JP2017003383A - Step detection device and step getting-over device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a step detection device for detecting a step using contact-type detection means and a step getting-over device for getting over a step which mounts the step detection device thereon.SOLUTION: An acceleration sensor 300 which is attached to a portion contacting a rotary axis of a drive wheel 101, and detects acceleration in two-axis directions forming a right angle in a plane which is vertical to the rotary axis of the drive wheel, is provided as a step detection device. When a step on a track and the drive wheel contact, a resistance direction angle is determined from the two-axis direction component of resistance acceleration obtained from the acceleration sensor, then a height h of the step is estimated based on the resistance direction angle. In a step getting-over device, the step detection device is provided, and drive wheels 101, 103 are arranged on a front side of a front wheel 201 and a rear side of a rear wheel 202 of a bogie, and actuators 102, 104 for changing a height of the drive wheels, are provided, and based on a value of the resistance direction angle θ, it is determined whether a step which the front side drive wheel contacts, is in a direction of rising to a travel direction of the bogie, or in a direction of lowering, then, the actuators are operated by the height of the step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a step detection device and a step climbing device that are used by being attached to a carriage for transporting heavy equipment when installing elevator equipment such as elevators and escalators at construction sites such as buildings and condominiums. It is about.

  In a conventional mobile robot or a transfer device having a step-over function, as a method of detecting a step, an image captured by a camera is processed, or a laser or ultrasonic wave is irradiated and reflected back. The level difference is detected by making full use of non-contact means and analysis processing technology, such as analyzing and recognizing a signal detected by a detector using laser or ultrasonic waves. And there exists what performed control of the arm which raises / lowers a wheel based on this detected level | step difference (for example, refer patent document 1).

JP 2005-28971 A

  It is necessary to carry the equipment in both outdoor and indoor environments. However, in the case of a step detection device using non-contact means such as the above-mentioned Patent Document 1, the difference in surface reflection on the conveyance path, or The detection signal fluctuates greatly depending on the difference in brightness depending on the weather and whether the surface is dry or wet, making it unsuitable as a means of sensing the level difference for trucks used at construction sites.

  The present invention provides a device for detecting a level difference by using a contact type detection means and a device for overcoming the level difference using the level difference detection device, which have been made to solve the problems of the prior art. For the purpose.

  In order to achieve the above object, a level difference detecting device according to the present invention is attached to a portion in contact with a rotation axis of a drive wheel, and a biaxial acceleration that forms a right angle in a plane perpendicular to the rotation axis of the drive wheel. When the driving wheel comes into contact with the acceleration sensor for detecting the road, the drag direction angle is obtained from the biaxial component of the drag acceleration obtained from the acceleration sensor, and the height of the step is calculated from the drag direction angle. And a control device for estimating the height.

  Further, the present invention is a step climbing device provided with the step detection device described above, wherein the drive wheel is disposed on the front side and the rear side of the front wheel and the rear wheel of the carriage, respectively, and includes an actuator that changes the height of the drive wheel. And the control device determines, from the value of the drag direction angle, whether the step with which the front drive wheel is in contact is an upward direction or a downward direction with respect to the traveling direction of the carriage. A step-over device for operating the actuator by the height of is provided.

  According to the present invention, the sensor that detects the acceleration in the biaxial direction is provided at a portion that is in contact with the rotation axis of the driving wheel, and the drag direction is detected from the detected biaxial component when the step on the traveling road and the driving wheel are in contact with each other. Since the step detection device is configured to estimate the height of the step by obtaining the angle, it is possible to recognize the step by a simple calculation with a simple contact method without being affected by environmental changes such as the construction site. In addition, it is possible to provide a step-over device in consideration of safety when transporting a heavy object based on the step.

