DE102011111135A1 - Vehicle has drive motor, gearbox driven by drive motor and controller, where controller is formed to combine damping torque control command with motor speed control command in automatic manner - Google Patents

Abstract

The vehicle (10) has a drive motor (12,14), a gearbox (18) driven by the drive motor and a controller. The controller is formed to combine a damping torque control command with a motor speed control command in an automatic manner in order to prevent discontinuity in the engine torque during a change of switching states of the gearbox. An independent claim is also included for a method for minimizing final drive failures in a vehicle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Provisional Patent Application No. 61 / 380,352, filed Sep. 7, 2010, which is incorporated herein by reference in its entirety.

TECHNICAL AREA

The present invention relates to a method and a control system for implementing an engine speed control in conjunction with a damping control of vibrations of the driveline in a vehicle.

BACKGROUND

Hybrid Electric Vehicles (HEV) may selectively use an internal combustion engine and one or more high voltage propulsion engines as alternate or simultaneous power sources to optimize fuel efficiency. That is, an HEV having a full hybrid powertrain may be at least temporarily electrically powered by the prime mover (s), typically immediately upon starting the HEV and while operating below a vehicle threshold speed. One or more drive motors may alternately draw power from an energy storage system and deliver power thereto, as needed. When starting the vehicle or when operating above the threshold speed, the engine may be restarted using one of the drive motors or an auxiliary starter motor and then quickly engaged with a transmission input member.

Various hybrid powertrains manage the torque output of the powertrains, i. H. of the drive motors and an internal combustion engine. Vibrations of the final drive in such vehicles may vary in their severity. Typically, driveline vibration is minimized by eliminating torque oscillations at a specific frequency or frequency range determined using the current gear ratio. Torque removal typically involves driving driveline inputs through signal conditioning filters, which can slow down the overall system response time. The engine speed is used as the only feedback variable to command a single control signal, e.g. As the engine torque. However, single variable feedback / control schemes may possibly provide inadequate vibration damping in a vehicle having multiple powertrains.

Another approach to resolving driveline vibrations in an HEV or, alternatively, in a battery electric vehicle involves the use of active damping of the driveline. In such an approach, desired powertrain and driveline operating conditions are determined and engine damping torque is calculated and added to a commanded engine torque in a manner that varies with the transmission operating mode. The damping and speed control are typically "decoupled" with respect to each other, i. H. the gains needed for damping and speed control are calibrated and applied separately.

SUMMARY

A method is disclosed herein for controlling the speed and damping of a vehicle using an integrated control loop approach. The damping control and the speed control have different purposes. The damping control, as used herein, is intended to reduce transient oscillations of the driveline before they can reach the drive wheels of the vehicle. The speed control is intended to resonate a particular rotating part at a target speed, e.g. Example, the idling of the engine at 700 rev / min or tracking a desired slip in a special clutch by a switching event. In certain modern transmissions having an increased level of complexity, the approach of decoupled damping and speed control during a change in the switching state may produce discontinuities in the applied engine torque. The present approach therefore couples or combines elements of the speed control and the damping control in the same component.

The present method uses proportional-to-integral (PI) control, that is, a proportional gain in parallel with an integrator for the part being controlled. The proportional gain provides a relatively fast error response while the integrator drives the system to a steady-state error of zero, as those terms are understood in the art. The method minimizes driveline disturbances due to switching gains in a vehicle having a PI controller by providing the integral gains before the integrators for first and second drive motors be applied. That is, the damping torque provides the proportional gain for the speed control while an integrator for the part being controlled receives a separate command. The damping and speed control torque are designed together so that the damping torque does not "fight" against a separate PI speed control, e.g. B. when the damping torque goes in one direction and the speed control torque goes in the other direction.

In particular, a method is provided for minimizing driveline disturbances in a vehicle having a controller and a transmission driven by at least one drive motor. The method includes detecting a change in gearshift states of the transmission and using the controller to automatically combine a damping control torque with a motor speed control torque in a closed loop to prevent a noticeable discontinuity in a motor torque applied by the at least one drive motor during the change of the shifting state.

The method may include calculating the engine speed control torque using a proportional gain value from the damping control torque. The automatic combining of the damping torque control with the engine speed control torque may include calculating an error value in the speed of the at least one drive motor and then using the calculated error value to determine a required damping torque to provide the damping control torque.

