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    voxl Tmotor f55 esc

    ESCs
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    • Alex KushleyevA
      Alex Kushleyev ModalAI Team @ErezI
      last edited by

      @ErezI

      We recently updated the parameter structure in the ESC params. The ESCs you have are using older params. If you wanted to verify or update those params, please use the following version of voxl-esc tools : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/v1.1.1

      If you want to use the latest params, a firmware update and param update is required.
      You can use the latest voxl-esc tools : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/v1.2.2

      update the firmware on all ESCs:
      ./voxl-esc-upload-firmware-all.sh firmware/modalai_esc_firmware_tmotor_f55a_revc_v0_38_9b6d54b6.bin

      At this point the ESCs will make a sad tone because the params will be invalid. Now update the params to the latest default params for the tmotor ESC.
      ./voxl-esc-upload-params.py --params-file ../voxl-esc-params/FPV_RevB/FPV_RevB.xml

      After this, you should have the ESC updated firmware and params to the latest. Next you can diff your desired params against the latest params you just loaded, and create a new version of your params.

      I noticed that you have pretty high kp and ki values. If you are just starting out, i would suggest setting kp=0 and ki=0, this will result in performance close to a off-the-shelf ESC. having gains set too high could result in vibrations or motors heating up, it will require some more careful testing.

      Additionally, i noticed that your tuning params do not have a lot of precision, which will result in incorrect curve. You should have at least 3 or preferably 6 decimal places for each of a0, a1, a2 to avoid any error. You can copy paste them directly from the calibration procedure.

      <param name="pwm_vs_rpm_curve_a0" value="870.0"/>
      <param name="pwm_vs_rpm_curve_a1" value="0.5"/>
      <param name="pwm_vs_rpm_curve_a2" value="3.0e-06"/>

      Alex

      E 4 Replies Last reply Reply Quote 0
      • E
        ErezI @Alex Kushleyev
        last edited by

        @Alex-Kushleyev

        Alex Hi

        Thanks for your fast & supporting respond.

        1.We got negative values for a0 (-500 to -1000) and not your recommended positive value
        <param name="pwm_vs_rpm_curve_a0" value="870.0"/>
        <param name="pwm_vs_rpm_curve_a1" value="0.5"/>
        <param name="pwm_vs_rpm_curve_a2" value="3.0e-06"/>

        Should a0 be a negative value (-870) or a positive on (a correctness value?)?

        2.We got different parameter values to the curves while running multiple calibration tests t
        o the same ESCx-Motx couples,
        and of course different values testing a different ESCx-Motx couples.

        What should be (how to choose/ calculate) the right a0,a1 & a2 values for the single uploaded parameters file (avg?)

        20230712-150720_ESC_#3_Volt_vs_RPM.jpg 20230712-150654_ESC_#2_Volt_vs_RPM.jpg 20230712-150617_ESC_#1_Volt_vs_RPM.jpg 20230712-150539_ESC_#0_Volt_vs_RPM.jpg 20230712-150233_ESC_#0_Volt_vs_RPM.jpg

        Thanks Erez

        ps

        New voxl-esc-calibrate.py with a0-a2 inside the graphs and
        created under the logs folder

        cat ./voxl-esc-calibrate2.py

        Copyright (c) 2020 ModalAI Inc.

        Redistribution and use in source and binary forms, with or without

        modification, are permitted provided that the following conditions are met:

        1. Redistributions of source code must retain the above copyright notice,

        this list of conditions and the following disclaimer.

        2. Redistributions in binary form must reproduce the above copyright notice,

        this list of conditions and the following disclaimer in the documentation

        and/or other materials provided with the distribution.

        3. Neither the name of the copyright holder nor the names of its contributors

        may be used to endorse or promote products derived from this software

        without specific prior written permission.

        4. The Software is used solely in conjunction with devices provided by

        ModalAI Inc.

        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

        AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

        ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

        LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

        CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

        SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

        INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

        CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

        ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

        POSSIBILITY OF SUCH DAMAGE.

