Control Collateral

The controlCollateral function can only be used in one specific case: when a controller vault wants to invoke a function on a collateral vault on behalf of the account under its control. The typical use-case for this is a liquidation. The controller vault would detect that an account entered violation due to a price movement, and seize some collateral assets to repay the debt.

This is accomplished by the controller vault calling controlCollateral. It passes in the collateral vault as the target collateral and the violator as onBehalfOfAccount. The controller would construct a withdraw call using the its own address as the receiver. From the collateral vault's perspective, this appears as a regular withdrawal, and it does not need to know that the funds are being withdrawn due to a liquidation.