SYSTEM FOR MEASURING THE LENGTH OF A FOOTPRINT OF A TYRE AND METHOD THEREOF
원문보기
IPC분류정보
국가/구분
United States(US) Patent
공개
국제특허분류(IPC7판)
B60C-023/06
B60C-019/00
출원번호
17756028
(2020-11-11)
공개번호
20220402314
(2022-12-22)
우선권정보
IT-102019000021159 (2019-11-14)
국제출원번호
PCT/IT2020/050272
(2020-11-11)
발명자
/ 주소
MANCINELLI, Piero
EVANGELISTI, Andrea
PIERALICE, Enrico
출원인 / 주소
TRELLEBORG WHEEL SYSTEMS ITALIA S.P.A.
인용정보
피인용 횟수 :
0인용 특허 :
0
초록▼
The present invention relates to a system and method for measuring the length of a footprint of a tyre (10). The system comprises a first electronic device (1) and a second electronic device (2), each of which is configured at least to acquire, filter, store and sent data, and a processing unit (3),
The present invention relates to a system and method for measuring the length of a footprint of a tyre (10). The system comprises a first electronic device (1) and a second electronic device (2), each of which is configured at least to acquire, filter, store and sent data, and a processing unit (3), external to said electronic devices (1, 2), configured at least to receive and process the data sent by each electronic device (1, 2), to measure the length of a footprint on the basis of an angle (β) arranged between a first axis (B1) passing through the centre (O) of the tyre (10) and a first contact point (CP1) between a portion of said tyre (10) and the ground and a second axis (B2) passing through the centre of the tyre (10) and a second contact point (CP2) between said portion of said tyre (10) and the ground.
대표청구항▼
1. System for measuring the length of a footprint of a tyre (10), said system comprising: a first electronic device (1) to be positioned, in use, on the inner surface (10A) or on the outer surface (10B) of the tyre (10),a second electronic device (2), to be positioned, in use, in contact with the ri
1. System for measuring the length of a footprint of a tyre (10), said system comprising: a first electronic device (1) to be positioned, in use, on the inner surface (10A) or on the outer surface (10B) of the tyre (10),a second electronic device (2), to be positioned, in use, in contact with the rim (20), on which said tyre (10) is mounted,a processing unit (3), external to said electronic devices (1, 2),wherein:a first reference system xi is associated with the first electronic device (1) in such a way that the axis xi is tangent to the rotation of a first point (P1 which is a point of said tyre (10) in which said first electronic device (1) is applied, and the axis z1 is perpendicular to said axis x1,a second reference system x2, y2, z2 is associated to the second electronic device (2) in such a way that the axis x2 is tangent to the rotation of a second point (P2) which is a point of said rim (20) in which said second electronic device (2) is applied, and the axis z2 is perpendicular to said axis x2,said first electronic device (1) is configured at least to send data to said processing unit (3) and comprises inside:a first inertial measurement unit (12) comprising a first gyroscope (121) and a first accelerometer (122), configured to acquire, by means of said first gyroscope (121), a plurality of values associated at least to the angular velocity around the y axis (ω1y), or, by means of said first accelerometer (122), a plurality of values associated at least to the linear acceleration along the x axis (A1x) or a plurality of values associated at least to the linear acceleration along z axis (A1z),first storage means (15) for storing data,a first logic control unit (11), connected with said first inertial measurement (12) and to said first storage means (15), and configured to: receive from said first inertial measurement unit (12): each value of said linear acceleration along the x axis (A1x), oreach value of said linear acceleration along the z axis (A1z), oreach value of said angular velocity around the y axis (ω1y),filter by means of a first digital filter: each value of said linear acceleration along the x axis (A1x) to obtain a filtered linear acceleration along the x axis (A1x′), oreach value of said linear acceleration along the z axis (A1z) to obtain a filtered linear acceleration along the z axis (A1z′), oreach value of said angular velocity around the y axis (ω1y) to obtain a filtered linear angular velocity around the y axis (ω1y′),identify a first time instant (t1,1D), in correspondence of a first contact point (CP1) between a portion of said tyre (10) and the ground, when said portion of said tyre (10) comes into contact with the ground, and a second time instant (t1,2D), in correspondence of a second contact point (CP2) between said portion of said tyre (10) and the ground, beyond which said portion of said tyre (10) loses contact with the ground; said first time instant (t1,1D) and said second time instant (t1,2D) being respectively: the initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F) associated with said filtered linear acceleration along the x axis (A1x′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F′) associated with said filtered linear acceleration along