How an application communicates with a USB device depends on the device driver that the OS has assigned to the device. The choice of driver in turn depends on finding a match between the information in the descriptors that the OS retrieves on device attachment or bootup and the information stored in the PC's INF files (assuming Windows).
Thus to access the robot, you will need documentation for the robot's driver. This might help:
Model 5174 – Robotics System Software Development Kit
http://www.labvolt.com/downloads/datasheet/dsa5150.pdfI'm not familiar with the capabilities of matlab programming, but if you can call API functions you should be able to access the robot.
A matlab forum might have some ideas.
Jan