Viet: Day co phai cai motor controller em muon mua khong? O day gia re hon ($70): http://www.solutions-cubed.com/solutions%20cubed/MPID2003.htm Em check ky xem no co can them nhung linh kien kem theo hay khong (cables, interface board...). BTW, anh gui 1 so ideas ve emergency stop modes cua may dua ban anh, em nghien cuu xem (trong attached files) Ha
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E-stop procedure (electronics drive by wire interface) 1. Normal mode: a. computer controls basic stamps using serial interface b. Two basic stamps control H-bridges independently using I2c interface c. H-bridges drive motors independently using bipolar PWM 2. E-stop pause mode: a. computer detects e-stop pause through latch and sends usual shutdown commands to throttle servo and actuator controllers b. we're done 3. E-stop disable mode: a. Relay connected to E-stop cuts throttle (via removing power to throttle servo and letting natural spring action work, assuming that will be sufficient) or kills engine b. Basic stamps receive high on some pin telling them that there is an e-stop disable c. Basic stamps send control signals telling H-bridges to pull in actuators using I2c d. H-bridges drive motors in reverse (pull in) using PWM until e. Basic stamps detect limit and stop pulling, assuming actuators lock and have a way of indicating limit (easiest: limit switches on new actuators yet to come, next easiest: pots on actuators read some value corresponding to pulled back, but then you have to calibrate this and store in NVRAM on the stamps. Suggestion was to go through an initial phase of going through full swing to automatically ahve stamps detect min/max. (extra code on stamp and program) Another thought is to send the stamps the values from calibration at startup, and stamps store them in NVRAM. f. kill engine if not already done in (a) Advantage: uses existing basic stamps Disadvantage: needs a watchdog IC to reset stamp if no heartbeat to reduce chance of crashing causing a catastrophe Alternative to 3 3'. E-stop disable mode: a. Relay connected to E-stop cuts throttle or kills engine b. Alternative controller lies in wait for E-stop disable to occur. c. For each actuator, a normally open relay or a MUX sits between the controller and the H-bridge and is normally kept energized/enabled connecting the normal controller to the H-bridge. It selects between the normal controller and the alternative controller. The alternative controller is simply a controller with its setpoint permanently set to a full back position. While in normal operation, this controller can sense the pot position and determines continually what direction the motor should go to pull back. However, the normal controller is in control. So, this signal never makes it to the H-bridge. When e-stop occurs, the signal makes it to them. On e-stop, relay deenergizes/MUX selects and contacts the normally closed contacts and makes connection between the alternative controller which then pulls back enough to match the default set point and shuts down. d. kill engine if not already done in (a) Advantage: uses a relay to select between two controllers; less coding on the stamps Disadvantage: we do not know what happens when you cut an I2c signal midstream Needs a watchdog We have never read the same pot using two stamps before. No telling what happens. We may need a relay to switch over the pots as well, which adds complexity. Anoter alternative to 3 3''. E-stop disable mode: a. Relay connected to E-stop cuts throttle or kills engine b. For each actuator, a DPDT relay sits between H-bridge and actuator. Normally, this relay is energized and passes the PWM from the H-bridge to the actuator, pullin gand pushing it as needed. On Estop, relay selects an alternative source for the actuator, one that simply pulls the actuator back. For this, we must have a mechanism to prevent continually pulling back on the actuator for longer than a few seconds, long enough to pull al the way back. We may use a 556 timer to limit the duration of the pull-back signal. It would be configured in a one-shot mode and triggered by the optoisolated e-stop output on the DARPA e-stop unit and would need to trigger another relay for power. (We don't want to revert back to computer control after the hardware timer is up, just cut power to the actuator after pulling back.) c. kill engine if not already done in (a) Advantage: uses discrete components which are presumably less prone to crashing than embedded system Disadvantage: pulls back blindly (unless you wire in 1/4 of LM339 comparator to detect the voltage over the pot and use that as a rough setpoint sending a low to the relay once that is achieved.) I suggest either 3 or 3''