CN106931157A - A kind of double-clutch speed changer shift control method for avoiding dual-clutch gear-shifting power cycle - Google Patents

Abstract

The invention discloses a dual-clutch transmission shift control method for avoiding dual-clutch shifting power cycle, which is characterized in that: when the dual-clutch automatic transmission is shifting, the separation and engagement of the dual clutch is controlled and the rotational speed of the engine is adjusted, thereby It avoids the shifting power cycle generated by the dual clutch, reduces the shifting power consumption of the dual clutch, and at the same time reduces the shifting impact, and improves the shifting smoothness of the dual clutch transmission.

Description

A Shift Control of Dual Clutch Transmission Avoiding Dual Clutch Shift Power Cycle method

technical field

The invention relates to a method for controlling automatic gear shifting of a vehicle, in particular to a method for controlling gear shifting of a dual-clutch transmission that avoids power cycles of dual-clutch gear shifting.

Background technique

Dual Clutch Transmission (DCT) is a new type of automatic transmission developed on the basis of manual transmission. It uses two clutches for power transmission. When the first clutch transmits the current gear, the second clutch transmits power. The first clutch can be used to preset the shift-in gear. When the switch between the current gear and the shift-in gear needs to be completed, the first clutch releases the current gear, and the second clutch engages the shift-in gear at the same time. DCT not only has the flexibility of a manual transmission, but also has the comfort of an automatic transmission. There is no obvious power interruption during the entire shifting process, and at the same time, the shifting response is fast. DCT is favored by people for its excellent performance and is rapidly promoted. application.

The special structural characteristics of DCT reduce the power loss when shifting gears, but due to the existence of power cycle, the longer the clutch shifting time, the smaller the impact, but the greater the wear of the clutch, on the contrary, the shorter the clutch shifting time, which is beneficial to improve The wear condition of the clutch, the greater the impact, the worse the smoothness of shifting, so the shifting time and shifting impact when there is a power cycle become a pair of contradictions that are difficult to reconcile during power transfer. Therefore, power cycling is easy to occur during the DCT shifting process, resulting in power loss, reduced smoothness of shifting and damage to shifting clutch components.

Contents of the invention

In order to avoid the disadvantages of the above-mentioned prior art, the present invention proposes a dual-clutch transmission shift control method that avoids the dual-clutch shift power cycle, in order to be able to shift gears through the dual-clutch transmission when the dual-clutch automatic transmission is shifting. The separation and engagement control of the engine and the speed adjustment of the engine prevent the clutch from generating shifting power cycle, reduce the shifting power consumption of the dual clutch, reduce the shifting impact at the same time, and improve the shifting smoothness of the dual clutch transmission.

The present invention adopts following technical scheme in order to achieve the above-mentioned purpose of the invention:

A kind of double-clutch transmission shifting control method of the present invention avoiding double-clutch shifting power cycle is characterized in that it is carried out as follows:

Step 1. Reduce the positive pressure of the disengagement clutch, so that the driving disc and the driven disc of the disengagement clutch are in a critical state of separation, and increase the positive pressure of the engaging clutch at the same time, so that the driving disc and the driven disc of the engaging clutch are in engagement Critical state;

Step 2, gradually adjust the positive pressure of the separation clutch and the engagement clutch, and gradually adjust the speed of the engine at the same time, so that the driving disc and the driven disc of the separation clutch gradually increase the friction, and the driving disc of the engagement clutch Engage with the driven disc gradually increasing;

Step 3. When the positive pressure of the separation clutch drops to zero, the driving disk of the separation clutch is completely separated from the driven disk, and the driving disk and the driven disk of the separation clutch are in a complete friction state, corresponding to the The positive pressure of the engaging clutch is the maintaining pressure of the engaging clutch, and the maintaining pressure of the engaging clutch is kept constant until the driving disc of the engaging clutch is fully combined with the driven disc;

Step 4. When the rotating speed of the driving disc of the engaging clutch is equal to the rotating speed of the driven disc of the engaging clutch, the driving disc of the engaging clutch is fully combined with the driven disc, and at the same time continue to increase the positive pressure of the engaging clutch to The rated value of the engagement clutch engagement force.

The characteristics of the automatic transmission shift correction control method according to the present invention are also:

The adjustment of the positive pressure of the separation clutch and the engagement clutch in the step 2 is carried out as follows:

According to the requirements of shift response time, the positive pressure of the disengaging clutch is gradually reduced, while the positive pressure of the engaging clutch is gradually increased, and the friction torque _Tc2 of the engaging clutch satisfies the formula ( 1):

In formula (1): i ₁ is the transmission ratio of the current gear; i ₂ is the transmission ratio of the shifted gear; T _cut1 is the transmission torque of the separation clutch; _R is the radius of the tire; m is the mass of the tire; The total moment of inertia of the rear end of the disc; j _R is the moment of inertia of the wheel.

The adjustment of the engine speed described in the step 2 is carried out according to the following method:

The engine speed is adjusted so that the engine speed is greater than the maximum value between the driven disc speed of the disengaging clutch and the driven disc speed of the engaging clutch.

The rated value of the engaging force of the engaging clutch in step 4 is the positive pressure required to transmit the design torque when the engaging clutch works normally.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. The present invention controls the separation and engagement of the dual-clutch by adjusting the positive pressure of the dual-clutch, effectively reducing the shifting impact and improving the shifting smoothness of the dual-clutch transmission.

2. In the process of separating and combining the dual clutches, the present invention avoids the shifting power cycle when the clutch shifts gears by adjusting the rotational speed of the engine, reduces the shifting power consumption of the dual clutches, and avoids the damage of the dual clutches shifting parts at the same time. Damage, prolonging the service life of dual clutch shifting components.

3. The present invention improves the shifting performance of the dual clutch through the separation and engagement control of the dual clutch and the speed adjustment of the engine, without changing the vehicle hardware system, and only needs to increase the corresponding software program of the control method in the automatic transmission electronic control unit, which can The utility model has strong operability and is applicable to vehicles equipped with different types of dual-clutch automatic transmissions, and has a wide range of applications.

Description of drawings

Fig. 1 is the structural diagram of the dual-clutch transmission of the embodiment of the present invention;

Fig. 2 is a schematic diagram of positive pressure adjustment of two clutches during the shifting process of the dual-clutch transmission of the present invention;

Fig. 3 is a schematic diagram of engine speed adjustment during the shifting process of the dual-clutch transmission of the present invention.

detailed description

In this embodiment, a dual-clutch transmission shift control method that avoids dual-clutch shifting power cycles is to avoid dual-clutch transmissions through the separation and engagement control of the dual-clutch and the speed adjustment of the engine when the dual-clutch automatic transmission is shifting gears. Generate shifting power cycle, reduce shifting power consumption of dual-clutch, reduce shifting impact at the same time, improve shifting smoothness of dual-clutch transmission. Referring to Figure 1-Figure 3, specifically, proceed as follows:

Step 1. The dual-clutch transmission completes power transmission and transmission ratio change through two clutches. Define the clutch for power transmission in the current gear as a disengaging clutch, and the clutch that needs to be shifted into a gear for power transmission as an engaging clutch. Before the conversion, it is first necessary to eliminate the idle stroke of the separation clutch and the engagement clutch, that is, reduce the positive pressure of the separation clutch, make the driving disc and the driven disc of the separation clutch in a separation critical state, and increase the positive pressure of the engagement clutch at the same time, Make the driving disc and driven disc of the engaging clutch in the critical state of engaging, eliminate the idle travel of the separating clutch and the engaging clutch, and make both the separating clutch and the engaging clutch reach the critical state of power transfer, so as to shorten the shifting time of the dual-clutch transmission ;

Step 2. When changing gears, in order to shorten the shifting time, improve the smoothness of shifting, and avoid power interruption, the disengaging clutch that transmits the power of the current gear needs to gradually reduce the power transmission, and the engaging clutch that transmits the power of the shifted gear needs to Gradually increase the power transmission, the separation clutch and the engagement clutch need to carry out power transfer, the positive pressure of the separation clutch and the engagement clutch needs to be gradually adjusted, so that the driving disc and the driven disc of the separation clutch gradually increase the sliding friction, and the driving disc and the engaging clutch The driven disc gradually increases engagement; at the same time, in order to avoid power circulation between the disengagement clutch and the engagement clutch, it is necessary to gradually adjust the engine speed;

Specifically, the adjustment of the positive pressure of the separation clutch and the engagement clutch is carried out in the following manner:

Firstly, the impact degree for evaluating the smoothness of shifting during the shifting process is explained:

The shock degree during the gear shifting process of the vehicle is usually represented by the first derivative of the vehicle acceleration. Since the gear shifting process is short and the vehicle speed does not change significantly, the rolling resistance torque and air resistance torque during the process can be regarded as constants, and the step-by-step derivation of the separation clutch can be obtained. The expression of the jerk degree when the sliding friction and engaging clutch is gradually engaged, where _j1 is the jerk degree when both clutches have no power cycle under the condition of adjusting the engine speed, and _j2 is the jerk degree when the disengagement clutch has power cycle.

In formulas (1) and (2): i ₁ is the transmission ratio of the current gear; i ₂ is the transmission ratio of the shifted gear; T _c1 is the friction torque of the separation clutch; T _c2 is the friction torque of the engaging clutch; R is The radius of the tire; m is the mass of the tire; j _B is the total moment of inertia of the rear end of the clutch driven disc; j _R is the moment of inertia of the wheel.

From the above expression of shock degree, it can be seen that the shift smoothness of DCT is mainly affected by the friction torque change rate of the separation clutch Engaged clutch friction torque change rate And whether there are factors such as power cycle.

The expressions of the friction torque change rate T _c1 of the disengaging clutch and the friction torque change rate T _c2 of the engaging clutch are as follows:

In formula (3) and formula (4): is the rate of change of the engagement force of the disengaged clutch and engaged clutch; R _c and r _c are the diameters of the clutch friction discs respectively; μ is the friction coefficient of the clutch friction discs.

It can be seen from formula (3) and formula (4), same It is a proportional relationship, and since the engagement force of the disengaging clutch gradually decreases during the shifting process, and the engagement force of the engaging clutch gradually increases, so is a negative value, is a positive value.

(1) When there is no power cycle in the two clutches, it can be seen from the first expression of formula (1) that by adjusting the change rate of the engagement force of the two clutches, the shock degree can be theoretically realized to be 0.

(2) When there is a power cycle in the disengaged clutch and the engaged clutch transmits torque forward, it can be known from formula (2) The signs of the two coefficients are opposite; it can be seen from the actual process of gear shifting that since one side of the positive pressure of the two clutches increases and the other decreases, It has an opposite positive and negative relationship, so theoretically it cannot be realized by adjusting the engagement force of the two clutches according to the expression of formula (1). The two items cancel each other out, theoretically reducing the shift shock to zero. at the same time, The two terms are derivative terms, which themselves reflect the rate of change of the physical quantity. The longer the change time and the gentler the change, the smaller the value, and the shorter the change time and more intense the change, the larger the value. Due to the existence of power cycle, these two items cannot be eliminated by adjusting the clutch engagement force, so the longer the clutch shifting time in the presence of power cycle, the smaller the impact, but the greater the wear of the clutch; on the contrary, the shorter the shifting time, the greater the impact , but it is beneficial to improve the clutch wear condition.

Therefore, the shifting impact and shifting time (that is, clutch wear) become contradictory quantities when there is a power cycle. In order to reconcile the contradiction between shifting time and shifting shock, it is necessary to establish a system optimization control model based on the minimum value principle. But the control process is extremely complicated. When shifting without power cycle, due to The two items can be mutually offset and eliminated, so there is no contradiction between the shifting time and the shifting impact, and the impact of shifting at any shifting time can be 0, so the power cycle should be avoided when the dual-clutch transmission is shifted. produce.

According to the requirements of shift response time, gradually reduce the positive pressure of the disengaging clutch, and gradually increase the positive pressure of the engaging clutch, and make the friction torque _Tc2 of the engaging clutch satisfy the formula (5), which can ensure The shock degree is 0 during the slipping friction process of power transfer between the two clutches.

Among them, the expression of the transmission torque T _cut1 of the separation clutch is as follows:

In formula (6): is the rate of change of engine torque; j _A is the sum of moment of inertia of the clutch driving disc and its front-end components; T _r is the running resistance torque including rolling resistance torque and air resistance torque.

From the above analysis, it can be seen that it is difficult to solve the problem of smoothness of shifting when there is a power cycle in the shifting process of the dual-clutch transmission. Therefore, the shifting power cycle must be eliminated in the shifting process of the dual-clutch transmission. Realize no power circulation during the shifting process of two clutches.

When the clutch transmits friction torque in the forward direction, the speed of the driving disc of the clutch must be greater than the speed of the driven disc; if the speed of the driven disc of the clutch is higher than the speed of the driving disc, the direction of friction torque transmission becomes from the driven disc to the driving disc. The reverse transfer of friction torque results in power cycling. During the shifting process, if the speed of the driving disc of the clutch is lower than the speed of the driven disc of the disengaged clutch or the engaged clutch, the dual clutch will have a shift power cycle, consume engine power, and the force of the shifting parts will deteriorate, and the smoothness of shifting will be poor. Difficult to solve, in order to avoid the shifting power cycle of the dual clutch transmission, it is necessary to make the speed of the driving disc of the clutch greater than the speed of the driven disc of the disengaging clutch or engaging the clutch. The speed is the same, therefore, the adjustment of the engine speed is carried out as follows:

Adjust the engine speed so that the engine speed is greater than the maximum value between the disengaged clutch plate speed and the engaged clutch plate speed.

Step 3. When the positive pressure of the separation clutch drops to zero, the friction torque transmitted by the driving disc of the separation clutch and the driven disc is zero, the driving disc of the separation clutch is completely separated from the driven disc, and the driving disc of the separation clutch and the driven disc are completely separated. The driven disc is in a complete friction state, and the positive pressure corresponding to the engaged clutch is the maintenance pressure of the engaged clutch. At this time, the driving disc of the engaged clutch and the driven disc are not fully engaged. In order to reduce the impact of shifting and improve the smoothness of shifting , keep the maintaining pressure of the engaging clutch constant until the driving disc of the engaging clutch is fully combined with the driven disc;

Step 4. When the rotational speed of the driving disc of the engaged clutch is equal to the rotational speed of the driven disc of the engaged clutch, the driving disc of the engaged clutch is fully combined with the driven disc. At this time, the maintenance pressure of the engaged clutch is only to ensure the transmission of the shifted gear torque If the engine output torque fluctuates and the driving resistance torque of the vehicle changes, the engaging clutch will slip and cannot adapt to the change of the transmission torque. In order to improve the adaptability of the engagement clutch to the change of the transmission torque, At the same time, it is necessary to continue to increase the positive pressure of the engaging clutch until the rated value of the engaging force of the engaging clutch.

When designing a vehicle transmission, it is necessary to calculate the transmission torque of each gear of the transmission according to the engine parameters, transmission ratio, and vehicle parameters, and calculate the positive pressure of the clutch required for different transmission ratios of the transmission according to the transmission torque of each gear. On the basis of this, a certain degree of redundancy is designed for the positive pressure of the clutch to ensure that the clutch can reliably transmit the engine torque when the vehicle parameters, driving conditions, and driving and handling conditions change. Therefore, the positive pressure of the clutch required for different transmission ratios of the transmission The calculated value plus the pressure design redundancy value is the positive pressure required to transmit the design torque when the clutch is working normally. Therefore, the rated engagement force of the engaging clutch is the positive pressure required to transmit the design torque when the clutch is operating normally.

Embodiment: This embodiment uses the control method of the present invention to carry out shift control to a certain type of 7-speed dual-clutch automatic transmission, and the specific control process is as follows:

Figure 1 is a schematic structural diagram of a 7-speed dual-clutch transmission of a certain model. The first and second gears are selected for shift control, and the other gears are not shown in detail. In Figure 1, C1 and C2 represent clutch 1 and clutch 2 respectively. In the process of shifting from first gear to second gear, clutch 1 is a disengaging clutch, and clutch 2 is an engaging clutch; G1~G7 represent gears at all levels and specify the transmission ratio i _ab is the transmission ratio between gears Ga and Gb (a=1~7; b=1~7), then the transmission ratio i ₁ of the first gear is i ₁₂ ×i ₃₇ , and the transmission ratio i ₂ of the second gear is i ₄₅ × _i67 .

