JP2005046950A - Four-leg mobile robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a four-leg mobile robot capable of easily and stably getting over step difference and going up and down the stairs besides traveling, with simple constitution. <P>SOLUTION: Hip joints 1a, 1b, 1c, 1d arranged almost in a straight line are provided with four extensible legs 3a, 3b, 3c, 3d rotatably forward and backward, and the tip of each of the legs 3a, 3b, 3c, 3d is provided with a travel device 39. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a four-legged mobile robot that can stably run on a flat ground, climb over a level difference, and move up and down stairs with a simple configuration.

  Various unattended mobile robots have been proposed for dangerous places where people cannot stop, home automation, office transportation and security, and factory patrols.

As a method of moving the robot, there is a leg-wheel type having a high-speed moving performance of wheels and a step-over performance of legs. For example, Japanese Patent Application Laid-Open No. 2004-133867 discloses a vehicle that travels with wheels provided on each leg of a legged mobile robot, and steps such as stairs are moved up and down by appropriately raising and lowering the legs.
JP 59-152080 A

  However, if there are four or more legs, when moving up and down the step, each leg has a degree of freedom, so the mechanism and control for raising and lowering each leg becomes complicated and the weight of each leg increases. However, there is a problem that the moving speed decreases.

  On the other hand, in the case of a two-legged structure like a human being, the mechanism is relatively simple, but the degree of freedom is reduced, it is difficult to obtain the center of gravity of the robot body, and the control becomes very complicated. There is a problem that the weight of the device for driving the movement increases, and it is difficult to drive simply or efficiently.

  There are also three legs with a central leg and left and right legs that allow you to move over the stairs and move up and down the stairs while moving the center of gravity like walking with crutches. Although this mechanism is also relatively simple in mechanism, there is a problem that the robot is likely to fall down due to the action of a slight external force, slip, etc. because there is a state where it is supported at one point in the front-rear direction when moving the center of gravity.

  An object of the present invention is to provide a four-legged mobile robot with a simple configuration that can easily and stably move over steps other than running and climb up and down stairs.

  According to the first aspect of the present invention, the four-leg movement is characterized in that the hip joints arranged substantially in a straight line are provided with four extendable legs that can be rotated forward and backward, and a traveling device is provided at the tip of each leg. Robots.

  According to a second aspect of the present invention, four hip joints are arranged substantially in a straight line, each of the four legs is attached to each hip joint, and the hip joints are connected to each other by a driving device. 2. The four-legged mobile robot according to claim 1, wherein the legs can be rotated separately or simultaneously, and the outer two legs can be rotated separately or simultaneously.

  The invention according to claim 3 is characterized in that a foot is rotatably attached to each leg via an ankle shaft, and a traveling device is provided on the foot. This relates to a legged mobile robot.

  According to a fourth aspect of the present invention, there is provided the four-legged mobile robot according to the third aspect, wherein one actuator is provided for both the rotation of the foot and the driving of the traveling device. .

  According to the present invention, the hip joints arranged substantially in a straight line are provided with four extendable legs that can be rotated back and forth, and the traveling device is provided at the tip of each leg. Even when ascending and descending, three points can always be supported by three legs, so that stable movement is always possible.

  Furthermore, since four hip joints are arranged substantially in a straight line, and a driving device is arranged between the hip joints, the four legs can be rotated by the three driving devices. Weight can be reduced.

  In addition, since the foot is rotatably attached to each leg via the ankle shaft and the running device is provided on the foot, the foot can be firmly supported by the foot when climbing over a step or going up and down the stairs.

  In addition, since one actuator that combines the rotation of the foot and the driving of the traveling device is provided, the weight of the robot itself can be reduced by reducing the number of actuators.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic front view showing an example of the four-legged mobile robot of the present invention, and FIG. 2 is a side view showing a state where the four-legged mobile robot shown in FIG. 1 and 2, reference numerals 1a and 1b denote hip joints linearly connected by a driving device 2a, and inner legs 3a and 3b that can be expanded and contracted are attached to the hip joints 1a and 1b, respectively. . The inner legs 3a and 3b are connected to a fixed part 4 so that an extendable leg 5 can be driven to extend and contract, and the fixed part 4 is fixed to the hip joints 1a and 1b.

  A hip joint 1c is connected to the hip joint 1a in a straight line via a drive device 2b, and an extensible / extensible leg 3c is attached to an end of the hip joint 1c. Further, a hip joint 1d is connected to the hip joint 1b in a straight line via a driving device 2c, and an extensible leg 3d is attached to the end of the hip joint 1d. The outer legs 2c, 3d have a fixed portion 6 fixed to the hip joints 1c, 1d, and an extendable leg 7 is connected to the fixed portion 6 so as to be expanded and contracted.

