System and method for vehicle axle load measurement with hysteresis compensation and acceleration filter
First Claim
1. An axle load sensing system for a vehicle having an air bladder support system mounted between the frame of the vehicle and an axle, the axle load sensing system comprising:
- at least a first pressure sensor providing air pressure readings for at least one air bladder of the air bladder support system;
first and second transfer functions relating air pressure in the air bladder to weight carried by the air bladder support system;
a transfer function indication responsive to a direction of change in air pressure in the air bladder for indicating which of the first and second transfer functions to interrogate to determine axle load; and
a processor connected to receive the air pressure readings and responsive to the transfer function indication for interrogation of one of the first and second transfer functions using the air pressure readings as an input to return an estimate of load carried by the air bladder support system.
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Accused Products
Abstract
Vehicle on-board measurement of axle load and gross combined vehicle weight is improved for an air bladder suspended vehicle by allowing for suspension hysteresis. Suspension hysteresis results in at least two distinct air pressures being possible in an air bladder for a single load. The system also reduces the disruptive effect of vehicle acceleration and deceleration on load determination. Vehicle drive train management is enhanced using the load information to effect transmission gear selection.
28 Citations
23 Claims
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1. An axle load sensing system for a vehicle having an air bladder support system mounted between the frame of the vehicle and an axle, the axle load sensing system comprising:
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at least a first pressure sensor providing air pressure readings for at least one air bladder of the air bladder support system;
first and second transfer functions relating air pressure in the air bladder to weight carried by the air bladder support system;
a transfer function indication responsive to a direction of change in air pressure in the air bladder for indicating which of the first and second transfer functions to interrogate to determine axle load; and
a processor connected to receive the air pressure readings and responsive to the transfer function indication for interrogation of one of the first and second transfer functions using the air pressure readings as an input to return an estimate of load carried by the air bladder support system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A vehicle comprising:
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a tractor having a steering axle and at least a first drive axle;
a front suspension supporting the tractor from the steering axle and a rear suspension supporting the tractor from the first drive axle, the front suspension and the rear suspension each including at least one air bladder as a primary load bearing element;
air pressure sensors coupled to the air bladders for providing pressure readings;
a controller area network installed on the vehicle including a bus, an auxiliary controller connected to the bus for receiving air pressure sensor readings and an electronic system controller connected to the bus for communication with the auxiliary controller, the electronic system controller having a load determining program taking the air pressure sensor readings as inputs for determining loads on the steering axle and the first drive axle;
a plurality of transfer functions relating air pressure sensor readings to loads on each air bladder, including a first transfer function operative if load last increased and a second transfer function operative if load last decreased; and
the transfer functions returning load estimates upon interrogation by the electronic system controller executing the load determining program using pressure readings as inputs. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification