Hello all
I want to make a robot car which will carry cinema-video equipment (cameras etc) of a total weight, lets say 5kg. The max speed will be 0.4 m/sec (40cm/sec) mainly constant but we need to controll this speed for 0% to 100% (100% = 0.4m/s) -if we need slower constant speed- propably with some Electornic Speed Controller (ESC). I say ESC becouse I m thinking to use brushless motor since we need extremely low noise . I will use tires with diameter 5cm , thus the radius is 2.5cm (or 0.025m). Only 1 motor. The robot car must be able to move at a declined surface of 20 degrees (no more). I can understand all the parameters of this great “Drive Motor Sizing Tool” except the “desired acceleration”. I don’t know what value to give in this tab. Battery will be 12V, for 100 min.
Please can you suggest me (for the specific project) what to put in “desired acceleration” ?
From what I can understand I will need a moter of about 150-160 rpm and about 7kg*cm torque or around 1A max current . So my second question is “which speed controler” to choose ? The speed control will be on the vehicle with a potentiometer !
any other info is welcomed
thank you all for your time
George
To confirm, are you looking to create your own custom platform, or prefer one which is essentially built / a kit?
Use the equation v2 = v1 + a*t
v1 = 0 (so it’s removed)
v2 = desired final velocity
t = time to get to that velocity
x2 = x1 +v1t + 1/2a*t^2
You can set x1 and v1 to 0 if the robot is at rest. Normally you don’t need anything too high, which is why we put the default value at 0.2m/s^2
robotshop.com/blog/en/drive- … -tool-9698
I would like to built my platform in order to understand how it works but since Imight have more projects it is possible to look for a ready built kit if needed.
Now my question is this. I need to built a robot car with 0.4 m/s max speed, load 5kg , low noise motor (1 motor) and control speed with a potentiometer over the vehicle. By using the “drive motor size tool” I end up to a DC motor of about 160 rpm, 7 kg-cm torque, around 1 A current and a battery of 12V.
1st question is : which motor to choose ? (brushless or sevo or other). low noise is essential
2nd question is : what kit (controller) to choose in order to control speed with a potentiometer on the vehicle ? (and why ?)
however if there is a similar ready kit please let me know !
thank you
Most smaller to medium sized robot platforms use brushed DC gear motors:
robotshop.com/en/gear-motors.html
Brushless, servo and stepper are rarely used.
However, given the low noise requirement, brushless geared will help, but our selection is quite limited, and the motor controller is different than for brushed.
This depends on the actuator you choose.
The estimate from the tool makes sense.
Ex: robotshop.com/en/banebots-p6 … RB-Ban-231
Plus: robotshop.com/en/banebots-rs … motor.html
This would give around 7Kg-cm, 12V…
Hello again.
This is a (i know bad) picture of a simplified idea (i have found in your site many of the other parts, on-off switches, relays etc). Since I would like less noise, so a brushless motor is more sutiable, can I use 2 motors (connected to the wheels this time, not like the picture) of this brushless motor ? -> robotshop.com/en/12v-159rpm- … motor.html
As i can see this motor is 12V 160 rpm, 2.4kg-cm. I believe that 2 x 2.4kg = 4.8kg cm is ok. I know I will need now 2 speed controllers (i can use the same potentiometer). But my great question is, what is the best way to controll speed ? what kit(s) i will need ? if we assume that this brushless motor is ok.
thank you.
picture :
s27.postimg.org/49ioucqz7/Drawing1_Model1.jpg
P.S. But in case if i use one of the 2 brushed motor you suggest me, i still wondering which electronic controller i need to control the speed.
RobotShop’s current selection of brushless geared motors is unfortunately limited, and we do not have any products to propose which would meet the specs.
You would need a brushless DC motor controller which accepts analog input.
