Paint delivery

We decided to purchase a dp X3 airless paint pump. As the spraying mechanism is partially manual (i.e. you have to pull a trigger to release the paint), we will be using a servo motor system, in order for the robot to pull the trigger without human intervention.

Vertical Movement Mechanism:

wHAT IT WAS

We decided to use aluminium profiles (Fig 2) to construct our vertical system, as well as the rest of the chassis. We would make the robot manually “extendable” (i.e. have differing lengths and configurations), by joining the aluminium profiles using joint connectors. As for the linear movement of the spray, we initially wanted to use a system similar to an OX CNC machine, as seen in Fig 3. When the motor turns, the driver pulley (the pulley connected to the motor shaft) will rotate as well, allowing the motor with the gantry plate to climb up the timing belt, similar to a gear rack and pinion system.  We wanted to use this as it seemed to be more suited for the extendable aluminium profile that we discussed earlier.

WHY WE CHANGED IT

We preserved the idea of using aluminium profiles and joint connectors, however we decided not to use the OX CNC system as it required the motor to be mounted on the gantry plates, which meant that the motors would be a moving part and hence add to the weight of the moving parts. In our final design, our motors are stationery and mounted at the end bottom of the robot.

Moveable Base

What it was

We decided to switch back to DC motors instead of Stepper motors as we realized that the robot base will now only be moving from right to left, and precision would not be as pertinent now. The DC motors fulfilled the requirements that we needed and were also much more affordable than the initial motors that we were considering. The new motors that we decided to utilise are typically used for children electrical vehicles. Since it is able to withstand the weight of a child, it should too be able to effectively carry the mass of our miscellaneous parts.

We will be purchasing four DC motors of model number 550, four wheels of 22cm diameter and two 30A double DC motor drivers.

Our base would be a 80x50cm base, where an aluminium sheet will be placed on top of a rectangle constructed aluminium profiles

why we changed it:

We preserved all other parts of this design, however we decided to create a double layered base to add more weight onto the base (to lower and centralise the CG), as well as allow for the paint can/paint pumps and wires/arduino boards/ drivers to be kept in separate compartments for the purpose of neatness.