hello,I dont know that much about electronics so I am confused on some aspects of the connections
of a custom made motor driver,Iam using hip4081a driver IC which you can find its datasheet
below,I really dont know what values of capacitors to use wich are imbedded in the schematic ,
also what diodes to use and if it is ok for the power supply to provide high current,
as I said I dont know that much about electronics so maybe it all depends on the mosfets used in the gates
of the h-bridge but please if there are some typical values for those components I hope you can give some assistance ,though I am driving a 12 v dc motor,hope my description is enough ...thanks
The design choices depend on the details of the motor, the equipment the motor will be driving and how that equipment will be driven (rpm, torque, power).
This is not a project for a beginner. Instead, choose a suitable driver from those commercially available. Pololu has the best selection for hobbyists.
thanks for your reply ,well my problem was that MCU motor controller are slow,and I need such a motor controller whose response is fast and permenant ,and though I am not a beginner but yes I lack the knowledge of driving mosfets and driver IC s etc.. while the motor I am using is not that high power consuming motor,
running at 12v with 1000 rpm and stall torque of 7.5 kg-cm with stall current of 5.9 Ampere,and I am using
4 of them ,2 on each side of the robot connected in parallel,while all the robot's mass is 3 kg,so I need to single h-bridges each for one side ,and as I said building a motor driver is the best option,and my big problem is that building such a circuit needs an experienced person in such electronics ,that's why I was seeking help.
If you can provide me with a detailed schemetic I'll be able to build the driver ,and I am going to use
IRF3205 mosfet transistors ,I hope you could help me with this and thanks again
"well my problem was that MCU motor controller are slow,and I need such a motor controller whose response is fast and permenant ,and though I am not a beginner but yes I lack the knowledge of driving mosfets and driver IC s etc."
A slow motor controller sounds strange to me, but YMMV. Below is a DIY motor driver adventure that may give you a heads up on potential issues.
I know its hard to accomplish perfectly though I am still a high school student but is the VNH5019
motor driver fast enough like would it respond to logic inputs in some micro seconds for example
thanks after all
yes I continued my searches and found out its quite hard to make a practical motor drive,I was using the
bts7960a motor driver which I believe is too slow (MCU based btw)so this VNH5019 motor driver must be much faster right ?
I dont know if you can understand me but my robot takes many milliseconds (I cant give a precise number maybe 50 or in this range )to change the motors' direction and I am sure its not the fault of the arduino board
(mega2560) or the sensors ,I think that the motor driver is taking this much time to respond to Arduino inputs because it is MCU based
50 milliseconds for a motor to respond is reasonable. The moving parts have inertia. But you should never reverse a motor rapidly. If you do, it draws twice the stall current, possibly causing damage to the motor brushes, the wiring or other components.
Well I need a faster response ,my robot is moving at a fast speed and at some point it needs to change direction some how permanently, and Iam not chnaging it rapidly ,no ,but I think that changing the motor driver can really help and many of these robots move that way (its a sumo robot btw)
So is there an advice I might have not noticed
I really ask too many questions but dont you think it is possible to make the motors respond really fast or at
a maximum performance ,like is there a possible solution ,and if changing the bts7960b motor driver can help as I mentioned above(because so many people use different motor drivers and say it makes much more difference)
thanks...
"(because so many people use different motor drivers and say it makes much more difference)"
Have you asked those people what they use?
"Like if you can check the "zerolag" motor driver from jsumo ,what makes it different?"
Have you asked jusmo what makes it different? The forum may not be able to answer hypothetical or "they say" questions. Best you go to those sources for those types of questions.
I understand that,but I think I am not coming to a solution ,I have been researching for two weeks and cant find
a clue or even reach my question to guys like you,my problem is that the robot takes some time to react to sensors' inputs,all I want is to find some possible solutions to this problem and thought that the motor driver is the issue.If some one sees this what do you suggest to start looking for(in another words ,y robot moves on a specific ring too fast and I want instantaneous reaction to the inputs of the sensors) appreciate any help or advice thanks..
To decelerate or accelerate a motor faster takes more current, so you need to up the maximum current, simple as that. Nothing to do with the motor controller's being slow.
If you are giving all 4 motors their max current the only way to get more torque is by raising the supply voltage.
On sudden reversal your motors will need 12A (double their stall current ratings) initially as the back-EMF adds
to the supply voltage (they see 24V at that point).
You didn't say what wheel radius you are using, but if the 0.735Nm of each motor drives a 2.5cm radius wheel that's about 120N available to drive the thing, 1000rpm means 2.5m/s, to decelerate to standstill from full speed
theoretically takes 2.5 / (120/3) = 62.5ms
This broadly agrees with your 50ms figure. You cannot change the laws of physics, and anyway your wheels
would lose traction before you managed to get the 4g acceleration its theoretically capable of.
You need an understanding of basic mechanics to design robots. I would say your setup is reasonable though,
the motors can provide rather more torque than the wheels can transmit, so its not under powered and 2.5m/s
isn't slow either.