Step ascending and descending device

Abstract

A step climbing device is provided with: a traveling unit (3) that includes three traveling wheels (31) that are capable of traveling on a floor surface by being imparted with autorotation, are disposed at equal angles around a rotating shaft, and are capable of revolving around the rotating shaft; a device frame (2) provided with at least the pair of travel units (3) on the left and right sides; a travel drive source (8) that rotationally drives the travel wheels (31); a vertical drive source (9) that drives the travel unit (3) to revolve; and a travel control unit (7) that controls the operation of the travel drive source (8) and the up-and-down drive source (9), the step up-and-down device up and down steps while revolving the travel unit (3), and the travel control unit (7) controls the operation of the travel drive source (8) and the up-and-down drive source (9) when driving the travel unit (3) to revolve. The traveling wheels (31) are driven to rotate in the direction opposite to the revolution direction at the same rotation angle as the revolution angle of the traveling unit (3).

Description

Technical Field

[0001] The present invention relates to a stair climbing and descending device, which can stably travel and move on a flat ground while carrying passengers, goods and the like, and can easily and safely climb and descend stairs and the like. Background Art

[0002] Electric wheelchairs are important welfare tools for the elderly and disabled to live independently without relying on assistants, and their use has become significant in a rapidly aging society. On the other hand, although ordinary electric wheelchairs can walk over small steps such as bumps on the road, they cannot go up and down large steps such as stairs, and there is a problem of obstacles in using them in buildings where it is difficult to install elevators. In addition, for the same reason, there is also a problem of obstacles when the elderly and disabled move heavy goods upstairs or downstairs.

[0003] Conventionally, as a method for solving such a problem, there have been proposed stair climbing and descending devices as disclosed in Patent Documents 1 and 2, which enable a person or a cargo to climb up and down stairs while the person is riding the staircase.

[0004] In the stair climbing device disclosed in the above document, a travel unit having three radially arranged travel wheels is provided on the left and right sides of the device frame. The three travel wheels rotate on their own and travel on the floor surface, and can revolve around the rotation axis of the travel unit, so that by appropriately driving the travel unit to rotate around the rotation axis, any of the three travel wheels can be brought into contact with the floor surface.

[0005] In the stair climbing device of Patent Document 1 or Patent Document 2 constructed in this way, on a flat road surface, two of the three running wheels included in the running unit are brought into contact with the road surface, and these running wheels are driven to rotate, thereby stably running on the road surface. In addition, when climbing stairs such as stairs, when any running wheel hits the riser of the step, the running unit is driven to rotate and the running wheel is made to revolve around the rotation axis of the running unit, and the running wheel that is not in contact with the road surface is brought into contact with the tread of the step, and the running unit is further driven to rotate, thereby lifting the device frame onto the step.

[0006] On the other hand, when going down stairs, the travel unit is driven to rotate when one of the travel wheels detaches from the road surface and reaches the tread below the riser, so that the travel wheel not in contact with the road surface contacts the tread under the step, thereby enabling the device frame to be lowered under the step.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2012-85854

[0010] Patent Document 2: Japanese Utility Model Registration No. 3234497 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in these conventional stair climbing and descending devices, when the travel unit is driven to cause the travel wheel to revolve, the travel wheel rotates relative to the road surface and the tread of the stairs even when the rotational drive of the travel wheel is stopped, so there is a problem that the posture of the device frame becomes unstable when climbing and descending stairs. In particular, when descending stairs, the travel wheel sometimes separates from the tread and falls to the tread below the riser due to the rotational drive of the travel unit, making it difficult to safely descend the stairs while passengers and cargo are loaded on the device frame.

[0013] Solutions to Solve Problems

[0014] The present invention has been completed in view of such a problem, and its purpose is to provide a stair climbing and descending device that can stably ascend and descend stairs such as stairs while carrying passengers and cargo using a travel unit having three travel wheels arranged radially.

[0015] That is, the stair climbing and descending device of the present invention comprises: a travel unit including three travel wheels, the travel wheels being able to be given self-rotation to travel on the floor surface, and the three travel wheels being arranged around the rotation axis at equal angles and being able to revolve around the rotation axis;

[0016] A device frame, which is provided with at least a pair of the travel units on the left and right sides;

[0017] A travel driving source, which drives the travel wheels to rotate;

[0018] A vertical driving source, which drives the travel unit to revolve; and

[0019] a travel control unit that controls the movement of the travel drive source and the up-and-down drive source,

[0020] The step up and down device moves up and down the steps while causing the travel unit to revolve.

