US 10,806,649 B1 · Enhanced mobility wheelchair

Abstract

An enhanced mobility wheelchair with semi-autonomous control logic includes criteria for selecting level, stair, and slope modes. Each mode progresses through criteria-invoked phases as the wheelchair travels. Each axis performs an assigned duty for each mode and phase combination to seek a defined target. Control logic invokes stair mode from the level mode when steps are sensed. Criteria restricts negotiating obstacle angles and heights encountered beyond capability and permits reversed travel to exit obstacle. Front and rear support systems include the ability to sense both forward and backward facing steps by adding distance sensors, sensing linkage and rotary sensors. Legrest adjustment raises the feet for forward step climbing and shortens the wheelchair length for tight turns. Steep down slope and steep up slope modes are invoked from a small angle slope mode. Absolute measurement of spider rotation and spider cam engagement does not require adjustment.

A motorized vehicle with means to invoke a stair-climbing mode from a normal level mode when encountering step obstacles comprising:

A. a frame;
B. a LEVEL mode (MLL) comprising a default condition of operation adapted for a substantially horizontal surface;
C. a STAIR mode (MSL) comprising a stair-climbing mode adapted for single or multiple step-climbing;
D. a front balancing means or a skid system comprising an actuating means, a skid wheel pair, and a skid runner pair;
said skid runner comprising articulating and biasing means;
E. a rear balancing means or a caster system comprising an actuating means, a caster wheel or caster wheel pair, and a caster runner pair;
said caster runner comprising articulating and biasing means;
F. a spider system comprising a wheel cluster or a spider rotably mounted to the left and right side of said frame;
said spider system further comprising a plurality of drive wheels mounted to spider spokes about a central axis;
a spider system rotation means comprising a motor rotationally linked to said spider pair by a common shaft;
a front drive wheel comprising a lower forward drive wheel;
a rear drive wheel comprising a lower aft drive wheel;
a spider pitch control duty (SPD_PC) comprising spider rotation with four drive wheels resting on a surface and targeting a pitch target (PTC_TG);
G. a spider cam comprising one step engaging surface for each drive wheel;
said spider cam rotary axis parallel to the spider system central axis and located aft of said spider central axis;
where said spider cam contacting a step edge causes said spider cam to rotate relative to said spider spokes;
H. a control system comprising sensors, algorithms, and motor controls;
I. a plurality of sensing means comprising;
a. a skid system position sensing means comprising a skid system position rotary sensor;
a skid system angle (SKD_ANG);
a skid system full up position indication (SKD_UP) comprising a zero said skid system angle (SKD_ANG) at the full up position;
a low skid system indication (SKD_LOW) comprising said skid system angle (SKD_ANG) consistent with said skid wheel pair below a step landing;
b. a caster runner engagement sensing means comprising a rotary sensor monitoring deflection of said caster runner;
a caster runner engagement value (CSLA_EMT and CSRA_EMT) comprising a caster runner engagement sensing reading measured from the undeflected position;
a caster runner engagement range comprising full deflection of said caster runner to a stop;
a caster runner supporting indication (CST_RN_SUPT) comprising said caster runner engagement value (CSLA_EMT and CSRA_EMT) equal to caster runner engagement range;
a caster runner engaged indication (CST_RN_ENGD) comprising a positive said caster runner engagement value (CSLA_EMT and CSRA_EMT);
c. a spider rotation angle sensing means comprising a rotary sensor rotationally linked to said spider system;
a spider system angle (SD_ANG) comprising an angle measured from an aft frame horizontal line relative to the centerline of the nearest lower spoke centerline;
a lower drive wheels horizontal indication (SPDR_ON_STP) comprising a predetermined range of said spider system angle (SD_ANG) range values with lower said drive wheel pairs substantially parallel to a notional frame horizontal plane;
