Digital signal processor microchips applied to aerospace control systems

The author reviews the requirements placed on the controller in real-time aerospace control applications and compares them with those found in the digital signal processing (DSP) field. The application of a family of powerful DSP microchips to the field of aerospace control systems is studied. An example of a simple control system is used to present the basic concepts and to show the effects of data sampling rate. The code sequence required to implement the control law is shown for a floating-point DSP microchip, and the timing is also given. It is concluded that DSP microchips, such as the Motorola DSP56001 and DSP96002, are extremely powerful and have the speed necessary for real-time control applications. Their instruction sets easily meet the requirements for real-time operating systems. Fixed-point units, such as the DSP56001 with 24-b precision, are more than adequate for many applications. For complicated control systems, like those using Kalman filtering to predict the state of the system, DSP microchips with floating-point capability, such as the 32-b DSP96002, would be the logical choice, for they increase dynamic range and are much easier to use.<>