        For a license to use on non-ModalAI hardware, please contact license@modalai.com

        from voxl_esc_setup_paths import *
        voxl_esc_setup_paths()

        from libesc import *
        from esc_scanner import EscScanner
        import time
        import numpy as np
        import argparse

        parser = argparse.ArgumentParser(description='ESC Calibration Script')
        parser.add_argument('--device', required=False, default=None)
        parser.add_argument('--baud_rate', required=False, default=None)
        parser.add_argument('--id', type=int, required=False, default=0)
        parser.add_argument('--pwm-min', type=int, required=False, default=10)
        parser.add_argument('--pwm-max', type=int, required=False, default=90)
        parser.add_argument('--pwm-step', type=int, required=False, default=1)
        parser.add_argument('--pwm-step-duration', type=float, required=False, default=0.5) #seconds
        args = parser.parse_args()

        devpath = args.device
        baudrate = args.baud_rate
        esc_id = args.id
        PWM_MIN = args.pwm_min
        PWM_MAX = args.pwm_max
        PWM_STEP = args.pwm_step
        STEPDURATION = args.pwm_step_duration

        quick scan for ESCs to detect the port

        scanner = EscScanner()
        (devpath, baudrate) = scanner.scan(devpath, baudrate)

        if devpath is not None and baudrate is not None:
        print('INFO: ESC(s) detected on port: ' + devpath + ', baud rate: ' + str(baudrate))
        else:
        print('ERROR: No ESC(s) detected, exiting.')
        sys.exit(1)

        #check input arguments
        if PWM_MIN < 10 or PWM_MIN > 50:
        print('ERROR: Minimum power must be between 10 and 50')
        sys.exit(1)

        if PWM_MAX < 10 or PWM_MAX > 100:
        print('ERROR: Maximum power must be between 10 and 100')
        sys.exit(1)

        if PWM_MAX < PWM_MIN:
        print('ERROR: Maximum power must be greater than minimum power')
        sys.exit(1)

        TRANSITIONTIME = 0.40

        create ESC manager and search for ESCs

        try:
        esc_manager = EscManager()
        esc_manager.open(devpath, baudrate)
        except Exception as e:
        print('ERROR: Unable to connect to ESCs :')
        print(e)
        sys.exit(1)

        wait a little to let manager find all ESCs

        time.sleep(0.25)
        num_escs = len(esc_manager.get_escs())
        if num_escs < 1:
        print('ERROR: No ESCs detected--exiting.')
        sys.exit(1)

        esc = esc_manager.get_esc_by_id(esc_id)
        if esc is None:
        print('ERROR: Specified ESC ID not found--exiting.')
        sys.exit(1)

        warn user

        print('WARNING: ')
        print('This test requires motors to spin at high speeds with')
        print('propellers attached. Please ensure that appropriate')
        print('protective equipment is being worn at all times and')
        print('that the motor and propeller are adequately isolated')
        print('from all persons.')
        print('')
        print('For best results, please perform this test at the')
        print('nominal voltage for the battery used.')
        print('')
        response = input('Type "Yes" to continue: ')
        if response not in ['yes', 'Yes', 'YES']:
        print('Test canceled by user')
        sys.exit(1)

        get ESC software version. sw_version < 20 means gen1 ESC, otherwise gen2

        sw_version = esc.get_versions()[0]

        esc_manager.enable_protocol_logging()

        spin up

        esc_manager.set_highspeed_fb(esc_id) #tell ESC manager to only request feedback from this ID (so we get feedback 4x more often)
        esc.set_target_power(10)
        t_start = time.time()
        while time.time() - t_start < 1.0:
        time.sleep(0.05)
        esc_manager.send_pwm_targets()

        measurements = []
        t_test_start= time.time()

