What should be the position of the arm when power is off and disconnected.
My AL5D “arm” section lowers to the ground under the weight of the “wrist/gripper” section.
I carried out correctly the checking of the arm stiffness as per the assembly instructions, but
this was obviously without the added weight of the wrist assembly.
The springs do help, but not enough for the “arm” section to remain horizontal in its parked “on power”
position.
As such, on using the Sequencer Utility, turning the power on and activating the arm and shoulder servos, the
arm and shoulder jerk rapidly into their default parked positions. I would prefer if they performed this action
far more smoothly and slowly !
The default position of the arm when powered off will be dictated by the last powered position, the stiffness/resistance of the assembly and gravity. If the arm is extended when it is powered off, it will very probably fall down to the surface underneath when powered off. All of the joints should move freely with little resistance when not powered.
The springs mounted at the back are meant to reduce the power requirements from the servo motors when the arm is outstretched. They are not enough to hold it up in most cases when no power is applied.
We recommend that you setup a custom pattern for sending the arm into a rest position very slowly instead, for example over 10 seconds. Attached to this post is an example pattern doing that with a screenshot on how to add it to the sequencer. Make sure that all the servo motor channels required are active. Also, it may need some tweaking for your specific arm since it may be calibrated differently.
Thank you, scharette, that was just the info I needed!
And thanks for the Rest pattern, it works very well. I used it in the AL5 ARM project of FlowBotics Studio (not in the standalone Servo Sequencer Utility)
I just have to remember to always return the arm to this Rest position before switching the power off.
