I would like to make a gripper that could squeeze +/- 5 lbs. What motors or designs would be best suited for that? I've been using small dc motors with pwm, but they lack power. Any ideas would be appreciated.Thanks-mike
By +/- 5 pounds, you mean nearly 5 lbs, not close and open 5 pounds in each direction?
A small gearmotor could drive a leadscrew mechanism to get up to 5 pounds. No need for pwm. Full power until a contact or limit switch activates and turns off.
Just squeeze around 5 lbs. or so when closing. Instead of a limit switch, is there a way with the prop to sense current level so it can respond when it gets too much load?
Perfect, thank you. It says in the description, good for robotic grip force. i missed that one. The propeller has 5v output, but the pins are in/out 3.3. In the sensor description 4.2 volts is equal to 25 lbs. I won't be near that range. Have you used this with the propeller without problems?
I'm a builder first. Sounds to me like your biggest challenge is getting a custom mechanism that can grip 5 pounds. Your particular choice of mechanism may lend itself better to one type of sensor, so IMO sorting out the mechanics first makes the most sense.
You could also make a gripper mechanism that simply stalls at 5 pounds, in which case a simple motor current sensor could work fine.
One of the nice features of Dynamixel servos is their torque sensing ability. You can both set the limiting torque amount to use and also read the current torque of the servo.
I doubt their AX-12A servos would be strong enough for your current application without some sort of additional mechanical advantage but their larger (and more expensive) servo can be bone crushingly strong.
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A small gearmotor could drive a leadscrew mechanism to get up to 5 pounds. No need for pwm. Full power until a contact or limit switch activates and turns off.
It is very flexible and can adapt quite well. It will take pressure up to 25 pounds.
You could also make a gripper mechanism that simply stalls at 5 pounds, in which case a simple motor current sensor could work fine.
I doubt their AX-12A servos would be strong enough for your current application without some sort of additional mechanical advantage but their larger (and more expensive) servo can be bone crushingly strong.
Here's a link to one of Crustcrawler's grippers.
No, I have only used them with a BS2 and BS2SX. If memory serves me correctly I believe there is an OBEX for that sensor.