Understanding IQ Smart Motor Performance

Diagram illustrating the motor components of the VEX IQ Robotics platform, highlighting key parts and their functions, designed to support educational resources for beginners in robotics.

The IQ Smart Motor had to be perfect for IQ 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.

Maximum power is 1.4W continuous and maximum torque is 0.414 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 Smart Motor uses a Texas Instruments MSP430 microcontroller running at 16 MHz to process requests, measure speed and direction, monitor current, and control the motor via an H-Bridge. The H-Bridge, also from Texas Instruments, has automatic overcurrent and over temperature protection. Speed and direction are measured via a built-in quadrature encoder that uses a wheel with tiny slots and light sensors. PID loops are processed internally to precisely control output speed and rotation. Current is also measured, to ensure motors don't get too hot during use. All this technology works together to make a Smart Motor that is simple, flexible, and powerful.

“Consistent motor performance is a game changer”

One of the IQ 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.

The motor calculates accurate output velocity and torque, giving the user a true understanding of the motor's performance at any time. Position and angle are reported with an accuracy of 0.375 degrees. All of this data is reported on the motor’s dashboard (1st gen or 2nd gen).

Motor Programming in C++ with VEXcode IQ
Settings
Motor.setPosition(0, degrees);
Motor.setVelocity(50, percent);
Motor.setStopping(brake);
Motor.setMaxTorque(50, percent);
Motor.setTimeout(1, seconds);

Actions
Motor.spin(forward);
Motor.stop();

Sensing
Motor.isDone()
Motor.isSpinning()
Motor.position(degrees)
Motor.velocity(percent)
Motor.current(percent)

For more information about programming in C++, Python, or Blocks with VEX IQ Smart Motors, view this section of the VEX Library.

Motor Name IQ Smart Motor
Part Number 228-2560
Peak Power 1.4W
Speed (RPM) 120 RPM
Stall Torque (Nm) 0.414
Feedback Position
Velocity
Current
Encoder

960 ticks/rev

Dimensions 2.24" W x 2" L x 1" H
(56.9mm W x 50.8mm L x 25.4mm H)
Weight 0.165 lbs
(75 grams)

For more information, help, and tips, check out the many resources at VEX Professional Development Plus

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