the z axis (A1z′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F″) associated with said filtered angular velocity around the y axis (ω1y′),calculate the time interval (ΔtD) between said first time instant (t1,1D) and said second time instant (t1,2D),store said first time instant (t1,1D), said second time instant (t1,2D) and said time interval (ΔtD) in said first storage means (15),send said first time instant (t1,1D), said second time instant (t1,2D) and said time interval (ΔtD) to said processing unit (3),said second electronic device (2) is configured at least to send data to said processing data (3) and comprises inside:a second inertial measurement unit (22) comprising a second gyroscope (221), configured to acquire, by means of said second gyroscope (221), a plurality of values associated at least to the angular velocity around the y axis (ω2y),second storage means (25) for storing data,a second logic control unit (21), connected to said second inertial measurement unit (22) and to said second storage means (25), and configured to: receive from the second inertial measurement unit (22) the values of said angular velocity around the y axis (ω2y),filter by means of a second digital filter each value of said angular velocity around the axis y (ω2y) to obtain a respective filtered angular velocity around the y axis (ω2y′),identify a respective time instant t2y′ associated with each value of said filtered angular velocity around the y axis (ω2y′),tore in predetermined time intervals in said second storage means (25) each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,send to said processing unit (3) each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,said processing unit (3) is configured at least to receive data from said first electronic device (1) and from said second electronic device (2) and comprises inside:third storage means (35) for storing data,a third logic control unit (31), connected to said third storage means (35), and configured to: receive said first time instant (t1,1D), said second time instant (t1,1D) and said time interval (ΔtD) from said first electronic device (1),receive the values of said filtered angular velocity around the y axis (ω2y′) sent by said second electronic device (2), as well as the respective time instants t2y′,calculate the mean value (ω2y) of the filtered angular velocities around the y axis associated with said second electronic device (2) in correspondence of each instant of time t2y′ within said time interval (ΔtD), calculate an angle (β) between a first axis (B1) passing through the centre (O) of the tyre (10) and said first contact point (CP1) and a second axis (B2) passing through the center centre (O) of the tyre (10) and said second contact point (CP2), according to the following formula: β=ω′2y·ΔtD.calculate the length of the footprint of the tyre (10) with the following formula: L=2·R0·sinβ2wherein R0 is the rolling radius of the tyre (10). 2. System according to claim 1, characterized in that: the first logic control unit (11) of said first electronic device (1) is configured to send said time interval (ΔtD) to the processing unit (3), when the tyre (10) has completed a predetermined first number of revolutions,and in that:the second logic control unit (21) of said second electronic device (2) is configured to send to the processing unit (3) the values of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′, when the tyre (10) has completed a predetermined second number of revolutions. 3. System according to claim 1, characterized in that: said first digital filter is a first IIR filter; said first IIR filter having preferably a frequency between 0.1 Hz and 1 Hz,and in that:said second digital filter is a second IIR filter; said second IIR filter having preferably a frequency between 0.1 Hz and 1 Hz. 4. System according to claim 1, characterized in that: said first electronic device (1) is configured to receive one or more signals from said processing unit (3) and is provided with a first clock source (16), connected to the first logic control unit (11), said second electronic device (2) is configured to receive one or more signals from said processing unit (3) and is provided with a second clock source (26), connected to the second logic control unit (21), andsaid processing unit (3) is configured to send one or more signals to each of said electronic devices (1, 2) and is provided with a third clock source (36), said third clock source (36) being connected to said third control logic unit (31),and in that:said third control logic unit (31) is configured tosend a synchronism signal to said first electronic device (1) and to said second electronic device (2) to synchronize said first clock source (16) and said second clock source (26) to the third clock source (36). 