Slip control, Slip control example, Motec mdc 3 functionality – MoTeC MDC User Manual

Page 5

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MoTeC MDC

3

Functionality

The lock percentage for the constant lock mode is determined according to the following strategy:

Handbrake

ON

OFF

0%

Lock

% lock

ABS

ON

OFF

5%

Lock

Constant

lock %

The constant lock % is equivalent to the maximum lock achieved by the Mitsubishi factory AYC / ACD controller.

The lock percentage for the 0% lock mode is determined according to the following strategy:

% lock

ABS

ON

OFF

5%

Lock

0%

Lock

Note: ABS input functionality is turned off by default and normally not required.

Note: The handbrake status is ignored during a handbrake start from 0km/h – See Handbrake Override below.

For information on configuring the user modes see the MDC Manager section.

Slip Control

The slip control strategy detects slip (i.e.: rear speed ≠ front speed) and increases diff lock to maintain slip close to
the value specified in the Desired Slip table. The Desired Slip table specifies the value above which additional diff
lock will be applied, according to the slip control setup parameters.

The calculation of lock percentage for slip control is determined by the Slip Control Range and Max Slip Control
Lock parameters which apply to all user modes.

The following algorithm determines the %lock for slip control. The desired slip is the output from the Desired Slip
table.

IF Rear Speed > Front Speed

THEN Measured Slip = Rear Speed – Front Speed

ELSE Measured Slip = Front Speed – Rear Speed

Slip Control Factor = (Measured Slip – Desired Slip) / Slip Control Range

Constrain Slip Control Factor to the range 0 to 1

Slip Diff Lock = Slip Control Factor * Max Slip Control Lock

NOTE: Slip is specified as speed difference between front and rear wheels, not as a ratio of the speeds.

The addition of the calculated slip diff lock percentage is shown in the lock percentage strategy above.

Slip control example

Max slip control = 10% lock

Slip control range = 20 km/h

Desired slip (from Desired Slip table) = 10km/h

For a measured slip of 15km/h, slip diff lock = ((15 – 10) / 20) * 10 = 2.5%

For a measured slip of 30km/h or above, slip diff lock = 10%

For information on configuring the slip control parameters, see Setup | User Modes in the MDC Manager section.

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