It is a schematic side view which shows the relationship between the level | step difference climbing apparatus which mounts the level | step difference detection apparatus which concerns on this invention, and an up step and a down step. It is the schematic which showed the relationship between the drag direction on the basis of the gravitational direction at the time of level | step contact, and the acceleration sensor attached to the front-wheel axle in the level | step crossing apparatus of this invention carrying the level | step difference detection apparatus which concerns on this invention. It is a block diagram which shows the electrical control system of the level | step difference detection apparatus which concerns on this invention, and the level | step difference climbing apparatus which concerns on this invention incorporating this level | step difference detection apparatus. It is the schematic for demonstrating the climbing operation of the level | step difference in the up direction of the level | step climbing apparatus which mounts the level | step difference detection apparatus which concerns on this invention. It is the schematic for demonstrating the level | step difference operation | movement in the down direction of the level | step crossing apparatus based on this invention carrying the level | step difference detection apparatus based on this invention. It is a flowchart which shows the calculation process in the level | step difference detection apparatus which concerns on this invention shown in FIG. 3, and the level | step difference climbing apparatus which concerns on this invention incorporating this level | step difference detection apparatus. 7 is a flowchart showing an operation process when the step climbing apparatus according to the present invention shown in FIG. 3 gets over an upward step based on the calculation result of the flowchart of FIG. 6. 7 is a flowchart showing an operation process when the step climbing apparatus according to the present invention shown in FIG. 3 gets over a downward step based on the calculation result of the flowchart of FIG. 6. It is the figure which showed the relationship between the drag from the level | step difference which acts on a drive wheel at the time of level | step contact in this invention, a loading load, and level | step climbing force. FIG. 6 shows a relationship from 0 degree to 90 degrees in the direction angle θ of the drag generated at the time of step contact with respect to the ratio h / r of the step height h and the wheel radius r calculated by the step detecting device according to the present invention. FIG. The figure shows how many times the overcoming force is required with respect to the load applied to the driving wheel with respect to the ratio h / r between the step height h and the wheel radius r calculated by the step detecting device according to the present invention. FIG. It is the figure which showed the structure which connected the level | step climbing apparatus concerning this invention carrying the level | step difference detection apparatus concerning this invention to the separate trolley | bogie.

(Conveying route using cart)
As a travel route of the step-over device according to the present invention, a pavement roadway and a sidewalk, and an iron floor having a thickness of several to 20 mm laid for curing are assumed. In addition, the steps are assumed to be steps with edges that are close to right angles, such as the curb of the concrete block on the boundary of the sidewalk from the roadway and the warpage of the floorboard and the height difference between adjacent floorboards due to the unevenness of the ground. ing. The warp of the floorboard and usually the roadway and the sidewalk have an inclined surface, and the road surface is not necessarily limited to a horizontal surface.

  In addition, after loading equipment outdoors, the width becomes narrower and the bending becomes tighter as it approaches the building for construction, as it passes the road from the roadway to the sidewalk. Once inside, there is only a width for people to live, and the surrounding area is a narrow passage partitioned by walls. Outside, there is a large disparity in environmental changes between day and night and fine weather. Indoors, a stable lighting state cannot be obtained, and the brightness changes greatly over the entire length of the conveyance path.

Embodiment 1 FIG.
Hereinafter, a step detection device and a step climbing device according to Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  In FIG. 1 showing a step climbing apparatus equipped with a step detecting device according to the present invention, a carriage 200 is a generally known carriage, and two carriage caster front wheels 201 and two carriage caster rear wheels 202 are fixed. Has been. The step-over device according to the present invention is used by connecting and fixing the base 100 to the lower portion of the carriage 200. However, the present invention is not limited to this, and it goes without saying that the base may be built into the cart from the beginning.

  In the case of the structure in which the base 100 is connected to the carriage 200, it is easy to install and remove. Therefore, not only can the carriage suitable for the equipment be used, but also the equipment costs such as the power source and the drive motor can be reduced and transported by truck. Occupancy can be reduced.

  A front wheel lifting / lowering actuator 102 and a rear wheel lifting / lowering actuator 104 are attached to the base 100 of the step climbing apparatus. A front wheel 101 is attached to the front end portion of the front wheel lifting actuator 102, and a rear wheel 103 is attached to the front end portion of the rear wheel lifting actuator 104. Even when the caster front and rear wheels 201 and 202 of the carriage 200 are not used, even when a full load is applied to the front and rear lifting actuators, the cart 200 can move up and down independently of the front and rear.

  Since the carriage 200 is connected and fixed to the step climbing device, the carriage 200 can be moved up and down while maintaining the level by the vertical movement of the front wheel lifting actuator 102 and the rear wheel lifting actuator 104.

