A dolly with assisted stair climbing

My bachelor thesis was to design and build a dolly that could carry a heavy, sensitive payload up and down stair with minimal force necessary from the user. The solution I and my group came up with was to build a motorized dolly.

Figure 1: The payload is the black package. The system was built on top of an off-the-shelf dolly.

Figure 1: The payload is the black package. The system was built on top of an off-the-shelf dolly.

The working principle was that a flipper would push against the stairs to either pull the dolly up or resist it going down. The control was very simple, the user commanded forward, off, or backward.

Figure 2: The drivetrain was a motor that turned a perpendicular shaft. The universal joint and bearings were to take radial loads off of the motor shaft.

Figure 2: The drivetrain was a motor that turned a perpendicular shaft. The universal joint and bearings were to take radial loads off of the motor shaft.

Figure 3: The controller was just two buttons. The underlying computation was done by a few logic gates.

Figure 3: The controller was just two buttons. The underlying computation was done by a few logic gates.

The most fun part of this project was that I got to machine most of the parts my self on a manual mill and lathe.

Figure 4: One of the drawings for a part that I made. You can see it in figure 2 holding each of the wheels on.

Figure 4: One of the drawings for a part that I made. You can see it in figure 2 holding each of the wheels on.

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