a 4-wheel drive spider angle range (SPDR_4WD) comprising a predetermined range of said spider system angle (SD_ANG) range values for spider negotiating up and down step with two lower drive wheels;
d. a spider cam angle sensing means comprising a rotary sensor rotationally linking said spider cam to said frame;
a spider cam angle (SL_ANG or SR_ANG) consistent with spider angle when said spider cam is undeflected;
a spider crowd engagement value (CWD_LFT or CWD_RHT) comprising said spider system angle (SD_ANG) minus said spider cam angle (SL_ANG or SR_ANG);
a spider cam engaged indication (SPDR_ENGD) comprising a positive said spider crowd engagement value (CWD_LFT or CWD_RHT);
e. a motor drive velocity signal comprising a voltage or PWM signal from a motor drive;
a vehicle advancing indication (ADV) comprising a motor drive velocity signal range consistent with the vehicle advancing;
a vehicle backing indication (BCK) comprising a second motor drive velocity signal range consistent with the vehicle backing;
f. a caster wheel height sensing means comprising a distance sensor mounted on a caster wheel bogie or mount adjacent to said caster wheel and aimed down;
a caster wheel height sensor reading (CWT_RD);
a caster wheel-to-step height (CWT_HT) comprising said caster wheel height sensor reading (CWT_RD) minus the vertical distance from the sensor to the caster wheel lower surface;
a wheel engagement range (W_EN_RG) comprising a small predetermined height;
a caster wheel engagement value (CWT_EMT) comprising said wheel engagement range (W_EN_RG) minus caster wheel-to step height;
a caster wheel engaged indication (CWT_ENGD) comprising a positive said caster wheel engagement value (CWT_EMT);
a caster wheel supporting indication (CWT_SUPT) comprising said caster wheel engagement value (CWT_EMT) equal to said wheel engagement range (W_EN_RG);
g. a forward step height sensing means comprising a distance sensor attached to a bogie or mount for said skid wheel and aimed down and forward of the said motorized vehicle;
a forward step height sensor reading (KLFT_RD or KRFT_RD);
a skid wheel-to-forward step height (KLFT_HT or KRFT_HT) comprising a vertical distance from said sensor to a surface below said skid wheel subtracted from said forward step height sensor reading (KLFT_RD or KRFT_RD);
a forward step engagement value (KLFT_EMT or KRFT_EMT) comprising said skid wheel-to-forward step height (KLFT_HT or KRFT_HT) subtracted from said wheel engagement range (W_EN_RG);
a forward step engaged indication (KFT_ENGD) comprising a positive said forward step engagement value (KLFT_EMT or KRFT_EMT) and said vehicle advancing indication (ADV);
h. a skid wheel height sensing means comprising a distance sensor mounted on a skid wheel mount adjacent to said skid wheel and aimed down;
a skid wheel height sensor reading (KWT_RD);
a skid wheel-to-step height (KWT_HT) comprising said skid wheel height sensor reading (KWT_RD) minus the vertical distance from the sensor to below said skid wheel;
a skid wheel engagement value (KW_EMT) comprising said wheel engagement range (W_EN_RG) minus said skid wheel-to-step height (KWT_HT);
a skid wheel supporting indication (KWT_SUPT) comprising said skid wheel engagement value (KW_EMT) equal to said wheel engagement range (W_EN_RG);
i. a skid runner engagement sensing means comprising a rotary sensor monitoring deflection of said skid runner;
a skid runner engagement value (KGLA_EMT or KGRA_EMT) comprising a sensor reading measured from the undeflected position;
a skid runner supporting indication (SKD_RN_SUPT) comprising said skid runner engagement value (KGLA_EMT or KGRA_EMT) consistent with full runner deflection travel;
j. a skid system engagement value (SKD_EMT) comprising the maximum value of said skid runner engagement value (KGLA_EMT or KGRA_EMT), said forward step engagement value (KLFT_EMT or KRFT_EMT), and skid wheel engagement value (KW_EMT);
a skid engagement target (SKD_EN_TG) comprising a predetermined mid-range said skid system engagement value (SKD_EMT);
k. a wheelchair forward step height value (WF_HT) comprising largest of said skid wheel-to-forward step height (KLFT_HT or KRFT_HT) minus said skid wheel-to-step height (KWT_HT);
(WF_HT=KLFT_HT−KWT_HT) or
(WF_HT=KRFT_HT−KWT_HT);