  The front wheel lifting / lowering actuator 102 and the rear wheel lifting / lowering actuator 104 incorporate a load sensor (not shown) and detect the load received by the front wheel 101 and the rear wheel 103 as driving wheels. A biaxial acceleration sensor 300 is fixed to the axle 105 of the front wheel 101 of the step climbing device. The biaxial acceleration sensor 300 axes the drag acceleration of the front wheel 101 generated when the front wheel 101 contacts the step in the biaxial direction. , Ax can be decomposed and measured. Since ax and az can be measured by disassembling in the biaxial direction, the angle θ of the drag acceleration with respect to the direction of gravitational acceleration can be obtained.

  As shown in FIG. 1A, the front wheel 101 can measure the drag A at the time of contact not only with the step forward in the traveling direction but also with the step backward in the traveling direction as shown in FIG. . As described later, the step height h can be obtained based on the drag components ax and az measured by the biaxial acceleration sensor 300.

FIG. 2 shows the relationship between the acceleration sensor 300 attached to the axle 105 of the front wheel 101 and the drag direction based on the direction of gravity in the step-over device of the present invention.
FIG. 2A shows the relationship between the step h and the two-axis acceleration sensor 300 fixed to the front wheel 101 of the step climbing device, the support portion of the front wheel lifting / lowering actuator 102, and the axle 105 of the front wheel 101.

  FIG. 2A shows a state in which the front wheel 101 having a radius r is in contact with the corner of the step h while the front wheel 101 of the step climbing apparatus is in contact with the surface in front of the step. In this case, the drag A received by the wheel 101 is generated in the direction toward the center of the axle 105 of the wheel 101 in a direction perpendicular to the tangent of the circle at the contact point with the step h. By measuring the drag acceleration A with the biaxial acceleration sensor 300 as the biaxial components ax and az, the drag direction angle θ based on the direction of gravity can be easily obtained as shown in FIG. .

  FIG. 2B shows a state in which the tilt of the biaxial acceleration sensor 300 is changed by the lifting operation of the front wheel lifting actuator 102 and the drag is changed from A to A1 (the angle is changed from θ to θ1). In any case, it is shown that the remaining step height h can be obtained from the current position of the front wheel 101 by using the gravitational acceleration g as a reference.

FIG. 3 shows an electrical control system of the step detection device according to the present invention and the step climbing device controlled by the calculation output of the step detection device.
In the figure, the control device 10 includes an arithmetic circuit 11 and a storage device 12 to form a level difference detection device. The front and rear wheels have a radius r given as a set value and a front wheel of the drag A detected by the acceleration sensor 300. The acceleration components ax and az and the load W detected by a load sensor (not shown) attached to the actuator 102 are input, and the direction A of the drag A and the step height h are overcome as will be described later. The force F is calculated.

  Θ, h, and F calculated by the control device 10 are sent to the front wheel drive circuit 20a and the rear wheel drive circuit 20b. The front wheel drive circuit 20 a gives a rotation amount to the front wheel drive motor 108 a and gives a lift amount to the front wheel lift actuator 102. The rear wheel drive circuit 20 b gives a rotation amount to the rear wheel drive motor 108 b and gives a lift amount to the rear wheel lift actuator 104.

4 (a) to 4 (f) show the operation process in the upward direction of the step climbing apparatus of the present invention as follows.
(A) The front wheel lifting / lowering actuator 102 is driven, and the front wheel 101 is raised by the step height h determined by the control device 10 through calculation.
(B) The rear wheel drive motor 108b is driven to move the rear wheel 103 forward.
(C) Both the front wheel lifting actuator 102 and the rear wheel lifting actuator 104 are simultaneously lowered at the same speed by the height h, and the carriage 200 is raised by the height h while being horizontal.
(D) The rear wheel drive motor 108b is driven to move the rear wheel 103 forward.
(E) The rear wheel lifting / lowering actuator 104 is driven to raise the rear wheel 103 by the step height h.
(F) The front wheel drive motor 108a is driven to move the front wheel 101 forward.

5 (a) to 5 (f) show the operation process in the downward direction of the step climbing apparatus of the present invention as follows.
(A) The rear wheel drive motor 108b is driven to move the rear wheel 103 forward.
(B) The front wheel lifting / lowering actuator 102 is driven, the front wheel 101 is lowered to the lower surface of the step, and the step height h is measured.
(C) The rear wheel drive motor 108b is driven to move the rear wheel 103 forward.
(D) Both the front wheel lifting / lowering actuator 102 and the rear wheel lifting / lowering actuator 104 are simultaneously raised at the same speed by the height h, and the carriage 200 is lowered by the height h while being horizontal.
(E) The front wheel drive motor 108a is driven to move the front wheel 101 forward.
(F) The rear wheel lifting / lowering actuator 104 is driven to lower the rear wheel 103 by the step height h.

