Vehicle rider detection using strain gauges

• US 9,908,580 B2
• Filed: 06/02/2017
• Issued: 03/06/2018
• Est. Priority Date: 06/02/2016
• Status: Active Grant

• Current Assignee: Future Motion, Inc.
• Original Assignee: Future Motion, Inc.
• Inventors: Doerksen, Kyle Jonathan, Wood, Daniel
• Primary Examiner(s): VANAMAN, FRANK BENNETT
• Application Number:
  US15/612,321
• Publication Number:
  US 20170349230A1
• Time in Patent Office: 277 Days
• CPC Class Codes: A63C 17/014 Wheel arrangements
• CPC Class Codes: A63C 17/016 with wheels arranged in one track
• CPC Class Codes: A63C 17/08 single-wheel type with single axis
• CPC Class Codes: A63C 17/12 with driving mechanisms
• CPC Class Codes: A63C 17/26 with special auxiliary arrangements, e.g. illuminating, marking, or push-off devices
• CPC Class Codes: A63C 2203/12 Electrically powered or heated
• CPC Class Codes: 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
• CPC Class Codes: B60L 2200/14 Vehicles with one wheel only
• CPC Class Codes: B60L 2200/16 Single-axle vehicles
• CPC Class Codes: B60L 2200/24 Personal mobility vehicles
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/42 related to electric machines
• CPC Class Codes: B60L 2250/22 by presence detection
• CPC Class Codes: B62J 45/41 characterised by the type of sensor
• CPC Class Codes: B62J 45/42 characterised by mounting
• CPC Class Codes: B62K 11/007 Automatic balancing machines with single main ground engaging wheel or coaxial wheels supporting a rider
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An electric vehicle may include a board having two deck portions each configured to receive a foot of a rider, and a wheel assembly disposed between the deck portions. A motor assembly may drive the wheel assembly in response to board orientation and rider presence information. A rider detection mechanism may include one or more strain gauges, and may be configured to detect rider presence and rider weight information. A responsiveness of the motor may be automatically adjusted based on the rider weight information.

Claims

1. An electric vehicle comprising:

a board including first and second deck portions each configured to receive a left or right foot of a rider oriented generally perpendicular to a longitudinal centerline of the board;

a wheel assembly including a ground-contacting element disposed between and extending above the first and second deck portions;

a motor assembly mounted to the board and configured to rotate the ground-contacting element around an axle to propel the electric vehicle;

at least one orientation sensor configured to measure orientation information of the board;

a first strain gauge and a second strain gauge spaced apart across the longitudinal centerline of the board and configured to produce rider presence information and rider weight information; and

a motor controller in communication with the motor assembly, the motor controller configured to receive the orientation information and the rider presence information, and to cause the motor assembly to propel the electric vehicle based on the board orientation information and the rider presence information;

wherein the motor controller is configured to determine a weight category of the rider based on the rider weight information, and to respond automatically to the orientation information with a selected aggressiveness based on the rider weight category, such that a same board orientation results in a different acceleration response depending on the rider weight category.

2. The electric vehicle of claim 1, wherein the selected aggressiveness of the motor controller response is selectable by the user.

3. The electric vehicle of claim 1, wherein the selected aggressiveness of the motor controller is associated with a Proportional-Integral-Derivative (PID) loop.

4. The electric vehicle of claim 1, wherein the selected aggressiveness of the motor controller is associated with a current-resistance (IR) compensation circuit.

5. The electric vehicle of claim 1, wherein the ground contacting element extends laterally across at least a majority of a width of the board.

6. The electric vehicle of claim 1, wherein the first and second deck portions are formed as a single piece.

7. The electric vehicle of claim 1, wherein the first and second strain gauges are each disposed on the second deck portion.

8. The electric vehicle of claim 1, wherein the first and second strain gauges each comprise a respective full-bridge strain gauge circuit.

20. The electric vehicle of claim 1, wherein the motor controller is configured to respond to different rider weight categories with different respective acceleration response curves.

9. A self-balancing electric vehicle comprising:

a board having a first deck portion and a second deck portion, collectively defining a plane and having a longitudinal axis, the first deck portion configured to support a first foot of a rider oriented generally perpendicular to the longitudinal axis, the second deck portion configured to support a second foot of the rider oriented generally perpendicular to the longitudinal axis;

a wheel mounted to the board between the deck portions, extending above and below the plane and configured to rotate about an axle coupled to the board;

an orientation sensor coupled to the board and configured to sense orientation information of the board;

a first strain gauge load cell and a second strain gauge load cell spaced apart across the longitudinal axis of the board, such that the first and second strain gauge load cells sense a strain applied to the board and are configured to produce rider presence information and rider weight information based on the sensed strain;

a motor controller configured to receive the orientation information and the rider presence information, and to generate a motor control signal in response; and

a motor configured to receive the motor control signal from the motor controller and to rotate the wheel in response, thereby propelling the electric vehicle;

wherein the motor controller is further configured to determine a weight category of the rider based on the rider weight information, and to adjust the motor control signal based on the weight category, such that a same board orientation results in a different acceleration response depending on the rider weight category.

10. The electric vehicle of claim 9, wherein the first strain gauge load cell comprises a full-bridge strain gauge circuit.

11. The electric vehicle of claim 9, wherein the first strain gauge load cell and the second strain gauge load cell are disposed on the second deck portion.

12. The electric vehicle of claim 9, wherein the first deck portion is coupled to the second deck portion by a rigid frame.

13. The electric vehicle of claim 12, wherein the rigid frame, the first deck portion, and the second deck portion are formed as a single piece.

14. The electric vehicle of claim 9, wherein the wheel extends laterally across at least a majority of a width of the board.

15. An electric skateboard comprising:

a foot deck having first and second deck portions each configured to support a rider'"'"'s foot oriented generally perpendicular to a longitudinal axis of the foot deck;

exactly one ground-contacting wheel disposed between and extending above the first and second deck portions and configured to rotate about an axle to propel the electric skateboard;

at least one orientation sensor configured to measure an orientation of the foot deck;

a first strain gauge load cell and a second strain gauge load cell spaced apart across the longitudinal axis of the foot deck, such that the first and second strain gauge load cells sense a strain applied to the foot deck and are configured to produce rider presence information and rider weight information based on the sensed strain; and

an electric motor configured to cause rotation of the ground contacting wheel based on the orientation of the foot deck and the rider presence information;

wherein the electric motor is further configured to determine a weight category of the rider based on the rider weight information, and to adjust a responsiveness characteristic based on the weight category, such that a same foot deck orientation results in a different acceleration response depending on the rider weight category.

16. The electric skateboard of claim 15, wherein the first strain gauge load cell comprises a full-bridge strain gauge circuit.

17. The electric skateboard of claim 15, wherein the foot deck is formed as a single piece.

18. The electric skateboard of claim 15, wherein the responsiveness characteristic corresponds to a change in a voltage applied to the electric motor for a given change in the orientation of the foot deck.

19. The electric skateboard of claim 18, wherein the responsiveness characteristic is proportional to the rider weight information.