Configuring S-Curve Profiles Configuring S-Curve Profiles While there are many different motion profiles that can be characterized as "S-curves", in the V+ oper- ating system, an S-curve is a trajectory that has a trapezoidal acceleration profile, giving an S-shaped velo- city profile. The benefit of a trapezoidal acceleration profile is that the rate of change of acceleration (the "jerk") can be controlled. (By comparison, the magnitude of the jerk for a square-wave acceleration profile is always infin- ite.) For many mechanisms, controlling the jerk is significant because high jerk values can cause the mech- anical structure of the robot to vibrate.
Minimizing structural vibrations is especially important at the end of a motion, since such oscillations can adversely affect the settling time of the robot, which can affect the cycle time. However, for stiff, strong mechanisms, a square-wave profile may result in shorter cycle times. For a general trapezoidal profile, there are four acceleration values that can be specified, as shown in S- Curve (Trapezoidal Acceleration) Profile: the ramp up to maximum acceleration, the ramp down from max- imum acceleration, the ramp up to maximum deceleration, and the ramp down to zero acceleration.
In V+ each of these four acceleration values can be individually specified, and a set of the four values defines a specific acceleration "profile". S-Curve (Trapezoidal Acceleration) Profile The S-Curve Profile Configuration dialog box, shown in the figure below, is used to configure the four accel- eration values. To open the dialog box, on the Robot Editor menu, click Configure > S-Curve Profiles . ACE User's Guide, 3.6.x 18316-000 Rev A Page 246