JP2022025697A

JP2022025697A - Gravity center position estimation method for vehicle

Info

Publication number: JP2022025697A
Application number: JP2020128673A
Authority: JP
Inventors: 冨士男籾山; Fujio Momiyama; 賢治江尻; Kenji Ejiri; 洋塩崎; Hiroshi Shiozaki; 史典相馬; Fuminori Soma; 尚亮畠山; Naoaki Hatakeyama; 博学椋本; Hirotaka Mukumoto
Original assignee: Advanced Smart Mobility Co Ltd
Current assignee: Advanced Smart Mobility Co Ltd
Priority date: 2020-07-29
Filing date: 2020-07-29
Publication date: 2022-02-10
Anticipated expiration: 2040-07-29
Also published as: JP6912635B1

Abstract

To provide a method capable of estimating a gravity center position for any vehicle without limitation on a vehicle structure.SOLUTION: A method prepares a "formula of gravity center position change" derived from simultaneous equations of a "balance formula of lateral movement at vacancy" in which all of the items are grasped and a "balance formula of lateral movement at loading" in which an occupant or load is changed, obtains a "gravity center position change length" by calculating a front shaft position lateral slip angle and a rear shaft position lateral slip angle that are unknown in the formula by using a measured value of a GPS mounted at any position vertically on a vehicle longitudinal central shaft, and obtains a gravity center position at loading by adding the obtained "gravity center position change length" to the "gravity center position at vacancy".SELECTED DRAWING: Figure 1

Description

本発明は、荷物や乗客によって変化する車両の重心位置を、横すべり角と既知の諸元値に基づいて推測する方法に関する。 The present invention relates to a method of estimating the position of the center of gravity of a vehicle, which changes depending on luggage and passengers, based on the side slip angle and known specification values.

車体の重心位置は、荷物や乗客がない空車状態であれば常に一定位置になるが、実際の運行においては荷物の積載量や積載位置、乗客の人数と乗車位置により重心位置は変化する。 The position of the center of gravity of the vehicle body is always constant if the vehicle is empty with no luggage or passengers, but in actual operation, the position of the center of gravity changes depending on the load capacity and position of the luggage, the number of passengers, and the riding position.

自動運転車両が走行するためには、車両制御装置が目標となる移動軌跡を計算し、前記車両が前記移動軌跡を追従するように制御する必要がある。前記移動軌跡は、前記車両の車両重心位置が辿るべき軌跡として計算される。しかし前記したように、前記車両への旅客の乗車や積載によって、前記車両の車両重量および車両重心位置が変化してしまうため、その変化を把握する手段が重要となる。 In order for the self-driving vehicle to travel, it is necessary for the vehicle control device to calculate a target movement locus and control the vehicle to follow the movement locus. The movement locus is calculated as a locus to be followed by the position of the center of gravity of the vehicle. However, as described above, the vehicle weight and the position of the center of gravity of the vehicle change depending on the passenger's boarding and loading on the vehicle, and therefore, a means for grasping the changes is important.

重心位置を検出する方法として、フルエアサスペンション車両であれば各軸の空気ばねの空気圧を検出する方法、各軸の懸架ばね定数から固有振動数を算出して各軸ばね上質量から検出する方法、更に各軸にロードセルを装備する方法が考えられる。しかしながら、フルエアサスペンションによる方法、固有振動数による方法、ロードセルによる方法ともに構造上の制約を伴い。汎用性に欠ける。汎用性があり簡便に装備できる方法が求められる。 As a method of detecting the position of the center of gravity, in the case of a full air suspension vehicle, a method of detecting the air pressure of the air spring of each shaft, a method of calculating the natural frequency from the suspension spring constant of each shaft and detecting it from the mass on each shaft spring. Furthermore, a method of equipping each axis with a load cell can be considered. However, the method using the full air suspension, the method using the natural frequency, and the method using the load cell all have structural restrictions. It lacks versatility. A method that is versatile and can be easily equipped is required.

特許文献１には、アクセル開度と発生する前後加速度から車両重量を推定し、かつ後軸のエアサスペンションの空気圧から後軸荷重を推定し、車両重量から後軸荷重を差し引いて前軸荷重を推定する方法が示されている。 In Patent Document 1, the vehicle weight is estimated from the accelerator opening and the generated front-rear acceleration, the rear axle load is estimated from the air pressure of the rear axle air suspension, and the rear axle load is subtracted from the vehicle weight to obtain the front axle load. The method of estimation is shown.

