SYSTEMS AND METHODS FOR SPEED CONTROL OF WHEELS OF A VEHICLE
20220314816 · 2022-10-06
Inventors
- Kang Wang (Palos Verdes Estates, CA, US)
- Boru Wang (Torrance, CA, US)
- Chia-Chou Yeh (Torrance, CA, US)
- Brian Harries (Redondo Beach, CA, US)
Cpc classification
B60W2050/0008
PERFORMING OPERATIONS; TRANSPORTING
B60W2050/0012
PERFORMING OPERATIONS; TRANSPORTING
B60L15/025
PERFORMING OPERATIONS; TRANSPORTING
B60L3/08
PERFORMING OPERATIONS; TRANSPORTING
B60L2220/46
PERFORMING OPERATIONS; TRANSPORTING
B60W2552/15
PERFORMING OPERATIONS; TRANSPORTING
B60W30/182
PERFORMING OPERATIONS; TRANSPORTING
B60W30/18172
PERFORMING OPERATIONS; TRANSPORTING
B60L2240/42
PERFORMING OPERATIONS; TRANSPORTING
B60W30/045
PERFORMING OPERATIONS; TRANSPORTING
B60L15/20
PERFORMING OPERATIONS; TRANSPORTING
B60L2260/28
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60L15/20
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Systems and methods are provided herein for controlling the speed on each wheel of a vehicle, possibly operating a vehicle in a speed control mode. In response to receiving input to engage speed control mode and receiving an accelerator pedal input, the system determines a target wheel speed based on the accelerator pedal input, monitors wheel speed of each of a plurality of wheels and determines, for each monitored wheel, a difference based on the monitored wheel speed and the target wheel speed. A torque is provided to each of the plurality of wheels based on the respective difference to achieve the target wheel speed.
Claims
1. A method for speed control of wheels of a vehicle, the method comprising: determining a target wheel speed for each of a plurality of wheels of the vehicle based on an accelerator pedal input; monitoring wheel speed of each of the plurality of wheels of the vehicle; determining, for each of the plurality of wheels, a difference based on the monitored wheel speed and the target wheel speed; and adjusting a torque to each of the plurality of wheels based on the respective difference to achieve the target wheel speed, wherein each of the plurality of wheels is connected to a respective motor configured to provide the respective torque.
2. The method of claim 1, wherein one or more of the target wheel speeds cause the vehicle to make a zero radius turn.
3. The method of claim 1, wherein each respective motor comprises an electric motor and wherein the monitoring wheel speed of each of a plurality of wheels of the vehicle, comprises: monitoring signals from sensors coupled to motor shafts of the electric motors, wherein each sensor indicates an amount of rotation of a respective motor shaft; and calculating each wheel speed based on a respective signal of the monitored signals.
4. The method of claim 1, wherein each of the motors comprises an independent electric motor with a motor shaft, and wherein each of the motor shafts comprises a sensor, the method further comprising: determining one or more signals from each of the sensors, wherein the wheel speed for each of the plurality of wheels is monitored based at least on the one or more signals.
5. The method of claim 1, wherein the difference for one or more wheels of the plurality of wheels based on the monitored wheel speed and the target wheel speed indicates the wheel speed exceeds the target wheel speed, and wherein adjusting the torque to the one or more wheels of the plurality of wheels in an opposite direction as the one or more wheels of the plurality of wheels is spinning to reduce the wheel speed.
6. The method of claim 1, wherein the providing the torque to each of the plurality of wheels is performed in a reaction speed of less than 100 microseconds.
7. The method of claim 1, further comprising: detecting one or more declining surfaces associated with the plurality of wheels; and determining a maximum wheel speed less than 30 MPH based on the one or more declining surfaces.
8. The method of claim 1, wherein the adjusting the torque to each of the plurality of wheels to achieve the target wheel speed comprises: providing an open-loop forward torque to wheels on a first side of the vehicle; and providing an open-loop backward torque to wheels on a second side of the vehicle, wherein the first side is one of a left side and a right side of the vehicle, wherein the second side is one of the left side and the right side of the vehicle, and wherein the second side is opposite to the first side.
9. The method of claim 1, further comprising engaging in a vehicle yaw mode; while operating in the vehicle yaw mode: providing an open-loop torque to the plurality of wheels of the vehicle; identifying a slippage for one or more wheels of the plurality of wheels of the vehicle; and in response to the identifying slippage for one or more wheels of the plurality, providing a closed-loop torque to the one or more wheels of the plurality of wheels of the vehicle identified as slipping.
10. The method of claim 1, the method further comprising: engaging a speed control mode; determining a gap between one or more wheels of the plurality of wheels and one or more ground surfaces; automatically engaging in speed control mode in response to determining the gap.
