Apparatus walking with two legs, walking control apparatus, and walking control method thereof

• US 20040051493A1
• Filed: 06/23/2003
• Published: 03/18/2004
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: Japan Science & Technology Trading Co. Limited
• Original Assignee: Japan Science & Technology Trading Co. Limited
• Inventors: Furuta, Takayuki, Tomiyama, Ken, Kitano, Hiroaki
• Granted Patent: US 6,943,520 B2
• Time in Patent Office: Days
• US Class Current: 318/568.12
• CPC Class Codes: B62D 57/032 with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid B62D57/024 takes precedence

Abstract

Disclosed is a biped walking mobile system or apparatus, typically a biped walking robot, which achieves walk stability without altering a preestablished gait, namely path of movement for each of joint region, as well as a walk controller and a work control method therefor. The biped walking mobile apparatus, advantageously made as a humanoid robot with an upper body (11) as its main body having its head and a pair of hands, has in its lower part a pair of leg portions (13L, 13R) attached thereto so as to be each pivotally movable biaxially, each of the leg portions having a knee portion (12L, 12R) in its midway and a foot portion (14L, 14R) at its lower end, the foot portions being attached to its corresponding leg portion so as to be pivotally movable biaxially, and includes drive means associated with the leg, knee and foot portions for pivotally moving them, respectively, a gait former 8249 for forming gait data including data for a target angular path, data for a targeted angular velocity and data for a targeted angular acceleration, and a walk controller (30) for controlling respective driving actions of the drive means on the basis of the gait data, the walk controller including a ZMP compensator (32), the ZMP compensator including: a ZMP sensor (23L, 23R) for detecting ZMP for each the feet portions (14L, 14R), a ZMP converter (35) for computing a ZMP target value on the basis of the gait data from the gait former, and a ZMP compensating stage (36) for comparing the actual measurement value of ZMP detected by the ZMP sensor with the ZMP target value from the ZMP converter to modify the targeted angular velocity and acceleration in the gait data from the gait former and thereby to compensate or correct the ZMP target value. Thus, with the targeted angular path of movement in the gait data which remains unaltered when the ZMP target value is compensated, no case is there that the paths of movement of various parts of the mobile apparatus or robot such as its main body or legs come off those preestablished in the gait data Accordingly, even in case, e. g., a the biped mobile apparatus has its free foot landing positions unalterable such as in stepping-stones, or an obstacle needed to be stepped over or passed under, it an achieve walk control with certainty.

Claims

1. A biped walking mobile system, comprising:

a main body having in its lower part a pair of leg portions attached thereto so as to be each pivotally movable biaxially, each of the leg portions having a knee portion in its midway and a foot portion at its lower end, the foot portions being attached to its corresponding leg portion so as to be pivotally movable biaxially,

drive means associated with said leg, knee and foot portions for pivotally moving them, respectively,

a gait former responsive to a demand for motion for forming gait data including data for a target angular path, data for a targeted angular velocity and data for a targeted angular acceleration, and

a walk controller for controlling respective driving actions of said drive means on the basis of said gait data, said walk controller including a ZMP compensator, characterized in that said ZMP compensator includes;

a ZMP sensor for detecting ZMP for each of said foot portions,

a ZMP converter for computing a ZMP target value on the basis of the gait data from said gait former, and

a ZMP compensating stage for comparing an actual measurement value of ZMP detected by said ZMP sensor with the ZMP target value from said ZMP converter to modify the targeted angular velocity and acceleration in the gait data from said gait former and thereby to compensate or correct said ZMP target value.

2. A biped walking mobile system as set forth in claim 1, characterized in that said biped walking mobile system is a humanoid robot having said main body provided with a head portion and a pair of hand portions.

3. A biped walking mobile system as set forth in claim 1 or claim 2, characterized in that said ZMP compensating stage comprises:

a virtual ZMP target value former for comparing an actual measurement value of ZMP detected by said ZMP sensor with the ZMP target value from said ZMP converter to form a virtual ZMP target value,

a parameter former for forming a force of inertia control parameter for use in forming the ZMP virtual target value from the ZMP target value to compensate the latter, and a stabilizing filter for compensating the ZMP target value on the basis of the force of inertia control parameter from said parameter former.

4. A biped walking mobile system as set forth in claim 3, characterized in that said ZMP virtual target value former is adapted to judge if the formed ZMP virtual target value lies within a compensatable limit.

