變速箱開發(fā)中的全自動驗證測試

0 引言

0 Motivation

在變速箱開發(fā)過程中，上百種的樣件變速箱被組裝用于內(nèi)部試驗和客戶的測試。整車制造商也需要樣件變速箱對其整車進行優(yōu)化。在安裝在整車上和發(fā)貨前，樣件變速箱需要進行包含重要功能的驗證測試。在這里，驗證測試由特殊的電機作為驅(qū)動的臺架組成。如圖1，變速箱被電機驅(qū)動，輸出端可通過變速箱內(nèi)部零件鎖止或者安裝由渦流制動的制動器。

傳統(tǒng)的做法是人工控制測試臺（轉(zhuǎn)速和扭矩）和變速箱的功能（換擋）。這意味著，在測試的時候操作者通過用戶界面或者按鈕手動調(diào)整或者激活每個測試步驟?；跁r間序列的測量數(shù)據(jù)被分析和顯示在在線的顯示器上。對于數(shù)據(jù)的評價非常主觀并且很難與極限值進行比較。最后導致的結(jié)果是，只有非常粗糙的數(shù)據(jù)被記錄了下來。這對數(shù)據(jù)統(tǒng)計分析非常不利。

During the course of transmission development，hundreds of prototype transmissions are assembled，both for internal trials and for customer tests.The development partners（vehicle manufacturers）also require the prototypes for overall vehicle optimization in development.Prior to installation in the vehicle or to delivery to customers，the prototype transmissions undergo a release test run that tests the most important basic functions.In the case described here，the release test is performed on a special electric test bench as shown in Fig.1，whereby the transmission is driven by an electric motor and the output side can be optionally braked or put under a load torque by an eddy current brake.

The conventional method is to manuallycontrol or actuate both the test bench（speed and torque）and the transmission functions（gear changes）.This means that during the test run，the test bench driver manually actuates or adjusts the individual test steps and events on a user interface or by pushing buttons.The time sequences of the measurement data are displayed and analyzed online on the screen.This evaluation is very subjectively colored and comparison with strict limit values can be difficult.At the end of the test run in the conventional procedure，only the raw data from the measuring is archived.This makes statistical analysis more difficult and evaluations made may not be immediately understandable later.

圖1 測試臺Fig.1 Test bench

為此設計了一套自動化的驗證測試的分析方法，該方法可確保測試的重復性，并且可以對測量數(shù)據(jù)進行自動測量、評價，包括與極限值的比對結(jié)果（OK／NOK）。另外還能對特征值進行自動報告、自動統(tǒng)計記錄以及自動評估。同時該方法還可以用于對新型變速箱（新概念和新功能）自動測試程序的開發(fā)和將該測試方法應用與量產(chǎn)的EOL測試臺上。

The objective on introduction of the automated release test run described here was to design the test procedure including pre-conditioning to be reproducible so that it would also be possible to achieve automated evaluation of the measurement data，including OK／NOK evaluation with respect to defined limit values.Additionally，automated reporting as well as statistical recording and evaluation of characteristic values were implemented.Another objective is to develop automatic test procedures for new transmission concepts or new functions and to transfer them to the EOL（End Of Line）release test bench in volume production assembly.

1 測試流程

為了優(yōu)化測試搭建時間，臺架布置被設計成無輸出端連接的且變速箱的所有功能均能被驗證的形式。整個自動驗證測試由9個階段組成。具體如圖2。

測試臺的運行由程序自動控制，這里使用的是ZF的PASU系統(tǒng)（基于UNIX的測試臺自動化控制系統(tǒng)）。程序采用分步的運行模式，并且由于在其中包含和變速箱通訊的CAN接口，所以要求軟件柔性化設計來匹配相應的變速箱的CAN需求和不同的換擋曲線。在開始進行試驗前，變速箱的液位由人工進行調(diào)整。并且對各個檔位進行換擋保證變速箱油進入各個離合器。變速箱的液位調(diào)整是在P擋下參照并且通過液位螺栓孔來進行的。這時也對變速箱無負載下的駐車檔功能也進行了驗證。

