Control system for suppressing vibration of output shaft, vehicle and transmission comprising same, and method thereof

Abstract

A vehicle, a transmission, and a method of suppressing vibration at an output shaft of the transmission are disclosed. A vehicle includes a chassis, a plurality of wheels coupled to the chassis, and a powertrain mounted on the chassis, the powertrain including a transmission. The transmission includes an input shaft receiving torque from a drive unit, an output shaft transmitting torque to a load, at least one torque transmitting mechanism coupled between the input shaft and the output shaft, and a control system having an output speed sensor and a controller, the output speed sensor provides an input signal indicative of a rotational speed of the output shaft, and the controller is communicatively coupled to the output speed sensor.

Description

Technical Field

[0001] The present invention relates generally to control systems for transmissions and, more particularly, to a transmission control system including a sensor for measuring rotational speed of a transmission output shaft. Background Art

[0002] In some configurations, fluctuations in torque output from the transmission output shaft may cause the output shaft to vibrate. This vibration may be perceived by the vehicle operator as judder during vehicle operation. Systems, devices, and / or methods for reducing judder that avoid the drawbacks associated with previous configurations remain an area of ​​interest. Summary of the Invention

[0003] The present invention may include one or more of the following features and combinations thereof.

[0004] According to one aspect of the present invention, a vehicle may include a chassis, a plurality of wheels coupled to the chassis, and a powertrain mounted on the chassis. The powertrain may include a transmission. The transmission may include an input shaft for receiving torque from a drive unit, an output shaft for transmitting torque to a load, at least one torque-transmitting mechanism coupled between the input shaft and the output shaft, and a control system. The control system may include an output speed sensor and a controller, the output speed sensor providing an input signal representing a rotational speed of the output shaft, the controller communicatively coupled to the output speed sensor. The controller may include a processor and a memory having instructions stored therein. The instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft based on the input signal, determine a difference between the monitored rotational speed of the output shaft and a reference rotational speed, determine an adjustment to an upcoming clutch pressure to be applied to the at least one torque-transmitting mechanism based on the difference, determine a compensated clutch pressure to be applied to the at least one torque-transmitting mechanism based on the adjustment, and apply the compensated clutch pressure to the at least one torque-transmitting mechanism to suppress vibration at the output shaft during vehicle use.

[0005] In some embodiments, the vehicle may not have a mechanical shock absorber coupled to the output shaft. The instructions are executable by the processor to cause the processor to apply the compensated clutch pressure to the at least one torque-transmitting mechanism to dampen vibrations at the output shaft during a transition from one operating mode of the transmission to another operating mode of the transmission.

[0006] In some embodiments, to determine the difference between the monitored speed of the output shaft and the reference speed, the instructions are executable by the processor to cause the processor to receive the input signal from the output speed sensor, retrieve the reference speed of the output shaft, compare the input signal to the reference speed, and determine the difference based on the comparison. To determine the adjustment to the oncoming clutch pressure, the instructions are executable by the processor to cause the processor to calculate the adjustment based on the difference between the monitored speed of the output shaft and the reference speed, and convert the calculated adjustment into a desired clutch pressure command. To determine the compensated clutch pressure, the instructions are executable by the processor to cause the processor to receive an oncoming base clutch pressure command, receive a desired clutch pressure command, and determine the compensated clutch pressure based on the oncoming base clutch pressure command and the desired clutch pressure command.

[0007] In some embodiments, to monitor the rotational speed of the output shaft, the instructions may be executed by the processor to cause the processor to monitor the rotational speed of the output shaft in response to the output speed sensor initially detecting a rotational target disposed proximate to the output shaft. The rotational target may be any one of a plurality of teeth formed on the output shaft. Furthermore, in some embodiments, the output speed sensor's initial detection of the rotational target may offset hysteresis in hydraulic actuation of the at least one torque-transmitting mechanism.

[0008] According to another aspect of the present invention, a transmission may include an input shaft for receiving torque from a drive unit, an output shaft for transmitting torque to a load, at least one torque-transmitting mechanism coupled between the input shaft and the output shaft, and a control system. The control system may include an output speed sensor and a controller, the output speed sensor providing an input signal representing a rotational speed of the output shaft, the controller being communicatively coupled to the output speed sensor. The controller may include a processor and a memory having instructions stored therein. The instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft based on the input signal, determine a difference between the monitored rotational speed of the output shaft and a reference rotational speed, and determine an adjustment to an upcoming clutch pressure to be applied to the at least one torque-transmitting mechanism based on the difference. The transmission may not have a mechanical damper coupled to the output shaft.

[0009] In some embodiments, to determine the adjustment to the oncoming clutch pressure, the instructions are executable by the processor to cause the processor to calculate the adjustment based on the difference between the monitored speed of the output shaft and the reference speed, and convert the calculated adjustment into a desired clutch pressure command. Furthermore, in some embodiments, to determine the difference between the monitored speed of the output shaft and the reference speed, the instructions are executable by the processor to cause the processor to receive the input signal from the output speed sensor, retrieve the reference speed of the output shaft, compare the input signal to the reference speed, and determine the difference based on a result of the comparison.

[0010] In some embodiments, to monitor the rotational speed of the output shaft, the instructions may be executed by the processor to cause the processor to monitor the rotational speed of the output shaft in response to the output speed sensor initially detecting any one of a plurality of teeth disposed proximate to the output shaft. The output speed sensor initially detecting any one of the plurality of teeth may offset a lag in hydraulic actuation of the at least one torque-transmitting mechanism.

[0011] In some embodiments, the instructions are executable by the processor to cause the processor to determine a compensated clutch pressure to be applied to the at least one torque-transmitting mechanism based on the adjustment amount. The instructions are executable by the processor to cause the processor to apply the compensated clutch pressure to the at least one torque-transmitting mechanism to suppress vibration at the output shaft during use of the transmission.

[0012] According to another aspect of the present invention, a method for suppressing vibration at an output shaft of a transmission may include: monitoring, by a controller, a rotational speed of the output shaft based on an input signal provided by an output speed sensor; determining, by the controller, a difference between the monitored rotational speed and a reference rotational speed of the output shaft; determining, by the controller, an adjustment amount for an upcoming clutch pressure to be applied to at least one torque transmitting mechanism of the transmission based on the difference; determining, by the controller, a compensated clutch pressure to be applied to the at least one torque transmitting mechanism based on the adjustment amount; and applying, by the controller, the compensated clutch pressure to the at least one torque transmitting mechanism to suppress vibration at the output shaft during use of the transmission.

