Initial Concept
The Autocart was first conceived as a small remote controlled electric cart for transporting basic materials around a construction site. The design was refined through many testing phases and ended with the design shown.
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Treads instead of wheels for rough terrain where traction is key
Flat top for maximum storage space with inserts for additional storage options
Direct control rather than remote controlling due to safety concerns
Intended payload up to 800 lbs.
The cart had to move as fast as a normal walking pace
The dimensions had to be such that the cart could fit through standard size gates
Research
Research for the design included finding codes and regulations for electric motorized construction equipment. Looking up similar devices and other reference material.
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The most important regulations came from OSHA guidelines regarding electric power tools and the proper way to protect users from touching potentially dangerous components. (1926.300)
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Research found several warehouse vehicles with flat tops for moving inventory. the main difference is that the Autocrat is designed for uneven terrain at construction sites. The Autocart is designed based on basic golf carts in both size and weight requirements.
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The most similar product is the STEED military cart which resembles a typical wheelbarrow that has been motorized. the difference is the Autocart doesn't require the user to lift one end of the cart to move it.
Autocart Parts
Motor
Based upon payload requirements and similar existing vehicles the motors were chosen to be Motoenergy ME0708 capable of constant 6.4 HP and 3500 rpm
Motor speed controller
The speed controller is used to control the motors RPM based on the user input. The LANTRO JS-10-50V motor speed controller is capable of controlling the motor from 0-100% of its range
Battery
The Autocart design uses a reasonable sized battery than can be swapped out when it dies for minimum downtime on the job site. Lithium ion batteries provide a middle ground between battery life and price
Track System
The track system design is based on a tank track system with suspension. this design allows for the cart to be higher off the ground which increases ground clearance and adds more room to fit the components. The design uses a rubber track that is designed for non-smooth ground travel
Chassis
The chassis is designed as a mix of steel and aluminum alloy. The steel is used in the frame from maximum rigidity and structural stability. The aluminum alloy is used for the bed shell which protects the internal components
Physical Controls
The Autocart is designed to be controlled with a simple controller directly connected to the cart. The controller design consists of 2 scroll wheels that correspond to each motor. Pushing forward will cause the motor to spin forward and pulling back will cause the motor to spin in reverse. There will also be an emergency stop button that will immediately shut down the motors