圖2 在自動驗證測試中的測試階段Fig.2 Test phases in the automated release test run

1.1 階段1：排氣

首先進行的是排氣程序，主要是通過對單獨的離合器施加連續(xù)的壓力脈沖來實現(xiàn)。每次，為了防止鎖死，兩個離合器交替的被脈沖驅(qū)動。這個測試程序和在量產(chǎn)線上的終驗收測試臺（EOL）的測試程序一致。進行排氣的目的是識別和降低由空氣導致的壓力形成的延遲。為了評價和分析排氣階段和壓力形成過程，單個離合器的填充脈沖壓力以疊加曲線的方式進行顯示。

1.2 階段2和階段3：暖機和換擋

這個階段包含對所有的檔位進行結(jié)合（含液力變矩器鎖止離合器），并且在固定檔位且中度負荷下對變速箱進行暖機使其到達運行溫度。同時對各個檔位的傳動比進行檢查。

1.3 階段4，離合器填充

通常自動變速箱里的離合器直接連接兩個傳遞扭矩的軸系或者齒輪零部件，它的多片摩擦片組由帶內(nèi)齒的摩擦片，帶外齒的摩擦片和摩擦片保持架組成。如下圖3所示。

圖3 8HP50的離合器CFig.3 Clutch C in the 8HP50

在這里由活塞來驅(qū)動多片摩擦片組，為了實現(xiàn)這個目的，潤滑油被注入活塞腔形成壓力驅(qū)動活塞。當壓力消失后由碟形彈簧對活塞進行回位。

當測試運行時每個離合器被方形脈沖驅(qū)動5次，每次通過強制鎖死變速箱內(nèi)部原件建立扭矩。這意味著在某個檔位下不僅在檔的三個離合器被結(jié)合，而且第四個離合器也被結(jié)合。這時，由于液力變矩器鎖止離合器的作用，變速箱的輸入轉(zhuǎn)速被降低到一個很低的區(qū)間。

這個階段的主要目的是對離合器填充特征進行評價。如果是帶壓力傳感器的樣品變速箱，可以通過離合器壓力傳感器進行評價。如果是量產(chǎn)的變速箱（不帶壓力傳感器）可以通過轉(zhuǎn)速和扭矩曲線來進行評價。

如下的特征值用于對填充階段進行評價：

關閉的反應時間，填充壓力，填充時間和打開的反應時間和排空時間。如圖4。

圖4 離合器填充測試Fig.4 Testing clutch filling

反應時間是從換擋命令開始（電信號）到第一個壓力反饋結(jié)束。影響反應時間的因素有電流的泄漏、CAN的通訊時間、閥體內(nèi)部閥的慣性和摩擦力、潤滑油的特性。填充壓力的影響因素有碟形簧的簧力和活塞的摩擦力。它是由壓力建立階段的活塞的移動距離來決定的。填充時間是從第一個填充壓力的時間開始計算，然后壓力增加到完全有效值使其快速填充，使活塞到達多片摩擦片組的時間結(jié)束。從另外一方面這個填充時間反應了離合器的間隙，或者活塞到摩擦片組的行程。當離合器打開時，其反應時間是從壓力明顯下降開始到排空時間直至壓力完全卸除終止。碟形簧的簧力和密封件直接對排空時間產(chǎn)生影響。

當無法測量變速箱離合器的壓力時，填充時間的評價通過換擋信號和和渦輪的轉(zhuǎn)速來進行。測量值通過內(nèi)置于程序的額定值進行比較，來判斷OK或者NOK。另外這些值被轉(zhuǎn)換為Excel格式用于統(tǒng)計分析。

1 Procedure

In order to save setup time when necessary，the test procedure is designed so that all important transmission functions can also be tested without the output side being connected.The test procedure of the automated release test run consists essentially of 9 phases，as shown in Fig.2.