        ramp up from min to max

        pwm_now = PWM_MIN #10
        while pwm_now <= PWM_MAX:
        esc.set_target_power(pwm_now)
        t_start = time.time()
        print('')
        while time.time() - t_start < STEPDURATION:
        time.sleep(0.01)
        esc_manager.send_pwm_targets()
        if pwm_now >= PWM_MIN and time.time() - t_start >= TRANSITIONTIME:
        measurements.append(
        [esc.get_power(), esc.get_rpm(), esc.get_voltage(), esc.get_current()])
        print('POW: %d, RPM: %.2f, Voltage: %.2fV, Current: %.2fA' % (esc.get_power(), esc.get_rpm(), esc.get_voltage(), esc.get_current()))
        pwm_now += PWM_STEP

        close the manager and UART thread

        esc_manager.close()
        t_test_stop= time.time()
        print ('INFO: Test took %.2f seconds' % (t_test_stop-t_test_start))

        #d_date=datetime.datetime.now()
        d_date="{:%Y%m%d-%H%M%S}".format(datetime.now())
        print ("date="+str(d_date))

        parse measurements

        pwms = [data[0] for data in measurements]
        rpms = [data[1] for data in measurements]
        voltages = [data[2] for data in measurements]
        currents = [data[3] for data in measurements]

        #reported power is 0-100, but in ESC firmware it is 0-1000
        motor_voltages = [pwms[i]10.0/999.0(voltages[i]*1000) for i in range(len(pwms))]

        linear fit or quadratic fit

        ply = np.polyfit(rpms, motor_voltages, 2)
        motor_voltages_fit = np.polyval(ply, rpms)

        print corresponding params

        print('Quadratic fit: motor_voltage = a2rpm_desired^2 + a1rpm_desired + a0')
        print(' a0 = ' + str(ply[2]))
        print(' a1 = ' + str(ply[1]))
        print(' a2 = ' + str(ply[0]))
        print('ESC Params (after scaling):')
        print(' pwm_vs_rpm_curve_a0 = ' + str(ply[2]))
        print(' pwm_vs_rpm_curve_a1 = ' + str(ply[1]))
        print(' pwm_vs_rpm_curve_a2 = ' + str(ply[0]))

        plot results if possible

        try:
        import matplotlib.pyplot as plt
        except:
        print('WARNING: In order to plot the results, install the Python "matplotlib" module')
        sys.exit(0)

        plot the results

        plt.plot(rpms, motor_voltages, 'bo')
        plt.tight_layout()
        plt.plot(rpms, motor_voltages_fit)
        print ('Motor Voltage vs. RPM Test')
        plt.xlabel('Measured RPM')
        plt.ylabel('Commanded Motor Voltage (mV)')
        plt.title('Motor Voltage vs. RPM Test')
        plt.legend(['Data', 'Fit'], loc=2)
        plt.ylim([0, np.max(motor_voltages)+1000])
        plt.tight_layout()
        print ('Motor Voltage vs. RPM Test')
        plt.tight_layout()

        plot corresponding params

        plt.figtext(0.5, 0.01, "Quadratic fit: motor_voltage = a2rpm_desired^2 + a1rpm_desired + a0", ha="center", fontsize=10, bbox={"facecolor":"orange", "alpha":0.5, "pad":5})
        plt.figtext(0.2, 0.97, 'a0=%.8f' % ply[2], ha="center", fontsize=10, bbox={"facecolor":"green", "alpha":0.5, "pad":5})
        plt.figtext(0.5, 0.97, 'a1=%.8f' % ply[1], ha="center", fontsize=10, bbox={"facecolor":"green", "alpha":0.5, "pad":5})
        plt.figtext(0.8, 0.97, 'a2=%.8f' % ply[0], ha="center", fontsize=10, bbox={"facecolor":"green", "alpha":0.5, "pad":5})
        plt.tight_layout()

        plt.savefig('./logs/'+str(d_date)+'ESC#'+str(esc_id)+'_Volt_vs_RPM.jpg',bbox_inches='tight')
        #time.sleep(2)

        plt.figure()

        plt.plot(pwms, rpms, 'bo')
        print ('RMP vs. PWM Test')
        plt.xlabel('Commanded PWM (x/100)')
        plt.ylabel('Measured RPM')
        plt.title('RPM vs. PWM Test')
        plt.tight_layout()

