JP2007044836A - Leg type biped robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leg type biped robot capable of solving a problem of what kind of norm should be taken as a basis of posture correction during a period of a robot taking off and grounding on a floor as a change of a state of the robot in the middle of jumping is conventionally handled only by simple judgement of whether it takes off from or grounds on the floor. <P>SOLUTION: This robot has an acceleration sensor 9. A foot part 6 of the robot has a switch to detect whether a sole part a back surface of which grounds on the ground grounds on the ground or not. A joint actuator is provided on a leg part 5, and its joint angle is controlled by a joint angle control means. A posture control part provided in the robot drives and controls the joint actuator so as to follow a target joint angle by carrying out center-of-gravity position correction in a direction where grounding impact of the robot is reduced and by generating a control signal of the target joint angle to be in the corrected center-of-gravity position in accordance with an acceleration detection value of the acceleration sensor 9 at an instant when the sole part grounds on the floor after taking off. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a legged biped robot, and more particularly to a legged biped robot that realizes the body mechanism and operation of a bipedal animal such as a human by real-time angle control of a joint actuator of a leg.

  A legged biped robot that consists of a lower limb with two movable legs and an upper body arranged above the lower limb, and realizes various motion patterns by movement of the lower limbs, such as four legs or six legs Although it is unstable and difficult to control posture and walking, compared to conventional legged robots, it can move flexibly, such as moving up and down stairs and getting over obstacles. A legged biped robot with these characteristics is controlled so as to mitigate the impact received from the floor surface when the robot is landing after performing a motion pattern such as walking, running, and jumping. (For example, refer to Patent Document 1).

  In this legged biped robot described in Patent Document 1, in order to correct the position of the center of gravity at the time of getting out and landing, the posture of the robot is made to correspond to the posture of the robot by bending and extending the joint, and the impedance of the joint actuator is changed. It stabilizes and relieves impact during landing.

JP 2001-138273 A

  However, in the conventional legged biped robot described in Patent Document 1 described above, a technique for stabilizing the posture and mitigating the landing impact by changing the center of gravity position using the joint extension of the robot during the flooring and landing periods is described. However, for example, the robot state change during jumping is handled only by the judgment of whether to get off or landing, and a specific method for correcting posture based on the norm during robot leaving or landing Is not explicitly stated.

  The present invention has been made in view of the above points, and provides a legged biped robot capable of stabilizing the motion performance by performing posture correction based on the acceleration of the robot immediately before reaching the ground completely. For the purpose.

In order to achieve the above object, the present invention comprises an upper body part and a lower body part, and the upper body part includes at least a body part, a head attached to the upper part of the body part, and both side surfaces of the body part. The lower body part is composed of a pair of legs that are movably attached, and the lower body part is a pair of legs that are attached to the body part, and a leg that is movably attached to the other end of the leg part and the back surface is grounded to the ground. A leg type that consists of a pair of feet with a base, and the legs are structured by connecting a plurality of joint actuators that can be controlled to an arbitrary angle, controlling the movement of the joint actuators to form a desired posture A biped robot,
Acceleration detecting means for detecting acceleration according to the movement of the robot installed in the torso, switch means for detecting the landing or leaving state of the foot base, provided on the foot base, and the foot by the switch means Based on the acceleration detection value of the acceleration detection means at the timing when it is detected that the base portion changes from the leaving state to the landing state, a control signal for controlling the posture in a direction in which the landing impact of the robot is reduced It is characterized by having posture control means to be generated and joint angle control means for controlling joint angles of a plurality of joint actuators based on control signals generated by the posture control means.

  In this invention, the timing of the moment of landing after the robot leaves the floor is detected by the switch means, and the landing impact of the robot is reduced by the attitude control means based on the acceleration detection value of the acceleration detection means at the time of detection of the switch means. Since the control signal for controlling the posture in the direction to be generated is generated and supplied to the joint angle control means, the gravity center position correction in the direction in which the landing impact of the robot is reduced when the robot is completely landed It can be performed.

