Method of and apparatus for checking four-wheel steering characteristics of four-wheel-steered vehicle
First Claim
1. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising the steps of:
- changing the four-wheel steering characteristics according to a factor which can affect running of the vehicle by inputing a simulation signal representing said factor into a controller for determining the rear wheel angleturning the front wheels, measuring the actual turning angle of at least one of the front wheels and the actual turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheels and as determined by said controller on the basis of said simulation signal, thereby detecting the actual relation between the turning angles of the front and rear wheels, and checking whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by comparing the actual relation between the turning angles of the front and rear wheels with the preset four-wheel steering characteristics.
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Accused Products
Abstract
In order to check four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, the steering wheel is turned to turn the front wheels and the rear wheels, and the actual turning angle of the front wheels and the actual turning angle of the rear wheels are measured, thereby detecting the actual relation between the turning angles of the front and rear wheels. Whether the actual four-wheel steering characteristics of the vehicle deviates from the preset four-wheel steering characteristics is determined through comparison of the actual relation between the turning angles of the front and rear wheels with the preset four-wheel steering characteristics.
16 Citations
60 Claims
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1. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising the steps of:
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changing the four-wheel steering characteristics according to a factor which can affect running of the vehicle by inputing a simulation signal representing said factor into a controller for determining the rear wheel angle turning the front wheels, measuring the actual turning angle of at least one of the front wheels and the actual turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheels and as determined by said controller on the basis of said simulation signal, thereby detecting the actual relation between the turning angles of the front and rear wheels, and checking whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by comparing the actual relation between the turning angles of the front and rear wheels with the preset four-wheel steering characteristics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are tuned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising
steps of turning the front wheels, measuring the actual turning angle of at least one of the front wheels and the actual turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheels, thereby detecting the actual relation between the turning angles of the front and rear wheels, and checking whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics; - wherein said four-wheel steering system is arranged so that an insensitive zone in which the rear wheels are not turned even if the front wheels are turned is produced when the front wheel turning angle and the rear wheel turning angle are both substantially equal to 0, and in which the front wheels are turned left and right from the straight-ahead position, and the front wheel turning angle and the rear wheel turning angle at this time are measure, and whether the middle of the insensitive zone substantially coincides with the straight-ahead position of the front wheels is checked.
- View Dependent Claims (18, 19, 20)
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21. An apparatus for checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising
a front wheel turning angle measuring means for measuring the turning angle of at least one of the front wheels when the front wheels are turned, a rear wheel turning angle measuring means for measuring the turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheels, and a comparator means for detecting the actual relation between the turning angles of the front and rear wheels on the basis of data input from the front wheel turning angle measuring means and the rear wheel turning angle measuring means and determining whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics.
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41. An apparatus for checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system having a front wheel turning mechanism for turning the front wheels in response to operation of the steering wheel, a rear wheel turning mechanism for turning the rear wheels, a front wheel turning angle sensor for detecting the front wheel turning angle, a controller which receives a front wheel turning angle signal from the front wheel turning angle sensor and controls the rear wheel turning mechanism to turn the rear wheels in response to operation of the steering wheel according to preset four-wheel steering characteristics, said apparatus comprising
a simulation signal output means which is adapted to input a simulation front wheel turning angle signal representing a front wheel turning angle into the controller of the four-wheel steering system a rear wheel turning angle measuring means for measuring the turning angle of at least one of the rear wheels by which the rear wheel is actually turned under the control of the controller when said simulation front wheel turning angle is input into the controller, and a comparator means which detects the actual relation between the turning angles of the front and rear wheels on the basis of the simulation front wheel turning angle signal and data input from the rear wheel turning angle measuring means, and determines whether the actual four-wheel steering characteristics of the vehicle deviates from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics.
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55. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system having a front wheel turning mechanism for turning the front wheels in response to operation of the steering wheel, a rear wheel turning mechanism for turning the rear wheels, a front wheel turning angle sensor for detecting the front wheel turning angle, a controller which receives a front wheel turning angle signal from the front wheel turning angle sensor and controls the rear wheel turning mechanism to turn the rear wheels in response to operation of the steering wheel according to preset four-wheel steering characteristics, said method comprising
a step of inputting a simulation front wheel turning angle signal representing a front wheel turning angle into the controller of the four-wheel steering system a step of measuring the turning angle of at least one of the rear wheels by which the rear wheel is actually turned under the control of the controller when said simulation front wheel turning angle is input into the controller, and a step of detecting the actual relation between the turning angles of the front and rear wheels on the basis of the simulation front wheel turning angle signal and data input from the rear wheel turning angle measuring means, and determining whether the actual four-wheel steering characteristics of the vehicle deviates from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics.
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59. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising
steps of turning the front wheels, measuring the actual turning angle of at least one of the front wheels and the actual turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheel, thereby detecting the actual relation between the turning angles of the front and rear wheels, and checking whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics; - wherein the front wheels are turned left and right from the straight-ahead position while the front wheel turning angle and the rear wheel turning angle are measured, the change of the measured rear wheel turning angle with the change of the measured front wheel turning angle is graphed with the front wheel turning angle as the abscissa and the rear wheel turning angle as the ordinate, and whether the curve representing the change of the rear wheel turning angle with the change of the measured front wheel turning angle obtained when the front wheels are turned left and that obtained when the front wheels are turned right are symmetrical about the origin is checked.
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60. A method of checking four-wheel steering characteristics of a four-wheeled vehicle provided with a four-wheel steering system in which both the front wheels and the rear wheels are turned in response to operation of the steering wheel according to preset four-wheel steering characteristics, comprising
steps of turning the front wheels, measuring the actual turning angle of at least one of the front wheels and the actual turning angle of at least one of the rear wheels by which the rear wheel is turned in response to the turning of the front wheels, thereby detecting the actual relation between the turning angles of the front and rear wheels, and checking whether the actual four-wheel steering characteristics of the vehicle deviate from the preset four-wheel steering characteristics by referring the actual relation between the turning angles of the front and rear wheels to the preset four-wheel steering characteristics; - wherein said four-wheel steering system is provided with a fail-safe mechanism for fixing the rear wheels to the straight-ahead position irrespective of the front wheel turning angle when any failure in the mechanism for turning the rear wheels is detected, and in which said fail-safe mechanism is actuated after the step of turning the front wheels and prior to the step of measuring the actual turning angle of the front and rear wheels.
Specification