Erpm Vesc

[Flocka Bilodeau]

Foran electric skateboard a strong Timeout Brake is not appropriate, since the rider would not be prepared to a sudden hard braking force. Only a very mild brake force can be handled by the unprepared rider and so should be the setting (e.g. 10A).

Throttle curves will let you adjust the behavior of your motor in reference to the throttle input. This can be a very useful feature to adjust the throttle response to your individual needs. To get started we recommend to use the "Natural" function first. The curves can be found in App Settings >>input device of usage (shown PPM).

This example shows more aggressive behavior to the negative throttle command (brake) and a slightly softer startup on positive throttle commands.

The softer your startup, the more aggressive it will get on the last bit of the throttle input and vice versa.

RPM limits can be a very useful feature. Possible application: You may want your bike, board, boat, car, etc. to reach a certain top speed only. The VESC-Tool allows you to specify a ERPM-Limit. Many people don't know what the difference between ERPM and RPM is and why VESC-Tol doesn't simply use an RPM value. The relation between RPM and ERPM has something to do with the motor you use and the VESC controller doesn't know the exact construction of your motor. But you may know it or you can find out easily.

All you need to know to calculate the ERPM is the number of pole pairs your motor features. Poles are e.g. the magnets of a BLDC-Outrunner/Inrunner motor. If your motor has 14 magnets installed, your motor has 7 pole pairs. In this case the RPM limit of your motor is simply the ERPM limit divided by 7.

When your motors feature temperature sensors, your VESC motor controller will cut off the power once the motors reach a pre-defined critical temperature. Same happens when the motor controller will get to hot. This feature protects your system from over temperature damages. The downside is, that you can't use your motor as a generator (brake) once it, or the ESC, or both got to hot.

The Acceleration Temperature Decrease feature allows you to lower the critical temperature cutoff for acceleration by x % (15% default), while the brakes continue to work at the defined full value.

The higher the value, the more safety range you will gain for the brakes, but the less you can push the system to its pre-defined temperature limits. If you set the value to high, you will experience power cutoffs during a regular system usage.

Since I am using a quite powerful motor, I am trying to figure out, how to set-up the VESC to increase the ramp-up time with the aim to accelerate the motor more slowly and smoothly (without huge accelerations). I am using only VESC tool, no additional PPM.

Additionally you can edit the PPM throttle map. I used 50% exponential on mine. This makes mine start spinning fast but decreases the max erpm as it passes 50% signal and it takes longer to reach max erpm. try different things ...

Is there any way to convert ERPM to RPM with no information about poles of motor. I want to calculate kv for my outrunner motor. I know kv = rpm/rated voltage. And in Vesc i only see erpm. I tried to calculate Kv from vesc terminal but it shows 0.0. I did it on foc mode.

It is not direct drive, for 10% duty cycle i have erpm = 700 and rpm=14 (how many times motor rotate per minute) (erpm/rpm = 50 ?). I cannot open the motor because I do not have the tools. Is there any other way to measure poles? I need poles for Kv and Kt because I know kV = wnoload(rpm)/ rated voltage. I know the rated voltage is 24V. All I need is rpm (vesc tool only shows erpm). Can i figure out kv. When i run kv command in Vesc Tools i get 330 which is in erpm then same thing here i need poles to get in rpm.

Did you get it. Did you figure it out? You can spin the motor by hand and feel each magnet per revolution or you can run (move a magnet) around the outside diameter feeling for poles. So if this is too fundamental of an answer.

12s 18650: 50.4v200kv = 10,080rpm6 pole pairs, erpm = 60,480Looks like I can just about make it, just throttling max rpm when the battery is full then. Keeping the 60k vesc limit should be enough for this to work, right?

Can anyone explain what happens while riding if you hit this limit? I recently had my diy build brake unexpectedly and throw me off and someone said this was the cause. would hitting the limit cause motors to brake?

I have had what I think is the same problem then @iamgeekusa. It would be extremely helpfully if I know what happened so I can fix it as I broke my collar bone due to the incident. I have a 190kv Motor from Tourque boards AKA diyelectricskateboard I also have there VESC. I set the erpm in VESC tool on FOC I set mine to 60,000 ermp. there was no button for Negative touque. Powering all this is 2x 5s in series (36V)

Note:I have an inkling that it is the erpm or something with my electronics but a few days after my accident I went back to the Crash site and there were some rocks. I do have 100mm all terrain wheels. Just thinking it could be something else.

