Vehicle yaw and energy efficiency control apparatus to dynamically assign torque among independently powered drive wheels

Abstract

A circuit budgets torque among independent field-oriented motor control circuits. A desired vehicle yaw turning moment is received from an operator control input. The circuit determines a positive or negative torque target for each electrically powered drive wheel and transmits it to an adaptive field-oriented motor control circuit which provides voltage magnitude and voltage frequency to a poly-phase synchronous alternating current electric motor. When wheel loading, limited traction, or stability prevents any motor from attaining the torque target, that data is returned to the budgeting circuit and torque budget is adjusted for all adaptive field-oriented motor control circuits. Varying numbers of powered wheels are assigned torque depending on vehicle dynamics. Performance of the vehicle can be adapted to driver capabilities. A vehicle may serve as a driving simulator for diverse vehicles.

Claims

1. A method for operation of a torque budgeting and torque assignment apparatus for electric propulsion control comprising executable instructions stored in a non-transitory medium, the method comprising: receiving from a user control interface a desired vehicle yaw; receiving from a wheel sensor a measured wheel rotation rate; receiving from road surface sensor actual vehicle direction and speed; receiving from a road surface sensor, road condition; receiving from a motor controller, attainable torque; on a condition that attainable torque is less than assigned torque for a first wheel, reassigning a torque budget among the non-first wheels; determining as a steering response, positive delta torque to be assigned to all wheels on the outside of a turn and negative delta torque to be assigned to all wheels on the inside of a turn according to a selection of stored parameterized profiles of vehicle characteristics and driver skill level which control a torque budgeting circuit for desired vehicle yaw turning moment; determining positive or negative delta torque for each powered drive wheel when measured vehicle yaw does not equal desired vehicle yaw; and, transmitting, to at least one electric motor controller via a network, at least one of a target torque, and a target magnitude and associated target angular measure; wherein the target magnitude is one of an amplitude for an electrical current and an amplitude for a voltage, and, the target angular measure is one of a frequency and a phase angle.

2. The method of claim 1, further comprising: on the condition of aggressive cornering, applying yaw controlled power to budget torque among at least four wheels; on the condition of inclement weather, applying yaw controlled power to budget torque among at least for wheels; on the condition of poor road conditions, applying yaw controlled power to budget torque among at least four wheels; on the condition of speed above a threshold and when not turning, distributing power to wheels associated with only one axle; on the condition of speed above the threshold, and when not turning, distributing power to wheels associated with only one axle; on the condition of speed below a threshold, distributing power to one or more wheels associated with only one axle and if turning, to only one wheel of the only one axle; on the condition of speed below a slow threshold and a wheel angle greater than a turning threshold which defines an arc, assigning torque to a single wheel which is a larger radius from a center of the arc; and transmitting, to at least one electric motor controller via network, at least one of a target torque, and a target magnitude and associated target angular measure; wherein the target magnitude is one of an amplitude for an electrical current and an amplitude for a voltage, and, the target angular measure is one of a frequency and a phase angle.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

(2) FIG. 1 is a block diagram of a system;

(3) FIG. 2 is a flowchart of processes in a method of operation of the components of apparatuses of the system; and

(4) FIG. 3 is a block diagram of components of an apparatus.

DETAILED DISCLOSURE OF EMBODIMENTS OF THE INVENTION

(5) In these embodiments, computing devices once embedded in this real-time closed loop control system, lose their generic capability for executing instructions other than continuously responding to physical measurements of indicia by setting electrical magnitudes and frequencies.

(6) A system is disclosed which includes a torque budgeting apparatus, at least four motor controllers each coupled to a powered wheel, sensors, an operator control unit, and a network coupling all the above components.

(7) An apparatus is disclosed which has interfaces to receive measurements and indicia of operator desired control values, circuits to assign torque to at least one of the electric propulsion motor controllers, circuits to receive attainable torque from the motor controllers, and a torque budget transformation circuit. In an embodiment, a driver/vehicle personalization profile store is coupled to the torque budget transformation circuit.