[0021] The step up and down device is characterized in that:

[0022] The travel control unit drives the travel wheel to rotate in a direction opposite to the revolution direction at a rotation angle that is the same as the revolution angle of the travel unit when driving the travel unit to revolve.

[0023] Effects of the Invention

[0024] According to the present invention, regarding the driving control of the travel unit and the three travel wheels included in the travel unit when going up and down stairs, when the travel control unit drives the travel unit to revolve, the travel wheels are driven to rotate in the direction opposite to the revolving direction at the same rotation angle as the revolving angle of the travel unit, so that the travel unit can be driven to revolve in a state where the travel wheels stay on the tread. Therefore, in the present invention, the travel wheels will not accidentally rotate relative to the road surface or the tread of the stairs, so that the traveler can stably go up and down stairs such as stairs while carrying passengers and cargo. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram showing an example of an embodiment of an electric wheelchair to which the stair climbing and descending device of the present invention is applied.

[0026] Figure 2 1 is a schematic diagram showing a state where the electric wheelchair according to the embodiment goes up and down stairs.

[0027] Figure 3 It is a perspective view showing an example of the running wheel according to the embodiment.

[0028] Figure 4 This is a block diagram showing a control system of the electric wheelchair according to the embodiment.

[0029] Figure 5 This is a schematic diagram of the operation of the travel unit and the travel wheels included in the travel unit when the electric wheelchair according to the embodiment goes down from the road surface to the first step of the stairs.

[0030] Figure 6 1 is a schematic diagram showing the operation of a travel unit and travel wheels included in the travel unit when the electric wheelchair according to the embodiment goes down from the first step to the second step of the stairs.

[0031] Figure 7 This is a schematic diagram showing the operation of a travel unit and travel wheels included in the travel unit when the electric wheelchair according to the embodiment climbs up the first step of stairs from a road surface. DETAILED DESCRIPTION

[0032] Hereinafter, the stair ascending and descending device of the present invention will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 1 is a schematic diagram showing an embodiment of the stair climbing device according to the present invention applied to an electric wheelchair. The electric wheelchair 1 moves forward, backward, left, and right by the operation of a passenger M sitting on the seat surface, and is configured to be able to move not only on flat ground but also up and down stairs such as stairs when the passenger M is seated.

[0034] The electric wheelchair 1 includes an apparatus frame 2, four travel units 3 provided on the left, right, front and back sides of the apparatus frame 2, and a seat frame 4 provided so as to be tiltable relative to the apparatus frame 2 and provided with a seat surface 40 for a passenger M to sit on. The seat frame 4 is rotatably coupled to the apparatus frame 2 via a support shaft 41, and is connected to the apparatus frame 2 by an actuator (not shown), so that the connection angle of the seat frame 4 relative to the apparatus frame 2 can be freely adjusted by the extension and contraction of the actuator. In addition, the apparatus frame 2 is provided with an inclination sensor (not shown) for detecting the inclination of the apparatus frame 2 relative to the horizontal.

[0035] Therefore, if Figure 2 As shown in the sub-figures a and b of , when the device frame 2 is tilted relative to the horizontal during the process of going up or down a ramp or stairs, the tilt angle can be grasped according to the signal of the tilt sensor, and the extension and contraction of the actuator can be controlled based on the signal, thereby freely changing the connection angle of the seat frame 4 relative to the device frame 2. Therefore, even when the passenger M goes up or down a ramp or stairs while sitting on the seat surface 40, the seat surface 40 can always be kept horizontal regardless of how the device frame 2 tilts, thereby ensuring the safety of the passenger M.

[0036] Next, the four traveling units 3 provided on the device frame 2 will be described.

[0037] Each travel unit 3 is formed by arranging three travel wheels 31 radially around a drive shaft 30, and the three travel wheels 31 can be made to revolve around the drive shaft 30. The three travel wheels 31 are connected to a motor as a travel drive source via a reduction gear, and are driven to rotate in the same direction at the same speed. In addition, a motor as an up and down drive source is connected to the drive shaft 30 of the travel unit 3, and by driving the travel unit 3 to revolve, one or two of the three travel wheels 31 can be selectively brought into contact with a road surface such as the ground or a floor surface. In addition, the drive shaft 30 of each travel unit 3 can be arbitrarily switched to drive revolving, stopping, and free rotation.

[0038] The electric wheelchair 1 is intended to be able to change the travel direction freely according to the driving operation of the rider, and therefore, a steering mechanism is required for at least two travel units 3 provided at the front side of the device frame 2 or two travel units 3 provided at the rear side as the travel units 3. On the other hand, the steering mechanism can be omitted by configuring all three travel wheels 3 provided by the travel units 3 as so-called omnidirectional wheels. The omnidirectional wheels can be used, for example, Figure 3The Mecanum wheel 10 shown. The Mecanum wheel 10 has a plurality of auxiliary rollers 10b having a rotation axis inclined 45 degrees relative to the rotation axis of the running wheel body 10a disposed on the outer peripheral surface of the rotating running wheel body 10a. When the running wheel body 10a is driven to rotate, the Mecanum wheel 10 itself intends to move in a direction inclined 45 degrees relative to the rotation direction of the running wheel body 10a.

[0039] The Mecanum wheels 10 are arranged on each travel unit 3 in such a way that the rotation axis of the auxiliary roller 10b is oriented toward the center of the device frame 2. Therefore, for example, by using the travel unit 3 located on the front side of the device frame 2 and the travel unit 3 located on the rear side to make the rotation direction of the Mecanum wheel 10 different, the device frame can be moved laterally to the left and right. In addition, by using the travel unit 3 located on the right side of the device frame 2 and the travel unit 3 located on the left side to make the rotation direction of the Mecanum wheel 10 different, the device frame can be turned on the spot. By setting all three travel wheels 31 of the travel unit as Mecanum wheels 10 and only controlling the rotation direction of each travel wheel, the device frame can be freely moved forward, backward, left, right, in an inclined direction, and in a rotating motion. It should be noted that the motion control of the robot trolley using the Mecanum wheels 10 is well known, so its detailed description is omitted here.

[0040] Figure 4 1 is a block diagram showing a control system related to the travel of the electric wheelchair 1. The device frame 2 is provided with a camera 5 for photographing the front of the electric wheelchair 1, and the seat frame 4 is provided with an operation panel 6 for the passenger M to input the travel direction. The signals sent from the camera 5 and the operation panel 6 are input to the travel control unit 7. In addition, the drive shaft 30 of the travel unit 3 is provided with a revolution encoder 32 for detecting the rotation amount of the drive shaft 30, and the rotation shaft of the travel wheel 31 is provided with a travel amount encoder 33 for detecting the rotation amount of the travel wheel 31. The travel control unit 7 is realized by a computer including an MPU, executes a predetermined travel program pre-stored in a memory, processes the signals input from the camera 5, the operation panel 6, the revolution encoder 32, and the travel amount encoder 33, and sends a drive signal to the travel drive source 8 and the up-down drive source 9. Thus, the revolution, stop, and free rotation of the travel unit 3 are controlled, and the rotation drive and stop of the travel wheel 31 included in the travel unit 3 are controlled.

[0041] In addition, the travel control unit 7 can detect the starting position of the stairs, the height of the riser of each step on the stairs, the length of the tread, the edge of the steps of the stairs, and other step information by analyzing the image captured by the camera 5. At this time, by irradiating the laser toward the front of the electric wheelchair 1 and measuring the distance from the laser reflected in the image captured by the camera 5 to the object, more accurate information such as the length can be detected. In addition, the travel control unit 7 can detect the edge of the steps of the stairs and determine whether the electric wheelchair 1 is facing the steps. On the other hand, the travel control unit 7 detects the information of the travel distance of the travel wheel 31 relative to the road surface based on the detection signal of the travel amount encoder 33. Thereby, the travel control unit 7 grasps the position of each travel wheel 31 relative to the steps of the stairs. Hereinafter, the function that can detect the above information will be referred to as the information detection unit.

[0042] It should be noted that the method for detecting the starting position of the stairs, the height of the risers of each step of the stairs, and the length of the treads is not limited to the analysis of the image captured by the aforementioned camera 5, and various sensors such as laser distance meters, optical or contact sensors can also be used.