[0013] In some embodiments, applying the compensated clutch pressure to the at least one torque-transmitting mechanism may include damping vibrations at the output shaft without using a mechanical damper coupled to the output shaft. Furthermore, in some embodiments, monitoring the rotational speed of the output shaft may include monitoring the rotational speed of the output shaft in response to initial detection by the output speed sensor of any one of a plurality of teeth disposed proximate the output shaft. Initial detection by the output speed sensor of any one of the plurality of teeth may offset hysteresis in hydraulic actuation of the at least one torque-transmitting mechanism.

[0014] These and other features of the present invention will become more apparent from the following description of illustrative embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention described herein is illustrated by way of example in the accompanying drawings, and is not intended to be limiting. For simplicity and clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Furthermore, where appropriate, reference numerals have been repeated in the drawings to indicate corresponding or similar elements.

[0016] Figure 1 A partial schematic diagram of a vehicle's drive system;

[0017] Figure 2 A partial schematic diagram of a vehicle's power system;

[0018] Figure 3 To include in Figure 1 Drive system or Figure 2 A schematic diagram of a transmission control system in a transmission of a power system;

[0019] Figure 4 To be included in Figure 3 A schematic diagram of multiple modules in a controller of the control system shown;

[0020] Figure 5 To suppress the vibration at the transmission output shaft Figure 3 a schematic depiction of the various inputs provided to, and the functions performed by, the controller of the illustrated control system;

[0021] Figure 6 A simplified flow chart of a method for suppressing vibrations at a transmission output shaft;

[0022] Figure 7 For Figure 4 A simplified flow chart of a method performed by an output speed processing module of a controller is illustrated in FIG.

[0023] Figure 8 For Figure 4 A simplified flow chart of a method performed by an oncoming clutch pressure adjustment determination module of a controller is illustrated in FIG.

[0024] Figure 9 For Figure 4 A simplified flow chart of a method performed by a clutch pressure compensation module of a controller is illustrated in FIG.

[0025] Figure 10A is a graphical representation of vibration at the transmission output shaft without any damping or judder relief; and

[0026] Figure 10B is a graphical representation of vibration at the transmission output shaft with damping / judder mitigation. DETAILED DESCRIPTION

[0027] While the present invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that there is no intention to limit the present invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present invention and the appended claims.

[0028] References in the specification to "one embodiment," "an embodiment," "an illustrative embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but that each embodiment may or may not include that particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described. Furthermore, it should be understood that items included in a list of the form "at least one of A, B, and C" may mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C). Similarly, items listed in the form "at least one of A, B, or C" may mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).

[0029] In the accompanying drawings, for ease of description, some structural or method features, such as those representing devices, modules, instruction blocks, and data elements, may be shown in a particular arrangement and / or order. However, it should be understood that such a particular arrangement and / or order may not be required. On the contrary, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. In addition, the inclusion of a structural or method feature in a particular drawing does not imply that such feature is required in all embodiments, and in some embodiments, the feature may not be included or may be combined with other features.

[0030] In certain embodiments, the schematic elements for representing method step block can be manually performed by the user.In other embodiments, these schematic elements can use the machine-readable instruction (such as software or firmware application, program, function, module, routine, process, process, plug-in, applet, widget, code snippet and / or other) of any suitable form to automatically implement, and each such instruction can use any suitable programming language, library, application programming interface (API) and / or other software development tools to implement.For example, in certain embodiments, schematic elements can use Java, C++ and / or other programming languages ​​to implement.Similarly, the schematic elements for representing data or information can use any suitable electronic arrangement or structure (such as register, data storage, table, record, array, index, hash, mapping, tree, list, graph, file (file of any file type), folder, directory, database and / or other) to implement.

[0031] In addition, in the accompanying drawings, when using connecting elements such as solid or dotted lines or arrows to illustrate the connection, relationship or association between two or more other schematic elements, not showing any such connecting elements does not mean that there is no connection, relationship or association. In other words, some connections, relationships or associations between elements may not be shown in the accompanying drawings to avoid blurring the present disclosure. In addition, for ease of explanation, a single connecting element may be used to represent multiple connections, relationships or associations between elements. For example, when connecting elements represent the communication of signals, data or instructions, it will be understood by those skilled in the art that, as needed, such elements may represent one or more signal paths (e.g., buses) to achieve communication.

[0032] In some vehicle configurations, rotational power may be transmitted from the transmission output shaft to a vehicle driveline that lacks one or more structures (e.g., mechanical shock absorbers, struts, suspension devices, etc.) to dampen vibrations at the output shaft caused by torque output fluctuations. Additionally, in some vehicle configurations, rotational power may be transmitted from the transmission output shaft to an underdamped vehicle driveline such that the driveline experiences vibrations despite the provision of one or more damping devices. In either case, for purposes of the present invention, a vehicle driveline that experiences vibrations due to transmission output shaft torque fluctuations may be referred to as a compliant driveline.

[0033] Vibrations transmitted to the flexible driveline may be perceived by the vehicle operator as judder. Judder may be particularly noticeable to the vehicle operator during a shift or transition from one operating mode of the transmission to another. For example, in some configurations, judder may be typically felt during a shift or transition from a first forward gear or gear ratio of the transmission to a second forward gear or gear ratio of the transmission. Of course, it should be understood that the perceptibility of the judder effect may vary depending on the specific vehicle and the specific gear or gear ratio of the vehicle's transmission. Regardless, in many cases, judder may be detrimental to ride quality, shift time, and / or shift quality.

[0034] The present invention contemplates systems, devices, and / or methods for damping vibrations at the output shaft of a transmission to reduce judder, thereby improving ride quality, shift time, and / or shift quality. In an illustrative embodiment, a vehicle (e.g., Figure 2 ) includes a chassis or main frame 202, wheels 204 coupled to the chassis 202, and a power system 210 mounted on the chassis 202. In the illustrative embodiment, the power system 210 is embodied as or otherwise includes a collection of devices that are capable of cooperatively generating and transmitting rotational power to the wheels 204 of the vehicle 200 to propel the vehicle 200 during use. In some embodiments, the power system 210 is mounted on the chassis 202 transverse to a longitudinal axis LA along which the chassis 202 extends. In those embodiments, the power system 210 is arranged transverse to the direction of travel TD of the vehicle 200, and the power system 210 can be said to have a transverse mounting arrangement relative to the chassis 202. However, in other embodiments, the power system 210 can be mounted on the chassis 202 in another suitable manner.

