Hi there.
I need some advice and help to build a robot arm. The design is a 4 axis arm. Similar to
First I would advise You to make some drawings of how Your robot is supposed to look like and what mechanisms You want to implement in order for it to operate (something like SolidWorks works very well as a design tool).
While designing You should think about the size You want Your robot to be and materials it should be made of. This is very important because You have to find compromise between the sturdiness and lightness (ex.:
aluminium is sturdier than most
plastics are, however it is heavier, hence it will require more torque from servo motor). As Your robot is an arm it is designed to pick up various loads; You have to decide how heavy loads will be as that will impact Your decision of material You want to choose for parts. SolidWorks (or any other advanced enough CAD software) would help You to estimate weight and strength of parts; of course You can always calculate everything manually

Once You have Your dimensions and weights - it's time to look for suitable servo motors with high enough torque (total weight any given servo motor will have to lift =
payload +
robot arm itself (including other servos) +
15%*(payload + robot arm itself (including other servos)).
For the rotating wrist You can use
Servo Mod Tutorial.
I need some advice on the type of electronics i should use ?
As servos has driver module already intergrated inside, You do not need any specific hardware (such as H-Bridge) to make it work. More info on servos
here and
here. All You need is a microcontroller with PWM function (most, if not all, has it). Choice of microcontroller is totally up to You, choose the one which You feel most comfortable working with.
What program can be used ?
If by
program You mean programming software - then it all depends on the choice of uC (microcontroller), if You by
program You mean actual code that sits inside uC and drives it - then it also depends on uC of Your choice. Note that You will have to write controll software Yourself because it is not very likely that someone will have it for the exact robot as Yours.
can it be controlled RC radio transmitter ?
Yes it can. Actually, it would be easier to build RC robot than robot based on uC, however, I believe RC would be more expensive.
I hope all this somehow is helpfull.
Best regards,
NIR