Acceleration of parallel robot kinematic calculations in FPGA

An application of field programmable gate arrays (FPGA) to accelerate calculations of the inverse kinematics problem solution for a parallel robot is presented in the paper. The robot is designed for milling by moving a milling cutter along a desired trajectory generated in the Cartesian space. For a position controller of the robot, each point of the trajectory must be transformed into the joint space by the solution of the inverse kinematics problem, thus must be calculated on-line at high frequency. The paper shows how to decrease the calculation time, preserving required accuracy, by augmenting the arithmetic-logic unit (ALU) of a microprocessor with custom instructions. The hardware implementation of the accelerator is described and results of calculations performed in an Altera FPGA chip are analyzed.