11. The method of claim 1, wherein the plurality of wheels comprises four wheels and wherein the vehicle comprises four electric motors, each of the four electric motors configured to provide the torque to a respective one of the four wheels.
12. A system for speed control of wheels of a vehicle, the system comprising: input circuitry configured to receive an accelerator pedal input control circuitry configured to: determine a target wheel speed based for each of a plurality of wheels of the vehicle on the accelerator pedal input; monitor wheel speed of each of the plurality of wheels of the vehicle; determine, for each of the plurality of wheels, a difference based on the monitored wheel speed and the target wheel speed; and adjust a torque to each of the plurality of wheels based on the respective difference to achieve the target wheel speed, wherein each of the plurality of wheels is connected to a respective motor configured to provide the respective torque.
13. The system of claim 12, wherein one or more of the target wheel speeds cause the vehicle to make a zero radius turn.
14. The system of claim 12, wherein each respective motor comprises an electric motor and wherein the control circuitry is configured to monitor wheel speed of each of the plurality of wheels of the vehicle by: monitoring signals from sensors coupled to motor shafts of the electric motors, wherein each sensor indicates an amount of rotation of a respective motor shaft, and calculating each wheel speed based on a respective signal of the monitored signals.
15. The system of claim 12, wherein each of the motors comprises an independent electric motor with a motor shaft, and wherein each of the motor shafts comprises a sensor, the method further comprising: determining one or more signals from each of the sensors, wherein the wheel speed for each of the plurality of wheels is monitored based at least on the one or more signals.
16. The system of claim 12, wherein the difference for one or more wheels of the plurality of wheels based on the monitored wheel speed and the target wheel speed indicates the wheel speed exceeds the target wheel speed, and wherein adjusting the torque to the one or more wheels of the plurality of wheels in an opposite direction as the one or more wheels of the plurality of wheels is spinning to reduce the wheel speed.
17. The system of claim 12, wherein the control circuitry is configured to provide the torque to each of the plurality of wheels is performed in a reaction speed of less than 100 microseconds.
18. The system of claim 12, wherein the control circuitry is further configured to: detect one or more declining surfaces associated with the plurality of wheels, and determine a maximum wheel speed less than 30 MPH based on the one or more declining surfaces.
19. The system of claim 12, wherein the control circuitry is configured to adjust the torque to each of the plurality of wheels to achieve the target wheel speed by: provide an open-loop forward torque to wheels on a first side of the vehicle; and provide an open-loop backward torque to wheels on a second side of the vehicle, and wherein the first side is one of a left side and a right side of the vehicle, wherein the second side is one of the left side and the right side of the vehicle, and wherein the second side is opposite to the first side.
20. A vehicle comprising: a plurality of electric motors, each comprising a motor shaft coupled to a respective one of a plurality of wheels of the vehicle; an accelerator pedal configured to provide an accelerator pedal input; power electronics configured to output power to each of the plurality of electric motors to generate a respective torque to a respective wheel; a plurality of sensors, each configured to output a signal indicating a wheel speed of a corresponding wheel of the vehicle; input circuitry configured to receive the accelerator pedal input and the signals of the plurality of sensors; control circuitry configured to: determine a target wheel speed for each of a plurality of wheels of the vehicle based on the accelerator pedal input; monitor, using the signals of the plurality of sensors, wheel speed of each of the plurality of wheels; determine, for each of the plurality of wheels, a difference based on the monitored wheel speed and the target wheel speed; and adjust the torque to be generated to each of the plurality of wheels based on the respective difference to achieve the target wheel speed.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present disclosure, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the concepts disclosed herein and should not be considered limiting of the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of illustration, these drawings are not necessarily made to scale.
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
DETAILED DESCRIPTION
[0031] The present disclosure is directed to operating a vehicle in a speed control mode. In speed control mode, the vehicle's wheels are operated at a target wheel speed for better control of the vehicle on uneven and different friction surfaces when using two or more motors. In some embodiments, the vehicle includes a normal turning mode where the vehicle is steered by changing the angle of the front wheels relative to a vertical axis (e.g., each relative to a respective vertical 170 of
[0032] In some embodiments, the present disclosure employs, in reference to
[0033] In some embodiments, in reference to
[0034] As referred to herein, the term “speed control mode” refers to any kind of mode, a mode triggered/entered automatically without user input, or technique for operating a vehicle such that torque provided to each of the wheels achieves a target wheel speed as determined from an accelerator pedal input. In some embodiments, the target wheel speed may be proportional to the accelerator pedal input. For example, the accelerator pedal input of 50% percent corresponds to a target wheel speed of 15 mph when a maximum wheel speed is 30 mph. In some embodiments, the maximum wheel speed in the speed control mode may be adjusted. Based on the accelerator pedal being pressed 50% percent, each wheel receives torque to achieve the 15-mph target wheel speed. For example, a wheel that is on a slippery ground (e.g., wet surface, icy surface) may reach 15 mph with very little torque applied. On the other hand, a wheel that is on higher friction ground (e.g., gravel surface, pavement) may require higher torque to achieve 15 mph. In another embodiment, the target wheel speed may be based on different user inputs. For example, the user may input the target wheel speed with a button, a turn lever, a paddle shifter or via voice command using voice control or any other method or a combination thereof.