        plot corresponding params

        plt.figtext(0.5, 0.01, "ESC Params (after scaling):", ha="center", fontsize=10, bbox={"facecolor":"orange", "alpha":0.5, "pad":5})
        plt.figtext(0.3, 0.97, 'a0=%.8f' % ply[2], ha="center", fontsize=10, bbox={"facecolor":"yellow", "alpha":0.5, "pad":5})
        plt.figtext(0.6, 0.97, 'a1=%.8f' % ply[1], ha="center", fontsize=10, bbox={"facecolor":"yellow", "alpha":0.5, "pad":5})
        plt.figtext(0.9, 0.97, 'a2=%.8f' % ply[0], ha="center", fontsize=10, bbox={"facecolor":"yellow", "alpha":0.5, "pad":5})

        plt.savefig('./logs/'+str(d_date)+'ESC#'+str(esc_id)+'_RPM_vs_PWM.jpg',bbox_inches='tight')
        plt.show()
        plt.close()

        1 Reply Last reply Reply Quote 0
        • E
          ErezI @Alex Kushleyev
          last edited by

          @Alex-Kushleyev

          Hi Alex,

          I replaced the F55A ESCs firmware from version 33 to version 38
          (modalai_esc_firmware_tmotor_f55a_revc_v0_38_9b6d54b6.bin),
          and used he new code version (v1.2.2) &
          also used the new XML file (FPV_RevB.xml renamed to mpd_params.xml)
          but I got the same errors:

          user@user-CF-54-3:/data/voxl-esc-v1.2.2/voxl-esc-tools$ sudo python3 ./voxl-esc-upload-params.py --params-file ../../voxl-esc-add-new-params/voxl-esc-params/MPD/mpd_params.xml
          Detected Python version : 3.8.10 (default, May 26 2023, 14:05:08)
          [GCC 9.4.0]
          Found voxl-esc tools bin version: 1.2

          INFO: Params file name : ../../voxl-esc-add-new-params/voxl-esc-params/MPD/mpd_params.xml
          INFO: Params file size : 6835 bytes

          INFO: All COM ports:
          /dev/ttyS4 : n/a
          /dev/ttyUSB0 : TTL232R
          INFO: UART Port Candidates:
          /dev/ttyUSB0
          INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 2000000
          INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 250000
          INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 921600
          INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 230400
          INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 57600
          INFO: ESC(s) detected on port: /dev/ttyUSB0, baud rate: 57600
          INFO: ESCs detected:
          INFO: ---------------------
          ID: 0, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
          ID: 1, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
          ID: 2, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
          ID: 3, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)

          INFO: Loading XML config file...
          WARNING: Tune Parameter "tone_freqs_10hz" incompatible
          WARNING: Tune Parameter "tone_times_ms" incompatible
          Traceback (most recent call last):
          File "./voxl-esc-upload-params.py", line 124, in <module>
          esc.params.parse_xml_string( xml_string )
          File "./tmp/voxl-esc-tools-bin-export-1.2/libesc/params.py", line 518, in parse_xml_string
          File "./tmp/voxl-esc-tools-bin-export-1.2/libesc/params.py", line 935, in set_packet_metadata
          File "./tmp/voxl-esc-tools-bin-export-1.2/libesc/params.py", line 249, in update_crc
          File "./tmp/voxl-esc-tools-bin-export-1.2/libesc/params.py", line 165, in get_param_bytes_for_crc
          File "./tmp/voxl-esc-tools-bin-export-1.2/libesc/params.py", line 85, in byteify
          struct.error: pack expected 12 items for packing (got 4)

