esp-idf/examples/peripherals/mcpwm/mcpwm_brushed_dc_control

Supported Targets	ESP32	ESP32-S3

MCPWM Brushed DC Motor Example

(See the README.md file in the upper level 'examples' directory for more information about examples.)

This example mainly illustrates how to drive a brushed DC motor by generating two specific PWM signals. This example assumes an L298N H-bridge driver is used to provide the needed voltage and current for brushed DC motor. This example also implements a motor control command console such that users can configure and control the motors at run time using console commands.

How to Use Example

Before project configuration and build, be sure to set the correct chip target using idf.py set-target <chip_name>.

Hardware Required

• A development board with any Espressif SoC which features MCPWM and PCNT peripheral (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
• A USB cable for Power supply and programming
• A separate 12V power supply for brushed DC motor and H-bridge (the voltage depends on the motor model used in the example)
• A motor driving board to transfer pwm signal into driving signal
• A brushed DC motor, e.g. 25GA370
• A quadrature encoder to detect speed

Connection :

                                     Power(12V)
                                         |
                                         v
+----------------+             +--------------------+
|                |             |      H-Bridge      |
|            GND +------------>|                    |      +--------------+
|                |             |                    |      |              |
|         GPIO15 +----PWM0A--->| IN_A         OUT_A +----->|   Brushed    |
|                |             |                    |      |     DC       |
|         GPIO16 +----PWM0B--->| IN_A         OUT_B +----->|    Motor     |
|                |             |                    |      |              |
| ESP            |             +--------------------+      |              |
|                |                                         +------+-------+
|                |                                                |
|                |             +--------------------+             |
|         VCC3.3 +------------>|      Encoder       |             |
|                |             |                    |             |
|            GND +------------>|                    |<------------+
|                |             |                    |
|         GPIO18 |<---PhaseA---+ C1                 |
|                |             |                    |
|         GPIO19 |<---PhaseB---+ C2                 |
|                |             |                    |
+----------------+             +--------------------+

NOTE: If some other GPIO pins (e.g., 13/14) are chosen as the PCNT encoder pins, flashing might fail while the wires are connected. If this occurs, please try disconnecting the power supply of the encoder while flashing.

Build and Flash

Run idf.py -p PORT flash monitor to build, flash and monitor the project.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

Run the example, you will see the following output log:

...
Testing brushed motor with PID...
initializing mcpwm gpio...
Configuring Initial Parameters of mcpwm...

Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
 =================================================================
 |             Example of Motor Control                          |
 |                                                               |
 |  1. Try 'help', check all supported commands                  |
 |  2. Try 'config' to set control period or pwm frequency       |
 |  3. Try 'pid' to configure pid paremeters                     |
 |  4. Try 'expt' to set expectation value and mode              |
 |  5. Try 'motor' to start motor in several seconds or stop it  |
 |                                                               |
 =================================================================

Default configuration are shown as follows.
You can input 'config -s' to check current status.
 -----------------------------------------------------------------
                  Current Configuration Status

 Configuration
       Period = 10 ms	PID = enabled

 PID - Increment
       Kp = 0.800	Ki = 0.000	Kd = 0.100

 Expectation - Triangle
       init = 30.000	max = 50.000	min = -50.000	pace = 1.000

 MCPWM
       Frequency = 1000 Hz

 Motor
       Running seconds = 10
 -----------------------------------------------------------------

 mcpwm-motor>

Check all supported commands and their usages

• Command: help

mcpwm-motor> help
help
  Print the list of registered commands

config  config -s
  Enable or disable PID and set motor control period
  --pid=<y|n>  Enable or disable PID algorithm
  -T, --period=<ms>  Set motor control period
  -s, --show  Show current configurations

expt  expt -i <duty> -m <fixed/tri/rect> -p <double> --max <duty> --min -50<duty>
  Set initial value, limitation and wave mode of expectation. Both dynamic and
  static mode are available
  --max=<duty>  Max limitation for dynamic expectation
  --min=<duty>  Min limitation for dynamic expectation
  -p, --pace=<double>  The increasing pace of expectation every 50ms
  -i, --init=<duty>  Initial expectation. Usually between -100~100
  -m, --mode=<fixed/tri/rect>  Select static or dynamic expectation wave mode. 'fixed' for static, 'tri' for triangle, 'rect' for rectangle

pid  pid -p <double> -i <double> -d <double> -t <loc/inc>
  Set parameters and type for PID algorithm
  -p, --kp=<double>  Set Kp value for PID
  -i, --ki=<double>  Set Ki value for PID
  -d, --kd=<double>  Set Kd value for PID
  -t, --type=<loc/inc>  Select locational PID or incremental PID

motor  motor -u 10
  Start or stop the motor
  -u, --start=<seconds>  Set running seconds for motor, set '0' to keep motor running
  -d, --stop  Stop the motor

Check status

• Command: config -s

 mcpwm-motor> config -s

 -----------------------------------------------------------------
                  Current Configuration Status

 Configuration
       Period = 10 ms	PID = enabled

 PID - Increment
       Kp = 0.800	Ki = 0.000	Kd = 0.100

 Expectation - Triangle
       init = 30.000	max = 50.000	min = -50.000	pace = -1.000

 MCPWM
       Frequency = 1000 Hz

 Motor
       Running seconds = 10
 -----------------------------------------------------------------

Enable or disable PID

• Command: config --pid <y/n>
• 'y' - enable PID
• 'n' - disable PID

mcpwm-motor> config --pid n
config: pid disabled
mcpwm-motor> config --pid y
config: pid enabled

Set PID parameters

• Command: pid -p <double> -i <double> -d <double> -t <loc/inc>
• 'p' - proportion value
• 'i' - integral value
• 'd' - differential value
• 't' - PID calculation type (locational or incremental).

mcpwm-motor> pid -p 0.8 -i 0.02 -d 0.1 -t inc
pid: kp = 0.800
pid: ki = 0.020
pid: kd = 0.100
pid: type = increment

Set expectation parameters

• Command: expt -i <duty> -m <fixed/tri/rect> -p <double> --max <duty> --min <duty>
• 'i' - initial duty if you set mode 'fixed'
• 'm' - expectation mode. 'fixed' means the expectation will never change, 'tri' means the expectation will changes with trigonometric wave, 'rect' means the expectation will changes with rectangular wave
• 'p' - the setp size of expectation changed in every 50ms, it can adjust the expectation changing speed
• 'max' - the maximum limitation of expectation
• 'min' - the minimum limitation of expectation

mcpwm-motor> expt -i 40 -m rect -p 1.5 --max 80 --min -60
expt: init = 40.000
expt: max = 80.000
expt: min = -60.000
expt: pace = 1.500
expt: mode = rectangle

Start or stop motor

• Command: motor -u <sec>
• Command: motor -d
• 'u' - start the motor in seconds, if is 0, the motor won't stop until 'motor -d' is inputed
• 'd' - stop the motor right now

mcpwm-motor> motor -u 10
motor: motor starts to run in 10 seconds
mcpwm-motor> 1
2
3
4
5
6
7
8
9
10

Time up: motor stoped

Troubleshooting

• Make sure your ESP board and H-bridge module have been connected to the same GND panel.

For any technical queries, please open an issue on GitHub. We will get back to you soon.