特許文献２には、後輪軸重に応じて後輪ブレーキ圧を変更する後輪ブレーキ圧変更手段と、前輪のブレーキ圧を検出する前輪ブレーキ圧検出手段と、前記後輪ブレーキ圧変更手段よりも下流側における前記後輪のブレーキ圧を検出する後輪ブレーキ圧検出手段と、制動時における検出された前後のブレーキ圧の関係と、前記後輪ブレーキ圧変更手段の後輪軸重特性とに基づいて後輪軸重を推定する後輪軸重推定手段とを備え、前記推定された後輪軸重に基づいて車両幅方向における車両重心状態を判定することが開示されている。 Patent Document 2 describes the rear wheel brake pressure changing means for changing the rear wheel brake pressure according to the rear wheel shaft weight, the front wheel brake pressure detecting means for detecting the front wheel brake pressure, and the rear wheel brake pressure changing means. Based on the relationship between the rear wheel brake pressure detecting means for detecting the brake pressure of the rear wheels on the downstream side, the detected front and rear brake pressures during braking, and the rear wheel shaft weight characteristics of the rear wheel brake pressure changing means. It is disclosed that the vehicle includes a rear wheel axle weight estimating means for estimating the rear wheel axle weight, and the vehicle center of gravity state in the vehicle width direction is determined based on the estimated rear wheel axle weight.

非特許文献１には、バウンシングとピッチングの固有振動数が計測され乗心地モデルの固有振動数に照して積載量が判定され、更にばね上質量，慣性モーメント，重心位置及び各軸重も乗心地モデル式によって推定されることが記載されている。 In Non-Patent Document 1, the natural frequencies of bouncing and pitching are measured, the load capacity is determined in light of the natural frequencies of the riding comfort model, and the sprung mass, moment of inertia, center of gravity position, and shaft weight are also multiplied. It is stated that it is estimated by the comfort model formula.

特許第６２０２７００号公報Japanese Patent No. 6202700 ＷＯ２０１４／１２２７８６WO2014 / 122786

”自動運転大型トラックのための横運動モデルの積載状態推定,” 籾山冨士男ほか, 自動車技術開論文集, Vol.44, No.6, November 2013, No.2020134847, pp.1377-1382"Estimating the loading state of a lateral motion model for self-driving heavy-duty trucks," Fujio Hiyama et al., Journal of Automotive Technology, Vol.44, No.6, November 2013, No.2020134847, pp.1377-1382

特許文献１によれば、前軸荷重と後軸荷重の比をホイールベースに乗算することで、車両重心位置を推定することができる。しかしながら、車両がエアサスペンションを装備していることを前提とするため、適用できる車両構造が限定されてしまうという課題を残している。 According to Patent Document 1, the position of the center of gravity of the vehicle can be estimated by multiplying the wheelbase by the ratio of the front axle load and the rear axle load. However, since it is assumed that the vehicle is equipped with an air suspension, there remains a problem that the applicable vehicle structure is limited.

特許文献２に開示される方法にあっては、ブレーキ圧を検出することが前提条件となるので、適用範囲が極めて狭い問題がある。また、非特許文献１ではバウンシングとピッチングの固有振動数を算出するための制御ＥＣＵの負担が大きくなる。 In the method disclosed in Patent Document 2, since the detection of the brake pressure is a prerequisite, there is a problem that the applicable range is extremely narrow. Further, in Non-Patent Document 1, the burden on the control ECU for calculating the natural frequencies of bouncing and pitching becomes large.

上記の課題を解決するため、本発明にかかる重心位置推定方法は車体の横すべり角から積載時の車両重心位置を推定する。
諸元の全てが把握されている「空車時横運動のつり合い式」と、乗員ないし積荷が変化した「積載時横運動のつり合い式」との連立方程式から導出される「重心位置変化の式」を用意して、この式に含まれる未知数である「前軸位置横すべり角」と「後軸位置横すべり角」を、車両前後中心軸上の任意の位置に装備したＧＰＳによって検出した「ＧＰＳ装備位置の速度」と「ＧＰＳ装備位置の方位角」と「ヨーレイトの実測値」から計算し、前記「重心位置変化の式」に代入して、「重心位置変化長」を求め、この求めた「重心位置変化長」を「空車時重心位置」に加えて、積車時重心位置を求めるようにした。 In order to solve the above problems, the method for estimating the center of gravity of the vehicle according to the present invention estimates the position of the center of gravity of the vehicle at the time of loading from the side slip angle of the vehicle body.
"Equation of change in center of gravity" derived from the simultaneous equation of "balanced equation of lateral movement when empty" and "balanced equation of lateral motion when loaded" where all the specifications are grasped "GPS equipment position" detected by GPS equipped at any position on the front-rear center axis of the vehicle, which is an unknown number included in this formula, "front axis position side slip angle" and "rear axis position side slip angle" Calculated from the "speed", "azimuth angle of GPS equipment position", and "measured value of yaw rate" and substituted into the above "formula of change in center of gravity" to obtain "length of change in position of center of gravity". "Position change length" is added to "Position of center of gravity when empty" to obtain the position of center of gravity when loaded.

