Hi,
i am starting the design of a quite specific robot and needs some help.
It would be used for a dance show where performers have some videos projected on their body, and not in the background. I am visual artist for shows and used to work with real time video softwares. So no problem about the visual part of the project. I also used to code onto arduino or atmel microcontrollers.
I need some help for the robot hardware design.
If somebody can give me some advices, it should be very nice !
The robot is a simple chassis, onto which is hanged a 4500 lumens videoprojector. The weight is 3,5kg.
There is also a macmini (realtime video is done on os x) and a camera.
The total payload is approximately 6 kg (13 lbs) without robot parts.
The videoprojector bottom part of the optic is really near the floor, less than one cm.
The chassis size is approximately 50cm*50cm. and total height must not be more than 10cm.
The speed ideal would be from 1 mm/s to 1 meter/s but i imagine it is not so easy. So the most important would be to be really precise at low speed. So if the robot can drive from 1mm to 5cm or 10cm/s, it would be really nice. And rotate very slowly…
And acceleration must be quite slow, to have smooth motion, not sudden at all.
Like the robot must rotate and translate at the same time, i should choose the omniwheel solution.
I would prefer use a 3 motored omniwheels, but if it is better four…
About the contextual floor : a stage floor is perfectly flat, and quite always at 0° pitch. It has dance flooring so a plastic flat mat, it is not particulously slippy, a little bit like linoleum.
It is difficult for me without a lot of experience, to choose the rights parts, i mean, particulously the motor power, i don’t have any experience about the omniwheel efficiency.
another question :
is the gyroscope totally important on a flat clean floor, or are the omniwheels motors quite easy to calibrate to have a quite good quality translation without it.
another question :
there is the question of power, like it is impossible to have the videoprojector wireless powered (too much batteries and weight…), i would have a power cable (1,5mm2 and round style, not flat).
If a omniwheeled robot is translating and if we apply a really light resistance to it (simulating the weight/resistance of the cable disposed on the stage floor), do the robot will be influenced by this?
Actually i imagine getting :
- 3 or 4 cc motor with encoders
- the omniwheels that can resist to a such payload (6kg / 3 or 4 ?? + a safe 100%more ?)
- the corresponding gearbox to attain a so slow speed (1mm/s to 5cm/s)
- a 4 channels (or singles) motor drivers with speed control (in pwm for example).
i used the robotshop design tools to have an idea of where i go, but the calculated values appears to me really low, not even 1A…
i don’t know if better to choose 6cm wheels or 10cm…
I can’t plan actually where there will be some bad surprises so,
any advices is welcome ! and sorry for my english not perfect at all.
Thank you !
Pierre