5. System according to claim 4, characterized in that the third logic control unit (31) of said processing unit (3) is configured to send said synchronism signal, when the tyre (10) has completed a predetermined number of revolutions 6. System according to claim 1, characterized in that said second electronic device (2) coincides with said first electronic device (1), so that the value of the filtered angular velocity around the filtered y axis (ω2y′) of the second electronic device (2) coincides with the value of the filtered angular velocity around the y axis (ω1y′) of the first electronic device (1) and that the mean value (ω′2y) of the filtered angular velocities associated with said second electronic device (2) in correspondence of each time instant within said time interval (ΔtD) coincides with the mean value (ω′1y) of the filtered angular velocities associated with said first electronic device (1) in correspondence of each time instant within said time interval (ΔtD). 7. System according to claim 1, characterized in that said time interval (ΔtD) is defined by a first time instant (t1,1D) in which the value of the filtered angular velocity around the y axis (ω1y′) is maximum and a second time instant (t1,2D) in which the value of the filtered angular velocity around the y axis (ω1y′) is minimum and the mean value of the angular velocities (ω′1y) is given by the sum of said maximum value and of said minimum value, divided by number 2. 8. Method for measuring the length of a footprint of a tyre (10), by means of a system according to claim 1, comprising the following steps: A) acquiring: a plurality of values associated with the linear acceleration along the x axis (A1x) associated with a first electronic device (1), ora plurality of values associated with the linear acceleration along the z axis (A1z) associated with a first electronic device (1), ora plurality of values associated with the angular velocity around the y axis (ω1y) associated with a first electronic device (1),B) filtering: each value of said linear acceleration along the x axis (A1x) to obtain a filtered linear acceleration along the x axis (A1x′), oreach value of said linear acceleration along the z axis (A1z) to obtain a filtered linear acceleration along the z axis (A1z′), oreach value of said angular velocity around the y axis (ω1y) to obtain a filtered angular velocity around the y axis (ω1y′),C) identifying a first time instant (t1,1D), at a first contact point (CP1) between a portion of said tyre (10) and the ground, when said portion of said tyre (10) comes into contact with the ground, and a second time instant (t1,2D), at a second contact point (CP2) between said portion of said tyre (10) and the ground, beyond which said portion of said tyre (10) loses contact with the ground; said first time instant (t1,1D) and said second time instant (t1,2D) being respectively: the initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F) associated with said filtered linear acceleration along the x axis (A1x′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F′) associated with said filtered linear acceleration along the z axis (A1z′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F″) associated with said filtered angular velocity around the y axis (ω1y′),D) calculating the time interval (ΔtD) between said first time instant (t1,1D) and said second time instantE) storing said first time instant (t1,1D), second time instant (t1,2D) and said time interval (ΔtD),F) acquiring a plurality of values associated with at least said angular velocity around the y axis (ω2y) associated with the second electronic device (2),G) filtering each value of said angular velocity around the y axis (ω2y) to obtain a respective filtered angular velocity around the y axis (ω2y′),H) identifying a respective instant time t2y′ associated with each value of said filtered angular velocity around the y axis,I) storing in predetermined time intervals each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,J) calculating the mean value (ω2y′) of the filtered angular velocities around the y axis associated with said second electronic device (2) in correspondence of each time instant t2y′ within said time interval (ΔtD),K) calculating an angle (β) arranged between a first axis (B1) passing through the centre (O) of the tyre (10) and a first contact point (CP1), and a second axis (B2), passing through the centre (O) of the tyre (10) and a second contact point (CP2), according to the following formula: β=ω′2y·ΔtD,L) calculating the length of the footprint of the tyre (10) with the following formula: L=2·R0·sinβ2wherein R0 is the rolling radius of the tyre (10). 9. System according to claim 2, characterized in that: said first digital filter is a first IIR filter; said first IIR filter having preferably a frequency between 0.1 Hz and 1 Hz,and in that:said second digital filter is a second IIR filter; said second IIR filter having preferably a frequency between 0.1 Hz and 1 Hz. 10. System according to claim 2, characterized in that: said first electronic device (1) is configured to receive one or more signals from said processing unit (3) and is provided with a first clock source (16), connected to the first logic control unit (11),said second electronic device (2) is configured to receive one or more signals from said processing unit (3) and is provided with a second clock source (26), connected to the second logic control unit (21), andsaid processing unit (3) is configured to send one or more signals to each of said electronic devices (1, 2) and is provided with a third clock source (36), said third clock source (36) being connected to said third control logic unit (31),and in that:said third control logic unit (31) is configured tosend a synchronism signal to said first electronic device (1) and to said second electronic device (2) to synchronize said first clock source (16) and said second clock source (26) to the third clock source (36). 