SOLIDWORKS for Makers: Design and Create a Remote Control Car Part 1

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While attending 3DEXPERIENCE World in Dallas I had the pleasure of being involved with the Makers Zone within the playground. I worked with some great Makers to design a simple and easy remote control car which attendees could have a go at making. I enjoyed the activity and the designing of this so much I decided I wanted to recreate it on my return to the UK. As usual work life and home life decided to both get busy at once and it took a few months before I could circle back round to this idea.

The design we used for 3DEXPERIENCE World was simple and effective, it used 4 continuous rotation servo motors to propel itself along and for steering. Rather than using the traditional rack and pinion car steering method, the design used a gyroscopic mixed mode controller to enable the car to spin on the spot. This is known as skid steer and is commonly seen on bulldozers or tanks. These servos were powered by a small battery and controlled using a cheap RC Trigger controller with a gyroscopic type of receiver. Other than these main components I’d need some Y servo cables to allow me to power two servos in parallel and some other wiring accessories.

From here once I’d gathered the electronic components and tested that the setup was working as expected I needed to sit down at my desk and get into some design work. The first components I’d need to design was a mount for the servo’s to connect to the chassis I was yet to design. I chose to start with this as I’d need the designed hole centers on the motor mounts to match on the chassis.

The Servos had a width of 40.8mm and a height of 20mm, I’d start by creating a cutout in this size for the servo to sit within, I added 0.5mm to each dimension to allow for tolerancing. I offset this sketched rectangle by 10mm to create the frame in which the servo would bolt to. I started a new sketch and drew out a rectangle on the lower surface of the window frame I’d made previously. I extruded this 5mm before starting work on how the servo would be held in place. The servo’s have small tabs on both sides to allow these to be clamped against the mount, I added some thru holes to this into which I would use some heat set inserts to create a proper thread into which the fixing could be secured. I used the same process on the flat lower surface which would allow the created mount to be fixed to the chassis plate. I removed some excess material on the frames upper edge using the cut extrude feature and finished off by adding some fillets to round off the design. Once finalized it was easy to make these parts as I opted to use FDM 3D Printing to manufacture the design.

For the chassis plate I would be using laser cutting as my method of manufacture, since I bought my laser cutter 3D printing large flat shapes is a thing of the past. It’s so much easier to watch a laser quickly cutout a flat profile from a created DXF file than it was to wait 10 hours plus to print one!

The design for this was easy, I started by creating a new sketch before drawing two construction lines which would act as my mirror references. The baseplate would be rectangular in shape and would need to be wide enough to allow two servo motors to be mounted side by side. I sketched a rectangle from origin 200mm in length and 90mm in width. The hole centers for the motor mounts needed to be replicated in the same positions on the chassis. To do this I created a rectangle within one of the quadrants created earlier and used the smart dimension tool to set this at the correct hole centers. I then added some more smart dimensions to lock this into the correct position. The next piece of the chassis plate puzzle was to use the mirror command to create the remaining hole patterns for the rest of the mounts. Once the sketch was finalized, I used the extrude bodies command to create a 3mm thick plate. I then created a new sketch to create a grid of holes down the center portion which I could use to secure other components into place if required. I used the extrude cut command to turn this sketch into thru holes in the plate. I saved this as a DXF file to load into my laser cutter.

The servo motors which I had bought came with a selection of different hub designs for different applications, I’d be using one of the round variants with a number of mounting holes. To make my vehicle move I needed to design some wheels, I had a few options here… large or small diameter, wide or thin profile or did they even need to be round at all! The electronic system I had created would operate on skid steer, so I really wanted to build a track-based system rather than having 2 separate wheels. I’d use elastic bands to connect the front and rear wheels together to achieve the full tracked look.

As I was unsure what diameter would perform best, I decided I’d create two designs and see which worked best once I had made them. I started by creating a circle to match the diameter of the hub I’d be using, I then had to create an array of holes to match that of the fixing holes on the hub. I did so by measuring the provided hubs using a vernier caliper, I found that they we’re set on a 15mm square profile.

The first thing I would need to do was to mirror this on the wheel design to enable it to bolt into place. I created a square with Center at origin equal in both width and height at 15mm, on each corner I sketched a 2mm diameter circle to allow the bolts to pass through and connect to the hub behind. From here I sketched a 20mm diameter circle to match that of the outer diameter of the hub, once this was in place it was time to start the actual wheel design. I started by sketching an upright line before offsetting this in both directions by 1.5mm to create a singular wheel spoke. Power trim quickly removed all the crossing lines and parts which I didn’t need, I always find it best to tidy up extra lines before patterning as otherwise you just end up removing 10x as many… I again used a circular pattern to create the 10-wheel spokes. With the sketch completed I extruded this 25mm to create the body.

As I didn’t want to have a thick, dense looking wheel I use a quick sketch and extrude cut command to cut into the wheel face to reduce the weight and print time. I didn’t want the elastic bands which would connect the front and back wheels to be able to slip over the edge of the wheel, so I used a couple of new sketches to add a 0.5mm lip on the inner and outer edges. To create the larger wheel, I used the scale command to increase the model size in only the X and Y axis, the Z axis staying the same to retain the 25mm wheel width. As with the motor mount my method of choice to produce these would be 3D printing, I saved the two designs as STL files before preparing these to print in the slicing software.

With the designing complete it was time to get started with the making, check out part 2 to see how my created designs went from the screen to reality. Watch how I used 3DEXPERIENCE SOLIDWORKS for Makers to complete this design below:

Jonathan Harrison

Jonathan Harrison

By Day I lead a Design and Product Engineering team and by night I make cool ideas come to life. I'm self taught in SOLIDWORKS and have been using it for over 10 years in both a professional and hobbyist sense, I'm lucky enough to be a SOLIDWORKS User Group Leader and Champion. My favourite quote and life moto is "If you can dream it, you can do it" and failure only means we haven't found the correct solution yet!