[0043] Figure 5 as well as Figure 6 1 is a schematic diagram showing a state of the travel units 3A and 3B and the travel wheels 31 included therein when the electric wheelchair 1 according to the present embodiment goes down stairs.

[0044] Figure 5 The device frame 2 is shown in a state before it descends from a flat road surface to the first step of the stairs. As shown in sub-figure a, in each of the travel units 3A and 3B disposed in front and behind the device frame 2, the two travel wheels 31 are in contact with the road surface, and by driving each travel wheel 31 to rotate, the electric wheelchair 1 moves forward on the road surface in the direction of arrow A in the figure. At this time, the travel control unit 7 detects the edge of the step using the information detection unit to control the travel of the electric wheelchair 1 so that the electric wheelchair 1 faces the edge. In addition, in this state, although the drive shaft 30 of the travel unit 3 is in a free-rotating state, the two travel wheels 31a and 31b included in each travel unit 3 are in contact with the road surface, so that the travel unit 3 does not revolve and is in a stable state. When the leading travel wheel 31a of the front travel unit 3A is separated from the road surface and approaches the first step below the stairs, since the drive shaft 30 of the travel unit 31A is set to rotate freely, the travel wheel 31a contacts the riser U1 of the step and descends to the first step tread F1 (sub-figure b).

[0045] In this state, when the travel control unit 7 determines that the travel wheel 31a of the front travel unit 3A is in contact with the tread F1, the information detection unit detects the step information. Then, the numerical value of the length of the tread F1 as the step information is compared with a pre-stored threshold. The threshold is determined based on the arrangement interval between the travel wheels 31a and the travel wheels 31c and the size of the travel wheels, and is a numerical value of the length that can be carried by both the travel wheels 31a and the travel wheels 31c on the tread. Based on the result of the comparison, the travel control unit 7 selects and executes either a travel process for causing the travel unit to travel on the tread F1 or a revolution drive process for causing the travel unit to move to different steps.

[0046] exist Figure 5 In the sub-figure c of FIG. 1 , the travel control unit 7 selects and executes the revolution drive process. The revolution drive process temporarily stops the rotation drive of the travel wheel 31, maintains the state in which the travel wheel 31a of the front travel unit 3A is in contact with the first step tread F1, and causes the front travel unit 3A to revolve in the direction of arrow R. As a result, the travel wheel 31b of the front travel unit 3A in contact with the road surface on the stairs leaves the road surface, and the travel wheel 31c descends toward the first step tread F1, and at the same time, the drive shaft 30 of the front travel unit 3A moves with the travel wheel 31a as the rotation center, so that the device frame 2 moves in the direction of arrow A.

[0047] In addition, when the travel unit 3A is revolved, the travel control unit 7 drives the travel wheels 31 included in the travel unit 3A to rotate in the direction opposite to the revolving direction by the same angle as the revolving angle of the travel unit 3A. If the travel wheels 31 included in the travel unit 3A are kept in a stopped state in advance during the revolving of the travel unit 3A, the travel wheels 31a will roll on the tread F1 according to the revolving of the travel unit 3A, and there is a risk that the entire travel unit 3A will unintentionally detach from the tread F1 and roll down to the next level. In order to avoid this risk, such rotation control of the travel wheels 31 is required. When the travel wheels 31a are driven to rotate in the direction opposite to the revolving direction during the revolving of the travel unit 3A, the travel wheels 31a stay on the first level tread F1, thereby preventing the travel unit 3A from detaching from the tread F1 and rolling down to the next level. As a result, the posture of the device frame 2 can be stabilized even if the travel unit 3A revolves. It should be noted that by setting the travel wheel 31a to be in contact with the riser U1 in addition to the first step tread F1, the posture of the device frame 2 can be further stabilized. In addition, when the travel unit 3A is revolved, the travel wheel 31 included in the rear travel unit 3B becomes a freely rotating state, and rolls on the road surface in accordance with the movement of the device frame 2 in the direction of arrow A.

[0048] Figure 6FIG. a shows the state after the revolution drive process of the travel unit is executed. For the travel control unit 7, when the travel wheel 31c contacts the first-level tread F1 with the revolution drive process of the front travel unit 3A, the travel control unit 7 changes the setting of the travel unit 3A from the revolution in the direction of the arrow R to free rotation, stops the reverse rotation of the travel wheels 31 included in the travel unit 3A, and drives these travel wheels 31 to rotate in the positive direction. As a result, as shown in FIG. b, the travel wheel 3c of the front travel unit contacts the second-level riser U2 and descends to the second-level tread F2.

