Virtual Spindle Length and Offset
Request Number: 80000350
Spindle Length and Spindle Offset both depend on the steer axis.
The kingpin axis or steer axis on an SLA or Macpherson strut suspension is defined by two points (the upper ball joint and the lower ball joint in the SLA suspension, the upper strut mount location and the lower ball joint in the case of the Macpherson strut suspension). When the kingpin axis is not defined by two distinct points, it must be calculated virtually, using the motion of the spindle to calculate the instant axis of rotation of the knuckle. The virtual requests (numbers 80000310-80000350) use this method to calculate the kingpin axis location, and parameters that rely on it. These requests should be used on suspensions that do not have a clearly defined steer axis, such as a 4 link or 5 link independent suspension.
For the computation of the kingpin axis, the steering needs to be free (no motion) and the suspension travel needs to be locked. The lock needs to be defined in the model and will be invoked, when computing the kingpin axis automatically. Defining the lock in the model involves the definition of an array, containing the position, direction and body to lock and calling a user subroutine to pass this information to the solver. See Locking Steering and Spring Travel for details.
.plt Files | .abf, .mrf Files | Component | Unit | Comment |
---|---|---|---|---|
F1 | RESULT(1) | Not Used | Not Used | Not Used |
F2 | RESULT(2) | Left Virtual Spindle Length | mm | The true left spindle length or the distance between the left wheel center and the point on the spindle which is closest to the virtual kingpin axis. |
F3 | RESULT(3) | Right Virtual Spindle Length | mm | The true right spindle length or the distance between the right wheel center and the point on the spindle which is closest to the virtual kingpin axis. |
F4 | RESULT(4) | Average Virtual Spindle Length | mm | The mean of the left and right virtual spindle length. |
F5 | RESULT(5) | Not Used | Not Used | Not Used |
F6 | RESULT(6) | Left Virtual Spindle Offset | mm | The true left spindle offset or the minimum distance between the left spindle axis and the left virtual kingpin axis. |
F7 | RESULT(7) | Right Virtual Spindle Offset | mm | The true right spindle offset or the minimum distance between the right spindle axis and the right virtual kingpin axis. |
F8 | RESULT(8) | Average Virtual Spindle Offset | mm | The mean of the left and right virtual spindle offset. |