DE102016217880A1 - Methods and devices for the track rehabilitation of a power assisted wheelchair - Google Patents

Abstract

The method for tracking stabilization includes detecting a current actual yaw rate about the vertical axis of the wheelchair and determining a target yaw rate. The desired yaw rate represents a direction or lane specification of the wheelchair user for the drive of the wheelchair. Depending on the detected actual yaw rate and the determined target yaw rate, a control difference is calculated. The control difference represents a deviation of the wheelchair from the track specified by the wheelchair user. Subsequently, the motor torque of the at least one motor is adjusted as a function of the calculated control difference, whereby the calculated control difference is reduced. Accordingly, the described method changes the engine torque of the engine as a function of the calculated control difference, for example in the case of surfaces having different surface conditions on the first drive wheel and on the second drive wheel, so that the wheelchair moves according to the lane specification of the wheelchair user or the desired yaw rate.

Description

The present invention relates to a method for the tracking stabilization of a power assisted wheelchair and to a control device which is adapted to carry out the method. Moreover, the invention relates to a wheelchair with the control unit.

State of the art

In Scripture EP 0 790 049 A2 is a wheelchair described. A control device of the wheelchair is adapted to calculate a power assist by a motor for a drive wheel of the wheelchair as a function of the manual force on both drive wheels of the wheelchair.

In Scripture US 2002/0011361 A1 is described only a motorized wheelchair with a stability control system. The wheelchair includes a motorized right and left drive wheel and an input device, such as a joystick, to generate forward / reverse and rotational commands.

The object of the present invention is to realize a comfortable method for tracking stabilization for a manually and motor-driven wheelchair, wherein the method is intended to stabilize both a grade exit and a cornering. The lane stabilization should be activated in a roll-out phase of the wheelchair and be as inconspicuous as possible.

Disclosure of the invention

To achieve the above object, the method for tracking stabilization comprises detecting a current actual yaw rate about the vertical axis of the wheelchair and determining a target yaw rate. The desired yaw rate represents a predetermined by the wheelchair track or a predetermined rotational behavior of the wheelchair. Depending on the detected actual yaw rate and the determined target yaw rate, a control difference is calculated. The control difference represents a deviation of the wheelchair from the rotational behavior predetermined by the wheelchair user by means of the desired yaw rate. Subsequently, the motor torque of the at least one motor is adjusted as a function of the calculated control difference, whereby the calculated control difference is reduced. Accordingly, the described method changes, for example, in the case of substrates having a different surface finish on a first drive wheel and on a second drive wheel, the engine torque of the at least one motor as a function of the calculated control difference, so that the wheelchair is adjusted by the method according to the lane specification of the wheelchair user or the desired yaw rate is moved. In addition, a wheelchair on a trip across a slope tends to deviate downhill without the procedure. By contrast, by means of the method according to the invention, the wheelchair also rotates on a slope in accordance with the determined target yaw rate and is thereby stabilized with respect to unwanted, downward-directed rotations. The method thus generally reduces the steering corrections to be performed by the wheelchair user or results in a more comfortable ride for the wheelchair user.

Compared to the prior art for power assisted wheelchairs, the present invention particularly shows the direct detection of the actual yaw rate by a sensor. The engine torque is advantageously adjusted so that any track of the wheelchair is stabilized, i. also a cornering.

The present invention also shows, compared with the prior art for motorized wheelchairs, the need for manual wheelchair drive. In addition, a motor-driven wheelchair without motor support is typically automatically braked. Power assisted wheelchairs, on the other hand, have at least one assistive motor torque during the wheelchair user's intervention phase, i. in the period in which the wheelchair user transmits a force to the power transmission device, and / or in the coasting phase, i. in the period in which the wheelchair user exerts no force on a power transmission device on.

In a preferred embodiment of the invention, the adjustment of the engine torque takes place only in the coasting phase of the wheelchair. This ensures that the wheelchair user is not affected by a motor torque in the intervention phase of the wheelchair user on the at least one power transmission device and a very agile, manual driving feel arises.