[0049] Then, if Figure 6 As shown in FIG. c, when the travel control unit 7 determines that the travel wheel 31c of the front travel unit 3A has come into contact with the tread F2, the information detection unit detects the step information again and compares the value of the length of the tread F2 with a pre-stored threshold. Figure 6 In the sub-figure c of , the travel control unit 7 selects and executes the revolution drive processing. Therefore, the travel control unit 7 temporarily stops the rotation drive of the travel wheel 31, maintains the state in which the travel wheel 31c of the front travel unit 3A is in contact with the second-level tread F2, and causes the front travel unit 3A to revolve in the direction of arrow R. As a result, the travel wheel 31a of the front travel unit 3A in contact with the first-level tread F1 leaves the tread F1, and the travel wheel 31b descends toward the second-level tread F2, and at the same time, the drive shaft 30 of the front travel unit 3A moves with the travel wheel 31c as the rotation center, so that the device frame 2 moves in the direction of arrow A. The rotation control of the travel wheel 3c during the revolution of the travel unit is the same as Figure 5 The same as the case of the sub-figure c of FIG. 1, thereby making it possible to make the travel unit 3A revolve while making the travel wheel 31c of the front travel unit stay on the second-level tread F2, thereby stabilizing the posture of the device frame 2 going down the stairs. It should be noted that in the case of a tread shorter than the tread F1 shown in this embodiment, there is a case where the travel control unit 7 performs the revolving drive process. Figure 5 From the state of the sub-figure c, the running wheel 31c does not contact the tread F1 but contacts the next level tread F2 of the tread F1. Figure 6 In the state of the sub-figure a, the travel control unit 7 does not stop the revolution of the travel unit but continues to execute the revolution drive process.

[0050] On the other hand, the travel control unit 7 may also Figure 5 The driving process is performed in the state of sub-figure b. The driving process is performed based on the step information detected by the information detection unit, that is, the length of the tread F1 and the height of the riser U2 below the tread F1. The driving process is to make the driving unit move from Figure 5The process is performed before the state of the sub-graph b of FIG. 1 is lowered to the next stage of the tread F2, and the travel unit is slightly advanced in the state where the front and rear travel wheels in the same travel unit are in contact with the ground contact surfaces of different heights. This travel process is effective in the following cases: Figure 5 When the travel control unit 7 performs the revolution drive process in the state of the sub-figure b, the travel wheel 31c does not contact the tread F1, and does not contact the tread F2 of the next level of the tread F1. Assuming that the revolution drive process is performed in this state, the travel wheel 31c contacts the kick surface U2 in a state of floating from the tread F2, and the electric wheelchair 1 becomes unstable. Figure 5 The travel unit is slightly advanced in the state of FIG. b and then the revolution drive process is performed, so that the travel wheel 31c can contact the next tread F2 with the revolution of the travel unit. The distance the travel unit advances is determined by the length of the tread F1 and the height of the riser U2 below the tread F1.

[0051] When the preceding travel wheels 31a of the rear travel unit 3B reach the stairs, the same drive control as that of the front travel unit 3A is applied to the travel unit 3B.

[0052] Figure 7 1 is a schematic diagram showing the state of the travel units 3A and 3B and the travel wheels 311 included therein when the electric wheelchair 1 according to the present embodiment goes up stairs.

[0053] Figure 7 The device frame 2 is shown climbing up the first step of the stairs from a flat road surface. As shown in sub-figure a, when the device frame 2 moves in the direction of arrow A and the leading travel wheel 31a of the front travel unit 3A hits the upper first step riser U1 of the stairs, the travel control unit 7 temporarily stops the rotation drive of the travel wheel 31, maintains the state in which the travel wheel 31a of the front travel unit 3A is in contact with the first step riser U1, and causes the front travel unit 3A to revolve in the direction of arrow R. As a result, the travel wheel 31b of the front travel unit 3A in contact with the road surface under the stairs leaves the road surface, and the travel wheel 31c descends toward the first step tread F1, and at the same time, the drive shaft 30 of the front travel unit 3A moves with the travel wheel 31a as the rotation center, so that the device frame 2 moves in the direction of arrow A. It should be noted that, although the travel wheel 31a of the travel unit 3A is maintained in contact with the first riser U1, the travel wheel 31a is not necessarily in contact with the riser U1, and a gap may be formed between the travel wheel 31a and the riser U1 as long as the travel wheel 31c can be lowered toward the first tread F1. Whether the travel wheel 31c can be lowered toward the first tread F1 is determined by the travel control unit 7 based on the image captured by the camera 5.

