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- Nachgewiesen in: USPTO Patent Applications
- Sprachen: English
- Document Number: 20160288831
- Publication Date: October 6, 2016
- Appl. No: 15/038173
- Application Filed: December 06, 2013
- Claim: 1. A method for determining whether a vehicle steering torque exceeds a predetermined maximum steering torque limit in advance while a vehicle is being controlled by a lane keeping system, said method comprising: obtaining lane information concerning a lane that the vehicle is traveling in at a predetermined number of sample times in the future; generating a desired path for the vehicle to maintain the vehicle in the lane; obtaining vehicle motion information required to maintain the vehicle on the desired path at each of the sample times; determining steering angles for the vehicle that are necessary for the vehicle to track the desired path at each of the sample times based on the desired path and the vehicle motion information; determining the vehicle steering torque required to steer the vehicle for each of the steering angles; determining whether any of the steering torques exceeds the predetermine maximum torque limit; and issuing an alert if any of the steering torques does exceed the predetermined maximum torque limit prior to the lane keeping system being required to command that torque to steer the vehicle.
- Claim: 2. The method according to claim 1 wherein generating a desired path includes using a polynomial equation.
- Claim: 3. The method according to claim 2 wherein the polynomial equation is: [mathematical expression included] [mathematical expression included] [mathematical expression included] where x is the longitudinal distance from the vehicle center, y is the lateral distance from the vehicle center, vx is the vehicle longitudinal speed, L is the lane width, ΔT is the time of the path generation distance, and a are coefficients.
- Claim: 4. The method according to claim 1 wherein obtaining vehicle motion information includes obtaining vehicle longitudinal speed v, vehicle lateral speed vy, vehicle yaw rate w, vehicle lateral acceleration ay and vehicle yaw acceleration {dot over (w)}.
- Claim: 5. The method according to claim 4 wherein obtaining vehicle motion information can be directly determined from desired path parameters and using the equations: vy={dot over (y)}−vxφ {dot over (y)}≡dy/dt=y′vx y′=5a5x4+4a4x3+3a3x2+2a2x+a1 ay≡ÿ=d2y/dt2=y″vx2+y′ax y″=20a5x3+12a4x2+6a3x+2a2 w=y′ {dot over (w)}=d(y′)/dt=y″vx.
- Claim: 6. The method according to claim 1 wherein determining steering angles for the vehicle includes using the equation: [mathematical expression included] where vy is the vehicle lateral speed, vx is the vehicle longitudinal speed, w is the vehicle yaw rate, m is vehicle mass, δ is vehicle steering angle, I is vehicle inertia, Cf is front cornering stiffness, Cr is rear cornering stiffness, and a is the distance from the vehicle center to a front axle, and b is the distance from the vehicle center to a rear axle.
- Claim: 7. The method according to claim 1 wherein determining the vehicle steering torque includes using the equation: [mathematical expression included] where τtotal is total torque and includes a self-aligning torque, driver initiated torque and steering system torque, δ is the vehicle steering angle, z is a variable representing system delay for a response of the steering system, D is a pure time delay as the number of sample time steps, c and d are steering system parameters, and n and m are system orders.
- Claim: 8. The method according to claim 7 wherein the variables c and d are solved using a least-square method.
- Claim: 9. The method according to claim 1 wherein generating a desired path includes generating a vehicle lateral distance and a vehicle heading angle.
- Claim: 10. A method for determining whether a vehicle steering torque exceeds a predetermined maximum steering torque limit while a vehicle is being controlled by a lane keeping system, said method comprising: obtaining lane information concerning a lane that the vehicle is traveling in at a predetermined number of sample times in the future; generating a desired path for the vehicle to maintain the vehicle in the lane including determining vehicle lateral distance and vehicle heading angle at each sample time; obtaining vehicle motion information required to maintain the vehicle on the desired path at each of the sample times including obtaining vehicle longitudinal speed, vehicle lateral speed, vehicle yaw rate, vehicle lateral acceleration and vehicle yaw acceleration; determining steering angle for the vehicle that are necessary for the vehicle to track the desired path at each of the sample times based on the desired path and the vehicle motion information; determining the vehicle steering torque required to steer the vehicle for each of the steering angles; determining whether any of the steering torques exceeds the predetermined maximum torque limit; and issuing an alert if any of the steering torques does exceed the predetermined maximum torque limit prior to the lane keeping system being required to command that torque to steer the vehicle.
