Motorized wheelchairs
AssigneeInvacare Corporation
InventorsJoseph B. Richey, II, Theodore D. Wakefield, II
Life of this patent
Estimating the term…
Abstract
A motorized wheelchair is advantageously provided with a rate-of-turn feedback sensor and with forward/reverse motion, lateral motion, and vertical motion acceleration feedback sensors that are integrated into a closed-loop wheelchair servo control system to differentially control the rotational speed of wheelchair opposed motor-driven wheels and thereby obtain improved wheelchair motion stability through reduction/elimination of likely wheelchair spin-out and wheelchair tipping during wheelchair operation.
Claims31
In a method of controlling motion of a motorized wheelchair assembly having separately-controlled, motor-driven right and left wheels that provide wheelchair assembly rolling support, the steps of:
- providing turn direction command inputs and turn rate command inputs to the motorized wheelchair assembly to cause correlated wheelchair motion;
- sensing the actual turn direction and actual angular rate-of-turn of said motorized wheelchair assembly;
- comparing said sensed wheelchair assembly actual turn direction and angular rate-of-turn signals with wheelchair assembly provided turn direction and turn rate command inputs and developing their respective differences as control signals;
- utilizing said developed control signals to regulate differential rotation of said motorized wheelchair assembly motor-driven right and left wheels to thereby limit wheelchair actual rate-of-turn magnitude to a predetermined magnitude not exceeding the magnitude of said wheelchair assembly turn rate command input;
- and
- upon the failure to sense the actual turn direction and actual angular rate-of-turn of said motorized wheelchair assembly generating a maximum forward velocity to thereby limit wheelchair actual forward velocity.
A method of controlling a motorized wheelchair assembly, having a right motor-driven wheel and a left motor-driven wheel, comprising the steps of:
- a) generating a first driving signal for driving the right motor-driven wheel and a second driving signal for driving the left motor-driven wheel;
- b) generating a wheelchair turn direction command signal and a wheelchair linear velocity command signal;
- c) sensing actual turn directions of the wheelchair and generating an actual turn direction signal;
- d) sensing actual turn rate and generating an actual turn rate signal;
- e) comparing said wheelchair turn direction and linear velocity command signals to said actual turn direction and actual turn rate signals;
- f) as a result of said comparison step modifying at least one of the first or second driving signals;
- and
- g) upon the detection of a failure to sense the actual turn rate, limiting the linear velocity command signal to a maximum value.
A method of controlling a motorized wheelchair assembly, having a right driven wheel and a left motor-driven wheel comprising the steps of:
- a) generating a turn command input signal and a linear velocity command signal;
- b) sensing actual angular rates of turn of the wheelchair and generating a corresponding first actual rate-of-turn signal;
- c) sensing the first actual rate-of-turn signal;
- d) comparing said turn command input signal and the first actual rate-of-turn signal;
- e) in response to said comparison step, regulating differential rotation of the motor-driven right and left wheels;
- and
- f) upon the failure to sense the first actual rate-of-turn signal, limiting the linear velocity command signal to a maximum value.
A method of controlling a motorized wheelchair assembly, having a right motor-driven wheel and a left motor-driven wheel, comprising the steps of:
- a) generating a first driving signal for driving the right motor-driven wheel and a second driving signal for driving the left motor-driven wheel;
- b) generating a wheelchair turn direction command signal and a wheelchair linear velocity command signal;
- c) sensing actual turn directions of the wheelchair and generating an actual turn direction signal;
- d) sensing actual turn rate and generating an actual turn rate signal;
- e) comparing said wheelchair turn direction and linear velocity command signals to said actual turn direction and actual turn rate signals;
- and
- f) as a result of said comparison step modifying at least one of the first or second driving signals.
A method of controlling a motorized wheelchair assembly, having a right driven wheel and a left motor-driven wheel comprising the steps of:
- a) generating a turn command Input signal and a linear velocity command signal;
- b) sensing actual angular rates of turn of the wheelchair and generating a corresponding actual rate of turn signal;
- c) comparing said turn command input signal and the actual rate of turn signal;
- and
- d) in response to said comparison step, regulating differential rotation of the motor-driven right and left wheels.
A method of controlling a motorized wheelchair, having first and second driven wheels, comprising the steps of:
- a) generating a first driving signal for driving the first driven wheel;
- b) generating a second driving signal for driving the second driven wheel;
- c) generating turn and linear acceleration input signals;
- d) sensing forward, vertical, and lateral acceleration of the wheelchair and generating corresponding forward, vertical and lateral acceleration signals;
- e) sensing an angular rate of turn of the wheelchair and generating an actual rate of turn signal;
- f) comparing the linear acceleration input signal to said forward acceleration signal, and as a result of such comparison adjusting the first and second driving signals;
- g) comparing the turn acceleration signal to the actual rate of turn signal, and generating a turn compensation signal as a result of such comparison;
- and
- h) utilizing said turn compensation signal to decrease the first driving signal while increasing the second driving signal.
In a method of controlling motion of a motorized wheelchair assembly having separately-controlled, motor-driven right and left wheels that provide wheelchair assembly rolling support, the steps of:
- providing turn direction command inputs and turn rate command inputs to the motorized wheelchair assembly to cause correlated wheelchair motion;
- sensing the actual turn direction and actual angular rate-of-turn of said motorized wheelchair assembly;
- comparing said sensed wheelchair assembly actual turn direction and angular rate of turn signals with wheelchair assembly provided turn direction and turn rate command inputs and developing their respective differences as control signals;
- and
- utilizing said developed control signals to regulate differential rotation of said motorized wheelchair assembly motor-driven right and left wheels to thereby limit wheelchair actual rate-of-turn magnitude to a predetermined magnitude not exceeding the magnitude of said wheelchair assembly turn rate command input.
Dependencies are inferred from the claim text.