I’m happy to write my first post here. The reason is because I’d love to hear your suggestions and recommendations for the motor configuration I need for my project. Let me first do a brief summary of this project.
This project is encompassed within the context of my PhD: I am doing research in the field of aerial manipulation, i.e. a multirotor with a robot arm attached to it. More precisely, I am in the field of optimal control & trajectory generation: solving the problem of what torque do my motors must apply so robots perform a desired trajectory.
So far, all robots existing for that aim consider arms with Dynamixel-type motors. The problem with this kind of motors is that you cannot torque-control them. And this is why I came up with ODrive and BLDC.
I am gonna do a list of important issues to have in mind when selecting the motors:
- Light-weight is crucial. The whole 2DOF manipulator cannot exceed 500g of mass. So I was thinking of a motors weighting max. 100g each.
- The links length is gonna be small. I am thinking of 100mm each. Since it is for research purposes the max. force done by the end-effector is not that important. I’d say that it could lift 100g in the worse-case configuration. That means a torque in the first joint of 0,2Nm aprox.
- I expect to add a reduction belt system for each motor of 1:5.
- The motor for the second joint is gonna be placed also in the base so the first one does-not have to lift also the weight of the second motor.
- The motors will be most of the time stalling.
- Since my motors will be most of the time stalling, is it better to consider gimbal motors instead of typical BLDC?
- I’d would need absolute position of my motors during all experiments. In case of adding absolute encoders, will I have do some sort of “homing” sequence when starting up?
- I was thinking of powering the manipulator up with 4S battery (14.8V nominal voltage), is that ok?
As I said before, I’d love to hear you recommendations for the motors. I was thinking in the Tarot 4008 motors.
I think this is all I wanted to explain. In case you don’t have enough information or you need a more advanced design, I’ll go back with updated info.
Thank you very much,