Smart Motor - V5 System Architecture

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.

Smart Motor

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.

Graph

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.

Internal circuit board

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.

Motor Programming
Settings
Motor.setVelocity()
Motor.setTorqueLimit()
Motor.setStopping()
Motor.setRotation()
Motor.setTimeout()
Actions
Motor.spin()
Motor.rotateTo()
Motor.rotateFor()
Motor.stop()

Advanced Options Motor.startRotateTo()
Motor.startRotateFor()
Sensing
Motor.isDone()
Motor.direction()
Motor.rotation()
Motor.velocity()
Motor.current()
Motor.power()
Motor.torque()
Motor.efficiency()
Motor.temperature()
  V5 Smart Motor Specifications Motor 393 + Controller 29
Speed Approximately 100, 200 or 600 rpm 120, 160 or 240 rpm
Peak Power 11 W 3.93 W
Continuous Power 11 W 2.70 W
Stall Torque (with 100 RPM cartridge) 2.1 Nm 1.67 Nm
Low Battery Performance 100% Power Output 51% Power output
Feedback Position
Velocity (calculated)
Current
Voltage
Power
Torque (calculated)
Efficiency (calculated)
Temperature
Position1
Encoder 1800 ticks/rev with 36:1 gears
900 ticks/rev with 18:1 gears
300 ticks/rev with 6:1 gears
627 ticks/rev with High Torque gears1
392 ticks/rev with High Speed gears1
261 ticks/rev with Turbo gears1
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
1.97” W x 2.16” L x 0.98” H
50 mm W x 55 mm L x 25 mm H
Weight 0.342 lbs
155 grams
0.209 lbs
95 grams

1. Motor 393 Position requires the Integrated Motor Encoder (IME).