An Obstacle Avoidance Two-Wheeled Self-Balancing Robot

This paper introduces a Two -Wheeled SelfBalancing Robot (TWSBR) which is controlled to avoid obstacles. The TWSBR is a type of the inverted pendulum and is treated as an inherently unstable nonlinear system. Therefore, a continuous appropriate control is required to maintain the inverted state. The TWSBR consists of two DC motors with encoders and 6 -axis sensor (accelerometer and gyroscope). All peripherals are connected to a 32 -bit RISC -V soft microprocessor implemented on an FPGA, and all control circuits for the peripherals are also implemented on the same FPGA. An attitude control system of the TWSBR is provided through 3 Proportional -Integral- Differential (PID) controllers with a sensor fusion -based on a Kalman Filter, which is implemented on the 32 -bit RISC -V soft microprocessor. The obstacle avoidance system of the TWSBR is based on a fuzzy control using multiple ultrasonic sensors. The 32 -bit RISC -V soft microprocessor includes a 32 -bit fixed-point (Q16.16) arithmetic instructions of addition, subtraction, multiplication, maximum and minimum as a custom instruction set architecture (ISA) extensions for calculation of a speed improvement. The software program is written in C language and compiled by the GNU GCC cross -compiler for the RISC -V ISA.