Where do I put an emergency stop in the pds system?

[Bennyboy]

Hello,
For a school project we, 5 students car technology from Belgium, are using an ezgo txt golfcart with a pds 36v system. We are trying to make it drive autonomous with a gps. Now we would like to put an emergency stop in it. But it should only make it stop driving, so only the Electric motor should stop. The rest of our electronics and controllers should keep on working.
Now, whitch wire can i put the relay in to safely stop the electric motor? The motor has partnumber: 73445g02
I hope you can help us

[rib33024]

Before you connect or disconnect any wires/cables. Make sure to put the Tow/Run switch in Tow. Don't forget

I would replace the Tow/Run switch. With a remote control no/off switch. That would stop the cart from operating, with no damage to the cart electronics/controller. And would not interfere with your steering and brake and GPS controllers. There will be more answers to follow from members.

[cgtech]

Yes, and take power for your autonomous control circuit from the batteries separately from the "normal cart wiring". And, you could also interrupt the tach sensor circuit (motor speed sensor), which would command the cart to try to bring itself to a stop (only near stop is possible, not "zero speed").The cart can try to stop itself, like if you forgot to set the park brake when you stop on a slope. Try yourself stopping on a hill, then let off the brake to coast, it will beep at you & try to prevent itself from rolling. If that signal were interrupted while driving, it would apply strong motor braking to try to "shut down". This is not a "fool proof" plan to stop everything in the event of a "everything has gone wrong" situation, but it has merits because it will cause the cart to try to stop itself with motor braking. The "total kill" would be interrupt the main solenoid, no more forward propulsion, but that will allow the cart to roll freely until it came to rest on its own. This is risky business (as Mythbusters has proven on many occasions). These are quite serious safety concerns. Don't base your plans on my opinion alone. Read more, and read the posts that are sure to follow mine. Some will likely say "don't even try, not safe", some will offer other ways to do it. Read up, think about it, safety is in your hands!! Absolutely do not disable the reverse beeper, and if it does not work now, FIX IT, before you go one step further! It is your alert if it is in reverse, or if the controller is in "stop now" mode. (these things may not work as described if you "kill" tow/run switch, or interrupt solenoid). Golf carts don't have safety protocols to meet "autonomous operation" standards, safety from here on out is up to you. Killing "tow/run" switch "Should" stop everything. Interrupting tach signal "Should shut it down, with motor braking, even at full throttle". You must test each move yourself, carefully! And in small steps!

[Rickochet]

Safety first. You have a 1,000lb. cart capable of going 19 mph. People get killed in or by golf carts every year. I hope you will have someone in the driver's seat at all times to take over in case of a glitch. You might also consider changing the controller to one that can be programmed to limit the speed.

[Bennyboy]

hello, we have put a relay with 2 normal open contacts. the spool is controlled by the key switch, this gives our elektricity to the extra ifm controllers for CAN. The other contact takes over the normal key switch. in This wire we have put the emergency stop. Now, when the emergency stop is pushed, only the motor stops, and we can still control the rest (steering, braking and accelerating is all controlled by linear actuators (with CAN communication) They can be controlled by a joystick next to the driver, the screen to control the rest is in front of the driver.
thanks for the replys

[JohnnieB]

Put the "Kill" relay in the wire the gray wire between J1 Pin-1 and the F/R switch.

When you change the F/R switch while moving, the PDS controller applies max regen braking and beeps the beeper rapidly. I don't remember if it completely stops cart movement, or just slows to about 4 KPH, so you will have to try it to find out for sure.

Just removing the voltage from the Common terminal of the F/R rocker switch will leave the controller powered up, so if it comes to rest on an incline, the walkaway safety feature will use max regen braking to keep the cart from coasting downhill very fast.