[0035] As referred to herein, the term “vehicle yaw mode” refers to any kind of mode, a mode triggered automatically without user input, or technique for operating a vehicle such that outer and inner wheels of the vehicle are provided with torques in opposite directions. The term “outer” refers to the wheels on the side of the vehicle that are provided with forward torque and the term “inner” refers to the wheels on the side of the vehicle on which the wheels are provided with backward torque. Accordingly, which wheels of the vehicle are considered the outer and inner wheels will depend on the direction of yaw. In some embodiments, the vehicle yaw mode includes independent torque control of each wheel which is correlated to a wheel speed at each wheel. For example, the outer wheels of the vehicle are operated with forward torques and the inner wheels of the vehicle are operated with backward torque. In some embodiments, as a vehicle moves between surfaces that change in friction, the processing circuitry 722 adjusts the torque to each wheel based on the monitored wheel speed and the target wheel speed. In some embodiments, the vehicle yaw mode includes independently controlling each wheel to induce a yawing of the vehicle. For example, the outer front wheel of the vehicle is operated with a first forward torque, the outer rear wheel is operated with a second forward torque, the inner front wheel of the vehicle is operated with a first backward torque and the inner rear wheel is operated with a second backward torque. In some embodiments, the inner wheel is referred to as the first side, and the outer wheel is referred to as the second side.
[0036]
[0037] In some embodiments, vehicle 100 may include a front left wheel 102, front right wheel 104, rear left wheel 106, and rear right wheel 108. In some embodiments, vehicle 100 may include a motor 112. Motor 112 may be connected to front left wheel 102 (e.g., via a belt, chains, gears, or any other connection device). Vehicle 100 may also include motors 114, 116, 118, which are similarly connected to wheels 104, 106, 108, respectively. In some embodiments, motors 112, 114, 116, and 118 may be configured to provide forward torque or backward torque to their respective wheels 102, 104, 106, and 108. In some embodiments, vehicle 100 may include an accelerator pedal 113 configured to provide an accelerator pedal input to a vehicle dynamic controller 111 configured to convert the accelerator pedal input to a target wheel speed. In some embodiments, vehicle 100 may include a resolver 142 attached at motor 112 and configured to monitor and send a signal from the resolver 142 to the vehicle dynamic controller 111. Further, the vehicle dynamic controller 111 communicates with each resolver 142, 144, 146, 148 coupled at each motor (112, 114, 116, 118) via the respective communications lines (132, 134, 136, 138).
[0038] In some embodiments, motors 112, 114, 116, and 118 may be any kind of motors capable of generating power (e.g., gas motors, gas-electric hybrids motors, electric motors, battery-powered electric motors, hydrogen fuel cell motors). In some embodiments, motors 112, 114, 116, and 118 may be battery-powered electric motors configured for vehicle drive, propulsion, by utilizing a plurality of battery cells packaged together to create one or more battery modules or assemblies to store energy and release the energy upon request. In some embodiments, motors 112, 114, 116, and 118 may be devices connected to a primary single motor (not shown) and configured to independently transfer power from a single motor to wheels 102, 104, 106, and 108, respectively. For example, motors 112, 114, 116, and 118 may independently transfer power to wheels 102, 104, 106, and 108, respectively, such that wheels 104 and 108 spin in one direction (e.g., forward direction) and wheels 102 and 106 spin in an opposite direction (e.g., backward direction), thereby enabling vehicle 100 to establish a zero-degree turning radius (i.e., vehicle yawing via vehicle yaw mode). In some embodiments, a vehicle yaw mode includes independently controlling each wheel to induce a yawing of the vehicle. For example, in a vehicle yaw mode, motors 112 and 116 may be configured to provide forward torque to their wheels 102 and 106, respectively and motors 114 and 118 may be configured to provide backward torque to their wheels 104 and 108. In some embodiments, wheels 104 and 108 may spin with a 500 rpm in a one direction/clockwise (e.g., forward direction) and wheels 102 and 106 spin in the opposite direction/counterclockwise direction (e.g., backward direction), thereby enabling vehicle 100 to perform a smooth turn.
