View Single Post
  #11   Spotlight this post!  
Unread 06-05-2008, 08:43
Gdeaver Gdeaver is offline
Registered User
FRC #1640
Team Role: Mentor
 
Join Date: Mar 2004
Rookie Year: 2001
Location: West Chester, Pa.
Posts: 1,370
Gdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond repute
Re: Victor logistics.

If you want to build a motor driver and are going to use 12 volt or more then there are some single chip solutions that can offer more ability. The victor everybody is familiar with is an open loop design. It provides no feed back or protections. If you going to use a micro controller to command the H-bridge then with a little more work you can have Current feed back, thermal protection and over current protection. With current feed back and knowing the motors current function then you can have sensorless speed control with fair accuracy. For low current motors look at the Freescale MC33887. For more current ability the ST Micro Electronics VNH2SP30 chip offers many features.
Infineon also offers the BTS 7960 and BTS7930. These are half bridge chips.
Pololu.com offers the first 2 chips on carriers and would simplify working with them. They are surface mount and not for bread boarding. Robotpower.com offers the simple H with the BTS7960. The nice thing about the VNH2SP30 is that it only needs the fixed frequency - variable duty cycle PWM on 1 pin. The other chips need 2 PWM outputs from the microcontroler. The next step to this is to control the speed controller over a serial buss. Note that the Lego NXT offers I2c and RS485 for this purpose. May be First and IFI will add some intelligence to the next generation speed controllers.