本発明によれば、特定の車両構造に依存せず、容易に、重心位置の変化を推定することができる。 According to the present invention, the change in the position of the center of gravity can be easily estimated without depending on a specific vehicle structure.

ＧＰＳを装備して重心位置変化を検出する場合の説明図である。It is explanatory drawing in the case of having equipped with GPS and detecting the change in the position of the center of gravity.

図１は、左右二つのタイヤを中央にまとめて簡略化した力学モデルである。モデル諸元の符号の説明は図中に示す通りである。添字の無い符号は空車の諸元を示し、添字Ｌ付の符号は積車の諸元を示す。 FIG. 1 is a simplified mechanical model in which two tires on the left and right are grouped in the center. The description of the code of the model specifications is as shown in the figure. A code without a subscript indicates the specifications of an empty vehicle, and a code with a subscript L indicates the specifications of a loaded vehicle.

また、上記の他に車両ＣＡＮから前輪左右平均車輪速と後輪左右平均車輪速を取得して、その両者の余弦から前輪実舵角を把握できる様にしている。 In addition to the above, the front left / right average wheel speed and the rear left / right average wheel speed are acquired from the vehicle CAN, and the front wheel actual steering angle can be grasped from the cosine of both.

この実施例にあってはＧＰＳユニットを車両の前後中心軸上の設置可能な任意の位置に取付け、そのＧＰＳユニットによって検出される横すべり角βasから、以下の式（２１）、（２２）から前軸位置横すべり角β_fGPSおよび後軸位置横すべり角β_ｒGPSを算出し、以下の過程を経て積載に伴う重心位置の変化（Δｌ）を計算し、この変化（Δｌ）を空車時の重心位置に足す（又は減じる）ことで、積載時の車両重心位置を推定する。 In this embodiment, the GPS unit is mounted at an arbitrary position on the front-rear central axis of the vehicle, and the side slip angle βas detected by the GPS unit is obtained from the following equations (21) and (22). Axis position side slip angle β _fGPS and rear axis position side slip angle β _rGPS are calculated, the change in the center of gravity position (Δl) due to loading is calculated through the following process, and this change (Δl) is added to the position of the center of gravity when the vehicle is empty. By (or reducing), the position of the center of gravity of the vehicle at the time of loading is estimated.

諸元の全てが把握されている「空車時旋回運動の式」と、その車両総重量変化が把握されている「積載時旋回運動の式」を連立させることで、積載に伴う重心位置の変化（Δｌ）を計算できる。
空車時旋回運動の式は以下の式（１）、式（２）及び式（３）で表される。 By combining the "formula of turning motion when empty vehicle" where all the specifications are grasped and the "formula of turning motion when loading" where the change in gross vehicle weight is grasped, the position of the center of gravity changes due to loading. (Δl) can be calculated.
The equation of the turning motion when the vehicle is empty is expressed by the following equations (1), (2) and (3).

積車時旋回運動の式は以下の式（４）、式（５）、式（６）で表される。 The equation of the turning motion at the time of loading is expressed by the following equations (4), (5), and (6).

ｍは車両質量、ｖは重心位置の速度、γは遍揺角速度（ヨーレイト）、βは車両横すべり角、βf,βrは前軸及び後軸タイヤの横すべり角、Ccf、Ccrは前軸及び後軸タイヤのコーナリング係数（摩擦係数の概念）、Nf,Nrは前軸及び後軸荷重、ｇは重力の加速度、Lf,Lrは前軸及び後軸から車両重心までの距離、Δｌは、積載に伴う重心位置の変化距離である。 m is the vehicle mass, v is the speed at the center of gravity, γ is the eccentric angular velocity (yorate), β is the vehicle side slip angle, βf and βr are the side slip angles of the front and rear tires, and Ccf and Ccr are the front and rear shafts. Tire cornering coefficient (concept of friction coefficient), Nf and Nr are front and rear shaft loads, g is gravity acceleration, Lf and Lr are distances from the front and rear shafts to the center of gravity of the vehicle, and Δl is with loading. It is the change distance of the position of the center of gravity.