5. A biped walking mobile system as set forth in claim 4, characterized in that if the formed ZMP virtual target value is found to exceed the compensatable limit, said ZMP virtual target value former is adapted to repeat forming a ZMP virtual target value.

6. A walk controller for a biped walking mobile apparatus which includes:

a main body having in its lower part a pair of leg portions attached thereto so as to be each pivotally movable biaxially, each of the leg portions having a knee portion in its midway and a foot portion at its lower end, the foot portions being attached to its corresponding leg portion so as to be pivotally movable biaxially,

drive means associated with said leg, knee and foot portions for pivotally moving them, respectively, and

a gait former responsive to a demand for motion for forming gait data including data for a target angular path, data for a targeted angular velocity and data for a targeted angular acceleration, whereby said walk controller controls respective driving actions of said drive means on the basis of said gait data, said walk controller having a ZMP compensator and being characterized in that said ZMP compensator includes;

a ZMP sensor for detecting ZMP for each of said foot portions,

a ZMP converter for computing a ZMP target value on the basis of said gait data from said gait former, and

a ZMP compensating stage for comparing an actual measurement value of ZMP detected by said ZMP sensor with the ZMP target value from said ZMP converter to modify the targeted angular velocity and acceleration in the gait data from said gait former and thereby to compensate or correct said ZMP target value.

7. A walk controller for a biped walking mobile apparatus, as set forth in claim 6, characterized in that said ZMP compensating stage comprises:

a virtual ZMP target value former for comparing the actual measurement value of ZMP detected by said ZMP sensor with the ZMP target value from said ZMP converter to form a virtual ZMP target value,

a parameter former for forming a force of inertia control parameter for use in for forming the ZMP virtual target value from the ZMP target value to compensate the latter, and

a stabilizing filter for compensating the ZMP target value on the basis of the force of inertia control parameter from said parameter former.

8. A walk controller for a biped walking mobile apparatus, as set forth in claim 7, characterized in that said ZMP virtual target value former is adapted to judge if the formed ZMP virtual target value lies within a compensatable limit.

9. A walk controller for a biped walking mobile apparatus, as set forth in claim 8, characterized in that if the formed ZMP virtual target value is found to exceed the compensatable limit, said ZMP virtual target value former is adapted to repeat forming a ZMP virtual target value.

10. A walk control method for a biped walking mobile apparatus which includes:

a main body having in its lower part a pair of leg portions attached thereto so as to be each pivotally movable biaxially, each of the leg portions having a knee portion in its midway and a foot portion at its lower end, the foot portions being attached to its corresponding leg portion so as to be pivotally movable biaxially, drive means associated with said leg, knee and foot portions for pivotally moving them, respectively, and a gait former responsive to a demand for motion for forming gait data including data for a target angular path, data for a targeted angular velocity and data for a targeted angular acceleration, the method controlling respective driving actions of said drive means on the basis of said gait data, the method being characterized in that the it in performing a ZMP compensation comprises;

the first step of detecting ZMP for each of said foot portions by a ZMP detecting sensor;

the second step of computing a ZMP target value at a ZMP converter on the basis of said gait data from said gait former; and

the third step of comparing a ZMP actual measurement value detected by said ZMP detecting sensor with the ZMP target value and modifying the target angular velocity and angular acceleration in the gait data from said gait former, thereby compensating said ZMP target value.

11. A walk control method for a biped walking mobile apparatus as set forth in claim 10, characterized in that the third step includes the sub-steps of:

comparing the ZMP actual measurement value detected by said ZMP sensor with the ZMP target value from said ZMP converter to form a ZMP virtual target value, forming a force of inertia control parameter for use in forming the ZMP virtual target value from said ZMP target to compensate the latter, and compensating the ZMP target value at a stabilizing filter on the basis of said force of inertia control parameter.

12. A walk control method for a biped walking mobile apparatus as set forth in claim 11, characterized in that the step of forming the ZMP virtual target value includes judging if the formed virtual target value lies within a compensatable limit.

13. A walk control method for a biped walking mobile apparatus as set forth in claim 12, characterized in that the step of forming the ZMP virtual target value includes repeating forming a ZMP virtual target value if the formed ZMP virtual target value is found to exceed said compensatable limit.