If two drive motors are used, the method may include multiplying the calculated error value for one of the drive motors by a gain value of the other drive motor before determining the required damping torque.

The method may further include receiving a set of desired targets including an actual engine torque of the engine, a desired axle torque of the axle, wheel speeds of the drive wheels of the vehicle, a desired input speed of the transmission, and / or a desired clutch clutch speed. A desired operating condition is then calculated for the drive motor (s) and the controller outputs a set of reference signals for each of the desired operating conditions. The reference signals may include a calibrated reference value for a damper torque from an input clutch, for the axle torque, for the engine speed, for the transmission output speed, and / or for the engine speed.

The method may also include calculating a speed control torque signal for the at least one drive motor using an engine speed torque control block (MST control block) of the controller and a motor damping torque signal for the at least one drive motor using a controller motor damping torque (MDT) control block is calculated. The speed control torque signal and the engine damping torque signal are then combined to produce a total engine control torque for the at least one drive motor. The engine control total torque may be processed by a model of the vehicle driveline to produce an estimated input clutch damper torque, an axle estimated axle torque, and an estimated wheel speed for the drive wheels. The method may then include routing the estimated damper torque, the estimated axle torque and the estimated wheel speed as inputs to the MDT control block back to the MDT control block.

A vehicle disclosed herein includes at least a drive motor, a transmission driven by the drive motors, and a controller configured to execute the above-mentioned method, and thereby automatically generates a damping torque control command with the proportional portion (P-section) of a proportional integral. Engine speed control command (PI engine speed control command) to combine. In the various embodiments, the integral gains before the integrators for the drive motor (s) are applied to compensate for discontinuity due to switching gains at an applied motor torque, e.g. B. during a change in switching states of the transmission to prevent. In other words, the integral gains are pre-amplified applied to the integrators for the drive motors, which helps to smooth out disturbances caused by gain changes during the change in the switching state.

The foregoing features and advantages and other features and advantages of the present invention will be readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 10 is a schematic illustration of a vehicle having a closed-loop speed controller as disclosed herein; FIG.

2 is a block diagram for a control logic used by the controller of the in 1 shown vehicle can be executed; and

3 FIG. 10 is a flow chart illustrating an approach to gain multiplication of the in 2 described control logic describes.

DESCRIPTION

With reference to the drawings, wherein like reference numerals in the several figures correspond to like or similar components, FIG 1 a vehicle 10 shown that a gear 18 having. The gear 18 receives input torque from multiple on-board torque generators. The torque-generating devices may be an internal combustion engine 16 and / or one or two electric drive motors 12 . 14 include, wherein the actual number of drive motors depends on the vehicle design. Such a construction may be a parallel hybrid as shown in one embodiment, a serial hybrid or other construction. A motor controller 22 that has a control logic 100 provides an engine speed control in conjunction with a regulation of a Endantriebsdämpfungsdrehmoments of the drive or the drive motors 12 . 14 prepared as described in detail below 2 and 3 is disclosed.

Using the in 2 shown control logic 100 the controller combines 22 automatically a damping torque control with the engine speed control in a closed loop to the occurrence of a noticeable discontinuity in the applied engine torque during a change of switching states of the transmission 18 to prevent. The present approach thus addresses a disadvantage in certain existing control designs with separately calibrated final drive damping torque and engine speed control gain values, and avoids the potential conflict between the two different commands.

That is, Proportional Integral (PI) control is provided in existing systems, with the PI control values being directly determined using the speeds that are being controlled. Such systems typically use an input speed to a transmission and various clutch slip speeds as feedback variables in calculating the required control torques. The present approach instead calculates errors in the speeds of the various drive motors and uses these calculated error values to determine the required control torques.

In existing systems, each engine speed that is controlled typically has its own integrator in a PI control scheme, with the input to the integrator given as a desired speed profile or speed minus a measured or derived speed. The error is integrated and multiplied by gains that map a given integrator output to motor torques for various drive motors. This control approach may result in providing output torque when none is desired, as well as speed errors in the drive motors. In addition, gain after the integrator may exacerbate any discontinuities due to a change in a switching state. In contrast, the present controller 22 and its control logic 100 provides an indirect control method that combines engine speed and damping torque in an integrated control approach.