In a further development of the invention, the determination of the target yaw rate is performed in an intervention phase of the wheelchair user, ie in particular when a manual force of the wheelchair user detected on a drive wheel or acceleration in the forward or reverse direction. This continuation of the wheelchair user during the intervention phase can influence the target yaw rate.

In a further continuation, the desired yaw rate in the coasting phase of the wheelchair changes as a function of time. It is thereby achieved that the desired yaw rate, for example, determined during the intervention phase of the wheelchair user, loses significance during the coasting phase, so that no abrupt change of direction takes place at the beginning of the next intervention phase.

In one embodiment of the invention, a detection of a weight shift of the wheelchair user takes place to the side. In the intervention phase of the wheelchair user and / or the Ausrollphase the wheelchair, the determination of the target yaw rate is performed in dependence of the detected weight shift. There is no need for a joystick to track specification or for specifying the target yaw rate, which for third, the lane specification of the wheelchair user is not or less perceptible and the impression of a manual wheelchair is substantially maintained.

In an alternative embodiment of the invention, a detection of a first force of the wheelchair user on a first power transmission device and / or detection of a second force of the wheelchair user on a second power transmission device. In the engagement phase, the determination of the desired yaw rate is carried out as a function of the detected, first force and / or the detected, second force. Thus, in this embodiment, no joystick is required for lane specification, which for third, the lane specification of the wheelchair user is not or less strongly perceptible and the impression of a manual wheelchair is substantially maintained.

In a further embodiment, a detection of a current speed of the wheelchair is performed. The determination of the desired yaw rate in the engagement phase and / or in the coasting phase additionally takes place as a function of the detected speed. As a result of this refinement, the wheel stabilization of the wheelchair is adapted to different driving situations or speeds. Narrow cornering, which is needed in buildings, are allowed in this embodiment, for example, only at low speeds. Thus, at low speeds, the desired yaw rate is not adjusted or increased, for example. This keeps the cornering agile and at the same time safe. At a high speed, however, the desired yaw rate is preferably greatly reduced. The latter makes incorrect prescriptions of the wheelchair user at high speeds, which in the worst case can lead to tipping over of the wheelchair, unlikely. This embodiment thus increases the ride comfort and driving safety for the wheelchair user.

Optionally, a calculation of a current yaw angle of the wheelchair is carried out, wherein the adaptation of the at least one engine torque is additionally performed as a function of the calculated yaw angle. In this optional embodiment, the adaptation of the engine torque to the track stabilization advantageously takes place more accurately during the grade travel, i. the adaptation or regulation of the engine torque as a function of the control difference occurs early and with a small control variable, so that the track stabilization is less perceptible and comfortable. In a variant of this embodiment, the adaptation of the at least one engine torque as a function of the calculated yaw angle takes place only during the coasting phase.

In an alternative embodiment, a calculation of a current roll angle takes place, wherein the adaptation of the at least one engine torque is additionally carried out as a function of the calculated roll angle. The calculated roll angle represents, for example, an inclination or a position of the wheelchair when driving across the slope. By this configuration, there is the advantage that, for example, an adjustment of the engine torque is such that a downhill on the slope drive wheel is basically driven slightly stronger than a hill upward drive wheel. As a result, undesired cornering across the slope is compensated, in particular in the coasting phase, for a ride of the wheelchair on a slope due to a slope-down force. Preferably, an acceleration of the wheelchair in the adjustment of the engine torque is avoided. This can be achieved by adjusting the engine torque or torques by increasing the engine torque of the downhill drive wheel and reducing the engine torque of the upward drive wheel depending on the calculated roll angle. In a variant of this embodiment, the adaptation of the at least one engine torque depending on the calculated roll angle takes place only during the engagement phase or the coasting phase.

In a further, alternative embodiment, a calculation of a current pitch angle is performed, wherein the adaptation of the at least one engine torque additionally takes place as a function of the calculated pitch angle. Curves or the supporting motor torque in an upwards travel, a downward travel and / or a travel obliquely to the slope as a function of the slope of the slope or the position of the wheelchair can be adapted by this configuration. Thus, for example, when traveling downhill, the desired yaw rate may be reduced over in-plane travel, thereby reducing the likelihood of the wheelchair user slipping out of the wheelchair rack. In a variant of this embodiment, the adaptation of the at least one engine torque as a function of the pitch angle takes place only during the coasting phase.

The control unit has at least one arithmetic unit. The arithmetic unit detects at least one current actual yaw rate about the vertical axis of the wheelchair and determines a target yaw rate. The arithmetic unit also generates at least one control signal for at least one motor, wherein the control signal is adjusted in response to the detected actual yaw rate and the determined target yaw rate to change at least one motor torque generated by a motor. The controller is thus able to perform the method for the tracking stabilization of a power assisted wheelchair.

Preferably, the arithmetic unit detects a first force acting on a first power transmission device of the wheelchair by the wheelchair user and / or a second force of the wheelchair user on the second, opposite, power transmission device, wherein the target yaw rate determined in dependence on the detected first force and / or the second force and / or the control signal is changed as a function of time.

In a preferred embodiment, the generated control signal is changed only in the coasting phase of the wheelchair.

In further embodiments, the arithmetic unit detects the current speed and / or calculates the arithmetic unit the current yaw angle, the current roll angle and / or the current pitch angle of the wheelchair, the control signal depending on the detected speed, the calculated yaw angle, the calculated roll angle and / or the calculated pitch angle is adjusted. In continuations of these embodiments, the control signal is additionally adjusted as a function of the detected speed, the calculated yaw angle, the calculated roll angle and / or the calculated pitch angle only in the intervention phase of the wheelchair user or in the coasting phase of the wheelchair.

Preferably, the arithmetic unit detects a weight shift of the wheelchair user, wherein the arithmetic unit additionally adapts the control signal as a function of the weight shift.

The power-assisted wheelchair has a first drive wheel and / or a second drive wheel, which can each be driven by a manual power transmission device by a force of the wheelchair user. In addition, at least one motor for power-assisted drive of the first drive wheel and / or the second drive wheel are arranged on the wheelchair. The wheelchair preferably comprises a first, right drive wheel and a second, left drive wheel and, per drive wheel, in each case a force transmission device and an electric motor. Preferably, the wheelchair has a battery for the common power supply of both electric motors or the wheelchair, in particular, the battery is an accumulator. Furthermore, the control unit for controlling the at least one motor and at least one sensor for detecting the yaw rate of the wheelchair are arranged on the wheelchair. Preferably, an inertial measuring unit is arranged on the wheelchair. The inertial measuring unit detects both the yaw rate and accelerations and rotation rates in other spatial directions, so that in addition to the yaw rate and the current yaw angle, the current roll angle and / or the current pitch angle of the wheelchair can be detected or calculated by means of a wheelchair arranged inertial measuring unit. The wheelchair is set up to perform a track stabilization procedure.

In one embodiment of the invention, the wheelchair comprises at least one force sensor, wherein the force sensor is adapted to detect the force exerted on a power transmission device force of the wheelchair user. Preferably, there are at least three force sensors per power transmission device, i. at least six force sensors, arranged on a wheelchair. By the force sensor, the force of the wheelchair user can be detected and the target yaw rate can be determined as a function of the at least one detected force.

In a further embodiment, the wheelchair comprises a speed sensor, in particular a reed sensor and / or a GPS sensor.

In a further development, the wheelchair comprises at least one pressure sensor for detecting a weight or a weight shift of the wheelchair user. The at least one pressure sensor is preferably arranged on the wheelchair frame of the wheelchair. Preferably, the wheelchair frame comprises four pressure sensors.

Brief description of the drawings

The present invention will be explained below with reference to preferred embodiments and accompanying drawings.

1a : Wheelchair

1b : Wheelchair with alternative power transmission device

2 : Flowchart of the procedure

3a : Determination of the target yaw rate in the intervention phase

3b : Determination of the target yaw rate in the coasting phase

4 : Control unit

5 : Diagram of the engagement phase and the coasting phase with engine torque curve and target yaw rate profile

embodiments

In 1a is the right side of a wheelchair 100 shown. The wheelchair 100 includes a right, first drive wheel 101 with a first power transmission device 102 , which is designed as a gripping ring. On the not shown, preferably identical, left side of the wheelchair 100 are a second drive wheel 104 and a second power transmission device 105 arranged. The first power transmission device 102 or the second power transmission device 105 is set up to be a manual force of the wheelchair user 150 on the first drive wheel 101 or the second drive wheel 104 to transfer, causing the wheelchair 100 manually by the wheelchair user 150 can be driven. By a force difference between a first force on the first power transmission device 102 and a second force on the second power transmission device 105 can the wheelchair user 150 specify a rotational behavior or a trace of the wheelchair. In addition, the wheelchair points 100 at least one first engine 103 on. The at least one first engine 103 is with the first drive wheel 101 and / or the second drive wheel 104 connected. Preferably, the wheelchair comprises 100 the first engine 103 for generating a first engine torque and a second engine 106 for generating a second motor torque, wherein the first drive wheel 101 with the first engine 103 and the second drive wheel 104 with the second engine 106 connected is. Preferably, the first engine 103 and / or the second engine 106 an electric motor. The control of the first motor 103 and / or the second motor 106 takes place by means of a control unit 108 , The first motor torque and / or the second motor torque drive the first drive wheel in addition to the manually introduced forces 101 and / or the second drive wheel 104 at. There is also a yaw rate sensor 107 on the wheelchair 100 arranged. The yaw rate sensor 107 detects the actual yaw rate Ψ. of the wheelchair 100 , The yaw rate sensor 107 may be, for example, a gyroscope. There may be more sensors 109 and or 110 on the wheelchair 100 be arranged, for example, a speed sensor, a pressure sensor or additional acceleration and / or rotation rate sensors. The at least one first power transmission device 102 and / or the second power transmission device 105 preferably has at least one force sensor for detecting a manual force of the wheelchair user 150 on the first drive wheel 101 and / or the second drive wheel 104 For example, there are three force sensors on each power transmission device 102 and or 105 arranged. Alternatively, the manual power of the wheelchair user 150 by means of a torque sensor in a wheel axle of the first drive wheel 101 and / or the second drive wheel 104 be recorded. The wheelchair 100 includes, as in 1a shown, typically other components, such as a wheelchair frame and at least one front wheel.

The alternative wheelchair 100 out 1b is different from the wheelchair 100 out 1a by another embodiment of the first power transmission device 102 or the second power transmission device 105 (Not shown), which is not executed in this example as a gripping ring, but as a lever device or are. A lever device as the first power transmission device 102 can one at the Axle of the first drive wheel 101 arranged freewheel include. The manual drive by means of a lifting device, for example, by a back and forth movement of the lever by the wheelchair user 150 , creating a first force of the wheelchair user 150 on the first drive wheel 101 is transmitted.

In 2 the flowchart of the method is shown. In the method, by means of the steps 210 to 214 First, the driving behavior of the wheelchair is detected or calculated from sensor data. In the step 210 becomes the actual yaw rate Ψ. of the wheelchair. The detected actual yaw rate Ψ. represents a rotation of the wheelchair about its vertical axis. Optionally, in one step 211 the current speed v of the wheelchair are detected, for example by a further sensor 110 or a GPS speed sensor, a reed sensor and / or an acceleration sensor. In further, optional steps 212 and 213 The current yaw angle Ψ and / or the roll angle Φ of the wheelchair can be calculated. Additionally, in addition, in one step 214 The pitch angle Θ of the wheelchair can be calculated. The calculation of the current yaw angle Ψ, the current roll angle Φ and / or the current pitch angle Θ can be performed by means of sensor data of a gyrometer 107 take place, the gyrometer 107 Acceleration and rotation rate sensors, for example, in the three spatial directions includes (and thus can also capture the current actual yaw rate).

In an optional step 215 is a first, manual force of the wheelchair user on the first power transmission device of the first drive wheel and in a further, optional step 216 a second, manual force of the wheelchair user on the second power transmission device 105 of the second drive wheel detected.

In another, also optional step 217 there is a detection of a weight shift of the wheelchair user. For this purpose, for example, at least two pressure sensors on the wheelchair frame 110 arranged. A pressure difference between the at least two pressure sensors represents the weight transfer of the wheelchair user to the side.

