MisterBill2
- Joined Jan 23, 2018
- 18,477
Probably an entirely different speed controller package that uses PWM and is able to handle the motor current load. Not simple.
Thanks Mr Bill, I'm here to learn so why is this not simple?Probably an entirely different speed controller package that uses PWM and is able to handle the motor current load. Not simple.
Controlling the voltage in steps like that won't control the speed well. If the motor is driving a heavy load, e.g when the golf cart is going over rough ground or uphill, it will slow down and draw more current.I was thinking it would be possible to use a voltage regulator circuit to control the speed.
I have seen write-ups about a couple of them that use what I think is an IR flashing beacon clipped to the user's belt.That makes the system a lot more complex because now it needs to track and steer. I am guessing that it steers by the speed of the two larger wheels and that the balance wheel castors as it turns. I am guessing that the TS steers theirs with either the handle or a short leash. The original complaint was that the preset speed settings were either too slow or two fast, requiring constant adjusting of the speed control.I have a dumb question. How do you steer this? Doesn't it need you holding on to the handle to steer it, like most small golf bag carts?
theres nothing wrong with a variable voltage divider in my mind. no arduino.The control will be vastly more efficient if the otor speed is controlled using PWM instead of a variable resistor. And the effort of moving will be less if it is pulled, not pushed.
What is totally missing is a detailed view of the drive scheme. If both wheels are driven through a differential, or by two motors, different methods will be required. It is obvious from the photo that the front wheel does not steer and can not swivel and so evidently steering is intended to be a strong-arm method. Possibly a dual motor drive system will allow a bit of directional control, but even then it will not be very satisfactory because it will require skidding the front wheel.
Theory is one thing; practicalities are something else.theres nothing wrong with a variable voltage divider in my mind
For direct motor speed control a voltage divider places a resistor in parallel with the motor load, and that is not efficient at all.Theory is one thing; practicalities are something else.
As long as you don't mind wasting battery power in heat. PWM does it without wasting power from the battery. That is why RC models use PWM instead of a rheostat.I think t
theres nothing wrong with a variable voltage divider in my mind. no arduino.
your supposed to use some very low resistance wire, like nychrome, and then they do put a small load on the motor but the torque loss in minimal, it is present tho, yes.For direct motor speed control a voltage divider places a resistor in parallel with the motor load, and that is not efficient at all.
If the control is for setting the control input of a motor drive controller, that is quite totally different. An earlier post commented that the limited number of preset speeds were not suitable but it gave no hint about the actual control system, only that the choices were "too fast or too slow".
So the controller may already be a PWM system with poor control options.
Yes, that was my initial thought. I wanted to build a circuit to directly control the existing single-driver motor on the axel of the cart. I'm a software guy (don't know much about microelectronics) and when you guys start talking about resistance, voltage, pwm, ohms, etc. I failed to understand how to implement your're suggesting.You probably already know but->
Every once in a while someone comes along who sounds savvy enough that they get talked to like they have a basic understanding when they don't. I think you might be one of them. So let me break this down.Yes, that was my initial thought. I wanted to build a circuit to directly control the existing single-driver motor on the axel of the cart. I'm a software guy (don't know much about microelectronics) and when you guys start talking about resistance, voltage, pwm, ohms, etc. I failed to understand how to implement your're suggesting.
You're indicating pretty strongly that this is something you've already done/written but that doesn't seem to jive with your apparent lack of any concept of the physical side. The circuits and the software are things that, if I were designing this, would be designed in parallel. Actually I'm not sure how I would go about it any other way. One informs the other. So can you clarify what among the following quote is something you've actually written already and what is just something you plan to write?That's why I ended up using a Raspberry and writing software.
Raspberry Pi is gross overkill for this project, and not even in a good way. I get that you want a programmable approach to the solution and you can still have that, no problem, for much cheaper and without waiting 3 minutes for your golf cart's OS to boot up. Why did you abandon the Arduino? That was perfect for your project.My logic is basically this:
If I'm < 2 or > 15 feet away it will stop the cart, if I'm between 10 and 15 feet it will set a "crawl" speed until I catch up.
- The LidarD tracks my distance to the cart and sends a HTTP/PUT request to the ThrottleD to adjust the speed.
- Using a remote control I can adjust the speed up/down or directly to 1 of the 5 possible speeds. I can also send a code to toggle an "ignore" flag in the ThrottleD so that it ignores speed changes from the LidarD.
With the software solution I can easily try alternative approaches to controlling the cart.
Like OpenCV and a camera on the RPi I could use hand signals instead of sending IR codes.
Or, since the keeping the video focused was an issue for me I thought of trying voice commands. "Hey cart slow down".
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