          Erez

          1 Reply Last reply Reply Quote 0
          • E
            ErezI @Alex Kushleyev
            last edited by

            @Alex-Kushleyev

            Alex,

            more info

            /data/voxl-esc-v1.2.2/voxl-esc-tools$ sudo ./voxl-esc-verify-params.py
            Detected Python version : 3.8.10 (default, May 26 2023, 14:05:08)
            [GCC 9.4.0]
            Found voxl-esc tools bin version: 1.2
            INFO: All COM ports:
            /dev/ttyS4 : n/a
            /dev/ttyUSB0 : TTL232R
            INFO: UART Port Candidates:
            /dev/ttyUSB0
            Found previous connection information in .voxl_esc_cache ..
            Prioritizing /dev/ttyUSB0 @ 57600
            INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 57600
            INFO: ESC(s) detected on port: /dev/ttyUSB0, baud rate: 57600
            ID config CRC mismatch 60163 != 0
            ERROR: Params for ID 0 are invalid!
            ID config CRC mismatch 60163 != 0
            ERROR: Params for ID 1 are invalid!
            ID config CRC mismatch 60163 != 0
            ERROR: Params for ID 2 are invalid!
            ID config CRC mismatch 60163 != 0
            ERROR: Params for ID 3 are invalid!
            ERROR: Some params are invalid or not the same!
            Number of ESCs expected : 4
            Number of ESCs found : 4
            Number of invalid params : 4
            Number of matched params : 4

            1 Reply Last reply Reply Quote 0
            • E
              ErezI @Alex Kushleyev
              last edited by

              @Alex-Kushleyev

              Alex,

              With the new file it works:

              sudo python3 ./voxl-esc-upload-params.py --params-file ../voxl-esc-params/FPV_RevB/FPV_RevB.xml
              Detected Python version : 3.8.10 (default, May 26 2023, 14:05:08)
              [GCC 9.4.0]
              Found voxl-esc tools bin version: 1.2

              INFO: Params file name : ../voxl-esc-params/FPV_RevB/FPV_RevB.xml
              INFO: Params file size : 7663 bytes

              INFO: All COM ports:
              /dev/ttyS4 : n/a
              /dev/ttyUSB0 : TTL232R
              INFO: UART Port Candidates:
              /dev/ttyUSB0
              Found previous connection information in .voxl_esc_cache ..
              Prioritizing /dev/ttyUSB0 @ 57600
              INFO: Scanning for ESC firmware: /dev/ttyUSB0, baud: 57600
              INFO: ESC(s) detected on port: /dev/ttyUSB0, baud rate: 57600
              INFO: ESCs detected:
              INFO: ---------------------
              ID: 0, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
              ID: 1, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
              ID: 2, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)
              ID: 3, SW: 38, HW: 33: Blheli32 4-in-1 ESC Type B (Tmotor F55A PRO G071)

              INFO: Loading XML config file...
              INFO: Uploading params...
              -- board config
              -- id config
              -- uart config
              -- tune config
              DONE
              INFO: Resetting ESCs...
              DONE

              I'll change the relevant parameters to fit our motor's type.

              Thanks

              Erez

              Alex KushleyevA 1 Reply Last reply Reply Quote 0
              • Alex KushleyevA
                Alex Kushleyev ModalAI Team @ErezI
                last edited by

                @ErezI

                When it comes to comparing the quadratic curve fits, it is difficult to look at just the coefficients and compare them. If you have multiple tests, you should plot the quadratic plots on the same figure and see how repeatable they are. What may seem like a noticeable variation in the coefficients, could still result in curves that are very similar.

                By the way, you should not just average values of a0, a1, and a2 to get a0_average, a1_average, and a2_average, as this will result in wrong curve. If you would like to find an average of all 4 runs, then you can just create a quadratic fit of all the points from the 4 data sets - that is the proper way to do it. However, if after plotting the 4 curves they look very similar, you can use any of the 4 individual fits. The PI (Proportional Integral) controller on the ESC will compensate for minor deviations.

                The error you saw with params not being valid was due to the latest version of voxl-esc tools using new parameter structure. So the solution is (which is what you already figured out) to update the firmware and params to latest. This type of change does not happen too often. We will add this to documentation to make this clear.

                Alex

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