Control Two motors exactly at the same time

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1

using v3.6 Odrive 56 volt
to control two BLDC motors
i want the both motors move at the same time
in closed loop control after giving the order ‘move_to_pos’ or ‘pos_setpoint’
axis0 is moving first then axis1 after it
i want them to start the movement at the same time and End the movement at the same time, even if that makes one of them move faster than the other, just to satisfy the condition of starting and ending the movement at the same time

2

Can you define “same time” a little better? Are they moving the same distance? Are they getting the same target? How closely do they have to match?

1 Like
3

Thanks for replying
Sorry for being late
I am very new to this so please excuse me for any lack of information.
Let’s say for a two link, 2degree of freedom robot leg
Using a motor for the first link movement and the second motor for the second lower leg part
So, using inverse Kinematics to transform a certain trajectory into angles for the motors to move. So
I want the two motors axis0 and axis1to start the movement at the same time and end at the same time so the end effector can reach its required position
So i need the motors to start move at the same moment
Then move with different Velocities, to reach their angle goals at the same exact moment.
Any help with the Odrive orders
Now am just starting to recognize Odrive and playing with the Odrive configuration following the Documentation website, but i think this is not provided there.

4

When I write the orders respectively
The first motor axis0 move then after alittle time, the second motor axis1 moves

When i used the order set_pos, it moves with the maximum speed under the Velocity limit

When using mov_to_pos, it moves slower,

I need the both motors start and end at the same exact time, that means move with different velocities,

Is this gonna be done with something called threading??

6

Coordinated motion the way you describe is not part of the ODrive firmware. You will need to use an external motion controller that generates trajectories and sends them at high speed to the ODrive using set_pos. Additionally, you’ll probably have to tune the PID controllers differently for each joint