Mobility device control system
First Claim
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1. A mobility device control system comprising:
- at least one user control device receiving desired actions for the mobility device;
at least one power base controller operably coupled with the at least one user control device, the at least one power base controller receiving the desired actions from the at least one user control device, the at least one power base controller including at least two processors, the at least two processors each including at least one controller processing task, the at least one controller processing task receiving sensor data and motor data associated with sensors, wheels, and motors operably coupled with the mobility device; and
at least one inertial measurement unit (IMU) operably coupled with the at least one power base controller, the at least one IMU producing an inertial estimate, the inertial estimate based at least on filtering data from the at least one IMU, the at least one IMU including a rate sensor and an accelerometer, the filtering including(a) receiving and filtering a gravity vector of the mobility device from the accelerometer, the filtering based at least on a gravity rate,(b) receiving and filtering a body rate vector of the mobility device from the rate sensor, the filtering based at least on a gravity rate error and a projected body rate error,(c) receiving a differential wheel speed representing the difference in speed of each of the at least two wheels;
(d) estimating a projected gravity rate based at least on the filtered gravity vector and the filtered body rate vector;
(e) computing the projected body rate error based at least on the projected gravity rate and the differential wheel speed;
(f) computing a pitch and a roll based at least on the filtered measured body rate and the filtered gravity vector; and
(g) repeating steps (a)-(f) using the computed projected body rate error;
the inertial estimate used to compute a pitch and a roll of the mobility device,wherein the at least two processors compute values based at least on the desired actions, the sensor data, the motor data, the pitch and the roll of the mobility device, the values being provided to the wheels to control the motion of the mobility device.
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Abstract
A mobility device that can accommodate speed sensitive steering, adaptive speed control, a wide weight range of users, an abrupt change in weight, traction control, active stabilization that can affect the acceleration range of the mobility device and minimize back falls, and enhanced redundancy that can affect the reliability and safety of the mobility device.
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Citations
18 Claims
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1. A mobility device control system comprising:
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at least one user control device receiving desired actions for the mobility device; at least one power base controller operably coupled with the at least one user control device, the at least one power base controller receiving the desired actions from the at least one user control device, the at least one power base controller including at least two processors, the at least two processors each including at least one controller processing task, the at least one controller processing task receiving sensor data and motor data associated with sensors, wheels, and motors operably coupled with the mobility device; and at least one inertial measurement unit (IMU) operably coupled with the at least one power base controller, the at least one IMU producing an inertial estimate, the inertial estimate based at least on filtering data from the at least one IMU, the at least one IMU including a rate sensor and an accelerometer, the filtering including (a) receiving and filtering a gravity vector of the mobility device from the accelerometer, the filtering based at least on a gravity rate, (b) receiving and filtering a body rate vector of the mobility device from the rate sensor, the filtering based at least on a gravity rate error and a projected body rate error, (c) receiving a differential wheel speed representing the difference in speed of each of the at least two wheels; (d) estimating a projected gravity rate based at least on the filtered gravity vector and the filtered body rate vector; (e) computing the projected body rate error based at least on the projected gravity rate and the differential wheel speed; (f) computing a pitch and a roll based at least on the filtered measured body rate and the filtered gravity vector; and (g) repeating steps (a)-(f) using the computed projected body rate error; the inertial estimate used to compute a pitch and a roll of the mobility device, wherein the at least two processors compute values based at least on the desired actions, the sensor data, the motor data, the pitch and the roll of the mobility device, the values being provided to the wheels to control the motion of the mobility device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling a mobility device, the mobility device including at least one user control device, at least one a power base controller having at least two processors, the at least two processors each having at least one controller processing task, at least one sensor, at least two wheels controlled by at least two motors, and at least one inertial measurement unity (IMU) having an IMU accelerometer and an IMU rate sensor, the method comprising:
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receiving desired actions for the mobility device; receiving, by the at least one controller processing task, sensor data from the at least one sensor, and motor data from the at least one motor; filtering data from the at least one IMU, the at least one IMU including a rate sensor and an accelerometer, the filtering including (a) receiving and filtering a gravity vector of the mobility device from the accelerometer, the filtering based at least on a gravity rate, (b) receiving and filtering a body rate vector of the mobility device from the rate sensor, the filtering based at least on a gravity rate error and a projected body rate error, (c) receiving a differential wheel speed representing the difference in speed of each of the at least two wheels; (d) estimating a projected gravity rate based at least on the filtered gravity vector and the filtered body rate vector; (e) computing the projected body rate error based at least on the projected gravity rate and the differential wheel speed; (f) computing a pitch and a roll based at least on the filtered measured body rate and the filtered gravity vector; and (g) repeating steps (a)-(f) using the computed projected body rate error; computing, by each of the at least one controller processing tasks, at least one value based at least on the desired actions, the sensor data, the motor data, the pitch, and the roll; and applying the at least one value to at least one of the at least two wheels to control the mobility device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for controlling the rearwards pitch rate of a mobility device when the mobility device hits an obstacle while in motion, the mobility device including at least one user control device, at least one a power base controller having at least two processors, the at least two processors each having at least one controller processing task, at least one sensor, and at least two wheels controlled by at least two motors, the method comprising:
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computing, by the at least one controller processing task, a stabilization parameter based at least on a measured pitch angle, a desired fore-aft velocity, a measured pitch rate and a desired pitch rate, the desired fore-aft velocity and the desired pitch rate being received by the at least one user control device, the measured pitch angle and the measured pitch rate being received by the at least one sensor; computing, by the at least one controller processing task, a dynamic metric based at least on the measured pitch angle, the measured pitch rate, and a measured distance the mobility device moved since over a pre-selected time period, the measured distance being received by the at least one sensor; computing, by the at least one controller processing task, a modified control signal by applying the stabilization parameter to a fore-aft control signal output from a PID controller having inputs of the desired fore-aft velocity and a measured fore-aft velocity if the dynamic metric meets pre-selected criteria, the measured fore-aft velocity being received by the at least one sensor; computing, by the at least one controller processing task, a voltage command for the at least two wheels based at least on the modified control signal; and providing, by the at least one controller processing task, the voltage command to the at least two motors to control the at least two wheels.
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Specification