11. System according to claim 3, characterized in that: said first electronic device (1) is configured to receive one or more signals from said processing unit (3) and is provided with a first clock source (16), connected to the first logic control unit (11),said second electronic device (2) is configured to receive one or more signals from said processing unit (3) and is provided with a second clock source (26), connected to the second logic control unit (21), andsaid processing unit (3) is configured to send one or more signals to each of said electronic devices (1, 2) and is provided with a third clock source (36), said third clock source (36) being connected to said third control logic unit (31), and in that:said third control logic unit (31) is configured tosend a synchronism signal to said first electronic device (1) and to said second electronic device (2) to synchronize said first clock source (16) and said second clock source (26) to the third clock source (36). 12. System according to claim 2, characterized in that said second electronic device (2) coincides with said first electronic device (1), so that the value of the filtered angular velocity around the filtered y axis (ω2y′) of the second electronic device (2) coincides with the value of the filtered angular velocity around the y axis (ω′1y) of the first electronic device (1) and that the mean value (ω′2y) of the filtered angular velocities associated with said second electronic device (2) in correspondence of each time instant within said time interval (ΔtD) coincides with the mean value (ω′1y) of the filtered angular velocities associated with said first electronic device (1) in correspondence of each time instant within said time interval (ΔtD). 13. System according to claim 3, characterized in that said second electronic device (2) coincides with said first electronic device (1), so that the value of the filtered angular velocity around the filtered y axis (ω2y′) of the second electronic device (2) coincides with the value of the filtered angular velocity around the y axis (ω1y′) of the first electronic device (1) and that the mean value (ω′2y) of the filtered angular velocities associated with said second electronic device (2) in correspondence of each time instant within said time interval (ΔtD) coincides with the mean value (ω′1y) of the filtered angular velocities associated with said first electronic device (1) in correspondence of each time instant within said time interval (ΔtD). 14. System according to claim 4, characterized in that said second electronic device (2) coincides with said first electronic device (1), so that the value of the filtered angular velocity around the filtered y axis (ω2y′) of the second electronic device (2) coincides with the value of the filtered angular velocity around the y axis (ω1y′) of the first electronic device (1) and that the mean value (ω′2y) of the filtered angular velocities associated with said second electronic device (2) in correspondence of each time instant within said time interval (ΔtD) coincides with the mean value (ω′1y) of the filtered angular velocities associated with said first electronic device (1) in correspondence of each time instant within said time interval (ΔtD). 15. System according to claim 5, characterized in that said second electronic device (2) coincides with said first electronic device (1), so that the value of the filtered angular velocity around the filtered y axis (ω2y′) of the second electronic device (2) coincides with the value of the filtered angular velocity around the y axis (ω1y′) of the first electronic device (1) and that the mean value (ω′2y) of the filtered angular velocities associated with said second electronic device (2) in correspondence of each time instant within said time interval (ΔtD) coincides with the mean value (ω′1y) of the filtered angular velocities associated with said first electronic device (1) in correspondence of each time instant within said time interval (ΔtD). 16. System according to claim 2, characterized in that said time interval (ΔtD) is defined by a first time instant (t1,1D) in which the value of the filtered angular velocity around the y axis (ω1y′) is maximum and a second time instant (t1,2D) in which the value of the filtered angular velocity around the y axis (ω1y′) is minimum and the mean value of the angular velocities (ω′1y) is given by the sum of said maximum value and of said minimum value, divided by number 2. 