# US 10,308,137 B2 · Vehicle dynamics control in electric drive vehicles

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- Number: US 10,308,137 B2
- Document ID: US10308137B2
- Status: Granted
- Kind: B2
- Application number: 15/698,964
- Filed: 2017-09-08
- Published: 2018-01-25
- Granted: 2019-06-04
- Earliest claimed: 2010-03-29
- Assignees: Wrightspeed, Inc.
- Applicants: Wrightspeed, Inc.
- Inventors: Ian Wright; Ryan Cash
- Web page: https://patentgrep.com/patent/US10308137B2

## CPC

- B60L 15/20: for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
- B60L 3/102: {of individual wheels}
- B60L 15/2054: {by controlling transmissions or clutches}
- B60L 15/32: Control or regulation of multiple-unit electrically-propelled vehicles
- B60W 10/08: including control of electric propulsion units, e.g. motors or generators
- B60W 30/18172: {Preventing, or responsive to skidding of wheels}
- B60K 7/0007: {the motor being electric}
- B60L 15/2036: {Electric differentials, e.g. for supporting steering vehicles}
- B60L 2220/44: Wheel Hub motors, i.e. integrated in the wheel hub
- B60L 2220/46: Wheel motors, i.e. motor connected to only one wheel
- B60L 2240/461: Speed
- B60L 2240/465: Slip
- B60W 50/087: {where the control system corrects or modifies a request from the driver}
- B60W 2520/26: Wheel slip
- B60W 2720/26: Wheel slip
- Y02T 10/64: Electric machine technologies in electromobility
- Y02T 10/72: Electric energy management in electromobility
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Embodiments of the invention are directed toward a geared traction drive system configured to drive a wheel of a vehicle, comprising: a driveshaft for transmitting power to the wheel; an electric drive motor for driving the driveshaft, the electric drive motor configured to receive signals from a vehicle dynamic control system to command a required speed; a gear reduction component for reducing the speed of the motor by a predetermined factor to a lower speed suitable for driving the wheel; and a drive electronics component that works with the electric drive motor to drive the wheel to the speed commanded by the vehicle dynamic control system.

## Claims

### Claim 1

A vehicle dynamics control system, comprising:
a first velocity vector sensor;
a second velocity vector sensor;
one or more driver controls, selected from the group consisting of a steering angle sensor, a brake sensor, and an accelerator position sensor;
a first drive electronics module;
a first wheel;
a first motor, electrically coupled to the first drive electronics module and mechanically coupled to the first wheel;
a second drive electronics module;
a second wheel;
a second motor, electrically coupled to the second electronics module and mechanically coupled to the second wheel; and
a control processor, communicatively coupled to the first velocity vector sensor, the second velocity vector sensor, the one or more driver controls, the first drive electronics module, and the second drive electronics module and configured to
calculate a first wheel speed and a second wheel speed based on input from the first velocity vector sensor, the second velocity vector sensor, and the one or more driver controls such that each of the first wheel speed and the second wheel speed is less or equal to a speed corresponding an optimal slip rate and
to transmit the first wheel speed to the first drive electronics module and the second wheel speed to the second drive electronics module.

### Claim 2 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the first velocity vector sensor is positioned at a center of a first axle, and wherein the second velocity vector sensor is positioned at a center of a second axle, positioned at a different end of a vehicle than the first axle.

### Claim 3 (depends on 2)

The vehicle dynamics control system of claim 2, wherein the first velocity vector sensor is configured to measure and transmit to the control processor a speed and a direction of the center of the first axle, and wherein the second velocity vector sensor is configured to measure and transmit to the control processor a speed and a direction of the center of the second axle.

### Claim 4 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the first drive electronics module is configured to transmit a rotation speed of the first wheel to the control processor, and wherein the second drive electronics module is configured to transmit a rotation speed of the second wheel to the control processor.

