1. The problem statement, all variables and given/known data Hello everyone I have got a cylindrical 6 axis force sensor (so I have the force Fx, Fy,Fz and torque Tx, Ty, Tz). Using these data I don’t know how I can find the point of force application. 2. Relevant equations 3. The attempt at a solution I try this The torque can be defined as the cross product I (Position vector) and F(force) Tx,y,z=Ix,y,z ^Fx,y,z So, I have 3 equations Tx=IyFz-IzFy Ty=IzFx-IxFz Tz=IxFy-IyFx But, when I solve the equation(in order to find Ix, Iy and Iz) , the variables in the equation vanish… Do you have an idea how find this point. Really thanks so much Alexandra :shy:
You can't expect it to give a specific vector for I. Suppose a solution is force G acting through the point r. Let s be any vector collinear with G. Then a force G acting through the point r+s is also a solution (indeed, the same solution really). One way to fix that is to add the equation I.F = 0
No, not in order to find a collinear vector; in order to find a perpendicular one. Consider a force F acting through some point in an object. You could shift the point of application to anywhere in that same straight line and it would be exactly the same. I.e. a force acts through a line rather than through any specific point of the line. That's why your original equations were not enough to pin down a point. Now, any I satisfying your equations would be a perfectly good answer. I merely proposed one way of selecting a specific point from that whole line of valid answers, namely, the point that made the I vector orthogonal to the F vector.