[0039] In some embodiments, vehicle 100 may include processing circuitry 722. In some embodiments, the processing circuitry may include an on-board vehicle computer that is capable of controlling multiple features or capabilities of the vehicles. In some embodiments, processing circuitry may be communicatively connected with user inputs (e.g., graphical user interface) of the vehicle 100, sensors of the vehicle, and transitory or non-transitory memory (e.g., memory that stores instructions for operating the vehicle).
[0040] In some embodiments, vehicle 100 may include a plurality of sensors. For example, some of the plurality of sensors may include sensors for determining the speed of vehicle 100, the degree to which the front wheels 102, 104 of vehicle 100 are turned, vehicle rotation sensor to determine the rotation of the vehicle in a vehicle yaw mode, wheel rotation sensors (e.g., resolvers 142, 144, 146, 148) to determine the wheel speed of each of the wheels 102, 104, 106, and 108 of vehicle 100, and accelerometer sensor.
[0041] In some embodiments, the processing circuitry of vehicle 100 may be capable of directly controlling features of vehicle 100 with or without user input. In one example, processing circuitry may be able to actuate motor 112 to provide a specified amount of backward or forward torque to front left wheel 102 to achieve a target wheel speed. Similarly, processing circuitry may be able to actuate any of motors 114, 116, 118 to provide a specified amount of backward or forward torque to wheels 104, 106, 108, respectively, to achieve a target wheel speed.
[0042] In some embodiments, front left wheel 102 and front right wheel 104 may be connected via a drive shaft (not shown). As shown in
[0043] In some embodiments, when making a left yaw, vehicle 100 may provide backward torques (T.sub.R1 and T.sub.R2), based on the friction on the ground to achieve the target wheel speed, to the left wheels (e.g., front left wheel 102 and rear left wheel 106). In some embodiments, the vehicle may provide forward torques (T.sub.F1 and T.sub.F2) based on the friction on the ground to achieve the target wheel speed (e.g., target wheel speed is proportional to the accelerator pedal input) to the right wheels (e.g., front right wheel 104 and rear right wheel 108). For example, the vehicle 100 may provide forward torque T.sub.F1 to the front right wheel 104 and may further provide forward torque T.sub.F2 to the rear right wheel 108. In some embodiments, the vehicle 100 may provide backward torques (T.sub.R1 and T.sub.R2) based on the friction on the ground to achieve the target wheel speed (i.e., target wheel speed is proportional to the accelerator pedal input) to the left wheels (e.g., front left wheel 102 and rear left wheel 106). For example, vehicle 100 may provide backward torque T.sub.R1 to the front left wheel 102 and may further provide backward torque T.sub.R2 to the rear left wheel 106. Each of the forward torques T.sub.F1 and T.sub.F2, backward torques T.sub.R1 and T.sub.R2 are independent torques and are a function of the respective wheel speed. For example, a front right wheel 104 is on high friction ground 122 (e.g., pavement, gravel) and, as a result, requires higher torque T.sub.F1 than torque T.sub.F2 for the rear right wheel 108, which is on low friction ground 126 (e.g., icy road, sand, wet road).
[0044] In some embodiments, on a relatively consistent ground surface, the torque applied to each wheel 102, 104, 106, and 108 to achieve the target wheel speed should be substantially similar, approximately the same, substantially the same, among other possibilities contemplated herein. In another embodiment, on a relatively consistent ground surface, vehicle 100 may consider the payload in vehicle 100 to provide the torque to the wheels 102, 104, 106, and 108. For example, if vehicle 100 is carrying heavy material in the rear of vehicle 100, the torque applied to each wheel 102, 104, 106, and 108 to achieve the target wheel speed will vary based on the payload. In some embodiments, sensors 712-721 on the vehicle 100 suspension may transmit a signal to the vehicle dynamic control regarding the weight at each wheel. Based on the weight at each wheel 102, 104, 106, and 108, the processing circuitry 722 may adjust the torque to each wheel 102, 104, 106, and 108 to achieve the target wheel speed. Specifically, the torque to the rear wheels 106 and 108 may be higher to overcome the extra payload.
[0045] In some embodiments, the speed control mode can be used in any vehicle 100 capable of distributing torque, which can include braking, and monitoring wheel speed of each wheel 102, 104, 106, and 108. For example, the vehicle 100 may provide for independent distribution of torque to the right wheels 104 and 108 and the left wheels 102 and 106. According to another example, vehicle 100 may provide for the independent distribution of torque and braking to the left wheels 102 and 106 and the right wheels 104 and 108. According to another example, vehicle 100 may provide for the independent distribution of torque and braking to the left front wheel 102, the rear left wheel 106, the front right wheel 104 and the rear right wheel 108. The foregoing enables a driver to have accurate control of the center of rotation (e.g., zero-radius turn) while also performing the rotation smoothly.
