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Playing robots use CAN-based motor controllers

The FIRST Robotics Competition (FRC) is for high-school students. They build playing robots. Some of the students develop motion control applications using the Jaguar motion control kit by Texas Instruments. TI is one of the FRC sponsors. The kit has been designed specifically for this students’ competition. It is based on the Stellaris processor family. This ARM processors provide a CAN interface on-chip.

OF COURSE, MANY OF THE MOTORS USED in the robots are simply turned on or off. But for any sort of control of the motors or the mechanical motion they enact, perform, or enable, a Jaguar motor control module is needed. It provides sophisticated motor control for smooth starts, increasing ramps, rock-steady motion, accurate speed, and controlled braking of 12- and 24-volt DC brushed electric motors. This module was designed, not for children to build toy robots, but for engineers needing to precisely control powerful industrial motors in coordination with complex integrated systems of motors that are part of an automated factory floor, process control, product distribution, machine tool, or medical instrument.
While sophisticated and precise control is possible, programming the Jaguar, like all Stellaris motor controllers, is simple and straightforward. With exotic motor control algorithms already part of a library of programs, the designer can select the appropriate algorithms, enter a few parameters that describe the desired motor movements, and have the motor that comes in the kit operating properly in as little as five minutes.
TI’s control module with CAN (MDL-BDC24) includes a set of sensor interfaces, connectivity, and control options, including analog and quadrature encoder interfaces. The module uses the 32-bit Stellaris micro-controller that implements open-loop voltage control as well as closed-loop control of speed, position, or motor current.
In the 2010 competition, teams used already the TI modules. They updated firmware, configured the controllers, and read the controller status over CAN. In addition, for FIRST operation, the Jaguar provides trusted CAN communication, which was used to power down a malfunctioning robot or power down all robots. This ensured that it is safe to enter the playing field. The motor controller also incorporates several high-quality analog components from TI, including the SN65HVD1050 CAN transceiver, the MAX3221 EIA-232 line driver/receiver, the TPS54040 swift DC/DC converter, the TPS73633 voltage regulator, and the INA193 current shunt monitor.

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Texas Instrument


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