The operation of FIGS. 4 and 5 will be further described below along the flowcharts shown in FIGS.
FIG. 6 shows an operation flowchart of the step detection device and step climbing device according to the present invention, and particularly shows from the setting of the initial information to the selection of the up step or the down step.

  First, as preconditions used for calculation of the calculation circuit 11 in the control device 10, in step S101, the radius r of the front wheel 101 and the maximum value F0 of the overcoming force are input. The maximum value F0 of the overcoming force indicates the maximum value of the traction force of the worker or the traction force by the driving force when the power device is used. When the step height h is smaller than the wheel radius r, as shown in the graph of FIG. 11 described later, the traction force for exceeding the step with only the wheel is small.

  Next, in step S102, the amount of load applied to the front wheel 101 and the rear wheel 103, which is performed when the mounted object is placed, is measured by a load sensor (not shown). In this case, in the state where the bogie caster front wheel 201 and the bogie caster rear wheel 202 of the bogie 200 are not in contact with each other, each load amount when only the front wheel 101 and the rear wheel 103 are supported is measured, and the front wheel load is expressed as W21, The rear wheel load is stored as W22.

  Next, the load applied to the front wheel 101 and the rear wheel 103 is measured in a state where all the wheels are grounded uniformly, and the front wheel load is stored as W23 and the rear wheel load is stored as W24. By comparing the measured values of the front wheel load and the rear wheel load during conveyance with the stored loads W21, W22, W23, and W24 described above, FIGS. 4A to 4F and FIGS. It can be determined in which state of (f).

Next, in step S103, the front wheel 101 is brought into contact with the corner of the step, and at this time, the arithmetic circuit 11 receives the contact acceleration from the step received by the front wheel 101 from the acceleration sensor 300 as the biaxial acceleration components ax and az. Accordingly, the drag direction angle θ, the step height h, and the overcoming force F are calculated.
First, the drag direction angle θ is obtained from the biaxial acceleration components ax and az as shown in FIG.

Next, the step height h is calculated using a drag A from the step acting on the wheels of the step climbing apparatus according to the present invention, a load W applied to the driving wheel, a step climbing force F, and a drag direction angle θ. This will be described with reference to FIG. 9 showing the relationship.
In FIG. 9, a caster wheel 400 having a load resistance of 2500 N and a wheel outer diameter of 200 mm is a caster having a general configuration in which a rubber material is used for the outer ring portion and a steel plate press material is used for the other portions. A caster axle 401 is located at the center of the caster wheel 400 and is attached to a connecting member 403 of the carriage by a caster support member 402.

As described above, when the drag direction angle θ is obtained, the step height h is obtained by the following equation.
h = r (1-cos θ) (1)
Further, regarding the step overcoming force F, with respect to the drag vector direction A based on the contact point between the step and the outer ring portion of the caster, the component force of the load W and the component force of the overcoming force F are considered, and the conditions for making both equal It can be considered as a condition to overcome a step. Therefore, the following equation is established.
F · cos θ = W · sin θ ··· Equation (2)
If this is deformed, the step overcoming force F is obtained by the following equation.
F = W · tan θ ········ Equation (3)

The graph of FIG. 10 is a graph showing the relationship from 0 degree to 90 degrees in the direction angle θ of the drag generated at the time of step contact with respect to the ratio h / r between the step height h and the wheel radius r. .
FIG. 11 shows this vertical axis θ at another angle, and the coefficient K corresponds to tan θ in the above equation (3), and corresponds to the load applied to the drive wheels 101 and 103. It shows how many times overcoming power is required.

For example, when overcoming a step height of 10 mm with a wheel radius of 100 mm, h / r is 0.1 and the coefficient K is 0.48, and the traction force for overcoming the step is more than half of the load W applied to the wheel. It shows that it is necessary. Further, it is shown that if the step height h and the drag direction angle θ are known, a traction force for getting over the step can be obtained. In other words, the upper limit value of the step height h at which the step climbing device is started may be changed in accordance with the load of the load, and the efficiency of the transfer work can be improved.

