V5 Motor Overview

Function

The V5 Smart Motor is the product of thousands of hours of engineering and analysis aimed at perfecting the gears, encoders, modular gear cartridges, as well as the circuit board, thermal management, packaging, and mounting. This thoughtful design allows users to control the motor's direction, speed, acceleration, position, and torque that turn the robot's wheels, arms, claws, or any movable component. The V5 Smart Motor provides feedback data about its position, velocity, current, voltage, power, torque, efficiency, and temperature. 

Features & advancements

Integrated Control System

• The V5 Smart Motor's internal circuit board uses 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 (proportional–integral–derivative) with control over the velocity, position, torque, feedforward gain, and motion planning similar to industrial robots. The PID is internally calculated at a 10-millisecond rate and the PID values are pre-tuned by VEX for consistent performance across all operating conditions. 
• Users can adjust the motor's PID values to tune a motor's performance for more advanced mechanical systems. Advanced users can bypass the internal PID and take direct control with raw, unaltered PWM (pulse-width modulation) control. PWM, like PID control, still has the same limits that keep the motor's performance consistent.
• Additional control of the V5 Smart motor is achieved by internal encoders. These measure the amount of rotation of the shaft socket. The rotation is divided into a number of steps or “ticks” which provides feedback as to the amount a shaft has turned. The resolution of the encoder is determined by the internal gear cartridge of the motor.

• The V5 Smart Motor is completely consistent in its performance. The motor runs internally at a slightly lower voltage than the V5 Robot Battery's minimum voltage, and the motor's power is accurately controlled to +/-1%. This means the motor will perform the same every time, regardless of the battery's charge or the motor's temperature.
• The motor's internal temperature is monitored to make sure the motor lasts. If the motor starts to overheat, there is a warning. If the motor reaches its temperature limit, performance is automatically reduced to ensure no damage occurs. The motor has four levels of response to rising temperatures. Each temperature level limits the motor current: level 1 = 50% current, 2 = 25% current, 3 = 12.5% current, 4 = 0% current.

Feedback Data in Motor Dashboard

• The motor calculates accurate output power, efficiency, and torque. It also reports its position and angle with an accuracy of 0.02 degrees. Those calculations and other data are reported and graphed on the V5 Robot Brain's motor dashboard, as shown above.

Note: Be sure the gear ratio displayed in the Gears frame of the motor window matches the V5 Smart Motor Cartridge the motor is paired with. The gear ratio display can be changed by touching the Gears frame on the touch screen.

• The V5 Smart Motor ports are illuminated with a red LED for visual communication.

• The motor’s #8-32 Threaded Inserts can be flipped over in the motor’s housing and this will make them flush with the housing rather than slightly protruding. This is useful when the motor will not be mounted directly to a piece of structural metal. For example, this will allow the motor to be mounted using standoffs.
• There are replacement parts for the motor. These include the V5 Smart Motor Cap Replacement and the V5 Smart Motor #8-32 Threaded Inserts. Parts which can be used to repair a motor so an entire motor does not need to be replaced when it's damaged. 
• The motor's shaft socket can accommodate a High Strength Square Gear Insert.

How it improves the user experience

• Aside from the control and consistency that the V5 Smart Motor supplies, the motor has easy-to-replace internal gear cartridges for output gear ratios of 36:1 (100 rpm) for high torque & low speed, 18:1 (200 rpm) for standard gear ratio for drive train applications, and 6:1 (600 rpm) for low torque & high speed which is best used for intake rollers, flywheels, or other fast moving mechanisms. This makes the V5 Smart Motors faster than the previous 393 Motors. For more information, please refer to: How to Change a V5 Smart Motor Gear Cartridge.
• Whereas the 393 Motor maintained only 2.7 watts of continuous power and peaked at 3.93 watts, the consistent 11-watt power levels during both peak and continuous performance enhance the stability of the V5 Smart Motor. 
• While the battery is low, the V5 Smart Motor continues to put out 100% power, unlike the 393 Motor which reduced to only 51% power under low battery conditions. This greatly improves the V5 Smart Motor's consistency, especially in combination with other previously explained enhancements.
• As previously explained, the V5 Smart Motor provides feedback data related to position, velocity, current, torque, temperature, etc. This is a great improvement over the 393 Motor that only provided feedback related to its position. The V5 Smart Motor's feedback system provides a user with the information needed to then iterate on their robot and program. These are valuable learning opportunities for new robotics students who can then account for these factors within their designs, and for more experienced robotics students who can visually see the relationships and dynamics within the motor's functioning.