Position or velocity control system and method

Patent metadata

Field	Value
Publication number	US-11874644-B2
Application number	US-202117146083-A
Country	US
Kind code	B2
Filing date	Jan 11, 2021
Priority date	Dec 14, 2017
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

In described examples of methods and control systems to control a position and/or velocity of a machine, control circuitry is coupled to receive and dither a control signal, and to compute a control output value according to the dithered control signal and a control function. An inverter is coupled to the control circuitry, to control the position and/or velocity according to the control output value.

First claim

What is claimed is:

1. A circuit to control a position and velocity of a machine, the circuit comprising:
an electronic memory; and
a processor configured to execute program instructions stored in the electronic memory to:
control the position according to a reference position pulse signal;
compute a parameter according to a velocity error value and a control function;
compute a control output value as a sum of the parameter and a dithering signal value, including by:
adjusting the parameter according to a machine position dependent waveform shaping function and a machine position feedback signal; and
computing the control output value as a sum of the adjusted parameter and the dithering signal value; and

control the position and velocity according to the control output value.

2. The circuit of claim 1 , wherein the machine is a motor, and computing the control output value comprises:
computing a motor velocity setpoint value according to a rotor angle position feedback pulse signal and the reference position signal;
computing the velocity error value according to the motor velocity setpoint value and a motor velocity feedback value; and
adjusting the parameter according to the motor velocity error value and the control function.

3. The circuit of claim 1 , wherein the machine is a motor, and controlling the position and velocity comprises:
generating an AC output signal according to a switching control signal to control the position and velocity; and
controlling a pulse width of the switching control signal according to the control output value.

4. A method of controlling a position and velocity of a machine, the method comprising:
controlling the position according to a reference position pulse signal;
computing a parameter according to a velocity error value and a control function;
computing a control output value as a sum of the parameter and a dithering signal value, including by:
adjusting the parameter according to a machine position dependent waveform shaping function and a machine position feedback signal; and
computing the control output value as a sum of the adjusted parameter and the dithering signal value; and

controlling the position and velocity according to the control output value.

5. The method of claim 4 , wherein the machine is a motor, and computing the control output value comprises:
computing a motor velocity setpoint value according to a rotor angle position feedback pulse signal and the reference position signal;
computing the velocity error value according to the motor velocity setpoint value and a motor velocity feedback value; and
adjusting the parameter according to the motor velocity error value and the control function.

6. The method of claim 4 , wherein the machine is a motor, and controlling the position and velocity comprises:
generating an AC output signal according to a switching control signal to control the position and velocity; and
controlling a pulse width of the switching control signal according to the control output value.

7. A light projection system comprising:
a color wheel;
a motor coupled to the color wheel;
an inverter coupled to the motor; and
control circuitry coupled to the inverter, the control circuitry comprising;
an electronic memory; and
a processor configured to execute program instructions stored in the electronic memory to:
control the position according to a reference position pulse signal;
compute a parameter according to a velocity error value and a control function;
compute a control output value as a sum of the parameter and a dithering signal value, including by:
adjusting the parameter according to a machine position dependent waveform shaping function and a machine position feedback signal; and
computing the control output value as a sum of the adjusted parameter and the dithering signal value; and

control the position and velocity according to the control output value.

8. The light projection system of claim 7 , wherein computing the control output value comprises:
computing a motor velocity setpoint value according to a rotor angle position feedback pulse signal and the reference position signal;
computing the velocity error value according to the motor velocity setpoint value and a motor velocity feedback value; and
adjusting the parameter according to the motor velocity error value and the control function.

9. The light projection system of claim 7 , wherein and controlling the position and velocity of the motor comprises:
generating an AC output signal according to a switching control signal to control the position and velocity; and
controlling a pulse width of the switching control signal according to the control output value.

10. The light projection system of claim 7 , wherein the inverter includes:
a power stage to generate an AC output signal according to a switching control signal to control the position and/or velocity; and
a gate driver to control a pulse width of the switching control signal according to the control output value.

11. The light projection system of claim 7 , wherein the control circuitry is configured to: implement an outer motor position control loop and an inner motor velocity control loop; and compute the parameter according to a motor velocity error value and a proportional-integral control function.

12. The light projection system of claim 11 , wherein the control circuitry is configured to implement the outer motor position control loop to control the position according to a reference position signal.

13. A method of controlling a position and velocity of a color wheel, the method comprising:
controlling the position according to a reference position pulse signal;
computing a parameter according to a velocity error value and a control function;
computing a control output value as a sum of the parameter and a dithering signal value, including by:
adjusting the parameter according to a position of the color wheel dependent waveform shaping function and a color wheel position feedback signal; and
computing the control output value as a sum of the adjusted parameter and the dithering signal value; and

controlling the position and velocity according to the control output value.

14. The method of claim 13 , wherein the color wheel includes a motor, and computing the control output value comprises:
computing a motor velocity setpoint value according to a rotor angle position feedback pulse signal and the reference position signal;
computing the velocity error value according to the motor velocity setpoint value and a motor velocity feedback value; and
adjusting the parameter according to the motor velocity error value and the control function.

15. The method of claim 13 , wherein the color wheel includes a motor, and controlling the position and velocity comprises:
generating an AC output signal according to a switching control signal to control the position and velocity; and
controlling a pulse width of the switching control signal according to the control output value.

16. A light projection system comprising:
a color wheel;
a motor coupled to the color wheel; and
control circuitry coupled to the inverter, the control circuitry comprising;
an electronic memory; and
a processor configured to execute program instructions stored in the electronic memory to:
control the position according to a reference position pulse signal;
compute a parameter according to a velocity error value and a control function;
compute a control output value as a sum of the parameter and a dithering signal value, includi

Assignees

• Texas Instruments Inc

Inventors

• Lakshmi Narasimha Rajan
• Magee David Patrick

Classifications

• G05B19/416 Primary

  characterised by control of velocity, acceleration or deceleration (G05B19/19 takes precedence) · CPC title

• G02B26/008

  in the form of devices for effecting sequential colour changes, e.g. colour wheels · CPC title

• G05B19/237

  with a combination of feedback covered by G05B19/232 - G05B19/235 · CPC title

• G05B19/258

  with a combination of feedback covered by G05B19/253 - G05B19/256 · CPC title

• G05B19/291

  the positional error is used to control continuously the servomotor according to its magnitude · CPC title