(8) One aspect of the invention is a method operable by a processor performing steps encoded as instructions on a non-transitory media, to control distribution of electric energy to at least one traction drive coupled to a wheel comprising: sensing the steering direction and speed of the vehicle; on the condition of speed below a threshold, distributing power to one or more wheels associated with only one axle and if turning to only one wheel of the only one axle; on the condition of speed above a threshold and when not turning, distributing power to wheels associated with only one axle; on the condition of aggressive cornering applying yaw controlled power to budget torque among at least four wheels; on the condition of inclement weather applying yaw controlled power to budget torque among at least four wheels; and on the condition of poor road conditions applying yaw controlled power to budget torque among at least four wheels.

(9) The network communicates inputs such as measured yaw, vertical loading of each wheel, measured torque, wheel orientation, wheel speed, and tire slip. In an embodiment, the network distributes these inputs to each other wheel and to the yaw control apparatus.

(10) The network communicates a desired torque value or a delta torque value for each traction drive and returns a confirmation or error message from each motor control circuit. Each traction drive may calculate parameters for its own motor configuration.

(11) Drive parameters include a current, voltage, frequency, or phase for each wheel calculated by the yaw control apparatus. The drive parameters may be transmitted to each wheel if the wheel's control circuit does not calculate from the desired torque.

(12) A digital yaw control apparatus is communicatively coupled to a user interface and to a network. The network connects at least one control drive for each wheeled electric motor and provides a digital torque packet to said control drive. The control drive provides current or voltage to the wheeled motor. The control drive modulates the amplitude of the current or voltage. The control drive modulates the frequency or phase of the current or voltage. The wheeled electric motor has a torque sensor and transmits the resulting torque back to the digital yaw control apparatus. An authentication circuit ensures that the correct wheeled motor receives the digital torque packet and that the packet was transmitted by the correct control drive.

(13) In one embodiment for two wheel control, the invention controls torque at a left and at a right rear wheels or at a left and a right front wheel, which eliminates the needs for at least one mechanical differential gear or any electronically controlled differential. As a function of the steering angle, steering speed, throttle pedal position, yaw velocity and vehicle speed, the apparatus applying negative torque to the left or right wheel, as required.

(14) In one embodiment, this means that when entering a corner at high speed, moderate negative torque values are transmitted to the inside rear wheel. Simultaneously positive drive torque values transmitted to the outside rear wheel supports the steering motion of the car.

(15) One aspect of the invention is a system including a processor coupled to non-transitory computer readable media and communicatively coupled to an operator interface and communicatively coupled to one or more electrical powered propulsion apparatuses.

(16) The system determines a difference between desired vehicle yaw and measured vehicle yaw to determine a value for delta torque for each propulsion apparatus.

(17) The system determines a value for positive or negative desired torque for each of the one or more electrically powered propulsion apparatuses and transmits the desired target torque to each of the one or more electrically powered propulsion apparatuses.

(18) In embodiments, the system transmits a value as a digital value; or in another embodiment as an amplitude; or in another embodiment as a phase angle or as a frequency. In embodiments the system determines and transmits the value as a complex number. In an embodiment, the system further has at least one yaw sensor. In an embodiment, the system further has at least one pitch sensor. In an embodiment, the system further has at least one roll sensor. In an embodiment, the system further has at least one acceleration sensor.

(19) In one embodiment of the invention, an electrically powered propulsion apparatus has one or more wheels, one electric motor per wheel, a motor controller per wheel, and at least one sensor. The electrically powered propulsion apparatus further includes a surface sensor to report a vector of actual travel direction and speed. In an embodiment the system also has an edge of pavement sensor.

(20) An apparatus receives measurements from a wheel speed sensor, wheel orientation, and operator control inputs on desired yaw turning moment, and desired vehicle acceleration. The apparatus determines torque assignment to each electrically powered drive wheel. A circuit determines when one or more wheels is in a spin or skid condition. A circuit determines when the vehicle is in a steady state or cruise condition. A circuit determines when the vehicle is in a slow speed turning condition. A circuit determines when the vehicle is in an aggressive cornering condition. A circuit determines how many and which wheels should be assigned a torque budget.

(21) In some implementations, the method could utilize a highly customized digital or analog processor coupled to motor controllers to supply poly-phase electrical current or voltage.

(22) In one embodiment, a processor performing steps encoded as instructions on a non-transitory media, to control distribution of electric energy to at least one traction drive coupled to a wheel would cause sensing the steering direction and speed of the vehicle; on the condition of speed below a threshold, distributing power to one or more wheels associated with only one axle and if turning to only one wheel of the only one axle; on the condition of speed above a threshold and when not turning, distributing power to wheels associated with only one axle; on the condition of aggressive cornering applying yaw controlled power to budget torque among at least four wheels; on the condition of inclement weather applying yaw controlled power to budget torque among at least four wheels; and on the condition of poor road conditions applying yaw controlled power to budget torque among at least four wheels.

(23) In an embodiment, the apparatus further performs receiving, via a network communication interface, the following inputs measured yaw, vertical loading of each wheel, measured torque, wheel orientation, wheel speed, and tire slip.

(24) In an embodiment, the apparatus further performs transmitting, via a network communication interface, measured yaw, vertical loading of each wheel, measured torque, wheel orientation, wheel speed, and tire slip to each other wheel.

(25) In an embodiment, the apparatus further performs transmitting, via a network communication interface, a desired torque value or a delta torque value for each traction drive; and receiving a confirmation or error message from each motor control circuit.

(26) In an embodiment, the apparatus further performs receiving and distributing a yaw prediction for future delta torques from a user interface such as a gps or map or heads-up display or goggles.

(27) In an embodiment, the system has a filter for noise and high frequency clutter, one of a digital signal processor, a hardware discrete cosine transform (DCT), and a software algorithm.

(28) Another aspect of the invention is a system for electric propulsion vehicle control, which has a wheel rotation sensor; a vehicle direction and speed sensor; a road surface sensor; at least four poly-phase electric motor controllers, each poly-phase electric motor controller coupled to a poly-phase electric propulsion motor; an operator control interface which measures and transmits desired vehicle acceleration and desired vehicle yaw; a torque budgeting apparatus; and a network communicatively coupling the above components.

(29) Another aspect of the invention is a torque budgeting apparatus to control independently powered electric drive wheels which includes: a torque budget transformation circuit; an interface to a network to transmit and receive desired and attainable torque assignments; a circuit to receive measured desired vehicle acceleration and desired vehicle yaw; a circuit to receive measured wheel rotation and orientation; and a circuit to receive measured vehicle yaw and measured surface speed.

(30) In an embodiment, the apparatus also has a circuit to measure wheel spin/skid relative to a surface.

(31) In an embodiment, the apparatus also has a circuit to receive from each motor controller an attainable torque.

(32) In an embodiment, the apparatus also has a circuit to compare vehicle speed with thresholds.

(33) In an embodiment, the apparatus also has a circuit to compare wheel angle with a threshold.

(34) In an embodiment, the apparatus also has a circuit to compare desired and measured vehicle yaw with a threshold.

(35) In an embodiment, the apparatus also has a non-transitory selectable driver/vehicle personalization store.

(36) In an embodiment, the apparatus also has a circuit to measure wind, humidity, temperature, and proximity to another vehicle.

(37) In an embodiment, the apparatus also has a circuit to measure stability, road surface, lateral acceleration, wheel loading, pitch, and roll.

(38) In an embodiment, the torque budget transformation circuit determines a spin/skid condition by comparison of wheel speed with surface speed whereupon torque assignment is caused to be reduced or reassigned until all wheels regain traction or wheel speed is within a few percent (e.g. single digit) of surface speed.

(39) In an embodiment, the torque budget transformation circuit determines a condition when attainable torque at a wheel is substantially below assigned torque, causing a torque budget to be reassigned among electrically powered drive wheels.

(40) In an embodiment, the torque budget transformation circuit reads a selected driver/vehicle personalization profile store to alter acceleration/deceleration and steering response to operator controls whereby a driver's ability can be met or trained for a different vehicle dynamic.

(41) In an embodiment, the torque budget transformation circuit determines a condition when operator desired yaw is greater than measured vehicle yaw, causing delta negative torque increment to be assigned to an inside rear wheel and delta positive torque increment to be assigned to an outside rear wheel.

(42) In an embodiment, the torque budget transformation circuit determines a condition when operator desired yaw is greater than a yaw threshold and when vehicle speed is greater than a fast threshold, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn.

(43) In an embodiment, the torque budget transformation circuit determines a condition of inclement weather, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn.

(44) In an embodiment, the torque budget transformation circuit determines a condition of poor road conditions, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn.

(45) In an embodiment, the torque budget transformation circuit on a condition when wheel angle is below a turning threshold and vehicle speed is substantially constant, assigns torque only to one pair of wheels on the same axle.

(46) In an embodiment, the torque budget transformation circuit on a condition of vehicle speed below a slow threshold and a wheel angle greater than a turning threshold which defines an arc, assigns torque solely to a single wheel which is a larger radius from a center of the arc.

(47) Another aspect of the invention is a method for operation of a torque budgeting and torque assignment apparatus for electric propulsion control comprising executable instructions stored in a non-transitory medium, the method comprising: receiving from a user control interface a desired vehicle acceleration and a desired yaw; receiving from a wheel sensor a measured wheel rotation rate; receiving from road surface sensor actual vehicle direction and speed; receiving from a road surface sensor, road condition; receiving from a motor controller, attainable torque; on a condition that attainable torque is less than assigned torque for a first wheel, reassigning a torque budget among the non-first wheels; determining acceleration/deceleration and steering response according to a selection of stored driver/vehicle personalization profiles; determining positive or negative delta torque for each powered drive wheel when measured vehicle yaw does not equal desired vehicle yaw; on the condition of aggressive cornering applying yaw controlled power to budget torque among at least four wheels; on the condition of inclement weather applying yaw controlled power to budget torque among at least four wheels; on the condition of poor road conditions applying yaw controlled power to budget torque among at least four wheels; on the condition of speed above a threshold and when not turning, distributing power to wheels associated with only one axle; on the condition of speed below a threshold, distributing power to one or more wheels associated with only one axle and if turning to only one wheel of the only one axle; on the condition of sped below a slow threshold and a wheel angle greater than a turning threshold which defines an arc, assigning torque to a single wheel which is a larger radius from a center of the arc; transmitting, to at least one electric motor controller via a network, at least one of a target torque, and a target magnitude and associated target angular measure; wherein the target magnitude is one of an amplitude for an electrical current and an amplitude for a voltage, and, the target angular measure is one of a frequency and a phase angle.

(48) It can be appreciated that the circuits may be implemented by processors using real time customized software closely coupled to physical measurements and resulting torque assignments in Newton meters transmitted to each motor controller. The physical manifestation of the invention is electric current magnitude or voltage magnitude and a poly-phase frequency or phase angle provided to a motor. Because of the dynamic nature of controlling a vehicle, the transformation method cannot be performed mentally or using manual computations.

(49) Referring now to the figures, FIG. 1 is a system diagram that illustrates one embodiment of an electric propulsion vehicle control 100 that includes: an operator control interface 110, a plurality of sensors 120 to measure physical parameters, a torque budgeting apparatus 300, poly-phase motor controllers 410-440, poly-phase electric propulsion motors, 510-540, all communicatively coupled by a network 600.

(50) FIG. 2 is a method 200 for operation of a torque budgeting and torque assignment apparatus for electric propulsion control comprising the following processes: 210 receiving from a user control interface a desired vehicle acceleration and a desired yaw; 220 receiving measurements from sensors such as, from a wheel sensor a measured wheel rotation rate, from road surface sensor actual vehicle direction and speed; from a road surface sensor, road condition; 230 receiving from a motor controller, attainable torque, and on a condition that attainable torque is less than assigned torque for a first wheel, reassigning a torque budget among the non-first wheels; 240 determining acceleration/deceleration and steering response according to a selection of stored driver/vehicle personalization profiles; 250 determining positive or negative delta torque for each powered drive wheel when measured vehicle yaw does not equal desired vehicle yaw; 260 on the condition of aggressive cornering applying yaw controlled power to budget torque among at least four wheels, or on the condition of inclement weather applying yaw controlled power to budget torque among at least four wheels, or on the condition of poor road conditions applying yaw controlled power to budget torque among at least four wheels; 270 on the condition of speed above a threshold and when not turning, distributing power to wheels associated with only one axle or on the condition of speed below a threshold, distributing power to one or more wheels associated with only one axle and if turning to only one wheel of the only one axle; 280 on the condition of sped below a slow threshold and a wheel angle greater than a turning threshold which defines an arc, assigning torque to a single wheel which is a larger radius from a center of the arc; and, transmitting 290, to at least one electric motor controller via a network, at least one of a target torque, and a target magnitude and associated target angular measure; wherein the target magnitude is one of an amplitude for an electrical current and an amplitude for a voltage, and, the target angular measure is one of a frequency and a phase angle.