### Claim 5 (depends on 4)

The vehicle dynamics control system of claim 4, wherein the control processor is configured to calculate one or more of an effective tire circumference of the first wheel, an effective tire circumference of the second wheel, a tire pressure of the first wheel, a tire pressure of the second wheel, a tire slip rate of the first wheel, a tire slip rate of the second wheel, a tire slip angle of the first wheel, and a tire slip angle of the second wheel.

### Claim 6 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the control processor is configured to calculate one or more of a yaw rate of a vehicle, a mass of the vehicle, and a cornering stiffness of the vehicle.

### Claim 7 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the optimal slip rate is selected from the group consisting of a preset optimal slip rate, an adjustable optimal slip rate, and an adaptive optimal slip rate.

### Claim 8 (depends on 7)

The vehicle dynamics control system of claim 7, wherein the optimal slip rate is the adaptive optimal slip rate, selected based on measuring acceleration values at multiple slip rates and identifying a slip rate with a highest one of the acceleration values.

### Claim 9 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the vehicle dynamics control system is operable for a direct control of vehicle's acceleration.

### Claim 10 (depends on 1)

The vehicle dynamics control system of claim 1, further comprising wherein the brake sensor is a brake pressure sensor.

### Claim 11 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the control processor is configured to determine a first regenerative braking level and transmit the first regenerative braking level to the first drive electronics module, and wherein the control processor is configured to determine a second regenerative braking level and transmit the second regenerative braking level to the second drive electronics module.

### Claim 12 (depends on 11)

The vehicle dynamics control system of claim 11, wherein the first regenerative braking level and the second regenerative braking level are determined, by the control processor, based on input from the brake sensor, the first velocity vector sensor, and the second velocity vector sensor.

### Claim 13 (depends on 11)

The vehicle dynamics control system of claim 11, wherein the first regenerative braking level and the second regenerative braking level are selected to be less or equal to a level corresponding an optimal slip rate.

### Claim 14 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the control processor is configured to yaw control of a vehicle based on the steering angle sensor, the first velocity vector sensor, and the second velocity vector sensor and repeatedly recalculating the first wheel speed and the second wheel speed.

### Claim 15 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the control processor is configured to calculate the first wheel speed and the second wheel speed such that an instant traction condition of each of the first wheel and the second wheel stays within a corresponding traction circle.

### Claim 16 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the first wheel is a front wheel, wherein the second wheel is a rear wheel, and wherein the control processor is configured to calculate the first wheel speed and the second wheel speed such that understeer conditions are created at traction limits of the first wheel and the second wheel.

### Claim 17 (depends on 1)

The vehicle dynamics control system of claim 1, further comprising a user interface, communicative coupled to the control processor and configured to display one or more of a traction margin, a traction circle, and a calculated friction coefficient.

### Claim 18 (depends on 1)

The vehicle dynamics control system of claim 1, wherein the first motor is mechanically coupled only to the first wheel, and wherein the second motor is mechanically coupled only to the second wheel.

### Claim 19 (depends on 1)

The vehicle dynamics control system of claim 1, further comprising:
a third drive electronics module;
a third wheel;
a third motor, electrically coupled to the third drive electronics module and mechanically coupled to the third wheel;
a fourth drive electronics module;
a fourth wheel; and
a fourth motor, electrically coupled to the second electronics module and mechanically coupled to the fourth wheel,
wherein the control processor is communicatively coupled to the third drive electronics module and the fourth drive electronics module and configured to
calculate a third wheel speed and a fourth wheel speed based on input from the first velocity vector sensor, the second velocity vector sensor, and the one or more driver controls such that each of the third wheel speed and the fourth wheel speed is less or equal to the speed corresponding the optimal slip rate and
to transmit the third wheel speed to the third drive electronics module and the fourth wheel speed to the fourth drive electronics module.

### Claim 20 (depends on 19)

The vehicle dynamics control system of claim 19, wherein the first wheel speed, the second wheel speed, the third wheel speed, and fourth wheel speed calculated by the control processor are different.