In the step 218 is detected, whether an intervention phase 501 of the wheelchair user or a coasting phase 502 of the wheelchair. The intervention phase 501 of the wheelchair user is when a manual force of the wheelchair user is exerted on a drive wheel. By contrast, the coasting phase is 502 of the wheelchair when no manual power of the wheelchair user is transmitted to a drive wheel. The detection 218 for example, by detecting an acceleration in the forward or reverse direction. Alternatively, the detection takes place 218 the intervention phase 501 depending on the detection 215 a first force of the wheelchair user and / or the detection 216 a second force of the wheelchair user.

The investigation 220 the desired yaw rate Ψ. _S can be done both in the intervention phase of the wheelchair user and in the Ausrollphase the wheelchair. The investigation 220 the desired yaw rate Ψ. _S is carried out, for example, as a function of the detected first force and / or the detected second force. Alternatively, the determination takes place 220 the desired yaw rate Ψ. _S depending on the detected weight transfer of the wheelchair user.

Preferably, in a roll-out phase of the wheelchair, ie when no manual force of the wheelchair user is exerted on a drive wheel, an adaptation 221 the target yaw rate as a function of time performed.

The investigation 220 the desired yaw rate Ψ. _S in the intervention phase can be dependent on a detection 215 the first power of the wheelchair user 150 to the first power transmission device 102 and / or a collection 216 the second power of the wheelchair user 150 to the second power transmission device 105 take place at a time t ₁ , wherein according to a geometry of the wheelchair 100 from the detected first force, a manual, first torque M ₁ and from the detected second force a manual, second torque M ₂ about the vertical axis of the wheelchair 100 be calculated. The time t ₁ preferably represents an end of an engagement phase 501 the wheelchair user on the first power transmission device 102 and / or the second power transmission device 105 , Subsequently, the target yaw rate Ψ. _{S determined} as a function of the difference ΔM between the first torque M ₁ and the second torque M ₂ . The investigation 220 the desired yaw rate Ψ. _S can be done, for example, according to equation (1), wherein a function k is the conversion of the difference ΔM in the target yaw rate Ψ. _S and a dependence of the target yaw rate Ψ. _S of that in the steps 210 - 214 recorded driving behavior describes. The functions k can thus, for example, a dependence of the target yaw rate Ψ. _S of the detected speed v, the calculated yaw angle Ψ, the calculated roll angle Φ and / or the calculated pitch angle Θ have. Ψ. _S = ΔM · k with ΔM = M ₁ - M ₂ (1)

In an alternative embodiment, the determination takes place 220 the desired yaw rate Ψ. _S as a function of an average value of the difference ΔM in the period t ₀ to t ₁ , wherein a start time t _0, for example, a start and an end time t _{1 represent} an end of the intervention phase of the wheelchair user.

In a further refinement, the difference ΔM is integrated from the start time t ₀ to the end time t ₁ according to equation (2), it being possible for a function J to be provided in the integral, which represents a desired inertia behavior of the wheelchair. The function J can additionally depend on the target yaw rate Ψ. _S , the calculated velocity v, the calculated yaw angle Ψ, the calculated roll angle Φ and / or the calculated pitch angle Θ.

In 3a is the further embodiment of the investigation 220 the desired yaw rate Ψ. _S in the engagement phase according to equation (2). A first force and second force of the wheelchair user is detected (not shown). From this, the first torque M ₁ and the second torque M _{2 are} calculated as in FIG 3a shown. In this example, the wheelchair user drives the wheelchair to turn. The difference ΔM is determined from the first torque and the second torque. The target yaw rate Ψ. _S is integrated in this embodiment from the time t ₀ to the time t ₁ . In 3a is also shown that the target yaw rate Ψ. _{S has} a function of the function J, ie for larger function values of the function J results in a more agile driving behavior or narrower radii radii, as for smaller function values of the function J. Thus, the function J describes the inertia of the method to changes in direction and can be dependent on the Target yaw rate Ψ. _S , the calculated velocity v, the calculated yaw angle Ψ, the calculated roll angle Φ and / or the calculated pitch angle Θ.

The wheelchair user is therefore by the detection of manual forces on the power transmission devices 102 and 105 the cornering or the direction of the wheelchair, ie the desired yaw rate Ψ. _S , before, wherein the determination of the target yaw rate Ψ. _S can be done differently.

An alternative, force-independent determination of the desired yaw rate is carried out, for example, by interpretations of detected accelerations and / or rotation rates in the three spatial directions, additional arrow keys, an additional joystick or an additional touchscreen, which is arranged on at least one of the at least one power transmission device or on the wheelchair frame could be. Furthermore, the track specification or the desired yaw rate Ψ. _S by a lateral adjustment of the power transmission device 102 and or 105 be determined. For this purpose, for example, a gripping ring are laterally displaced from or to the drive wheel, wherein the displacement detected by a sensor and the target yaw rate is determined in dependence on the lateral displacement of the gripping ring. In another alternative, the determination of the desired yaw rate Ψ. _S as a function of lateral weight transfer of the wheelchair user done.

In 3b is a diagram to change 221 the desired yaw rate Ψ. _{S shown} in the coasting phase as a function of time, with a preferred reduction of the target yaw rate Ψ. _S is shown over time. Accordingly, the importance of the wheelchair user's lane guidance becomes less important over time, resulting in a steady transition to grade travel with continued coasting. The target yaw rate Ψ. _S is at the beginning of the coasting phase, ie at a time t ₁ , equal to the actual yaw rate Ψ. at the end of the intervention phase. In 3 is also the optional dependency of the change 221 the desired yaw rate Ψ. _{S represented} by a detected speed v. In the illustrated embodiment, the target yaw rate Ψ. _{S is} reduced more strongly for a higher speed v ₂ than for a lower speed v ₁ .

In a subsequent step 230 is a control difference between the determined target yaw rate Ψ. _S and the detected actual yaw rate Ψ. calculated. In other words, the driving desire of the wheelchair user is compared with the driving behavior of the wheelchair.

In a final step 240 an adaptation of the at least one generated engine torque to the power assistance of the wheelchair as a function of the calculated control difference carried out. Preferably, the first engine torque of the first engine and the second engine torque of the second engine are adjusted, wherein the adjustment 240 of the first motor torque and the second motor torque may be equal in magnitude, but with the opposite sign, so that the method for the following does not additionally accelerate or decelerate the wheelchair. Preferably, the adaptation of the first engine torque and the second engine torque takes place only in the coasting phase of the wheelchair.

For example, results from a less adhesive ground on the first, right drive wheel 1a as on the second, left drive wheel (not shown) a right turn of the wheelchair, although the wheelchair user wants to go straight. In the intervention phase 501 of the wheelchair user, the wheelchair user preferably compensates for the different surfaces on the first drive wheel and the second drive wheel manually by a corresponding first force on the first power transmission device and a second force on the second power transmission device. In the coasting phase, the first engine torque or the second engine torque is or are adjusted by the control method so that instead of the right turn results in a degree of wheelchair ride.

The adaptation 240 However, the motor torque or the method can alternatively be performed both in the intervention phase of the wheelchair user, ie when the wheelchair user exerts a force on the power transmission device, as well as in the Ausrollphase the wheelchair, ie when the wheelchair user no longer exerts force on the power transmission device. In one embodiment, the customization becomes 240 the engine torque only in the coasting phase 502 carried out, being in the intervention phase 501 the desired rotational behavior of the wheelchair for tracking stabilization by the determination 220 the desired yaw rate is determined.

