BECKHOFF AL2000 Application - Manual (Page 29)

Eiserstraße 5 / D-33415 Verl / Telefon 05246/963-0 / Telefax 05246/963-149
29
Step 3: Force analysis
Sketch a motorforce-time diagram. The motorforce depends on:
• Required accelation and deceleration forces.
• Friction forces.
• Processing contact forces (for instance when using bits or cutters).
• For vertical applications: the gravitational forces
The maximum force F
max
is the overall maximum force, driving or braking. The motor’s peak force should meet
this. Consider the square time average force F
rms
. This force should remain below the motor’s continuous force.
Case force analysis: motorforce versus time diagram:
In the case we get the following results.
Parameter
Acceleration
phase (t
a
)
Maximum velocity
phase (t
c
)
Deceleration phase
(t
d
)
Settling and gripper action
phase
Dt(s) 0,1 0,167 0,1 0,5
a(m/s²) 30 0 -30 0
F
a,c,d
(N) 600 0 -600 0
F
f
(N) 30 30 30 0
F
tot
(N) 630 30 -570 0
The mean force during the cycle: