L6 Arm erratic moves question

Lynxmotion Robot Arms
1

Hello,

I just finished a L6 arm and have a question about jerkey movements.
My L6 will run a seq nice, completing the moves well, but if I re run the same seq the arm is erratic. If I keep running the same seq, the smoothness is different each time. I read here on the message board about power not being sufficient for the SSC-32 so I separated the power @ VL=VS jumper and attached a 9V battery to the VL. That helped smooth the operation alot. I am using the wall adapter for the servos only. When running a seq move, I am measuring power drops from 6.1V down to 5.3V (with an average of 5.5V for most of the seq run) at the VS1 terminal where the wall supply is connected. How much of a dip would be considered normal while VL is spplied from sep battery?

A second question:
In RIOS under the SSC32 config, at the bottom of the screen is a field for each servo labled “Rate”. What is this field for, and what are the ranges?

Thanks

2

Have you tried using the smoothing slider?

Are you using direct serial or a USB to serial cable?

I will ask Laurent to answer the second question.

3

Hello Vince,

the rate range is 0 to 255 :
0 = full speed, meaning as fast as the servo can move.
1 = slow to 255 = fast (but 0 should be faster than 255 anyway)

this feature is just here “for” this SSC-32 config form, for you to test with the sliders.

i have set it to “4” by default in order to avoid too fast move with sliders.

this feature has no effect elsewhere in the program.

4

I have my servo speed set to 6 and the arm moves smoothly.
Be careful when using the sliders, though. Manipulating robot arms at high-speed can very dangerous :smiley:

5

Yup! That’s why it says “Take it easy with the sliders”. :smiley:

6

Yes on the slider, I have run with the slider at both extremes.
On the serial, I initially started on my laptop (Toshiba) using a USB to Serial adpt by keyspan.
I then ran from my Dell desktop with a standard serial port and experienced basically the same behaviours.

any suggestions are appreciated…

7

Regarding the power readings, the dip seems to be worse than I thought.
I put a scope on the power term of the VS1 and can occasionally see dips as low as 4.8V. That may explain the controller resetting/rebooting. I am going to go look for a diff power source in my junk box :wink:

8

I think my problem has been solved. I replaced the wall adapter with a regulated DC power supply (dual outputs). Smooth as glass now.