  According to the present invention, based on the acceleration detection value at the moment of landing after the robot leaves the floor, the posture control is performed in a direction in which the landing impact of the robot is reduced, and the center of gravity position corrected by the posture control is obtained. By controlling the joint actuator to the joint angle, the center of gravity is corrected in the direction that reduces the landing impact of the robot when the robot has completely landed. Landing can be realized.

  Next, embodiments of the present invention will be described with reference to the drawings. 1A and 1B are a front view and a left side view of an embodiment of a legged biped robot according to the present invention. As shown in FIGS. 1A and 1B, the legged biped robot of this embodiment includes a body part 1, a waist part 2 movably attached to the lower part of the body part 1, and a body part 1. An upper body portion 7 including two arm portions 3 movably attached to both side surfaces of the body, a head portion 4 attached to an upper portion of the body portion 1, two leg portions 5, and the other leg portions 5. It is comprised from the lower body part 8 which consists of the two leg | foot parts 6 attached to the end so that movement was possible.

  The end of the leg 5 opposite to the end to which the foot 6 is attached is movably attached to the waist 2. The center of gravity of the entire robot is approximately in the vicinity of the center of the body 1, and an acceleration sensor 9 for detecting the acceleration in the center of gravity direction is provided near the center. Each of the above parts is connected by a joint having a degree of freedom, and each of the two legs 5 has a hip joint yaw axis 10, a hip roll axis 11, a hip pitch axis 12, a knee pitch axis 13, an ankle as shown in FIG. The roll shaft 14 and the ankle pitch shaft 15 have a total of six degrees of freedom.

  On the other hand, as shown in FIG. 3, the foot portion 6 has a generally rectangular foot base portion 16 via a stroke type push switch 18 disposed at approximately four corners between the foot base portion 16 and the foot upper structure 17. Thus, the structure is held by the foot upper structure 17 so as to allow the switch 18 to move in the vertical direction on the ground surface. The switch 18 has an appropriate elasticity in its movable range, and maintains an urging force enough to separate the foot base 16 from the foot upper structure 17 by the elasticity while the robot is swinging.

  Thus, when the robot leaves the floor where the total weight of the robot does not apply to the foot 6, as shown by 18a in FIG. 3 (a), the actuator part of the switch 18 protrudes the maximum distance and is in the switch-off state. As shown by 18b in FIG. 8B, the switch 18 is turned on when the actuator portion of the switch 18 is slightly pushed, and when the landing (grounding) is completed, the entire weight of the robot is applied to the foot portion 6. As indicated by 18c in (c), the actuator portion of the switch 18 is switched on by being pushed the maximum distance. Note that the structure of the switch 18 itself is not directly related to the gist of the present invention, and the description thereof is omitted.

  In the present embodiment, for example, a signal processing device is built in the body portion 1. FIG. 4 shows a block diagram of an embodiment of this signal processing apparatus. In the figure, the posture control unit 21 outputs a posture control signal for controlling the posture of the robot. The sensor processing device 22 stores the acceleration information of the acceleration sensor 9 at the time when the switch 18 is turned on and outputs it to the attitude control unit 21. The joint angle control unit 23 controls the joint angle of the joint actuator 24. Further, the joint actuator 24 is a joint that connects the body part 1 and the arm part 3, a joint that connects the upper body part 7 and the lower body part 8, and a hip joint arm provided on the two leg parts 5 shown in FIG. The shaft 10, the hip joint roll shaft 11, the hip joint pitch shaft 12, the knee pitch shaft 13, the ankle roll shaft 14, the ankle pitch shaft 15, etc., and these angles (joint angles) are controlled by a control signal. . The controlled joint angle is fed back to the joint angle control unit 23.

  Next, the operation of the present embodiment will be described. Here, a jump landing operation in the vertically upward direction will be described as an example of the operation. That is, as shown in FIG. 5A, the robot 20 shown in FIG. 1 jumps and both feet separate from the ground 21, and then naturally falls due to its own weight, and landing (landing) as shown in FIG. 5B. Then, in this embodiment, as shown in FIG. 5C, the leg 5 is further bent to correct the center of gravity.