[0046] The foregoing
[0047] In some embodiments, a method for controlling a vehicle 100 may include determining a target wheel speed for each of one or more wheels of the vehicle 100. In some embodiments, vehicle 100 has two wheels or three wheels or four wheels. Based on the number of wheels a vehicle 100 has, the method determines a wheel speed target for each wheel based on an accelerator pedal input. For example, the processing circuitry 722 detects an actual wheel speed for each of the one or more wheels 102, 104, 106, 108 which are controlled by one or more independent motors 112, 114, 116, 118 respectively. In some embodiments, the processing circuitry may determine one or more target torques for each of the one or more wheels based at least on the actual wheel speed and the target wheel speed for each of the wheel. For such an example, each of the target wheel speeds is configured with a target torque. The target torques may be adjusted by one or more independent motors 112, 114, 116, 118 to achieve one or more target torques.
[0048]
[0049] In some embodiments, the processing circuitry 722 may further monitor an incline of the vehicle based on a tilt sensor. For example, the vehicle may be in an incline position, a banked position, or a combination thereof. In some embodiments, the inclined position includes front wheels of the vehicle being in a higher position than rear wheels or the rear wheels of the vehicle being in the higher position than the front wheels. For example, the vehicle being on a hill with a front of the vehicle being higher than a rear of the vehicle. Alternatively, the vehicle may be on the incline, with the rear of the vehicle being higher than the front of the vehicle. In some embodiments, the banked position includes outer wheels (e.g., first side) of the vehicle being in the higher position than the inner wheels (e.g., second side) or the inner wheels (e.g., second side) of the vehicle being in the higher position than the outer wheel (e.g., first side). For example, the vehicle being on a hill sideways, with an inner side of the vehicle being higher than the outer side of the vehicle. Alternatively, with an outer side of the vehicle being higher that the inner side of the vehicle. In some embodiments, the processing circuitry may compare the incline of the vehicle against a vehicle incline threshold (e.g., 10% incline grade, 8% incline grade, etc.). The processing circuitry, in response to determining that the vehicle incline is below the vehicle incline threshold, may initiate a vehicle yaw mode or a speed control mode.
[0050] In some embodiments, vehicle 200 may include front left wheel 208, front right wheel (not shown), rear left wheel 206 and rear right wheel (not shown). In some embodiments, the vehicle may be on an uneven surface 203. In some embodiments, the vehicle may be on an uneven surface 203 with different friction surfaces (202 and 204) on the ground. In some embodiments, the different friction surfaces may include a lower friction surface 202 and a higher friction surface 204. In some embodiments, based on the different friction surfaces (202 and 204) and the uneven surface 203 the vehicle is positioned on, the vehicle may provide individual torque to each of the wheels (206 and 208) as well as rear right wheel (not shown) and front right wheel (not shown) for the wheels to achieve the target wheel speed. For example, as the vehicle is positioned on uneven surface 203 (e.g., incline), the torque 212 applied to each of the front left wheel 208 and front right wheel (not shown) is lower to account for the incline than the torque 210 applied to the rear left wheel 206 and rear right wheel (not shown). Specifically, as the vehicle's front is raised because of the uneven surface 203 (e.g., incline), the vehicle's weight is redistributed over the wheels 206 and 208, with more weight placed on the rear left wheel 206 and rear right wheel (not shown) because of the incline. In some embodiments, as a result of the uneven surface 203 (e.g., incline), the torque applied to each of the rear wheel 206 and rear right wheel (not shown) is greater than the torque applied to the front wheels 208 and front right wheel (not shown). For illustrative purposes, the size of the arrow 210 and 212 is indicative of the amount of torque applied (i.e., a larger arrow indicates higher torque, and a smaller arrow indicates a lower torque).
[0051]
[0052] In some embodiments, vehicle 300 may include front left wheel 308, front right wheel (not shown), rear left wheel 306 and rear right wheel (not shown). In some embodiments, the vehicle 300 is on an even surface 303 (e.g., flat or approximately flat, substantially flat) with different friction surfaces on the ground. In some embodiments, the different friction surfaces include a lower friction surface 302 and a higher friction surface 304. In some embodiments, based on the different friction surfaces 302 and 304 on the ground, the vehicle 300 may provide torques 310 and 312 to each of the wheels, front left wheel 308, front right wheel (not shown), rear left wheel 306 and rear right wheel (not shown), for the wheels to achieve the target wheel speed. In some embodiments, vehicle 300 may provide independent torque to each wheel 306 and 308 on vehicle 300. For example, as vehicle 300 is positioned on even surface 303 with different surface frictions 302 and 304, the torques 310 and 312 applied to each of the front left wheel 308, front right wheel (not shown), rear left wheel 306 and rear right wheel (not shown), is proportional to the friction surface. Specifically, as friction under each wheel 306, 308 increases (e.g., the wheel moves from wet pavement to dry pavement), the amount of torque required for wheels 306, 308 to maintain the target wheel speed may increase. Similarly, as friction under each wheel 306, 308 decreases (e.g., the wheel moves from wet pavement to ice), the amount of torque required for wheels 306, 308 to maintain the target wheel speed may decrease. In some embodiments, when the wheel speed for wheel 308 is higher than the target wheel speed, vehicle 300 may apply a brake to wheel 308 or provide torque in the opposite direction or may reduce power to wheel 308, among other possibilities contemplated herein. Similarly, when the wheel speed for wheel 306 is higher than the target wheel speed, vehicle 300 may apply a brake to wheel 306 or provide torque in the opposite direction or may reduce power to the wheel, among other possibilities contemplated herein. In some embodiments, as a result of the different friction surfaces 302 and 304, the torque applied to the rear left wheel 306 may be less than the torque applied to the front left wheel 308. For illustrative purposes, the size of the arrow 310 and 312 is indicative of the amount of torque applied (i.e., a larger arrow 312 indicates higher torque, and a smaller arrow 310 indicates a lower torque).
[0053]
[0054]
[0055] Process 500 begins at 502, where the processing circuitry may receive input to engage speed control mode. For example, the processing circuitry may engage the speed control mode after the user issues a command requesting such mode (e.g., by pressing an appropriate button, a paddle shifter, via an input on a graphical user interface, or any other input). Yet, referring back to
[0056] In some embodiments, the processing circuitry may determine a gap between one or more wheels of the plurality of wheels and one or more ground surfaces (e.g., based on a pressure sensor or a calculated surface friction). For example, as vehicle 100 is traversing an uneven surface 203, the front left wheel 208 (
[0057] Process 500 continues at 504, where the processing circuitry 722 may proceed depending on the outcome of step 502. For example, if the number of engagement criteria is satisfied, the processing circuitry may proceed to step 504. At 504, the processing circuitry may receive an accelerator pedal input from accelerator pedal 113. For example, the user may have pressed the accelerator pedal input 50%. The user may press the accelerator pedal input from a range of “0” zero (i.e., no accelerator pedal input) to 100% (i.e., pedal to the floor board). In some embodiments, the accelerator pedal input may be preprogramed and automatically provided a preset pedal input to the each of the motors.
[0058] In some embodiments, step 504 starts ramping up torque in an open-loop mode (i.e., without adjusting the torque based on monitoring any sensor data). For example, in the open-loop mode, the torque applied to each wheel ramps up regardless of the accelerator pedal input. Referring back to
[0059] In some embodiments, the processing circuitry 722 may provide the open loop torque to each of the plurality of wheels to achieve the wheel slippage. For example, providing an open-loop forward torque to wheels 102 and 106 on a first side 150 of the vehicle 100 by providing an open-loop backward torque to wheels 104 and 108 on a second side 160 of the vehicle 100. Upon a wheel slipping, the processing circuitry may engage a closed-loop mode, where the processing circuitry monitors the wheel speed. The torque is increased or decreased until the monitored wheel speed corresponds to the target wheel speed. In some embodiments, step 504 starts ramping up torque in a closed-loop mode where the amount of torque provided to the wheels is based on the amount the accelerator pedal is pressed. For example, in the closed-loop mode, the torque applied to each wheel is based on sensors monitoring vehicle outputs, e.g., wheel speed, regardless of the accelerator pedal input. For example, consider one or more motors 112, 114, 116, and 118 configured to provide and/or generate torque to one or more of the wheels 102, 104, 106, and 108, respectively based on the monitored wheel speed at each wheel. In this example, motors 114 and 118 may generate closed-loop forward torque to wheels 104 and 108, respectively. Further, motors 112 and 116 may generate closed-loop backward torque to wheels 102 and 106, respectively. For example, the amount of torque may be proportional to the amount the accelerator pedal is pressed or may be determined using a lookup table. In another example, the amount of torque may be based on a difference between the monitored wheel speed and the target wheel speed.
[0060] Process 500 continues at 506, where the processing circuitry may proceed depending on the outcome of step 504. For example, if the accelerator pedal input is received, the processing circuitry may proceed to step 506. At 506, the processing circuitry may determine a target wheel speed based on the accelerator pedal input. For example, in response to receiving an accelerator pedal input, the processing circuitry determines a target wheel speed based on how far the user pressed the accelerator pedal. In one embodiment, the target wheel speed is proportional to how far the user has pressed the accelerator pedal. For example, an accelerator pedal input of 25% is proportional to 25% of the maximum target speed. The range that the wheel may spin can be adjusted. In some embodiments, the range is set for a speed of 0-30 mph with the maximum target speed of 30 mph. In this example, an accelerator pedal input of 25% is proportional to 7.5 mph. In another example, an accelerator pedal input of 50% is proportional to 15 mph. In another embodiment, the target wheel speed is a user issued command requesting such target wheel speed (e.g., by pressing an appropriate button, a paddle shifter, via an input on a graphical user interface, or any other input). In an aspect of this embodiment, the target wheel speed may be adjusted with the appropriate button, a paddle shifter, or via an input on a graphical user interface. In this configuration, the amount the user has pressed the accelerator pedal does not correlate to the wheel speed.
[0061] At 508, the processing circuitry may monitor the wheel speed of each of a plurality of wheels of the vehicle. In some embodiments, the wheel speed is determined by one or more vehicle sensors (e.g., resolvers) configured to measure the rotation of the vehicle motors (e.g., at the motor shaft). The vehicle's sensors monitor the sensor signal of the motors to determine the wheel speed for each wheel and transmit this information to control circuitry. In another embodiment, the wheel speed is determined by one or more vehicle sensors configured to measure actual wheel speed (e.g., a sensor coupled to the axle). In some embodiments, the control circuitry may be communicatively connected to one or more sensors that provide data indicative of the wheel speed for each wheel of the vehicle. For example, sensors 712 of
[0062] In some embodiments, process 500 continues at 510, where the processing circuitry 722 may determine, for each wheel, a difference based on the monitored wheel speed and the target wheel speed. In some embodiments, the processing circuitry may determine that monitored wheel speed is less than the target wheel speed, monitored wheel speed is approximately equal to the target wheel speed, or monitored wheel speed is greater than the target wheel speed. In some embodiments, process 500 continues at 512, where processing circuitry performs a decision tree. Specifically, based on monitored wheel speed (M) and target wheel speed (T), processing circuitry determines whether differences exists and provides torque to each wheel based on the respective differences.
[0063] In some embodiments, if the differences are zero (“0”) (i.e., M=T) or if the differences are within a small number (e.g., ±1 mph), the process 500 continues at 516, by maintaining the torque applied to each wheel and going back to step 504, to receive the current accelerator pedal input from the user. For example, the accelerator pedal input may vary over time as the operator of the vehicle adjusts the pedal position.
[0064] In some embodiments, if the monitored wheel speed (M) is less than the target wheel speed (T) for a wheel at 512 (i.e., M<T), the process 500 continues at 514, to provide increased torque to the wheel based on the difference to achieve the target wheel speed. In some embodiments, the processing circuitry 722 may actuate any one of motors 112, 114, 116, and 118 to provide increased torque to corresponding wheel 102, 104, 106, or 108.
[0065] In some embodiments, if the monitored wheel speed (M) is greater than the target wheel speed (T) for a wheel at 512 (i.e., M>T), the process 500 continues at 518 to provide reduced or opposite torque to the wheel based on the difference to achieve the target wheel speed. In some embodiments, the processing circuitry 722 may actuate any one of motors 112, 114, 116, and 118 to provide reduced or opposite (i.e., opposite of the direction of the monitored wheel speed) torque to any one of wheels 102, 104, 106, and 108. In some embodiments, the processing circuitry applies mechanical braking to provide opposite torque to a wheel exceeding (e.g., greatly exceeding) the target wheel speed.
[0066] In some embodiments, the torque applied to each of the plurality of wheels based on the respective difference (irrespective of the difference being greater than or less than the target wheel speed), to achieve the target wheel speed, may be performed by a proportional-integral-derivative controller (PID controller). In some embodiments, the processing circuitry implements the PID controller and may continuously calculate a respective difference between the monitored wheel speed (M) and the target wheel speed (T) and apply torque based on proportional, integral, and derivative terms (denoted P, I, and D, respectively). For example, if only a small difference between the monitored wheel speed and target wheel speed is observed, change in the torque applied is proportionally small.
[0067] In some embodiments, the torque applied to each of the plurality of wheels based on the respective difference may be based on a threshold. In some embodiments, the processing circuitry 722 may determine a difference between the monitored wheel speed (M) and the target wheel speed (T) of greater than a first threshold (e.g., ±5 mph of target wheel speed), and in response, may provide a first torque (e.g., 50% torque) to each wheel with the difference to achieve the target speed. In some embodiments, the processing circuitry may determine a difference of greater than a second threshold (e.g., ±10 mph of target wheel speed). In response, the processing circuitry may provide a second torque (e.g., maximum torque) to each wheel with the difference to achieve the target speed.
[0068] It will be understood that process 500 is merely illustrative and various modifications can be made within the scope of the disclosure. For example, in some embodiments, steps 506, 508, and 510 can be omitted and step 512 can be performed in response to the accelerator pedal being pressed.
[0069]
TABLE-US-00001 TABLE 1 Accelerator Target Wheel pedal input (%) Speed (mph) 0% 0 5% 1.5 10% 3 15% 4.5 20% 6 25% 7.5 30% 9 35% 10.5 40% 12 45% 13.5 50% 15 55% 16.5 60% 18 65% 19.5 70% 21 75% 22.5 80% 24 85% 25.5 90% 27 95% 28.5 100% 30
[0070]
[0071] Processing circuitry 722 may include hardware, software, or both, implemented on one or more modules configured to provide control of front wheels 726 and 728 and rear wheels 730 and 732 of a vehicle. In some embodiments, processor 708 includes one or more microprocessors, microcontrollers, digital signal processors, programmable logic devices, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or any suitable combination thereof. In some embodiments, processor 708 is distributed across more than one processor or processing units. In some embodiments, processing circuitry 722 executes instructions stored in memory for managing a quad motor vehicle 100, or a triple motor vehicle (not shown) or a dual motor vehicle (not shown). In some embodiments, memory 710 is an electronic storage device that is part of processing circuitry 722. For example, memory 710 may be configured to store electronic data, computer instructions, applications, firmware, or any other suitable information. In some embodiments, memory 710 includes random-access memory, read-only memory, hard drives, optical drives, solid-state devices, or any other suitable memory storage devices, or any combination thereof. For example, memory may be used to launch a start-up routine. The communication interface 707 may include electrical terminals, level shifters, a communications module, connectors, cables, antennas, any other suitable components for transmitting and receiving information, or any combination thereof. For example, the communications interface 707 may include an Ethernet interface, a Wi-Fi interface, an optical interface, a sensor interface (e.g., for interacting with one or more sensors 712-721), any other suitable wired or wireless interface, or any combination thereof. To illustrate, the communication interface 707 may include a sensor interface having a power supply, analog-to-digital converter, digital-to-analog converter, signal processing equipment, signal conditioning equipment, connectors, electrical terminals, any other suitable components for managing signals to and from a sensor, or any combination thereof. To illustrate further, a sensor interface may be configured to communicate with the resolvers 712 (e.g., a rotary encoder coupled to the motor shaft or gear shaft), vehicle yaw sensor 714, orientation sensor 716, speed sensor 718, accelerometer sensor 720 (e.g., a vibration sensor), steering wheel angle sensor 721, any other suitable sensor or any combination thereof. In some embodiments, communications interface 707 is configured to transmit a control signal indicative of a motor command to each wheel 102, 104, 106, 108 of vehicle 100. In some embodiments, communication interface 707 is incorporated into processing circuitry 722, motor/brake controller 724, or both.
[0072] In some embodiments, the system may include resolvers 712, vehicle yaw sensor 714, orientation sensor 716, speed sensor 718, accelerometer sensor 720 and steering wheel angle sensor 721. In some embodiments, the control circuitry may be communicatively connected to resolvers 712 (e.g., a sensor) which may be coupled to a motor shaft of the motor (e.g., motor 112, 114, 116, 118 from
[0073] Illustrative system 700 of
[0074] It is contemplated that the steps or descriptions of each of
[0075] It will be apparent to those of ordinary skill in the art that methods involved in the present disclosure may be embodied in a computer program product that includes a computer-usable and/or readable medium. For example, such a computer-usable medium may consist of a read-only memory device, such as a CD-ROM disk or conventional ROM device, or a random access memory, such as a hard drive device or a computer diskette, having a computer-readable program code stored thereon. It should also be understood that methods, techniques, and processes involved in the present disclosure may be executed using processing circuitry. The processing circuitry, for instance, may be a general-purpose processor, a customized integrated circuit (e.g., an ASIC), or a field-programmable gate array (FPGA) within any vehicle 100.
[0076] The foregoing is merely illustrative of the principles of this disclosure and various modifications may be made by those skilled in the art without departing from the scope of this disclosure. The above-described embodiments are presented for purposes of illustration and not of limitation. The present disclosure also can take many forms other than those explicitly described herein. Accordingly, it is emphasized that this disclosure is not limited to the explicitly disclosed methods, systems, and apparatuses, but is intended to include variations to and modifications thereof, which are within the spirit of the following claims.