On 18.05.16 08:30, Chris Albertson wrote: > This is a general problem that applies not just to CNC machines. What > to do if the human interface allows a human to tell a machine to do > something it can't do? In this case the interface allows you to > command the axis to move faster then it can. The best design is to > prevent this. You'd need to have some kind of force feedback, a > torque or brake applied to the command wheel to prevent you from > turning it to fast. Cheaper solution is a big red LED that lights up > as you approach 90% of the maximum speed. Or in place of the LED a > vibrator motor to shake the wheel.
I like the big red LED, especially together with a little mobile phone vibrator motor or a complaining squawker, but what about just limiting the joystick/knob output to MAX_VEL? Within LinuxCNC that ought to be possible, maybe using a hal limit component? If it had to be done in the arduino, then the limit would also not need to be hard-coded into the program if means to increase/decrease the value via the user interface were provided, as the result could then instead be saved in on-chip EEPROM. The latter method would permit scaling of the joystick travel to match MAX_VEL, whereas the former would result in the last bit of joystick travel doing nothing, which is suboptimal. If an operator is likely to jerk the joystick instantly to full travel, then it might be an idea to limit output to e.g. 95% of MAX_VEL, so that LinuxCNC can catch up despite limited MAX_ACCEL. Erik ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