Thank you for your advice . Yeah i can show the uart data on my serial port but i can't set the data yet i dont know why ? and ı want to control vesc6 with can here is some command that i wrote but ı dont know maths in behinds of vesc thank you again

Now that everything is built, configured, and installed, the odometry of the vehicle needs to be calibrated. The VESC receives input velocities in m/s and steering angles in radians. However the motor and servo requires commands in revolution per minute (RPM) and servo positions. The conversion parameters will need to be tuned to your specific car.

Hold the steering, and drive forward slowly and steadily until the car runs over the tape measure again and the rear axle realigns with the tape measure. Now the car should be in the opposite direction to where you started.

Compare the measured value to the value shown in the echoed message. If the distance reported by echo is larger, decrease the speed_to_erpm_gain value. Otherwise increase the gain. The change is usually on the order of thousands. Note that changing this value also changes the forward speed of teleop. Please drive carefully once the velocity is calibrated. If the forward speed when teleoping is too high, change the scale in human_control for drive-speed in joy_teleop.yaml.

For the Jetson RACECAR, we replace the stock TRAXXAS ESC with a Vedder Electronic Speed Controller (VESC). The major reason for the change is to gain full control at low speeds. The stock ESC puts the minimum vehicle speed at around 6 mph. Another reason is that the VESC is open source, which allows the curious to explore the motor controller implementation.

Note: The actual VESC firmware is available in binary form in the bldc-tool firmwares directory. If you are interested in building the VESC firmware from source, you can compile it from the bldc firmware source tree on Github.

The VESC is wired to the Jetson using a micro USB to USB-A cable. The USB cable normally communicates motor speed and steering angles between the Jetson and the VESC. The TRAXXAS steering servo is wired to the VESC servo header. In this application, a 90 degree, 3 pin female header helps with the wiring.

The robot has a deadman switch, the upper button (labeled LB) on the left horn of the game pad. Holding the deadman button, you can control the throttle with the left joystick, and the steering with the right joystick.

Just my two cent here. I once built my own Ambilight device. I used RGB addressable LED strip, where you have full control for every pixel in that strip. They came with variety of IC chips. One of them is ws2811. Mine was ws2812b.

I think Vedder add those .bin because he can connect the nunchuk and the ws2812 LEDs directly without any external microcontroller and with a minimal amount of external components.

Hi Alex,

The kernel rebuild was just for instructions on how to do rebuild onboard the Jetson TX2. I was using the VESC for the first time on the TX2 last week, and discovered the issue. Simple enough to fix, but a little frustrating that something that standard was missing out of the kernel build.

Any Update on this Case? I have the same issue with my jetson tx2. I am not able to connect with the gamepad Logitech F710 controller. The sudo jstest /dev/input/js0 is not successful although i run sudo apt-get install successfully.

We successfully installed the TX2 on your video at -sweep-lidar-software-install/ but after running $ roslaunch racecar teleop.launch: Error connecting to Hokuyo: Could not open network Hokuyo: 192.168.0.10. We tried a lot of ways but it still does not work.

I have set everything up and everything works perfectly except for one thing.

There is no steering control. With jstest I can execute and observe the servo command values from the F170 and when I plug the Servo in the wheels line up straight, but it seems nothing is being communicated from Focbox to the servo itself.

I used another battery which showed about 9v after charge. However, the motor still did not move. I could hear some click sound, but the wheels did not roll. I have put a video on youtube: =O0eDD4SOHlM. I could steer the car in the first half of the video. In the second half, I was trying the control the motor.

My vesc can control my moto sometimes,but it is not very stable.I can ensure the actual voltage of the battery higher than 8V.I use my joystick to control vesc,sometimes my moto can run for a little time, and sometimes the vesc flash red flights 4 times.So I do not know why :(.

Thanks for your reply!:)

The 4 red lights flashing usually means that the VESC has a hardware error issue. The 4 red lights also flash when the unit first boots up, so it could also be a loose connection. Does the steering work?

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