The test bench is controlled by a step control program that runs automatically.The equipment used here is a ZF test bench automation software（PASU）on a UNIX basis.The step control program also includes the transmission control via a corresponding CAN interface.This requires the implementation of software modules tailored to the variants and containing the corresponding CANspecifications as well as the appropriate shift sequences.

Before the start of the test run itself，the transmission is pre-conditioned manually as this is necessary to adjust the oil level.This entails shifting all gears for the first time to fill all the clutches.The oil level is adjusted in the running transmission via the oil overflow bore in position P.Also included here is a manual parking lock check in load-free state.

1.1 Phase 1：Venting cycle

The automated test run starts with a newly introduced venting cycle which involves applying an individual number of consecutive pressure impulses to each clutch.Each time，two different clutches receive impulses together in an interlaced sequence in order to avoid force locking.This procedure is already matched to the procedure on the End of Line（EOL）test bench in volume production assembly.The purpose of the venting cycle during pre-conditioning is in particular to identify and reduce delays in pressure buildup caused by original air.To evaluate the venting cycle，the filling impulses of one clutch are shown in an overlapping way so that the pressure buildup can be analyzed.

1.2 Phases 2 and 3：Warming up and changing gears

This is followed by changes into all gears including engaging the lock-up clutch and a constant-speed drive under medium load to warm the transmission up to operating temperature.At the same time，the procedure tests whether the individual gears are engaged，force locking is created，and the corresponding gear ratios are achieved.

1.3 Phase 4：Clutch filling

Typically，the clutches in automatic transmissions connect two torque-carrying shafts or gearset components to each other and consist of a multidisk package with outer and inner multidisks each held in a multidisk carrier，as shown in Figure 3.

The task of the piston is to compress the multidisk package，and for this purpose pressurized oil is applied to the corresponding surface inside the piston chamber.The disk springs open the clutch in the non-pressurized state.

During the test run，each clutch is closed five times under load with a square pulse.Each time，force locking is created even without a connected output side by locking the transmission internally.This means that the clutch to be tested is activated as the fourth clutch while one gear is already activated by three engaged clutches.During this process，the speed of the transmission input shaft is braked at low speed against the torque of the open lock-up gear／torque converter.

In this phase，the filling behavior of the clutch in question is evaluated.In the case of prototype transmissions in which pressure connections of clutch pressures are installed，the pressure characteristics are evaluated.In the case of transmissions without pressure connections（e.g.with volume production housings），the speed and torque curves can be used for evaluation.

Comparative values are evaluated for the following characteristics relating to clutch filling：response time for closing，filling pressure，filling time and response time for opening as well as emptying time，as shown in Fig.4.

The response time when closing results from the time difference between the shift command（electric signal）and the first pressure reaction.The response time is influenced by low-dispersion current times and the task time of the CAN as well as by inertia and frictional forces of the valves and the oil columns to be moved.The filling pressure of the clutch is mainly influenced by the spring force of the return element（disk spring）and the piston frictional forces.It is determined by the pressure level that builds up while the piston moves.The filling time is the time difference between the first pressure reaction and the pressure increase during the effective rapid filling when the piston reaches the multidisk package.It is an indicator of the clutch clearance，or the piston stroke up to contact with the multidisk package.In the case of opening，the response time results from the shift command to the first significant pressure drop and the emptying time up to complete pressure loss in the clutch.The multidisk spring force and the sealing elements again play a role in the emptying time.

In the case of transmissions without pressure connections，the rapid filling time is evaluated as the difference between the shift command up to the reaction of the turbine speed（speed of intake）.The measured values are automatically compared with the defined limit values and correspondingly evaluated as OK or NOK.Additionally，the values are entered in an XLS file and statistically evaluated there.

1.4 階段5和階段6：升溫和泄漏測試

為了測量變速箱內(nèi)部的泄漏，變速箱的油溫需要上升到100°C左右。變速箱的泄漏通過轉(zhuǎn)速飽和度來確定。這意味著，在額定的系統(tǒng)壓力下，油泵泵出的油量可以轉(zhuǎn)換為泄漏油量的測量。在系統(tǒng)壓力15 bar且所有離合器打開狀態(tài)下對第一個泄漏比較值進行測量。轉(zhuǎn)速的飽和度在這里基于油泵的特征曲線、泵出的油量、液壓模塊的泄露和泵的內(nèi)部泄漏。單個離合器的泄漏通過離合器結(jié)合時比較基礎泄漏和總泄漏來決定。

測試的過程是由轉(zhuǎn)速降低和升高組成。從期望的飽和度降低到明顯的非飽和區(qū)間，然后從非飽和區(qū)間升高到飽和區(qū)間。從而通過轉(zhuǎn)速可以測得在什么點對應了15 bar的系統(tǒng)壓力。這樣就可以和額定值進行比較，并且記錄統(tǒng)計。

圖5 泄漏測試Fig.5 Leakage measurement

1.5 階段7：液壓脈沖儲油功能測試

液壓脈沖儲油功能（HIS）是基于發(fā)動機啟停技術(shù)設計，它用于支持油泵的快速啟動.在變速箱運行過程中多余的油儲存于HIS元件中，當快速啟動時元件中的油被釋放入液壓控制單元的主回路和離合器中?；诖?，三個離合器在300 ms內(nèi)被足夠壓力的油液填充并結(jié)合。

HIS測試在變速箱靜止時（油泵靜止時）進行。HIS功能在系統(tǒng)壓力降低為0時被激活。液壓脈沖的高度和持續(xù)時間被用于對其功能的驗證。這些數(shù)據(jù)也被保存用于分析。

1.6 階段8：額外的冷卻系統(tǒng)

重載變速箱的應用可以加載額外的冷卻系統(tǒng)。當離合器在高負載下壓力超過極限值結(jié)合時，系統(tǒng)自動提供額外的冷卻液（油量）。此功能通過測量在穩(wěn)定工況下（離合器壓力增加或者降低到限值）次要壓力的不飽和度。如果額外冷卻系統(tǒng)功能正確，次要壓力會明顯下降。如圖6所示。

圖6 額外冷卻系統(tǒng)的測試Fig.6 Testing the additional cooling system

1.7 階段9，倒檔

因為有缺陷的零部件可以導致拖曳轉(zhuǎn)矩的增加和離合器溫度的上升，所以倒檔的速度耐久強度在一個單獨的階段進行。測試時，對轉(zhuǎn)速做一個小的改變進而變速箱的拖曳轉(zhuǎn)矩進行監(jiān)控。

2 數(shù)據(jù)分析和報告

數(shù)據(jù)的分析基于IMC的FAMOS軟件。通過使用擴展命令包安裝的功能，測試的數(shù)據(jù)通過序列被編輯并評價。

在分析時的對話框?qū)煌臏y試階段，其用于分析的結(jié)構(gòu)由50個序列，子序列，和子對話框組成。（見圖7）。特殊的特征序列可以被動態(tài)編輯。例如：當用于離合器分析時，離合器的名字，離合器的壓力，還有測試的觸發(fā)信號都被傳遞到這個序列。

圖7 FAMOS分析序列（摘要）Fig.7 FAMOS analysis sequences（excerpt）

通過FAMOS的可編輯對話框，用戶界面可以被自定義如圖8，在定義好用戶界面的測試臺，用戶可以直接預先選擇。例如：單個獨立的階段，變量和自動目標值的比對，可視化的結(jié)果等。并且用于統(tǒng)計分析的重要的特征值被自動導入數(shù)據(jù)庫。

另外，為了文檔管理，包含重要特征數(shù)據(jù)的PDF格式的測試報告可以通過按鈕一鍵自動生成。如圖9所示。

3 結(jié)論

測試臺覆蓋了對所有的類型的8HP（通用型，全驅(qū)型）進行安裝和進行自動測試。每個測試的運行時間（含搭建）據(jù)尺寸的不同大約在20-25分鐘。

變速箱功能參數(shù)的極限值由特殊的變速箱通過實驗來確定。在這里變速箱的尺寸和特征參數(shù)被故意設置到偏差的極限值。同理，離合器的間隙和碟形簧的簧力也被設定到極限值。

圖8 在臺架上FAMOS的分析Fig.8 FAMOS analysis on the test bench

此外，錯誤模擬也通過特殊準備的樣件變速箱來進行。參數(shù)被故意設置到偏差外或者零部件通過錯誤的安裝。通常下，測試結(jié)果會超過限值。

由于需要在試驗臺上對變速箱的控制系統(tǒng)和CAN通訊進行評價，可能會有非常多的錯誤導致測試程序的順利運行和評估的中斷。為了避免此類情況的發(fā)生，一個不斷優(yōu)化的程序段被用于對測試臺程序控制和評估進行故障分析。

由于自動化，整個測試質(zhì)量被明顯的改進，測試程序現(xiàn)在可以以可重復性的方式自動比對實測值和額定值。并且可以自動分析獲得統(tǒng)一精確的結(jié)果。再者，通過對自動變速箱的控制和柔性化的離合器控制系統(tǒng)，可以集成額外的測試功能模塊。在這之前的人工控制模式下是無法實現(xiàn)的。

通過記錄統(tǒng)計分析離合器的泄漏值和特征參數(shù)，可以讓我們在產(chǎn)品開發(fā)的早期獲得大量的參數(shù)。這些信息可以引用到新產(chǎn)品開發(fā)和程序的標定當中。

1.4 Phases 5 and 6：Warming up and leakage measurement

For measurement of the internal transmission leakages（＂consumers＂），the transmission is first warmed up to an increased operating temperature of 100°C.The internal transmission leakages are indirectly determined by measuring the saturation speed.This means the speed at which a defined system pressure threshold is reached and the oil pump transports exactly the quantity that is＂consumed＂as leakage in the transmission at the corresponding operating point.The first comparison value for the base leakages is measured without engaged clutches at a pressure threshold of 15 bar.The saturation speed measured here can be converted based on the geometric pump capacity into the delivery quantity that corresponds to the internal leakage of the hydraulic control unit plus the internal pump leakage.The individual clutch leakagesare calculated from the difference between the base leakage and the total leakage when the corresponding clutch is engaged.

圖9 測試報告Fig.9 Report

The procedure during this measurement is that the input speed is reduced in a double ramp from above the expected saturation speed to significantly below it，then increased again，as shown in Figure 5.Then the speeds determined at which the system pressure falls below or rises above the 15 bar threshold are evaluated.The comparison values de-termined in this way are also compared with the defined limits and made accessible for statistical analysis in a database.

1.5 Phase 7：Hydraulic impulse oil storage testing

The hydraulic impulse oil storage（HIS）in the transmission hydraulically supports the oil pump during rapid starting（start-stop function）.The HIS is filled during operation with excess oil which on rapid starting is released into the primary hydraulic circuit of the transmission supplying the clutches.This way，three clutches can be filled and engaged within 300 ms to generate force locking for setting off.

HIS testing is performed with the transmission stationary and correspondingly stationary oil pump.The HISis triggered when the system pressure drops to zero.The height and length of the pressure impulse in the system during triggering the store are analyzed.

1.6 Phase 8：Additional cooling system

The additional cooling system is an optional functionality for heavy applications.When the clutch is engaged，an increased volume flow of coolant is automatically applied when the clutch pressure exceeds a threshold value during gear changes under high load.The function is tested by measuring an unsaturated secondary pressure at a stationary operating point while the corresponding clutch pressure is increased and decreased again beyond the threshold value in a double ramp.If the additional cooling system is functioning correctly，the secondary pressure drops significantly，as shown in Fig.6.

1.7 Phase 9：Reverse gear

The speed endurance strength of the reverse gear is tested in a separate phase because faulty components can cause an increased drag torque with corresponding increased heat in a clutch.During the test，the transmission drag torque is monitored over a slow speed ramp and for evaluation automatically compared with the fixed limits.

2 Data analysis and reporting

The analysis is performed with the measured data analysis tool FAMOS from IMC.This enables programming of evaluation sequences with pre-installed functions from an extensive command pool.

