Case Studies

Car motor

Motor Endurance Test

Posted in Embedded Development & Programming, LabVIEW, Manufacturing Automation and Intelligence, Motion Control, Product Development, Test & Measurement Automation, Test and Measurement

Summary

DMC programmed a multi-station motor endurance test system. The system utilized National Instruments hardware and software to control motors, monitor performance, and collect data throughout 500 hour endurance tests. Magtrol dynamometers apply a load to each motor and a PID control loop maintains the appropriate motor current, as specified by the test sequence. An autotuning algorithm allows the user to easily configure the system for any size motor and brake.

Solution

DMC implemented a real-time program to asynchronously control up to three motors and brakes. The real-time program runs on an NI cRIO and utilizes the cRIO’s hybrid mode, which runs custom FPGA code in tandem with NI’s standard “Scan Engine” for interfacing with several data acquisition modules. The custom FPGA code is used to calculate RMS current and voltage at 50 or 60Hz, depending on the type of AC power that is used for the motor. A Windows-based LabVIEW application runs on a touchscreen and communicates with three cRIOs to enable the operator to configure a test sequence, manually control the motors and brakes, start and stop test sequences, initiate autotuning, view past data, and investigate faults. The Windows application allows for future expansion to up to six cRIOs, for a total of eighteen motors running on one system.

The motor test sequence is designed to simulate real-world motor usage, with varying levels of current being controlled by a PID feedback loop. The program monitors the motor current and temperature and automatically stops the test if the motor stopped performing adequately.

DMC modified NI’s PID toolkit to increase the robustness of the autotuning algorithm and allow multiple motors to be autotuned simultaneously on a single cRIO. The autotuning algorithm saves a lot of time and requires less operator training to configure a new tool because manually tuning a PID control loop for a system with unknown response can be a long and complicated process.

Customer Benefits

  • Ensures quality of production motors and test robustness of prototype motors in development
  • Reduces test configuration time and effort by implementing an autotuning algorithm that requires minimal operator knowledge or input in order to set up a new tool
  • Remote monitoring application allows the operator to monitor the tests from outside the test lab

Technologies

  • National Instruments cRIO, FPGA, data acquisition and output modules
  • National Instruments PID and Fuzzy Logic Toolkit
  • Windows-based touchscreen interface, running a LabVIEW application
  • Magtrol dynamometers