I want to start with my first robot project and need some help ordering the electronics.
I want to make a 4x4 (off road) robot with in the future pneumatic ride height control . But I first want to start on the “simple” way bij building a LEGO frame with 4 or more wheel on it with normal lego suspenion. I do not want to have a tank style way of steering but I want to make the normal steering methode that car’s uses.
So…
I think i need the following to do this (please advise when I am wrong)
1x 12V battery pack (for 12V motors)
1x 6V battery pack (for bot board, sensors, servos) Or sould i use a 6 volt regulator?
1x Battery pack charger. I need a 230V because I live in the Netherlands
1x Bot board 2
1x BASIC Atm Pro 28 pin (what is the difference between normal and Pro?)
4x Gear head motor 12vdc 200rpm with external motor shaft (in the future i what to check the actual rpm of the motor
2x motor controller. Type unknown need to control each motor separate.
2x Servo motor for sheering the front and rear axle
3x sharp IR sensor
And i should also order the cabels to connect everything.
Could you please give me any advice what i should or should not do.
Thanks for the info, I do not know if I will use the Ackerman Steering principle because I do not know if I can build that with technical Lego.
I want to do that in the future, but first i will focus on one pair. I a school project I have worked on a biped and we used digital servo’s because they where better in holding there position. I think i have to use the same for the steering.
Generally speaking digital servos will provide better performance in both torque and position resolution because of the rate the motor power and position are adjusted internal to the servo. In a biped this has many benefits with regard to strength and stability as most of the weight is actively carried by the servos all the time. In a vehicle the weight is typically carried by a mechanical linkage or bearing so there may be less torque requirements. Position resolution however may be more important as small amounts of error in steering accumulate or translate into large positional error of the vehicle over time.
Here is an interesting paper you may have already found with a lot of lego building techniques and information relating to drive train and steering design. I don’t know that it is conclusinve about anything in particular but it makes interesting reading on the topic in general.
I think probably one of the first challenges mechanically will be to find a way to get power to the wheels being steered. You may be able to replicate the front linkages used in 4wd r/c trucks or rock crawlers using lego parts. Once you figure out how to make independent steerable powered wheels then implementing the ackerman principles should become mostly about software.
. But I first want to start on the “simple” way bij building a LEGO frame with 4 or more wheel on it with normal lego suspenion. I do not want to have a tank style way of steering but I want to make the normal steering methode that car’s uses.
