An FPGA based motion control IC and its application to robotic manipulators

This paper presents an FPGA based motion control IC by integrating most of the motion control functions into one FPGA chip. The hardware system of the FPGA executes quickly in dedicated parallel hardware without timing overhead penalty of a serial processor. The update rates of the current control loop and position/velocity control loop can be up to 120 kHz and 40 kHz, respectively. The new designed motion control IC can be incorporated with a general-purpose microcontroller or DSP to provide a simple, compact, low-cost, and effective solution for high sampling rate motion control system. A fully digital 3-axis motion controller/amplifier is designed by using the proposed motion control IC. In order to increase the sampling frequency of the system when using dynamic control algorithm for robotic control, the dynamic control algorithm can be partitioned into a linear portion and a nonlinear portion. The linear portion with position/velocity feedback represents the major control loop and is implemented in the FPGA based IC. The nonlinear portion acts as dynamic compensation to the linear portion to perform complex modeling related calculations, and is implemented in the DSP. Experimental results demonstrate that the new proposed system is successful and it exhibits much improved motion performance especially during high-speed motions.