Still referring to 1 contains the gearbox 18 an input element 21 and an output element 33 , Inside the transmission 18 become one or more planetary gear sets 30 and couplings 32 used to apply torque to the output element 33 in a manner dependent on a currently commanded switching state or operating mode. The couplings 32 may be hydraulically operated devices in one possible embodiment. The gear 18 can have so many planetary gear sets 30 and couplings 32 included as needed to provide the desired range of output speeds, in one embodiment, for example, three or more planetary gear sets 30 and four or more couplings 32 ,

The vehicle 10 from 1 may be a hybrid electric vehicle (HEV) or a battery electric vehicle (BEV) according to two possible configurations. In turn, the HEV may be a parallel or a serial hybrid design. The engine 16 can by using an input clutch 11 with the gearbox 18 be selectively connected. Consequently, the input clutch allows 11 in certain drive modes, the selective engagement of a crankshaft 13 the engine 16 with the input element 21 of the transmission 18 and it may include a structure for damping a transient torque, e.g. B. a damping device and a spring, all pulses from the Dampen engine linkage, especially at engine start / stop events. In an HEV or BEV configuration, the drive motor may 12 a motor torque using a motor shaft 120 provide with levels sufficient to the vehicle 10 drive. The drive motor 14 Can in conjunction with the drive motor 12 be used depending on the vehicle configuration, wherein a motor shaft 140 of the motor 14 in some transmission embodiments directly to the driveline of the vehicle 10 connected is.

The drive motors 12 and 14 are each configured as multi-phase permanent magnet / AC induction type electric machines, and may be classified individually for about 60 VAC to 300 VAC or more, depending on the vehicle construction. The motors 12 . 14 are via a high voltage DC busbar 26 , a drive rectifier / inverter module (TPIM) 20 and a high voltage AC busbar 28 with an energy storage system (ESS) 24 electrically connected. The ESS 24 is a battery or other rechargeable energy storage device that utilizes engine torque from one or both engines 12 . 14 can be selectively recharged when the motors are actively operated as generators, z. By absorbing energy during a regenerative braking event.

The motor torque of one or both drive motors 12 and 14 gets to their respective motor shafts 120 and 140 each of which is transmitted with different elements from one or more planetary gear sets 30 of the transmission 18 connected is. Several brake and / or rotary joints 32 are also in gear 18 provided a torque from the motors 12 and or 14 and / or from a crankshaft 13 the engine 16 selectively to an output element 33 to transmit the transmission. The starting element 33 of the transmission 18 is finally through an axis 36 and a final gearbox 35 with the drive wheels 34 of the vehicle 10 connected.

The vehicle 10 contains the TPIM 20 which is a rectifier / inverter and controller configured to provide motor control commands 41 from the controller 22 to recieve. The controller 22 can with any of the drive motors 12 and 14 be electrically connected and be designed to raw speed data 40 from different speed sensors 43 to receive, as needed, anywhere in the vehicle 10 are positioned, for. B. on the axis 36 , the motor shafts 120 . 140 , the input element 21 etc. The controller 22 controls the engine speed, mode of operation, and power flow to and from the engines and to other electrical equipment on board the vehicle 10 ,

The controller 22 uses the control logic 100 to a torque output from the drive motors 12 and 14 through the transmission 18 to the axis 36 to control automatically. The control logic 100 automatically combines the control of damping torque and speed of the motors 12 . 14 , This contributes to a perceived discontinuity in the applied torque during a change in shifting states of the transmission 18 to prevent. Consequently, the speed control is combined with the damping control as part of an integrated system, and from using error values of speed integrators for the input speed and clutch speed, a fundamental change occurs in the use of error values of speed integrators for the motors 12 and 14 in a closed loop. This eliminates a stationary error in engine speeds in an approach, now with reference to FIGS 2 and 3 is described.

Regarding 2 contains the control logic 100 different logic blocks 50 . 54 . 56 and 58 , A block 50 for a desired dynamics receives a set of desired goals (arrow 42 ), such as an actual engine torque, a desired axle torque, a wheel speed, and a desired input speed and clutch speeds for the transmission 18 , These values can be determined based on operator input, e.g. A force applied to an accelerator pedal, a position of a transmission gear selector lever, a status of a vehicle brake system, a speed control setting, and / or other suitable operator inputs. The entrances to the block 50 for a desired dynamics are used to set a desired operating condition for each of the torque-generating devices on board the vehicle 10 using reference parameters or signals 44 for the different operating conditions.

