Variable displacement pump with back-up

A system comprising:

• a variable displacement pump (VDP) with a pump inlet and a pump outlet, wherein the VDP is configured to receive a flow at the pump inlet at a first pressure and to discharge a flow from the pump outlet at a second pressure elevated relative to the first pressure, wherein the VDP includes a variable displacement mechanism configured to vary the second pressure;
• a second pump in fluid communication to receive flow at the pump inlet at the first pressure and to discharge flow from an auxiliary outlet;
• a backup selector in fluid communication with the pump outlet and with the auxiliary outlet, wherein the backup selector is configured to operate in a normal mode to supply the pump outlet from the VDP and to supply the auxiliary outlet from the second pump, and wherein the backup selector is configured to switch to a backup mode to supply the pump outlet from the second pump upon failure of the VDP;
• a pressure sensor operatively connected to the pump outlet to generate feedback indicative of the second pressure;
• a controller operatively connected to the pressure sensor and to the variable displacement mechanism for control of the VDP;
• an output splitter configured to split flow from the pump outlet to a first outlet branch and to a second outlet branch for supplying two different systems each having a different pressure schedule, wherein the output splitter is operatively connected to the controller, which is configured to control the output splitter to regulate pressure in both of the first and second outlet branches;
• and
• an electrohydraulic servo valve (EHSV), wherein the EHSV includes a first connection to the pump inlet, a second connection to the pump outlet, and a pump control line operatively connected to actuate the variable displacement mechanism, wherein the controller is operatively connected to control the EHSV to actuate the variable displacement mechanism based on feedback from the pressure sensor, and wherein the variable displacement mechanism includes a position sensor configured to generate feedback indicative of position of the variable displacement mechanism, wherein the controller is operatively connected to the position sensor to control the EHSV based on feedback from the position sensor.