We are building the claw bot and are having intermittent servo issues with the gripper. They cut out and then start working again. Unplug the servo plug it in again they start working. Kinda sounds looks like the internal circuit breaker kicking out in the controller, but why?
P.S. We are using the old controllers and joysticks
The clawbot kit comes with four 393 motors, a motor is used to power the claw not a servo. If the claw motor is still being driven (a non zero control value sent to it) when closed the motor will stall and the current flowing through it will be high, after a few seconds the PTC (a thermal fuse) in either the motor or controller will trip and power to the motor will be lost. The PTC will only reset if the drive voltage is removed by sending a control value of zero or by physically disconnecting it.
The 393 motor powering the claw has more than enough strength to pickup a sack, however, control of the motor needs to be appropriate to allow this to happen.
I didn’t purchase the whole claw bot kit, I put together the parts for a claw bot myself, we are using some old 3 wire motors for the drive base and shoulder and a servo for the gripper. the 3 wire motors on the base and shoulder work great but still having that intermittent issue with the servo. How do we program it so we don’t have to keep the button pushed on the joystick to keep the gripper closed?
ROBOTC or EasyC? Which version? Did you say you were using the PIC?
Yes, it’s the PIC controller and Easy C V2
We replaced the servos with motors and they work great. But why did the servos return to the neutral position when not activated, and can it be fixed with programming?
Servo control is different to motor control. You send it a value in the range of -127 to +127 (or perhaps 0 to 255, I don’t use EasyC V2 so not sure exactly what it is) and the servo will go to that position and stay there. So, for example, to close the claw you might have to send it a value of 100, to open the claw perhaps a value of -50, you need to figure out what these numbers would be through testing.