In the 4 is the control unit 108 represented, which at least one arithmetic unit 401 includes. The arithmetic unit 401 detected by the yaw rate sensor 107 the current actual yaw rate of the wheelchair around its vertical axis. Optionally, the arithmetic unit 401 additional sensor signals from at least one other sensor 109 , For example, detect accelerations in the three spatial directions and rotation rates to the remaining two spatial axes. The sensor 109 is in particular a gyroscope. The arithmetic unit 401 can by means of the optional sensor signals of the gyroscope 109 calculate the yaw angle, the pitch angle and / or the roll angle. Through the arithmetic unit 401 In addition, the desired yaw rate is determined. The determination of the desired yaw rate during the engagement phase preferably takes place as a function of the detection of the first force on the first force transmission device and as a function of the detection of the second force on the second force transmission device, wherein forces are likewise transmitted by the arithmetic unit 401 be recorded. The arithmetic unit 401 also generates a first control signal for the first motor 103 , Preferably, the arithmetic unit generates 401 in addition, a second control signal for the second motor 106 , The generated control signal is adapted to the change in dependence on the determined target yaw rate and the detected actual yaw rate. In a preferred embodiment of the invention, a first control signal for the first motor 103 and a second control signal for the second motor 106 each adapted to the same amount, but with different signs, so that by the inventive method for tracking stabilization of the wheelchair 100 not accelerated or decelerated.

In 5 is a diagram with a motor torque curve and a target yaw rate curve shown. At time t ₀ , the wheelchair user engages in the first power transmission device of the first drive wheel with a first force and in the second power transmission device of the second drive wheel with a second force, whereby the wheelchair is manually driven. In addition, for example, the typical power assist of the wheelchair is provided by a first motor torque of the first motor connected to the first drive wheel and a second motor torque of the second motor connected to the second drive wheel. The first engine torque and the second engine torque may be proportional or independent to the detected first force of the wheelchair user. In the 5 only the engine torque curve M _{1 of} a first engine is simplified 103 shown.

The period during which the wheelchair user exerts at least one force on the first power transmission device and / or the second power transmission device becomes engagement phase 501 called. The intervention phase 500 can be done for example by an acceleration sensor, which detects the acceleration of the wheelchair in the forward direction and / or backward direction. The intervention phase 501 begins with the time t ₀ and ends with the time t ₁ .

As soon as the wheelchair user grasps with his hands or no longer exerts any force on at least one power transmission device, the wheelchair unrolls. This period of time is considered a coasting phase 502 designated. The coasting phase 502 begins at time t ₁ and generally continues until the wheelchair comes to a halt or the wheelchair user again applies force to at least one power transmission device. For a power assisted wheelchair can be in the coasting phase 502 a time-decreasing engine torque M from the engine 103 be generated. This creates for a third person the impression of a manual wheelchair rather than an electric wheelchair, which has psychological advantages for the wheelchair user. The change 240 the motor torque or the motor torques of the first motor and / or the second motor for tracking stabilization can both in the engagement phase 501 as well as in the coasting phase 502 be carried out, the change 240 preferred only in the coasting phase 502 he follows.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0790049 A2 [0002]
• US 2002/0011361 A1 [0003]

Claims (17)