  In the case of this jump landing operation, the speed of the robot and the switch timing of the switch 18 when the gravity center position correcting operation shown in FIG. 5C is not performed are as shown in FIG. That is, while the robot jumps as shown in FIG. 5 (a) and both feet move away from the ground and rise according to the initial speed obtained when leaving the floor, the speed of the robot is shown by I in FIG. 6 (a). However, when entering a natural fall state due to its own weight, the speed increases in the negative direction, and even after the completion of the ground contact at time t2, the impact at the time of landing cannot be absorbed and damped and oscillated. Note that, as indicated by II in FIG. 6A, the switch 18 is turned on as shown in FIG. 3B at time t1 at the moment of grounding, and thereafter the ON state shown in FIG. 3C continues. .

  On the other hand, in this embodiment, while the robot jumps as shown in FIG. 5A and both feet move away from the ground and rise according to the initial speed obtained at the time of getting off, the robot speed is as shown in FIG. ) Is increased in the positive direction as indicated by III, and then the point where the speed increases in the negative direction when entering a natural fall state due to its own weight is the same as when the center of gravity position correction is not performed. When the robot starts landing at the time t2 shown in FIG. 6B as shown in FIG. 5B, a part or the whole of the foot base portion 16 shown in FIG. Any one or more of the four switches 18 arranged at approximately four corners between 16 and the foot upper structure 17 are simultaneously turned on as shown in FIG. The on time of the first switch that is turned on among the four switches 18 is indicated by t1 in FIG. 6B. The switch timing of the switch 18 is indicated by II in FIG. 6 (b), which is the same as the switch timing of FIG. 6 (a).

  The sensor processing device 22 in the block diagram of FIG. 4 in the robot of the present embodiment stores the value (acceleration information) of the acceleration sensor 9 at the time t1 when the first switch among the four switches 18 is turned on, and the posture Output to the control unit 21. The value (acceleration information) of the acceleration sensor 9 at this time means the robot drop speed immediately before the robot reaches the floor completely.

  Next, the posture control unit 21 of the robot sets the detected drop speed at the on-time t1 of the switch 18 so that the center of gravity absorbs the landing impact with respect to the preset posture, that is, the posture in which the robot squats down. A corresponding center-of-gravity position correction amount is determined. Based on this, the posture control unit 21 resets the leg joint angle target value to be supplied to the joint angle control unit 23. The joint angle control unit 23 follows the reset leg joint angle target value so that the joint actuator 24 (here, 11 to 15 of the six axes 10 to 15 of the leg 5 shown in FIG. 2). Control the joint angle. The actual joint angle of the joint actuator 24 is fed back to the joint angle control unit 23 so that the joint actuator 24 is accurately controlled to the target value so that the robot is in a posture of squatting and absorbs the landing impact.

  With the above operation, the robot obtains the center-of-gravity position correction as a stability standard after landing according to the falling speed at the time of landing, and can realize a stable and appropriate squatting operation as shown in FIG. Thereby, the speed of the robot converges to 0 in a short time after time t2, as indicated by III in FIG. 6B. As described above, according to this embodiment, the robot determines the timing of getting out and landing clearly by the structure of the robot and detects the robot speed immediately before the robot reaches the landing completely by the acceleration sensor 9 of the robot. As a result, the robot can achieve a stable landing with minimum necessary posture correction.

  In this embodiment, after the robot jumps and before complete landing (timing to receive all floor reaction force), the center of gravity position correction becomes a stability criterion after landing according to the falling speed at the time of landing. The control of the joint actuator 24 based on the center-of-gravity position correction amount does not end at the time of complete landing, and actually the control continues even after complete landing, but the speed of the robot is at time t2. Thereafter, as indicated by III in FIG. 6B, it converges to 0 in a short time.

  In addition, this invention is not limited to the above embodiment, The following various examples are included.

