Chapter 13 develops a design for an adaptable mobile robot using an FPGA board as the controller. Servo motors and several sensor technologies for a low cost mobile robot are described. A sample servo driver design is presented. Commercially available parts to construct the robot described can be obtained for as little as $60. Several robots can be built for use in the laboratory. Students with their own FPGA board may choose to build their own robot following the detailed instructions found in section 13.6.
The FPGA-bot shown in Figure 13.1 is a low-cost moving robotics platform designed for use the DE1, DE2, UP3, or UP2 board. The FPGA-bot is designed to be a small autonomous vehicle that is programmed to move in response to sensory input. A wide variety of sensors can be easily attached to the FPGAbot. The round platform is cut from plastic and a readily available 7.2V or 8.4V R/C rechargeable battery pack is used to supply power. Two diametrically opposed drive motors move the robot. A third inactive castor wheel or skid is used to provide stability. The robot can move forward, reverse, and rotate in place. Two relatively inexpensive radio control servos are used as drive motors. The FPGA is programmed to act as the controller. The R/C servos are modified to act as drive motors. The servos are controlled by timing pulses produced by the FPGA board.
KeywordsDuty Cycle Rapid Prototype Dead Zone Drive Motor Output Shaft
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