[0035] In any case, in the illustrative embodiment, the powertrain 210 includes a transmission, such as, for example Figure 2 The transmission 230 and / or Figure 1 The transmission 120 is shown. Figure 1The transmission 120 includes an input shaft 122 that receives torque from a drive unit (e.g., drive unit 102), an output shaft 124 that transmits torque to a load (e.g., a wheel axle 132 and wheels 134A and 134B mounted thereon), and at least one torque-transmitting mechanism 142 (shown in phantom) coupled between the input shaft 122 and the output shaft 124. In addition, the transmission 120 and / or the transmission 230 includes a control system 300 (see FIG. 1 ). Figure 3 ), the control system having an output speed sensor 150 providing an input signal representing the rotational speed of the output shaft 124 and a controller 302 communicatively coupled to the output speed sensor 150,

[0036] The illustrative controller 302 includes a processor 304 and a memory 306 having instructions stored therein. In the illustrative embodiment, as Figure 6 As best shown in FIG, instructions are executable by the processor 304 to cause the processor 304 to monitor the rotational speed of the output shaft 124 based on an input signal provided by the output speed sensor 150 (see block 602), determine a difference between the monitored rotational speed of the output shaft 124 and a reference rotational speed (see block 604), determine an adjustment to an upcoming clutch pressure to be applied to at least one torque-transmitting mechanism 142 based on the difference (see block 606), determine a compensated clutch pressure to be applied to the at least one torque-transmitting mechanism 142 based on the adjustment (see block 608), and apply the compensated clutch pressure to the at least one torque-transmitting mechanism 142 to dampen vibrations at the output shaft 124 during use of the vehicle 200 (see block 610). In this manner, the illustrative control system 300 employs a computer-implemented model to dampen vibrations at the output shaft 124 without using a damping device (e.g., a mechanical damper) coupled to the output shaft 124.

[0037] In some configurations, providing mechanical shock absorbers may be sufficient to suppress vibrations associated with shudder or other powertrain disturbances other than shudder. In contrast, in at least some embodiments, vehicle 200 does not have mechanical shock absorbers coupled to output shaft 124. Illustrative control system 300 is designed to suppress vibrations at output shaft 124 associated with shudder or other powertrain disturbances other than shudder in a manner similar to mechanical shock absorbers.

[0038] Reference Figure 1The illustrative drive system 100 is suitable for use with or otherwise incorporated into one or more vehicles employed in various applications. In some embodiments, the drive system 100 may be suitable for use with or otherwise incorporated into fire and rescue vehicles, garbage trucks, coaches, RVs and motorhomes, municipal and / or service vehicles, agricultural vehicles, mining vehicles, specialty vehicles, energy vehicles, defense vehicles, port service vehicles, construction vehicles, and transit and / or buses, to name a few. Moreover, in some embodiments, the drive system 100 may be suitable for use with or otherwise incorporated into tractors, front-end loaders, scrapers, cutting and shredding machines, hay and forage equipment, planting equipment, seeding equipment, sprayers and applicators, tillage equipment, utility vehicles, mowers, dump trucks, backhoes, track loaders, crawler loaders, bulldozers, excavators, motor graders, skid steers, tractor loaders, wheel loaders, rakes, aerators, skidders, bunchers, conveyors, harvesters, swing machines, toggle loaders, diesel engines, axles, planetary gear transmissions, pump transmissions, transmissions, generators, and marine engines, among other suitable equipment.

[0039] In the illustrative embodiment, the drive unit 102 is embodied as or otherwise includes any device capable of generating rotational power to drive other components of the drive system 100 (e.g., the torque converter 108 and the transmission 120) during use. In some embodiments, the drive unit 102 may be embodied as or otherwise include an internal combustion engine, a diesel engine, an electric motor, or other power generation device. In any case, the drive unit 102 is configured to rotatably drive the output shaft 104, which is coupled to the input shaft of the torque converter 108 or the pump shaft 106.

[0040] The input shaft or pump shaft 106 of the illustrative torque converter 108 is coupled to an impeller or pump 110, which is rotationally driven by the output shaft 104 of the drive unit 102. The torque converter 108 also includes a turbine 112 coupled to a turbine shaft 114. In the illustrative embodiment, the turbine shaft 114 is coupled to or integral with an input shaft 122 of the transmission 120.

[0041] The illustrative torque converter 108 also includes an interlocking clutch 136 connected between the pump 110 and the turbine 112 of the torque converter 108. The torque converter 108 can be operated in a so-called "torque converter" mode under certain operating conditions, such as during vehicle startup, low-speed conditions, and certain gear shift conditions. In the torque converter mode, the interlocking clutch 136 is disengaged, the pump 110 rotates at the speed of the drive unit output shaft 104, and the turbine 112 is rotationally actuated by the pump 110 via a fluid (not shown) between the pump 110 and the turbine 112. In this operating mode, torque multiplication occurs through the fluid coupling, so that the turbine shaft 114 is driven by a torque greater than the torque provided by the drive unit 102. During other operating conditions, such as when torque multiplication is not required, the torque converter 108 can alternatively be operated in a so-called "interlocking" mode. In interlock mode, the interlock clutch 136 is engaged, thereby grounding the pump 110 directly to the turbine 112 , such that the drive unit output shaft 104 is directly coupled to the input shaft 124 of the transmission 118 .

[0042] In the illustrative embodiment, the transmission 120 includes an internal pump 118 that is configured to pressurize and / or distribute fluid to one or more fluid (e.g., hydraulic fluid) circuits. In some embodiments, for example, the pump 118 can be configured to pressurize and / or distribute fluid to a main circuit, a lubrication circuit, an electro-hydraulic control circuit, and / or any other circuit incorporated into the electro-hydraulic system 138. It should be understood that in some embodiments, the pump 118 can be driven by a shaft 116 that is coupled to the output shaft 104 of the drive unit 102. In this arrangement, the drive unit 102 can transmit torque to the shaft 116 for driving the pump 118 and building up hydraulic pressure within the various circuits of the transmission 120.

[0043] The illustrative transmission 120 includes a gear system 126 coupled between an input shaft 122 and an output shaft 124. It should be understood that the gear system 126 can include one or more gear arrangements (e.g., a planetary gear arrangement, an epicyclic transmission arrangement, etc.) that provide or are otherwise associated with one or more gear ratios. When used in conjunction with the electro-hydraulic system 138 under the control of the control system 300, the gear system 126 can provide or otherwise be associated with one or more operating ranges selected by the operator.

[0044] The output shaft 124 of the transmission 120 is illustratively coupled to, or integral with, a propeller shaft 128. The propeller shaft 128 is coupled to a universal joint 130, which is coupled to and rotatably drives an axle 132 and wheels 134 and 136. In this arrangement, when the drive system 100 is in use, the output shaft 124 drives the wheels 134 and 136 via the propeller shaft 128, the universal joint 130, and the axle 132.

[0045] The illustrative transmission includes an electro-hydraulic system 138 that is fluidly coupled to the gear system 126 via a plurality (i.e., J) of fluid paths 1401-140J, where J may be any positive integer. In the illustrative embodiment, at least one torque-transmitting mechanism 142 may be included in the electro-hydraulic system 138. The electro-hydraulic system 138 is configured to receive control signals provided by various electro-hydraulic control devices 310, such as one or more sensors 312 and one or more flow and / or pressure control devices 314 (see FIG. 1 ). Figure 3 In response to these control signals, and under the control of the control system 300, the electro-hydraulic system 138 selectively causes fluid to flow through one or more fluid paths 1401-140J to control the operation (e.g., engagement and disengagement) of one or more friction devices (e.g., at least one torque-transmitting mechanism 142) included in or otherwise adapted for use with the gear system 126.

[0046] Of course, it should be understood that the at least one torque-transmitting mechanism 142 may include, but is not limited to, one or more brake devices, one or more torque-transmitting devices, and the like. Generally, the operation (e.g., engagement and disengagement) of the at least one torque-transmitting mechanism 142 is controlled by selectively controlling the friction applied by or otherwise associated with each of the one or more torque-transmitting mechanisms 142, such as, for example, by controlling the fluid pressure applied to each mechanism. In the illustrative embodiment, which is not intended to be limiting in any way, the electro-hydraulic system 138 may be coupled to or otherwise adapted for use with one or more brakes 320. Similar to the torque-transmitting mechanism(s) 142, each of the one or more brakes 320 may be controllably engaged and disengaged via fluid pressure supplied by the electro-hydraulic system 138. In any case, changing or shifting between various gears of the transmission 120 is accomplished by selectively controlling the friction devices 142, 320 by controlling the fluid pressure within the plurality of fluid paths 1401-140J.

[0047] exist Figure 1In the illustrative system 100 shown, the torque converter 108 and the transmission 120 include a plurality of sensors configured to generate sensor signals indicative of one or more operating conditions of the torque converter 108 and the transmission 120, respectively. For example, the torque converter 108 illustratively includes a speed sensor 146 configured to generate a speed signal corresponding to the rotational speed of the pump shaft 106, which rotates at the same speed as the output shaft 104 of the drive unit 102 during use of the drive system 100. The speed sensor 146 is electrically connected to a pump speed input (i.e., PS) port of the controller 302 via a signal path 152, and the controller 302 is operable to process the speed signal generated by the speed sensor 146 to determine the rotational speed of the pump shaft 106 / drive unit output shaft 104.

[0048] In the illustrative system 100, the transmission 120 includes a speed sensor 148 configured to generate a speed signal corresponding to the rotational speed of the transmission input shaft 122, which, during use of the system 100, rotates at the same speed as the turbine shaft 114 of the torque converter 108. The input shaft 122 of the transmission 120 may be directly coupled to the turbine shaft 114 or integrally formed therewith. Of course, it should be understood that the speed sensor 148 may alternatively be configured to generate a speed signal corresponding to the rotational speed of the turbine shaft 114. Regardless, the speed sensor 148 is electrically connected to a transmission input shaft speed input (i.e., TIS) port of the controller 302 via a signal path 154, and the controller 302 is operable to process the speed signal generated by the speed sensor 148 to determine the rotational speed of the turbine shaft 114 / transmission input shaft 124.

[0049] Furthermore, in the illustrative system 100, the transmission 120 includes a speed sensor 150 that is configured to generate a speed signal corresponding to the rotational speed and direction of the output shaft 124 of the transmission 120. The speed sensor 150 is electrically connected to a transmission output shaft speed input (i.e., TOS) port of the controller 302 via a signal path 156. The controller 302 is configured to process the speed signal generated by the speed sensor 150 to determine the rotational speed of the transmission output shaft 124.

[0050] In the illustrative embodiment, the electro-hydraulic system 138 includes one or more actuators configured to control various operations within the transmission 120. For example, the electro-hydraulic system 138 described herein illustratively includes a plurality of actuators (e.g., which may be included in the device 314) electrically connected to a plurality (i.e., J) of control output ports CP1-CPJ of the controller 302 via a corresponding number of signal paths 721-72J, where J may be any positive integer as described above. Each actuator may receive a corresponding one of the control signals CP1-CPJ generated by the controller 302 via a corresponding one of the signal paths 721-72J. In response, each actuator may control the friction applied by each friction device by controlling the fluid pressure within one or more corresponding fluid channels 1401-140J, thereby controlling the operation of one or more corresponding friction devices based on information provided by the respective speed sensors 146, 148, and / or 150 during use of the system 100.

[0051] In the illustrative embodiment, system 100 includes a drive unit controller 160 having input / output (I / O) ports electrically coupled to drive unit 102 via a plurality (i.e., K) of signal paths 162, where K can be any positive integer. Drive unit controller 160 is operable to control and manage the overall operation of drive unit 102. Drive unit controller 160 includes a communication port (i.e., COM) electrically connected to a similar communication port (i.e., COM) of controller 302 via a plurality (i.e., L) of signal paths 164, where L can be any positive integer. It should be understood that one or more signal paths 164 may be collectively referred to as a data link. Generally, drive unit controller 160 and transmission controller 302 are operable to share information via one or more signal paths 164. For example, in one embodiment, drive unit controller 160 and transmission controller 302 are operable to share information via one or more signal paths 164 in the form of one or more messages compliant with the Society of Automotive Engineers (SAE) J-1939 communication protocol. Of course, it should be understood that the present disclosure contemplates other embodiments in which the drive unit controller 160 and the transmission controller 302 are operable to share information via one or more signal paths 164 in accordance with one or more other communication protocols (e.g., selected from conventional data buses such as a J1587 data bus, a J1939 data bus, an IESCAN data bus, a GMLAN, a Mercedes PT-CAN).

[0052] Reference Figure 2, power system 210 includes a drive unit 212 (shown in phantom) that generates rotational power and a drive axle 220 coupled to drive unit 212 to receive the rotational power and transmit the rotational power to wheels 204. At least in some embodiments, drive unit 212 can be the same or substantially the same as drive unit 102. In some embodiments, vehicle 200 is embodied as or includes an electric vehicle. In one example, vehicle 200 is embodied as or otherwise includes a medium- or heavy-duty electric truck or an electric bus, and power system 210 is used to replace one or more conventional power systems associated with one or more internal combustion engine configurations.

[0053] The illustrative drive axle 220 is embodied as or includes any collection of devices capable of receiving rotational power from the drive unit 212 and transmitting the rotational power to the wheels 204. In the illustrative embodiment, the drive axle 220 includes a transmission 230, a differential 240 coupled to the transmission 230, and a differential 240 coupled to the transmission 230. Figure 2 and an axle assembly 250 coupled to the differential 240 (shown in dashed lines in FIG. Figure 2 In at least some embodiments, transmission 230 may be the same or substantially the same as transmission 120.

[0054] Reference Figure 3 In the illustrative embodiment, the transmission control system 300 includes the sensors 146, 148, 150, a controller 302, one or more operator input devices 308, one or more electro-hydraulic control devices 310, at least one torque-transmitting mechanism 142, brake(s) 320, and an instrument panel 326. Each of the devices 146, 148, 150, 308, 310, 142, 320, 326 is communicatively coupled to the controller 302. In some embodiments, the controller 302 can be communicatively coupled to a sensor 316 and / or control device 318 for the at least one torque-transmitting mechanism 142 and a sensor 322 and / or control device 324 for the brake(s) 320.

[0055] The processor 304 of the illustrative controller 302 may be embodied as or include any type of processor, controller, or other computing circuitry capable of performing various tasks, such as computing functions and / or controlling the functions of the transmissions 120, 230. For example, the processor 304 may be embodied as (one or more) single-core or multi-core processors, microcontrollers, or other processors or processing / control circuitry. In some embodiments, the processor 304 may be embodied as, include, or otherwise coupled to an FPGA, an application-specific integrated circuit (ASIC), reconfigurable hardware or hardware circuitry, or other specialized hardware to facilitate the execution of the functions described herein. Furthermore, in some embodiments, the processor 304 may be embodied as or include a high-power processor, an accelerated coprocessor, or a memory controller. In other embodiments, the processor 304 may include more than one processor, controller, or computing circuitry.

[0056] The memory device 306 of the illustrative controller 302 can be embodied as any type of volatile memory (e.g., dynamic random access memory (DRAM), etc.) or non-volatile memory capable of storing data therein. Volatile memory can be embodied as a storage medium that requires power to maintain the state of the data stored by the medium. Non-limiting examples of volatile memory can include various types of random access memory (RAM), such as dynamic random access memory (DRAM) or static random access memory (SRAM). One specific type of DRAM that can be used in the memory module is synchronous dynamic random access memory (SDRAM). In certain embodiments, the DRAM of the memory component may conform to a standard promulgated by JEDEC, such as JESD79F for DDR SDRAM, JESD79-2F for DDR2 SDRAM, JESD79-3F for DDR3 SDRAM, JESD79-4A for DDR4 SDRAM, JESD209 for Low Power DDR (LPDDR), JESD209-2 for LPDDR2, JESD209-3 for LPDDR3, and JESD209-4 for LPDDR4 (these standards are available at www.jedec.org). Such a standard (and similar standards) may be referred to as a DDR-based standard, and a communication interface of a memory device that implements such a standard may be referred to as a DDR-based interface.

[0057] In some embodiments, memory device 306 may be embodied as a block-addressable memory, such as those based on NAND or NOR technology. Memory device 306 may also include next-generation non-volatile devices, such as three-dimensional cross-point memory devices (e.g., Intel 3D XPoint TMMemory), or other byte-addressable, in-place write-able non-volatile memory devices. In some embodiments, the memory device 306 may be embodied as or may otherwise include chalcogenide glass, multi-threshold NAND flash memory, NOR flash memory, single-level or multi-level phase change memory (PCM), resistive memory, nanowire memory, ferroelectric transistor random access memory (FeTRAM), antiferroelectric memory, magnetoresistive random access memory (MRAM) combined with memristor technology, resistive memory including metal oxide-based, oxygen vacancy-based, and conductive bridge random access memory (CB-RAM), or spin transfer torque (STT)-MRAM, spintronic magnetic junction memory-based devices, magnetic tunnel junction (MTJ)-based devices, DW (domain wall) and SOT (spin-orbit transfer)-based devices, thyristor-based memory devices, or combinations of any of the above devices, or other memories. The memory device may refer to the die itself and / or the packaged memory product. In some embodiments, 3D crosspoint memory (e.g., Intel 3D XPoint TM The memory may include a transistor-free stackable cross-point architecture in which memory cells are located at the intersection of word lines and bit lines and are individually addressable, and in which bit storage is based on changes in bulk resistance.

[0058] In some embodiments, the operator input device(s) 308 are configured to provide inputs indicative of one or more operating characteristics of the transmission 120, 230 and / or the vehicle 200 associated with the transmission 120, 230. In one example, the device(s) 308 may provide inputs generated by an operator of the vehicle 200 associated with the transmission 120, 230 (e.g., inputs for applying compensated clutch pressure to at least one torque-transmitting mechanism 142 under certain operating conditions). Of course, it should be understood that in other embodiments, the device(s) 308 may be embodied as or otherwise include any device or collection of devices capable of providing other suitable inputs indicative of one or more operating characteristics of the transmission 120, 230, one or more operating characteristics of the vehicle associated with the transmission 120, 230, and / or one or more characteristics associated with the operating environment of the vehicle 200 associated with the transmission 120, 230.

[0059] In some embodiments, the torque-transmitting mechanism(s) 142 include one or more sensors 316 and one or more control devices 318, each of which is communicatively coupled to the controller 302. The sensor(s) 316 may include or otherwise embody any electrical device or collection of electrical devices capable of providing input data indicative of one or more operating characteristics of the mechanism(s) 142, such as, for example, measuring clutch pressure delivered to the mechanism(s) 142 during a shift from one operating mode of the transmission 120, 230 to another. Additionally, in some embodiments, the sensor(s) 316 may include a proximity sensor, such as a capacitive proximity sensor, an inductive proximity sensor, or a Hall effect sensor. The control(s) 318 may include or otherwise embody any hydraulic or electromechanical device or collection of such devices capable of controlling the fluid pressure delivered to the mechanism(s) 142, such as one or more pressure control solenoids, a trim system, a trim valve, an on / off solenoid, a switching valve, a logic valve, or the like.

[0060] In some embodiments, the brake(s) 320 include one or more sensors 322 and one or more control devices 324, each of which is communicatively coupled to the controller 302. The sensor(s) 322 may include or otherwise embody any electrical device or collection of electrical devices capable of providing input data indicative of one or more operating characteristics of the brake(s) 320, such as, for example, measuring clutch pressure delivered to the brake(s) 320 during a shift from one operating mode of the transmission 120, 230 to another. Additionally, in some embodiments, the sensor(s) 322 may include a proximity sensor, such as a capacitive proximity sensor, an inductive proximity sensor, or a Hall effect sensor. The control(s) 324 may include or otherwise embody any hydraulic or electromechanical device or collection of such devices capable of controlling the fluid pressure delivered to the brake(s) 320, such as one or more pressure control solenoids, a trim system, a trim valve, an on / off solenoid, a switching valve, a logic valve, or the like.

[0061] Dashboard 326 of illustrative control system 300 includes a display 328 and a user interface 330. Display 328 is configured to output or display various indications, messages, and / or prompts to an operator, which may be generated by control system 300. User interface 330 is configured to provide various inputs to control system 300 based on various actions, which may include actions performed by an operator.

[0062] Reference Figure 4 In the illustrative embodiment, controller 302 establishes environment 400 during operation. Illustrative environment 400 includes an output speed processing module 402, an upcoming clutch pressure adjustment determination module 404, and a clutch pressure compensation module 406. Each module, logic, and other components of environment 400 may be embodied as hardware, firmware, software, or a combination thereof. Thus, in some embodiments, one or more modules of environment 400 may be embodied as a collection of circuits or electrical devices. In such embodiments, one or more of output speed processing module 402, upcoming clutch pressure adjustment determination module 404, and clutch pressure compensation module 406 may form part of processor(s) 304 and / or other components of controller 302. Furthermore, in some embodiments, one or more of the illustrative modules may collectively form part of another module, and / or one or more of the illustrative modules may be independent of one another. Furthermore, in some embodiments, one or more modules of environment 400 may be embodied as virtualized hardware components or emulation architectures that may be established and maintained by processor(s) 304 or other components of controller 302.

[0063] The output speed processing module 402 may be embodied as hardware, firmware, software, virtualized hardware, emulation architecture, and / or combinations thereof as described above, and is configured to monitor the speed of the output shaft 124 based on input provided by the sensor 150. Furthermore, in some embodiments, the output speed processing module 402 is configured to determine a difference between the monitored output speed and a reference output speed (such as, for example, a reference output speed stored in the memory 306). To this end, in an illustrative embodiment, the output speed processing module 402 may perform the following reference processing: Figure 7 Described method.

[0064] The upcoming clutch pressure adjustment determination module 404 may be embodied as hardware, firmware, software, virtualized hardware, simulation architecture, and / or combinations thereof as described above and is configured to determine an upcoming clutch (e.g., one of the torque-transmitting mechanisms 142) pressure adjustment based on the determined difference between the monitored output speed and the reference output speed. To this end, in the illustrative embodiment, the upcoming clutch pressure adjustment determination module 404 may execute the following reference to Figure 8 Described method.

[0065] The clutch pressure compensation module 406 may be embodied as hardware, firmware, software, virtualized hardware, simulation architecture, and / or combinations thereof as described above, and is configured to determine a compensated clutch pressure or pressure command to be applied to a clutch (e.g., one of the torque-transmitting mechanisms 142) based on the determined upcoming clutch pressure adjustment. To this end, in the illustrative embodiment, the clutch pressure compensation module 406 may execute the following with reference to Figure 9 Described method.

[0066] Reference Figure 5 , the model 500 illustrates various inputs provided to the controller 302 and features / functions performed by the controller 302 to suppress vibrations at the output shaft 124 of the transmission 120, 230 during use of the vehicle 200. In some embodiments, the controller 302 (e.g., the output speed processing module 402, the upcoming clutch pressure adjustment determination module 404, and / or the clutch pressure compensation module 406) can execute or implement the model 500 during use of the transmission 120, 230. Additionally, in some embodiments, the following references to the functions performed by the controller 302 are provided. Figure 6 The described method 600 is effective for executing or implementing the model 500 in use of the transmission 120 , 230 .

[0067] Model 500 illustratively includes a speed processing loop or portion 510 and a control loop or portion 520. In at least some embodiments, execution of speed processing loop 510 by controller 302 begins upon first or initial detection of a rotational target disposed proximate output shaft 124 (e.g., by output speed sensor 150). In one example, the rotational target may be any single tooth from a plurality of teeth formed on or proximate output shaft 124. In such embodiments, the first or initial detection of a tooth may prompt the initiation of (i) speed sampling in speed processing loop 510 and (ii) clutch pressure adjustment determination and control in control loop 520 in a synchronous or substantially synchronous manner. Thus, in at least some embodiments, the present disclosure contemplates synchronous or substantially synchronous execution of speed processing loop 510 and control loop 520 by controller 302, which may advantageously avoid time delays associated with periodic sampling in other configurations. Furthermore, in at least some embodiments, synchronous or substantially synchronous execution of the speed processing loop 510 and the control loop 520 by the controller 302 in response to initial detection of a rotating target can offset lag typically experienced during hydraulic actuation of the torque transmitting mechanism(s) 142 .

[0068] During execution of the illustrative speed processing loop 510, the controller 302 monitors the output speed of the transmission 120, 230 (i.e., based on the input signal provided by the output speed sensor 150) and compares the monitored output speed, or actual output speed, to a reference output speed, or desired output speed, which may be stored in the memory 306 of the controller 302. In the illustrative embodiment, output speed monitoring during execution of the speed processing loop 510 takes into account driveline disturbances (e.g., jerk) detectable at the output shaft 124. Based on the results of the comparison, the controller 302 determines a difference, or error, between the monitored output speed and the reference output speed.

[0069] During execution of the illustrative control loop 520, the controller 302 calculates an upcoming clutch pressure adjustment based on the difference between the monitored output speed and the reference output speed determined during execution of the speed processing loop 510. Furthermore, during execution of the illustrative control loop 520, the controller 302 determines a compensated clutch pressure to be applied to the torque-transmitting mechanism(s) 142 based on an upcoming base clutch pressure command (which may be stored in the memory 306 of the controller 302) and the calculated adjustment to dampen vibrations at the output shaft 124 during use of the transmission 120, 230.

[0070] Reference Figure 6 An illustrative method 600 for suppressing vibrations at the output shaft 124 of the transmission 120, 230 may include or be embodied as a set of instructions executable by the controller 302. The method 600 corresponds to or is otherwise related to the following in Figure 6 However, it should be understood that the method 600 can be performed in one or more sequences other than the illustrative sequence.

[0071] The illustrative method 600 begins at block 602. In block 602, the controller 302 monitors the true or actual speed of the output shaft 124 based on input provided by the output speed sensor 150. In some embodiments, in response to the above reference Figure 5 The monitoring step is performed by the controller 302 in block 602 during the initial detection of the rotating target discussed above. Additionally, in some embodiments, the monitoring step is performed by the controller 302 in block 602 during execution of the velocity processing loop 510 of the model 500. Additionally, in some embodiments, the monitoring step is performed by the controller 302 in block 602 at least in part according to the following reference. Figure 7 In the depicted method 700 , the monitoring step is performed by the output speed processing module 402 in block 602 . Regardless, the method 600 proceeds from block 602 to block 604 .

[0072] In block 604 of the illustrative method 600, the controller 302 determines a difference between the monitored actual speed of the output shaft 124 and a reference output speed. In some embodiments, the reference output speed is stored in the memory 306 of the controller 302. Furthermore, in some embodiments, the reference output speed is established based on the condition that the powertrain is subjected to negligible or minimal disturbances during a predetermined shift from one operating mode of the transmission 120, 230 to another operating mode. Furthermore, in some embodiments, the controller 302 determines the difference in the steps of block 604 during execution of the speed processing loop 510 of the model 500. Furthermore, in some embodiments, the reference output speed is stored in the memory 306 of the controller 302 based on the condition that the powertrain is subjected to negligible or minimal disturbances during a predetermined shift from one operating mode of the transmission 120, 230 to another operating mode. Figure 7 In the depicted method 700 , the difference is determined by the output speed processing module 402 during the step of block 604 . Regardless, the method 600 proceeds from block 604 to block 606 .

[0073] In block 606 of the illustrative method 600, the controller 302 determines an adjustment to the oncoming clutch pressure of the torque transmitting mechanism(s) 142 based on the difference determined in the step of block 604. In some embodiments, the controller 302 determines the adjustment in the step of block 606 during execution of the control loop 520 of the model 500. Additionally, in some embodiments, the adjustment is determined at least in part according to the following reference to Figure 8 In the depicted method 800, the adjustment is determined by the oncoming clutch pressure adjustment determination module 404 during the step of block 606. Regardless, the method 600 proceeds from block 606 to block 608.

[0074] In block 608 of the illustrative method 600, the controller 302 determines the compensated clutch pressure to be applied to the torque transmitting mechanism(s) 142 based on the adjustment determined in the step of block 606. In some embodiments, during execution of the control loop 520 of the model 500, the controller 302 determines the compensated clutch pressure in the step of block 608. Additionally, in some embodiments, at least in part according to the following reference to Figure 9 In the depicted method 900 , the compensated clutch pressure is determined by the clutch pressure compensation module 406 during the step of block 608 . Regardless, the method 600 proceeds from block 608 to block 610 .

[0075] In block 610 of the illustrative method 600, the controller 302 applies the compensated clutch pressure determined in block 608 to the torque-transmitting mechanism(s) 142 to dampen vibrations at the output shaft 124. The present invention contemplates applying the compensated clutch pressure by the controller 302 to the torque-transmitting mechanism(s) 142 in block 610 as an alternative to software implementation of a mechanical damper physically coupled to the output shaft 124. In some embodiments, the controller 302 applies the compensated clutch pressure in block 610 during execution of the control loop 520 of the model 500.

[0076] Reference Figure 7 An illustrative method 700 for monitoring the actual speed of the output shaft 124 and determining the difference between the monitored speed and a reference speed may include or be embodied as a set of instructions executable by the controller 302 (e.g., the output speed processing module 402). The method 700 corresponds to or is otherwise related to the following in Figure 7 However, it should be understood that the method 700 can be performed in one or more sequences other than the illustrative sequence.

[0077] The illustrative method 700 begins at block 702. In block 702, the controller 302 receives input from the output speed sensor 150 indicating an actual speed of the output shaft 124. From block 702, the method 700 proceeds to block 704.

[0078] In block 704 of the illustrative method 700, the controller 302 retrieves a reference output speed to compare with the speed input received in the steps of block 702. In some embodiments, to perform the steps of block 704, the controller 302 retrieves the reference output speed from one or more lookup tables stored in the memory 306. From block 704, the method 700 proceeds to block 706.

[0079] In block 706 of the illustrative method 700, the controller 302 compares the reference output speed retrieved in the step of block 704 to the speed input received in the step of block 702. From block 706, the method 700 proceeds to block 708.

[0080] In block 708 of the illustrative method 700 , the controller 302 determines a difference between the reference output speed and the received speed input based on the results of the comparison performed in the steps of block 706 .

[0081] Reference Figure 8An illustrative method 800 for determining an adjustment to an upcoming clutch pressure for one or more torque transmitting mechanisms 142 based on the difference determined in the steps of block 708 may include or be embodied as a set of instructions executable by the controller 302 (e.g., the upcoming clutch pressure adjustment determination module 404). The method 800 corresponds to or is otherwise related to the following description of the present invention. Figure 8 However, it should be understood that the method 800 can be performed in one or more sequences other than the illustrative sequence.

[0082] The illustrative method 800 begins at block 802. In block 802, the controller 302 calculates an adjustment to the oncoming clutch pressure of the torque-transmitting mechanism(s) 142 based on the difference determined in block 708 of the method 700. In some embodiments, the calculations performed in block 802 may be based on a lookup table or reference table stored in the memory 306 of the controller 302. From block 802, the method 800 proceeds to block 804.

[0083] In block 804 of the illustrative method 800 , the controller 302 converts the adjustment calculated in block 802 into a desired clutch pressure command. In some embodiments, the conversion performed in block 804 may be based on a lookup table or reference table stored in the memory 306 of the controller 302 .

[0084] Reference Figure 9 , an illustrative method 900 for determining a compensated clutch pressure to be applied to the torque transmitting mechanism(s) 142 may include or be embodied as a set of instructions executable by the controller 302 (e.g., the clutch pressure compensation module 406). The method 900 corresponds to or is otherwise related to the following in Figure 9 However, it should be understood that the method 900 can be performed in one or more sequences other than the illustrative sequence.

[0085] The illustrative method 900 begins at block 902. In block 902, the controller 302 receives or retrieves an upcoming base clutch pressure command for the torque-transmitting mechanism(s) 142, which may be established for a particular shift or transition from one operating mode of the transmission 120, 230 to another. In the illustrative embodiment, the upcoming base clutch pressure command does not take into account driveline disturbances (e.g., shudder) experienced during operation of the transmission 120, 230. In some embodiments, the upcoming base clutch pressure command may be based on a lookup table or reference table stored in the memory 306 of the controller 302. In any case, the method 900 proceeds from block 902 to block 904.

[0086] In block 904 of the illustrative method 900, the controller 302 receives or retrieves the desired clutch pressure command determined in the steps of block 804. In the illustrative embodiment, the desired clutch pressure command takes into account driveline disturbances (e.g., shudder) experienced during operation of the transmission 120, 230. From block 904, the method 900 proceeds to block 906.

[0087] In block 906 of the illustrative method 900, the controller 302 determines a compensated clutch pressure to be applied to the torque-transmitting mechanism(s) 142 based on the upcoming base clutch pressure command and the desired clutch pressure command. In some embodiments, in block 906, the controller 302 determines a compensated clutch pressure command representing the compensated clutch pressure. Furthermore, in some embodiments, based on the compensated clutch pressure command determined in block 906, the controller 302 applies the compensated clutch pressure to the torque-transmitting mechanism(s) 142 to account for powertrain disturbances (e.g., judder) experienced during operation of the transmission 120, 230.

[0088] Reference Figure 10A and Figure 10B In the illustrative embodiment, when the controller 302 does not perform any damping operation (e.g., according to the damping operation of the method 600), Figure 10A Output shaft vibrations characterized by judder are depicted in region 1010. Such vibrations may have frequencies in the range of 5-20 Hz, varying depending on the specific gear shift during which the judder occurs and the specific vehicle configuration. In contrast, where the controller 302 performs damping operations, output shaft vibrations and judder are not present in the vehicle. Figure 10B It will not appear in the illustrated area 1020.

[0089] While the invention has been illustrated and described in detail in the foregoing drawings and description, it is to be considered illustrative and not restrictive, and it is to be understood that only illustrative embodiments of the invention have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims

1. A vehicle comprising: chassis; a plurality of wheels coupled to the chassis; as well as The power system installed on the chassis includes a transmission. The input shaft receives torque from the drive unit, Output shaft that transmits torque to the load, at least one torque transmitting mechanism coupled between the input shaft and the output shaft, and a control system comprising an output speed sensor providing an input signal representative of a rotational speed of the output shaft and a controller communicatively coupled to the output speed sensor, in: The controller includes a processor and a memory having instructions stored therein, and The instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft based on the input signal, determine a difference between the monitored rotational speed of the output shaft and a reference rotational speed, determine an adjustment amount for an upcoming clutch pressure to be applied to the at least one torque transmitting mechanism based on the difference, determine a compensated clutch pressure to be applied to the at least one torque transmitting mechanism based on the adjustment amount, and apply the compensated clutch pressure to the at least one torque transmitting mechanism to suppress vibration at the output shaft during vehicle use. 2 . The vehicle of claim 1 , wherein the vehicle has no mechanical shock absorber coupled to the output shaft.

3. The vehicle of claim 2 , wherein the instructions are executable by the processor to cause the processor to apply the compensated clutch pressure to the at least one torque-transmitting mechanism to suppress vibrations at the output shaft during a transition from one operating mode of the transmission to another operating mode of the transmission.

4. The vehicle of claim 1 , wherein to determine the difference between the monitored rotational speed of the output shaft and the reference rotational speed, the instructions are executable by the processor to cause the processor to receive the input signal from the output speed sensor, retrieve the reference rotational speed of the output shaft, compare the input signal with the reference rotational speed, and determine the difference based on a result of the comparison.

5. The vehicle of claim 4 , wherein to determine the adjustment to the oncoming clutch pressure, the instructions are executable by the processor to cause the processor to calculate the adjustment based on the difference between the monitored speed of the output shaft and the reference speed, and to convert the calculated adjustment into a desired clutch pressure command.

6. The vehicle of claim 5 , wherein to determine the compensated clutch pressure, the instructions are executable by the processor to cause the processor to receive an upcoming base clutch pressure command, receive a desired clutch pressure command, and determine the compensated clutch pressure based on the upcoming base clutch pressure command and the desired clutch pressure command.

7. The vehicle of claim 1 , wherein to monitor the rotational speed of the output shaft, the instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft in response to an initial detection by the output speed sensor of a rotating target disposed proximate the output shaft. 8 . The vehicle according to claim 7 , wherein the rotation target is any one of a plurality of teeth formed on the output shaft.

9. The vehicle of claim 7, wherein initial detection of the rotating target by the output speed sensor offsets hysteresis in hydraulic actuation of the at least one torque transmitting mechanism.

10. A transmission comprising: The input shaft receives torque from the drive unit, Output shaft that transmits torque to the load, at least one torque transmitting mechanism coupled between the input shaft and the output shaft, and a control system comprising an output speed sensor providing an input signal representative of a rotational speed of the output shaft and a controller communicatively coupled to the output speed sensor, in: The controller includes a processor and a memory having instructions stored therein, and The instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft based on the input signal, determine a difference between the monitored rotational speed of the output shaft and a reference rotational speed, and determine an adjustment to an upcoming clutch pressure to be applied to the at least one torque-transmitting mechanism based on the difference, and The transmission has no mechanical damper coupled to the output shaft.

11. The transmission of claim 10 , wherein to determine the adjustment to the upcoming clutch pressure, the instructions are executable by the processor to cause the processor to calculate the adjustment based on the difference between the monitored speed of the output shaft and the reference speed, and to convert the calculated adjustment into a desired clutch pressure command.

12. The transmission of claim 10 , wherein to determine the difference between the monitored speed of the output shaft and the reference speed, the instructions are executable by the processor to cause the processor to receive the input signal from the output speed sensor, retrieve the reference speed of the output shaft, compare the input signal with the reference speed, and determine the difference based on a result of the comparison.

13. The transmission of claim 10, wherein to monitor the rotational speed of the output shaft, the instructions are executable by the processor to cause the processor to monitor the rotational speed of the output shaft in response to an initial detection by the output speed sensor of any one of a plurality of teeth disposed proximate to the output shaft. 14 . The transmission of claim 13 , wherein initial detection of any one of the plurality of teeth by the output speed sensor offsets a hysteresis in hydraulic actuation of the at least one torque transmitting mechanism. 15 . The transmission of claim 10 , wherein the instructions are executable by the processor to cause the processor to determine a compensated clutch pressure to be applied to the at least one torque transmitting mechanism based on the adjustment amount.

16. The transmission of claim 15, wherein the instructions are executable by the processor to cause the processor to apply the compensated clutch pressure to the at least one torque transmitting mechanism to dampen vibrations at the output shaft in use of the transmission.

17. A method of suppressing vibrations at an output shaft of a transmission, the method comprising: monitoring, by a controller, a rotational speed of the output shaft based on an input signal provided by an output speed sensor; determining, by the controller, a difference between the monitored rotational speed of the output shaft and a reference rotational speed; determining, by the controller, an adjustment to an oncoming clutch pressure to be applied to at least one torque-transmitting mechanism of the transmission based on the difference; determining, by the controller, a compensated clutch pressure to be applied to the at least one torque transmitting mechanism based on the adjustment amount; as well as The compensated clutch pressure is applied by the controller to the at least one torque transmitting mechanism to dampen vibrations at the output shaft during use of the transmission. 18 . The method of claim 17 , wherein applying the compensated clutch pressure to the at least one torque transmitting mechanism comprises damping vibrations at the output shaft without using a mechanical damper coupled to the output shaft.

19. The method of claim 17, wherein monitoring the rotational speed of the output shaft comprises monitoring the rotational speed of the output shaft in response to initial detection by the output speed sensor of any one of a plurality of teeth disposed proximate the output shaft.

20. The method of claim 19, wherein initial detection of any one of the plurality of teeth by the output speed sensor offsets hysteresis in hydraulic actuation of the at least one torque transmitting mechanism.

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