[0054] In addition, when the travel unit 3A is revolved, the travel control unit 7 drives the travel wheels 31 included in the travel unit 3A to rotate in the direction opposite to the revolving direction R by the same angle as the revolving angle of the travel unit 3A. If the travel wheels 31 included in the travel unit 3A are kept in a stopped state in advance during the revolving of the travel unit 3A, the travel wheels 31a will try to rise on the riser U1 according to the revolving of the travel unit 3A, so there is a risk that the entire travel unit 3A will shake up and down along the riser U1 unintentionally and become unstable. In order to avoid this risk, such rotation control of the travel wheels 31 is required. When the travel wheels 31a are driven to rotate in the direction opposite to the revolving direction during the revolving of the travel unit 3A, the travel wheels 31a stay on the road surface, so that the posture of the device frame 2 can be stabilized even if the travel unit 3A revolves. It should be noted that when the travel unit 3A is revolved, the travel wheels 31 included in the rear travel unit 3B are in a freely rotatable state, and roll on the road surface in accordance with the movement of the device frame 2 in the direction of arrow A.

[0055] When the travel control unit 7 determines that the travel wheel 31c has come into contact with the first-level tread F1 due to the revolution of the front travel unit 3A, the travel control unit 7 detects the step information through the information detection unit. The travel control unit 7 compares the numerical value of the length of the tread F1 as the step information with a pre-stored threshold. The threshold is determined based on the configuration interval between the travel wheels 31a and the travel wheels 31c and the size of the travel wheels, and is a numerical value of the length that can be carried by both the travel wheels 31a and the travel wheels 31c on the tread. Based on the result of the comparison, the travel control unit 7 selects and executes either a travel process for moving the travel unit forward or a revolution drive process for moving the travel unit to different steps. Figure 7 As shown in the sub-figure b of FIG. 1 , for the travel process, when the travel wheel 31c contacts the first-level tread F1 with the revolution of the front travel unit 3A, the travel control unit 7 changes the setting of the travel unit 3A from the revolution in the direction of the arrow R to free rotation, stops the reverse rotation of the travel wheels 31 included in the travel unit 3A, and drives the travel wheels 31 to rotate in the positive direction. As a result, the travel wheel 3c of the front travel unit 3A moves toward the riser U2 on the first-level tread F1, and the travel unit 3A is lifted onto the first-level tread F1 as a whole.

[0056] When the travel wheel 3c moves on the first step tread F1 and hits the second step riser U2, the travel control unit 7 temporarily stops the rotation drive of the travel wheel 31, maintains the state where the travel wheel 31c of the front travel unit 3A stays on the first step tread F1, and makes the front travel unit 3A revolve in the direction of arrow R. As a result, the travel wheel 31a of the front travel unit 3A leaves the road surface, and the travel wheel 31b descends toward the second step tread F2. At the same time, the drive shaft 30 of the front travel unit 3A moves with the travel wheel 31c as the rotation center, so that the device frame 2 moves in the direction of arrow A. The rotation control of the travel wheel 3c during the revolution of the travel unit is the same as Figure 7 The same as the case of the sub-figure a, thereby making it possible to make the travel unit 3A revolve while keeping the travel wheel 31c of the front travel unit on the first step F1, so that the posture of the device frame 2 climbing the stairs can be stabilized.

[0057] On the other hand, Figure 7 In the state of the sub-figure (b) of FIG. 1 , the travel control unit 7 sometimes also performs the revolution drive processing according to the result of comparing the numerical value of the length of the tread F1 as the step information with the pre-stored threshold value. In the case of the revolution drive processing, the revolution of the travel unit is performed after the revolution of the travel unit when the preceding travel wheel 31a of the front travel unit 3A hits the riser U1 of the upper first step of the stairs. At this time, the travel wheel 31 is driven to rotate in the direction opposite to the revolution direction R by the same angle as the travel unit 3A. As a result, the travel wheel 31b passes through the tread F1 in a circular arc while the travel wheel 31c contacts and stays on the tread F1, and descends to the tread of the upper level of the tread F1. The revolution drive processing is more effective when the result of comparing the numerical value of the length of the tread F1 as the step information with the threshold value is that the numerical value of the length of the tread F1 is less than the threshold value.