Method for the wheel stabilization of a wheelchair ( 100 ) comprising at least one power transmission device ( 102 . 105 ) to initiate a manual force of the wheelchair user ( 150 ) and at least one engine ( 103 . 106 ), which is a motor torque for power-assisted drive at least one drive wheel ( 101 . 104 ) of the wheelchair ( 100 ), wherein the method for tracking stabilization comprises the following steps: 210 ) of a current actual yaw rate (Ψ) about the vertical axis ( 120 ) of the wheelchair ( 100 ), and • Determination ( 220 ) a desired yaw rate (Ψ. _S ), and • calculation ( 230 ) a control difference (ΔΨ.) between the determined target yaw rate (Ψ. _S ) and the detected actual yaw rate (Ψ.), and • adaptation ( 240 ) of the engine torque as a function of the calculated control difference (ΔΨ.). Method according to claim 1, characterized in that the adaptation ( 240 ) of the engine torque takes place only in a coasting phase of the wheelchair. Method according to one of claims 1 or 2, characterized in that in an intervention phase of the wheelchair user the determination ( 220 ) of the desired yaw rate (Ψ. _S ) takes place. Method according to one of the preceding claims, characterized in that in a coasting phase of the wheelchair a change ( 221 ) of the desired yaw rate (Ψ. _S ) as a function of time. Method according to one of the preceding claims, characterized in that a detection ( 211 ) a current speed (v) of the wheelchair ( 100 ), whereby the determination ( 220 ) and / or the change of the desired yaw rate (Ψ, _S ) additionally takes place as a function of the detected speed (v). Method according to one of the preceding claims, characterized in that a calculation ( 212 ) of a current yaw angle (Ψ), a current roll angle (Φ) and / or a current pitch angle (Θ) of the wheelchair ( 100 ), the adaptation ( 240 ) of the at least one engine torque (M) additionally takes place as a function of the calculated yaw angle (Ψ), the calculated roll angle (Φ) and / or the calculated pitch angle (Θ). Method according to one of the preceding claims, characterized in that the determination ( 220 ) of the desired yaw rate (Ψ _S ) in the intervention phase of the wheelchair user and / or the coasting phase of the wheelchair in dependence on a detection ( 217 ) a lateral weight transfer of the wheelchair user takes place. Method according to one of the preceding claims, characterized in that the determination ( 220 ) of the desired yaw rate (Ψ. _S ) as a function of a detection ( 215 ) of a first force and / or acquisition ( 216 ) of a second force is performed. Control device which is set up to carry out a method according to one of Claims 1 to 8, characterized in that the control device ( 108 ) at least one arithmetic unit ( 401 ), wherein the arithmetic unit ( 401 ) at least • a current actual yaw rate (Ψ) about the vertical axis ( 120 ) of the wheelchair ( 100 ) Is detected, and • a target yaw rate (Ψ. _S) is determined, and • produces a control signal for a motor, wherein the control signal (in dependence on the detected actual yaw rate (Ψ.) And the determined target yaw rate Ψ. _S) adapted to change a motor torque (M) generated by the motor. Control unit according to claim 10, characterized in that the arithmetic unit ( 401 ) a first force of the wheelchair user ( 150 ) to a first power transmission device ( 102 ) and / or a second force of the wheelchair user ( 150 ) to a second power transmission device ( 104 ), wherein the target yaw rate (Ψ. _S ) is determined as a function of the detected first force and / or the second force. Control unit according to one of claims 9 or 10, characterized in that the arithmetic unit ( 401 ) a first force of the wheelchair user ( 150 ) to a first power transmission device ( 102 ) and / or a second force of the wheelchair user ( 150 ) to a second power transmission device ( 104 ), wherein the generated control signal is adjusted as a function of time, if no first and / or second force of the wheelchair user ( 150 ) is detected. Control device according to one of Claims 9 to 11, characterized in that the arithmetic unit ( 401 ) a current speed (v) of the wheelchair ( 100 ), wherein the control signal is adjusted in dependence on the detected speed (v). Control unit according to one of Claims 9 to 12, characterized in that the arithmetic unit ( 401 ) calculates a current yaw angle (Ψ), a current roll angle (Φ) and / or a current pitch angle (Θ), the control signal being dependent on the calculated yaw angle (Ψ), the calculated roll angle (Φ) and / or the calculated pitch angle ( Θ) is adjusted. Wheelchair, characterized in that the wheelchair ( 100 ) at least the following components • a first drive wheel ( 101 ) and / or a second drive wheel ( 104 ), each by means of a manual power transmission device ( 102 . 105 ), and • a motor ( 103 . 106 ) to the power assisted drive of the first drive wheel ( 101 ) and / or the second drive wheel ( 104 ), and • a control unit ( 108 ), according to one of claims 9 to 13, for driving the at least one motor ( 103 . 106 ), and • a yaw rate sensor ( 107 ). Wheelchair according to claim 14, characterized in that the wheelchair ( 100 ) comprises at least one force sensor, wherein the force sensor is adapted to the force exerted on a power transmission device force of the wheelchair user ( 150 ) capture. Wheelchair according to claim 14 or 15, characterized in that the wheelchair ( 100 ) a speed sensor ( 109 ), in particular a reed sensor, a GPS sensor and / or an acceleration sensor. Wheelchair according to one of claims 14 to 16, characterized in that the wheelchair is a sensor ( 110 ) for detecting a rate of rotation and / or acceleration in at least one further spatial direction, in particular a gyroscope.

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