- Claim: 11. The method according to claim 10 wherein determining steering angles for the vehicle includes using the equation: [mathematical expression included] where vy is the vehicle lateral speed, vx is the vehicle longitudinal speed, w is the vehicle yaw rate, m is vehicle mass, δ is vehicle steering angle, I is vehicle inertia, Cf is front cornering stiffness, Cr is rear cornering stiffness, and a is the distance from the vehicle center to a front axle, and b is the distance from the vehicle center to a rear axle.
- Claim: 12. The method according to claim 10 wherein determining the vehicle steering torque includes using the equation: [mathematical expression included] where τtotal is total torque and includes a self-aligning torque, driver initiated torque and steering system torque, δ is the vehicle steering angle, z is a variable representing system delay for a response of the steering system, D is a pure time delay as the number of sample time steps, c and d are steering system parameters, and n and m are system orders.
- Claim: 13. The method according to claim 12 wherein the variables c and d are solved using a least-square method.
- Claim: 14. An alert system for determining whether a vehicle steering torque exceeds a predetermined maximum steering torque limit while a vehicle is being controlled by lane keeping system, said alert system comprising: means for obtaining lane information concerning a lane that the vehicle is traveling in at a predetermined number of sample times in the future; means for determining a desired path for the vehicle to maintain the vehicle in the lane; means for obtaining vehicle motion information required to maintain the vehicle on a desired path at each of the sample times; means for determining steering angles for the vehicle that are necessary for the vehicle to track the desired path at each of the sample times based on the desired path and the vehicle motion information; means for determining the vehicle steering torque required to steer the vehicle for each of the steering angles; means for determining whether any of the steering torques exceeds the predetermined maximum torque limit; and means for issuing an alert if any of the steering torques does exceed the predetermined maximum torque limit prior to the lane keeping system being required to command that torque to steer the vehicle.
- Claim: 15. The alert system according to claim 14 wherein the means for generating a desired path uses a polynomial equation.
- Claim: 16. The alert system according to claim 15 wherein the polynomial equation is: [mathematical expression included] [mathematical expression included] [mathematical expression included] where x is the longitudinal distance from the vehicle center, y is the lateral distance from the vehicle center, vx is the vehicle longitudinal speed, L is the lane width, ΔT is the time of the path generation distance, and a are coefficients.
- Claim: 17. The alert system according to claim 14 wherein the means for obtaining vehicle motion information obtains vehicle longitudinal speed v, vehicle lateral speed vy, vehicle yaw rate w, vehicle lateral acceleration ay and vehicle yaw acceleration {dot over (w)}.
- Claim: 18. The alert system according to claim 14 wherein the means for determining steering angles for the vehicle uses the equation: [mathematical expression included] where vy is the vehicle lateral speed, vx is the vehicle longitudinal speed, w is the vehicle yaw rate, m is vehicle mass, δ is vehicle steering angle, I is vehicle inertia, Cf is front cornering stiffness, Cr is rear cornering stiffness, and a is the distance from the vehicle center to a front axle, and b is the distance from the vehicle center to a rear axle.
- Claim: 19. The alert system according to claim 14 wherein the means for determining the vehicle steering torque uses the equation: [mathematical expression included] where τtotal is total torque and includes a self-aligning torque, driver initiated torque and steering system torque, δ is the vehicle steering angle, z is a variable representing system delay for a response of the steering system, D is a pure time delay as the number of sample time steps, c and d are steering system parameters, and n and m are system orders.
- Claim: 20. The alert system according to claim 19 wherein the variables c and d are solved using a least-square method.
- Current International Class: 62; 62
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