Using ODrive for autonomous rc car (Odometry and Vehicle Speed)

[alan]

I am building an autonomous RC car. I want to replace the donor vehicle’s motor with a new motor, encoder and an ODrive board to better control vehicle speed and have accurate wheel position inputs. The stock motor that came with the Exceed Blaze (donor vehicle) is approximately 28mm in diameter and 38 mm long.

Here is the motor I am thinking as a replacement: http://www.castlecreations.com/en/4wd-off-road-vehicles-up-to-1-75-lbs/0808-5300kv-motor-060-0038-00.

Here are some questions I have

1. Can I use ODrive rev 3.5 with this motor?
2. If I want to recharge the battery during regenerative braking, do I still need to install the 50W resistor?
3. Is there a better motor that I could fit as a replacement that is known to work with ODrive rev3.5 board?

[Richard_Parsons]

Hi Alan

1. That motor may not be a good fit for using with odrive due to its high KV of 5300. For example, running your odrive around 12V then the motors maximum speed would be around 63,000 RPM. This is far above what the motor is rated for and well above the 15,000 RPM limit of the CUI encoders commonly used with odrive. The odrive is ideally designed for high current and low Kv motors and so you will see best results with those.

2. If your odrive is connected directly to a battery and no 50W resistor is connected then all generated power during breaking will be absorbed by the battery. However you must be careful that doing so does not exceed the peak charging current of your battery or else you risk a fire. If I was you I would stick with the 50W resistor for the time being and revisit regen in the future when the feature is a bit further along.

3. Most people are currently using big out-runner motors with odrive as this makes the most use of its high current capability. For example, anything from the SK3 series with a KV under 1000 should work well.

Good luck!

[alan]

and well above the 15,000 RPM limit of the CUI encoders commonly used with odrive. The odrive is ideally designed for high current and low Kv motors and so you will see best results with those.

Thanks, will take a look!