Search found 931 matches

by rew
27 Mar 2016, 11:20
Forum: General
Topic: Is it possible to use the vesc for wheelchair hub motor
Replies: 9
Views: 2135

Re: Is it possible to use the vesc for wheelchair hub motor

Matt, if the motors are BLDC, then I would say that VESC is a resonable choice. At first I thought the motors were oldfashioned DC motors.)

Can you provide a link to the motors that you have?
by rew
27 Mar 2016, 11:16
Forum: General
Topic: Long motor wires (vs. long battery)
Replies: 10
Views: 2766

Re: Long motor wires (vs. long battery)

Something that I've come to realize only recently while working more intimately with the VESC is that it is quite possible to have much larger motor-current than you think. (some details changed to protect the innocent...). A friend had a 20A motor and a 30A ESC. The motor was rated at 50V and 10000...
by rew
27 Mar 2016, 09:56
Forum: General
Topic: VESC at high Voltage (and KV)
Replies: 14
Views: 4564

Re: VESC at high Voltage (and KV)

Hello Akira, you should pick your motors based on rpm they are meant to run at and by their efficiency curve (which is a function of rpm): http://content.vexrobotics.com/vexpro/images/motor-data/dc-motor-intro-motor-b-2.PNG The graph shows a decreasing "current" line that starts at the st...
by rew
27 Mar 2016, 09:37
Forum: Feature Requests
Topic: ADC channel configuration.
Replies: 3
Views: 1542

ADC channel configuration.

Benjamin: on my hardware the current sense channels were assigned differently than on your hardware. So I changed things around and got "weird" (i.e. not working) results. Spent a week trying to figure out what was wrong. In the end it turns out that the assignment of the channels happens ...
by rew
27 Mar 2016, 09:28
Forum: Feature Requests
Topic: Thoughts on other FET’s?
Replies: 19
Views: 5887

Re: Thoughts on other FET’s?

In the smaller packages you can only dissipate about 1W before things get too hot. The bigger tolerate about 2W. This means that the RDSon specification is VERY important. So for the SO8, you roughly get P = I^2.R or I = SQRT (P/R) = sqrt(128) = 11A max. My quick-and-dirty calculation would lead to ...
by rew
27 Mar 2016, 09:12
Forum: FOC
Topic: Question about ADC Injected channelks configuration
Replies: 5
Views: 2130

Re: Question about ADC Injected channelks configuration

There is code to sample the current twice and then average the results. It looks to me as if this was an attempt to get less noise, but it was abandoned because it didn't help much. So the option to sample twice is turned off by default. The second set of initializations (with the "2" in t...
by rew
27 Mar 2016, 09:08
Forum: FOC
Topic: Position control with an overlaid velocity control
Replies: 1
Views: 806

Re: Position control with an overlaid velocity control

I would say: if you need an industrial solution, get an industrial motor controller. But you'll have to bring a full bag of dollars. If you want a cheaper solution, VESC may come into play. But VESC is limited to about 50A and 50V. That is enough for your "about 1kW" but if your motor is &...
by rew
27 Mar 2016, 09:04
Forum: FOC
Topic: FOC: Motor oscillating back and forth
Replies: 9
Views: 4343

Re: FOC: Motor oscillating back and forth

I made the same mistake. The thing that I didn't understand is that I could make it "a little more stable" by increasing the Ki enormously. It is starting to make sense now. By increasing the Ki in the current control loop, I'm making that slower, so the bad parameters in the speed control...
by rew
27 Mar 2016, 08:55
Forum: Hardware Problems
Topic: DRV Fault GVDD
Replies: 9
Views: 3278

Re: DRV Fault GVDD

As far as I know, the firmware is "enforcing" a specific average voltage on each of the motor leads by setting a PWM value for each of the motor leads. Now classical PWM is on/off, but in this case, we're switching between "drive low" and "drive high". So each PWM cycle...
by rew
27 Mar 2016, 08:11
Forum: FOC
Topic: VESC v4.10 and battery cable length
Replies: 7
Views: 2720

Re: VESC v4.10 and battery cable length

Rfvito, that is not true. I have a 4700 uF capacitor. When I accelerate the current spikes to 20A or something like that. Reworking the capacitor formula, i = C dU / dt into dt = C dU / I, we can calculate that it takes 0.2 miliseconds for 20A to cause a 1V drop across the capacitor. The current spi...

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