l. a skid system advancing and approaching a forward facing down step indication (SKD_APR_FUS) comprising said vehicle advancing indication (ADV) and a negative said wheelchair forward step height value (WF_HT) less than a predetermine value consistent with the operational limit for normal level travel;
m. a skid system advancing to a forward facing up step indication (SKD_APR_FUS) comprising said vehicle advancing indication (ADV) and said wheelchair forward step height value (WF_HT) greater than a predetermine value consistent with the operational limit for normal level travel and said vehicle advancing indication (ADV);
n. a front drive wheels height sensing means comprising a distance sensor mounted on said frame adjacent to said front drive wheels and aimed down;
a front drive wheels-to-step sensor reading (LFDW_RD or RFDW_RD) comprising the distance below said front drive wheels height sensing means to a surface;
a front drive wheels-to-step height (FDW_HT) comprising a height below said front drive wheels to a surface computed from a function of front drive wheels sensor installation geometry, spider spoke geometry, drive wheel geometry, said spider system angle (SD_ANG) and said front drive wheels-to-step sensor reading (LFDW_RD or RFDW_RD);
a front drive wheels engagement value (FDW_EMT) comprising said wheel engagement range (W_EN_RG) minus said front drive wheels-to-step height (FDW_HT);
a front drive wheels supporting indication (FDW_SUPT) comprising said front drive wheels engagement value equal to said wheel engagement range (W_EN_RG) (FDW_EMT=W_EN_RG);
o. a rear drive wheels height sensing means comprising a distance sensor mounted on said frame adjacent to said rear drive wheels and aimed down;
a rear drive wheels-to-step sensor reading (RDW_RD) comprising the distance below said rear drive wheels height sensing means to a surface;
a rear drive wheels-to-step height (RDW_HT) comprising a height below said rear drive wheels to a surface computed from a function of rear drive wheels sensor installation geometry, spider spoke geometry, drive wheel geometry, said spider system angle (SD_ANG) and said rear drive wheels-to-step sensor reading (RDW_RD);
a rear drive wheels engagement value (RDW_EMT) comprising said wheel engagement range (W_EN_RG) minus said rear drive wheels-to-step height (RDW_HT);
a rear drive wheels supporting indication (RDW_SUPT) comprising rear drive wheels engagement value (RDW_EMT) equal to said wheel engagement range (W_EN_RG);
p. a rear step height sensing means comprising a distance sensor attached to a bogie or mount for said caster wheel and aimed down and behind said motorized vehicle;
a rear step height sensor reading (RSTP_RD);
a wheelchair rear step height value (WR_HT) comprising said rear step height sensor reading (RSTP_RD) minus a vertical distance from said sensor to a surface below the underside of said caster wheel plus said caster wheel-to-step height (CWT_HT);
q. a caster system backing toward a forward facing up step indication (CST_APR_FUS) comprising said vehicle backing indication (BCK) and said wheelchair rear step height value (WR_HT) consistent with a small predetermined height below said caster wheel;
J. a LEVEL mode request switch (QLL);
an algorithm for invoking said LEVEL mode (MLL) comprising a request by said LEVEL mode request switch (QLL) and said lower drive wheels horizontal indication (SPDR_ON_STP);
K. an algorithm for invoking said STAIR mode (MSL) from said LEVEL mode (MLL) comprising:
a. said spider cam engaged indication (SPDR_ENGD),
b. not said 4-wheel drive spider angle range (not SPDR_4WD),
c. said skid system advancing to a forward facing up step indication (SKD_APR_FUS),
d. said skid system advancing and approaching a forward facing down step indication (SKD_APR_FDS),
e. said caster system backing toward a forward facing up step indication (CST_APR_FUS), or
f. said caster runner engaged indication (CST_RN_ENGD);
whereby said motorized vehicle will accept a request for level travel if appropriate or automatically switch to stair-climbing when indicated.

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Enhanced mobility wheelchair

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Enhanced mobility wheelchair

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Abstract

Claims18