式（４）に式（５）、式（６）を代入することで式（７）、式（８）が導かれる。尚、式（９）～（１２）は式（８）の説明のために記載した。 By substituting the equations (5) and (6) into the equation (4), the equations (7) and (8) are derived. The formulas (9) to (12) are described for the purpose of explaining the formula (8).

上記においてβ_fGPS,β_rGPSは、前軸及び後軸位置の横すべり角、δは前輪実舵角、ｖ_xは車両ＣＡＮから取得する後輪平均車輪速、ｖ_fwheelは前輪ＣＡＮから取得する前輪平均車輪速である。又、式（8）に含まれるβLは、車体横すべり角速度であるが、Δｌを算出する定常円旋回状態では、定常状態であるのでゼロと見做す。 In the above, β _fGPS and β _rGPS are the lateral slip angles of the front and rear axle positions, δ is the actual steering angle of the front wheels, v _x is the average rear wheel speed obtained from the vehicle CAN, and v _f wheel is the average front wheel acquired from the front wheel CAN. Wheel speed. Further, βL included in the equation (8) is the vehicle body side slip angular velocity, but in the steady circular turning state where Δl is calculated, it is regarded as zero because it is in the steady state.

式（8）に含まれるｍLは、車両質量ｍにアクセルストロークの空車電圧に対する積車電圧の変化比（特許文献１による方法）を乗じて求める。 The mL included in the equation (8) is obtained by multiplying the vehicle mass m by the change ratio of the loaded vehicle voltage to the empty vehicle voltage of the accelerator stroke (method according to Patent Document 1).

尚、上記の式（９）は、前輪タイヤ横すべり角の以下の式（13）と後輪タイヤ横すべり角の式(14)から次の様にして導かれる。 The above equation (9) is derived from the following equation (13) of the front wheel tire lateral slip angle and the equation (14) of the rear wheel tire lateral slip angle as follows.

Claims

積載時の車両重心位置の推定方法であって、この推定方法は、諸元の全てが把握されている「空車時横運動のつり合い式」と、乗員ないし積荷が変化した「積載時横運動のつり合い式」との連立方程式から「重心位置変化の式」を導出し、車両前後中心軸上の任意の位置に装備したＧＰＳによって検出した「ＧＰＳ装備位置の速度」と「ＧＰＳ装備位置の方位角」と「ヨーレイトの実測値」から前記「重心位置変化の式」に含まれる未知数である「前軸位置横すべり角」と「後軸位置横すべり角」を算出し、算出した「前軸位置横すべり角」と「後軸位置横すべり角」を前記「重心位置変化の式」に代入して「重心位置変化長」を求め、この「重心位置変化長」を「空車時重心位置」に加えて、積車時の重心位置を求める車両重心位置の推定方法。 It is a method of estimating the position of the center of gravity of the vehicle at the time of loading. "Equation of change in the position of the center of gravity" is derived from the simultaneous equation with "balanced equation", and "speed of GPS equipment position" and "azimuth angle of GPS equipment position" detected by GPS installed at any position on the center axis of the front and rear of the vehicle. And "measured value of yaw rate", "front axis position side slip angle" and "rear axis position side slip angle", which are unknown numbers included in the above "center of gravity position change formula", are calculated and calculated "front axis position side slip angle". And "rear axis position lateral slip angle" are substituted into the above "center of gravity position change formula" to obtain "center of gravity position change length", and this "center of gravity position change length" is added to "center of gravity position when empty" and the product A method for estimating the position of the center of gravity of a vehicle to obtain the position of the center of gravity of the vehicle.

請求項１に記載の車両の車両重心位置の推定方法において、空車時の重心位置からの走行時の重心位置の変化量（Δｌ）は以下の式を用いて算出することを特徴とする車両の重心位置推定方法。

In the method for estimating the position of the center of gravity of a vehicle according to claim 1, the amount of change (Δl) in the position of the center of gravity during traveling from the position of the center of gravity when the vehicle is empty is calculated using the following formula. Center of gravity position estimation method.

請求項２に記載の車両の重心位置推定方法において、前軸横すべり角（β_ｆＧＰＳ）、後軸横すべり角（β_ｒＧＰＳ）を、以下の式を用いて算出することを特徴とする車両の重心位置推定方法。

The vehicle center of gravity position estimation method according to claim 2, wherein the front axis lateral slip angle (β _fGPS ) and the rear axis lateral slip angle (β _rGPS ) are calculated using the following equations. Estimating method.