Dear Friends,
We are working on the development of Industrial Robot.
We want to implement the collision detection feature in the robot.
Can any one guide us on how it can be done.
Thanks in advance
Sachin
Dear Friends,
We are working on the development of Industrial Robot.
We want to implement the collision detection feature in the robot.
Can any one guide us on how it can be done.
Thanks in advance
Sachin
That's... a very vague and open-ended question.
With industrial robots, generally the biggest problem is velocity and inertia -- by the time a collision can be detected, the damage has already been done. No robot can stop instantly, and the heavier the payload and the higher the velocity, the longer the deceleration ramp, even if the harshest possible stopping action is used. Robots intended for used alongside humans (Baxter, iiWA, etc) are either designed to be "soft", or operate with strict limits on the kinetic energy they can attain. They are also limited to very small payloads.
Collision methods that use non-contact sensing are complex and prone to false positives, and often suffer from maintenance issues in industrial environments.
Flexible tools, like the breakaway sensors often used on welding torches, only detect collisions between the torch and some obstacle, and are also limited to small payloads and/or low speeds.
Thanks SkyeFire for the response.
Actually we are at initial stage where we have kinematics, mechanical structure and motors.
I was wondering if i can monitor the motor current and gerenerate the stop signal if motor current exceeds defined limit.
This signal i can use for stoping the robot to avoid further damage.
I want to know if this is the right way or is there any other method to detect collision.
Regards
Sachin
It can be done, and has been done -- KUKA's built-in collision detection does this. But it doesn't change the inertia issue. It also requires "teaching" the collision detection system what the normal motor currents should be, for every motion in a robot path program, because the gravity and inertial factors cannot be modeled with sufficient accuracy. This also means that any change in robot speed can throw off the collision detection. The tolerance band must also be rather wide, since the motor current data is inherently noisy.
The bottom line is this: if you use motor current to detect a collision, you will not detect a collision until after it occurs and has applied substantial force (enough to raise the motor current above the tolerance threshold). Plus, if the robot is moving at high speed, by the time this detection takes place and the motion control system reacts, the robot has probably already "stalled" physically against whatever obstruction it hit.