Control of a personal transporter based on user position
An apparatus controller for prompting a rider to be positioned on a vehicle in such a manner as to reduce lateral instability due to lateral acceleration of the vehicle. The apparatus has an input for receiving specification from the rider of a desired direction of travel, and indicating means for reflecting to the rider a propitious instantaneous body orientation to enhance stability in the face of lateral acceleration. The indicating may include a handlebar that is pivotable with respect to the vehicle and that is driven in response to vehicle turning.
1. A method for controlling a transporter, the transporter having at least one ground-contacting element, a handlebar supported by the at least one ground-contacting element, and a controller operatively communicating with the at least one ground-contacting element, the method comprising:
receiving, by the controller, a desired yaw and a desired yaw rate, the desired yaw and the desired yaw rate being based on a body orientation of a load on the transporter;
computing, by the controller, a desired direction of motion of the transporter based on the received desired yaw and the received desired yaw rate;
receiving, by the controller, a pitch of the transporter;
computing, by the controller, a pitch command signal based on the pitch;
computing, by the controller, a command signal based on the desired direction and the pitch command signal; and
providing, by the controller, the command signal to maintain balance of the transporter and motion in the desired direction.
2. The method as in claim 1 further comprising:
computing, by the controller, the command signal based on the body orientation and roll of the transporter sensed by a plurality of sensors in electronic communication with the controller, the command signal modified by a deadband.
3. The method as in claim 1 further comprising:
computing, by the controller, the command signal based at least in part on a yaw error value, the yaw error value being the difference between an instantaneous yaw value and the desired yaw.
4. The method as in claim 1 further comprising:
receiving, by the controller, a lean of the transporter with respect to gravity; and
computing, by the controller, the command signal K(φ HB −φ Roll ) where K=a constant, φ HB =an angle between the handlebar and the ground-contacting element, and φ Roll =the received lean.
5. The method as in claim 1 wherein the handlebar comprises an inclined or horizontally mounted pivot handlebar.
6. The method as in claim 1 wherein the handlebar is biased to a central position by at least one damper.
7. The method as in claim 1 further comprising:
receiving, by the controller, a rotational orientation of the handlebar; and
computing, by the controller, the desired direction based at least in part on the rotational orientation.
8. The method as in claim 1 further comprising:
computing, by the controller, a yaw component of the command signal by:
applying a first gain to the yaw component of the command signal at a first range of speeds; and
applying a second gain to the yaw component of the command signal at a second range of speeds.
9. The method as in claim 1 further comprising:
filtering, by the controller, a yaw component of the command signal based on a roll rate of the transporter.
10. The method as in claim 1 further comprising:
low-pass filtering, by the controller, the desired yaw if a roll rate of the transporter is greater than a pre-selected rate.
11. The method as in claim 10 further comprising:
computing, by the controller, a yaw component of the command signal based on F*(the desired yaw)+(1×F)*(the filtered desired yaw) where F=a continuously varying signal.
12. A system for controlling a transporter, the system comprising:
at least one ground-contacting element;
a handlebar supported by the at least one ground-contracting element; and
a controller operatively communicating with the at least one ground-contacting element, the controller including:
receiving a desired yaw and a desired yaw rate of the transporter, the desired yaw and the desired yaw rate being based on a body orientation of a load on the transporter;
computing a desired direction of motion of the transporter based on the received desired yaw and the received desired yaw rate;
receiving a pitch of the transporter;
computing a pitch command signal based on the pitch;
computing a command signal based on the desired direction and the pitch command signal; and
providing the command signal to maintain balance of the transporter and motion in the desired direction.
13. The system as in claim 12 wherein the controller further includes:
computing, by the controller, the command signal based on the body orientation and roll of the transporter sensed by a plurality of sensors in electronic communication with the controller, the command signal modified by a deadband.
14. The system as in claim 12 wherein the controller further includes:
executing a ramp function reversing a yaw command component of the command signal when the transporter moves in reverse.
15. The system as in claim 12 wherein the controller further includes:
receiving a lean of the transporter with respect to gravity; and
computing the command signal K(φ HB −φ Roll ) where K=a constant, φ HB =an angle between the handlebar and the at least one ground-contacting element, and φ Roll =the received lean.
16. The system as in claim 12 wherein the controller further includes:
computing a yaw component of the command signal by
applying a first gain to the yaw component of the command signal at a first range of speeds; and
applying a second gain to the yaw component of the command signal at a second range of speeds.
17. The system as in claim 12 wherein the controller further includes:
receiving, from shaft sensors, the position of the handlebar with respect to vertical, or with respect to a direction fixed with respect to at least a portion of the transporter.
18. The system as in claim 12 wherein the controller further includes:
filtering a yaw component of the command signal based on a roll rate of the transporter.
19. The system as in claim 12 wherein the controller further includes:
low-pass filtering the desired yaw if a roll rate of the transporter is greater than a pre-selected rate.
20. The system as in claim 11 wherein the controller further comprises:
receiving a relative height offset of at least one handlebar segment disposed upon the transporter, the desired direction based at least in part on the relative height offset.