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8. PID Motor Position Control and Path Planning

In chapter 7, we achieved the velocity control design requirement R3, described in section 1.9. In this chapter, we achieve R4, the position control requirement:

  1. A technical user's commanded angular position trajectory of the mechanical load is achieved quickly and accurately and they can obtain the position measurements.

We have already developed most of the tools necessary to meet this requirement:

  1. User interface drivers (chapters 1 to 3)
  2. Motor driving and angular position measurement (chapter 4)
  3. Interrupt handling (chapter 5)
  4. Digital dynamic system realization (chapter 6)
  5. Digital controller realization (chapter 7)

Some additional tools will be developed in this chapter. Derivative compensation and proportional-integral-derivative (PID) control are introduced in sections 8.1 and 8.2, and their application to motors generally and the target motor in particular are looked at in sections 8.3 to 8.5. This includes designing a digital controller in MATLAB and deploying it directly to the target system. In section 8.6, a simple path planning algorithm is introduced that shapes the input command to the feedback system to move the load position smoothly from its starting point to its commanded destination.

Chapter contents

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