The entire software architecture for the analysis consists of some 50 sequences，sub-sequences，and sub-dialogs for the individual test phases which are accessed by the analysis dialog during analysis（see Fig.7）.A special characteristic of the sequences is that they can by parameterized dynamically，i.e.when a clutch is analyzed，the name of the clutch，the clutch pressure，and the measurand of the triggering signal are transferred to the sequence.

With the help of the FAMOS Dialog Editor，a user interface was designed as shown in Figure 8.Working with this directly on the test bench，the user can pre-select e.g.the variables and subsequently start the automatic analysis including target value comparison of the individual test steps，then visualize the results.Important characteristic values are automatically input into the database，where they are available for statistical analysis.

Additionally，for the purposes of documentation，a report can be generated at the push of a button with the most important characteristic values and output in pdf format，as shown in Figure 9.

3 Results

The installation and implementation of the automated test run for 8HP transmissions with standard and four-wheel drive is complete for all three sizes.We were able to roughly halve the testing time to approx.20-25 min（depending on size），plus setup time.

The limit values（target values）for the main transmission functions were verified by experiments with limit sample transmissions.Here，the dimensions or characteristic values of the corresponding characteristics were deliberately set to the tolerance limit.In the case of clutches，this applies for instance to the clutch clearance and the multidisk spring force.

Additionally，error simulations were carriedout with specially prepared prototype transmissions where characteristics were deliberately set outside the permitted tolerances or parts were installed in a faulty way.As expected，the test results for these transmissions were outside the permitted limits.

Due to the complexity of both the transmission control system and the CAN communication on the test bench as well as the evaluation，there is a broad scope for error which can disrupt the smooth running of the test program，including the evaluation.For this reason，an ongoing optimization phase is designed to enable troubleshooting both in the test bench control program and also in the evaluation routines.

A significant improvement in the test run quality is shown by the fact that，due to the automation，the test program now runs in a reproducible way so that the analysis by means of target／actual comparisons is more objective.Additionally，the automation capability of the analysis enables a complete evaluation and seamless documentation of the results.Furthermore，the automatic transmission control makes it possible to integrate additional test modules with flexible clutch control systems.This would not be feasible in practice with conventional manual control.

The recording and statistical analysis of leakage values and characteristic values of clutch filling behavior allow us to reach conclusions about the spread of parameters as early as the development stage.This information can therefore be applied at an early stage in new designs or in the calibration of necessary program maps in the software.

Automated Release Test Run in Transmission Development

Dipl.-Ing.（FH）Rolf Braun，Maximilian Gaβmann，Zhang Jilin，Dr.Rolf Gall，ZF Friedrichshafen AG，F(xiàn)riedrichshafen

全自動驗證測試建立的目的是為了增加樣件變速箱的驗證測試效率并對其進行比較分析。因此分步程序被用于對測試臺的控制來確?？芍貜偷臏y試流程。這意味著新的測試階段程序可以直接插入到舊的測試階段程序中，這在以往的人工操作中是很難實現(xiàn)的。數(shù)據(jù)測量由FAMOS測量工具實現(xiàn)。良好的人機界面可以讓操作員對不同的模塊結(jié)果直接進行可視化預讀。為了對測試結(jié)果進行管理，包含變速箱的主要功能的數(shù)據(jù)的測試報告由系統(tǒng)自動生成。

To increase the efficiency of release testing of prototype transmission，and to make comparative analysis and evaluation possible，an automated release test run was established.

變速箱 全自動驗證測試 離合器測試

Transmission Automated release test Clutch test

U467.3

B

1006-8244（2015）04-003-11

In it，a step control program for the test bench control unit ensured a reproducible test procedure.This meant that additional，new test phases could be integrated that were not possible in manual operation.The measurement data is analyzed with the FAMOS measurement data analysis tool.A user-friendly user interface allows the test bench driver to visualize the results of the individual test modules as soon as they are completed.The permitted limit values are shown simultaneously.To document the results，a release test report is automatically issued，detailing the key functional data of the transmission.