Suspension control system providing closed loop control of hydraulic fluid volumes for an agricultural machine
First Claim
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1. A suspension system for an agricultural machine, comprising:
- a plurality of suspension assemblies, each suspension assembly comprising a swing frame assembly and a cylinder, each cylinder comprising a piston rod configured to extend and retract with respect to a base, wherein the swing frame assembly is coupled to the agricultural machine, and wherein the cylinder is operationally coupled to the swing frame assembly at an actuation point;
a plurality of position sensors, each position sensor being configured to generate a signal indicating a suspension height;
a plurality of electronically controlled valves, each electronically controlled valve being configured to control a flow of fluid to and from a control volume for operating a cylinder;
a plurality of accumulators, each accumulator comprising a fluid portion moveable with respect to a gas portion, each accumulator being configured with respect to a cylinder, wherein each control volume for operating a cylinder includes a fluid portion of an accumulator;
a plurality of pressure sensors, each pressure sensor being configured to generate a signal indicating a pressure of a control volume; and
a processor in communication with the plurality of position sensors, the plurality of electronically controlled valves and the plurality of pressure sensors, the processor executing a program stored in a non-transient medium to;
determine a measured amount of fluid in each control volume using a position indicated by a position sensor configured with respect to a cylinder and a pressure indicated by a pressure sensor of a control volume for the cylinder;
calculate an error value for each control volume as a difference between a target amount of fluid for the control volume and the measured amount of fluid in the control volume; and
control the electronically controlled valves in a closed loop control system to flow fluid to or from the control volume to minimize the error value.
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Abstract
In one aspect, a control system is provided which determines fluid flow in a suspension system for an agricultural machine by determining total fluid in a closed loop piston system. Fluid is determined using position sensors and a pressure transducers and application of the ideal gas with respect to each accumulator. A closed loop control system can then target an amount of fluid for optimum suspension control.
41 Citations
20 Claims
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1. A suspension system for an agricultural machine, comprising:
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a plurality of suspension assemblies, each suspension assembly comprising a swing frame assembly and a cylinder, each cylinder comprising a piston rod configured to extend and retract with respect to a base, wherein the swing frame assembly is coupled to the agricultural machine, and wherein the cylinder is operationally coupled to the swing frame assembly at an actuation point; a plurality of position sensors, each position sensor being configured to generate a signal indicating a suspension height; a plurality of electronically controlled valves, each electronically controlled valve being configured to control a flow of fluid to and from a control volume for operating a cylinder; a plurality of accumulators, each accumulator comprising a fluid portion moveable with respect to a gas portion, each accumulator being configured with respect to a cylinder, wherein each control volume for operating a cylinder includes a fluid portion of an accumulator; a plurality of pressure sensors, each pressure sensor being configured to generate a signal indicating a pressure of a control volume; and a processor in communication with the plurality of position sensors, the plurality of electronically controlled valves and the plurality of pressure sensors, the processor executing a program stored in a non-transient medium to; determine a measured amount of fluid in each control volume using a position indicated by a position sensor configured with respect to a cylinder and a pressure indicated by a pressure sensor of a control volume for the cylinder; calculate an error value for each control volume as a difference between a target amount of fluid for the control volume and the measured amount of fluid in the control volume; and control the electronically controlled valves in a closed loop control system to flow fluid to or from the control volume to minimize the error value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An agricultural sprayer comprising:
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a chassis supported by front left, front right, back left and back right suspension assemblies, each suspension assembly comprising a swing frame assembly and a dual action hydraulic cylinder, each hydraulic cylinder comprising a piston rod configured to extend and retract with respect to a base, wherein the swing frame assembly is coupled to the sprayer at a pivot point and is coupled to a wheel at a hub point, and wherein the hydraulic cylinder is operationally coupled to the sprayer at a cylinder point and is also operationally coupled to the swing frame assembly at an actuation point distal from the pivot point such that action of the hydraulic cylinder at the actuation point causes the swing frame assembly to pivot at the pivot point; a plurality of tires, each tire being mounted to a wheel; a sprayer boom extending transversely relative to the chassis; a plurality of position sensors, each position sensor being configured to generate a signal indicating a suspension height; a plurality of electronically controlled valves, each electronically controlled valve being configured to control a flow of hydraulic fluid to and from a control volume for operating a hydraulic cylinder; a plurality of accumulators, each accumulator comprising a hydraulic fluid portion moveable with respect to a gas portion, each accumulator being configured with respect to a hydraulic cylinder, wherein each control volume for operating a hydraulic cylinder includes a hydraulic fluid portion of an accumulator; a plurality of pressure sensors, each pressure sensor being configured to generate a signal indicating a pressure of a control volume; and a processor in communication with the plurality of position sensors, the plurality of electronically controlled valves and the plurality of pressure sensors, the processor executing a program stored in a non-transient medium to; determine a measured amount of hydraulic fluid in each control volume using a position indicated by a position sensor configured with respect to a hydraulic cylinder and a pressure indicated by a pressure sensor of a control volume for the hydraulic cylinder; calculate an error value for each control volume as a difference between a target amount of hydraulic fluid for the control volume and the measured amount of hydraulic fluid in the control volume; and control the electronically controlled valves in a closed loop control system to flow hydraulic fluid to or from the control volume to minimize the error value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification