Motors!
One of the first decisions we faced was what motors to use. This was a cross subsystem decision as the choice would impact many elements of the design. The motors we considered fell into two categories, steppers and servos. Steppers has the advantage of being easy to control to a precise location, but they are not super powerful and if they slip we have no way of knowing. Servo motors are much stronger and have a better torque curve, but tend to be more expensive and require an encoder or similar mechanism to measure position. We also needed controllers for the motors as well as power.
After looking in depth into the control of these various motor types, as well as calculating the torque and velocity required, we chose to go with an integrated servo system which can be found here. These have many features that are well suited for our needs.
- They are compact, while still having a very high power output
- Built in encoders solves positioning problem
- They are capable of smooth, high speed moves with a high level of precision
- They have integrated control boards which handle the complex motor control we deemed to be outside the scope of this class
- Simple interface mechanism
Because they are quite pricey we reduced the number of nodes on our MVP from four to three. This cuts the size space we can cover in half, but it does not negatively impact our capabilities otherwise nor does it restrict our ability to scale up to four nodes if we so desired.
These motors are well suited to our project, and we are very excited about the potential they bring to the table for precision and smoothness in control. We hope to learn a lot in the coming weeks about how to interface with them most efficiently, and are optimistic this will allow us to focus on the core challenges of our project without being help back my limitations in hardware and control.