(51) Referring now to FIG. 3, a torque budgeting apparatus to control independently powered electric drive wheels includes: a network interface 310, having a receiver 311 coupled to sensors and to an operator control interface and a transmitter 319 to provide torque commands to motor control circuits; a yaw control circuit 320; an energy conservation and efficiency optimization circuit 330; a spin/skid/slide traction recovery circuit 340; a route/road condition/weather anticipation circuit 350; and a driver/vehicle simulation circuit 360, coupled to a driver/vehicle personalization profile store 369.

(52) The network interface 310 transmits and receives desired and attainable torque assignments, receives measured desired vehicle acceleration and desired vehicle yaw, receives measured wheel rotation and orientation, and measured vehicle yaw and measure surface speed.

(53) The yaw control circuit 320 compares desired and measured vehicle yaw with a threshold, determines a condition when operator desired yaw is greater than a yaw threshold and when vehicle speed is greater than a fast threshold, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn; determines a condition of inclement weather, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn.

(54) The energy conservation efficiency optimization circuit 330 on a condition when wheel angle is below a turning threshold and vehicle speed is substantially constant, assigns torque only one pair of wheels on the same axle, on a condition of vehicle speed below a slow threshold and a wheel angle greater than a turning threshold which defines an arc, assigns torque solely to a single wheel which is a larger radius from a center of the arc.

(55) The spin/skid/slide traction recovery circuit 340 determines a spin/skid condition by comparison of wheel speed with surface speed whereupon torque assignment is caused to be reduced or reassigned until all wheels regain traction or wheel speed is within a few percent of surface speed, determines a condition of poor road conditions, causing negative torque to be assigned to all wheels on the inside of a turn and positive torque to be assigned to all wheels on the outside of a turn.

(56) The route/road condition/weather anticipation circuit 350 measures wind, humidity, temperature, and proximity to another vehicle, when attainable torque at a wheel is substantially below assigned torque, causing a torque budget to be reassigned among electrically powered drive wheels.

(57) The driver/vehicle simulation circuit 360 reads a selected driver/vehicle personalization profile store to alter acceleration/deceleration and steering response to operator controls whereby a driver's ability can be met or trained for a different vehicle dynamic.

(58) It is understood that circuits described above can be implemented as digital logic gates in a mask programmed standard cell or gate array. The circuits may equally be embodied in a programmable logic device depending on fuses or electrically erasable flash memory or firmware. The circuits may equally be embodied in Field Programmable Gate Arrays configured by non-transitory storage such as flash or read only memories (ROM). The circuits above may equally be embodied as processors adapted by instructions in non-transitory storage to perform the specific logic functions.

CONCLUSION

(59) The subject matter is easily distinguished as a real time control system with feedback from measurements of a vehicle's dynamic response to voltage or current magnitudes and frequency or phase commands individually assigned to each motor controller. Although processors are utilized to perform calculations continuously as the operator steers, accelerates, and decelerates, the invention is comparable to mechanical differentials which are patentable subject matter.

(60) The claimed subject matter is easily distinguished from conventional torque vectoring apparatus by receiving feedback from each adaptive field-oriented motor control what is attainable torque and amending the torque budget to each wheel. In a conventional system a central engine throttle and one or more hydraulic brake pistons is engaged to modify vehicle yaw torque. Electrically controlled wheels offer more dynamic positive and negative torque with far fewer mechanical linkages. Sensors locally attached to each wheel can provide slip and skid information directly to an adaptive field-oriented control (AF-OC) circuit. Each AF-OC circuit determines what its attainable torque can be for current conditions and transmits it to a torque budgeting circuit. The torque budgeting circuit can readjust its target torque commands in consideration of attainable torque for each wheel, user operations (steering), and lateral acceleration and stability data.

(61) The techniques described herein can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The techniques can be implemented as an embedded microcontroller, i.e., firmware tangibly embodied in a non-transitory medium, e.g., in a machine-readable storage device, for execution by, or to control the operation of circuit apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and connected by a wireless network.

(62) Method steps of the techniques described herein can be performed by one or more programmable processors executing a computer program to perform functions of the invention by operating on input data and generating output. Method steps can also be performed by, and apparatus of the invention can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Modules can refer to portions of the computer program and/or the processor/special circuitry that implements that functionality.

(63) Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices. The processor and the memory can be supplemented by, or incorporated in special purpose logic circuitry.

(64) A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, other network topologies may be used. Accordingly, other embodiments are within the scope of the following claims.