Assume that the initial state of the dual-clutch transmission is that the clutch C1 is engaged, the clutch C2 is disengaged, and it works in first gear. Now shifting from the first gear to the second gear, the second gear synchronizer is pre-engaged (the synchronizer is not shown in Figure 1, and the state shown is the state in which both the first and second gear synchronizers are engaged), and the clutch C2 is still disengaged at this time; The process continues, the pressing force of the clutch C2 increases gradually, and the pressing force of the clutch C1 decreases gradually. When the clutch C1 is completely disengaged and the clutch C2 is fully combined, the first gear synchronizer is disengaged, and the shifting is completed.

During the shifting process of the dual-clutch transmission, each shifting clutch has three states, namely: disengagement, slipping (combining) and engagement. From the perspective of mathematical expression, the two states of disengagement and friction can be described by the same expression. The difference is that the clutch engagement force is 0 in the disengagement state, which can be regarded as a friction state with no engagement force. Therefore, it can be considered that there are only two states for each shifting clutch: slipping and disengagement, so the shifting process of the dual-clutch transmission has the following four states, namely:

(a) C1 is engaged with C2 sliding friction; (b) C1 is sliding and C2 is sliding; (c) C1 is engaging with C2; (d) C1 is engaged and C2 is engaged Obviously, the state of (d) cannot be established, so the changeover of the dual clutch transmission There are only three states (a), (b) and (c) in the block process.

Referring to Fig. 2, the ordinate of the curve is the positive pressure F of the clutch, where the solid line is the positive pressure of C1 and the dotted line is the positive pressure of C2, then the adjustment of the positive pressure of the two clutches during the shifting process of the dual-clutch transmission is divided into the following stages:

1. 0~t0 stage

The dual-clutch transmission is in state (a). Since i ₁ is greater than i ₂ , the speed of the driven disc of clutch C1 is greater than that of the driven disc of clutch C2, so there is no power cycle phenomenon in C2. If there is a power cycle in C1, the transmission torque T _cut1 of clutch C2 is a negative value, but its initial state is positive, and the period must pass through 0 points. If it passes through 0 points, it is inconsistent with the condition that C1 is always engaged in this state. Therefore, there is no power cycle phenomenon in C1 and C2 in the current state.

2. t0~t3 stage

This stage is the key stage of the shift control of dual-clutch transmission, and can be divided into the following stages:

(1) t0～t1 stage

The dual-clutch transmission is in state (a), the positive pressure of clutch C1 quickly drops to the critical value, and the clutch C1 is in the critical state of disengagement. At this time, the friction torque transmitted by C1 is equal to T _cut1 , and the positive pressure of clutch C2 quickly rises to the critical value. C2 is in engagement critical state.

(2) t1～t2 stage

The dual-clutch transmission is in state (b). At the beginning of the current state, the speeds of the C1 driving disc and the C2 driving disc are both equal to the speed of the C1 driven disc and greater than the speed of the C2 driven disc. At the end of the current state, the speed of the C1 driving disk and the speed of the C2 driving disk are both equal to the speed of the C2 driven disk and less than the speed of the C1 driven disk.

If the speed of the driven disc of the clutch is higher than the speed of the driving disc of the clutch, the transmission direction of the friction torque will change from the driven end to the driving end, and a power cycle will occur. Since the speed of the driven disc of C2 is always lower than the speed of the driven disc of C1, there is no such thing as The working condition of C1 without power cycle and C2 power cycle; if both C1 and C2 have power cycle working conditions, it is equivalent to adjusting the engine speed to make the real-time speed reverse the engine rotation, which is obviously unreasonable; therefore, in the t1~t2 section, if there is no For engine speed adjustment control, C1 must have a power cycle working condition. Therefore, adopting the method of engine speed adjustment to control the shifting of clutches C1 and C2 can effectively prevent C1 from generating power cycle. Refer to Figure 3 for specific measures, and the ordinate of the curve is Speed n, where the solid line is the speed of the C1 driven disc, the long dashed line is the speed of the C2 driven disc, and the short dashed line is the engine speed. The specific adjustment method is as follows:

The positive pressure of clutch C1 can decrease linearly according to the predetermined friction time, and the clutch C2 needs to operate according to the control mode of positive pressure of C1, that is, the friction torque T _c2 of clutch C2 satisfies the constraint of formula (5) at time t2, and increases linearly at the rest of the time, And ensure that the engine speed is greater than the maximum value between the clutch C1 and C2 driven disk speeds in the period t1-t2.