  The hip joints 1a, 1b, 1c, and 1d may be connected to each other independently by the driving devices 2a, 2b, and 2c, or provided with penetrating shafts on the hip joints 1a, 1b, 1c, 1d may be rotatably provided.

  In the figure, 8 is a robot body, and the robot body 8 may be attached to the hip joints 1a, 1b, 1c, 1d, or the inner two legs 3a, 3b may be fixed. It may be composed of two main bodies fixed to the portion 4.

  3 and 4 show an example of the configuration of the lower ends of the legs 3a, 3b, 3c and 3d. The left and right ankle shafts 49 are provided on a bracket 48 fixed to the legs 3a, 3b, 3c and 3d. A foot 38 is rotatably attached to the ankle shaft 49. Further, a traveling device 39 having two wheels 39a and 39b attached thereto via a wheel shaft 40 is provided before and after the rotation direction of the foot portion 38. A crawler may be used as the traveling device 39. The left and right ankle shafts 49 are provided with a drive shaft 50 that is rotatably supported through the center of the ankle shaft 49, and a belt or a chain or the like is provided between the drive shaft 50 and the wheel shaft 40. The power transmission member 51 is connected. Further, one actuator 52 is provided on the legs 3 a, 3 b, 3 c, 3 d, and a driven bevel gear 55 that meshes with a drive bevel gear 54 provided on a rotation shaft 53 of the actuator 52 is provided on the drive shaft 50.

  Further, the leg portion 38 is provided with wheel restraining means 56 that restrains the rotation of the wheels 39a and 39b. The wheel restraining means 56 in FIG. 1 shows a case of a brake device 57 that restrains the rotation of the drive shaft 50 with respect to the foot portion 38. In addition to the brake device 57, a motor may be used for the wheel restraining means 56.

  The operation of the above embodiment will be described below.

  As shown in FIG. 1, FIG. 2 and FIG. 5, the four legs 3a, 3b, 3c, 3d are separated by focusing on the straight hip joints 1a, 1b, 1c, 1d by driving the driving devices 2a, 2b, 2c. It is possible to perform a four-legged walk that rotates at the same time, and to perform a two-legged walk that simultaneously rotates the inner legs 3a and 3b and simultaneously rotates the outer legs 3c and 3d.

  5 and 6 show the four-legged walking mode with the legs 3a, 3b, 3c and 3d, and FIGS. 2 and 7 simultaneously rotate the inner legs 3a and 3b and the outer legs 3c and 3d. The biped walking mode is shown, and in FIGS. 6 and 7, white represents a free leg (a leg away from the ground) and black represents a grounded leg (a leg in contact with the ground).

  In the four-legged walking mode of FIGS. 5 and 6, as shown in steps S <b> 1 to S <b> 5, the three-legged support with the three legs installed can always move, so that stable walking is possible. Further, when the wheels 39a and 39b or the crawler traveling device 39 shown in FIGS. 3 and 4 are driven in this state, the vehicle can move at a high speed in a stable state.

  In addition, in the biped walking mode of FIGS. 2 and 7, as shown in steps S1 to S3, the center of gravity movement is performed to move over the stairs and move up and down the stairs while moving the center of gravity as in walking using a crutch. 3 and 4 are provided, and the wheel restraining means 56 is provided so that the rotation of the wheels 39a and 39b can be restrained. Stability by the foot 38 can be enhanced.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

2 is a schematic front view showing an example of a four-legged mobile robot. FIG. 2 is a side view showing a state where the four-legged mobile robot of FIG. 1 is moving up and down stairs. It is a cutting | disconnection front view which shows the structural example of the lower part of a leg. FIG. 4 is a left side view of FIG. 3. It is a side view which shows the state which performs 4 legged walking. FIG. 5 is a cut front view. It is a top view which shows the walk of 4 leg walk mode by a leg. It is a top view which shows the biped walking mode which rotates two inner legs and two outer legs simultaneously.

Explanation of symbols

1a, 1b, 1c, 1d Hip joint 2a, 2b, 2c Driving device 3a, 3b, 3c, 3d Leg 38 Foot 39 Running device 49 Ankle shaft 52 Actuator

Claims (4)

  A four-legged mobile robot characterized in that hip joints arranged substantially in a straight line are provided with four extendable legs that can be rotated back and forth, and a traveling device is provided at the tip of each leg.   Four hip joints are arranged substantially in a straight line, each of the four legs is attached to each hip joint, and the hip joints are connected to each other by a driving device, and the inner two legs can be rotated separately or simultaneously, The four-legged mobile robot according to claim 1, wherein the outer two legs can be rotated separately or simultaneously.   The four-legged mobile robot according to claim 1 or 2, wherein a foot is rotatably attached to each leg via an ankle shaft, and a traveling device is provided on the foot.   The four-legged mobile robot according to claim 3, wherein one actuator is provided for both the rotation of the foot and the driving of the traveling device.

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