In this way, when the drag direction angle θ is obtained in step S103, in step S104, it is determined whether the step is up or down based on the value of θ, and the step moves over the step (steps S105 and S106). .
For example, in the case of FIG. 1A, it can be seen that the drag direction angle θ is on the positive side and is stepped up. Further, in the case of FIG. 1B, it can be seen that the drag direction angle θ is on the negative side and is step-down.

FIG. 7 shows a step-up operation following step S105 in FIG.
First, in step S201, the climbing force F is compared with the default climbing force F0 to determine whether or not a step climbing operation is necessary. If F ≧ F0, the step climbing operation is continued.
The case of F <F0 corresponds to the case where the step height is small and the load is small, and the traction work by the front wheel 101 and the rear wheel 103 is advanced without going through the lifting / lowering process of the carriage 200, and the overpass operation is omitted.

In step S202, the rotation of the front and rear wheels 101 and 103 is stopped, the front wheel lifting / lowering actuator 102 is driven, and the front wheel 101 is raised by the step height h (see FIG. 4A).
In step S203, the front and rear wheels 101 and 103 are driven, the step climbing device is advanced, and the front wheel 201 of the carriage 200 is moved to a position where it contacts the step (see FIG. 4B).

  In step S204, the rotation of the front and rear wheels 101 and 103 is stopped, and the front wheel elevating actuator 102 and the rear wheel elevating actuator 104 are simultaneously lowered by the step height h at the same speed. At this time, the carriage 200 rises by the step height h while remaining horizontal. Since the entire load is received by the front wheel 101 and the rear wheel 103, it is confirmed that the front wheel load is the initial setting W21 and the rear wheel load is the initial setting W22 (see FIG. 4C).

In step S205, the front and rear wheels 101 and 103 are driven, the step climbing device is advanced, and moved to a position where the rear wheel 103 of the carriage 200 contacts the step (see FIG. 4d).
In step S206, the rotation of the front and rear wheels 101, 103 is stopped, the rear wheel lifting actuator 104 is driven, and the rear wheel 103 is raised by the step height h (see FIG. 4 (e)).

  In step S207, the front and rear wheels 101 and 103 are driven, and the step climbing device is advanced to move all the wheels 101 to 104 until they contact the upper surface of the step height h (see FIG. 4 (f)).

  In step S208, the rotation of the front and rear wheels 101 and 103 is stopped, and the front and rear wheel elevating actuators 102 and 104 are driven so that the load received by the front wheel 101 is the initial setting W23 and the load received by the rear wheel is the initial setting W24. Then, the step climbing operation is finished by adjusting the ground contact state of the entire step climbing apparatus to be equal.

FIG. 8 shows a step-down process subsequent to step S106 in FIG.
First, in step S301, the step climbing apparatus is advanced to a position where the front wheel 101 can contact the lower surface of the step (see FIG. 5A).

The rotation of the front and rear wheels 101 and 103 is stopped, the front wheel lifting actuator 102 is driven, and the front wheel 101 is lowered until it contacts the lower surface of the step (see FIG. 5B).
In step S302, it is confirmed that the front wheel load is an initial setting W23 and the rear wheel load is an initial setting W24 (see FIG. 5B).

  In step S303, the step climbing device is moved backward to bring the front wheel 101 into contact with the step (see FIG. 5B). Then, the contact acceleration ax, az from the step received by the front wheel 101 is measured, and the drag direction angle θ, the step height h, and the overcoming force F are calculated and stored (see FIG. 5B). This step S303 may be omitted because there is step S103 in FIG.

  In step S304, the front and rear wheels 101 and 103 are driven and the step-over device is advanced. In step S305, when the front wheel load changes to the initial setting W21 and the rear wheel load changes to the initial setting W22, the front and rear wheels 101 and 103 are driven. Stop driving.

In step S306, when the cart 200 is lowered, the step climbing device is advanced to a position where the wheels 201 and 202 of the cart 200 can contact the lower surface of the step (see FIG. 5C).
In step S307, the rotation of the front and rear wheels 101, 103 is stopped, and the front wheel lifting actuator 102 and the rear wheel lifting actuator 104 are simultaneously raised by the step height h at the same speed. At this time, the carriage 200 is lowered by the step height h while being horizontal (see FIG. 5D).

