Robot hand and control system, control method and control program for the same

• US 8,504,198 B2
• Filed: 05/13/2010
• Issued: 08/06/2013
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Takahashi, Kazuyuki, Waita, Hironori, Gomi, Hiroshi
• Primary Examiner(s): Jen, Ian
• Application Number:
  US12/779,298
• Publication Number:
  US 20100292837A1
• Time in Patent Office: 1,181 Days
• Field of Search: None
• US Class Current: 700/245
• CPC Class Codes: B25J 15/0009 comprising multi-articulated fingers, e.g. resembling a human hand
• CPC Class Codes: B25J 9/1612 characterised by the hand, wrist, grip control
• CPC Class Codes: G06N 3/008 based on physical entities controlled by simulated intelligence so as to replicate intelligent life forms, e.g. based on robots replicating pets or humans in their appearance or behaviour

Abstract

A robot hand has a pipe which is sufficiently flexible to allow a change in the cross-sectional area thereof according to the pressure of a fluid, thereby permitting a higher degree of freedom of the layouts of the pipe and a master cylinder connected through the pipe. Moreover, considerations are given to a change in the cross-sectional area of the pipe caused by a change in the pressure of the fluid in the pipe, thus making it possible to measure the position of a slave piston with high accuracy.

Claims

1. A control system of a robot hand having a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, the control system comprising:

a first arithmetic processor configured to calculate a basic position of the slave piston in a state, wherein a diameter of the pipe remains unchanged, on a basis of a measured position of the master piston and an area ratio of the master piston relative to the slave piston and also to calculate a displacement amount of the slave piston according to a change in a cross-sectional area of the pipe on a basis of a measured pressure of a fluid in the pipe, a length of the pipe, and a coefficient indicating flexibility of the pipe thereby to determine a result obtained by correcting the basic position by the displacement amount as the position of the slave piston; and

a second arithmetic processor configured to control the position of the master piston on a basis of the position of the slave piston determined by the first arithmetic processor.

2. The control system according to claim 1, wherein

the robot hand further comprises a motor which moves the master piston forward and backward by transmitting a force through an intermediary of a speed reduction mechanism, and an encoder which outputs a signal based on a rotational position of the motor, and

the first arithmetic processor is configured to measure a position of the master piston on a basis of a rotational position of the motor based on an output signal of the encoder and a speed reduction ratio of the speed reduction mechanism.

3. A robot hand, comprising:

a plurality of finger mechanisms extended from a palm portion;

a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward;

a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward; and

a control system,

wherein the control system comprises;

a first arithmetic processing element configured to calculate a basic position of the slave piston in a state, wherein a diameter of the pipe remains unchanged, on a basis of a measured position of the master piston and an area ratio of the master piston relative to the slave piston and also to calculate a displacement amount of the slave piston according to a change in a cross-sectional area of the pipe on a basis of a measured pressure of a fluid in the pipe, a length of the pipe, and a coefficient indicating flexibility of the pipe thereby to determine a result obtained by correcting the basic position by the displacement amount as the position of the slave piston; and

a second arithmetic processing element configured to control the position of the master piston on a basis of the position of the slave piston determined by the first arithmetic processing element.

4. A piece of control software stored on a non-transitory computer readable medium for causing a computer to function as a system which controls a movement of a robot hand comprising a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, and for causing the computer to carry out:

first arithmetic processing for calculating a basic position of the slave piston in a state, wherein a diameter of the pipe remains unchanged, on a basis of a measured position of the master piston and an area ratio of the master piston relative to the slave piston and also for calculating a displacement amount of the slave piston according to a change in a cross-sectional area of the pipe on a basis of a measured pressure of a fluid in the pipe, a length of the pipe, and a coefficient indicating flexibility of the pipe thereby to determine a result obtained by correcting the basic position by the displacement amount as the position of the slave piston; and

second arithmetic processing for controlling the position of the master piston on a basis of the position of the slave piston determined by the first arithmetic processing.

5. A control method of a robot hand having a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, the control method comprising the steps of:

measuring a position of the master piston;

measuring a pressure of the fluid in the pipe;

calculating a basic position of the slave piston in a state, wherein a diameter of the pipe remains unchanged, on a basis of a measured position of the master piston and an area ratio of the master piston relative to the slave piston;

calculating a displacement amount of the slave piston according to a change in a cross-sectional area of the pipe on a basis of a measured pressure of a fluid in the pipe, a length of the pipe, and a coefficient indicating flexibility of the pipe;

determining a result obtained by correcting the basic position by the displacement amount as a position of the slave piston; and

controlling the position of the master piston on a basis of a measured position of the slave piston.

6. A control system of a robot hand having a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, the control system including a controller configured to control a bending and stretching operation of the finger mechanisms,

wherein the bending and stretching operation of the finger mechanisms is controlled by adjusting an outflow amount of a fluid from the master cylinder to the pipe on a basis of a difference between a measured outflow pressure of the fluid from the master cylinder to the pipe and a measured inflow pressure of the fluid from the pipe to the slave cylinder.

7. A robot hand comprising a plurality of finger mechanisms extended from a palm portion;

a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward;

a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward; and

a control system, further comprising;

a first fluid pressure sensor which outputs a signal based on an outflow pressure of a fluid from the master cylinder to the pipe;

a second fluid pressure sensor which outputs a signal based on an inflow pressure of the fluid from the pipe to the slave cylinder,

wherein the control system is configured to control a bending and stretching operation of each of the finger mechanisms by adjusting an outflow amount of a fluid from the master cylinder to the pipe on a basis of a difference between a measured outflow pressure of the fluid from the master cylinder to the pipe indicated by an output signal of the first fluid pressure sensor and a measured inflow pressure of the fluid from the pipe to the slave cylinder indicated by an output signal of the second fluid pressure sensor.

8. A piece of control software stored on a non-transitory computer readable medium for causing a computer to function as a system which controls a movement of a robot hand comprising a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, and for causing the computer to carry out:

arithmetic processing for controlling a bending and stretching operation of each of the finger mechanisms by adjusting an outflow amount of a fluid from the master cylinder to the pipe on a basis of a difference between a measured outflow pressure of the fluid from the master cylinder to the pipe and a measured inflow pressure of the fluid from the pipe to the slave cylinder.

9. A control method of a robot hand having a plurality of finger mechanisms extended from a palm portion, a slave cylinder for moving each of the plurality of finger mechanisms by moving a slave piston forward and backward, and a master cylinder which transmits a fluid pressure to the slave cylinder through a pipe by moving a master piston forward and backward, the control method comprising the steps of:

measuring an outflow pressure of a fluid from the master cylinder to the pipe;

measuring an inflow pressure of the fluid from the pipe to the slave cylinder; and

controlling a bending and stretching operation of each of the finger mechanisms by adjusting an outflow amount of a fluid from the master cylinder to the pipe on a basis of a difference between a measured outflow pressure of the fluid from the master cylinder to the pipe and a measured inflow pressure of the fluid from the pipe to the slave cylinder.