[0058] When the leading travel wheels 31a of the rear travel unit 3B reach the first riser U1, the same drive control as that of the front travel unit 3A is applied to the travel unit 3B, whereby the device frame 2 can stably climb the stairs step by step.

[0059] As described above, according to the electric wheelchair 1 of this embodiment, when the travel unit 3 having three travel wheels 31 arranged radially and capable of driving the travel wheels 31 to revolve is used to go up and down stairs, when the travel control unit 7 controls the travel unit 3 to revolve, the travel wheel is driven to rotate in the direction opposite to the revolving direction at the same rotation angle as the revolving drive of the travel unit 3. As a result, the travel unit 3 can be driven to revolve in a state where one of the travel wheels in contact with the tread is kept on the tread. Therefore, there is no concern that the travel wheel will not be driven inadvertently during the revolving of the travel unit and the travel wheel will fall on the tread under the step, so that the travel unit can be revolved stably and the posture of the device frame having the travel unit can be stabilized. Therefore, the electric wheelchair 11 can go up and down stairs, etc., in a stable posture in the state where there is a passenger. In addition, if the revolving drive of the travel unit 3 is performed under the condition that one of the travel wheels included in the travel unit 3 is in continuous contact with both the riser and the tread of the step, it is possible to go up and down stairs, etc., in a more stable posture.

[0060] Furthermore, since the travel control unit 7 can control the electric wheelchair 1 so that the electric wheelchair 1 faces the edge of the step, not only can the stability of the straight staircase be ensured, but also, even in the case of a curved staircase, the situation that one of the left and right travel units provided on the electric wheelchair 1 falls on the tread unintentionally can be prevented. In this case, the direction of the electric wheelchair 1 can be easily changed by using the Mecanum wheels, so that the electric wheelchair 1 can easily face the edge of the step. In addition, by using the Mecanum wheels as the travel wheels 31 included in each travel unit 3 provided on the front, back, left, and right sides of the device frame 2, the Mecanum wheel rotation direction of each travel unit is controlled even in the process of going up and down the stairs, so that the device frame can be moved in the left and right lateral direction, so that the stairs can be avoided while going up and down the stairs.

[0061] It should be noted that, in this embodiment, an example of applying the step-up and down-down device of the present invention to the electric wheelchair 1 is specifically described, but the present invention can also be applied to uses other than wheelchairs such as transporting goods by replacing the seat frame 4 with a platform frame.

Claims

1. A stair up and down device, The step up and down device comprises: A travel unit (3), comprising three travel wheels (31), wherein the travel wheels (31) can be given self-rotation to travel on a floor surface, and the three travel wheels (31) are arranged around a rotating axis at equal angles and can revolve around the rotating axis; A device frame (2) having at least one pair of the travel units (3) disposed on the left and right sides; A travel driving source (8) driving the travel wheel (31) to rotate; An up and down driving source (9) for driving the travel unit (3) to revolve; and A travel control unit (7) controls the operation of the travel drive source (8) and the up-and-down drive source (9). The step up and down device moves the steps up and down while causing the travel unit (3) to revolve. The step up and down device is characterized in that: When the travel unit (3) is driven to revolve, the travel control unit (7) drives the travel wheels (31) to rotate in a direction opposite to the revolving direction at a rotation angle that is the same as the revolving angle of the travel unit (3).

2. A stair up and down device, characterized in that: The travel unit (3) is driven to revolve under the condition that one of the travel wheels (31) included in the travel unit (3) is in continuous contact with both the riser and the tread of the step.

3. The stair up and down device according to claim 1, characterized in that: The three running wheels (31) included in the running unit (3) are Mecanum wheels serving as omnidirectional wheels.

4. The stair up and down device according to claim 1 or 3, characterized in that: The travel control unit (7) moves the step up and down in a state where the device frame (2) faces the edge of the step.

Images