  FIG. 7 shows a schematic external view of a legged biped robot according to the first embodiment of the present invention. The legged biped robot 25 of the present embodiment is a robot that realizes gymnastics. For example, after using the iron bar 26 to imitate the advanced skill of a gymnast, or after performing a technique that cannot be performed by humans. Landing is difficult, and if it is a normal robot, it will often fool or fall. However, the legged biped robot 25 of the present embodiment basically performs landing by buffering the impact with a joint such as a knee, and the center of gravity is within a relatively long period of delicate balance at the time of landing. By moving, it can be made difficult to fall down.

  FIG. 8 is a schematic external view of a legged biped robot according to a second embodiment of the present invention. The legged biped robot 28 of this embodiment is a robot that has a spring 29 under the foot and jumps using the elastic force of the spring 29. The legged biped robot 28 according to the present embodiment can move the center of gravity to the optimal position within a relatively long period from the time of landing until the spring 29 contracts to the maximum, thereby making it difficult to fall down. .

  FIG. 9 is a schematic external view of a legged biped robot according to a third embodiment of the present invention. The legged biped robot 30 of the present embodiment is a robot that acts using a trampoline 31. The legged biped robot 30 has a period from when the foot reaches the trampoline 31 after the jump until the next jump from the trampoline 31 until the trampoline 31 reaches the lowest point due to the impact of landing. There is a relatively long time to use the power to restore.

  Using this time, the legged biped robot 30 determines the center-of-gravity position correction amount according to the falling speed, resets the leg joint angle target value based on this, and sets the target joint angle to the reset target joint angle. By controlling the leg 5 having the six axes 10 to 15 shown in FIG. 2 so as to follow, the center of gravity can be moved to the optimum position for the next jump. The legged biped robot 30 may be provided with a switch corresponding to the switch 18 not only at the foot but also at the buttocks and the upper body.

It is the front view and left view of one embodiment of this invention. It is a figure which shows the detailed structure of an example of the leg part in FIG. It is structure explanatory drawing of an example of the leg part in FIG. It is a block diagram of one embodiment of a signal processing device provided in the robot of the present invention. It is a figure which shows the jump landing operation | movement to the vertical upward direction of one embodiment of this invention. It is a figure which shows the relationship between a robot speed and switch timing in contrast with the embodiment of this invention with a center-of-gravity position correction | amendment and the prior art without center-of-gravity position correction. It is a schematic external view of Example 1 of the robot of the present invention. It is a general | schematic external view of Example 2 of the robot of this invention. It is a schematic external view of Example 3 of the robot of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torso part 2 Lumbar part 3 Arm part 4 Head part 5 Leg part 6 Foot part 7 Upper body part 8 Lower body part 9 Acceleration sensor 10 Hip joint axis 11 Hip joint roll axis 12 Hip joint pitch axis 13 Knee pitch axis 14 Ankle roll axis 15 Ankle pitch Axis 16 Foot base 17 Upper foot structure 18 Push switch 21 Posture control unit 22 Sensor processing device 23 Joint angle control unit 24 Joint actuator

Claims (1)

The upper body part is composed of an upper body part and a lower body part, and the upper body part includes at least a body part, a head attached to an upper part of the body part, and a pair of arms movably attached to both side surfaces of the body part. The lower body part includes a pair of leg parts having one end attached to the body part and a foot base part movably attached to the other end of the leg part and having a back surface grounded to the ground. A leg-type biped robot that has a structure in which a plurality of joint actuators that can be controlled at an arbitrary angle are connected, and a desired posture is formed by controlling the operation of the joint actuators. There,
Acceleration detecting means installed in the body part for detecting acceleration according to the movement of the robot;
Switch means for detecting the landing or getting-off state of the foot base, provided on the foot base;
Based on the acceleration detection value of the acceleration detection means at a timing when the switch means detects that the foot base portion has changed from the bed leaving state to the landing state, the posture in a direction in which the landing impact of the robot is reduced Attitude control means for generating a control signal for controlling
A legged biped robot, comprising: joint angle control means for controlling joint angles of the plurality of joint actuators based on the control signal generated by the posture control means.

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