# US 9,517,774 B2 · Static road gradient estimation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,774 B2 - Document ID: US9517774B2 - Status: Granted - Kind: B2 - Application number: 13/735,308 - Filed: 2013-01-07 - Published: 2014-03-06 - Granted: 2016-12-13 - Earliest claimed: 2012-08-31 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Hai Yu - Web page: https://patentgrep.com/patent/US9517774B2 ## CPC - B60W 40/076: Slope angle of the road - B60W 40/06: Road conditions - B60W 40/13: Load or weight - G06F 17/00: Digital computing or data processing equipment or methods, specially adapted for specific functions (information retrieval, database structures or file system structures therefor G06F16/00) - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A vehicle and a vehicle system are provided with a controller that is configured to generate output indicative of a static road gradient estimation based on a filtered longitudinal acceleration. The filtered longitudinal acceleration is dependent upon a derivative of a longitudinal acceleration. An initial value of the static road gradient estimation corresponds to at least one of a kinematic road gradient estimation and a dynamic road gradient estimation. ## Claims ### Claim 1 A vehicle comprising: an engine configured for automatic shutdown and restart; a controller configured to filter a longitudinal acceleration using a low pass filter having a bandwidth selected from a plurality of bandwidths based on a derivative of the longitudinal acceleration, generate output indicative of a static road gradient estimation based on the filtered longitudinal acceleration, wherein the controller is further configured to shutdown and restart the engine based on the static road gradient estimation; wherein an initial value of the static road gradient estimation corresponds to at least one of a kinematic road gradient estimation and a dynamic road gradient estimation. ### Claim 2 (depends on 1) The vehicle of claim 1 further comprising: an inertial sensor for providing a signal indicative of the longitudinal acceleration; wherein the derivative comprises a first order derivative of the longitudinal acceleration corresponding to a longitudinal jerk, and wherein the controller is further configured to filter the longitudinal acceleration using a low pass filter having a narrow bandwidth when the longitudinal jerk is greater than a jerk threshold. ### Claim 3 (depends on 2) The vehicle of claim 2 wherein the controller is further configured to: filter the longitudinal acceleration using a low pass filter having a wide bandwidth when the longitudinal jerk is less than the jerk threshold. ### Claim 4 (depends on 1) The vehicle of claim 1 wherein the derivative comprises a second order derivative of the longitudinal acceleration. ### Claim 5 (depends on 1) The vehicle of claim 1 wherein each road gradient estimation corresponds to an estimation quality factor; wherein the initial value of the static road gradient estimation corresponds to the kinematic road gradient estimation when a kinematic quality factor is greater than a dynamic quality factor; wherein the initial value of the static road gradient estimation corresponds to the dynamic road gradient estimation when the dynamic quality factor is greater than the kinematic quality factor. ### Claim 6 (depends on 5) The vehicle of claim 5 wherein the initial value of the static road gradient estimation corresponds to a default value when the kinematic quality factor and the dynamic quality factor are each less than a threshold quality value. ### Claim 7 (depends on 1) The vehicle of claim 1 wherein the controller is further configured to: generate output indicative of a static quality factor based on the derivative of the longitudinal acceleration. ### Claim 8 (depends on 1) The vehicle of claim 1 wherein the controller is further configured to: generate output indicative of a static quality factor based on a comparison of the derivative of the longitudinal acceleration to a first threshold and a second threshold, wherein the second threshold is greater than the first threshold. ### Claim 9 (depends on 8) The vehicle of claim 8 wherein the controller is further configured to: generate output indicative of a static quality factor corresponding to high quality, when the derivative of the longitudinal acceleration is less than the first threshold for longer than a time threshold; and generate output indicative of a static quality factor corresponding to intermediate quality, when the derivative of the longitudinal acceleration is greater than the first threshold and less than the second threshold. ### Claim 10 (depends on 8) The vehicle of claim 8 wherein the controller is further configured to: generate output indicative of a static quality factor corresponding to low quality, when the derivative of the longitudinal acceleration is greater than the second threshold. ### Claim 11 (depends on 1) The vehicle of claim 1 wherein the static road gradient is independent of a vehicle pitch angle. ### Claim 12 (depends on 1) The vehicle of claim 1 further comprising: a brake system for providing wheel torque; wherein the controller is further configured to adjust the wheel torque based on the static road gradient estimation. ### Claim 13 A vehicle system comprising: a controller configured to: filter a longitudinal acceleration using a low pass filter having a bandwidth selected from a plurality of bandwidths based on a derivative of the longitudinal acceleration corresponding to a longitudinal jerk, generate output indicative of a static road gradient estimation based on the filtered longitudinal acceleration, and generate output indicative of a static quality factor based on the longitudinal jerk. ### Claim 14 (depends on 13) The vehicle system of claim 13 wherein the controller is further configured to: generate output indicative of a static quality factor corresponding to full quality, when the longitudinal jerk is less than a stabilizing threshold for longer than a stabilizing time threshold. ### Claim 15 (depends on 13) The vehicle of claim 13 wherein the controller is further configured to: generate output indicative of a static quality factor corresponding to degraded quality, when the longitudinal jerk is less than a converging threshold and greater than a stabilizing threshold; wherein the converging threshold is greater than the stabilizing threshold; and generate output indicative of a static quality factor corresponding to non-qualified, when the longitudinal jerk is greater than the converging threshold. ### Claim 16 (depends on 13) The vehicle system of claim 13 wherein an initial value of the static road gradient estimation corresponds to at least one of a kinematic road gradient estimation and a dynamic road gradient estimation. ### Claim 17 A method for estimating a static road gradient comprising: filtering input indicative of a longitudinal acceleration using a low pass filter having a bandwidth selected from a plurality of bandwidths based on a derivative of the longitudinal acceleration; generating output indicative of a static road gradient estimation based on the filtered longitudinal acceleration; and generating output indicative of a static quality factor based on the derivative. ### Claim 18 (depends on 17) The method of claim 17 further comprising: providing an initial static road gradient estimation corresponding to at least one of a kinematic road gradient estimation and a dynamic road gradient estimation. ### Claim 19 (depends on 17) The method of claim 17 further comprising: controlling shutdown of an engine based on the static road gradient estimation.