Distributed hierarchical control system for a tandem axle drive system

A hierarchical control system for a tandem axle assembly for a vehicle, comprising:

• a vehicle level controller in communication with at least one of a power source and a transmission of the vehicle;
• an actuator in driving engagement with a portion of the tandem axle assembly;
• a shift controller in communication with the vehicle level controller and the actuator, the shift controller capable of placing the tandem axle assembly in at least a first operating condition and a second operating condition using the actuator, the shift controller including:
• a vehicle supervisor layer, the vehicle supervisor layer monitoring an operation of a dual range axle disconnect system forming a portion of the tandem axle assembly;
• a shift strategy layer, the shift strategy layer determining a modulated shift point of the dual range axle disconnect system;
• and
• an axle control layer, the axle control layer performing steps necessary to shift the dual range axle disconnect system;
• and
• a sensor in communication with the shift controller, the sensor communicating information about an operating condition of a portion of the tandem axle assembly, wherein the tandem axle assembly further includes a front axle and a rear axle, the dual range axle disconnect system is drivingly engaged with one of the front axle and the rear axle when the tandem axle assembly is placed in the first operating condition and the dual range axle disconnect system is drivingly engaged with both the front axle and the rear axle when the tandem axle assembly is placed in the second operating condition and in response to the sensor and an operating condition of at least one of the power source and the transmission of the vehicle, the shift controller adjusts a manner of placing the tandem axle assembly in at least one of the first operating condition and the second operating condition.

A method of shifting a tandem axle assembly for a vehicle using a hierarchical control system, comprising the steps of:

• providing the tandem axle assembly, the tandem axle assembly including a front axle, a rear axle, and a dual range axle disconnect system, the tandem axle assembly able to be placed in at least a first operating condition and a second operating condition;
• providing a power source and a transmission of the vehicle;
• providing the hierarchical control system, the hierarchical control system including:
• a vehicle level controller in communication with at least one of the power source and the transmission;
• an actuator in driving engagement with a portion of the tandem axle assembly;
• a shift controller in communication with the vehicle level controller and the actuator, the shift controller comprising a shift strategy layer, the shift controller capable of placing the tandem axle assembly in at least the first operating condition and the second operating condition using the actuator;
• and
• a sensor in communication with the shift controller;
• communicating information collected by the sensor about an operating condition of a portion of the tandem axle assembly to the shift controller;
• communicating information about an operating condition of at least one of the power source and the transmission of the vehicle;
• determing a modulated shift point of the dual range axle disconnected system with the shift strategy layer of the shift controller;
• and
• adjusting a manner of placing the tandem axle assembly in at least one of the first operating condition and the second operating condition in response to the information collected by the sensor.