Pedalless electronically controlled hydraulic braking system with redundant pump

Abstract

A braking system for an autonomous vehicle includes a brake device that is configured to brake a vehicle wheel. A first control system includes a first pump fluidly connected to the brake device via a hydraulic circuit. A second control system includes a second pump fluidly connected to the brake device via the hydraulic circuit. The second pump is fluidly connected in parallel with the first pump. A controller is in communication with the first and second control systems. The controller is configured to detect a fault in the first control system. The controller is configured to command the second pump to pressurize the hydraulic circuit in response to the failure.

What is claimed is: 
     
         1 . A method of controlling a brake system comprising the steps of:
 operating a brake circuit with a first control system to pressurize a brake circuit;   detecting a fault with the operating step relating to an undesired pressure in the brake circuit; and   activating a second control system to pressurize the brake circuit in response to the detected fault.   
     
     
         2 . The method according to  claim 1 , wherein the undesired pressure is a low pressure. 
     
     
         3 . The method according to  claim 1 , wherein the operating step includes driving a pump with a motor to pressurize the brake circuit, and the fault relates to at least one of the pump and the motor. 
     
     
         4 . The method according to  claim 3 , wherein the activating step includes activating a second pump in the second control system. 
     
     
         5 . The method according to  claim 1 , wherein the operating step includes commanding a pump with an electronic control unit, and the fault relates to the electronic control unit. 
     
     
         6 . The method according to  claim 5 , wherein the activating step includes activating a second electronic control unit. 
     
     
         7 . The method according to  claim 1 , wherein the activating step includes operating the second control system in combination with operational components of the first control system. 
     
     
         8 . The method according to  claim 7 , wherein the detecting step includes a controller determining which component of the first control system contains the fault. 
     
     
         9 . The method according to  claim 8 , wherein the activating step includes activating components of the second control system that correspond to the components of the first control system that contain the fault. 
     
     
         10 . The method according to  claim 1 , wherein the brake circuit has four brake devices each configured to respectively brake one of four vehicle wheels. 
     
     
         11 . The method according to  claim 1 , wherein the brake circuit is on an autonomous vehicle. 
     
     
         12 . The method according to  claim 1 , wherein the brake system does not have a manually operated brake pedal. 
     
     
         13 . A method of controlling a brake system comprising the steps of:
 operating a brake circuit with a first control system to pressurize a brake circuit;   detecting a fault with the operating step relating to an undesired pressure in the brake circuit; and   activating a second control system in combination with operational components of the first control system to pressurize the brake circuit in response to the detected fault.   
     
     
         14 . The method according to  claim 7 , wherein the detecting step includes a controller determining which component of the first control system contains the fault. 
     
     
         15 . A braking system for a vehicle, comprising:
 a first and second brake device respectively configured to brake a first and second vehicle wheel;   a first control system fluidly connected to the first and second brake devices;   a second control system fluidly connected to the first and second brake devices; and   a controller in communication with the first and second control systems, the controller configured to detect a fault in the first control system, and the controller configured to determine which component of the first control system contains the fault and to activate a corresponding component of the second control system in response to the detected fault such that the second control system operates in combination with operational components of the first control system.   
     
     
         16 . The braking system according to  claim 15 , wherein the first and second brake devices are fluidly connected via a first hydraulic circuit and a second hydraulic circuit. 
     
     
         17 . The braking system according to  claim 15 , wherein the first control system includes a first pump and a first motor coupled to the first pump. 
     
     
         18 . The braking system according to  claim 15 , wherein the second control system includes a second pump and a second motor coupled to the second pump. 
     
     
         19 . The braking system according to  claim 15 , wherein third and fourth brake devices are respectively configured to brake third and fourth vehicle wheels, and wherein the first, second, third, and fourth brake devices are all fluidly connected to the first and second control systems. 
     
     
         20 . The braking system according to  claim 15 , wherein the first and second vehicle wheels are wheels of an autonomous vehicle.