(3) t2～t3 stage

The dual-clutch transmission is in state (b), the positive pressure of clutch C1 has dropped to 0, and the positive pressure of clutch C2 is controlled to remain unchanged until C2 is fully engaged. The positive pressure of clutch C2 remains constant during the period t2~t3, which can make the positive pressure of clutch C2 constant during this process. The shock is close to 0, and there is almost no shift shock.

3. t3~t4 stage

The dual-clutch transmission is in state (c), the clutch C2 is fully engaged, and its positive pressure is rapidly increased to the rated value of the clutch engagement force.

So far, the dual-clutch shift control of the 7-speed dual-clutch transmission from the first gear to the second gear has been completed, which avoids the power cycle generated by the dual clutch during the shifting process, improves the smoothness of shifting, and reduces the wear and tear of shifting parts. damage.

Therefore, adopting the dual-clutch shift control method of the present invention to control the separation and engagement of the dual-clutch can effectively reduce the impact of shifting, improve the smoothness of shifting of the dual-clutch transmission, and avoid shifting power cycles during clutch shifting. , reduce the shifting power consumption of the dual-clutch, and at the same time avoid damage to the dual-clutch shifting parts, and prolong the service life of the dual-clutch shifting parts.

Claims (4)

1. A dual-clutch transmission shifting control method that avoids dual-clutch shifting power cycles is characterized in that it is carried out as follows: Step 1. Reduce the positive pressure of the disengagement clutch, so that the driving disc and the driven disc of the disengagement clutch are in a critical state of separation, and increase the positive pressure of the engaging clutch at the same time, so that the driving disc and the driven disc of the engaging clutch are in engagement Critical state; Step 2, gradually adjust the positive pressure of the separation clutch and the engagement clutch, and gradually adjust the speed of the engine at the same time, so that the driving disc and the driven disc of the separation clutch gradually increase the friction, and the driving disc of the engagement clutch Engage with the driven disc gradually increasing; Step 3. When the positive pressure of the separation clutch drops to zero, the driving disk of the separation clutch is completely separated from the driven disk, and the driving disk and the driven disk of the separation clutch are in a complete friction state, corresponding to the The positive pressure of the engaging clutch is the maintaining pressure of the engaging clutch, and the maintaining pressure of the engaging clutch is kept constant until the driving disc of the engaging clutch is fully combined with the driven disc; Step 4. When the rotating speed of the driving disc of the engaging clutch is equal to the rotating speed of the driven disc of the engaging clutch, the driving disc of the engaging clutch is fully combined with the driven disc, and at the same time continue to increase the positive pressure of the engaging clutch to The rated value of the engagement clutch engagement force. 2. The shift correction control method of the automatic transmission according to claim 1, wherein the adjustment of the positive pressure of the disengaging clutch and the engaging clutch in the step 2 is carried out according to the following method: According to the requirements of shift response time, the positive pressure of the disengaging clutch is gradually reduced, while the positive pressure of the engaging clutch is gradually increased, and the friction torque _Tc2 of the engaging clutch satisfies the formula ( 1): $\frac{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; mR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; mR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ In formula (1): i ₁ is the transmission ratio of the current gear; i ₂ is the transmission ratio of the shifted gear; T _cut1 is the transmission torque of the separation clutch; _R is the radius of the tire; m is the mass of the tire; The total moment of inertia of the rear end of the disc; j _R is the moment of inertia of the wheel. 3. The shift correction control method of the automatic transmission according to claim 1, wherein the adjustment of the engine speed in the step 2 is carried out according to the following method: The engine speed is adjusted so that the engine speed is greater than the maximum value between the driven disc speed of the disengaging clutch and the driven disc speed of the engaging clutch. 4. The shift correction control method of the automatic transmission according to claim 1, characterized in that: The rated value of the engaging force of the engaging clutch in step 4 is the positive pressure required to transmit the design torque when the engaging clutch works normally.