Group Alpha's "Helman Motor Controller"

Thumbnail imageBigOpenQuote2 Because of the ease of use and robustness of Trace Systems’ TCPMaker, we were able to get the user interface up and running in 10% of the allocated time. We would definitely recommend it to anyone implementing a web appliance! BigCloseQuote2

 

Jerry Crane

Group Alpha, Inc.

 

 

 

Helman Motor Controller

 motor-controller-screen-shot

The Helman motor controller is a product which Group Alpha designed and builds for Helman Engineering of Greenville, SC. The controller is part of a closed loop system that controls a brushed DC motor to provide constant tension on fiber as it is wound. In particular, it is principally used for the fabrication of large carbon fiber based pressure vessel of the type used by NASA.

The controller is based on a Microchip PIC32 processor. This processor performs the basic signal conversion, loop control, and waveform generation to drive the motor. A simplified block diagram is shown below.

FiberTensioningSystem

 

The DC motor‘s spindle is used to mount the supply spool of fiber. The motor is a ¾ HP 130V DC motor. The fiber from the supply spool travels across an idler pulley attached to a load cell which measures the amount of tension in the fiber. The fiber then continues on to another idler direction changing pulley and on to the take up spool.

The DC motor is driven bi-directional by the motor controller to maintain constant tension in the fiber. The output of the controller is basically a 500W four quadrant PWM amplifier operating at 20 KHz. The controller uses a set of command signals (enable, command) to control the tension and it provides a set of status signals to provide remote monitoring of operating and fault status. Photographs of the PCB for the controller is shown below.

MotorControllerFront8

 

BigOpenQuote2The customer had a desire to operate and monitor the system remotely. From an operation standpoint we wanted a system that would allow the user to quickly tune the system for his particular application. For this reason we designed the system so that all of the necessary control parameters and operating parameters could be observed/controlled on a PC using a standard web browser. The web interface allows the user to monitor the system feedback, command, and error real time. The user can then adjust the proportional, derivative, and integral control of the system loop to obtain optimum performance over a wide range of fiber speeds and tensions.

 

The system software uses the Microchip TCP/IP stack to implement a web server that provides all of the user interface information to a PC connected via the Ethernet interface on the card. When the system was in the planning stage we planned on the web server function and user interface to take about the same time as the motor control software. Because of the ease of use and robustness of “Trace Systems’ TCPMaker”, we were able to get the user interface up and running in 10% of the allocated time. We would definitely recommend it to anyone implementing a web appliance!BigCloseQuote2

Jerry Crane

Group Alpha, Inc.