How to easily define movements with multiple servomotors ?


I'm curently building a tretra/quadrapod or 4 legs spider robot using 8 servos.

I would like to define basic sequences (One step left, One step right, One step forward, one step backward, turn right, turn left) and to control each sequence for exemple by Bluetooth.

I already built a robotic arm (4 servos) or a biped robot (17servos). However :

  • for the robotic arm, i used a polulu servo maester board with a specific software
  • for the pibed robot, i used a specific board having also its specific software.

Each software can be used to define easily the position of each servo and to register each position to define a sequence that can be played in loop for example.

Today, i would like to draw the above mentioned sequences by using an arduino uno. Is there a method or a software that could help me to build each sequence easily (position and speed) ?

Have you watched videos of quadapods online? It is more of a wobbly bouncy shuffle than a step.

For this description, I will number the legs in clockwise order around the device, starting at the front right, as seen from above.
Whether you are walking forward/backward, the gate is broken into 4 phases.

  • Lift odd legs. Lower even legs. Wait for them to get there.
  • Move forward odd legs. Move backward even legs. Wait for them to get there.
  • Lift even legs. Lower odd legs. Wait for them to get there.
  • Move forward even legs. Move backward odd legs. Wait for them to get there.

For backward, swap forward and backward in that set.

To turn, swap the forward and backward on one side the the device.

Edit: do not use delay to wait for the servos to get to where they need to me. Read up on Robin's demo on Several Things at the Same Time.
You want to be able to interact with your bluetooth while waiting around.

Edit2: you also mentioned a side step. This is only doable if your walker's physical shape allows the front legs to swing 90 degrees to the front and the real legs to swing 90 degrees to the back. Then perform a walk step.