulted in Version 2 as seen in Figure 2:

Version 2.1:

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Figure 2: Version 2: where the angle between the landing legs and top plate is increased from 110 degrees to 125 degrees

Intended Result:

• This results in a larger bottom footprint and lower height and center of gravity.

• The mass increase is is only only about 0.5 g.

• Retains existing top plate interface.

Unintended Result:

• To accommodate the new landing leg angle, the extensions of the bottom plate needed to be extended by about 16mm on each side.

  • Could be a strength concern → to mitigate this issue, we could introduce more material around it for reinforcement.

Author: @Smile Khatri updating Date: 2024/03/08

Design review 1:

• Looks good, thank you for organizing the data in a table

• We can cut off some more material from the bottom of the leg to lower the center of gravity even more

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Remove material below the red line

• Concerns related to the bottom plate make sense. We can potentially add more material to the edges but I doubt it will make a significant improvement in strength so I think this looks good for now. The plate will generally be in tension so I think it should be fine.

Open

Author: @Agapa Goombs updating Date: 2024/03/08

Version 2.2:

As seen in Figure 3, 8 mm was removed from the bottom of the landing legs:

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Figure 3: Landing Legs of Version 2.2 of Houston Landing Gear

The updated design of Version 2.2 is shown in figure 4:

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Figure 4: Design Version 2.2 of Houston Landing Gear with legs shorted by 8 mm.

The changes to the landing gear from Version 1 to Version 2.2 are summarized in the following table: