I've been thinking about how to make the arm training more accessable, would it be possible to add the following idea to the software?
A software toggle to enable training mode, this will start a record function.
Then while in training mode the holding torque is reduced, to just enough to hold the weight of the joints stactic, if the joint starts to move and sensed by the encoader, then more holding torque is applied, and the joint is returned to its inital point. (may not be required)
On the robot arm an external momentary button can be added, this is wired to one of the spare teensey inputs
While the momentry button is depressed, the steppers are allowed to skip steps, by the user manipulating the arm by hand, this is to move the arm to the desired posistion, the encoder steps are recorded.
The momentray button is released, and the holding torque is applied, at the new encoder posistion.
That movement line is added to the software, and the next line is waiting for the user to press the record button.
I'm not sure if I've made my thoughts clear enough, but hope it gives an idea of what could be done.
What if the software see's the new encoder position, by applying load or slip to the joint (while a "training mode" button is pressed) and increments the motor by that inducd slip value.
This will effectively manually jog the joint / arm.
Would that work?
Unfortunately I don't think this is possible for two reasons. The torque of the steppers with the specified drivers can't be controlled in software, it's set by the current setting with the physical dip switches on the drivers.
Secondly almost any amount of holding torque would make it very difficult to move the axes accurately espcially the J2 axis with it's 50:1 gearbox.
To implement this properly one would have to install strain gauges or some other kind of force sensor on each axis. Which is definitely doable but not without modifying the robot.
Feel free to correct me if I'm wrong though, would certainly be a useful feature. :)
The 3-5 could sort of be done with the E-stop though with some mild software trickery.