Hi!
I need some help with a project, we’re trying to turn an atv into a remote control.
What would be a way that I could use a dc motor like a servo? If I wired it into a servo controller would that work? Would I need to program a computer to translate inputs from a rc remote?
Looking to use a gm 12v electronic steering motor to run a chain connected to the drive shaft of a youth atv, the motor will need to be able to turn both clockwise and counter clockwise to a set distance for total wheel lockout; I’d like to connect it all to an rc controller, either a tqi or a dx3.
I have no clue where to even start with programming something, let alone to the level this project is requiring
I’ve been researching different methods to connect and control the motor, most of the applications done already are in full size vehicles so the equipment chosen is much larger than I’d like to use.
@Jnelligan Welcome to the RobotShop Community. Making an ATV remotely controlled is almost an dangerous as making a car remotely controlled in terms of potential harm and damage, so best to proceed step by step. If you’re not comfortable programming, you might consider just purchasing a decently powerful RC linear actuator for the steering and a relatively powerful RC servo for the throttle:
We used to offer linear actuators which could directly accept an RC signal, but those don’t seem to be available at this time. Consider a linear actuator with potentiometer feedback coupled to the LAC, which does accept RC input:
A bit of protection:
Help with mounting:
We strongly suggest a kill switch on the remote, and wiring a second remote control to a second kill switch in case something happens to the first remote. Always do a range test before driving and ensure there is nobody (including spectators or bystanders) in the area where you are driving (significant liability).
It’s also best to try to make it “dual control” so that you can have someone riding the ATV during tests who can take over at a moment’s notice, either quickly removing or disabling the RC control and having the ability to steer and/or apply the brakes.
I’ve been trying to find something besides linear actuators as it seems most of the ones I’ve found are fairly slow and would take approximately 2 seconds for total lockout.
I was talking to an electronic engineer and he had suggested using the circuit from a 12-24v hobby servo so I could plug it directly into the esc’s I already have.
For the kill switch I was thinking that being able to program in a function to pull battery power and lock the breaks if the receiver loses connectivity, that in line with a manual system should be plenty safe correct?
In the past, RobotShop had sold a DC to servo conversion kit which included the necessary electronics (DC motor controller with pre-programmed microcontroller which accepted RC input and potentiometer input), though it was discontinued. If you really want to convert a DC motor to “servo” (i.e. closed loop positioning):
DC motor controller which can handle the voltage and current
Microcontroller programmed to accept RC PWM signal and input from rotary potentiometer
A hobby servo motor’s motor controller likely won’t be able to provide sufficient current to a larger DC motor, and you might find issues with the potentiometer and gear ratio. Given that it would cost nothing, feel free to try.
I definitely want it to be safe, so may be more handle-able as a project to use that instead of dealing with the other aspects. I figured a potentiometer was was going to be necessary Over the steering column sprocket gear.
Do you have any suggestions for the implementation of kill switches? I’m thinking using another servo in line with the brakes so that it’s redundant, and wire that up to a separate receiver?
A “kill switch” needs to be as direct and as foolproof as possible. Cutting the battery’s power does not stop the ATV itself, so perhaps “dual” functionality of a separate actuator applying the brakes and cutting the engine? Just an opinion, but a servo might be more complex and as such, there is the possibility something goes wrong - the fewer mechanics, programming and electronics between a human and rendering teh ATV safe, the better.
For example, a powerful solenoid connected to a relay is pretty “direct” when it comes to motion (no gears, just magnets), connected to something that can activate it as reliably as possible from a distance. Many designers also ensure that loss of signal (by the receiver) also results in the vehicle stopping (i.e. out of range or something went wrong). You might try to integrate both - something which stays “disengaged” when there is a signal, and if the transmitter (operated by the human at a distance) stop transmitting, it engages, stopping the ATV.
An actuator uses less moving parts too correct? So reduce the possibility for that system to by damaged by over engineering it.
Steering is going to be the first big hurdle, after that’s all figured out then we will start adding the breaking system and kill switches, finishing on the throttle- that way was can guarantee that each portion is safe through testing.( we have a large plot of land we run our other rc’s at up to 115mph, so far from people or property)
“Actuator” is a more general term, but yes, a DC motor doesn’t contain many moving parts, but might require additional electronics. Yikes… don’t think I’ve ever traveled at 115mph in a wheeled vehicle (aside from an airplane during takeoff).
Well I can tell you even running an rc car at that speed is a little scary, if everything’s not set correctly they will take right off. Durable is something that would be nice since I am planning off-road use with it. I could probably increase the speed of the unit through using some additional leverage on a bar extended a number of inches from the steering column and connect it to the furthest point
@cbenson
I was wondering if these Torxis i01856 servos ( or any other power servo ) has an inbuilt slipclutch?
Steering without servosaver is a big risk (moneywise). Every bump or bounce can strip the gears.
I made a little napkin-sketch, how I’d integrate a slipclutch into the output-gear.
It’s not a final version. I still have to figure out, how to adjust clutch pressure without opening the servo.
Because the potmeter is always connected to the outputshaft, the servo won’t loose it’s position.
I was wondering if these Torxis i01856 servos ( or any other power servo ) has an inbuilt slipclutch?
None that I’m aware of unfortunately. VEX made a much smaller RC servo and offered an external “clutch” which broke under high load, but saved the servo.
I still have to figure out, how to adjust clutch pressure without opening the servo.
Because the potmeter is always connected to the output shaft, the servo won’t loose it’s position.
It’s design at this point - no right or wrong answer.
For sketching, try Sketchup (free) - you know how to create 3D views already and you might enjoy it.
