Application of DSP to real-time computation for dynamic control of robot manipulators

Abstract

In this paper, the application of a DSP (digital signal processor) to real time computation for low-cost dynamic control of robot manipulators is proposed. In order to realize dynamic control in real time, a DSP is utilized for the main part of the computations for robot manipulators such as kinematics and dynamics. Many DSPs do not do floating point arithmetic but rather fixed point. Therefore, it is usual to scale the physical values of each unit in order to obtain accurate fixed-point expressions. However, conventional scaling methods are not sufficient in the case of robot manipulators, because the absolute physical values at each link might change over a very wide range while the manipulator is moving. In this paper, a new scaling method which considers the structure of recursive computation for robot manipulators is proposed in order to avoid large arithmetic errors. A control system was constructed using a 16-bit microcomputer as the host computer and TMS32010 as the DSP. It was confirmed that the DSP can execute the unified computation of kinematics and dynamics of general 6-DOF (degrees of freedom) manipulators in 3.74 ms while the 16-bit microcomputer requires 68.9 ms for the same computation.