17. System according to claim 3, characterized in that said time interval (ΔtD) is defined by a first time instant (t1,1D) in which the value of the filtered angular velocity around the y axis (ω1y′) is maximum and a second time instant (t1,2D) in which the value of the filtered angular velocity around the y axis (ω1y′) is minimum and the mean value of the angular velocities (ω1y) is given by the sum of said maximum value and of said minimum value, divided by number 2. 18. Method for measuring the length of a footprint of a tyre (10), by means of a system according to claim 2, comprising the following steps: A) acquiring: a plurality of values associated with the linear acceleration along the x axis (A1x) associated with a first electronic device (1), ora plurality of values associated with the linear acceleration along the z axis (A1z) associated with a first electronic device (1), ora plurality of values associated with the angular velocity around the y axis (ω1y) associated with a first electronic device (1),B) filtering: each value of said linear acceleration along the x axis (A1x) to obtain a filtered linear acceleration along the x axis (A1x′), oreach value of said linear acceleration along the z axis (A1z) to obtain a filtered linear acceleration along the z axis (A1z′), oreach value of said angular velocity around the y axis (ω1y) to obtain a filtered angular velocity around the y axis (ω1y′),C) identifying a first time instant (t 1,1D), at a first contact point (CP1) between a portion of said tyre (10) and the ground, when said portion of said tyre (10) comes into contact with the ground, and a second time instant (t1,2D), at a second contact point (CP2) between said portion of said tyre (10) and the ground, beyond which said portion of said tyre (10) loses contact with the ground; said first time instant (t1,1D) and said second time instant (t1,2D) being respectively: the initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F) associated with said filtered linear acceleration along the x axis (A1x′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F′) associated with said filtered linear acceleration along the z axis (A1z′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F″) associated with said filtered angular velocity around the y axis (ω1y′),D) calculating the time interval (ΔtD) between said first time instant (t1,1D) and said second time instant (t1,2D),E) storing said first time instant (t1,1D), second time instant (t1,2D) and said time interval (ΔtD),F) acquiring a plurality of values associated with at least said angular velocity around the y axis (ω2y) associated with the second electronic device (2),G) filtering each value of said angular velocity around the y axis (ω2y) to obtain a respective filtered angular velocity around the y axis (ω2y′),H) identifying a respective instant time t2y′ associated with each value of said filtered angular velocity around the y axis,I) storing in predetermined time intervals each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,J) calculating the mean value (ω′2y) of the filtered angular velocities around the y axis associated with said second electronic device (2) in correspondence of each time instant t2y′ within said time interval (ΔtD),K) calculating an angle (β) arranged between a first axis (B1) passing through the centre (O) of the tyre (10) and a first contact point (CP1), and a second axis (B2), passing through the centre (O) of the tyre (10) and a second contact point (CP2), according to the following formula: β=ω′2y·ΔtD,L) calculating the length of the footprint of the tyre (10) with the following formula: L=2·R0·sinβ2wherein R0 is the rolling radius of the tyre (10). 19. Method for measuring the length of a footprint of a tyre (10), by means of a system according to claim 3, comprising the following steps: A) acquiring: a plurality of values associated with the linear acceleration along the x axis (A1x) associated with a first electronic device (1), ora plurality of values associated with the linear acceleration along the z axis (A1z) associated with a first electronic device (1), ora plurality of values associated with the angular velocity around the y axis (ω1y) associated with a first electronic device (1),B) filtering: each value of said linear acceleration along the x axis (A1x) to obtain a filtered linear acceleration along the x axis (A1x′), oreach value of said linear acceleration along the z axis (A1z) to obtain a filtered linear acceleration along the z axis (A1z′), oreach value of said angular velocity around the y axis (ω1y) to obtain a filtered angular velocity around the y axis (ω1y′),C) identifying a first time instant (t1,1D), at a first contact point (CP1) between a portion of said tyre (10) and the ground, when said portion of said tyre (10) comes into contact with the ground, and a second time instant (t1,2D), at a second contact point (CP2) between said portion of said tyre (10) and the ground, beyond which said portion of said tyre (10) loses contact with the ground; said first time instant (t1,1D) and said second time instant (t1,2D) being respectively: the initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F) associated