Drive System
When designing the drive system for the radio shuttle, once again it was more than likely a motor and pulley system would in some way be incorporated into the design due to the availability of both. However during concept generation, some other options were evaluated which could be considered more advanced. The following concept ideas were discussed:
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2 wheel drive
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4 wheel drive
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tank treads
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motorised shelf rails
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Maglev technology
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After careful consideration the 2 wheel drive concept was selected to be designed further because of the efficiency regarding space and components required. This design was also much more simple to implement than some other concepts.
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The motor to be used as part of the driving system included a speed gear reducer which was extremely useful for the driving system. It was important for the shaft to cease rotating as soon as the power to the motor was cut otherwise the prototype would be out of position along the shaft.
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Shafts of 10mm diameter were sourced in the university to be used for the drive shaft and the other wheel shaft. Simple wheels with a bore diameter matching that of the shaft were purchased to include as the main wheels of the prototype which would allow the movement across the shelves.
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A belt of 300mm in length was available for use but unfortunately there was no accompanying set of pulley drums. Therefore, two pulley drums were to be modelled on Solidworks which were compatible with the teeth of the belt and then 3D printed. The power available from the motor indicated that the size ratio between the pulley drums could be equal to one.
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When designing the drum, the diameter was made so that no interference within the assembly would be caused by the component but the belt would still fit securely given the lateral distance between the two drums.
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The pulley drum which was to rest on the drive motor shaft had a key section cut from the centre where an extrusion on the motor shaft itself would fit in and secure the two parts together. Concerning the pulley drum on the drive shaft, additional material was designed to extrude from one of the faces and a hole was included where a bolt would be placed through and tightened by a nut. This was to secure the pulley drum to the shaft and ensure simultaneous rotation between the two. It should be noted that a screw could not be used as a thread was too intricate for the 3D printer to produce.
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The above was all modelled on Solidworks with minimal issues.
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Calculations derived from the performance of the drive motor such as the velocity of the shuttle and the required power from the motor are available in the final report.
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