In step S308, the front wheel 101 is driven to advance the step climbing device, and the rear wheel lifting / lowering actuator 104 is driven to ground the rear wheel 103 to the lower surface of the step (see FIGS. 5E and 5F).
In step S309, the front and rear wheel lift actuators 102 and 104 are set so that the rotation of the front and rear wheels 101 and 103 is stopped, and the load received by the front wheel 101 is the initial setting W23 and the load received by the rear wheel 103 is the initial setting W24. The step-down operation is finished by driving and adjusting so that the ground contact state of the entire step-over device is equalized.

Embodiment 2. FIG.
FIG. 12 shows a second embodiment of the step climbing apparatus according to the present invention.
FIG. 12A shows a state before the step-over device and the carriage are connected. The carriage 200 has two front wheels 201 and two rear wheels 202 fixed to the carriage 200, and shows a state in which a heavy object 500 is mounted.

  The step climbing device has a configuration in which the front wheel 101 and the front wheel lifting actuator 102, and the rear wheel 103 and the rear wheel lifting actuator 104 are attached to the base 111. It has a structure that can.

The base 111 has connecting portions 106 and 107, and after being inserted below the carriage 200, the carriage 200 and the base 111 of the climbing apparatus are firmly fastened.
In the step climbing device, the drive motor 108 and the power source 109 are concentrated at a position higher than the wheel near the bundle 110.
The driving force to the front and rear wheels 101, 103 and the lifting actuators 102, 104 of the step climbing device transmits the driving torque from the driving motor 108 to the reduction gear near the wheels via the wire.

FIG. 12B shows a state where the step-over device and the carriage are connected.
The number of wheels of the carriage is four and the number of wheels of the climbing device is two each of the front and rear wheels, and the heavy object 500 is transported by a total of eight wheels.

  During normal transportation, the vehicle travels with the load evenly distributed over the eight-legged wheels. In the process of climbing over the step, when supporting with 4 legs of the carriage and 2 legs of the front or rear wheel, all 6 legs, supporting with only 4 legs of the carriage, it may be supported with only 4 legs of the step overpass device .

  In each of the above embodiments, the direction of the drag generated by contact with the step may be detected using a biaxial load sensor instead of the biaxial acceleration sensor.

  100 base, 101 front wheel, 102 front wheel lifting actuator, 103 rear wheel, 104 rear wheel lifting actuator, 105 front wheel axle, 106 connecting part, 107 connecting part, 108 drive motor, 109 power supply, 110 handle, 111 base, 200 dolly, 201 wheel front wheel, 202 wheel rear wheel, 300 biaxial acceleration sensor, 400 caster wheel, 401 caster axle, 402 caster support member, 403 connecting member, 500 heavy object.

Claims (6)

An acceleration sensor that is attached to a portion that is in contact with the rotational axis of the drive wheel and detects acceleration in a biaxial direction perpendicular to the rotational axis of the drive wheel;
A control device for obtaining a drag direction angle from a biaxial component of drag acceleration obtained from the acceleration sensor and estimating a height of the step from the drag direction angle when a step of a traveling road and the driving wheel contact each other; A level difference detecting device. A step climbing device comprising the step detecting device according to claim 1, wherein the driving wheel is disposed on the front side and the rear side of the front wheel and the rear wheel of the carriage, respectively.
An actuator for changing the height of the drive wheel,
The control device determines, from the value of the drag direction angle, whether the step with which the front drive wheel is in contact is an upward direction or a downward direction with respect to the traveling direction of the carriage, and then determines the height of the step. A step-over device that operates the actuator. The actuator includes a load sensor that detects a load applied to the driving wheel before the step and the driving wheel contact each other.
The control device calculates a force necessary to overcome the step from the load and the drag direction angle, and a force necessary to overcome the step is less than a force that can be applied for conveyance. In this case, the step climbing device according to claim 2, wherein the step climbing is performed only by the driving wheel without using the actuator. The step climbing device according to claim 2, wherein when the actuator is operated with respect to the step, the control device makes the lifting speed of the front and rear drive wheels the same. The step climbing apparatus according to claim 2, wherein a load sensor that detects a biaxial load is used instead of the acceleration sensor. The level | step climbing apparatus of Claim 2. It has a structure connected so that attachment and removal are possible in the lower part of the said trolley | bogie.

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