The block 50 for a desired dynamic determines reference signals (arrow 44 ) and passes the measured speed (arrow 46 ) further. The reference signals (arrow 44 ) may be a calibrated reference value for a damper torque, ie, input clutch 11 , for an axle torque, for speeds for the drive motors 12 and 14 , included for a transmission output speed and for engine speed. The measured speeds (arrow 46 ) can speed from both engines 12 and 14 contain.

The reference signals (arrow 44 ) and the measured speeds (arrow 46 ) are connected to an engine speed torque Control block (MST control block) 54 and a motor damping torque control block (MDT control block) 56 forwarded. On the MST control block 54 Referring to this block, it calculates speed control torque signals 65 . 165 for the respective engines 12 and 14 , These values are sent to different sum nodes as shown 75 and 76 forwarded. At the same time, the MDT control block calculates 56 separately damping torque signals 60 . 160 for the respective engines 12 and 14 , The speed control torque signal 65 arrives at the same sum node as the damping torque signal 160 ie at the node 75 , so that the torque signal for the speed control of the motor 12 with the torque signal for the damping torque of the engine 14 combined. The speed control torque signal comes in the same way 165 at the same summing node as the damping torque signal 60 ie the node 76 , so that the torque signal for the speed control of the motor 14 with the torque signal for the damping torque of the engine 12 combined.

In the box 95 with dashed line will also be torque commands 70 and 170 with open loop into the respective summation nodes 75 and 76 entered. The outputs of the nodes 75 and 76 are a total engine control torque 80 for the engine 12 and a total engine control torque 180 for the engine 14 , These torque values are sent to a block 58 forwarded for a dynamic model of the driveline. The torque values 80 and 180 can be from the controller 22 used as needed in conjunction with other dynamic driveline control operations to provide vibration along the driveline of the vehicle 10 to control and manage. In the block 58 for a dynamic model of the driveline, a set of system torques is also fed in, e.g. As the engine torque, the clutch torque, the brake torque, an accessory load, a road load, etc.

The block 58 for a model of the final drive has various outputs, which are characterized by the various dynamic forces acting on the final drive, and known individual properties of the final drive, for. B. mass and inertial forces are determinable. Thus, the controller calculates 22 or otherwise determines various required feedback parameters that include an estimated damper torque 90 from the input clutch 11 (please refer 1 ), an estimated axle torque 92 and estimated or measured speed data 40 for example for the wheels 34 , the drive motors 12 and 14 , the transmission output element 33 and the engine 16 include. The in the block 58 Entering and exiting values may be subjected to required analog to digital or digital to analog conversion, filtering, calibration, and other manipulations needed to obtain a representative signal. The estimated damper torque 90 , the estimated axle torque 92 and the estimated or measured speed data 40 are sent to the MDT control block 56 as additional inputs for this block, and the estimated or measured speed data 40 will also be at the block 50 for a desired dynamics attributed.

In one embodiment, the controller may 22 a first matrix may be formed, which comprises a one-dimensional matrix or a vector, which is a subset of the reference signals 44 contains. Using the estimated damper torque 90 , the estimated axle torque 92 and the estimated or measured speed 40 a second matrix can be formed. The second matrix may then be multiplied by a gain matrix to compute a feedback matrix.

An individual gain matrix may be determined for each transmission operating mode. The gain matrices may be determined off-line and stored as calibration values for use, as mentioned below. The first matrix can be in the MDT control block 56 are input to the reference signals 44 to the MDT control block. In the same way, the feedback matrix may feedback the estimated damper torque 90 , the feedback of the estimated axle torque 92 and the feedback of the estimated or measured speed 40 to the MDT control block 56 to transfer. The MDT control block 56 can then solve several equations simultaneously, z. Using template algebra. The solved equations can be used to determine torques associated with the drive motors 12 and 14 based on the operating state parameters contained in the first matrix and the feedback matrix.

Regarding 3 FIG. 10 is a flowchart generally illustrating the aspect of gain calculation and multiplication of the control logic 100 , in the 2 shown and described above. The controller 22 calculates the speed error of the drive motors 12 and 14 at step 102 respectively. 106 , This can be done at the error calculation block 54 from 2 be done. The speed error of the steps 102 and 106 are then to respective multiplication nodes 110 and 112 forwarded.

At step 104 the controller calculates 22 the gain for the drive motor 14 used to control the drive motor 12 is needed. This gain value is then sent to the node 110 forwarded where he was with the error value of step 102 is multiplied. The output of the node 110 gets to the node 114 forwarded.

step 108 calculates the gain value for the drive motor 12 which is needed for the anticancer motor 14 to control. This gain value will be at the node 112 where it passes with the engine speed error value of step 106 is multiplied. The output of the node 112 gets to the node 114 forwarded. At nodes 116 will be the output values from the nodes 110 and 112 added together and the resulting value can be determined at step 116 used to calculate the engine torque, that for the drive motor 12 is needed. A similar process can be used to calculate the engine torque for the drive motor 14 is needed.

As in 3 is shown, the gains are multiplied so that the calculated control torques and engine speeds are fully integrated. This avoids a discontinuity in the control torque as mentioned above. Error in engine speed for the drive motors 12 and 14 are used to calculate the engine control torques rather than, for example, using the transmission input speed and / or the clutch slip speed. The result is an improved vehicle ride quality in which engine speed errors are controlled to zero, resulting in gear shifts or gearshift changes of the transmission 18 be optimized.

Although the best modes for carrying out the invention have been described in detail, those skilled in the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.

Claims (10)

Vehicle that includes: a drive rotor; a driven by the drive motor gear; and a controller configured to automatically combine a damping torque control command with an engine speed control command to thereby prevent a discontinuity in engine torque applied by the drive motor during a change of shifting states of the transmission. The vehicle of claim 1, wherein the drive motor includes first and second drive motors, and wherein the controller automatically combines a damping torque control command with an engine speed control command for each of the first and second drive motors. The vehicle of claim 1, wherein the damping control torque provides a proportional gain for the engine speed control torque. The vehicle of claim 1, wherein the controller is configured to automatically combine the damping torque control with the engine speed control, partially by calculating an error value in the speed of the drive motor and then using the calculated error value to determine a required damping torque to provide the damping control torque , The vehicle of claim 4, wherein the drive motor includes first and second drive motors and wherein the controller is configured to multiply the calculated error value for the first drive motor by a gain value of the second drive motor before determining the required damping torque. The vehicle of claim 5, further comprising an engine, an axle, drive wheels and a clutch of the transmission, the controller configured to: receive a set of desired targets including an actual engine torque of the engine, a desired axle torque of the axle, wheel speeds of the drive wheels, a desired input speed of the transmission, and / or a desired clutch speed of the clutch; to calculate a desired operating condition for each of the drive motors; and use the controller to output a set of reference signals for the desired operating state. The vehicle of claim 6, further comprising an input clutch between the engine and the transmission, the reference signals including a calibrated reference value for a damper torque from the input clutch. The vehicle of claim 1, wherein the controller is configured to: calculate a speed control torque signal for each of the motors using an engine speed torque control (MST) control block; calculate a motor damping torque signal for each of the motors using a motor damping torque control block (MDT control block); and combine the speed control torque signal and the engine damping torque signal to produce a total engine control torque for each of the engines. The vehicle of claim 8, wherein the controller is configured to: to process the engine control total torque for the engine through a model of the vehicle driveline to thereby generate an estimated damper torque for an input clutch of the vehicle, an estimated axle torque for an axle of the vehicle, and an estimated wheel speed for the wheels of the vehicle, and feeding the estimated damper torque, the estimated axle torque, and the estimated wheel speed as inputs to the MDT control block back to the MDT control block. A method for minimizing driveline perturbations in a vehicle having a controller and a transmission driven by a first and a second drive motor, the method comprising: a change in switching states of the transmission is detected; and a damping control torque is automatically combined with a closed loop engine speed control torque by the controller for each of the first and second drive motors to prevent a noticeable discontinuity in a motor torque applied by the first and second drive motors during the change in the shift state; wherein automatically combining a damping control torque includes calculating an error value in the rotational speed of the at least one drive motor, and then using the calculated error value to determine a required damping torque to provide the damping control torque.

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