with said filtered linear acceleration along the x axis (A1x′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F′) associated with said filtered linear acceleration along the z axis (A1z′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F″) associated with said filtered angular velocity around the y axis (ω1y′),D) calculating the time interval (ΔtD) between said first time instant (t1,1D) and said second time instant (t1,2D),E) storing said first time instant (t1,1D), second time instant (t1,2D) and said time interval (ΔtD),F) acquiring a plurality of values associated with at least said angular velocity around the y axis (ω2y) associated with the second electronic device (2),G) filtering each value of said angular velocity around the y axis (ω2y) to obtain a respective filtered angular velocity around the y axis (ω2y′),H) identifying a respective instant time t2y′ associated with each value of said filtered angular velocity around the y axis,I) storing in predetermined time intervals each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,J) calculating the mean value (ω′2y) of the filtered angular velocities around the y axis associated with said second electronic device (2) in correspondence of each time instant t2y′ within said time interval (ΔtD),K) calculating an angle (β) arranged between a first axis (B1) passing through the centre (O) of the tyre (10) and a first contact point (CP1), and a second axis (B2), passing through the centre (O) of the tyre (10) and a second contact point (CP2), according to the following formula: β=ω′2y·ΔtD,L) calculating the length of the footprint of the tyre (10) with the following formula: L=2·R0·sinβ2wherein R0 is the rolling radius of the tyre (10). 20. Method for measuring the length of a footprint of a tyre (10), by means of a system according to claim 4, comprising the following steps: A) acquiring: a plurality of values associated with the linear acceleration along the x axis (A1x) associated with a first electronic device (1), ora plurality of values associated with the linear acceleration along the z axis (A1z) associated with a first electronic device (1), ora plurality of values associated with the angular velocity around the y axis (ω1y) associated with a first electronic device (1),B) filtering: each value of said linear acceleration along the x axis (A1x) to obtain a filtered linear acceleration along the x axis (A1x′), oreach value of said linear acceleration along the z axis (A1z) to obtain a filtered linear acceleration along the z axis (A1z′), oreach value of said angular velocity around the y axis (ω1y) to obtain a filtered angular velocity around the y axis (ω1y′),C) identifying a first time instant (t1,1D), at a first contact point (CP1) between a portion of said tyre (10) and the ground, when said portion of said tyre (10) comes into contact with the ground, and a second time instant (t1,2D), at a second contact point (CP2) between said portion of said tyre (10) and the ground, beyond which said portion of said tyre (10) loses contact with the ground; said first time instant (t1,1D) and said second time instant (t1,2D) being respectively: the initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F) associated with said filtered linear acceleration along the x axis (A1x′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F′) associated with said filtered linear acceleration along the z axis (A1z′), orthe initial time instant and the final time instant of a discontinuity portion of a sinusoid (S1F″) associated with said filtered angular velocity around the y axis (ω1y′),D) calculating the time interval (ΔtD) between said first time instant (t1,1D) and said second time instant (t1,2D)E) storing said first time instant (t1,1D), second time instant (t1,2D) and said time interval (ΔtD),F) acquiring a plurality of values associated with at least said angular velocity around the y axis (ω2y) associated with the second electronic device (2),G) filtering each value of said angular velocity around the y axis (ω2y) to obtain a respective filtered angular velocity around the y axis (ω2y′),H) identifying a respective instant time t2y′ associated with each value of said filtered angular velocity around the y axis,I) storing in predetermined time intervals each value of said filtered angular velocity around the y axis (ω2y′) and the respective time instant t2y′,J) calculating the mean value (ω′2y)of the filtered angular velocities around the y axis associated with said second electronic device (2) in correspondence of each time instant t2y′ within said time interval (ΔtD),K) calculating an angle (β) arranged between a first axis (B1) passing through the centre (O) of the tyre (10) and a first contact point (CP1), and a second axis (B2), passing through the centre (O) of the tyre (10) and a second contact point (CP2), according to the following formula: β=ω′2y·ΔtD,L) calculating the length of the footprint of the tyre (10) with the following formula: L=2·R0·sinβ2wherein R0 is the rolling radius of the tyre (10).
※ AI-Helper는 부적절한 답변을 할 수 있습니다.