The V5 Smart Motor (5.5W) had to be perfect for EXP to be successful. Thousands of hours of engineering and analysis went into designing this motor. Everything has to work together: the motor, gears, encoder, 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 5.5W continuous and maximum torque is 0.5 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 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.
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 5.5W 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.
|Motor Name||V5 Smart Motor (11W)||V5 Smart Motor (5.5W)|
|Gear Cartridge Ratios||35:1
|Speed (RPM)||100 with 36:1 Cartridge
200 with 18:1 Cartridge
600 with 6:1 Cartridge
|Stall Torque (Nm)||2.1 with 36:1 Cartridge||0.5|
|Encoder||1800 ticks/rev with 36:1 gears
900 ticks/rev with 18:1 gears
300 ticks/rev with 6:1 gears
|Dimensions||2.26” W x 2.82” L x 1.30” H
(57.3 mm W x 71.6 mm L x 33.0 mm H)
|2.25" W x 2.5" L x 1" H
(56.8mm W x 63.4mm L x 25.1mm H)