Abstract
In this paper, we propose the application of DSP (Digital Signal Processor) to real time computation of dynamic control for robot manipulators in low cost. There are some applications of DSP to robot control so far, but these applications are not to main computational part in robot control such as kinematics or dynamics.
Generally, many of DSP can not operate in floating point, but in fixed point. Therefore, it is usual to scale each physical value of each unit in order to obtain accurate fixed point expression. However, this scaling method is not sufficient in the case of the precise computation for robot manipulators, because the absolute physical values at each link may change in very wide range through every link while a manipulator is moving. Therefore, there is a possibility that computation result includes large error. In this paper, we propose a new scaling method regarding the structure of recursive computation for robot manipulators in order to avoid large computational error.
Then, we constructed actual control system by using a 16 bit micro computer as a host computer and TMS 32010 as a DSP. Lastly, we confirmed that DSP can compute the unified computation of kinematics and dymamics for general 6 d. o. f. manipulators in 3.74 msec though 16 bit micro computer requires 68.9 msec for the same computation. It is also shown that the total computation of dynamic control including trajectory calculation and feed back calculation for general 6 d. o. f. manipulators can be performed in 14.71 msec by using this DSP/microcomputer system and it takes more than 80 msec for the same kind of computation when only a 16 bit microcomputer was used.
