A good guide: https://wiki.purduesigbots.com/hardware/vex-drivetrains

VEX's guide: https://kb.vex.com/hc/en-us/articles/360035952771-Drivetrain-Drivetrains-for-VEX-V5

VEX's other guide: https://curriculum.vexrobotics.com/curriculum/drivetrain-design.html

Understanding V5 Smart Motor Performance: https://kb.vex.com/hc/en-us/articles/360044325872-Understanding-V5-Smart-Motor-Performance

Drivetrain comparison information:

CAD videos are on the Fusion360 page

How to make V5 Smart Cables: https://youtu.be/GpDXPrXWQqQ

The V5 Smart Motor had to be perfect for V5 to be successful. Thousands of hours of engineering and analysis went into designing this motor. Everything has to work together: the motor, gears, encoder, modular gear cartridge, circuit board, thermal management, packaging and mounting. Users can control the motor’s direction, speed, acceleration, position, and torque limit.

This graph says it all. Maximum power is 11W continuous and maximum torque is 2.1 Nm. Free speed is software-limited by the motor’s processor to keep consistent performance motor-to-motor and to allow top speed under loads.

The V5 Smart Motor’s internal gear design has to withstand all the motor’s power, and the abuses of external forces coming into the motor from loaded arms and robot momentum. The gear train is our most robust yet. Metal gears are used in all high torque locations for strength. Plastic gears are used in the low load, high speed locations for smooth and efficient operation. An internal gear cartridge is user changeable for output gear ratios of 6:1, 18:1, and 36:1.

The motor’s internal circuit board has a full H-Bridge and its own Cortex M0 microcontroller to measure position, speed, direction, voltage, current and temperature. The microcontroller runs its own PID with velocity control, position control, torque control, feedforward gain, and motion planning similar to industrial robots. PID is internally calculated at a 10 millisecond rate. The motor’s PID values are pre-tuned by VEX for excellent performance across all operating conditions. Users can adjust these values to tune the motor’s performance for their specific application.

Advanced users can bypass the internal PID and take direct control with raw, unaltered PWM control. Raw control still has the same rpm limits, current limits, and voltage maximum that keep the motor’ s performance identical.

“Consistent motor performance is a game changer”

One of the V5 Smart Motor’s most unique capabilities is completely consistent performance. The motor runs internally at a slightly lower voltage than the battery’s minimum voltage, and the motor’s power is accurately controlled to +/-1%. This means the motor will perform the same for every match and every autonomous run, regardless of battery charge or motor temperature.

Stall current is limited to 2.5A to keep heat under control without affecting peak power output. Limiting stall current eliminates the need for automatic resetting fuses (PTC devices) in the motor, which can cause unintended motor outages. The 2.5A limit essentially removes the undesirable region of the motor’s performance curve, ensuring users do not unintentionally create stall situations. Finally, to make sure the motor lasts, the internal temperature is monitored. If a motor is approaching an unsafe temperature, the user gets a warning. If the motor reaches its temperature limit, performance is automatically reduced to ensure no damage occurs.

The motor calculates accurate output power, efficiency, and torque, giving the user a true understanding of the motors performance at any time. Position and angle are reported with an accuracy of .02 degrees. All of this data is reported and graphed on the motor’s dashboard.